National pattern for heavy metal contamination of topsoil in remote farmland impacted by haze pollution in China

NASA Astrophysics Data System (ADS)

Luo, Zhuanxi; Gao, Meirong; Luo, Xiaosan; Yan, Changzhou

2016-03-01

The influence of haze pollution on heavy metal transport into farmland topsoil has received little attention. This study reports on heavy metal concentrations in topsoil from remote farmland in China as well as the spatial similarity and correlation to such heavy metals in atmospheric particulate matter (APM). Heavy metal concentrations in topsoil from remote farmland significantly increased over time. Moreover, stations in the mid-eastern region of China accounted for greater than 55% of total stations that exhibited higher concentrations in 2010 than 2005. This spatial trend was consistent with changes observed in APM where mass concentrations of heavy metals were also found to be higher in the mid-eastern region of China. Heavy metals in APM have already likely caused contamination in remote farmland topsoil, particularly in the mid-eastern region of China. This is primarily due to long-range transport and deposition of APM owing that no pesticides or fertilizers have been used in the remote farmland stations selected and no industries were situated nearby. Regarding the large-scale, severe haze pollution occurring in China today, it is urgent to ascertain the accumulation of heavy metals in farmland topsoil resulting from APM as well as its subsequent potential mechanisms and ecological risks.

[Development and succession of artificial biological soil crusts and water holding characteristics of topsoil].

PubMed

Wu, Li; Chen, Xiao-Guo; Zhang, Gao-Ke; Lan, Shu-Bin; Zhang, De-Lu; Hu, Chun-Xiang

2014-03-01

In order to understand the improving effects of cyanobacterial inoculation on water retention of topsoil in desert regions, this work focused on the development and succession of biological soil crusts and water holding characteristics of topsoil after cyanobacterial inoculation in Qubqi Desert. The results showed that after the artificial inoculation of desert cyanobacteria, algal crusts were quickly formed, and in some microenvironments direct succession of the algal crusts to moss crusts occurred after 2-3 years. With the development and succession of biological soil crusts, the topsoil biomass, polysaccharides content, crust thickness and porosity increased, while the soil bulk density decreased. At the same time, with crust development and succession, the topsoil texture became finer and the percents of fine soil particles including silt and clay contents increased, while the percents of coarse soil particles (sand content) decreased proportionately. In addition, it was found that with crust development and succession, the water holding capacity and water content of topsoil showed an increasing trend, namely: moss crust > algal crusts > shifting sand. The water content (or water holding capacity) in algal and moss crusts were 1.1-1.3 and 1.8-2.2 times of those in shifting sand, respectively. Correlation analysis showed that the water holding capacity and water content of topsoil were positively correlated with the crust biomass, polysaccharides content, thickness, bulk density, silt and clay content; while negatively correlated with the porosity and sand content. Furthermore, stepwise regression analysis showed that the main factor affecting water content was the clay content, while that affecting water holding capacity was the porosity.

Linking soil moisture balance and source-responsive models to estimate diffuse and preferential components of groundwater recharge

USGS Publications Warehouse

Cuthbert, M.O.; Mackay, R.; Nimmo, J.R.

2012-01-01

Results are presented of a detailed study into the vadose zone and shallow water table hydrodynamics of a field site in Shropshire, UK. A conceptual model is developed and tested using a range of numerical models, including a modified soil moisture balance model (SMBM) for estimating groundwater recharge in the presence of both diffuse and preferential flow components. Tensiometry reveals that the loamy sand topsoil wets up via macropore flow and subsequent redistribution of moisture into the soil matrix. Recharge does not occur until near-positive pressures are achieved at the top of the sandy glaciofluvial outwash material that underlies the topsoil, about 1 m above the water table. Once this occurs, very rapid water table rises follow. This threshold behaviour is attributed to the vertical discontinuity in the macropore system due to seasonal ploughing of the topsoil, and a lower permeability plough/iron pan restricting matrix flow between the topsoil and the lower outwash deposits. Although the wetting process in the topsoil is complex, a SMBM is shown to be effective in predicting the initiation of preferential flow from the base of the topsoil into the lower outwash horizon. The rapidity of the response at the water table and a water table rise during the summer period while flow gradients in the unsaturated profile were upward suggest that preferential flow is also occurring within the outwash deposits below the topsoil. A variation of the source-responsive model proposed by Nimmo (2010) is shown to reproduce the observed water table dynamics well in the lower outwash horizon when linked to a SMBM that quantifies the potential recharge from the topsoil. The results reveal new insights into preferential flow processes in cultivated soils and provide a useful and practical approach to accounting for preferential flow in studies of groundwater recharge estimation.

Synchrotron-based P K-edge XANES spectroscopy reveals rapid changes of phosphorus speciation in the topsoil of two glacier foreland chronosequences

NASA Astrophysics Data System (ADS)

Prietzel, Jörg; Dümig, Alexander; Wu, Yanhong; Zhou, Jun; Klysubun, Wantana

2013-05-01

Phosphorus (P) is a crucial element for life on Earth, and the bioavailability of P in terrestrial ecosystems, which is dependent on the soil P stock and its speciation, may limit ecosystem productivity and succession. In our study, for the first time a direct speciation of soil P in two glacier foreland chronosequences has been conducted using synchrotron-based X-ray Absorption Near-Edge Structure (XANES) spectroscopy. The chronosequences are located in the forefields of Hailuogou Glacier (Gongga Shan, China) and Damma Glacier (Swiss Alps). The age since deglaciation of the investigated soils ranges from 0 to 120 years at Hailuogou, and from 15 to >700 years at Damma. Differences in climate conditions (cooler at Damma, in contrast to Hailuogou precluding the establishment of forest in advanced ecosystem succession stages) and in the chemical composition of the parent material result in different soil contents of total P and Fe/Al oxyhydroxides, which are much smaller at Damma than at Hailuogou. Nevertheless, both chronosequences show similar trends of their topsoil P status with increasing soil age. Our study reveals a rapid change of topsoil P speciation in glacier retreat areas already during initial stages of pedogenesis: Initially dominating bedrock-derived apatite-P and Al-bound P is depleted; Fe-bound P and particularly organically-bound P is accumulated. Organic P strongly dominates in the topsoil of the mature soils outside the proglacial area of Damma Glacier (age 700-3000 years), and already 50 years after deglacation in the topsoil of the retreat area of Hailuogou Glacier. A key factor for the change in topsoil P speciation is the establishment of vegetation, resulting in soil organic matter (SOM) accumulation as well as accelerated soil acidification and apatite dissolution by organic acids, which are produced by SOM-degrading micro-organisms, mykorrhiza fungi, and plant roots. Particularly the succession of grassland to forest seems to accelerate the transformation of topsoil P from apatite-P into organic P. The conceptual model developed by Walker and Syers (1976) to explain long-term (millennial) changes of P speciation, availability, and turnover in soils and terrestrial ecosystems seems to be valid to describe short-term changes of P speciation and P availability in proglacial topsoils already within a century of initial soil formation. Because the apatite-depleted topsoil horizons in the young proglacial soils are shallow, the change of topsoil P speciation should not seriously affect P availability and the P acquisition strategy of adult trees, whose roots can easily access apatite-containing C horizons. In contrast, P acquisition strategies of fungi, micro-organisms and plants confined to the topsoil probably change from apatite dissolution to mineralization of organic P already within <3000 years in a proglacial ecosystem succession from bare soil to grassland (Damma Glacier Chronosequence) or even within <100 years in a proglacial ecosystem succession to forest (Hailuogou Glacier Chronosequence).

Effects of Nitrogen and Phosphorus Fertilizer and Topsoil Amendment on Native Plant Cover in Roadside Revegetation Projects

NASA Astrophysics Data System (ADS)

Hillhouse, Heidi L.; Schacht, Walter H.; Soper, Jonathan M.; Wienhold, Carol E.

2018-01-01

Establishing vegetation on roadsides following construction can be challenging, especially for relatively slow growing native species. Topsoil is generally removed during construction, and the surface soil following construction ("cut-slope soils") is often compacted and low in nutrients, providing poor growing conditions for vegetation. Nebraska Department of Transportation (NDOT) protocols have historically called for nitrogen (N) and phosphorus (P) fertilization when planting roadside vegetation following construction, but these recommendations were developed for cool-season grass plantings and most current plantings use slower-establishing, native warm-season grasses that may benefit less than expected from current planting protocols. We evaluated the effects of nitrogen and phosphorus fertilization, and also topsoil amendment, on the foliar cover of seeded and non-seeded species planted into two post-construction roadside sites in eastern Nebraska. We also examined soil movement to determine how planting protocols and plant growth may affect erosion potential. Three years after planting, we found no consistent effects of N or P fertilization on foliar cover. Plots receiving topsoil amendment had 14% greater cover of warm-season grasses, 10% greater total foliar cover, and 4-13% lower bare ground (depending on site) than plots without topsoil. None of the treatments consistently affected soil movement. We recommend that NDOT change their protocols to remove N and P fertilization and focus on stockpiling and spreading topsoil following construction.

Potential enzyme activities in cryoturbated organic matter of arctic soils

NASA Astrophysics Data System (ADS)

Schnecker, J.; Wild, B.; Rusalimova, O.; Mikutta, R.; Guggenberger, G.; Richter, A.

2012-12-01

An estimated 581 Gt organic carbon is stored in arctic soils that are affected by cryoturbtion, more than in today's atmosphere (450 Gt). The high amount of organic carbon is, amongst other factors, due to topsoil organic matter (OM) that has been subducted by freeze-thaw processes. This cryoturbated OM is usually hundreds to thousands of years old, while the chemical composition remains largely unaltered. It has therefore been suggested, that the retarded decomposition rates cannot be explained by unfavourable abiotic conditions in deeper soil layers alone. Since decomposition of soil organic material is dependent on extracellular enzymes, we measured potential and actual extracellular enzyme activities in organic topsoil, mineral subsoil and cryoturbated material from three different tundra sites, in Zackenberg (Greenland) and Cherskii (North-East Siberia). In addition we analysed the microbial community structure by PLFAs. Hydrolytic enzyme activities, calculated on a per gram dry mass basis, were higher in organic topsoil horizons than in cryoturbated horizons, which in turn were higher than in mineral horizons. When calculated on per gram carbon basis, the activity of the carbon acquiring enzyme exoglucanase was not significantly different between cryoturbated and topsoil organic horizons in any of the three sites. Oxidative enzymes, i.e. phenoloxidase and peroxidase, responsible for degradation of complex organic substances, showed higher activities in topsoil organic and cryoturbated horizons than in mineral horizons, when calculated per gram dry mass. Specific activities (per g C) however were highest in mineral horizons. We also measured actual cellulase activities (by inhibiting microbial uptake of products and without substrate addition): calculated per g C, the activities were up to ten times as high in organic topsoil compared to cryoturbated and mineral horizons, the latter not being significantly different. The total amount of PLFAs, as a proxy for microbial biomass, was significantly higher in topsoil organic horizons than in cryoturbated and mineral horizons. Changes in the microbial community composition were mainly caused by the relative amount of fungal biomarkers. Within the fungal community the biomarker 18:2w6, which is often associated with ectomycorrhiza, was negatively correlated to the general fungal biomarker 18:1w9. This negative correlation indicates a shift from mycorrhizal to saprotrophic fungi from topsoil towards cryoturbatad and mineral subsoil horizons. In summary, the measured oxidative and hydrolytic (potential) enzyme activities cannot explain the previously observed retarded decomposition in cryoturbated horizons. The measured actual cellulase activity however was strongly reduced in cryoturbated material compared to topsoil horizons. A possible explanation for the observed strong reduction of actual cellulase activity could lie within the fungal community structure which shifted towards saprotrophic fungi from topsoil to cryoturbated horizons.

Association between heavy metal and metalloid levels in topsoil and cancer mortality in Spain.

PubMed

Núñez, Olivier; Fernández-Navarro, Pablo; Martín-Méndez, Iván; Bel-Lan, Alejandro; Locutura Rupérez, Juan F; López-Abente, Gonzalo

2017-03-01

Spatio-temporal cancer mortality studies in Spain have revealed patterns for some tumours which display a distribution that is similar across the sexes and persists over time. Such characteristics would be common to tumours that shared risk factors, including the geochemical composition of the soil. The aim of this study was to assess the possible association between heavy metal and metalloid levels in topsoil (upper soil horizon) and cancer mortality in mainland Spain. Ecological cancer mortality study at a municipal level, covering 861,440 cancer deaths (27 different tumour locations) in 7917 Spanish mainland towns, from 1999 to 2008. The elements included in this analysis were Al, As, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn. Topsoil levels (partial extraction) were determined by ICP-MS at 13,317 sampling points. For the analysis, the data on the topsoil composition have been transformed by the centred logratio (clr-transformation). Principal factor analysis was performed to obtain independent latent factors for the transformed variables. To estimate the effect of heavy metal levels in topsoil composition on mortality, we fitted Besag, York and Mollié models, which included each town's factor scores as the explanatory variable. Integrated Nested Laplace Approximation (INLA) was used as a tool for Bayesian inference. All results were adjusted for sociodemographic variables. The results showed an association between trace contents of heavy metals and metalloids in topsoil and mortality due to tumours of the digestive system in mainland Spain. This association was observed in both sexes, something that would support the hypothesis that the incorporation of heavy metals into the trophic chain might be playing a role in the aetiology of some types of cancer. Topsoil composition and the presence of potentially toxic elements in trace concentrations might be an additional component in the aetiology of some types of cancer, and go some way to determine the ensuing geographic differences in mortality in Spain. The results support the interest of inclusion of heavy metal levels in topsoil as a hypothesis in analytical epidemiological studies using biological markers of exposure to heavy metals and metalloids.

Performance of erosion control treatments on reapplied topsoil.

DOT National Transportation Integrated Search

2005-05-01

Roadside revegetation projects present substantial challenges to successful development of : desired plant associations and vegetation structure. Cut or fill slopes are often steeply inclined, : highly compacted, and lacking topsoil. Excavated topsoi...

[Effects of Suaeda glauca planting and straw mulching on soil salinity dynamics and desalination in extremely heavy saline soil of coastal areas.

PubMed

Zhang, Jiao; Cui, Shi You; Feng, Zhi Xiang

2018-05-01

To elucidate the seasonal variations in soil salinity and its driving factors, and to explore the effects of planting Suaeda glauca and straw mulching on soil desalination and salinity controlling, a field experiment was conducted in extremely heavy saline soil of coastal areas in Rudong, Jiangsu Province. There were four treatments: control (bare land, CK), planting S. glauca (PS), straw mulching A (at 15 t·hm -2 , SM-A), straw mulching 2A (at 30 t·hm -2 , SM-2A). Climate factors (including rainfall, atmospheric temperature, sunshine duration, and atmospheric evaporation) and soil salinity dynamic changes were determined from May 2014 to May 2015. Results showed that: (1) The seasonal variation of soil salinity was obvious in the bare ground (CK), with the lowest (8.69 g·kg -1 ) during June-August and the highest (26.66 g·kg -1 ) during September-December. The changes of soil salinity in topsoil (0-20 cm) were more intense than that in sub-topsoil (20-40 cm), with the changes in sub-topsoil having somewhat time lag compared the topsoil. (2) Soil salinity in CK treatment had a significantly linear correlation with the cumulative rainfall and evaporation-precipitation ratio of the fifteen-day before sampling. The results from multifactor and interphase analysis indicated that the increases of rainfall would promote soil desalinization. The rise of atmospheric temperature could exacerbate soil salt accumulation in surface soil. The interaction between rainfall and atmospheric temperature would have a positive effect on soil salt accumulation. (3) PS treatment did not alter the seasonal variation in soil salinity, but it reduced soil salinity in topsoil. (4) In SM-A and SM-2A treatments, the relationship of soil desalinization rate (%, Y) and treatment time (days, X) was expressed as Logistic curve equation. Moreover, the soil desalination rate was over 95.0% in the topsoil after 90-100 days of straw mul-ching treatment and was over 92.0% in sub-topsoil after 120 days of straw mulching treatment. The soil salinity in SM-A and SM-2A treatments fluctuated below 0.60 g·kg -1 and 1.00 g·kg -1 , respectively in topsoil and sub-topsoil. Considering the desalination and economic costs, a suitable amount of straw mulching (such as 15 t·hm -2 ) before rainy season was recommended, which would promote the soil desalinization and reclamation in extremely heavy saline soil of coastal areas.

Fine resolution map of top- and subsoil carbon sequestration potential in France.

PubMed

Chen, Songchao; Martin, Manuel P; Saby, Nicolas P A; Walter, Christian; Angers, Denis A; Arrouays, Dominique

2018-07-15

Although soils have a high potential to offset CO 2 emissions through its conversion into soil organic carbon (SOC) with long turnover time, it is widely accepted that there is an upper limit of soil stable C storage, which is referred to SOC saturation. In this study we estimate SOC saturation in French topsoil (0-30cm) and subsoil (30-50cm), using the Hassink equation and calculate the additional SOC sequestration potential (SOC sp ) by the difference between SOC saturation and fine fraction C on an unbiased sampling set of sites covering whole mainland France. We then map with fine resolution the geographical distribution of SOC sp over the French territory using a regression Kriging approach with environmental covariates. Results show that the controlling factors of SOC sp differ from topsoil and subsoil. The main controlling factor of SOCsp in topsoils is land use. Nearly half of forest topsoils are over-saturated with a SOC sp close to 0 (mean and standard error at 0.19±0.12) whereas cropland, vineyard and orchard soils are largely unsaturated with degrees of C saturation deficit at 36.45±0.68% and 57.10±1.64%, respectively. The determinant of C sequestration potential in subsoils is related to parent material. There is a large additional SOC sp in subsoil for all land uses with degrees of C saturation deficit between 48.52±4.83% and 68.68±0.42%. Overall the SOCsp for French soils appears to be very large (1008Mt C for topsoil and 1360Mt C for subsoil) when compared to previous total SOC stocks estimates of about 3.5Gt in French topsoil. Our results also show that overall, 176Mt C exceed C saturation in French topsoil and might thus be very sensitive to land use change. Crown Copyright © 2018. Published by Elsevier B.V. All rights reserved.

Organic Fertilization and Sufficient Nutrient Status in Prehistoric Agriculture? – Indications from Multi-Proxy Analyses of Archaeological Topsoil Relicts

PubMed Central

Lauer, Franziska; Prost, Katharina; Gerlach, Renate; Pätzold, Stefan; Wolf, Mareike; Urmersbach, Sarah; Lehndorff, Eva; Eckmeier, Eileen; Amelung, Wulf

2014-01-01

Neolithic and Bronze Age topsoil relicts revealed enhanced extractable phosphorus (P) and plant available inorganic P fractions, thus raising the question whether there was targeted soil amelioration in prehistoric times. This study aimed (i) at assessing the overall nutrient status and the soil organic matter content of these arable topsoil relicts, and (ii) at tracing ancient soil fertilizing practices by respective stable isotope and biomarker analyses. Prehistoric arable topsoils were preserved in archaeological pit fillings, whereas adjacent subsoils served as controls. One Early Weichselian humic zone represented the soil status before the introduction of agriculture. Recent topsoils served as an additional reference. The applied multi-proxy approach comprised total P and micronutrient contents, stable N isotope ratios, amino acid, steroid, and black carbon analyses as well as soil color measurements. Total contents of P and selected micronutrients (I, Cu, Mn, Mo, Se, Zn) of the arable soil relicts were above the limits for which nutrient deficiencies could be assumed. All pit fillings exhibited elevated δ15N values close to those of recent topsoils (δ15N>6 to 7‰), giving first hints for prehistoric organic N-input. Ancient legume cultivation as a potential source for N input could not be verified by means of amino acid analysis. In contrast, bile acids as markers for faecal input exhibited larger concentrations in the pit fillings compared with the reference and control soils indicating faeces (i.e. manure) input to Neolithic arable topsoils. Also black carbon contents were elevated, amounting up to 38% of soil organic carbon, therewith explaining the dark soil color in the pit fillings and pointing to inputs of burned biomass. The combination of different geochemical analyses revealed a sufficient nutrient status of prehistoric arable soils, as well as signs of amelioration (inputs of organic material like charcoal and faeces-containing manure). PMID:25180911

Native-plant amendments and topsoil addition enhance soil function in post-mining arid grasslands.

PubMed

Kneller, Tayla; Harris, Richard J; Bateman, Amber; Muñoz-Rojas, Miriam

2018-04-15

One of the most critical challenges faced in restoration of disturbed arid lands is the limited availability of topsoil. In post-mining restoration, alternative soil substrates such as mine waste could be an adequate growth media to alleviate the topsoil deficit, but these materials often lack appropriate soil characteristics to support the development and survival of seedlings. Thus, addition of exogenous organic matter may be essential to enhance plant survival and soil function. Here, we present a case study in the arid Pilbara region (north-west Western Australia), a resource-rich area subject to intensive mining activities. The main objective of our study was to assess the effects of different restoration techniques such as soil reconstruction by blending available soil materials, sowing different compositions of plant species, and addition of a locally abundant native soil organic amendment (Triodia pungens biomass) on: (i) seedling recruitment and growth of Triodia wiseana, a dominant grass in Australian arid ecosystems, and (ii) soil chemical, physical, and biological characteristics of reconstructed soils, including microbial activity, total organic C, total N, and C and N mineralisation. The study was conducted in a 12-month multifactorial microcosms setting in a controlled environment. Our results showed that the amendment increased C and N contents of re-made soils, but these values were still lower than those obtained in the topsoil. High microbial activity and C mineralisation rates were found in the amended waste that contrasted the low N mineralisation but this did not translate into improved emergence or survival of T. wiseana. These results suggest a short- or medium-term soil N immobilisation caused by negative priming effect of fresh un-composted amendment on microbial communities. We found similar growth and survival rates of T. wiseana in topsoil and a blend of topsoil and waste (50:50) which highlights the importance of topsoil, even in a reduced amount, for plant establishment in arid land restoration. Copyright © 2017 Elsevier B.V. All rights reserved.

Short-chain chlorinated paraffins in the soils of two different Chinese cities: Occurrence, homologue patterns and vertical migration.

PubMed

Huang, Yumei; Chen, Laiguo; Feng, Yongbin; Ye, Zhixiang; He, Qiusheng; Feng, Qianhua; Qing, Xian; Liu, Ming; Gao, Bo

2016-07-01

Short-chain chlorinated paraffins (SCCPs) are candidate persistent organic pollutants (POPs) that are under review by the Stockholm Convention. China is currently the largest producer and consumer of chlorinated paraffins (CPs). To study the environmental behavior and fate of SCCPs in the soils of urban and suburban regions, the SCCP concentrations in 88 topsoils and 15 soil columns from land of different use types (e.g., woodland, vegetable field, paddy field and greenbelt) from Guangzhou and Chengdu have been determined. The SCCP concentrations in topsoils from Guangzhou (range: 1.45-25.5ngg(-1) dry weight (dw), average: 10.3ngg(-1) dw) were much higher than those from Chengdu (range: 0.218-3.26ngg(-1) dw, average: 1.43ngg(-1) dw). When compared to previously reported SCCP levels for topsoils from other areas, the SCCP concentrations measured in the present work were quite low. Much higher SCCP concentrations were observed in the greenbelt topsoils from Chengdu relative to the values measured from woodlands and vegetable and paddy fields. The composition profiles suggest that C10Cl6-10 and C11-13Cl6-8 were the major groups of SCCPs in topsoils from the woodlands and vegetable and paddy fields in Guangzhou and Chengdu. Vertical variations of the SCCP concentrations in the soil columns suggest that less chlorinated SCCPs (Cl5-6-SCCPs) are more capable of migrating to the deeper-layer soils than more chlorinated ones (Cl9-10-SCCPs). The SCCP concentrations displayed little dependence on organic matter (OM) for most topsoils (p>0.05), indicating that OM is not the controlling factor in the distribution of SCCPs in the soils. This study analyzed the occurrence, homologue patterns and vertical migration of SCCPs in the topsoils of two Chinese cities with different industrial structures and climate conditions. Copyright © 2016 Elsevier B.V. All rights reserved.

Distinct microbial communities associated with buried soils in the Siberian tundra

PubMed Central

Gittel, Antje; Bárta, Jiří; Kohoutová, Iva; Mikutta, Robert; Owens, Sarah; Gilbert, Jack; Schnecker, Jörg; Wild, Birgit; Hannisdal, Bjarte; Maerz, Joeran; Lashchinskiy, Nikolay; Čapek, Petr; Šantrůčková, Hana; Gentsch, Norman; Shibistova, Olga; Guggenberger, Georg; Richter, Andreas; Torsvik, Vigdis L; Schleper, Christa; Urich, Tim

2014-01-01

Cryoturbation, the burial of topsoil material into deeper soil horizons by repeated freeze–thaw events, is an important storage mechanism for soil organic matter (SOM) in permafrost-affected soils. Besides abiotic conditions, microbial community structure and the accessibility of SOM to the decomposer community are hypothesized to control SOM decomposition and thus have a crucial role in SOM accumulation in buried soils. We surveyed the microbial community structure in cryoturbated soils from nine soil profiles in the northeastern Siberian tundra using high-throughput sequencing and quantification of bacterial, archaeal and fungal marker genes. We found that bacterial abundances in buried topsoils were as high as in unburied topsoils. In contrast, fungal abundances decreased with depth and were significantly lower in buried than in unburied topsoils resulting in remarkably low fungal to bacterial ratios in buried topsoils. Fungal community profiling revealed an associated decrease in presumably ectomycorrhizal (ECM) fungi. The abiotic conditions (low to subzero temperatures, anoxia) and the reduced abundance of fungi likely provide a niche for bacterial, facultative anaerobic decomposers of SOM such as members of the Actinobacteria, which were found in significantly higher relative abundances in buried than in unburied topsoils. Our study expands the knowledge on the microbial community structure in soils of Northern latitude permafrost regions, and attributes the delayed decomposition of SOM in buried soils to specific microbial taxa, and particularly to a decrease in abundance and activity of ECM fungi, and to the extent to which bacterial decomposers are able to act as their functional substitutes. PMID:24335828

Mineralisation and degradation of 2,4-dichlorophenoxyacetic acid dimethylamine salt in a biobed matrix and in topsoil.

PubMed

Knight, J Diane; Cessna, Allan J; Ngombe, Dean; Wolfe, Tom M

2016-10-01

Biobeds are used for on-farm bioremediation of pesticides in sprayer rinsate and from spills during sprayer filling. Using locally sourced materials from Saskatchewan, Canada, a biobed matrix was evaluated for its effectiveness for mineralising and degrading 2,4-dichlorophenoxyacetic acid dimethylamine salt (2,4-D DMA) compared with the topsoil used in the biobed matrix. Applying 2,4-D DMA to the biobed matrix caused a 2-3 day lag in CO2 production not observed when the herbicide was applied to topsoil. Despite the initial lag, less residual 2,4-D was measured in the biobed (0%) matrix than in the topsoil (57%) after a 28 day incubation. When the herbicide was applied 5 times to the biobed matrix, net CO2 increased immediately after each 2,4-D DMA application. Mineralisation of 2,4-D DMA was 61.9% and residual 2,4-D in the biobed matrix was 0.3% after 60 days, compared with corresponding values of 32.9 and 70.9% in topsoil. The biobed matrix enhanced the mineralisation and degradation of 2,4-D DMA, indicating the potential for successful implementation of biobeds under Canadian conditions. The biobed matrix was more effective for mineralising and degrading the herbicide compared with the topsoil used in the biobed matrix. By correcting for biobed matrix and formulation blank, CO2 evolution was a reliable indicator of 2,4-D DMA mineralisation. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Epifluorescent direct counts of bacteria and viruses from topsoil of various desert dust storm regions

USGS Publications Warehouse

Gonzalez-Martin, Cristina; Teigell-Perez, Nuria; Lyles, Mark; Valladares, Basilio; Griffin, Dale W.

2013-01-01

Topsoil from arid regions is the main source of dust clouds that move through the earth's atmosphere, and microbial communities within these soils can survive long-range dispersion. Microbial abundance and chemical composition were analyzed in topsoil from various desert regions. Statistical analyses showed that microbial direct counts were strongly positively correlated with calcium concentrations and negatively correlated with silicon concentrations. While variance between deserts was expected, it was interesting to note differences between sample sites within a given desert region, illustrating the 'patchy' nature of microbial communities in desert environments.

A comparison of the efficacy and ecosystem impact of residual-based and topsoil-based amendments for restoring historic mine tailings in the Tri-State mining district.

PubMed

Brown, Sally; Mahoney, Michele; Sprenger, Mark

2014-07-01

A long-term research and demonstration site was established on Pb and Zn mine wastes in southwestern Missouri in 1999. Municipal biosolids and lime and composts were mixed into the wastes at different loading rates. The site was monitored intensively after establishment and again in 2012. A site restored with topsoil was also included in the 2012 sampling. Initial results including plant, earthworm and small mammal assays indicate that the bioaccessibility of metals had been significantly reduced as a result of amendment addition. The recent sampling showed that at higher loading rates, the residual mixtures have maintained a vegetative cover and are similar to the topsoil treatment based on nutrient availability and cycling and soil physical properties including bulk density and water holding capacity. The ecosystem implications of restoration with residuals versus mined topsoil were evaluated. Harvesting topsoil from nearby farms would require 1875 years to replace based on natural rates of soil formation. In contrast, diverting biosolids from combustion facilities (60% of biosolids generated in Missouri are incinerated) would result in greenhouse gas savings of close to 400 Mg CO2 per ha. Copyright © 2014 Elsevier B.V. All rights reserved.

Contamination, source, and input route of polycyclic aromatic hydrocarbons in historic wastewater-irrigated agricultural soils.

PubMed

Wang, Ning; Li, Hong-Bo; Long, Jin-Lin; Cai, Chao; Dai, Jiu-Lan; Zhang, Juan; Wang, Ren-Qing

2012-12-01

Contamination by polycyclic aromatic hydrocarbons (PAHs) of historic wastewater-irrigated agricultural topsoil (0-5 cm) and the contribution of groundwater irrigation and atmospheric deposition to soil PAHs were studied in a typical agricultural region, i.e. Hunpu region, Liaoning, China. Concentrations of total PAHs ranged from 0.43 to 2.64 mg kg⁻¹ in topsoil, being lower than those found in other wastewater-irrigated areas. The levels of PAHs in soil declined as the distance from a water source increased. Concentrations of individual PAHs were generally higher in upland than in paddy topsoils. The calculated nemerow composite index showed that agricultural soil in the region was "polluted" by PAHs. A human health risk assessment based on the total toxic equivalent concentration showed that the presence of elevated concentrations of PAHs in the soil might pose a great threat to the health of local residents. Ratios of pairs of PAHs and principal component analysis (PCA) showed that pyrogenesis, such as coal combustion, was the main source of PAHs, while petroleum, to some extent, also had a strong influence on PAHs contamination in upland soil. The distribution patterns of individual PAHs and composition of PAHs differed between irrigation groundwater and topsoil, but were similar between atmospheric deposition and topsoil. There were significant linear correlations (r = 0.90; p < 0.01) between atmospheric deposition rates and average concentrations of the 16 individual PAHs in soils, while no significant relationships were observed between irrigation groundwater and topsoil in levels of PAHs. These suggested that PAHs in agricultural soils were mainly introduced from atmospheric deposition, rather than from groundwater irrigation after the phasing out of wastewater irrigation in the region since 2002. This study provides a reference to ensure agricultural product safety, pollution control, and proper soil management.

Environmental remediation following the Fukushima-Daiichi accident

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tagawa, A.; Miyahara, K.; Nakayama, S.

2013-07-01

A wide area of Fukushima Prefecture was contaminated with radioactivity released by the Fukushima Daiichi nuclear accident. The decontamination pilot projects conducted by JAEA aimed at demonstrating the applicability of different techniques to rehabilitate affected areas. As most radioactive cesium is concentrated at the top of the soil column and strongly bound to mineral surfaces, there are 3 options left to decrease the gamma dose rate (usually measured 1 m above the ground surface): the stripping of the contaminated topsoil (i.e. direct removal of cesium), the dilution by mixing and the soil profile inversion. The last two options do notmore » generate waste. As the half-distance of {sup 137}Cs gammas in soil is in the order of 5-6 cm (depending on density and water content), the shielding by 50 cm of uncontaminated deep soil would theoretically reduce gamma doses by about 3 orders of magnitude. Which option is employed depends basically on the Cesium concentration in the topsoil, averaged over a 15-cm thickness. The JAEA's decontamination pilot projects focus on soil profile inversion and topsoil stripping. Two different techniques have been tested for the soil profile inversion: one is the reversal tillage by which surface soil of thickness of several tens of cm is reversed by using a tractor plough and the other is the complete interchanging of contaminated topsoil with uncontaminated subsoil by using a back-hoe. Reversal tillage with a tractor plough cost about 30 yen/m{sup 2}, which is an order of magnitude lower than that of topsoil-subsoil interchange (about 300 yen/m{sup 2}). Topsoil stripping is significantly more costly (between 550 yen/m{sup 2} and 690 yen/m{sup 2} according to the equipment used)« less

Crop Performance and Soil Properties in Two Artificially-Eroded Soils in North-Central Alberta

DOE Office of Scientific and Technical Information (OSTI.GOV)

Izaurralde, R Cesar C.; Malhi, S. S.; Nyborg, M.

2006-09-01

Field experiments were conducted from 1991 to 1995 at Josephburg (Orthic Black Chernozem, Typic Cryoboroll) and Cooking Lake (Orthic Gray Luvisol, Typic Cryoboralf), Alberta, to determine impact of topsoil removal on selected soil properties, N-mineralization potential and crop yield, and effectiveness of various amendments for restoring the productivity of eroded soils. The simulated-erosion levels were established in the autumn of 1990 by removing 20 cm topsoil in 5-cm depth increments. The four amendments were: control, addition of 5 cm of topsoil, fertilizers to supply 100 kg N ha-1 and 20 kg P ha-1, and cattle manure at 75 Mg ha-1.more » Topsoil and manure were applied once in the autumn of 1990, while fertilizers were applied annually from 1991 to 1995. Available N and P, total C, N and P, and N-mineralization potential decreased, while bulk density increased with increasing depth of topsoil removal. Tiller number, plant height, spike density, thousand kernel weight, and leaf area index decreased with simulated erosion. Grain yield reductions due to simulated soil erosion were either linear or curvilinear functions of nutrient removal. Application of N and P fertilizers and manure improved grain yield and reduced the impact of yield loss due to erosion. Return of 5 cm of topsoil also increased grain yield, but to a lesser extent than manure or fertilizers. Grain yields were maximized when fertilizers were also applied to organic amendment treatments. In conclusion, the findings suggest the importance of integrated use of organic amendments and chemical fertilizers for best crop yields on severely-eroded soils.« less

Topsoil and Deep Soil Organic Carbon Concentration and Stability Vary with Aggregate Size and Vegetation Type in Subtropical China

PubMed Central

Fang, Xiang-Min; Chen, Fu-Sheng; Wan, Song-Ze; Yang, Qing-Pei; Shi, Jian-Min

2015-01-01

The impact of reforestation on soil organic carbon (OC), especially in deep layer, is poorly understood and deep soil OC stabilization in relation with aggregation and vegetation type in afforested area is unknown. Here, we collected topsoil (0–15 cm) and deep soil (30–45 cm) from six paired coniferous forests (CF) and broad-leaved forests (BF) reforested in the early 1990s in subtropical China. Soil aggregates were separated by size by dry sieving and OC stability was measured by closed-jar alkali-absorption in 71 incubation days. Soil OC concentration and mean weight diameter were higher in BF than CF. The cumulative carbon mineralization (Cmin, mg CO2-C kg-1 soil) varied with aggregate size in BF and CF topsoils, and in deep soil, it was higher in larger aggregates than in smaller aggregates in BF, but not CF. The percentage of soil OC mineralized (SOCmin, % SOC) was in general higher in larger aggregates than in smaller aggregates. Meanwhile, SOCmin was greater in CF than in BF at topsoil and deep soil aggregates. In comparison to topsoil, deep soil aggregates generally exhibited a lower Cmin, and higher SOCmin. Total nitrogen (N) and the ratio of carbon to phosphorus (C/P) were generally higher in BF than in CF in topsoil and deep soil aggregates, while the same trend of N/P was only found in deep soil aggregates. Moreover, the SOCmin negatively correlated with OC, total N, C/P and N/P. This work suggests that reforested vegetation type might play an important role in soil OC storage through internal nutrient cycling. Soil depth and aggregate size influenced OC stability, and deep soil OC stability could be altered by vegetation reforested about 20 years. PMID:26418563

Topsoil thickness influences nitrogen management of switchgrass

USDA-ARS?s Scientific Manuscript database

Switchgrass (Panicum virgatum L.) is an attractive bioenergy crop option for eroded portions of claypan landscapes where grain crop production is marginally profitable. Topsoil thickness above the claypan or depth to claypan (DTC) can vary widely within fields and little information exists on its im...

Topsoil depth effects on corn yield and nitrogen uptake efficiency

USDA-ARS?s Scientific Manuscript database

Decades of erosion on claypan soil fields under row crop production has led to varying topsoil thickness across fields of the Midwest, resulting in variable crop fertilizer requirements across landscapes. Determining how these crop needs, specifically nitrogen, vary across fields is crucial for gett...

Tracing industrial heavy metal inputs to topsoils using using cadmium isotopes

NASA Astrophysics Data System (ADS)

Huang, Y.; Ma, L.; Ni, S.; Lu, H.; Liu, Z.; Zhang, C.; Guo, J.; Wang, N.

2015-12-01

Anthropogenic activities have dominated heavy metal (such as Cd, Pb, and Zn) cycling in many environments. The extent and fate of these metal depositions in topsoils, however, have not been adequately evaluated. Here, we utilize an innovative Cadmium (Cd) isotope tool to trace the sources of metal pollutants in topsoils collected from surrounding a Vanadium Titanium Magnetite smelting plant in Sichuan, China. Topsoil samples and possible pollution end-members such as fly ashes, bottom ashes, ore materials, and coal were also collected from the region surrounding the smelting plant and were analyzed for Cd isotope ratios (d114Cd relative to Cd NIST 3108). Large Cd isotope fractionation (up to 3 ‰) was observed in these industrial end-members: fly ashes possessed higher δ114Cd values ranging from +0.03 to +0.19‰; bottom fly ashes have lower δ114Cd values ranging from -0.35 to -2.46‰; and unprocessed ore and coal samples has δ114Cd value of -0.40‰. This fractionation can be attributed to the smelting processes during which bottom ashes acquired lighter Cd isotope signatures while fly ashes were mainly characterized by heavy isotope ratios, in comparison to the unprocessed ore and coal samples. Indeed, δ114Cd values of topsoils in the smelting area range from 0.29 to -0.56‰, and more than half of the soils analyzed have distinct δ114Cd values > 0‰. Cd isotopes and concentrations measured in topsoils suggested that processed materials (fly and bottom ashes from ore and coal actually used by the smelting plant) were the major source of Cd in soils. In a δ114Cd vs 1/Cd mixing diagram, the soils represent a mixture of three identified end members (fly ash, bottom ash and deep unaffected soil) with distinct Cd isotopic compositions and concentrations. Deep soils have the same δ114Cd values range as the unprocessed ore and coal, which indicated the Cd isotope fractionation did occur during evaporation and condensation processes inside the smelting plant. The signatures of fly ash end member might be even higher according to the δ114Cd increasing trend of topsoils with the increasing of Cd concentration of the topsoils. Our study suggested that δ114Cd values can be used to distinguish sources of anthropogenic Cd and to construct metal budgets in in this studying area.

Topsoil moisture mapping using geostatistical techniques under different Mediterranean climatic conditions.

PubMed

Martínez-Murillo, J F; Hueso-González, P; Ruiz-Sinoga, J D

2017-10-01

Soil mapping has been considered as an important factor in the widening of Soil Science and giving response to many different environmental questions. Geostatistical techniques, through kriging and co-kriging techniques, have made possible to improve the understanding of eco-geomorphologic variables, e.g., soil moisture. This study is focused on mapping of topsoil moisture using geostatistical techniques under different Mediterranean climatic conditions (humid, dry and semiarid) in three small watersheds and considering topography and soil properties as key factors. A Digital Elevation Model (DEM) with a resolution of 1×1m was derived from a topographical survey as well as soils were sampled to analyzed soil properties controlling topsoil moisture, which was measured during 4-years. Afterwards, some topography attributes were derived from the DEM, the soil properties analyzed in laboratory, and the topsoil moisture was modeled for the entire watersheds applying three geostatistical techniques: i) ordinary kriging; ii) co-kriging considering as co-variate topography attributes; and iii) co-kriging ta considering as co-variates topography attributes and gravel content. The results indicated topsoil moisture was more accurately mapped in the dry and semiarid watersheds when co-kriging procedure was performed. The study is a contribution to improve the efficiency and accuracy of studies about the Mediterranean eco-geomorphologic system and soil hydrology in field conditions. Copyright © 2017 Elsevier B.V. All rights reserved.

Degradation of pesticides in biobeds: the effect of concentration and pesticide mixtures.

PubMed

Fogg, Paul; Boxall, Alistair B A; Walker, Allan

2003-08-27

Biobeds aim to create an environment whereby any pesticide spills are retained and then degraded, thus reducing the potential for surface or groundwater contamination. Biobeds may receive high concentrations of relatively complex mixtures of pesticides. The effects of concentration and pesticide interaction on degradation rate were therefore investigated. At concentrations up to 20 times the maximum recommended application rate for isoproturon and chlorothalonil, the rate of degradation in topsoil and biomix decreased with increasing concentration. With the exception of isoproturon at concentrations above 11 mg kg(-1), degradation was quicker in biomix (a composted mixture of topsoil, compost, and wheat straw) than in topsoil. One possible explanation for faster isoproturon degradation in topsoil as compared to biomix may be that previous treatments of isoproturon applied to the field soil as part of normal agricultural practices had resulted in proliferation of microbial communities specifically adapted to use isoproturon as an energy source. Such microbial adaptation could enhance the performance of a biobed. Studies with a mixture of isoproturon and chlorothalonil showed that interactions between pesticides are possible. In biomix, the degradation of either isoproturon or chlorothalonil was unaffected by the presence of the other pesticide, whereas in topsoil, isoproturon DT(50) values increased from 18.5 to 71.5 days in the presence of chlorothalonil. These studies suggest that biobeds appear capable of treating high concentrations of more than one pesticide.

Soil quality changes after topsoil addition to eroded land

USDA-ARS?s Scientific Manuscript database

Soil-landscape rehabilitation within eroded fields can be accomplished by moving topsoil from depositional to eroded landscape positions. The purpose is to improve soil quality and productivity of the upper root zone in eroded areas of the field. Changes in soil quality may be estimated through chan...

Topsoil thickness and harvest management influence switchgrass production and profitability

USDA-ARS?s Scientific Manuscript database

Switchgrass (Panicum virgatum L.) is an attractive dual use forage and/or biomass crop option for eroded or marginal soils where corn (Zea mays L.) grain production often is not profitable. Topsoil thickness, especially above soils with a claypan, relates to crop productivity and nutrient removal an...

Evaluation of organic matter compost addition and incorporation on steep cut slopes. Phase II : test plot construction and performance monitoring

DOT National Transportation Integrated Search

2007-04-01

Erosion of steep highway cut slopes in Montana is often times the consequence of poor vegetation development in nutrient-poor growth media resulting from highway construction where topsoil cannot physically be replaced due to slope steepness. Topsoil...

Soil water infiltration affected by topsoil thickness in row crop and switchgrass production systems

USDA-ARS?s Scientific Manuscript database

Conversion of annual grain crop systems to biofuel production systems can restore soil hydrologic function; however, information on these effects is limited. Hence, the objective of this study was to evaluate the influence of topsoil thickness on water infiltration in claypan soils for grain and swi...

Impact of pilling and long-term topsoil storage on the potential soil microbial activity in the Northern Chihuahuan Desert

USDA-ARS?s Scientific Manuscript database

Cryptobiotic soil crusts in arid regions contribute to ecosystem stability through increased water infiltration, soil aggregate stability, and nutrient cycling between the soil community and vascular plants. Natural gas mining involves removal of the topsoil, including surface crust, and storage of ...

Topsoil thickness effects on corn, soybean, and switchgrass production on claypan soils

USDA-ARS?s Scientific Manuscript database

Diminished topsoil thickness or depth to claypan (DTC) is a major cause of yield and profit depression in corn (Zea mays L.) and to a lesser extent in soybean (Glycine max [L.]) production on claypan soils. Perennial grasses such as switchgrass (Panicum virgatum L.) may be more resilient to reduced ...

Rapid formation of rock armour for soil - rock fragment mixture during simulated rainfall

NASA Astrophysics Data System (ADS)

Poultney, E.; McGrath, G. S.; Hinz, C.

2009-04-01

Preventing erosion is an important issue in disturbed semi-arid and arid landscapes. This is in particular of highest importance for mining companies while undertaking land rehabilitation. An onsite investigation of the impact of surface rock fragments on erosion was conducted at Telfer goldmine in the Great Sandy Desert, Western Australia. The study site is a waste rock dump designed to mimic the concave slope of a natural mesa to both discourage erosion and blend in with its natural surroundings. Four treatments were used to construct the slope: two are topsoil mixed with rock fragments, and two are unmixed topsoil. A field study investigating erosion rills, particle size distribution, rock fragment coverage surface roughness and vegetation was carried out to determine changes down and across slope. The treatments constructed by mixing topsoil and rock fragments are more stable and show rock fragment distributions that more closely resemble patterns found on natural mesas surrounding Telfer. A controlled study using trays of topsoil mixed with rock fragment volumes of 50%, 60%, 70% and 80% were used to investigate how varying mixtures of rock fragments and topsoil erode using rainfall intensities between 20 and 100 mm h-1. Two runs of 25 minutes each were used to assess the temporal evolution of rock armouring. Surface coverage results converged for the 50%, 60% and 70% mixtures after the first run to coverage of about 90%, suggesting that fine sediment proportion does not affect rate and degree of rock armouring.

Growing Eremanthus erythropappus in crushed laterite: A promising alternative to topsoil for bauxite-mine revegetation.

PubMed

Machado, Naiara Amaral de Miranda; Leite, Mariangela Garcia Praça; Figueiredo, Maurílio Assis; Kozovits, Alessandra Rodrigues

2013-11-15

Topsoil is the preferred substrate for areas requiring rehabilitation after bauxite mining. However, topsoil is sometimes lacking and so there is a need to test the suitability of other, locally available substrates. In an abandoned bauxite mine in Southeastern Brazil, small patches of native vegetation spontaneously established in shallow depressions over weathered laterite, suggesting that granulometric reduction may have facilitated the establishment of plants. To test this hypothesis, blocks of laterite collected in the area were crushed to simulate texture observed in the vegetation patches. Topsoil collected in a preserved ferruginous field near to the extraction area was also used as a substrate in which Eremanthus erythropappus seedlings, a native woody species, were grown. Seedlings were cultivated without fertilizers in these two substrates and also directly over the exposed and uncrushed laterite. The species proved to be very promising for the revegetation, showing a high survival rate in all substrates. Higher annual growth rates and higher final biomass values were observed in topsoil, but the granulometric reduction of laterite doubled plant growth rate in comparison to the exposed laterite. This result was likely due to the increased availability of essential nutrients to plants and to the improvement in physical conditions for root growth and functioning. Moreover, seedling allometry was not altered by the type of substrate, suggesting that the species was highly tolerant to the new substrate conditions, a fundamental characteristic for success of revegetation of bauxite extraction degraded areas. Copyright © 2013 Elsevier Ltd. All rights reserved.

Geochemical variability of natural soils and reclaimed minespoil soils in the San Juan Basin, New Mexico

USGS Publications Warehouse

Gough, L.P.; Severson, R.C.

1981-01-01

An inventory of total-and extractable-element concentrations in soils was made for three areas of the San Juan Basin in New Mexico: (1) the broad area likely to be affected by energy-related development. (2) an area of soils considered to have potential for use as topsoil in mined-land reclamation. and (3) an area of the San Juan coal mine that has been regraded. topsoiled, and revegetated. Maps made of concentrations of 16 elements in area 1 soils show no gradational pattern across the region. Further. these maps do not correspond to those showing geology or soil types. Sodic or saline problems, and a possible but unproven deficiency of zinc available to plants. may make some of the soils in this area undesirable for use as topsoil in mined-land reclamation. Taxonomic great groups of soil in this area cannot be distinguished because each great group tends to have a large within-group variability if compared to the between-group variability. In area 2 the major soils sampled were of the Sheppard. Shiprock. and Doak association. These soils are quite uniform in chemical composition and are not greatly saline or sodic. As in area 1 soils. zinc deficiency may cause a problem in revegetating most of these soils. It is difficult to distinguish soil taxonomic families by using their respective chemical compositions. because of small between-family variability. Topsoil from a reclaimed area of the San Juan mine (area 3) most closely resembles the chemical composition of natural C horizons of soil from area 1. Spoil material that has not been topsoiled is likely to cause sodic-and saline-related problems in revegetation and may cause boron toxicity in plants. Topsoiling has apparently ameliorated these potential problems for plant growth on mine spoil. Total and extractable concentrations for elements and other parameters for each area of the San Juan Basin provide background information for the evaluation of the chemical quality of soils in each area.

Phosphorus and other soil components in a dairy effluent sprayfield within the central Florida Ridge.

PubMed

Woodard, Kenneth R; Sollenberger, Lynn E; Sweat, Lewin A; Graetz, Donald A; Nair, Vimala D; Rymph, Stuart J; Walker, Leighton; Joo, Yongsung

2007-01-01

There is concern that P from dairy effluent sprayfields will leach into groundwater beneath Suwannee River basins in northern Florida. Our purpose was to describe the effects of dairy effluent irrigation on the movement of soil P and other nutrients within the upper soil profile of a sprayfield over three 12-mo cycles (April 1998-March 2001). Effluent P rates of 70, 110, and 165 kg ha(-1) cycle(-1) were applied to forages that were grown year-round. The soil is a deep, excessively drained sand (thermic, uncoated Typic Quartzipsamment). Mean P concentration in soil water below the rooting zone (152-cm depth) was < or = 0.1 mg L(-1) during 11 3-mo periods. Mehlich-1-extractable (M1) P, Al, and Ca in the topsoil increased over time but did not change in subsoil depths of 25 to 51, 51 to 71, 71 to 97, and 97 to 122 cm. Topsoil Ca increased as effluent rate increased. High Ca levels were found in dairy effluent (avg.: 305 mg L(-1)) and supplemental irrigation water (avg.: 145 mg L(-1)) which likely played a role in retaining P in the topsoil. An effect of effluent rate on P and Al concentrations in the topsoil was not detected, probably due to large and variable quantities present at project initiation. The P retention capacity (i.e., Al plus Fe) increased in the topsoil because Al increased. Dairy effluent contained Al (avg.: 31 mg L(-1)). Phosphorus saturation ratio (PSR) increased over time in the topsoil but not in subsoil layers. Regardless of effluent rate, the P retention capacity and PSR of subsoil, which contained 119 to 229 mg kg(-1) of Al, should be taken into account when assessing the risk of P moving below the rooting zone of most forage crops.

Comparing REE distribution in GEMAS agricultural soils and FOREGS topsoils-subsoils in Italy and Sweden

NASA Astrophysics Data System (ADS)

Petrosino, Paola; Sadeghi, Martiya; Andersson, Madelen; Albanese, Stefano; Dinelli, Enrico; Valera, Paolo; Ladenberger, Anna; Morris, George; Uhlbäck, Jo; Lima, Annamaria; De Vivo, Benedetto

2014-05-01

Scientific interest on Rare Earth Elements (REEs)-bearing media is increasing as a consequence of the rapidly growing demand of these important chemical resources, which are currently used in a large number of technical applications. In this study, Italian and Swedish REE data from the FOREGS database on topsoil and subsoils samples have been compared to the distribution of REEs in the GEMAS samples of agricultural soil (Ap), pertaining to regularly ploughed land to a depth of 20 cm. Principal Component Analysis (PCA) was carried out to identify patterns within both data sets. Investigation of the spatial distribution of REEs in FOREGS topsoil-subsoil and GEMAS Ap media for both countries revealed the prominent role of the geogenic component in the general REE geochemical pattern of the three solid media. Despite a similar REE content in the underlying parent material or bedrocks (alkaline igneous rocks, both intrusive and effusive in Italy, alkaline granites and pegmatites in Sweden), several distinct differences emerged between the two countries driven by climate, topography, age of the rock units and sediments, presence of mineralisations, type of soils and presence of glacial deposits. GEMAS agricultural soils form both countries show higher REEs contents than the corresponding subsoils and topsoils, which could be ascribed to the analytical method specifically set for REEs and the last generation ICP-MS instrument used by SGS Lab to analyze REEs in Ap soils. The REE content in Italian topsoil and subsoil is similar and there is a good agreement between the topsoils and Ap soils, which were collected from similar depth. Swedish subsoil is on the contrary more enriched in REEs with respect to topsoil, and Ap soils even display REE contents higher than subsoils. This anomalous REE concentrations in agricultural soil may originate from the fact that most of the arable land in Sweden has been located on glacial and postglacial deposits, rich in clay which has tendency to accumulate secondary REEs. We concluded that the fingerprints of anthropic activity due to agricultural activities does not influence the geogenic signal. Both in Italy and Sweden, in fact, REE trends in GEMAS agricultural soils are well comparable with those obtained for FOREGS soils sampled from unoccupied and undisturbed regions.

Subsoil carbon accumulation on an arable Mollisol is retention dominated, in contrast to input driven carbon dynamics in topsoil

NASA Astrophysics Data System (ADS)

Beem-Miller, Jeffrey; Lehmann, Johannes

2017-04-01

The majority of the world's soil organic carbon (OC) stock is stored below 30 cm in depth, yet sampling for soil OC assessment rarely goes below 30 cm. Recent studies suggest that subsoil OC is distinct from topsoil OC in quantity and quality: subsoil OC concentrations are typically much lower and turnover times are much longer, but the mechanisms involved in retention and input of OC to the subsoil are not well understood. Improving our understanding of subsoil OC is essential for balancing the global carbon budget and confronting the challenge of global climate change. This study was undertaken to assess the relationship between OC stock and potential drivers of OC dynamics, including both soil properties and environmental covariates, in topsoil (0 to 30 cm) versus subsoil (30 to 75 cm). The performance of commonly used depth functions in predicting OC stock from 0 to 75 cm was also assessed. Depth functions are a useful tool for extrapolating OC stock below the depth of sampling, but may poorly model "hot spots" of OC accumulation, and be inadequate for modelling the distinct dynamics of topsoil and subsoil OC when applied with a single functional form. We collected two hundred soil cores on an arable Mollisol, sectioned into five depth increments (0-10, 10-20, 20-30, 30-50, and 50-75 cm), and performed the following analyses on each depth increment: concentration of OC, inorganic C, permanganate oxidizable carbon (POXC), and total N, as well as texture, pH, and bulk density; a digital elevation model was used to calculate elevation, slope, curvature, and soil topographic wetness index. We found that topsoil OC stocks were significantly correlated (p < 0.05) with terrain variables, texture, and pH, while subsoil OC stock was only significantly correlated with topsoil OC stock and soil pH. Total OC stock was highly spatially variable, and the relationship between surface soil properties, terrain variables, and subsoil OC stock was spatially variable as well. Hot spots of subsoil OC accumulation were correlated with higher pH (> 7.0), flat topography, a high OC to total N ratio, and a high ratio of POXC to OC. These findings suggest that at this site, topsoil OC stock is input driven, while OC accumulation in the subsoil is retention dominated. Accordingly, a new depth function is proposed that uses a linear relationship to model OC stock in topsoil and a power function to model OC stock in the subsoil. The combined depth function performed better than did negative exponential, power, and linear functions alone.

Applying soil science for restoration of post mining degraded landscapes in semi-arid Australia: challenges and opportunities

NASA Astrophysics Data System (ADS)

Muñoz-Rojas, Miriam; Martini, Dylan; Erickson, Todd; Merritt, David; Dixon, Kingsley

2015-04-01

Introduction Current challenges in ecological restoration of post mining environments include the deficit of original topsoil which is frequently lost or damaged, and the lack of soil forming materials. A comprehensive knowledge of soil properties and processes and an adequate management of soil resources are critical to improve the restoration success of these degraded areas. In particular, understanding soil physical, chemical and biological parameters is decisive in environments where water is a limiting factor for seedling establishment and plant survival. To improve the restoration success of biodiverse semi-arid areas disturbed by mining activities (Pilbara region, Western Australia), we conducted experiments to (i) analyse changes in soil physico-chemical properties and soil microbial activity of topsoil stockpiles to optimise its handling and minimise deterioration of nutrients and soil biota, (ii) test climate effects on seedling emergence of native plant species and (iii) assess the potential of mine waste materials as a suitable growth medium for seedling emergence of native plant species under various water regimes. Methods The experimental studies were conducted in controlled environment facilities where air temperature, relative humidity and soil moisture were monitored routinely. Watering regimes were selected to represent rainfall patterns of the area. As a growth media we used material obtained from topsoil stockpiles and waste materials from an active mine site, which were mixed at different ratios. Samples were collected from different parts of the topsoil stockpiles and analysed to determine physical, chemical and biological properties. Results No large discrepancies in physical and chemical values were detected at different positions of the stockpiles. However, microbial activity was highly variable, particularly inside the stockpiles. Seedling emergence on topsoil growth media was highly dependent on climate factors with emergence rates varying significantly (P< 0.001) across species. Highest emergence rates were obtained for Acacia adoxa and Grevillea pyramidalis in the 30°C scenario and adequate soil moisture levels (mean % ± SE 71±5.3 and 80±3.8 respectively). With available water, emergence was above 30% for all species and growth media types (topsoil, waste and mixes of topsoil and waste at 50:50 and 25:75 ratios). However, under drought conditions, emergence severely decreased for all species. In particular, Gossypium robinsonii and Grevillea pyramidalis did not show any response with less than 50% of topsoil in the composition of growth media. Our results suggest that changes in precipitation regimes can have a critical effect on seedling emergence of native plant species from the Pilbara. Understanding soil physico-chemical properties of soil materials and changes in soil moisture related to rainfall patterns and growth media blends are crucial to predict the success of seedling emergence and ultimately achieve biodiverse restoration in semiarid areas. This research is part of a broader multi-study approach, the Restoration Seedbank Initiative project, a partnership between The University of Western Australia, BHP Billiton Iron Ore, and Kings Park and Botanic Garden. Keywords Pilbara region, biodiverse ecosystems, soil microbial activity, topsoil stockpile, dry environments, land rehabilitation.

A Qualitative Experiment to Analyze Microbial Activity in Topsoil Using Paper and a Handmade Reflection Photometer

ERIC Educational Resources Information Center

Agbeko, Julius Kofi; Kita, Masakazu

2007-01-01

This article describes a novel, hands-on method to qualitatively determine the extent of microbial activity in topsoil using ordinary blank paper. Appropriate and scalable for the high school and college level, these experiments expose students to some of the challenges facing environmental researchers and also contribute to curriculum development…

Using topsoil thickness to improve site-specific phosphorus and potassium management on claypan soil

USDA-ARS?s Scientific Manuscript database

Precise P and K fertilizer management on claypan soils can be difficult due to variable topsoil thickness, or depth to claypan (DTC), across landscapes, nutrient supply from subsoils, and crop removal. Therefore, a study was performed to determine if DTC could be used to improve P and K management f...

Effect of redistributing windrowed topsoil on growth and development of ponderosa pine plantations

Treesearch

Jianwei Zhang; David H. Young; Kenneth R. Luckow

2015-01-01

Windrowing site preparation often displaces significant amounts of topsoil including nutrients and carbon into the strip-piles. Although short-term growth may increase due to the early control of competing vegetation, this practice can reduce long-term plantation productivity. Here, we report an experiment established in 1989 in a 28-year-old ponderosa pine (

Fertilizer and Mulch Improves Yellow-Poplar Growth on Exposed harsells Subsoils

Treesearch

John K. Francis

1977-01-01

Fertilizing and mulching of eroded Hartsells soil increased height and diameter of yellow-poplars. To see if chemical infertility of exposed Hartsells subsoils limits yellow-poplar growth and to test fertilizer and mulch as remedial agents, seedlings were planted on undisturbed soil, soil with the topsoil removed, and soil with the topsoil removed but mulched with leaf...

Responses of soil biota to organic amendments in stripmine spoils in Northwestern New Mexico

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elkins, N.Z.; Parker, L.W.; Aldon, E.

The effects of organic amendments and topsoiling on the soil biota and decomposition were examined in order to evaluate the relative efficacy of the amendments in restarting soil processes. Decomposition of barley straw (Hordeum vulgare) and populations of soil biota on strip coal-mine spoils in northwestern New Mexico were studied. The spoils had been amended with straw mulch, bark, topsoil, or no organic additives. Decomposition rates were highest in the unmined area and the bark, amended spoils, and lowest on the topsoil amendment and unamended spoil. Few differences were observed in the populations of soil microflora. Where differences were observed,more » the bark-amended spoils had the highest populations and biomass. Soil microflora activity, as indicated by decomposition rates, was enhanced by bark amendment. Soil microfaunal populations were highest on the bark-amended spoils and unmined soil. Important soil mites (soil Acari), the oribatids, were found only in the bark-amended spoils and the unmined soils. These studies suggest that addition of selected organic amendments (bark) to mine spoils may be as effective in developing a soil as the more expensive topsoil/mulch procedures currently used in reclamation procedures. 25 references.« less

Petroleum hydrocarbon pollution of urban topsoil in Ibadan city, Nigeria

DOE Office of Scientific and Technical Information (OSTI.GOV)

Onianwa, P.C.

The distribution of total petroleum hydrocarbon in topsoils from various parts of Ibadan city, Nigeria, was studied. Samples were selected from around the following zones: (a) railway tracks, (b) petrol stations, (c) refuse dumps, (d) residential areas, (e) high traffic density areas, (f) mechanical workshops, and (g) control zones. Contamination of the topsoil with hydrocarbons was significant only around petrol stations and mechanical workshops where the factors of accumulation were 10.1 and 4.72, respectively. The general trend in hydrocarbon levels was petrol station > mechanical workshop > refuse dumps > high traffic areas {ge} rail tracks > control residential areas.more » The results highlight the need to monitor urban environments that are remote from petroleum exploration activities for petroleum hydrocarbon contamination. 19 refs., 3 tabs.« less

Does DOM properties or the amount of DOC induces iron reduction in topsoil porewater?

NASA Astrophysics Data System (ADS)

Szalai, Zoltán; Ringer, Marianna; Kiss, Klaudia; Perényi, Katalin; Jakab, Gergely

2017-04-01

Iron content of porewater in hydromorphic soils shows high temporal variability. This usually correlates with dissolved organic carbon (DOC) content, but the correlation can be weak in some cases. Some studies suggest that ferrous iron stabilizes organic carbon in dissolved state. On the contrary, other papers report about dissolved iron stabilization by dissolved organic matter (DOM). Present study focuses on this apparent contradiction and on the interaction of organic carbon and iron in hydromorphic soils. Studied gleyic Phaeozems (3 profiles) and mollic Gleysols (3 profiles) are located in Geresdi-dombság (Hungary) and in Danube-Tisza Interfluve (Hungary) respectively. Dynamics of porewater pH, EH, have been recorded by field stations at 20, 40 and 100 cm depth during the growing season with 10 min temporal resolution. Porewater occasionally have also been sampled in each depth. The presence of ferrous iron was detected by dipyridil field test. DOC, dissolved nitrogen (DN) and iron were measured by TOC analyser and fl-AAS. Molecular size and molecular weight were measured by photon correlation spectroscope (DLS and SLS). Textural and mineralogical properties of studied soils were also determined. Relationships among studied parameters were tested by Spearman's rank correlation. The seasonal dynamics of redox potential is primarily controlled by saturation, but spatial differences are also driven by vegetation. The environment is usually reductive for iron oxides between March and July, but intensive daily redox fluctuations could be measured in June and July in some topsoils. Short term temporal variability of redox conditions is depended on the physiological activity of plants. Most of the papers published a range between +100 and +50 mV for iron reduction in aquatic systems. Topsoil porewater measurements show three redox ranges where concentration of dissolved iron has been increased: +320 to +200, +80 to +20 and below-160 mV. These ranges were identified independently from each other in various topsoils and subsoils. DOC was correlated with dissolved iron only in the most oxidative topsoils. Therefore we did not find correlation between DOC and dissolved iron in the studied topsoils of Gleysols. Molecular size and molecular weight of DOM have correlated with dissolved iron in all topsoils. We did not find any relationship between dissolved iron and any other properties at 100 cm depth. Presence of colour reaction and the colour intensity of dipyridil test also did not show correlation with measured dissolved iron in all studied topsoils. High ratio of dithionite and oxalate extractable iron of the solid phase and the molecular size measurements suggest that this observation can be explained by an intensive complex formation of ferric iron with low molecular size DOM. This research was supported by Hungarian Scientific Research Fund (OTKA K100180) and Gergely Jakab was supported by János Bolyai Fellowship of the MTA.

Water Redistribution, Temperature Change and CO2 Diffusion of Reconstruction Soil Profiles Filled with Gangue in Coal Mining Areas

NASA Astrophysics Data System (ADS)

Wang, S.; Zhan, H.; Chen, X.; Hu, Y.

2017-12-01

There were a great many projects of reconstruction soil profile filled with gangue to restore ecological environment and land resources in coal mining areas. A simulation experimental system in laboratory was designed for studying water transport and gas-heat diffusion of the reconstruction soil as to help the process of engineering and soil-ripening technology application. The system could be used for constantly measuring soil content, temperature and soil CO2 concentration by laid sensors and detectors in different depth of soil column. The results showed that soil water infiltration process was slowed down and the water-holding capacity of the upper soil was increased because of good water resistance from coal gangue layer. However, the water content of coal gangue layer, 10% approximately, was significantly lower than that of topsoil for the poor water-holding capacity of gangue. The temperature of coal gangue layer was also greater than that of soil layer and became easily sustainable temperature gradient under the condition with heating in reconstruction soil due to the higher thermal diffusivity from gangue, especially being plenty of temperature difference between gangue and soil layers. The effects of heated from below on topsoil was small, which it was mainly influenced from indoor temperature in the short run. In addition, the temperature changing curve of topsoil is similar with the temperature of laboratory and its biggest fluctuation range was for 2.89°. The effects of aerating CO2 from column bottom on CO2 concentration of topsoil soil was also very small, because gas transport from coal gangue layers to soil ones would easily be cut off as so to gas accumulated below the soil layer. The coal gangue could have a negative impact on microbial living environment to adjacent topsoil layers and declined microorganism activities. The effects of coal gangue on topsoil layer were brought down when the cove soil thickness was at 60 cm. And the influences gradually would be weakened with the thickness increasing.

Contamination and health risks of soil heavy metals around a lead/zinc smelter in southwestern China.

PubMed

Li, Peizhong; Lin, Chunye; Cheng, Hongguang; Duan, Xiaoli; Lei, Kai

2015-03-01

Anthropogenic emissions of toxic metals from smelters are a global problem. The objective of this study was to investigate the distribution of toxic metals in soils around a 60 year-old Pb/Zn smelter in a town in Yunnan Province of China. Topsoil and soil core samples were collected and analyzed to determine the concentrations of various forms of toxic metals. The results indicated that approximately 60 years of Pb/Zn smelting has led to significant contamination of the local soil by Zn, Pb, Cd, As, Sb, and Hg, which exhibited maximum concentrations of 8078, 2485, 75.4, 71.7, 25.3, and 2.58mgkg(-1), dry wet, respectively. Other metals, including Co, Cr, Cu, Mn, Ni, Sc, and V, were found to originate from geogenic sources. The concentrations of smelter driven metals in topsoil decreased with increasing distance from the smelter. The main contamination by Pb, Zn, and Cd was found in the upper 40cm of soil around the Pb/Zn smelter, but traces of Pb, Zn, and Cd contamination were found below 100cm. Geogenic Ni in the topsoil was mostly bound in the residual fraction (RES), whereas anthropogenic Cd, Pb, and Zn were mostly associated with non-RES fractions. Therefore, the smelting emissions increased not only the concentrations of Cd, Pb, and Zn in the topsoil but also their mobility and bioavailability. The hazard quotient and hazard index showed that the topsoil may pose a health risk to children, primarily due to the high Pb and As contents of the soil. Copyright © 2014 Elsevier Inc. All rights reserved.

Germination and emergence of annual species and burial depth: Implications for restoration ecology

NASA Astrophysics Data System (ADS)

Limón, Ángeles; Peco, Begoña

2016-02-01

Due to the high content of viable seeds, topsoil is usually spread on ground left bare during railway and motorway construction to facilitate the regeneration of vegetation cover. However, during handling of the topsoil, seeds are often buried deeply and they cannot germinate or the seedlings cannot emerge from depth. This study experimentally explores the predictive value of seed mass for seed germination, mortality and seedling emergence at different burial depths for 13 common annual species in semiarid Mediterranean environments. We separate the effect of burial depth on germination and emergence by means of two experiments. In the germination experiment, five replicates of 20 seeds for each species were buried at depths ranging from 0 to 4 cm under greenhouse conditions. Germinated and empty or rotten seeds were counted after 8 weeks. In the emergence experiment, five replicates of four newly-germinated seeds per species were buried at the same depths under controlled conditions and emergence was recorded after 3 weeks. The effect of burial depth on percentage of germination and seedling emergence was dependent on seed size. Although all species showed a decrease in germination with burial depth, this decrease was greater for small-than large-seeded species. Percentage of emergence was positively related to seed mass but negatively related to burial depth. Seed mortality was higher for small-than large-seeded species, but there was no general effect of burial depth on this variable. Thus, the current practice of spreading 30 cm deep layers of topsoil in post-construction restoration projects is unadvisable. In this restoration scenario, thinner layers of topsoil should be used to achieve the maximum potential of the topsoil for germination and seedling establishment.

[Practice of engineering management and its effect on schistosomiasis control in Hankou marshland, Wuhan City].

PubMed

Zhi-Qing, Deng; Xiao-Dong, Tan; Shi-Bo, Kong; Kai, Wu; Ming-Xing, Xu; Hua-Tang, Luo

2017-01-06

To investigate the Oncomelania hupensis snail control effect of schistosomiasis control engineering in marshland within Wuhan City. The engineering measures including surface barrier removal, molluscicide, flatting surface, topsoil stripping, topsoil covering and ditch renovation were applied to transform Hankou marshland. Then the corresponding technical parameters of engineering measures were put forward. The situation of snails was analyzed before and after the transform project. The total length and area of the project were 6 015 m and 87.21 hm 2 , respectively, including 17.44 hm 2 of topsoil landfill, 52.08 hm 2 of topsoil covering and 23 new ditches. After the transformation, the average length of the new groove, the groove top width, groove depth, height difference, and the average values of slopes and ditch bottom slope were all increased, while the average values of the width and height of the ditch were decreased. At the same time, the marshland beach surface had a new slope that the embankment was higher than the river and no living O. hupensis snails were found then. The snail breeding environment in Hankou marshland has been effectively changed by the project. However, the constant monitoring and engineering management are still needed to consolidate the effect.

[Correlativity study of the distribution of soil magnetic susceptibility and the heavy metal contents in Xi'an City].

PubMed

Chen, Xiu-Duan; Lu, Xin-Wei; Yang, Guang

2013-03-01

The magnetic susceptibility and the concentrations of Co, Cr, Cu, Pb, Sn, Sr and Ba in topsoil samples from Xi'an City were measured to study their spatial distribution and their correlation in this study. The results show that the concentrations of all measured heavy metals are higher than their background values in Cinnamon topsoil, which is the main soil type of Xi'an City. The heavy metals concentrations and the magnetic susceptibility of the studied samples display moderate variance. Co, Cr, Cu, Pb, Sn, Sr and Ba are significantly positively correlated with low-frequency magnetic susceptibility, while are significantly negatively correlated with frequency susceptibility. The spatial distribution of low-frequency magnetic susceptibility is identical with the concentrations of Pb and Cu. However, the spatial variation of frequency magnetic susceptibility is different from the concentrations of Co, Cr and Ba. The pollution assessment results show that the heavy metal pollution in topsoil of Xi'an City is moderate. The spatial contribution of the pollution load index was significantly correlated with the magnetic susceptibility of topsoil in Xi'an City. Therefore, soil magnetic susceptibility can be used as an effective monitoring means for heavy metal pollution in urban soil.

PAH contamination in Beijing’s topsoil: A unique indicator of the megacity’s evolving energy consumption and overall environmental quality

PubMed Central

Li, Jinguo; Zheng, Yi; Luo, Xiaolin; Lin, Zhongrong; Zhang, Wei; Wang, Xuejun

2016-01-01

To improve its air quality, Beijing, the capital of China, has implemented high-cost pollution control measures mainly focused on shifting its energy mix. However, the effectiveness of these measures has long been questioned, especially given the recent problem of severe haze. The main study objectives are to achieve independent, although indirect, information on Beijing’s air pollution by measuring the level of polycyclic aromatic hydrocarbon (PAH) contamination in topsoil and to examine how soil contamination reflects energy consumption. Soil sampling data from two years, 2004 and 2013, were used. The key findings are as follows: 1) although the total PAH content in the topsoil did not significantly decrease from 2004 to 2013, the composition changed considerably; 2) as of 2013, vehicle emissions replaced coal combustion as the leading source of soil PAHs, which validates the existing policy measures regarding vehicle purchasing and traffic volume; 3) the regional transport of atmospheric pollutants, as indicated by the contribution of coking sources in 2013, is not negligible; and 4) appropriate policy measures are needed to control the growing practice of burning biomass. Overall, this study demonstrates that the PAH contamination in topsoil represents an informative indicator of Beijing’s energy consumption and overall environmental quality. PMID:27633056

Extreme anthropogenic erosion: Topsoil Selling in the Mekong Delta and consequences for soil quality

NASA Astrophysics Data System (ADS)

Weigand, Susanne; Sebesvari, Zita; Vien, Duong Minh; Kruse, Jens; Guong, Vo Thi; Amelung, Wulf

2017-04-01

Increasing urbanization and industrialization leads to increasing demands for construction material, especially in low income countries. For this purpose topsoil is sometimes removed and used as construction material. Topsoil Selling is practiced around the world from America, Europe and Africa to Asia. In the Mekong Delta, Vietnam farmers physically remove the upper 10-40 cm of their paddy fields and sell it to contractors (= Topsoil Selling, TSS). The excavated material is used for road construction or brick production and therefore the most fertile part of the paddy soil is irrecoverably lost. The temporal effects of topsoil removal on soil quality are not yet fully understood. We hypothesized that after soil removal, soil quality and yield potential are significantly lower compared to the original topsoil. To test this hypothesis, we sampled two chronosequences in two different provinces of the Mekong Delta. The provinces are Sóc Trăng (Control, 1, 2, 3, 8 years after TSS) and Trà Vinh (Control, 3, 5, 8 years after TSS). The sampling areas differ in texture and cultivation practice: clayey-loamy vs. sandy-loamy and double vs. triple rice cropping. For each year of the chronosequence, 4 field sites were investigated. We sampled the Ap, Bg1, and Bg2 horizon up to 40 cm depth as composite samples from 6 to 8 cores per field. Soil organic carbon (Corg) stocks at TSS sites were up to 20 t/ha lower than at Control sites (Control: 50 t/ha) in Sóc Trăng and up to 15 t/ha lower in Tra Vinh (Control: 30 t/ha). Especially the Bg horizons revealed a continuous decline in Corg with time after soil removal. Analysis of available nutrients (Na, K, Ca, Mg, S, Fe, Al, Mn, Zn, Cu) determined by the Mehlich3-Method are still ongoing. Preliminary results, however, suggest that there is not sustainable loss of these elements after selling, but that initial risk of losses are reverted under prolonged management. Phosphorus fractionation according to the Hedley method indicate, however, that easily and moderately plant available P forms are depleted, which has to be accounted for in land-restoration measures. Overall, the current data we received so far revealed that TSS induces mainly a dramatic loss of soil organic matter. It was ongoing up to the 8th year of our chronosequence; yet, it was not necessarily accompanied by losses in inorganic nutrients. As a result, there is a chance also for the farmers to overcome risks in yield decline because the former subsoils overtake the role of the former topsoils in maintaining rice production.

Comparison on humus and soil geochemical baselines in Southern Finland

NASA Astrophysics Data System (ADS)

Minolfi, Giulia; Tarvainen, Timo; Jarva, Jaana

2016-04-01

Humus has been recognized since a survey in 1977 (Allen and Steinnes, 1980) as one of the best sampling media for mapping regional environmental contamination because of the strong geochemical contrast between anomalous and background concentrations resulting from its capacity to accumulate high levels of trace metals. This study is in the framework of the comparison between humus, topsoil and moss deposition data, in order to analyze the humus behavior and to find possible similarities to underlying geology and long-range atmospheric deposition. The analyzed samples are part of a geochemical mapping programme carried out by the Geological Survey of Finland (GTK); subsoil, topsoil and humus samples have been collected in a large area in Southern Finland since 2002. 816 sample pairs (humus and topsoil samples) were selected for statistical analysis. Statistical graphs, like histograms, CP plots and box plots, were realized for 31 elements, and showed that most of the elements have completely different distribution of concentrations in humus and in topsoil samples. Then the correlation between the element concentrations in humus and minerogenic topsoil has been evaluated measuring the Spearman rank correlation value and elaborating scatter plots between the element concentrations in humus and minerogenic topsoil, and between the content of the element vs. the content of organic C. The concentrations of some elements, like K, Mg, Fe, Al, in humus samples are controlled by the content of mineral matter, derived by the soil dust. Other elements, such as As, Bi, Cd, Co, Cu, Mn, Mo, Ni, Pb, Rb, Th, V and Zn showed evident outliers, with probable anthropogenic origin. In order to explain these anomalous high values in humus, the geographic distributions of these elements in humus and topsoil were analyzed and then compared to the deposition data obtained by the national moss data. High values appear in areas where the anthropogenic impact is strong, like the Harjavalta area, where older emissions from the smelter still cause anomaly patterns in some elements, and the more densely populated and industrialized areas, like the city of Tampere and the coastline from Porvoo to the capital region of Helsinki. According to the results presented here, the humus concentrations are more affected by the atmospheric impact than by the lithogenic contributes. Because of the great anthropogenic influence on humus concentrations, that causes locally high anomalies, even after many years, new humus samples should be collected, in order to improve the knowledge about humus behavior and anthropogenic input to the topmost layer of ground surface. REFERENCES Allen, R. O., & Steinnes, E. 1980. Contribution from long-range atmospheric transport to the heavy metal pollution of surface soil. D Drabløs, A Tollan (Eds.), Ecological impact of acid precipitation, SNSF Project, Oslo-Ås (1980), pp. 102-103.

Experimental Studies on Geocells and Mat Systems for Stabilization of Unpaved Shoulders and Temporary Roads

NASA Astrophysics Data System (ADS)

Guo, Jun

Geosynthetics have been used to improve the performance of geomaterials, especially when weak soil exists in roadway applications. In this study, two types of geosynthetic materials, geocell and a mat system, were studied for their applications for unpaved roads and shoulders. The study of geocell was focused on its application for unpaved shoulders. The ability of geocell to improve different geomaterials over intermediate strength subgrade and its possible effect on vegetation were investigated. The study of the mat system was focused on investigating the performance of the mat system over soft and intermediate subgrade with different strengths under cyclic loading to simulate temporary roadway conditions. In the study of geocell for the application for unpaved shoulders, six large scale plate loading tests were conducted on a single type of geocell on target 5% CBR subgrade to investigate the benefits of geocell reinforcement on different base course and topsoil combinations. Different base course and topsoil combinations were investigated including: 200-mm thick unreinforced aggregate, 200-mm thick soil-aggregate mixture (50% aggregate and 50% top soil) with and without geocell reinforcement, 200-mm thick geocell-reinforced topsoil, 50-mm thick aggregate over 150-mm soil-aggregate mixture (50% aggregate and 50% top soil), and 50-mm thick top soil over 150-mm thick geocell-reinforced soil-aggregate mixture (50% aggregate and 50% top soil). Earth pressure cells were install at the interface between subgrade and base course to monitor the load distribution. The cyclic plate loading tests showed that geocell effectively reduced the permanent deformation and the geocell-reinforced soil-aggregate mixture slightly outperformed the unreinforced aggregate at the same thickness. The plate loading tests also suggested the topsoil cover resulted in large permanent deformations. A one-year long outdoor field vegetation test was conducted on base courses with different combinations of aggregate and topsoil including: 200-mm thick unreinforced topsoil, 200-mm thick soil-aggregate mixture (50% aggregate and 50% topsoil), 50-mm thick aggregate over 150-mm soil-aggregate mixture (50% aggregate and 50% topsoil), and 50-mm thick topsoil over 150-mm reinforced soil-aggregate mixture (50% aggregate and 50% topsoil) to investigate the possible effect of geocell on shoulder vegetation established mainly by tall fescue grass and perennial ryegrass. One control (unreinforced) section and one geocell-reinforced section were prepared for each base course combination with a surface area of 1.5 m by 1.5 m. During the one-year test period, soil moisture temperature and volumetric moisture content were monitored. Weather data, such as precipitation and air temperature, were obtain from the nearby weather station at the Lawrence airport. Vegetation growth was evaluated by grass leaf blade length, root length, and grass density. Vegetation biomass was obtained at the end of the test. The test results showed no definite evidence of geocell influencing the vegetation in unpaved shoulders. In the study of the mat system, six large-scale cyclic plate loading tests were conducted on a single type of polyethylene mat system with anchorage to study its performance over soft and intermediate subgrade with the CBR ranging from 1% to 4%. For the comparison purposes, test sections with and without the mat system were prepared and evaluated. For the test section with 1% CBR subgrade, an aggregate base course was used for the test section without the mat system to enable the cyclic plate loading test. The size of the mat system under the investigation was 1.92 m by 1.92 m. A cyclic load at the magnitude of 40 kN was applied through a 300 mm diameter loading plate with a thin rubber pad to simulate a vehicle tire. Earth pressure cells were installed at the interface between the mat system and the subgrade to monitor the load distribution. Loading plate displacements were measured by the displacement transducer inside the actuator. Test results concluded that the mat system was more effective over the intermediate subgrade than the soft subgrade and when large permanent deformations were allowed.

Effects of Rainfall-Induced Topsoil Structure Changes on Root-Zone Moisture Regime during the Dry Period

NASA Astrophysics Data System (ADS)

Wang, Feng; Chen, Jiazhou; Lin, Lirong

2018-01-01

Rainfall erosion and subsequent intermittent drought are serious barriers for agricultural production in the subtropical red soil region of China. Although it is widely recognized that rainfall-induced soil structure degradation reduced soil water storage and water-holding capacity, the effects of variation of the rainfall-induced topsoil structure on the subsequent soil water regime during the dry period is still rarely considered. The objective of this study was to ascertain the way of rainfall-induced topsoil structure changes on the subsequent soil water regime during the dry period. In a three-year-long experiment, six practices (CK, only crop; SM, straw mulching; PAM, polyacrylamide surface application; B, contour Bahia-grass strip; SPAM, straw mulching and polyacrylamide surface application; and BPAM, contour Bahia-grass strip and polyacrylamide surface application) were conducted at an 8° farmland with planting summer maize resulting in different topsoil structure and root-zone moisture, to establish and reveal the quantitatively relationship between the factors of topsoil structure and soil drought. Rainfall erosion significantly increased the soil crust coverage, and decreased the WSA 0.25, 0-30 mm soil porosity and mean pore size. There was no significant difference during the raining stage of root-zone water storage between CK and other practices. An index of soil drought intensity ( I) and degree ( D) was established using soil water loss rate and soil drought severity. The larger value of I means a higher rate of water loss. The larger value of D means more severe drought. During the dry period, I and D were significantly higher in CK than in other practices. I and D had significantly positively correlation with the crust size and crust coverage, and negatively with WSA 0.25, 15-30 mm soil porosity and mean pore size. Among of soil structure factors, the soil porosity had the largest effect on I and D. The rainfall-induced topsoil structure changes greatly deteriorated the root-zone regime during the dry period mainly due to significant increasing soil water loss but little improving the raining stage of soil water storage. Straw mulching had greater effects than other practices in alleviating rainfall-induced erosion and intermittent drought, and could be a better strategy applied for this region.

The spatial extent of agriculturally-induced topsoil removal in the Midwestern United States

NASA Astrophysics Data System (ADS)

Thaler, E.; Larsen, I. J.; Yu, Q.; Keiluweit, M.

2017-12-01

Human-induced erosion of soil organic carbon (SOC) degrades soils, leading to decreased crop yields. Here we develop a novel approach for mapping the spatial distribution of complete topsoil loss in agricultural landscapes, focusing on the Midwestern U.S. We used the ferric iron index (FeI) derived from high-resolution satellite imagery to map Fe-rich subsoil exposed by the loss of carbon-rich topsoil. Integrating topographic curvature derived from high resolution topographic data with FeI values demonstrates that FeI values are lowest in concave hollows where eroded soil accumulates, and increase linearly with topographic curvature on convex hilltops. The relationship between FeI and curvature indicates diffusion-like erosion by tillage is a dominant mechanism of soil loss, a mechanism generally not included in soil loss prediction in the U.S. Moreover, the FeI and curvature data indicate SOC-rich topsoil has been completely removed from hilltops, exposing Fe-rich subsoil. This interpretation supported by measurements of FeI using laboratory spectra, extractable-Fe, and organic C from two soil profiles from native prairies, which preserve the pre-agricultural soil profile. FeI increased sharply from the topsoil through the subsoil and total C and extractable Fe content are negatively correlated in both profiles. We calculated topographic curvature for 3.8 x105 km2 of the formerly-glaciated Midwestern U.S. using LiDAR data and found that convex topography, where FeI values suggest topsoil has been completely stripped, covers half of the landscape. Assuming complete removal of original SOC on all hilltops, we estimate that 784 Tg of C has been removed since cultivation began in the mid-1800s and that the SOC decline results in billions of dollars in annual economic losses from decreased crop yields. Restoration of eroded SOC has been proposed as a method to sequester atmospheric CO2 while simultaneously increasing crop yields, and our estimates suggest that replenishing eroded SOC within the Midwestern U.S. to pre-settlement levels could sequester 2900 Tg of CO2, equivalent to more than half of 2016 U.S. CO2 emissions. Our study highlights both the necessity to incorporate tillage into soil erosion models and the potential for SOC restoration to increase crop yields and offset carbon emissions.

Identification and mapping of heavy metal pollution in soils of a sports ground in Galway City, Ireland, using a portable XRF analyser and GIS.

PubMed

Carr, Ramona; Zhang, Chaosheng; Moles, Norman; Harder, Marie

2008-02-01

Heavy metals in urban soils continue to attract attention because of their potential long-term effects on human health. During a previous investigation of urban soils in Galway City, Ireland, a pollution hotspot of Pb, Cu, Zn and As was identified in the sports ground of South Park in the Claddagh. The sports ground was formerly a rubbish dumping site for both municipal and industrial wastes. In the present study, a portable X-ray fluorescence (PXRF) analyser was used to obtain rapid in-situ elemental analyses of the topsoil (depth: about 5-10 cm) at 200 locations on a 20 x 20-m grid in South Park. Extremely high values of the pollutants were found, with maximum values of Pb, Zn, Cu and As of 10,297, 24,716, 2224 and 744 mg/kg soil, respectively. High values occur particularly where the topsoil cover is thin, whereas lower values were found in areas where imported topsoil covers the polluted substrate. Geographic Information Systems (GIS) techniques were applied to the dataset to create elemental spatial distribution maps, three-dimensional images and interpretive hazard maps of the pollutants in the study area. Immediate action to remediate the contaminated topsoil is recommended to safeguard the health of children who play at the sports ground.

Glyphosate and AMPA of agricultural soil, surface water, groundwater and sediments in areas prevalent with chronic kidney disease of unknown etiology, Sri Lanka.

PubMed

Gunarathna, Shankani; Gunawardana, Buddhika; Jayaweera, Mahesh; Manatunge, Jagath; Zoysa, Kasun

2018-06-08

Glyphosate, which is commercially available as Roundup®, was the widely used herbicide in Sri Lanka until 2015 and is suspected to be one of the causal factors for Chronic Kidney Disease of unknown etiology (CKDu). This research, therefore, aims at studying the presence of glyphosate and Aminomethylphosphonic acid (AMPA) in different environmental matrices in CKDu prevalent areas. Topsoil samples from agricultural fields, water samples from nearby shallow wells and lakes, and sediment samples from lakes were collected and analyzed for glyphosate and AMPA using the LC/MS. Glyphosate (270-690 µg/kg) and AMPA (2-8 µg/kg) were detected in all soil samples. Amorphous iron oxides and organic matter content of topsoil showed a strong and a moderate positive linear relationship with glyphosate. The glyphosate and inorganic phosphate levels in topsoil had a strong negative significant linear relationship. Presence of high valence cations such as Fe 3+ and Al 3+ in topsoil resulted in the formation of glyphosate-metal complexes, thus strong retention of glyphosate in soil. Lower levels of AMPA than the corresponding glyphosate levels in topsoil could be attributed to factors such as the strong adsorption capacity of glyphosate to soil and higher LOQ in the quantification of AMPA. The glyphosate levels of lakes were between 28 to 45 µg/L; no AMPA was detected. While trace levels of glyphosate (1-4 µg/L) were detected in all groundwater samples, AMPA (2-11µg/L) was detected only in four out of nine samples. Glyphosate was detected in all sediment samples (85-1000 µg/kg), and a strong linear relationship with the organic matter content was observed. AMPA was detected (1-15 µg/kg) in seven out of nine sediment samples. It could be inferred that the impact on CKDu by the levels of glyphosate and AMPA detected in the study area is marginal when compared with the MCL of the USEPA (700 µg/L).

Post-fire recovery of soil organic matter in a Cambisol from typical Mediterranean forest in Southwestern Spain.

PubMed

Jiménez-González, Marco A; De la Rosa, José María; Jiménez-Morillo, Nicasio T; Almendros, Gonzalo; González-Pérez, José Antonio; Knicker, Heike

2016-12-01

Wildfire is a recurrent phenomenon in Mediterranean ecosystems and contributes to soil degradation and desertification, which are partially caused by alterations to soil organic matter (SOM). The SOM composition from a Cambisol under a Mediterranean forest affected by a wildfire is studied in detail in order to assess soil health status and better understand of soil recovery after the fire event. The soil was sampled one month and twenty-five months after the wildfire. A nearby unburnt site was taken as control soil. Soil rehabilitation actions involving heavy machinery to remove burnt vegetation were conducted sixteen months after the wildfire. Immediately after fire the SOM increased in topsoil due to inputs from charred vegetation, whereas a decrease was observed in the underlying soil layer. Twenty-five months after fire soil-pH increased in fire-affected topsoil due to the presence of ashes, a decrease in SOM content was recorded for the burnt topsoil and similar trend was observed for the water holding capacity. The pyro-chromatograms of burned soils revealed the formation of additional aromatic compounds. The thermal cracking of long-chain n-alkanes was also detected. Solid-state 13 C NMR spectroscopy supported the increase of aromatic compounds in the fire-affected topsoil due to the accumulation of charcoal, whereas the deeper soil sections were not affected by the fire. Two years later, soil parameters for the unburnt and burnt sites showed comparable values. The reduction of the relative intensity in the aromatic C region of the NMR spectra indicated a decrease in the charcoal content of the topsoil. Due to the negligible slope in the sampling site, the loss of charcoal was explained by the post-fire restoration activity, degradation, leaching of pyrogenic SOM into deeper soil horizons or wind erosion. Our results support that in the Mediterranean region, fire-induced alteration of the SOM is not lasting in the long-term. Copyright © 2016 Elsevier B.V. All rights reserved.

Reduction in soil aggregate size distribution due to wind erosion

NASA Astrophysics Data System (ADS)

Swet, Nitzan; Katra, Itzhak

2017-04-01

Soil erosion process by wind causes emission of fine soil particles, and thus alters the topsoil's properties, fertility, and erodibility. Topsoil resistance to erosion depends on its physicochemical properties, especially on the soil aggregation. Although the key role of aggregates in soil erodibility, quantitative information on the relations between soil aggregate size distribution (ASD) and erosion is still lucking. This study focuses on ASD analyses before and after soil erosion by wind. Wind tunnel experiments and soil analyses were conducted on semiarid loess topsoils with different initial conditions of aggregation. The results show that in all initial soil conditions saltation of sand particles caused the breakdown of macro-aggregates > 500 µm, resulting in increase of micro-aggregates (63-250 µm). The micro-aggregate production increases with the wind shear velocity (up to 0.61 m s-1) for soils with available macro-aggregates. The findings highlight dynamics in soil aggregation in response to erosion process, and therefore the significance of ASD in quantifying soil degradation and soil loss potential.

Investigating the Role of Wind in the Dispersion of Heavy Metals Around Mines in Arid Regions (a Case Study from Kushk Pb-Zn Mine, Bafgh, Iran).

PubMed

Mokhtari, Ahmad Reza; Feiznia, Sadat; Jafari, Mohammad; Tavili, Ali; Ghaneei-Bafghi, Mohammad-Javad; Rahmany, Farah; Kerry, Ruth

2018-03-16

The Kushk Pb-Zn mine is located in Central Iran and it has been in operation for the last 75 years. To investigate the role of wind dispersion of heavy metal pollutants from the mine area, dust samples were collected during 1 year and topsoil samples were collected around the mine. Results showed that the topsoil is polluted with Pb and Zn to about 1500 m away from the mine. It was also found that there was not a significant difference between the metal concentrations in topsoil and dust samples. The Pb and Zn concentrations in the dust samples exceeded 200 mg kg -1 and their lateral dispersion via wind was estimated to be about 4 km away from the mine. It has been shown that a combination of mining activities and mechanical dispersion via water and wind have caused lateral movement of heavy metals in this area.

Chemical and Physical Soil Restoration in Mining Areas

NASA Astrophysics Data System (ADS)

Teresinha Gonçalves Bizuti, Denise; de Marchi Soares, Thaís; Roberti Alves de Almeida, Danilo; Sartorio, Simone Daniela; Casagrande, José Carlos; Santin Brancalion, Pedro Henrique

2017-04-01

The current trend of ecological restoration is to address the recovery of degraded areas by ecosystemic way, overcoming the rehabilitation process. In this sense, the topsoil and other complementary techniques in mining areas plays an important role in soil recovery. The aim of this study was to contextualize the soil improvement, with the use of topsoil through chemical and physical attributes, relative to secondary succession areas in restoration, as well as in reference ecosystems (natural forest). Eighteen areas were evaluated, six in forest restoration process, six native forests and six just mining areas. The areas were sampled in the depths of 0-5, 5-10, 10-20, 20-40 and 40-60 cm. Chemical indicators measured were parameters of soil fertility and texture, macroporosity, microporosity, density and total porosity as physical parameters. The forest restoration using topsoil was effective in triggering a process of soil recovery, promoting, in seven years, chemical and physical characteristics similar to those of the reference ecosystem.

The magnetic susceptibility of soils in Krakow, southern Poland

NASA Astrophysics Data System (ADS)

Wojas, Anna

2017-06-01

Studies into the magnetic susceptibility have been used to assess the soils contamination in the Krakow area. The results of topsoil (over a 2 × 2 km grid), subsoil (37 shallow holes) and soil samples (112) measurements were presented as maps of soil magnetic susceptibility (both volume and mass) illustrating the distribution of parameters in topsoil horizon (0-10 cm) and differential magnetic susceptibility maps between topsoil horizon and subsoil (40-60 cm). All evidence leads to the finding that the highest values of magnetic susceptibility of soil are found exclusively in industrial areas. Taking into consideration the type of land use, the high median value (89.8 × 10-8 m3kg-1) was obtained for samples of cultivated soils and is likely to be connected with occurrence of fertile soil (chernozem). Moreover, enrichment of soils with Pb and Zn accompanies magnetic susceptibility anomalies in the vicinity of the high roads and in the steelworks area, respectively.

Topsoil N-budget model in orchard farming to evaluate groundwater nitrate contamination

NASA Astrophysics Data System (ADS)

Wijayanti, Yureana; Budihardjo, Kadarwati; Sakamoto, Yasushi; Setyandito, Oki

2017-12-01

A small scale field research was conducted in an orchard farming area in Kofu, Japan, where nitrate contamination was found in groundwater. The purpose of assessing the leaching of nitrate in this study is to understand the transformation and transport process of N-source in topsoil that leads to nitrate contamination of groundwater. In order to calculate N-budget in the soil, the model was utilized to predict the nitrogen leaching. In this res earch, the N-budget model was modified to evaluate influence of precipitation and application pattern of fertilizer and manure compost. The result shows that at the time before the addition of manure compost and fertilizer, about 75% of fertilizer leach from topsoil. Every month, the average remaining nitrate in soil from fertilizer and manure compost are 22% and 50%, respectively. The accumulation of this monthly manure compost nitrate, which stored in soil, should be carefully monitored. It could become the potential source of nitrate leaching to groundwater in the future.

Fractal Scaling of Particle Size Distribution and Relationships with Topsoil Properties Affected by Biological Soil Crusts

PubMed Central

Gao, Guang-Lei; Ding, Guo-Dong; Wu, Bin; Zhang, Yu-Qing; Qin, Shu-Gao; Zhao, Yuan-Yuan; Bao, Yan-Feng; Liu, Yun-Dong; Wan, Li; Deng, Ji-Feng

2014-01-01

Background Biological soil crusts are common components of desert ecosystem; they cover ground surface and interact with topsoil that contribute to desertification control and degraded land restoration in arid and semiarid regions. Methodology/Principal Findings To distinguish the changes in topsoil affected by biological soil crusts, we compared topsoil properties across three types of successional biological soil crusts (algae, lichens, and mosses crust), as well as the referenced sandland in the Mu Us Desert, Northern China. Relationships between fractal dimensions of soil particle size distribution and selected soil properties were discussed as well. The results indicated that biological soil crusts had significant positive effects on soil physical structure (P<0.05); and soil organic carbon and nutrients showed an upward trend across the successional stages of biological soil crusts. Fractal dimensions ranged from 2.1477 to 2.3032, and significantly linear correlated with selected soil properties (R2 = 0.494∼0.955, P<0.01). Conclusions/Significance Biological soil crusts cause an important increase in soil fertility, and are beneficial to sand fixation, although the process is rather slow. Fractal dimension proves to be a sensitive and useful index for quantifying changes in soil properties that additionally implies desertification. This study will be essential to provide a firm basis for future policy-making on optimal solutions regarding desertification control and assessment, as well as degraded ecosystem restoration in arid and semiarid regions. PMID:24516668

Contamination characteristics and source apportionment of heavy metals in topsoil from an area in Xi'an city, China.

PubMed

Chen, Xiuduan; Lu, Xinwei

2018-04-30

As soil-extractable elements potentially pose ecological and health risks, identifying their contamination characteristics and sources is crucial. Therefore, to understand topsoil trace elements in the urban ring zone from the Second Ring Road to the Third Ring of Xi'an city in China, we determined the concentrations of Zn, Co, V, As, Cu, Mn, Ba, Ni and Pb, and analyzed the sources of the contamination. The results showed that the individual pollution indices of Pb, Co, Cu, Zn, Ba, Ni, Mn, As, and V were 1.79, 1.48, 1.41, 1.33, 1.20, 1.07, 1.04, 0.99, and 0.99, respectively. Evaluation with the aid of the pollution load index (PLI) indicated slight soil contamination by these elements in the study area. Using the positive matrix factorization (PMF) method, we identified four sources of contamination, namely (1) a natural source, (2) traffic emission source, (3) industrial emission source, and (4) mixed source. PMF is an effective tool for source apportionment of heavy metals in topsoil. The contribution rates of the natural source, traffic source, mixed source, and industrial source to the heavy metal contamination were specified as 25.04%, 24.71%, 24.99%, and 25.26%, respectively. Considering the above, any attempt to reduce the soil environmental cost of urban development, has to take into account the heavy metal contamination of the topsoil from industries, traffic, and other activities. Copyright © 2018 Elsevier Inc. All rights reserved.

[Heavy Metals Pollution in Topsoil from Dagang Industry Area and Its Ecological Risk Assessment].

PubMed

Zhang, Qian; Chen, Zong-juan; Peng, Chang-sheng; Li, Fa-sheng; Gu, Qing-bao

2015-11-01

Based on previous studies and field investigation of Dagang industry area in Tianjin, a total of 128 topsoil samples were collected, and contents of 10 heavy metals (As, Cd, Cr, Co, Cu, Pb, Ni, V, Zn and Hg) were determined. The geoaccumulation index and geostatistics were applied to examine the degree of contamination and spatial distribution of heavy metals in topsoil. The assessment on ecological risk of heavy metals was carried out using Hakanson's method, and the main resources of the heavy metals were analyzed as well. It was found that As, Cd and Co had the highest proportions exceeding Tianjin background value, which were 100%, 97.66% and 96.88%, respectively; the heavy-metal content increased to some extent comparing with that in 2004, and the pollutions of As and Cd were the worst, and other metals were at moderate pollution level or below. The ecological risks of heavy metals were different in topsoil with different land use types, the farmland soil in the southwest as well as soils adjacent to the industrial land were at relatively high potential ecological risk level, and the integrated ecological risk index reached up to 1 437.37. Analysis of correlation and principal component showed that traffic and transportation as well as agricultural activities might be the main resources of heavy metals in the area, besides, the industrial activities in the region might also affect the accumulation of heavy metals.

Does plant diversity affect the water balance of established grassland systems?

NASA Astrophysics Data System (ADS)

Leimer, Sophia; Bischoff, Sebastian; Blaser, Stefan; Boch, Steffen; Busch, Verena; Escher, Peter; Fischer, Markus; Kaupenjohann, Martin; Kerber, Katja; Klaus, Valentin; Michalzik, Beate; Prati, Daniel; Schäfer, Deborah; Schmitt, Barbara; Schöning, Ingo; Schwarz, Martin T.; Siemens, Jan; Thieme, Lisa; Wilcke, Wolfgang

2017-04-01

The water cycle drives nutrient cycles and plant productivity. The impact of land use on the water cycle has been extensively studied and there is experimental evidence that biodiversity modifies the water cycle in grasslands. However, the combined influences of land-use and associated biodiversity on the water cycle in established land-use systems are unclear. Therefore, we investigated how evapotranspiration (ETa), downward water flux (DF), and capillary rise (CR) in topsoil and subsoil are related to land-use and plant diversity in established, commercially managed grassland and compared these results to findings from experiments where plant diversity was manipulated. In three Central European regions ("Biodiversity Exploratories"), we studied 29 grassland plots (50 m x 50 m; 9-11 plots per region) from 2010 to 2015. The land-use types cover pasture, mown pasture, and meadow in at least triplicate per region. On each plot, we measured soil water contents, meteorological data (hourly resolution), cumulative precipitation (biweekly), plant species richness, the number of plants in the functional groups of grasses, herbs, and legumes (annually), and root biomass (once). Potential evapotranspiration (ETp) was calculated from meteorological data per plot. Missing data points of ETp and soil water contents were estimated with Bayesian hierarchical models. ETa, DF, and CR were calculated for two soil layers with a soil water balance model. The model is based on changes in soil water storage between subsequent observation dates and ETp, which was partitioned between soil layers according to root distribution. Water fluxes in annual resolution were statistically analyzed for land-use and biodiversity effects using repeated-measures analysis of variance (ANOVA). Land-use type did not affect water fluxes. Species richness did not influence DF and CR. DF from topsoil was higher on plots with more grass species, which is opposite to the results from a manipulative biodiversity experiment. The number of grasses and herbs influenced CR into topsoil. ETa from topsoil decreased with increasing species richness while ETa from subsoil increased. Opposing effects on ETa in the two soil layers were also observed for the numbers of herb and legume species. In manipulative biodiversity experiments, opposing effects on ETa from different soil layers are explained by higher plant cover and biomass in species-rich mixtures, reducing evaporation by shading of the topsoil, and deeper roots in species-rich mixtures, facilitating water use and increasing transpiration from subsoil. In our study, biomass decreased with increasing species richness because fertilizer application increased biomass production and decreased species richness. Plots with more grasses showed lower ETa from topsoil than plots with less grasses. However, the within-subject effects indicated higher ETa from topsoil in years with more grasses on individual plots than in years with less grasses. The latter finding complies with the results from a manipulative biodiversity experiment, which has homogeneous soil properties and management. The opposite between-subject effect is probably caused by variations in environmental conditions between plots. This indicates that processes controlling the biodiversity-water cycle relationship vary in real-world systems with environmental conditions, which are largely controlled for in manipulative biodiversity experiments.

A survey of topsoil arsenic and mercury concentrations across France.

PubMed

Marchant, B P; Saby, N P A; Arrouays, D

2017-08-01

Even at low concentrations, the presence of arsenic and mercury in soils can lead to ecological and health impacts. The recent European-wide LUCAS Topsoil Survey found that the arsenic concentration of a large proportion of French soils exceeded a threshold which indicated that further investigation was required. A much smaller proportion of soils exceeded the corresponding threshold for mercury but the impacts of mining and industrial activities on mercury concentrations are not well understood. We use samples from the French national soil monitoring network (RMQS: Réseau de Mesures de la Qualité des Sols) to explore the variation of topsoil arsenic and mercury concentrations across mainland France at a finer spatial resolution than was reported by LUCAS Topsoil. We use geostatistical methods to map the expected concentrations of these elements in the topsoil and the probabilities that the legislative thresholds are exceeded. We find that, with the exception of some areas where the geogenic concentrations and soil adsorption capacities are very low, arsenic concentrations are generally larger than the threshold which indicates that further assessment of the area is required. The lower of two other guideline values indicating risks to ecology or health is exceeded in fewer than 5% of RMQS samples. These exceedances occur in localised hot-spots primarily associated with mining and mineralization. The probabilities of mercury concentrations exceeding the further assessment threshold value are everywhere less than 0.01 and none of the RMQS samples exceed either of the ecological and health risk thresholds. However, there are some regions with elevated concentrations which can be related to volcanic material, natural mineralizations and industrial contamination. These regions are more diffuse than the hot-spots of arsenic reflecting the greater volatility of mercury and therefore the greater ease with which it can be transported and redeposited. The maps provide a baseline against which future phases of the RMQS can be compared and highlight regions where the threat of soil contamination and its impacts should be more closely monitored. Copyright © 2017 Elsevier Ltd. All rights reserved.

Application of biosolids in mineral sands mine rehabilitation: use of stockpiled topsoil decreases trace element uptake by plants.

PubMed

Rate, Andrew W; Lee, Karen M; French, Peter A

2004-02-01

Mineral sands mining involves stripping topsoil to access heavy-mineral bearing deposits, which are then rehabilitated to their original state, commonly pasture in south-west Western Australia. Organic amendments such as biosolids (digested sewage sludge) can contribute organic carbon to the rehabilitating system and improve soil chemical fertility and physical conditions. Use of biosolids also introduces the risk of contamination of the soil-plant system with heavy metals, but may be a useful source of trace elements to plants if the concentrations of these elements are low in unamended soil. We expected that biosolids amendment of areas mined for mineral sands would result in increased concentrations of metals in soils and plants, and that metal uptake would be decreased by adding stockpiled topsoil or by liming. A glasshouse experiment growing a mixed annual ryegrass (Lolium rigidum)-subterranean clover (Trifolium subterraneum) sward was conducted using two soil materials (residue sand/clay and conserved topsoil) from a mineral sands mine amended with different rates of biosolids (0, 10, 20, 50 dry t/ha), and including a liming treatment (2 t/ha). Total concentrations of metals (As, Cd, Co, Cr, Cu, Ni, Pb and Zn) in soil increased with increasing rate of biosolids application. Metal uptake was generally lower where topsoil was present and was decreased by liming. With increasing biosolids application, plant metal concentrations increased for Cd, Ni and Zn but decreased or were erratic for other elements. In clover, biosolids application removed the Zn deficiency observed where biosolids were not applied. Plant uptake of all elements increased with increasing biosolids application, suggesting dilution by increased plant biomass was responsible for erratic metal concentration results. Despite the observed increases in uptake of metals by plants, metal concentrations in both species were low and below food standard thresholds. It is unlikely that a single application of biosolids in this system posed a threat from heavy metal contamination of soils or plants, and was beneficial in terms of Zn nutrition of T. subterraneum.

Priming effect in topsoil and subsoil induced by earthworm burrows

NASA Astrophysics Data System (ADS)

Thu, Duyen Hoang Thi

2017-04-01

Earthworms (Lumbricus terrestris L.) not only affect soil physics, but they also boost microbial activities and consequently important hotspots of microbial mediated carbon and C turnover through their burrowing activity. However, it is still unknown to which extend earthworms affect priming effect in top- and subsoil horizons. More labile C inputs in earthworm burrows were hypothesized to trigger higher priming of soil organic matter (SOM) decomposition compared to rhizosphere and bulk soil. Moreover, this effect was expected to be more pronounced in subsoil due to its greater C and nutrient limitation. To test these hypotheses, biopores and bulk soil were sampled from topsoil (0-30 cm) and two subsoil depths (45-75 and 75-105 cm). Additionally, rhizosphere samples were taken from the topsoil. Total organic C (Corg), total N (TN), total P (TP) and enzyme activities involved in C-, N-, and P-cycling (cellobiohydrolase, β-glucosidase, xylanase, chitinase, leucine aminopeptidase and phosphatase) were measured. Priming effects were calculated as the difference in SOM-derived CO2 from soil with or without 14C-labelled glucose addition. Enzyme activities in biopores were positively correlated with Corg, TN and TP, but in bulk soil this correlation was negative. The more frequent fresh and labile C inputs to biopores caused 4 to 20 time higher absolute priming of SOM turnover due to enzyme activities that were one order of magnitude higher than in bulk soil. In subsoil biopores, reduced labile C inputs and lower N availability stimulated priming twofold greater than in topsoil. In contrast, a positive priming effect in bulk soil was only detected at 75-105 cm depth. We conclude that earthworm burrows provide not only the linkage between top- and subsoil for C and nutrients, but strongly increase microbial activities and accelerate SOM turnover in subsoil, contributing to nutrient mobilization for roots and CO2 emission increase as a greenhouse gas. Additionally, the mechanisms of native SOM decomposition are distinct between topsoil and subsoil, which relies on the fresh C input and nutrient availability. Keywords: Priming effect; Earthworms; Organic matter decomposition; Biopores; Subsoil; Microbial hotspots.

Effects of enhancing soil organic carbon sequestration in the topsoil by fertilization on crop productivity and stability: Evidence from long-term experiments with wheat-maize cropping systems in China.

PubMed

Zhang, Xubo; Sun, Nan; Wu, Lianhai; Xu, Minggang; Bingham, Ian J; Li, Zhongfang

2016-08-15

Although organic carbon sequestration in agricultural soils has been recommended as a 'win-win strategy' for mitigating climate change and ensuring food security, great uncertainty still remains in identifying the relationships between soil organic carbon (SOC) sequestration and crop productivity. Using data from 17 long-term experiments in China we determined the effects of fertilization strategies on SOC stocks at 0-20cm depth in the North, North East, North West and South. The impacts of changes in topsoil SOC stocks on the yield and yield stability of winter wheat (Triticum aestivum L.) and maize (Zea mays L.) were determined. Results showed that application of inorganic fertilizers (NPK) plus animal manure over 20-30years significantly increased SOC stocks to 20-cm depth by 32-87% whilst NPK plus wheat/maize straw application increased it by 26-38% compared to controls. The efficiency of SOC sequestration differed between regions with 7.4-13.1% of annual C input into the topsoil being retained as SOC over the study periods. In the northern regions, application of manure had little additional effect on yield compared to NPK over a wide range of topsoil SOC stocks (18->50MgCha(-1)). In the South, average yield from manure applied treatments was 2.5 times greater than that from NPK treatments. Moreover, the yield with NPK plus manure increased until SOC stocks (20-cm depth) increased to ~35MgCha(-1). In the northern regions, yield stability was not increased by application of NPK plus manure compared to NPK, whereas in the South there was a significant improvement. We conclude that manure application and straw incorporation could potentially lead to SOC sequestration in topsoil in China, but beneficial effects of this increase in SOC stocks to 20-cm depth on crop yield and yield stability may only be achieved in the South. Copyright © 2016 Elsevier B.V. All rights reserved.

Meta-modeling of the pesticide fate model MACRO for groundwater exposure assessments using artificial neural networks

NASA Astrophysics Data System (ADS)

Stenemo, Fredrik; Lindahl, Anna M. L.; Gärdenäs, Annemieke; Jarvis, Nicholas

2007-08-01

Several simple index methods that use easily accessible data have been developed and included in decision-support systems to estimate pesticide leaching across larger areas. However, these methods often lack important process descriptions (e.g. macropore flow), which brings into question their reliability. Descriptions of macropore flow have been included in simulation models, but these are too complex and demanding for spatial applications. To resolve this dilemma, a neural network simulation meta-model of the dual-permeability macropore flow model MACRO was created for pesticide groundwater exposure assessment. The model was parameterized using pedotransfer functions that require as input the clay and sand content of the topsoil and subsoil, and the topsoil organic carbon content. The meta-model also requires the topsoil pesticide half-life and the soil organic carbon sorption coefficient as input. A fully connected feed-forward multilayer perceptron classification network with two hidden layers, linked to fully connected feed-forward multilayer perceptron neural networks with one hidden layer, trained on sub-sets of the target variable, was shown to be a suitable meta-model for the intended purpose. A Fourier amplitude sensitivity test showed that the model output (the 80th percentile average yearly pesticide concentration at 1 m depth for a 20 year simulation period) was sensitive to all input parameters. The two input parameters related to pesticide characteristics (i.e. soil organic carbon sorption coefficient and topsoil pesticide half-life) were the most influential, but texture in the topsoil was also quite important since it was assumed to control the mass exchange coefficient that regulates the strength of macropore flow. This is in contrast to models based on the advection-dispersion equation where soil texture is relatively unimportant. The use of the meta-model is exemplified with a case-study where the spatial variability of pesticide leaching is mapped for a small field. It was shown that the area of the field that contributes most to leaching depends on the properties of the compound in question. It is concluded that the simulation meta-model of MACRO should prove useful for mapping relative pesticide leaching risks at large scales.

Leaching of natural colloids from forest topsoils and their relevance for phosphorus mobility.

PubMed

Missong, Anna; Holzmann, Stefan; Bol, Roland; Nischwitz, Volker; Puhlmann, Heike; V Wilpert, Klaus; Siemens, Jan; Klumpp, Erwin

2018-09-01

The leaching of P from the upper 20cm of forest topsoils influences nutrient (re-)cycling and the redistribution of available phosphate and organic P forms. However, the effective leaching of colloids and associated P forms from forest topsoils was so far sparsely investigated. We demonstrated through irrigation experiments with undisturbed mesocosm soil columns, that significant proportions of P leached from acidic forest topsoils were associated with natural colloids. These colloids had a maximum size of 400nm. By means of Field-flow fractionation the leached soil colloids could be separated into three size fractions. The size and composition was comparable to colloids present in acidic forest streams known from literature. The composition of leached colloids of the three size classes was dominated by organic carbon. Furthermore, these colloids contained large concentrations of P which amounted between 12 and 91% of the totally leached P depending on the type of the forest soil. The fraction of other elements leached with colloids ranged between 1% and 25% (Fe: 1-25%; C org : 3-17%; Al: <4%; Si, Ca, Mn: all <2%). The proportion of colloid-associated P decreased with increasing total P leaching. Leaching of total and colloid-associated P from the forest surface soil did not increase with increasing bulk soil P concentrations and were also not related to tree species. The present study highlighted that colloid-facilitated P leaching can be of higher relevance for the P leaching from forest surface soils than dissolved P and should not be neglected in soil water flux studies. Copyright © 2018 Elsevier B.V. All rights reserved.

The effect of geographical indices on left ventricular structure in healthy Han Chinese population

NASA Astrophysics Data System (ADS)

Cen, Minyi; Ge, Miao; Liu, Yonglin; Wang, Congxia; Yang, Shaofang

2017-02-01

The left ventricular posterior wall thickness (LVPWT) and interventricular septum thickness (IVST) are generally regarded as the functional parts of the left ventricular (LV) structure. This paper aims to examine the effects of geographical indices on healthy Han adults' LV structural indices and to offer a scientific basis for developing a unified standard for the reference values of adults' LV structural indices in China. Fifteen terrain, climate, and soil indices were examined as geographical explanatory variables. Statistical analysis was performed using correlation analysis. Moreover, a back propagation neural network (BPNN) and a support vector regression (SVR) were applied to developing models to predict the values of two indices. After the prediction models were built, distribution maps were produced. The results show that LV structural indices are characteristically associated with latitude, longitude, altitude, average temperature, average wind velocity, topsoil sand fraction, topsoil silt fraction, topsoil organic carbon, and topsoil sodicity. The model test analyses show the BPNN model possesses better simulative and predictive ability in comparison with the SVR model. The distribution maps of the LV structural indices show that, in China, the values are higher in the west and lower in the east. These results demonstrate that the reference values of the adults' LV structural indices will be different affected by different geographical environment. The reference values of LV structural indices in one region can be calculated by setting up a BPNN, which showed better applicability in this study. The distribution of the reference values of the LV structural indices can be seen clearly on the geographical distribution map.

The effect of geographical indices on left ventricular structure in healthy Han Chinese population.

PubMed

Cen, Minyi; Ge, Miao; Liu, Yonglin; Wang, Congxia; Yang, Shaofang

2017-02-01

The left ventricular posterior wall thickness (LVPWT) and interventricular septum thickness (IVST) are generally regarded as the functional parts of the left ventricular (LV) structure. This paper aims to examine the effects of geographical indices on healthy Han adults' LV structural indices and to offer a scientific basis for developing a unified standard for the reference values of adults' LV structural indices in China. Fifteen terrain, climate, and soil indices were examined as geographical explanatory variables. Statistical analysis was performed using correlation analysis. Moreover, a back propagation neural network (BPNN) and a support vector regression (SVR) were applied to developing models to predict the values of two indices. After the prediction models were built, distribution maps were produced. The results show that LV structural indices are characteristically associated with latitude, longitude, altitude, average temperature, average wind velocity, topsoil sand fraction, topsoil silt fraction, topsoil organic carbon, and topsoil sodicity. The model test analyses show the BPNN model possesses better simulative and predictive ability in comparison with the SVR model. The distribution maps of the LV structural indices show that, in China, the values are higher in the west and lower in the east. These results demonstrate that the reference values of the adults' LV structural indices will be different affected by different geographical environment. The reference values of LV structural indices in one region can be calculated by setting up a BPNN, which showed better applicability in this study. The distribution of the reference values of the LV structural indices can be seen clearly on the geographical distribution map.

Feed in summer, rest in winter: microbial carbon utilization in forest topsoil.

PubMed

Žifčáková, Lucia; Větrovský, Tomáš; Lombard, Vincent; Henrissat, Bernard; Howe, Adina; Baldrian, Petr

2017-09-18

Evergreen coniferous forests contain high stocks of organic matter. Significant carbon transformations occur in litter and soil of these ecosystems, making them important for the global carbon cycle. Due to seasonal allocation of photosynthates to roots, carbon availability changes seasonally in the topsoil. The aim of this paper was to describe the seasonal differences in C source utilization and the involvement of various members of soil microbiome in this process. Here, we show that microorganisms in topsoil encode a diverse set of carbohydrate-active enzymes, including glycoside hydrolases and auxiliary enzymes. While the transcription of genes encoding enzymes degrading reserve compounds, such as starch or trehalose, was high in soil in winter, summer was characterized by high transcription of ligninolytic and cellulolytic enzymes produced mainly by fungi. Fungi strongly dominated the transcription in litter and an equal contribution of bacteria and fungi was found in soil. The turnover of fungal biomass appeared to be faster in summer than in winter, due to high activity of enzymes targeting its degradation, indicating fast growth in both litter and soil. In each enzyme family, hundreds to thousands of genes were typically transcribed simultaneously. Seasonal differences in the transcription of glycoside hydrolases and auxiliary enzyme genes are more pronounced in soil than in litter. Our results suggest that mainly fungi are involved in decomposition of recalcitrant biopolymers in summer, while bacteria replace them in this role in winter. Transcripts of genes encoding enzymes targeting plant biomass biopolymers, reserve compounds and fungal cell walls were especially abundant in the coniferous forest topsoil.

Feedbacks between soil penetration resistance, root architecture and water uptake limit water accessibility and crop growth - A vicious circle.

PubMed

Colombi, Tino; Torres, Lorena Chagas; Walter, Achim; Keller, Thomas

2018-06-01

Water is the most limiting resource for global crop production. The projected increase of dry spells due to climate change will further increase the problem of water limited crop yields. Besides low water abundance and availability, water limitations also occur due to restricted water accessibility. Soil penetration resistance, which is largely influenced by soil moisture, is the major soil property regulating root elongation and water accessibility. Until now the interactions between soil penetration resistance, root system properties, water uptake and crop productivity are rarely investigated. In the current study we quantified how interactive effects between soil penetration resistance, root architecture and water uptake affect water accessibility and crop productivity in the field. Maize was grown on compacted and uncompacted soil that was either tilled or remained untilled after compaction, which resulted in four treatments with different topsoil penetration resistance. Higher topsoil penetration resistance caused root systems to be shallower. This resulted in increased water uptake from the topsoil and hence topsoil drying, which further increased the penetration resistance in the uppermost soil layer. As a consequence of this feedback, root growth into deeper soil layers, where water would have been available, was reduced and plant growth decreased. Our results demonstrate that soil penetration resistance, root architecture and water uptake are closely interrelated and thereby determine the potential of plants to access soil water pools. Hence, these interactions and their feedbacks on water accessibility and crop productivity have to be accounted for when developing strategies to alleviate water limitations in cropping systems. Copyright © 2018 Elsevier B.V. All rights reserved.

Effect of Remediation Parameters on in-Air Ambient Dose Equivalent Rates When Remediating Open Sites with Radiocesium-contaminated Soil.

PubMed

Malins, Alex; Kurikami, Hiroshi; Kitamura, Akihiro; Machida, Masahiko

2016-10-01

Calculations are reported for ambient dose equivalent rates [H˙*(10)] at 1 m height above the ground surface before and after remediating radiocesium-contaminated soil at wide and open sites. The results establish how the change in H˙*(10) upon remediation depends on the initial depth distribution of radiocesium within the ground, on the size of the remediated area, and on the mass per unit area of remediated soil. The remediation strategies considered were topsoil removal (with and without recovering with a clean soil layer), interchanging a topsoil layer with a subsoil layer, and in situ mixing of the topsoil. The results show the ratio of the radiocesium components of H˙*(10) post-remediation relative to their initial values (residual dose factors). It is possible to use the residual dose factors to gauge absolute changes in H˙*(10) upon remediation. The dependency of the residual dose factors on the number of years elapsed after fallout deposition is analyzed when remediation parameters remain fixed and radiocesium undergoes typical downward migration within the soil column.

Ecological studies on the revegetation process of surface coal mined areas in North Dakota. 9. Viability and diversity of the seed bank. Final report Aug 75-Jun 82

DOE Office of Scientific and Technical Information (OSTI.GOV)

Iverson, L.R.; Brophy, L.

1982-06-01

Analysis of seed numbers present in topsoils indicated that seeds of the most prevalent colonizers (e.g. Kochia scoparia, Setaria virdis, and Salsola collins) were not present in the topsoil upon respreading but rather appeared by immigration from the surrounding areas. Seed bank analysis was also undertaken on mined sites ranging in age of 2 to 6 years. As with the previous part of this study there was a poor correlation between the aboveground flora and the belowground seed composition.

Carbon turnover in topsoil and subsoil: The microbial response to root litter additions and different environmental conditions in a reciprocal soil translocation experiment

NASA Astrophysics Data System (ADS)

Preusser, Sebastian; Poll, Christian; Marhan, Sven; Kandeler, Ellen

2017-04-01

At the global scale, soil organic carbon (SOC) represents the largest active terrestrial organic carbon (OC) pool. Carbon dynamics in subsoil, however, vary from those in topsoil with much lower C concentrations in subsoil than in topsoil horizons, although more than 50 % of SOC is stored in subsoils below 30 cm soil depth. In addition, microorganisms in subsoil are less abundant, more heterogeneously distributed and the microbial communities have a lower diversity than those in topsoil. Especially in deeper soil, the impact of changes in habitat conditions on microorganisms involved in carbon cycling are largely unexplored and consequently the understanding of microbial functioning is limited. A reciprocal translocation experiment allowed us to investigate the complex interaction effects of altered environmental and substrate conditions on microbial decomposer communities in both topsoil and subsoil habitats under in situ conditions. We conducted this experiment with topsoil (5 cm soil depth) and subsoil (110 cm) samples of an acid and sandy Dystric Cambisol from a European beech (Fagus sylvatica L.) forest in Lower Saxony, Germany. In total 144 samples were buried into three depths (5 cm, 45 cm and 110 cm) and 13C-labelled root litter was added to expose the samples to different environmental conditions and to increase the substrate availability, respectively. Samples were taken in three month intervals up to a maximum exposure time of one year to follow the temporal development over the experimental period. Analyses included 13Cmic and 13C PLFA measurements to investigate the response of microbial abundance, community structure and 13C-root decomposition activity under the different treatments. Environmental conditions in the respective soil depths such as soil temperature and water content were recorded throughout the experimental period. All microbial groups (gram+ and gram- bacteria, fungi) showed highest relative 13C incorporation in 110 cm depth and samples with root addition had generally higher microbial abundances than those with no root addition. Here, especially fungi benefited from the additional carbon source with highly increased abundances in all incorporation depths. Also the altered environmental conditions in the different incorporation depths significantly influenced the different microbial groups. The steepest decrease with depth was detected in fungal abundance, while bacteria were less affected and increased in relative abundance in soil samples incorporated into subsoil layers. The highest seasonal variability in microbial abundance, however, was determined in 5 cm incorporation depth demonstrating the higher amplitude in micro-climatic and micro-environmental conditions in this near-surface soil habitat. In summary, this experiment demonstrated that carbon quality and quantity are the main factors restricting fungal abundance in deeper soil layers, while bacterial decomposer communities are adapted to a wider range of habitat conditions.

Geochemical and Pb isotopic characterization of soil, groundwater, human hair, and corn samples from the Domizio Flegreo and Agro Aversano area (Campania region, Italy)

USGS Publications Warehouse

Rezza, Carmela; Albanese, Stefano; Ayuso, Robert A.; Lima, Annamaria; Sorvari, Jaana; De Vivo, Benedetto

2018-01-01

A geochemical survey was carried out to investigate metal contamination in the Domizio Littoral and Agro Aversano area (Southern Italy) by means of soil, groundwater, human hair and corn samples. Pb isotope ratios were also determined to identify the sources of metals. Specifically, the investigation focused on topsoils (n = 1064), groundwater (n = 26), 25 human hair (n = 24) and corn samples (n = 13). Topsoils have been sampled and analysed in a previous study for 53 elements (including potentially harmful ones), and determined by ICP-MS after dissolving with aqua regia. Groundwater was analysed for 72 elements by ICP-MS and by ICP-ES. Samples of human hair were prepared and analysed for 16 elements by ICP-MS. Dried corn collected at several farms were also analysed for 53 elements by ICP-MS. The isotopic ratios of 206Pb/207Pb and 208Pb/207Pb in selected topsoil (n = 24), groundwater (n = 9), human hair (n = 9) and corn (n = 4) samples were analysed from both eluates and residues to investigate possible anthropogenic contamination and geogenic contributions. All data were processed and mapped by ArcGis software to produce interpolated maps and contamination factor maps of potentially harmful elements, in accordance with Italian Environmental Law (Legislative Decree 152/06). Results show that soil sampling sites are characterized by As, Cd, Co, Cr, Cu, Hg, Pb, Se, and Zn contents exceeding the action limits established for residential land use (RAL) and, in some cases, also the action limits for industrial land use (IAL) as established by Legislative Decree 152/06. A map of contamination factors and a map showing the degrees of contamination indicate that the areas in the municipalities of Acerra, Casoria and Giugliano have been affected by considerable anthropogenic-related pollution. To interpret the isotopic data and roughly estimate proportion of Pb from an anthropogenic source we broadly defined possible natural and anthropogenic Pb end-member fields based on literature data. For example, we summarized data for Vesuvius and Campi Flegrei volcanic rocks, gasoline, and aerosol deposits.Lead isotope data show mixing between geogenic and anthropogenic sources. Topsoil, groundwater, human hair and corn samples show a greater contribution from geogenic sources like the Yellow Tuff (from Campi Flegrei) and volcanic rocks from Mt. Vesuvius. Aerosols, fly ash and gasoline (anthropogenic sources) have also been contributors. In detail, 46% of the topsoil residues, 96% of topsoil leachates, 88% of groundwater, 90% of human hair, and 25% of corn samples indicate that > 50% percent of the lead in this area can be ascribed to anthropogenic activity.

Surface and Airborne Arsenic Concentrations in a Recreational Site near Las Vegas, Nevada, USA

PubMed Central

Goossens, Dirk

2015-01-01

Elevated concentrations of arsenic, up to 7058 μg g-1 in topsoil and bedrock, and more than 0.03 μg m-3 in air on a 2-week basis, were measured in the Nellis Dunes Recreation Area (NDRA), a very popular off-road area near Las Vegas, Nevada, USA. The elevated arsenic concentrations in the topsoil and bedrock are correlated to outcrops of yellow sandstone belonging to the Muddy Creek Formation (≈ 10 to 4 Ma) and to faults crossing the area. Mineralized fluids moved to the surface through the faults and deposited the arsenic. A technique was developed to calculate airborne arsenic concentrations from the arsenic content in the topsoil. The technique was tested by comparing calculated with measured concentrations at 34 locations in the NDRA, for 3 periods of 2 weeks each. We then applied it to calculate airborne arsenic concentrations for more than 500 locations all over the NDRA. The highest airborne arsenic concentrations occur over sand dunes and other zones with a surficial layer of aeolian sand. Ironically these areas show the lowest levels of arsenic in the topsoil. However, they are highly susceptible to wind erosion and emit very large amounts of sand and dust during episodes of strong winds, thereby also emitting much arsenic. Elsewhere in the NDRA, in areas not or only very slightly affected by wind erosion, airborne arsenic levels equal the background level for airborne arsenic in the USA, approximately 0.0004 μg m-3. The results of this study are important because the NDRA is visited by more than 300,000 people annually. PMID:25897667

Fate of the fecal indicator Escherichia coli in irrigation with partially treated wastewater.

PubMed

Vergine, P; Saliba, R; Salerno, C; Laera, G; Berardi, G; Pollice, A

2015-11-15

Treated wastewater reuse is increasing in semi-arid regions as a response to the effects of climate change and increased competition for natural water resources. Investigating the fate of bacterial indicators is relevant to assess their persistence in the environment and possible transfer to groundwater or to the food chain. A long-term field-scale experimental campaign and a soil column test were carried out to evaluate the fate of the fecal indicator Escherichia coli (E. coli) in a cultivated soil when contaminated water resources are used for irrigation. For field experiments, fecal contamination was simulated by dosing the indicator to the effluent of a membrane bioreactor, thus simulating a filtration system's failure, and irrigating a test field where grass was grown. The presence of E. coli on grass and topsoil samples was monitored under different scenarios. For evaluating the fate of the same indicator in the subsoil, a set of soil columns was installed next to the field, operated, and monitored for E. coli concentration over time and along depth. Real municipal wastewater was used in this case as source of fecal contamination. Results showed that short- and medium-term effects on topsoil were strongly dependent on the concentration of E. coli in the irrigation water. Limited persistence and no relevant accumulation of the indicator on the grass and in the topsoil were observed. Watering events performed after fecal contamination did not influence significantly the decay in the topsoil, which followed a log-linear model. The trend of the E. coli concentrations in the leaching of the soil columns followed a log-linear model as well, suggesting bacterial decay as the dominant mechanism affecting the underground indicator's concentration. Copyright © 2015 Elsevier Ltd. All rights reserved.

Results of the second national forest soil inventory in Germany - Interpretation of level and stock profiles for PCDD/F and PCB in terms of vegetation and humus type.

PubMed

Pandelova, Marchela; Henkelmann, Bernhard; Bussian, Bernd M; Schramm, Karl-Werner

2018-01-01

Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) were detected in 86 humic topsoil layers and in a subset of 11 randomly selected top mineral forest soils at the depths of 0-5cm and 5-10cm collected from different federal states of Germany. The distribution of these persistent organic pollutants (POPs) in humic topsoils with respect to vegetation cover (coniferous vs. deciduous vs. mixed), total organic carbon (TOC), altitude and latitude data was investigated. There is cross correlation between the contents and TOC while the correlation with latitude indicates higher abundances of POPs in central Germany where there is high population density accompanied with industrial activities. The calculated stocks suggest that humus type (mor, mull, or moder) in conjunction with forest type can explain the relative POPs abundances in different soil layers. Generally, humic topsoils show highest contents of POPs compare to the two mineral soils with a ratio of 100:10:1. However, the stock humic layers of coniferous stands contribute about 50% to the total stock, whereas at deciduous stands the stock is mainly located in the upper mineral soil layer (0-5cm). The soil-water distribution coefficients (Kd) were calculated to estimate the potential translocation in the different soil types. The Kd values vary among the PCBs and PCDD/Fs congeners and are most variable for humic topsoils. There is pronounced chemical abundance in the top mineral soils with increasing Kd and this points to non-water bound transport processes for superlipophilic compounds. Copyright © 2017 Elsevier B.V. All rights reserved.

Citrus stand ages regulate the fraction alteration of soil organic carbon under a citrus/Stropharua rugodo-annulata intercropping system in the Three Gorges Reservoir area, China.

PubMed

Zhang, Yang; Ni, Jiupai; Yang, John; Zhang, Tong; Xie, Deti

2017-08-01

Soil carbon fractionation is a valuable indicator in assessing stabilization of soil organic matter and soil quality. However, limited studies have addressed how different vegetation stand ages under intercropping agroforestry systems, could affect organic carbon (OC) accumulation in bulk soil and its physical fractions. A field study thus investigated the impact of citrus plantation age (15-, 25-, and 45-year citrus) on the bulk soil organic carbon (SOC) and SOC fractions and yields of Stropharia rugoso-annulata (SRA) in the Three Gorges Reservoir area, Chongqing, China. Results indicated that the intercropping practice of SRA with citrus significantly increased the SOC by 57.4-61.6% in topsoil (0-10 cm) and by 24.8-39.9% in subsoil (10-30 cm). With a significantly higher enhancement under the 25-year citrus stand than the other two stands, all these citrus stands of three ages also resulted in a significant increase of free particulate OC (fPOC, 60.1-62.4% in topsoil and 34.8-46.7% in subsoil), intra-micro aggregate particulate OC (iPOC, 167.6-206.0% in topsoil and 2.77-61.09% in subsoil), and mineral-associated OC (MOC, 43.6-46.5% in topsoil and 26.0-51.5% in subsoil). However, there were no significant differences in yields of SRA under three citrus stands. Our results demonstrated that citrus stand ages did play an important role in soil carbon sequestration and fractionation under a citrus/SRA intercropping system, which could therefore provide a sustainable agroforestry system to enhance concurrently the SOC accumulation while mitigating farmland CO 2 emission.

Microbial Community and Biochemical Dynamics of Biological Soil Crusts across a Gradient of Surface Coverage in the Central Mojave Desert.

PubMed

Mogul, Rakesh; Vaishampayan, Parag; Bashir, Mina; McKay, Chris P; Schubert, Keith; Bornaccorsi, Rosalba; Gomez, Ernesto; Tharayil, Sneha; Payton, Geoffrey; Capra, Juliana; Andaya, Jessica; Bacon, Leonard; Bargoma, Emily; Black, David; Boos, Katie; Brant, Michaela; Chabot, Michael; Chau, Danny; Cisneros, Jessica; Chu, Geoff; Curnutt, Jane; DiMizio, Jessica; Engelbrecht, Christian; Gott, Caroline; Harnoto, Raechel; Hovanesian, Ruben; Johnson, Shane; Lavergne, Britne; Martinez, Gabriel; Mans, Paul; Morales, Ernesto; Oei, Alex; Peplow, Gary; Piaget, Ryan; Ponce, Nicole; Renteria, Eduardo; Rodriguez, Veronica; Rodriguez, Joseph; Santander, Monica; Sarmiento, Khamille; Scheppelmann, Allison; Schroter, Gavin; Sexton, Devan; Stephenson, Jenin; Symer, Kristin; Russo-Tait, Tatiane; Weigel, Bill; Wilhelm, Mary B

2017-01-01

In this study, we expand upon the biogeography of biological soil crusts (BSCs) and provide molecular insights into the microbial community and biochemical dynamics along the vertical BSC column structure, and across a transect of increasing BSC surface coverage in the central Mojave Desert, CA, United States. Next generation sequencing reveals a bacterial community profile that is distinct among BSCs in the southwestern United States. Distribution of major phyla in the BSC topsoils included Cyanobacteria (33 ± 8%), Proteobacteria (26 ± 6%), and Chloroflexi (12 ± 4%), with Phormidium being the numerically dominant genus. Furthermore, BSC subsurfaces contained Proteobacteria (23 ± 5%), Actinobacteria (20 ± 5%), and Chloroflexi (18 ± 3%), with an unidentified genus from Chloroflexi (AKIW781, order) being numerically dominant. Across the transect, changes in distribution at the phylum ( p < 0.0439) and genus ( p < 0.006) levels, including multiple biochemical and geochemical trends ( p < 0.05), positively correlated with increasing BSC surface coverage. This included increases in (a) Chloroflexi abundance, (b) abundance and diversity of Cyanobacteria, (b) OTU-level diversity in the topsoil, (c) OTU-level differentiation between the topsoil and subsurface, (d) intracellular ATP abundances and catalase activities, and (e) enrichments in clay, silt, and varying elements, including S, Mn, Co, As, and Pb, in the BSC topsoils. In sum, these studies suggest that BSCs from regions of differing surface coverage represent early successional stages, which exhibit increasing bacterial diversity, metabolic activities, and capacity to restructure the soil. Further, these trends suggest that BSC successional maturation and colonization across the transect are inhibited by metals/metalloids such as B, Ca, Ti, Mn, Co, Ni, Mo, and Pb.

Topsoil structure stability in a restored floodplain: Impacts of fluctuating water levels, soil parameters and ecosystem engineers.

PubMed

Schomburg, A; Schilling, O S; Guenat, C; Schirmer, M; Le Bayon, R C; Brunner, P

2018-10-15

Ecosystem services provided by floodplains are strongly controlled by the structural stability of soils. The development of a stable structure in floodplain soils is affected by a complex and poorly understood interplay of hydrological, physico-chemical and biological processes. This paper aims at analysing relations between fluctuating groundwater levels, soil physico-chemical and biological parameters on soil structure stability in a restored floodplain. Water level fluctuations in the soil are modelled using a numerical surface-water-groundwater flow model and correlated to soil physico-chemical parameters and abundances of plants and earthworms. Causal relations and multiple interactions between the investigated parameters are tested through structural equation modelling (SEM). Fluctuating water levels in the soil did not directly affect the topsoil structure stability, but indirectly through affecting plant roots and soil parameters that in turn determine topsoil structure stability. These relations remain significant for mean annual days of complete and partial (>25%) water saturation. Ecosystem functioning of a restored floodplain might already be affected by the fluctuation of groundwater levels alone, and not only through complete flooding by surface water during a flood period. Surprisingly, abundances of earthworms did not show any relation to other variables in the SEM. These findings emphasise that earthworms have efficiently adapted to periodic stress and harsh environmental conditions. Variability of the topsoil structure stability is thus stronger driven by the influence of fluctuating water levels on plants than by the abundance of earthworms. This knowledge about the functional network of soil engineering organisms, soil parameters and fluctuating water levels and how they affect soil structural stability is of fundamental importance to define management strategies of near-natural or restored floodplains in the future. Copyright © 2018 Elsevier B.V. All rights reserved.

Microbial Community and Biochemical Dynamics of Biological Soil Crusts across a Gradient of Surface Coverage in the Central Mojave Desert

PubMed Central

Mogul, Rakesh; Vaishampayan, Parag; Bashir, Mina; McKay, Chris P.; Schubert, Keith; Bornaccorsi, Rosalba; Gomez, Ernesto; Tharayil, Sneha; Payton, Geoffrey; Capra, Juliana; Andaya, Jessica; Bacon, Leonard; Bargoma, Emily; Black, David; Boos, Katie; Brant, Michaela; Chabot, Michael; Chau, Danny; Cisneros, Jessica; Chu, Geoff; Curnutt, Jane; DiMizio, Jessica; Engelbrecht, Christian; Gott, Caroline; Harnoto, Raechel; Hovanesian, Ruben; Johnson, Shane; Lavergne, Britne; Martinez, Gabriel; Mans, Paul; Morales, Ernesto; Oei, Alex; Peplow, Gary; Piaget, Ryan; Ponce, Nicole; Renteria, Eduardo; Rodriguez, Veronica; Rodriguez, Joseph; Santander, Monica; Sarmiento, Khamille; Scheppelmann, Allison; Schroter, Gavin; Sexton, Devan; Stephenson, Jenin; Symer, Kristin; Russo-Tait, Tatiane; Weigel, Bill; Wilhelm, Mary B.

2017-01-01

In this study, we expand upon the biogeography of biological soil crusts (BSCs) and provide molecular insights into the microbial community and biochemical dynamics along the vertical BSC column structure, and across a transect of increasing BSC surface coverage in the central Mojave Desert, CA, United States. Next generation sequencing reveals a bacterial community profile that is distinct among BSCs in the southwestern United States. Distribution of major phyla in the BSC topsoils included Cyanobacteria (33 ± 8%), Proteobacteria (26 ± 6%), and Chloroflexi (12 ± 4%), with Phormidium being the numerically dominant genus. Furthermore, BSC subsurfaces contained Proteobacteria (23 ± 5%), Actinobacteria (20 ± 5%), and Chloroflexi (18 ± 3%), with an unidentified genus from Chloroflexi (AKIW781, order) being numerically dominant. Across the transect, changes in distribution at the phylum (p < 0.0439) and genus (p < 0.006) levels, including multiple biochemical and geochemical trends (p < 0.05), positively correlated with increasing BSC surface coverage. This included increases in (a) Chloroflexi abundance, (b) abundance and diversity of Cyanobacteria, (b) OTU-level diversity in the topsoil, (c) OTU-level differentiation between the topsoil and subsurface, (d) intracellular ATP abundances and catalase activities, and (e) enrichments in clay, silt, and varying elements, including S, Mn, Co, As, and Pb, in the BSC topsoils. In sum, these studies suggest that BSCs from regions of differing surface coverage represent early successional stages, which exhibit increasing bacterial diversity, metabolic activities, and capacity to restructure the soil. Further, these trends suggest that BSC successional maturation and colonization across the transect are inhibited by metals/metalloids such as B, Ca, Ti, Mn, Co, Ni, Mo, and Pb. PMID:29109701

Contamination of woody habitat soils around a former lead smelter in the North of France.

PubMed

Douay, F; Pruvot, C; Waterlot, C; Fritsch, C; Fourrier, H; Loriette, A; Bidar, G; Grand, C; de Vaufleury, A; Scheifler, R

2009-10-15

The contamination of the topsoil of 262 woody habitats around a former lead smelter in the North of France was assessed. In this urbanized and industrialized area, these kinds of habitats comprise of hedges, groves, small woods, anthropogenic creations and one large forest. Except for the latter, which is 3 km away, these woody habitat soils often present a high anthropization degree (a significant amount of pebbles and stones related to human activities) with a high metal contamination. In the studied woody habitat topsoils, Cd, Pb and Zn concentrations largely exceeded those of agricultural topsoils located in the same environmental context. Therefore, atmospheric emissions from the smelter are not the only cause of the high contamination of the woody habitat soils. This last one is related to the nature and the contamination level of deposit in relation with human activities (rubbles, slag, soils, etc). With regard to the results obtained with chemical extractions, the mobility of Cd, Pb and Zn in these soils is also greater than in agricultural soils. In the forest, pollutant solubility is increased by soil acidic pH. The variability of the physico-chemical parameters and the high metal contamination of the topsoils are the main characteristics of the woody habitats located around the former smelter. Although never taken into account during risk assessment, the disturbance of these environmental components could have important biogeochemical impacts (nutrients and metal cycles). Moreover, any modification of the soils' use could potentially cause mobilization and transfer of the pollutants to the biosphere. Six years after the closure of the smelter, and as social and economic pressures considerably increase in this area, the study of these peculiar ecosystems is necessary to understand and predict the bioavailability, transfer, bioaccumulation and effects of pollutants in food chains.

Trace metals from historical mining sites and past metallurgical activity remain bioavailable to wildlife today.

PubMed

Camizuli, Estelle; Scheifler, Renaud; Garnier, Stéphane; Monna, Fabrice; Losno, Rémi; Gourault, Claude; Hamm, Gilles; Lachiche, Caroline; Delivet, Guillaume; Chateau, Carmela; Alibert, Paul

2018-02-21

Throughout history, ancient human societies exploited mineral resources all over the world, even in areas that are now protected and considered to be relatively pristine. Here, we show that past mining still has an impact on wildlife in some French protected areas. We measured cadmium, copper, lead, and zinc concentrations in topsoils and wood mouse kidneys from sites located in the Cévennes and the Morvan. The maximum levels of metals in these topsoils are one or two orders of magnitude greater than their commonly reported mean values in European topsoils. The transfer to biota was effective, as the lead concentration (and to a lesser extent, cadmium) in wood mouse kidneys increased with soil concentration, unlike copper and zinc, providing direct evidence that lead emitted in the environment several centuries ago is still bioavailable to free-ranging mammals. The negative correlation between kidney lead concentration and animal body condition suggests that historical mining activity may continue to play a role in the complex relationships between trace metal pollution and body indices. Ancient mining sites could therefore be used to assess the long-term fate of trace metals in soils and the subsequent risks to human health and the environment.

Pesticide degradation in a 'biobed' composting substrate.

PubMed

Fogg, Paul; Boxall, Alistair B A; Walker, Allan; Jukes, Andrew A

2003-05-01

Pesticides play an important role in the success of modern farming and food production. However, the release of pesticides to the environment arising from non-approved use, poor practice, illegal operations or misuse is increasingly recognised as contributing to water contamination. Biobeds appear to offer a cost-effective method for treating pesticide-contaminated waste. This study was performed to determine whether biobeds can degrade relatively complex pesticide mixtures when applied repeatedly. A pesticide mixture containing isoproturon, pendimethalin, chlorpyrifos, chlorothalonil, epoxiconazole and dimethoate was incubated in biomix and topsoil at concentrations to simulate pesticide disposal. Although the data suggest that interactions between pesticides are possible, the effects were of less significance in biomix than in topsoil. The same mixture was applied on three occasions at 30-day intervals. Degradation was significantly quicker in biomix than in topsoil. The rate of degradation, however, decreased with each additional treatment, possibly due to the toxicity of the pesticide mixture to the microbial community. Incubations with chlorothalonil and pendimethalin carried out in sterile and non-sterile biomix indicated that degradation, rather than irreversible adsorption to the matrix, was the main mechanism responsible for the reduction in recovered residues. Results from these experiments suggest that biobeds offer a viable means of treating pesticide waste.

Decreased Soil Cation Exchange Capacity Across Northern China's Grasslands Over the Last Three Decades

NASA Astrophysics Data System (ADS)

Fang, Kai; Kou, Dan; Wang, Guanqin; Chen, Leiyi; Ding, Jinzhi; Li, Fei; Yang, Guibiao; Qin, Shuqi; Liu, Li; Zhang, Qiwen; Yang, Yuanhe

2017-11-01

Cation exchange capacity (CEC) helps soils hold nutrients and buffer pH, making it vital for maintaining basic function of terrestrial ecosystems. However, little is known about the temporal dynamics of CEC over broad geographical scales. In this study, we used random forest method to compare historical CEC data from the 1980s with new data from the 2010s across northern China's grasslands. We found that topsoil CEC in the 2010s was significantly lower than in the 1980s, with an overall decline of about 14%. Topsoil CEC decreased significantly in alpine meadow, alpine steppe, meadow steppe, and typical steppe by 11%, 20%, 27%, and 9%, respectively. Desert steppe was the only ecosystem type that experienced no significant change. CEC was positively related to soil carbon content, silt content, and mean annual precipitation, suggesting that the decline was potentially associated with soil organic carbon loss, soil degradation, soil acidification, and extreme precipitation across northern China's grasslands since the 1980s. Overall, our results demonstrate topsoil CEC loss due to environmental changes, which may alter the vegetation community composition and its productivity and thus trigger grassland dynamics under a changing environment.

Spatial analysis of subsoil compaction on cultivated land by means of penetrometry, electrical resistence tomography and X-ray computed tomography

NASA Astrophysics Data System (ADS)

Zumr, David; Vláčilová, Markéta; Dostál, Tomáš; Jeřábek, Jakub; Sobotková, Martina; Sněhota, Michal

2015-04-01

Soil compaction is a well recognized phenomena in the agricultural land. Various effects can alter the degree of the compaction in the field. The topsoil is regularly loosened due to agrotechnical operations, but the subsoil remains usually compacted. Various studies show increasing bulk density and decreasing saturated hydraulic conductivity in the plough pan, even though some authors argue that it does not have to be always the case due to presence of bio-macropores. Hence the structural properties of the subsoil and the spatial distribution of the compacted layer depth within the cultivated fields are important factors influencing soil water regime, nutrients regime and runoff generation. The aim of the contribution is to present the results of the monitoring of the plough pan depth spatial distribution at the experimental catchment Nucice (Central Bohemia, Czech Republic). The soils are classified as Luvisols and Cambisols with a loamy Ap horizon (0.1 - 0.2 m deep) underlined by a silty and silty-clay B horizon. The content of clay particles in the topsoil is around 8%. The soil has low inner aggregate (soil matrix) hydraulic conductivity, with measured values of approximately 0.1 - 2 cm d-1. The bulk topsoil saturated hydraulic conductivity (Ks) is significantly higher and varies depending on the season. To observe the divide between topsoil and subsoil layers in detail and to be able to compare the soil structure and pore networks of both layers we inspected undisturbed soil samples with X-ray computed tomography. The divide between the conservatively tilled topsoil and the subsoil is clearly observable also on terrain. To identify its exact position we implemented a combination of penetrometry, soil sampling and electrical resistance tomography (ERT). The penetration tests accompanied by soil probing were done in an irregular network across the whole catchment based on the slopes and distance to the stream. Several 2D ERT measurements were done locally on a plot of approximately 10 x 50 m. Dipole-dipole scheme with electrode span of 10 cm was used. The results obtained by different techniques are in a good agreement with observed plough pan position. The contribution was prepared within the project of Czech Science Foundation No. 13-20388P. We thank Johannes Koestel from SLU Uppsala for his great help during CT imaging of the soil samples.

Distribution of glyphosate and aminomethylphosphonic acid (AMPA) in agricultural topsoils of the European Union.

PubMed

Silva, Vera; Montanarella, Luca; Jones, Arwyn; Fernández-Ugalde, Oihane; Mol, Hans G J; Ritsema, Coen J; Geissen, Violette

2018-04-15

Approval for glyphosate-based herbicides in the European Union (EU) is under intense debate due to concern about their effects on the environment and human health. The occurrence of glyphosate residues in European water bodies is rather well documented whereas only few, fragmented and outdated information is available for European soils. We provide the first large-scale assessment of distribution (occurrence and concentrations) of glyphosate and its main metabolite aminomethylphosphonic acid (AMPA) in EU agricultural topsoils, and estimate their potential spreading by wind and water erosion. Glyphosate and/or AMPA were present in 45% of the topsoils collected, originating from eleven countries and six crop systems, with a maximum concentration of 2mgkg -1 . Several glyphosate and AMPA hotspots were identified across the EU. Soil loss rates (obtained from recently derived European maps) were used to estimate the potential export of glyphosate and AMPA by wind and water erosion. The estimated exports, result of a conceptually simple model, clearly indicate that particulate transport can contribute to human and environmental exposure to herbicide residues. Residue threshold values in soils are urgently needed to define potential risks for soil health and off site effects related to export by wind and water erosion. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Do reclamation speed up recovery of soil and soil biota on post mining sites along climatic gradient across continental USA?

NASA Astrophysics Data System (ADS)

Frouz, Jan

2015-04-01

Soil biota community (macrofauna, nematodes and microbial community studied by PLFA) was studied together with soil development in post-mining chronosequences along climatic gradient in the USA, covering hardwood forest (TN, IN), tallgrass prairie (IL), or shortgrass prairie (WY). Post mining sites reclaimed according recent regulation which includes topsoil application and vegetation establishment were compared to local climax. Both young and old restoration sites were much closer to the climax condition in shortgrass prairie than in the other sites. The shortgrass prairie soil community contained abundant root-feeding organisms, which may establish quicker than the saprophagous fauna that was abundant at the other sites. Absence of saprophagous groups, and especially earthworms, resulted in the absence of bioturbation in shortgrass prairie sites while in chronosequences other than the one in shortgrass prairie, bioturbation played an important role in topsoil formation resulting in more complex soil profile development compare to shortgrass prairie. This may contribute to faster recovery communities in shortgrass prairie in comparison with tallgrass prairie and forest as At the same time sites that were reclaimed according recent regulation (topsoil application and vegetation establishment) were compare to unreclaimed sites both about 30 years old in TN IL and WY. It TN soil and soil biota seems to approach fasted to climax in unreclaimed than reclaimed sites. In IL this differences between reclaimed and unreclaimed sites was not so clear. While in WY reclaimed sites seems to approach to climax community fasted than unreclaimed one. This suggests that effect of reclamation vary along climatic gradient. In drier sites, formation of soil matrix from parent material is probably much slower and topsoil application speed up soil community recovery substantially while this effect is less pronounces in more wet sites, where soil compaction due to restoration may in some cases even slow recovery.

Climate and soil factors influencing seedling recruitment of plant species used for dryland restoration

NASA Astrophysics Data System (ADS)

Muñoz-Rojas, Miriam; Erickson, Todd E.; Martini, Dylan C.; Dixon, Kingsley W.; Merritt, David J.

2016-06-01

Land degradation affects 10-20 % of drylands globally. Intensive land use and management, large-scale disturbances such as extractive operations, and global climate change, have contributed to degradation of these systems worldwide. Restoring these damaged environments is critical to improving ecosystem services and functions, conserve biodiversity, and contribute to climate resilience, food security, and landscape sustainability. Here, we present a case study on plant species of the mining intensive semi-arid Pilbara region in Western Australia that examines the effects of climate and soil factors on the restoration of drylands. We analysed the effects of a range of rainfall and temperature scenarios and the use of alternative soil materials on seedling recruitment of key native plant species from this area. Experimental studies were conducted in controlled environment facilities where conditions simulated those found in the Pilbara. Soil from topsoil (T) stockpiles and waste materials (W) from an active mine site were mixed at different proportions (100 % T, 100 % W, and two mixes of topsoil and waste at 50 : 50 and 25 : 75 ratios) and used as growth media. Our results showed that seedling recruitment was highly dependent on soil moisture and emergence was generally higher in the topsoil, which had the highest available water content. In general, responses to the climate scenarios differed significantly among the native species which suggest that future climate scenarios of increasing drought might affect not only seedling recruitment but also diversity and structure of native plant communities. The use of waste materials from mining operations as growth media could be an alternative to the limited topsoil. However, in the early stages of plant establishment successful seedling recruitment can be challenging in the absence of water. These limitations could be overcome by using soil amendments but the cost associated to these solutions at large landscape scales needs to be assessed and proven to be economically feasible.

Assessment of Rock Magnetic Parameters for Fly Ash Pollution Screening in Topsoil of the Deccan Trap Basalt Area, India

NASA Astrophysics Data System (ADS)

Blaha, U.; Basavaiah, N.; Das, P. K.; Deenadayalan, K.

2012-04-01

Rock magnetic parameters of highly magnetic topsoil of the Deccan Trap basalt area are evaluated for their suitability for efficient environmental magnetic pollution screening. Parameters, such as magnetic susceptibility (χ), frequency dependence of magnetic susceptibility (κ fd%), anhysteretic remanent magnetization (ARM), saturation isothermal remanent magnetization (SIRM), soft isothermal remanent magnetization (Soft IRM), as well as thermo-magnetic analysis (κ-T) are compared and assessed for best depiction of topsoil contamination due to ash deposition around the Nashik thermal power station (NTPS). Fifty-five topsoil samples, collected along north-south and west-east stretching transects of 24 km length, are the basis for evaluation of the specific ash distribution pattern around the plant and its adjacent ash pond. Similar decline of the magnetic signals with increasing distance from the point source is observed in the concentration dependent magnetic parameters and can be modeled. The magnetic grain size parameters instead reveal increasing trends with increasing distance. Verwey-transition and Hopkinson peak obtained from κ-T analyses demonstrate to be important parameters to prove fly ash accumulation in soils of basaltic origin. The importance of magnetic parameters for indirect tracing of pollutants, such as heavy metals, is shown by Pb, Zn and Cu data, revealing similar distribution pattern as obtained from the concentration dependent magnetic parameters. Confirmation of the presence of a very high amount of ash particles in the vicinity of the NTPS and a low number of particles in more distant areas is provided by scanning electron microscopy (SEM) on quantitatively extracted magnetic particles at 5.5 km and 11.9 km distance in eastern direction. The investigation demonstrates that the majority of the rock magnetic parameters has the potential to be successfully applied in environmental magnetic studies in areas with high magnetic background values.

ESTABLISHMENT AND EVALUATION OF SWITCHGRASS ON RECLAIMED MINE SOIL [English

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lang, David; Shankle, Brandon; Oswalt, Ernest

Switchgrass (Panicum virgatum L.) is a native warm season perennial grass that has productive potential of up to 20 Mg ha-1 of biomass and it persists for decades when harvested once per year. Switchgrass provides excellent ground cover and soil stabilization once established and contributes to soil sequestration of new carbon. Slow establishment on newly reclaimed soil, however, provides for significant erosive opportunities thereby requiring initial soil stabilization with a cover crop. Several planting options were evaluated on two topsoil substitute soils. The planting options included: 1) an existing stand of bermudagrass (Cynodon dactylon L.) that was killed with glyphosatemore » followed by disking in red oxidized topsoil substitute and prime farmland topsoil respread in 2007, 2) red oxidized topsoil substitute was seeded directly with switchgrass, 3) browntop millet (Panicum ramosum) was established with switchgrass, 4) or switchgrass was established in senescing browntop millet or wheat without tillage. Switchgrass was successfully established into a bermudagrass sod that had been killed with herbicides and disked as well as into a senescing stand of browntop millet or wheat. Significant soil erosion occurred on the disked area in 2008 leading to considerable repair work followed by planting wheat. Disked areas that did not erode had an excellent stand of switchgrass with 23.3 plants m-2 in November, 2008. Eroded areas replanted in April, 2009 into senescing wheat had 46 plants m-2 by July, 2009. The area planted directly into newly respread soil in May, 2009 was eroded severely by a 75 mm thunderstorm and was repaired, disked and replanted to switchgrass and browntop millet. Switchgrass seeded with browntop millet had a sparse switchgrass stand and was replanted to switchgrass in August, 2009. Rainfall volumes from August, 2009 to October, 2009 totaled 750 mm, but new erosion damage in areas successfully planted to switchgrass has been minimal.« less

Landscape metrics as functional traits in plants: perspectives from a glacier foreland

PubMed Central

Dainese, Matteo; Krüsi, Bertil O.; McCollin, Duncan

2017-01-01

Spatial patterns of vegetation arise from an interplay of functional traits, environmental characteristics and chance. The retreat of glaciers offers exposed substrates which are colonised by plants forming distinct patchy patterns. The aim of this study was to unravel whether patch-level landscape metrics of plants can be treated as functional traits. We sampled 46 plots, each 1 m × 1 m, distributed along a restricted range of terrain age and topsoil texture on the foreland of the Nardis glacier, located in the South-Eastern Alps, Italy. Nine quantitative functional traits were selected for 16 of the plant species present, and seven landscape metrics were measured to describe the spatial arrangement of the plant species’ patches on the study plots, at a resolution of 1 cm × 1 cm. We studied the relationships among plant communities, landscape metrics, terrain age and topsoil texture. RLQ-analysis was used to examine trait-spatial configuration relationships. To assess the effect of terrain age and topsoil texture variation on trait performance, we applied a partial-RLQ analysis approach. Finally, we used the fourth-corner statistic to quantify and test relationships between traits, landscape metrics and RLQ axes. Floristically-defined relevé clusters differed significantly with regard to several landscape metrics. Diversity in patch types and size increased and patch size decreased with increasing canopy height, leaf size and weight. Moreover, more compact patch shapes were correlated with an increased capacity for the conservation of nutrients in leaves. Neither plant species composition nor any of the landscape metrics were found to differ amongst the three classes of terrain age or topsoil texture. We conclude that patch-level landscape metrics of plants can be treated as species-specific functional traits. We recommend that existing databases of functional traits should incorporate these type of data. PMID:28785514

Landscape metrics as functional traits in plants: perspectives from a glacier foreland.

PubMed

Sitzia, Tommaso; Dainese, Matteo; Krüsi, Bertil O; McCollin, Duncan

2017-01-01

Spatial patterns of vegetation arise from an interplay of functional traits, environmental characteristics and chance. The retreat of glaciers offers exposed substrates which are colonised by plants forming distinct patchy patterns. The aim of this study was to unravel whether patch-level landscape metrics of plants can be treated as functional traits. We sampled 46 plots, each 1 m × 1 m, distributed along a restricted range of terrain age and topsoil texture on the foreland of the Nardis glacier, located in the South-Eastern Alps, Italy. Nine quantitative functional traits were selected for 16 of the plant species present, and seven landscape metrics were measured to describe the spatial arrangement of the plant species' patches on the study plots, at a resolution of 1 cm × 1 cm. We studied the relationships among plant communities, landscape metrics, terrain age and topsoil texture. RLQ-analysis was used to examine trait-spatial configuration relationships. To assess the effect of terrain age and topsoil texture variation on trait performance, we applied a partial-RLQ analysis approach. Finally, we used the fourth-corner statistic to quantify and test relationships between traits, landscape metrics and RLQ axes. Floristically-defined relevé clusters differed significantly with regard to several landscape metrics. Diversity in patch types and size increased and patch size decreased with increasing canopy height, leaf size and weight. Moreover, more compact patch shapes were correlated with an increased capacity for the conservation of nutrients in leaves. Neither plant species composition nor any of the landscape metrics were found to differ amongst the three classes of terrain age or topsoil texture. We conclude that patch-level landscape metrics of plants can be treated as species-specific functional traits. We recommend that existing databases of functional traits should incorporate these type of data.

Tillage and crop residue management methods had minor effects on the stock and stabilization of topsoil carbon in a 30-year field experiment.

PubMed

Singh, Pooja; Heikkinen, Jaakko; Ketoja, Elise; Nuutinen, Visa; Palojärvi, Ansa; Sheehy, Jatta; Esala, Martti; Mitra, Sudip; Alakukku, Laura; Regina, Kristiina

2015-06-15

We studied the effects of tillage and straw management on soil aggregation and soil carbon sequestration in a 30-year split-plot experiment on clay soil in southern Finland. The experimental plots were under conventional or reduced tillage with straw retained, removed or burnt. Wet sieving was done to study organic carbon and soil composition divided in four fractions: 1) large macroaggregates, 2) small macroaggregates, 3) microaggregates and 4) silt and clay. To further estimate the stability of carbon in the soil, coarse particulate organic matter, microaggregates and silt and clay were isolated from the macroaggregates. Total carbon stock in the topsoil (equivalent to 200 kg m(-2)) was slightly lower under reduced tillage (5.0 kg m(-2)) than under conventional tillage (5.2 kg m(-2)). Reduced tillage changed the soil composition by increasing the percentage of macroaggregates and decreasing the percentage of microaggregates. There was no evidence of differences in the composition of the macroaggregates or carbon content in the macroaggregate-occluded fractions. However, due to the higher total amount of macroaggregates in the soil, more carbon was bound to the macroaggregate-occluded microaggregates in reduced tillage. Compared with plowed soil, the density of deep burrowing earthworms (Lumbricus terrestris) was considerably higher under reduced tillage and positively associated with the percentage of large macroaggregates. The total amount of microbial biomass carbon did not differ between the treatments. Straw management did not have discernible effects either on soil aggregation or soil carbon stock. We conclude that although reduced tillage can improve clay soil structure, generally the chances to increase topsoil carbon sequestration by reduced tillage or straw management practices appear limited in cereal monoculture systems of the boreal region. This may be related to the already high C content of soils, the precipitation level favoring decomposition and aggregate turnover in the winter with topsoil frost. Copyright © 2015. Published by Elsevier B.V.

Effects of flooding on phosphorus and iron mobilization in highly weathered soils: Short-term effects and mechanisms

NASA Astrophysics Data System (ADS)

Maranguit, Deejay

2017-04-01

The strong affinity of phosphorus (P) to iron (Fe) oxides and hydroxides in highly weathered tropical soils limits P availability and therefore plant productivity. In flooded soils, however, P fixed by Fe oxides and hydroxides can be released and transformed to a more available form because of Fe3+ reduction to Fe2+. These P dynamics in flooded soils are well documented for rice paddies. Such effects are much less studied in other land-use types under the influence of seasonal flooding, especially in the tropics during heavy monsoon rains. The aim of this study was to investigate the mobilization of P during flooding leading to anaerobic conditions in topsoil and subsoil horizons depending on land-use type. Samples were collected in highly weathered soils from four replicate sites under natural rainforest, jungle rubber, rubber and oil palm plantations in Sumatra, Indonesia. Topsoil and subsoil were taken to ensure a wide range of soil organic matter (SOM) and P contents. Soils were incubated under anaerobic, flooded conditions at 30 ± 1 oC for 60 days. Our results confirmed the hypothesis that soil flooding mobilizes P and increases P availability. Two distinct and opposite phases, however, were observed upon flooding. During the first three weeks of flooding, the dissolved P (DP) concentration peaked, simultaneously with a peak of dissolved Fe2+ (DFe2+) and dissolved organic carbon (DOC) in the soil solution. After three weeks, P availability in soils decreased, although Fe-P and available P did not reach initial, pre-flooding levels. Accordingly, Fe dissolution and P mobilization were reversible processes. Furthermore, land-use type influenced the impacts of flooding on P and Fe forms mainly in the topsoil, where P dissolution and availability were generally higher under forest and, to a lesser extent, under jungle rubber. A positive correlation between DOC and DFe2+ (R2 = 0.42) in topsoil indicates that the intensity of microbially-mediated Fe3+ reduction is limited by the amount of available carbon (C) as an energy source for microorganisms. Moreover, microbial mineralization of organic P from SOM also increases P availability, and this process requires available C. This interpretation was supported by the strong correlation (R2 = 0.58) between available P and DOC, as well as between DP and DOC (R2 = 0.56) in topsoil. The increasing soil solution pH in topsoil and subsoil after flooding of all land-use types may also influence the P release over time. In summary, the increase of available P and DP during flooding is due to three main mechanisms: (1) P release via the microbially-mediated reductive dissolution of Fe3+ oxides; (2) P release during SOM mineralization and (3) solubility of Fe phosphate due to increasing pH. These mechanisms are relevant not only in riparian areas, where flooding occurs, but also in well-drained soil that is partly waterlogged after regular heavy rainfalls during the wet season. Likewise, the P cycle turnover is faster in compacted, often anaerobic plantation soils. Here, more P is pumped by the vegetation and then removed from plantations due to yield export.

Characteristics of organic matter fractions separated by wet-sieving and differences in density from five soils of different pedogenesis under mature beech forest.

NASA Astrophysics Data System (ADS)

Vormstein, Svendja; Kaiser, Michael; Ludwig, Bernard

2017-04-01

Forest top- and subsoil account for approximately 70 % of the organic C (OC) globally stored in soil reasoning their large importance for terrestrial ecosystem services such as the mitigation of climate change. In contrast to forest topsoil, there is much less information about the decomposition and stabilization of organic matter (OM) in subsoil. Therefore, we sampled the pedogenetic horizons of five soils under mature beech forest developed on different parent material (i.e. Tertiary Sand, Loess, Basalt, Lime Stone, Red Sandstone) down to the bedrock. The bulk soil samples were characterized for texture, oxalate and dithionite soluble Fe and Al, pH, OC, microbial biomass C and basal respiration (cumulative CO2 emission after 7 and 14 days). Furthermore, we analyzed aggregate size fractions separated by wet-sieving (i.e. >1000 µm, 1000-250 µm, 250-53 µm, <53 µm) and density fractions separated using NaPT (i.e. light, occluded light, and heavy fraction) from the soil horizon specific samples. The OC of the topsoil (Ah horizon) on Lime Stone and Red Sandstone was predominately stored in the larger macro-aggregates (>1000 µm). In contrast, the major part of the topsoil OC on Basalt and Tertiary Sand was found in the smaller macro-aggregates (1000-250 µm). For the topsoil samples, we found that the basal respiration as well as the microbial biomass C were positively correlated (p ≤0.05) with the OC amounts associated with the free and occluded light fraction and with the macro-aggregates (1000-250 µm) and micro-aggregates (250-53 µm) suggesting these fractions to store the major part of the easily decomposable OM. The OC amount associated with the heavy fraction and the fraction <53 µm was correlated with the contents of oxalate and dithionite soluble Fe and Al suggesting interactions between organic compounds and Fe- and Al-oxides to be highly important for the OM stabilization in forest topsoil. In the subsoil (horizons below the Ah), the contribution of the OC associated with the aggregate size fractions <250 µm to the OC stored in the subsoil increased with depth. The OC contents associated with the free and occluded light as well as the heavy fraction and with the aggregate size fractions >53 µm were positively correlated with basal respiration and the microbial biomass C. This suggests, in contrast to the topsoil, the easily decomposable OM to be distributed more homogeneously among fractions. Only the OC content of the <53 µm fraction showed positive correlations to soil mineral characteristics such as the contents of clay oxalate and dithionite soluble Fe or Al and no relationship to the basal respiration and microbial biomass C. This indicates the OM associated with this fraction to be most diagnostic for the amount of OC stabilized against microbial decay in the subsoil and interactions between OM and oxides as well as layer silicates to be relevant stabilization mechanisms. The results point toward similar OM stabilization mechanisms in the analysed forest top- and subsoils but revealed differences in the distribution of easily decomposable OM within the soil matrix.

Spatial distribution of topsoil magnetic susceptibility in Sawahlunto City, West Sumatera

NASA Astrophysics Data System (ADS)

Afdal; Wahyuni, E. S.

2018-03-01

A research to determine the spatial distribution of top soil magnetic suceptibility at Sawahlunto City, West Sumatra has been conducted. The top soil samples were taken at four locations ie the downtown area, the steam power plant area, the agricultural area, and coal mine area. At each location, the soil samples were taken at 10 points at a depth of 20 cm. Magnetic susceptibility were measured using Bartington MS2B Magnetic Susceptibility Meter. The topsoil samples from Sawahlunto city have relatively low average value of the magnetic susceptibility that is 67.0×10-8 m3/kg. The magnetic susceptibility of topsoil samples from downtown area have the average and the highest value of magnetic susceptibility (100.6×10-8 and 259.9×10-8 m3/kg), and followed by sample from the steam power plant area (98.4×10-8 and 258.0×10-8 m3/kg), the agricultural area (56.2×10-8 and 83.7×10-8 m3/kg), and coal mine area (12.9×10-8 and 26.8×10-8 m3/kg). Soil samples from the steam power plant area have the widest range of magnetic susceptibility value range from 0.3 × 10-8 to 258.0 × 10-8 m3/kg.

Coke industry and steel metallurgy as the source of soil contamination by technogenic magnetic particles, heavy metals and polycyclic aromatic hydrocarbons.

PubMed

Rachwał, Marzena; Magiera, Tadeusz; Wawer, Małgorzata

2015-11-01

Application of integrated magnetic, geochemical and mineralogical methods for qualitative and quantitative assessment of forest topsoils exposed to the industrial emissions was the objective of this manuscript. Volume magnetic susceptibility (κ) in three areas of southern Poland close to the coke and metallurgical plants was measured directly in the field. Representative topsoil samples were collected for further chemical and mineralogical analyses. Topsoil magnetic susceptibility in the studied areas depended mainly on the content of technogenic magnetic particles (TMPs) and decreased downwind at increasing distance from the emitters. In the vicinity of coking plants a high amount of polycyclic aromatic hydrocarbons (PAHs) was observed, especially the most carcinogenic ones with four- and five-member rings. No significant concentration of TMPs (estimated on the base of κ values) and heavy metals (HM) was observed in area where the coke plant was the only pollution source. In areas with both coke and metallurgical industry, higher amounts of TMPs, PAHs and HM were detected. Morphological and mineralogical analyses of TMPs separated from contaminated soil samples revealed their high heterogeneity in respect of morphology, grain size, mineral and chemical constitution. Pollution load index and toxicity equivalent concentration of PAHs used for soil quality assessment indicated its high level of pollution. Copyright © 2014 Elsevier Ltd. All rights reserved.

Vegetation of waste disposal areas at a coal-fired power plant in Kansas. [Agropyron elongatum, Festuca arundinacea, Melilotus officinalis, Echinochloa crusgalli, Populus deltoides, Juniperus virginiana

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mulhern, D.W.; Robel, R.J.; Furness, J.C.

Disposal of scrubber sludge and fly ash waste from coal-fired power plants is a costly problem for utilities. Current regulations call for the retired waste areas to be covered with topsoil, then seeded to produce a protective vegetative cap. We conducted field tests over a 3-yr period to determine if a vegetative cover could be established without first adding topsoil to waste sites. Seven herbaceous and six tree species were planted on scrubber sludge and bottom ash sites. These substrates were first amended with fertilizer, and then hay, woodchips, or cow (Bos taurus) manure. The bottom ash was not capablemore » of supporting vegetative growth, even with amendment. Tall wheatgrass (Agropyron elongatum, (Host) Beauv.), tall fescue (Festuca arundinacea Schreb.), yellow sweet clover (Melilotus officinalis Lam.), and Japanese millet (Echinochloa crusgalli (L.) Beauv.) grew well on scrubber sludge, as did eastern cottonwood (Populus deltoides Marsh.) and eastern red cedar trees (Juniperus virginiana L.). Generally, herbaceous plants grew best on scrubber sludge to which manure and fertilizer were added, the trees survived and grew best on scrubber sludge amended with woodchips and fertilizer. This study demonstrates that a good vegetative cover can be produced on scrubber sludge waste areas without first covering them with topsoil.« less

Using the natural biodegradation potential of shallow soils for in-situ remediation of deep vadose zone and groundwater.

PubMed

Avishai, Lior; Siebner, Hagar; Dahan, Ofer; Ronen, Zeev

2017-02-15

In this study, we examined the ability of top soil to degrade perchlorate from infiltrating polluted groundwater under unsaturated conditions. Column experiments designed to simulate typical remediation operation of daily wetting and draining cycles of contaminated water amended with an electron donor. Covering the infiltration area with bentonite ensured anaerobic conditions. The soil remained unsaturated, and redox potential dropped to less than -200mV. Perchlorate was reduced continuously from ∼1150mg/L at the inlet to ∼300mg/L at the outlet in daily cycles. Removal efficiency was between 60 and 84%. No signs of bioclogging were observed during three operation months although occasional iron reduction observed due to excess electron donor. Changes in perchlorate reducing bacteria numbers were inferred from an increased in pcrA gene abundances from ∼10 5 to 10 7 copied per gram at the end of the experiment indicating the growth of perchlorate-reducing bacteria. We proposed that the topsoil may serve as a bioreactor to treat high concentrations of perchlorate from the contaminated groundwater. The treated water that infiltrates from the topsoil through the vadose zone could be used to flush perchlorate from the deep vadose zone into the groundwater where it is retrieved again for treatment in the topsoil. Copyright © 2016 Elsevier B.V. All rights reserved.

Soil characteristics of landslides on Mount Elgon (Uganda): implications for estimating their age

NASA Astrophysics Data System (ADS)

Van Eynde, Elise; Dondeyne, Stefaan; Isabirye, Moses; Deckers, Jozef; Poesen, Jean

2017-04-01

The slopes of Mount Elgon, a complex volcano at the border between Uganda and Kenya, are frequently affected by landslides with disastrous effects on the livelihood of its population. Since local people greatly depend on the land for crop production, we examined if and how fast physico-chemical characteristics in landslide scars recover. A chronosequence of 18 landslides covering a period of 103 years was sampled in order to explore differences between topsoil within and outside landslide scars. For each landslide, two topsoil samples were taken within the landslide and two in nearby undisturbed soils to compare their physico-chemical characteristics. No differences were found for available P, Ca2+, Mg2+ content or for the fine earth texture. Recent landslides had however lower content of soil organic carbon (OC) and K+, and higher content of rock fragments and Na+ than the adjacent soils. Soil OC content increased significantly with age and reached levels of the corresponding undisturbed soils after ca. 60 years. Older landslides had even higher OC contents than soils adjacent to the landslide. Hence landslide scars act as local carbon sink. We suggest that the occurrence of rock fragments in the topsoil is a useful indicator for mapping past landslides. Moreover, the difference in soil OC content between landslide scars and adjacent soil could be used for estimating the age of landslides in data-poor regions.

The response of earthworms (Eisenia fetida) and soil microbes to the crumb rubber material used in artificial turf fields.

PubMed

Pochron, Sharon T; Fiorenza, Andrew; Sperl, Cassandra; Ledda, Brianne; Lawrence Patterson, Charles; Tucker, Clara C; Tucker, Wade; Ho, Yuwan Lisa; Panico, Nicholas

2017-04-01

Municipalities have been replacing grass fields with artificial turf, which uses crumb rubber infill made from recycled tires. Crumb rubber contains hydrocarbons, organic compounds, and heavy metals. Water runoff from crumb rubber fields contains heavy metals. These components can damage the environment. We contaminated topsoil with new crumb rubber and measured its impact on earthworms and soil microbes. Specifically, we compared soil microbe activity and earthworm health, survivorship, and longevity in heat and light stress under two soil regimes: clean topsoil and clean topsoil contaminated with crumb rubber. We then characterized levels of metals, nutrients, and micronutrients of both soil treatments and compared those to published New York soil background levels and to levels set by the New York State Department of Environmental Conservation (DEC) as remediation goals. We found that: 1) contaminated soil did not inhibit microbial respiration rates, 2) earthworm survivorship was not impacted by exposure to contaminated soil, 3) earthworms' ability to cope with heat and light stress remained unchanged after living in contaminated soil, but 4) earthworms living in contaminated soil gained 14% less body weight than did earthworms living in uncontaminated soil. We also found that, with the exception of zinc, heavy metals in our contaminated soil did not exceed the background levels found throughout New York State or the remediation targets set by the DEC. Published by Elsevier Ltd.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schuman, G.E.; Stahl, P.D.; Williams, S.E.

Reestablishment of Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis) on mined lands has been difficult in the past even though it is widespread in the western US. Its reestablishment on mined lands has recently become law where wildlife is one of the post-mining land uses and it represented the primary premining shrub species. One hypothesis thought to contribute to its difficult reestablishment is the reduce lack of mycorrhizae inoculum present in the disturbed topsoil and the resulting effect on the seedling`s ability to extract water from the soil under the arid/semiarid climate of this region. A greenhouse study was conductedmore » to evaluate the effect of mycorrhizae on sagebrush seedling water stress tolerance. Seedling ages evaluated ranged from 30 to 150 days. Seedling survival was greater for mycorrhizal seedlings compared to non-mycorrhizal seedlings when soil moisture tension was {minus}2.5 to {minus}3.8 MPa. At all ages, the degree of soil dryness necessary to cause sagebrush seedling mortality was significantly greater for mycorrhizal than non-mycorrhizal seedlings. Seedling age and mycorrhizal infection exhibited a significant statistical interaction; suggesting that as the sagebrush seedling aged, the benefits of arbuscular mycorrhizae (AM) increased the plants water stress tolerance. These findings lead the authors to conclude that topsoil management that prevents/reduces the loss of AM inoculum in the topsoil will significantly enhance the success of sagebrush establishment on mined lands.« less

Tillage practices and straw-returning methods affect topsoil bacterial community and organic C under a rice-wheat cropping system in central China

NASA Astrophysics Data System (ADS)

Guo, Lijin; Zheng, Shixue; Cao, Cougui; Li, Chengfang

2016-09-01

The objective of this study was to investigate how the relationships between bacterial communities and organic C (SOC) in topsoil (0-5 cm) are affected by tillage practices [conventional intensive tillage (CT) or no-tillage (NT)] and straw-returning methods [crop straw returning (S) or removal (NS)] under a rice-wheat rotation in central China. Soil bacterial communities were determined by high-throughput sequencing technology. After two cycles of annual rice-wheat rotation, compared with CT treatments, NT treatments generally had significantly more bacterial genera and monounsaturated fatty acids/saturated fatty acids (MUFA/STFA), but a decreased gram-positive bacteria/gram-negative bacteria ratio (G+/G-). S treatments had significantly more bacterial genera and MUFA/STFA, but had decreased G+/G- compared with NS treatments. Multivariate analysis revealed that Gemmatimonas, Rudaea, Spingomonas, Pseudomonas, Dyella, Burkholderia, Clostridium, Pseudolabrys, Arcicella and Bacillus were correlated with SOC, and cellulolytic bacteria (Burkholderia, Pseudomonas, Clostridium, Rudaea and Bacillus) and Gemmationas explained 55.3% and 12.4% of the variance in SOC, respectively. Structural equation modeling further indicated that tillage and residue managements affected SOC directly and indirectly through these cellulolytic bacteria and Gemmationas. Our results suggest that Burkholderia, Pseudomonas, Clostridium, Rudaea, Bacillus and Gemmationas help to regulate SOC sequestration in topsoil under tillage and residue systems.

Erodibility of waste (Loess) soils from construction sites under water and wind erosional forces.

PubMed

Tanner, Smadar; Katra, Itzhak; Argaman, Eli; Ben-Hur, Meni

2018-03-01

Excess soils from construction sites (waste soils) become a problem when exposed to soil erosion by water or wind. Understanding waste soil erodibility can contribute to its proper reuse for various surface applications. The general objective of the study was to provide a better understanding of the effects of soil properties on erodibility of waste soils excavated from various depths in a semiarid region under rainfall and wind erosive forces. Soil samples excavated from the topsoil (0-0.3m) and subsoil layers (0.3-0.9 and >1m depths) were subjected to simulated rainfall and wind. Under rainfall erosive forces, the subsoils were more erodible than the topsoil, in contrast to the results obtained under wind erosive forces. Exchangeable sodium percentage was the main factor controlling soil erodibility (K i ) under rainfall, and a significant logarithmic regression line was found between these two parameters. In addition, a significant, linear regression was found between K i and slaking values for the studied soil samples, suggesting that the former can be predicted from the latter. Soil erodibility under wind erosion force was controlled mainly by the dry aggregate characteristics (mean weight diameter and aggregate density): their higher values in the subsoil layers resulted in lower soil erodibility compared to the topsoil. Copyright © 2017 Elsevier B.V. All rights reserved.

Reclamation of zinc-contaminated soil using a dissolved organic carbon solution prepared using liquid fertilizer from food-waste composting.

PubMed

Chiang, Po-Neng; Tong, Ou-Yang; Chiou, Chyow-San; Lin, Yu-An; Wang, Ming-Kuang; Liu, Cheng-Chung

2016-01-15

A liquid fertilizer obtained through food-waste composting can be used for the preparation of a dissolved organic carbon (DOC) solution. In this study, we used the DOC solutions for the remediation of a Zn-contaminated soil (with Zn concentrations up to 992 and 757 mg kg(-1) in topsoil and subsoil, respectively). We then determined the factors that affect Zn removal, such as pH, initial concentration of DOC solution, and washing frequency. Measurements using a Fourier Transform infrared spectrometer (FT-IR) revealed that carboxyl and amide were the major functional groups in the DOC solution obtained from the liquid fertilizer. Two soil washes using 1,500 mg L(-1) DOC solution with a of pH 2.0 at 25°C removed about 43% and 21% of the initial Zn from the topsoil and subsoil, respectively. Following this treatment, the pH of the soil declined from 5.4 to 4.1; organic matter content slightly increased from 6.2 to 6.5%; available ammonium (NH4(+)-N) content increased to 2.4 times the original level; and in the topsoil, the available phosphorus content and the exchangeable potassium content increased by 1.65 and 2.53 times their initial levels, respectively. Copyright © 2015 Elsevier B.V. All rights reserved.

Increased precipitation accelerates soil organic matter turnover associated with microbial community composition in topsoil of alpine grassland on the eastern Tibetan Plateau.

PubMed

Han, Conghai; Wang, Zongli; Si, Guicai; Lei, Tianzhu; Yuan, Yanli; Zhang, Gengxin

2017-10-01

Large quantities of carbon are stored in alpine grassland of the Tibetan Plateau, which is extremely sensitive to climate change. However, it remains unclear whether soil organic matter (SOM) in different layers responds to climate change analogously, and whether microbial communities play vital roles in SOM turnover of topsoil. In this study we measured and collected SOM turnover by the 14 C method in alpine grassland to test climatic effects on SOM turnover in soil profiles. Edaphic properties and microbial communities in the northwestern Qinghai Lake were investigated to explore microbial influence on SOM turnover. SOM turnover in surface soil (0-10 cm) was more sensitive to precipitation than that in subsurface layers (10-40 cm). Precipitation also imposed stronger effects on the composition of microbial communities in the surface layer than that in deeper soil. At the 5-10 cm depth, the SOM turnover rate was positively associated with the bacteria/fungi biomass ratio and the relative abundance of Acidobacteria, both of which are related to precipitation. Partial correlation analysis suggested that increased precipitation could accelerate the SOM turnover rate in topsoil by structuring soil microbial communities. Conversely, carbon stored in deep soil would be barely affected by climate change. Our results provide valuable insights into the dynamics and storage of SOM in alpine grasslands under future climate scenarios.

Modelling increased soil cohesion by plant roots with EUROSEM

NASA Astrophysics Data System (ADS)

de Baets, S.; Poesen, J.; Torri, D.; Salvador, M. P.

2009-04-01

Soil cohesion is an important variable to model soil detachment by runoff (Morgan et al., 1998a). As soil particles are not loose, soil detachment by runoff will be limited by the cohesion of the soil material. It is generally recognized that plant roots contribute to the overall cohesion of the soil. Determination of this increased cohesion and soil roughness however is complicated and measurements of shear strength and soil reinforcement by plant roots are very time- and labour consuming. A model approach offers an alternative for the assessment of soil cohesion provided by plant roots However, few erosion models account for the effects of the below-ground biomass in their calculation of erosion rates. Therefore, the main objectives of this study is to develop an approach to improve an existing soil erosion model (EUROSEM) accounting for the erosion-reducing effects of roots. The approach for incorporating the root effects into this model is based on a comparison of measured soil detachment rates for bare and for root-permeated topsoil samples with predicted erosion rates under the same flow conditions using the erosion equation of EUROSEM. Through backwards calculation, transport capacity efficiencies and corresponding soil cohesion values can be assessed for bare and root-permeated topsoils respectively. The results are promising and show that grass roots provide a larger increase in soil cohesion as compared with tap-rooted species and that the increase in soil cohesion is not significantly different under wet and dry soil conditions, either for fibrous root systems or for tap root systems. Relationships are established between measured root density values and the corresponding calculated soil cohesion values, reflecting the effects of roots on the resistance of the topsoil to concentrated flow incision. These relationships enable one to incorporate the root effect into the soil erosion model EUROSEM, through adapting the soil cohesion input value. A scenario analysis performed with EUROSEM for different vegetation treatments, indicates that runoff and soil loss on root-permeated topsoils are slightly higher as compared to fully covered grass fields or harvested grass fields with some plant residue left, but much smaller as compared to bare topsoils. Moreover, when re-vegetating bare soils, roots are responsible for a large part of the reduction in soil loss and runoff by concentrated flow. Hence, this analysis shows that the contribution of roots to soil cohesion is very important for preventing soil loss and reducing runoff volume. The increase in soil shear strength due to the binding effect of roots on soil particles is two orders of magnitude lower as compared with soil reinforcement achieved when roots mobilize their tensile strength during soil shearing and root breakage.

Leaf wax n-alkane patterns from plants and topsoils in the semi-humid to arid southern Caucasus region as a base for paleoenvironmental reconstructions

NASA Astrophysics Data System (ADS)

Bliedtner, Marcel; von Suchodoletz, Hans; Schäfer, Imke; Zech, Roland

2017-04-01

Leaf waxes of terrestrial plants are relatively resistant against degradation and can thus serve as valuable biomarkers that are preserved in various sedimentary archives for millenia. Particularly long-chain n-alkanes are increasingly used for paleoenvironmental studies as they have the great potential to reconstruct past changes in vegetation and climate. However, prior to any robust interpretation of the homologue patterns of long-chain n-alkanes, reference samples from modern vegetation and topsoil material should be investigated at a regional scale, because it has been questioned recently, whether n-alkane patterns are suitable to distinguish between different vegetation types at a global scale (Bush and McInerney, 2013). Apart from Central and Southeastern Europe (Zech et al., 2013; Schäfer et al., 2016), systematic regional studies are still largely lacking. To address this issues and to test the potential of leaf wax n-alkanes for paleoenvironmental studies in the semi-humid to arid southern Caucasus region, we investigated the influence of different vegetation types on the leaf wax signal in modern plants and topsoil material in eastern Georgia. We sampled modern plant and topsoil (0-5 cm) material from (i) grassland sites that included steppe, cultivated grassland and meadows, and (ii) from sites that are dominated by deciduous hornbeam forests. The n-alkane results show distinct differences between samples from sites with grassland and deciduous forests and thus corroborate our results from Central and Southeastern Europe (Schäfer et al., 2016): n-Alkanes from grassland sites are mainly dominated by C31 and C33, while n-alkanes from deciduous sites show high abundances of C27 and C29. Thus, chain-length ratios allow to discriminate between these vegetation types and have a great potential when used for paleoenvironmental reconstructions at least in this region. We updated the existing end-member model of Zech et al. (2013) which accounts for degradation effects and allows semi-quantitative reconstructions of past changes in vegetation types. References Bush, Rosemary T.; McInerney, Francesca A. (2013): Leaf wax n-alkane distributions in and across modern plants. Implications for paleoecology and chemotaxonomy. In: Geochimica et Cosmochimica Acta 117, S. 161-179. Schäfer, Imke; Lanny, Verena; Franke, Jörg; Eglinton, Timothy I.; Zech, Michael; Vysloužilová, Barbora; Zech, Roland (2016): Leaf waxes in litter and topsoils along a European transect. In: SOIL Discuss., S. 1-18. Zech, Roland; Zech, Michael; Marković, Slobodan; Hambach, Ulrich; Huang, Yongsong (2013): Humid glacials, arid interglacials? Critical thoughts on pedogenesis and paleoclimate based on multi-proxy analyses of the loess-paleosol sequence Crvenka, Northern Serbia. In: Palaeoge-ography, Palaeoclimatology, Palaeoecology 387, S. 165-175.

Sorption and desorption of carbamazepine, naproxen and triclosan in a soil irrigated with raw wastewater: estimation of the sorption parameters by considering the initial mass of the compounds in the soil.

PubMed

Durán-Álvarez, Juan C; Prado-Pano, Blanca; Jiménez-Cisneros, Blanca

2012-06-01

In conventional sorption studies, the prior presence of contaminants in the soil is not considered when estimating the sorption parameters because this is only a transient state. However, this parameter should be considered in order to avoid the under/overestimation of the soil sorption capacity. In this study, the sorption of naproxen, carbamazepine and triclosan was determined in a wastewater irrigated soil, considering the initial mass of the compounds. Batch sorption-desorption tests were carried out at two soil depths (0-10 cm and 30-40 cm), using either 10 mM CaCl(2) solution or untreated wastewater as the liquid phase. Data were satisfactorily fitted to the initial mass model. For the two soils, release of naproxen and carbamazepine was observed when the CaCl(2) solution was used, but not in the soil/wastewater system. The compounds' release was higher in the topsoil than in the 30-40 cm soil. Sorption coefficients (K(d)) for CaCl(2) solution tests showed that in the topsoil, triclosan (64.9 L kg(-1)) is sorbed to a higher extent than carbamazepine and naproxen (5.81 and 2.39 L kg(-1), respectively). In the 30-40 cm soil, carbamazepine and naproxen K(d) values (11.4 and 4.41 L kg(-1), respectively) were higher than those obtained for the topsoil, while the triclosan K(d) value was significantly lower than in the topsoil (19.2 L kg(-1)). Differences in K(d) values were found when comparing the results obtained for the two liquid phases. Sorption of naproxen and carbamazepine was reversible for both soils, while sorption of triclosan was found to be irreversible. This study shows the sorption behavior of three pharmaceuticals in a wastewater irrigated soil, as well as the importance of considering the initial mass of target pollutants in the estimation of their sorption parameters. Copyright © 2012 Elsevier Ltd. All rights reserved.

For Better Soil, Let Earthworms Toil.

ERIC Educational Resources Information Center

Swinehart, Rebecca, Ed.

1995-01-01

This activity involves elementary students in investigating how earthworms affect soil fertility. An introduction discusses topsoil loss and the connections between soil and earthworm ecology. Materials needed and step-by-step procedure are provided. (LZ)

Evaluation of ambient dose equivalent rates influenced by vertical and horizontal distribution of radioactive cesium in soil in Fukushima Prefecture.

PubMed

Malins, Alex; Kurikami, Hiroshi; Nakama, Shigeo; Saito, Tatsuo; Okumura, Masahiko; Machida, Masahiko; Kitamura, Akihiro

2016-01-01

The air dose rate in an environment contaminated with (134)Cs and (137)Cs depends on the amount, depth profile and horizontal distribution of these contaminants within the ground. This paper introduces and verifies a tool that models these variables and calculates ambient dose equivalent rates at 1 m above the ground. Good correlation is found between predicted dose rates and dose rates measured with survey meters in Fukushima Prefecture in areas contaminated with radiocesium from the Fukushima Dai-ichi Nuclear Power Plant accident. This finding is insensitive to the choice for modeling the activity depth distribution in the ground using activity measurements of collected soil layers, or by using exponential and hyperbolic secant fits to the measurement data. Better predictions are obtained by modeling the horizontal distribution of radioactive cesium across an area if multiple soil samples are available, as opposed to assuming a spatially homogeneous contamination distribution. Reductions seen in air dose rates above flat, undisturbed fields in Fukushima Prefecture are consistent with decrement by radioactive decay and downward migration of cesium into soil. Analysis of remediation strategies for farmland soils confirmed that topsoil removal and interchanging a topsoil layer with a subsoil layer result in similar reductions in the air dose rate. These two strategies are more effective than reverse tillage to invert and mix the topsoil. Copyright © 2015 Elsevier Ltd. All rights reserved.

Coupled mobilization of dissolved organic matter and metals (Cu and Zn) in soil columns

NASA Astrophysics Data System (ADS)

Zhao, Lu Y. L.; Schulin, Rainer; Weng, Liping; Nowack, Bernd

2007-07-01

Dissolved organic carbon (DOC) is a key component involved in metal displacement in soils. In this study, we investigated the concentration profiles of soil-borne DOC, Cu and Zn at various irrigation rates with synthetic rain water under quasi steady-state conditions, using repacked soil columns with a metal-polluted topsoil and two unpolluted subsoils. Soil solution was collected using suction cups installed at centimeter intervals over depth. In the topsoil the concentrations of DOC, dissolved metals (Zn and Cu), major cations (Ca 2+ and Mg 2+) and anions ( NO3- and SO42-) increased with depth. In the subsoil, the Cu and Zn concentrations dropped to background levels within 2 cm. All compounds were much faster mobilized in the first 4 cm than in the rest of the topsoil. DOC and Cu concentrations were higher at higher flow rates for a given depth, whereas the concentrations of the other ions decreased with increasing flow rate. The decomposition of soil organic matter resulted in the formation of DOC, SO42-, and NO3- and was the main driver of the system. Regression analysis indicated that Cu mobilization was governed by DOC, whereas Zn mobilization was primarily determined by Ca and to a lesser extent by DOC. Labile Zn and Cu 2+ concentrations were well predicted by the NICA-Donnan model. The results highlight the value of high-resolution in-situ measurements of DOC and metal mobilization in soil profiles.

Phosphorus exchangeability and leaching losses from two grassland soils.

PubMed

Sinaj, S; Stamm, C; Toor, G S; Condron, L M; Hendry, T; Di, H J; Cameron, K C; Frossard, E

2002-01-01

Although phosphate phosphorus (P) is strongly sorbed in many soils, it may be quickly transported through the soil by preferential flow. Under flood irrigation, preferential flow is especially pronounced and associated solute losses may be important. Phosphorus losses induced by flood irrigation were investigated in a lysimeter study. Detailed soil chemical analyses revealed that P was very mobile in the topsoil, but the higher P-fixing capacity of the subsoil appeared to restrict P mobility. Application of a dye tracer enabled preferential flow pathways to be identified. Soil sampling according to dye staining patterns revealed that exchangeable P was significantly greater in preferential flow areas as compared with the unstained soil matrix. This could be partly attributed to the accumulation of organic carbon and P, together with enhanced leaching of Al- and Fe-oxides in the preferential flow areas, which resulted in reduced P sorption. The irrigation water caused a rapid hydrologic response by displacement of resident water from the subsoil. Despite the occurrence of preferential flow, most of the outflowing water was resident soil water and very low in P. In these soils the occurrence of preferential flow per se is not sufficient to cause large P losses even if the topsoil is rich in P. It appears that the P was retained in lower parts of the soil profile characterized by a very high P-fixing capacity. This study demonstrates the risks associated with assessing potential P losses on the basis of P mobility in the topsoil alone.

Maps of heavy metals in the soils of the European Union and proposed priority areas for detailed assessment.

PubMed

Tóth, Gergely; Hermann, Tamás; Szatmári, Gábor; Pásztor, László

2016-09-15

Soil contamination is one of the greatest concerns among the threats to soil resources in Europe and globally. Despite of its importance there was only very course scale (1/5000km(2)) data available on soil heavy metal concentrations prior to the LUCAS topsoil survey, which had a sampling density of 200km(2). Based on the results of the LUCAS sampling and auxiliary information detailed and up-to-date maps of heavy metals (As, Cd, Cr, Cu, Hg, Pb, Zn, Sb, Co and Ni) in the topsoil of the European Union were produced. Using the maps of heavy metal concentration in topsoil we made a spatial prediction of areas where local assessment is suggested to monitor and eventually control the potential threat from heavy metals. Most of the examined elements remain under the corresponding threshold values in the majority of the land of the EU. However, one or more of the elements exceed the applied threshold concentration on 1.2Mkm(2), which is 28.3% of the total surface area of the EU. While natural backgrounds might be the reason for high concentrations on large proportion of the affected soils, historical and recent industrial and mining areas show elevated concentrations (predominantly of As, Cd, Pb and Hg) too, indicating the magnitude of anthropogenic effect on soil quality in Europe. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Levels and ecological risk assessment of metals in soils from a typical e-waste recycling region in southeast China.

PubMed

Zhao, Weituo; Ding, Lei; Gu, Xiaowen; Luo, Jie; Liu, Yunlang; Guo, Li; Shi, Yi; Huang, Ting; Cheng, Shenggao

2015-11-01

Due to the high threat to human health and the ecosystem from metals, the levels and distribution of As, Hg, Cr, Co, Ni, Cu, Zn, Cd, Pb, Mn, V, Sn, Sb, Li and Be in various layers of soil from an e-waste recycling area in Guiyu, China were investigated. The extent of pollution from the metals in soil was assessed using enrichment factors (EFs) and the Nemerow pollution index (P N ). To determine the metals' integrated potential ecological risks, the potential ecological risk index (RI) was chosen. The concentrations of Hg, Ni, Cu, Cd, Pb, Sn and Sb were mainly enriched in the topsoil. EF values (2-5) of the elements Hg, Co, Ni, Zn, Sn, Li and Be revealed their moderate enrichment status in the topsoil, derived from e-waste recycling activities. P N presented a decreasing trend in different layers in the order topsoil (0-20 cm) > deep soil (100-150 cm) > middle soil (50-100 cm) > shallow soil (20-50 cm). With higher potential ecological risk factor (E(i)), Hg and Cd are the main contributors to the potential ecological risk. With respect to the RI, all the values in soil from the study area exceeded 300, especially for the soil at sites S2, S4, S5, S7 and S8, where RI was greater than 600. Therefore, immediate remediation of the contaminated soil is necessary to prevent the release of metals and potential ecological harm.

30 CFR 816.102 - Backfilling and grading: General requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... organic material shall be removed from the area. (2) The topsoil on the area shall be removed, segregated... may be allowed by the regulatory authority where— (1) Needed to conserve soil moisture, ensure...

30 CFR 816.102 - Backfilling and grading: General requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... organic material shall be removed from the area. (2) The topsoil on the area shall be removed, segregated... may be allowed by the regulatory authority where— (1) Needed to conserve soil moisture, ensure...

30 CFR 816.102 - Backfilling and grading: General requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... organic material shall be removed from the area. (2) The topsoil on the area shall be removed, segregated... may be allowed by the regulatory authority where— (1) Needed to conserve soil moisture, ensure...

30 CFR 816.102 - Backfilling and grading: General requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... organic material shall be removed from the area. (2) The topsoil on the area shall be removed, segregated... may be allowed by the regulatory authority where— (1) Needed to conserve soil moisture, ensure...

30 CFR 816.102 - Backfilling and grading: General requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... organic material shall be removed from the area. (2) The topsoil on the area shall be removed, segregated... may be allowed by the regulatory authority where— (1) Needed to conserve soil moisture, ensure...

Geochemical variability of soils and biogeochemical variability of plants in the Piceance Basin, Colorado

USGS Publications Warehouse

Tuttle, M.L.; Severson, R.C.; Dean, W.E.; Klusman, R.W.

1986-01-01

Geochemical baselines for native soils and biogeochemical baselines for plants in the Piceance basin provide data that can be used to assess geochemical and biogeochemical effects of oil-shale development, monitor changes in the geochemical and biogeochemical environment during development, and assess the degree of success of rehabilitation of native materials after development. Baseline values for 52 properties in native soils, 15 properties in big sagebrush, and 13 properties in western wheatgrass were established. Our Study revealed statistically significant regional variations of the following properties across the basin: in soil&-aluminum, cobalt, copper, iron, manganese, sodium, nickel, phosphorus, lead, scandium, titanium, vanadium, zinc, organic and total carbon, pH, clay, dolomite, sodium feldspar, and DTPA-extractable calcium, cadmium, iron, potassium, manganese, nickel, phosphorus, yttrium, and zinc; in big sagebrush-barium, calcium, copper, magnesium, molybdenum, sodium, strontium, zinc, and ash; and in western wheatgrass-boron, barium, calcium, magnesium, manganese, molybdenum, strontium, zinc, and ash. These variations show up as north-south trends across the basin, or they reflect differences in elevation, hydrology, and soil parent material. Baseline values for properties that do not have statistically significant regional variations can be represented by geometric means and deviations calculated from all values within the basin. Chemical and mineralogical analyses of soil and chemical analyses of western wheatgrass samples from Colorado State University's experimental revegetation plot at Anvil Points provide data useful in assessing potential effects on soil and plant properties when largescale revegetation operations begin. The concentrations of certain properties are related to the presence of topsoil over spent shale in the lysimeters. In soils, calcium, fluorine, lithium, magnesium, sodium, phosphorus, strontium, carbonate and total carbon, and DTPA-extractable boron, copper, iron, magnesium, and nickel have lower concentrations in topsoil than in the spent oil shale; whereas, silicon, titanium, ytterbium, clay, quartz, and DTPA-extractable potassium have greater concentrations in the topsoil than in the spent oil shale. In western wheatgrass, molybdenum has a lower concentration in grasses growing on the topsoil than in grasses on the spent oil shale; whereas, barium, calcium, manganese, strontium, zinc, and ash have greater concentrations in grasses growing on the topsoil than on the spent oil shale. When compared to baseline values, soils in the revegetation plot are significantly higher in concentrations of lead, zinc, organic and total carbon, and DTP A-extractable cadmium, iron, manganese, nickel, phosphorus, and zinc. Whereas, western wheatgrass grown within the revegetation plot has concentrations which fall within the baseline values established in the regional study. The equations used in predicting concentrations of elements in plants from native and altered sites are cumbersome because of the large number of variables required to adequately predict expected concentrations and are of limited use because many explained only a small proportion of the total variation.

Tree-Substrate Water Relations and Root Development in Tree Plantations Used for Mine Tailings Reclamation.

PubMed

Guittonny-Larchevêque, Marie; Bussière, Bruno; Pednault, Carl

2016-05-01

Tree water uptake relies on well-developed root systems. However, mine wastes can restrict root growth, in particular metalliferous mill tailings, which consist of the finely crushed ore that remains after valuable metals are removed. Thus, water stress could limit plantation success in reclaimed mine lands. This study evaluates the effect of substrates varying in quality (topsoil, overburden, compost and tailings mixture, and tailings alone) and quantity (50- or 20-cm-thick topsoil layer vs. 1-m plantation holes) on root development and water stress exposure of trees planted in low-sulfide mine tailings under boreal conditions. A field experiment was conducted over 2 yr with two tree species: basket willow ( L.) and hybrid poplar ( Moench × A. Henry). Trees developed roots in the tailings underlying the soil treatments despite tailings' low macroporosity. However, almost no root development occurred in tailings underlying a compost and tailings mixture. Because root development and associated water uptake was not limited to the soil, soil volume influenced neither short-term (water potential and instantaneous transpiration) nor long-term (δC) water stress exposure in trees. However, trees were larger and had greater total leaf area when grown in thicker topsoil. Despite a volumetric water content that always remained above permanent wilting point in the tailings colonized by tree roots, measured foliar water potentials at midday were lower than drought thresholds reported for both tested tree species. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

C principal pools and fluxes in the field agroecosystems of Juriev-Polskiy Opolie

NASA Astrophysics Data System (ADS)

Atenbekov, Ramiz; Yashin, Ivan; Vasenev, Ivan

2017-04-01

There are results of 7-year (2010-2016) investigation of the Podzols and Podzoluvisols genesis, dynamics and soil organic carbon (SOC) pools in the representative agrolandscapes of the Yuryev-Polish plain (Yaroslavl region) with estimated environmental risks, including topsoil CO2 emission and the water-soluble organic substances (WSOS) profile and lateral fluxes in conditions of different land-use practice and microclimate conditions. A set of regional stationary plots has been investigated in 5 soil-ecological catenas with different level of erosion and hydromorphic processes. Soil organic matter is poorly fixed to the mineral matrix and has high migration ability, as shown by the sorption lysimeter and model experiments with weak solutions of oxalic acid and water. The total content of soil organic carbon varies in the range of 1.4% to 2.8% in topsoil of the investigated arable Podzols and Podzoluvisols. SOC fractional-group average composition indicates the presence of 37% of fulvic acids and 41% of gumins. The most available for soil microorganisms, enhancing CO2 emission, principal water-soluble organic substances accumulate in the topsoil A1 horizon, whereas the eluvial horizon E serves as a transit barrier to their profile migration and layer of active lateral migration. Modern climate and land-use changes play important role in the spatial-temporal variability of dominant soil GHG fluxes in these landscapes that determines the rising interest in the agroecological monitoring here to develop basic elements of the climate-smart farming systems with sustainable grass, winter wheat and barley production.

Relationships between Heavy Metal Concentrations in Roadside Topsoil and Distance to Road Edge Based on Field Observations in the Qinghai-Tibet Plateau, China

PubMed Central

Yan, Xuedong; Gao, Dan; Zhang, Fan; Zeng, Chen; Xiang, Wang; Zhang, Man

2013-01-01

This study investigated the spatial distribution of copper (Cu), zinc (Zn), cadmium (Cd), lead (Pb), chromium (Cr), cobalt (Co), nickel (Ni) and arsenic (As) in roadside topsoil in the Qinghai-Tibet Plateau and evaluated the potential environmental risks of these roadside heavy metals due to traffic emissions. A total of 120 topsoil samples were collected along five road segments in the Qinghai-Tibet Plateau. The nonlinear regression method was used to formulize the relationship between the metal concentrations in roadside soils and roadside distance. The Hakanson potential ecological risk index method was applied to assess the degrees of heavy metal contaminations. The regression results showed that both of the heavy metals’ concentrations and their ecological risk indices decreased exponentially with the increase of roadside distance. The large R square values of the regression models indicate that the exponential regression method can suitably describe the relationship between heavy metal accumulation and roadside distance. For the entire study region, there was a moderate level of potential ecological risk within a 10 m roadside distance. However, Cd was the only prominent heavy metal which posed potential hazard to the local soil ecosystem. Overall, the rank of risk contribution to the local environments among the eight heavy metals was Cd > As > Ni > Pb > Cu > Co > Zn > Cr. Considering that Cd is a more hazardous heavy metal than other elements for public health, the local government should pay special attention to this traffic-related environmental issue. PMID:23439515

Topological data analysis (TDA) applied to reveal pedogenetic principles of European topsoil system.

PubMed

Savic, Aleksandar; Toth, Gergely; Duponchel, Ludovic

2017-05-15

Recent developments in applied mathematics are bringing new tools that are capable to synthesize knowledge in various disciplines, and help in finding hidden relationships between variables. One such technique is topological data analysis (TDA), a fusion of classical exploration techniques such as principal component analysis (PCA), and a topological point of view applied to clustering of results. Various phenomena have already received new interpretations thanks to TDA, from the proper choice of sport teams to cancer treatments. For the first time, this technique has been applied in soil science, to show the interaction between physical and chemical soil attributes and main soil-forming factors, such as climate and land use. The topsoil data set of the Land Use/Land Cover Area Frame survey (LUCAS) was used as a comprehensive database that consists of approximately 20,000 samples, each described by 12 physical and chemical parameters. After the application of TDA, results obtained were cross-checked against known grouping parameters including five types of land cover, nine types of climate and the organic carbon content of soil. Some of the grouping characteristics observed using standard approaches were confirmed by TDA (e.g., organic carbon content) but novel subtle relationships (e.g., magnitude of anthropogenic effect in soil formation), were discovered as well. The importance of this finding is that TDA is a unique mathematical technique capable of extracting complex relations hidden in soil science data sets, giving the opportunity to see the influence of physicochemical, biotic and abiotic factors on topsoil formation through fresh eyes. Copyright © 2017 Elsevier B.V. All rights reserved.

Is the Taklimakan Desert Highway Shelterbelt Sustainable to Long-Term Drip Irrigation with High Saline Groundwater?

PubMed Central

Zhang, Jianguo; Xu, Xinwen; Li, Shengyu; Zhao, Ying; Zhang, Afeng; Zhang, Tibin; Jiang, Rui

2016-01-01

Freshwater resources are scarce in desert regions. Highly saline groundwater of different salinity is being used to drip irrigate the Taklimakan Desert Highway Shelterbelt with a double-branch-pipe system controlling the irrigation cycles. In this study, to evaluate the dynamics of soil moisture and salinity under the current irrigation system, soil samples were collected to a 2-m depth in the shelterbelt planted for different years and irrigated with different groundwater salinities, and soil moisture and salinity were analyzed. The results showed that both depletion of soil moisture and increase of topsoil salinity occurred simultaneously during one irrigation cycle. Soil moisture decreased from 27.4% to 2.4% for a 15-day irrigation cycle and from 26.4% to 2.7% for a 10-day-cycle, respectively. Topsoil electrical conductivity (EC) increased from 0.64 to 3.32 dS/m and 0.70 to 3.99 dS/m for these two irrigation cycles. With increased shelterbelt age, profiled average soil moisture (0–200 cm) reduced from 12.8% (1-year) to 7.1% (10-year); however, soil moisture in 0–20-cm increased, while topsoil salinity decreased. In addition, irrigation salinity mainly affected soil salinity in the 0–20-cm range. We conclude that water supply with the double-branch-pipe is a feasible irrigation method for the Taklimakan Desert Highway Shelterbelt, and our findings provide a model for shelterbelt construction and sustainable management when using highly saline water for irrigation in analogous habitats. PMID:27711244

Lysimeter Study of Plant Water Uptake in a Model Forest Ecosystem on Heavy Metal Contaminated Soil

NASA Astrophysics Data System (ADS)

Menon, M.; Abbaspour, K.; Schulin, R.; Oswald, S.

2003-04-01

We have been investigating the impact of heavy metal stress on the water regime of young forest ecosystems grown in 32 open top lysimeters (3 m in diameter and 1 m deep). The factorial treatments of the lysimeters include variations of rainwater acidity (acidic, ambient rain), subsoil type (acidic, calcareous), and soil contamination (with and without copper, zinc and cadmium in the top 20 cm). Each lysimeter was planted in spring of 2000 with the same selection of trees and herbaceous plants. All lysimeters are equipped with tensiometers for monitoring of pressure head and time domain reflectometry for measuring of water content. Irrigation was applied equally to all lysimeters through sprinkler devices. Drainage water was collected by means of canisters installed at the bottom of the lysimeters, and thus evapotranspiration could be calculated through water balancing. We monitored the water regime for two years including an imposed drought period. Significantly more water was extracted from the calcareous than the acidic subsoil. The water potential measurements show that also the heavy metal polluted topsoil had a significant influence on the water regime. Metal stress was particularly evident under reduced irrigation. We suspect that the roots were damaged in the contaminated topsoil. In contrast to the subsoil type, heavy metal pollution did not produce a significant effect on evapotranspiration (ET) though, and neither did acidic rain. Pot experiments confirmed that in presence of clean subsoil plants compensated for metal stress in contaminated topsoil by shifting their root activity from contaminated to uncontaminated zones.

Assessment of Heavy Metal Pollution in Topsoil around Beijing Metropolis

PubMed Central

Sun, Ranhao; Chen, Liding

2016-01-01

The topsoil around Beijing metropolis, China, is experiencing impacts of rapid urbanization, intensive farming, and extensive industrial emissions. We analyzed the concentrations of Cu, Ni, Pb, Zn, Cd, and Cr from 87 topsoil samples in the pre-rainy season and 115 samples in the post-rainy season. These samples were attributed to nine land use types: forest, grass, shrub, orchard, wheat, cotton, spring maize, summer maize, and mixed farmland. The pollution index (PI) of heavy metals was calculated from the measured and background concentrations. The ecological risk index (RI) was assessed based on the PI values and toxic-response parameters. The results showed that the mean PI values of Pb, Cr, and Cd were > 1 while those of Cu, Ni, and Zn were < 1. All the samples had low ecological risk for Cu, Ni, Pb, Zn, and Cr while only 15.35% of samples had low ecological risk for Cd. Atmospheric transport rather than land use factors best explained the seasonal variations in heavy metal concentrations and the impact of atmospheric transport on heavy metal concentrations varied according to the heavy metal types. The concentrations of Cu, Cd, and Cr decreased from the pre- to post-rainy season, while those of Ni, Pb, and Zn increased during this period. Future research should be focused on the underlying atmospheric processes that lead to these spatial and seasonal variations in heavy metals. The policymaking on environmental management should pay close attention to potential ecological risks of Cd as well as identifying the transport pathways of different heavy metals. PMID:27159454

[Study on mechanism of SOM stabilization of paddy soils under long-term fertilizations].

PubMed

Luo, Lu; Zhou, Ping; Tong, Cheng-Li; Shi, Hui; Wu, Jin-Shui; Huang, Tie-Ping

2013-02-01

Fourier transform infrared spectroscopy (FTIR) was applied to study the structure of soil organic matter (SOM) of paddy soils under long-term different fertilization treatments. The aim was to clarify the different distribution of SOM between different fertilization methods and between topsoil and subsoil, and to explore the stability mechanism of SOM under different fertilization treatments. The results showed that the content of topsoil organic carbon (SOC) was the highest under organic-inorganic fertilizations, with the increment of SOC by 18.5%, 12.9% and 18.4% under high organic manure (HOM), low organic manure (LOM) and straw returning (STW) respectively compared with no fertilization treatment (CK). The long-term fertilizations also changed the chemical structure of SOM. As compared with CK, different fertilization treatments increased the functional group absorbing intensity of chemical resistance compounds (aliphatic, aromaticity), carbohydrate and organo-silicon compounds, which was the most distinctive under treatments of HOM, LOM and STW. For example, the absorbing intensity of alkyl was 0.30, 0.25 and 0.29 under HOM, LOM and STW, respectively. These values were increased by 87% , 56% and 81% as compared with that under CK treatment. The functional group absorbing intensity of SOM in the topsoil was stronger than that in the subsoil, with the most distinctive difference under HOM, LOM and STW treatments. The present research indicated that the enhanced chemical resistance of functional group of SOM may contribute to the high contents of SOC in the paddy soils under long-term organic-inorganic fertilizations, which also suggested a chemical stabilization mechanism of SOM in the paddy soils.

Factors affecting trace element content in periurban market garden subsoil in Yunnan Province, China.

PubMed

Zu, Yanqun; Bock, Laurent; Schvartz, Christian; Colinet, Gilles; Li, Yuan

2011-01-01

Field investigations were conducted to measure subsoil trace element content and factors influencing content in an intensive periurban market garden in Chenggong County, Yunnan Province, South-West China. The area was divided into three different geomorphological units: specifically, mountain (M), transition (T) and lacustrine (L). Mean trace element content in subsoil were determined for Pb (58.2 mg/kg), Cd (0.89 mg/kg), Cu (129.2 mg/kg), and Zn (97.0 mg/kg). Strong significant relationships between trace element content in topsoil and subsoil were observed. Both Pb and Zn were accumulated in topsoil (RTS (ratio of mean trace element in topsoil to subsoil) of Pb and Zn > or =1.0) and Cd and Cu in subsoil (RTS of Cd and Cu < or = 1.0). Subsoil trace element content was related to relief, stoniness, soil color, clay content, and cation exchange capacity. Except for 7.5 YR (yellow-red) color, trace element content increased with color intensity from brown to reddish brown. Significant positive relationships were observed between Fe content and that of Pb and Cu. Trace element content in mountain unit subsoil was higher than in transition and lacustrine units (M > T > L), except for Cu (T > M > L). Mean trace element content in calcareous subsoil was higher than in sandstone and shale. Mean trace element content in clay texture subsoil was higher than in sandy and sandy loam subsoil, and higher Cu and Zn content in subsoil with few mottles. It is possible to model Pb, Cd, Cu, and Zn distribution in subsoil physico-chemical characteristics to help improve agricultural practice.

Heavy metal leaching from mine tailings as affected by plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhu, D.; Schwab, A.P.; Banks, M.K.

A column experiment was conducted to determine the impact of soil cover and plants on heavy metal leaching from mine tailings and heavy metal contaminated soil. Columns made of PVC were constructed with 30 cm subsoil covered by 30 cm of mine tailings followed by 0, 30, or 60 cm subsoil covered by 30 cm of mine tailings followed by 0, 30, or 60 cm of clean topsoil. Two grasses, tall fescue (Festuca arundinacea Schreb.) and big bluestem (Andropogon gerardii), were grown in the columns. The columns were leached at a slow rate for 1 yr with a 0.001 Mmore » CaCl{sub 2} solution under unsaturated conditions. The presence of both tall fescue and big bluestem increased Zn and Cd concentrations in the leachate. Lead concentrations in leachates were not affected by the presence of plants. Although plants generally reduced the total amount of water leached, total mass of Zn and Cd leached generally was not impacted by plants. Total mass of Pb leached was positively correlated with total leachate collected from each column. Covering the mine tailings with 60 cm of topsoil increased the mass of Zn and Cd leached relative to no topsoil. When the subsoil was absent, Zn and Cd leaching increased by as much as 20-fold, verifying the ability of soil to act as a sink for metals. Mine tailing remediation by establishing vegetation can reduce Pb movement but may enhance short-term Cd and Zn leaching. However, the changes were relatively small and do not outweigh the benefits of using vegetation in mine tailings reclamation.« less

Effects of prescribed fire for pasture management on soil organic matter and biological properties: A 1-year study case in the Central Pyrenees.

PubMed

Girona-García, Antonio; Badía-Villas, David; Martí-Dalmau, Clara; Ortiz-Perpiñá, Oriol; Mora, Juan Luis; Armas-Herrera, Cecilia M

2018-03-15

Prescribed burning has been readopted in the last decade in the Central Pyrenees to stop the regression of subalpine grasslands in favour of shrublands, dominated among others by Echinospartum horridum (Vahl) Rothm. Nevertheless, the effect of this practice on soil properties is uncertain. The aim of this work was to analyse the effects of these burnings on topsoil organic matter and biological properties. Soil sampling was carried out in an autumnal prescribed fire in Buisán (NE-Spain, November 2015). Topsoil was sampled at 0-1cm, 1-2cm and 2-3cm depth in triplicate just before (U), ~1h (B0), 6months (B6) and 12months (B12) after burning. We analysed soil total organic C (TOC), total nitrogen (TN), microbial biomass C (C mic ), soil respiration (SR) and β-D-glucosidase activity. A maximum temperature of 438°C was recorded at soil surface while at 1cm depth only 31°C were reached. Burning significantly decreased TOC (-52%), TN (-44%), C mic (-57%), SR (-72%) and β-D-glucosidase (-66%) at 0-1cm depth while SR was also reduced (-45%) at 1-2cm depth. In B6 and B12, no significant changes in these properties were observed as compared to B0. It can be concluded that the impact of prescribed burning has been significant and sustained over time, although limited to the first two topsoil centimetres. Copyright © 2017 Elsevier B.V. All rights reserved.

Slumping in the rain - winter soil structure across Scotland and its physical degradation from extreme weather

NASA Astrophysics Data System (ADS)

Hall, Rebecca; Hallett, Paul; Raffan, Annette; Lilly, Allan; Baggaley, Nikki; Rowan, John; Crookes, Bill; Ball, Bruce

2017-04-01

Scotland is blessed with fertile and resilient soils that produce great cereal yields and whisky. However, there is worrying anecdotal evidence, confirmed by a small body of science, that some farming practices are causing widespread physical degradation of these soils. Studies from other UK regions have identified soil physical degradation by compaction, unstable seedbeds and erosion as a moderate to serious problem, depending on farming practice, soil properties and climate. In 2015/2016 we sampled 120 fields from 4 catchments in Scotland to describe the state of soil structure in the winter. To obtain a rapid assessment, we used the increasingly popular and easily interpretable Visual Evaluations of Soil Structure (VESS) and Subsoil Structure (SubVESS). We found severe soil structural degradation in 18% of topsoils and 9% of subsoils for 120 fields in 4 catchments. The severe 2015/2016 winter precipitation, the worst ever recorded, caused a 30% increase in occurrence of severely degraded topsoils, as determined from sampling some of the same fields before and after this unprecedented weather event. Run-off, erosion and nutrient losses were about 10X from degraded parts of fields such as tramlines than either within the field or at less trafficked boundaries. There was some agreement between areas identified as structurally degraded and those ranked as being susceptible to topsoil compaction using a simple model. Broad scale surveys that incorporate temporal sampling, such as the study reported here, are essential to provide regional assessments of soil degradation and to inform follow-on, targeted studies, where more in-depth analysis would be feasible.

Effects of borrow site preparation and fertilization on natural revegetation

DOT National Transportation Integrated Search

1987-01-01

This study report describes the effects of experimental fertilization and surface conditioning of a gravel borrow site which lacked a topsoil covering. In summary, borrow site revegetation by fireweed may be greatly enhanced by scarifying and fertili...

Use of soil stabilizers on highway shoulders.

DOT National Transportation Integrated Search

2005-01-01

This study evaluated soil additives as stabilizers for aggregate and topsoil shoulders. Its purpose was to determine (1) the effect soil stabilizers have on the strength and stability of soil shoulders, and (2) the costs and benefits of using stabili...

Relevant magnetic and soil parameters as potential indicators of soil conservation status of Mediterranean agroecosystems

NASA Astrophysics Data System (ADS)

Quijano, Laura; Chaparro, Marcos A. E.; Marié, Débora C.; Gaspar, Leticia; Navas, Ana

2014-09-01

The main sources of magnetic minerals in soils unaffected by anthropogenic pollution are iron oxides and hydroxides derived from parent materials through soil formation processes. Soil magnetic minerals can be used as indicators of environmental factors including soil forming processes, degree of pedogenesis, weathering processes and biological activities. In this study measurements of magnetic susceptibility are used to detect the presence and the concentration of soil magnetic minerals in topsoil and bulk samples in a small cultivated field, which forms a hydrological unit that can be considered to be representative of the rainfed agroecosystems of Mediterranean mountain environments. Additional magnetic studies such as isothermal remanent magnetization (IRM), anhysteretic remanent magnetization (ARM) and thermomagnetic measurements are used to identify and characterize the magnetic mineralogy of soil minerals. The objectives were to analyse the spatial variability of the magnetic parameters to assess whether topographic factors, soil redistribution processes, and soil properties such as soil texture, organic matter and carbonate contents analysed in this study, are related to the spatial distribution pattern of magnetic properties. The medians of mass specific magnetic susceptibility at low frequency (χlf) were 36.0 and 31.1 × 10-8 m3 kg-1 in bulk and topsoil samples respectively. High correlation coefficients were found between the χlf in topsoil and bulk core samples (r = 0.951, p < 0.01). In addition, volumetric magnetic susceptibility was measured in situ in the field (κis) and values varied from 13.3 to 64.0 × 10-5 SI. High correlation coefficients were found between χlf in topsoil measured in the laboratory and volumetric magnetic susceptibility field measurements (r = 0.894, p < 0.01). The results obtained from magnetic studies such as IRM, ARM and thermomagnetic measurements show the presence of magnetite, which is the predominant magnetic carrier, and hematite. The predominance of superparamagnetic minerals in upper soil layers suggests enrichment in pedogenic minerals. The finer soil particles, the organic matter content and the magnetic susceptibility values are statistically correlated and their spatial variability is related to similar physical processes. Runoff redistributes soil components including magnetic minerals and exports fine particles out the field. This research contributed to further knowledge on the application of soil magnetic properties to derive useful information on soil processes in Mediterranean cultivated soils.

Soil structure, microbial biomass and carbon and nitrogen stocks as influenced by conventional tillage and conservation techniques

NASA Astrophysics Data System (ADS)

Abrougui, Khaoula; Khemis, Chiheb; Cornelis, Wim; Chehaibi, Sayed

2017-04-01

To evaluate the impact of tillage systems on soil environment, it is necessary to quantify the modifications to physical, chemical and biological properties. The objective of this study was to evaluate the short-term impact of different tillage systems in organic farming on soil resistance to penetration, bulk density, microbial biomass, organic matter, and carbon and nitrogen stocks. The tillage systems included conventional tillage (CT), 'agronomic' tillage (AT) and superficial (shallow) tillage (ST), with ST being a non-inversion practice. Tests were carried out on alluvial poorly developed soil (10% clay, 57% silt, 33% sand) in the Higher Institute of Agronomy of Chott Meriem (Tunisia). The soil resistance to penetration was measured with a penetrologger till 50 cm depth along with soil water content measurements. Bulk density (g cm-3) was measured by a cylinder densimeter on samples collected every 10 cm till 30 cm depth. Microbial biomass is a determining factor in soil biological quality because of its role in the regulation, transformation and storage of nutrients. To count the germs, we used the method of enumeration after incorporation into agar. The Walkley and Black method was used for the determination of soil organic matter, and Kjeldahl's for the analysis of total nitrogen content. Carbon and nitrogen stocks (t ha-1) were then calculated as a function of carbon and nitrogen contents, bulk density and the horizon depth. Shallow tillage without inversion ST showed the best values in terms of soil resistance and bulk density. Indeed, soil resistance was 3.1, 2.4 and 2 MPa under CT, AT and ST respectively at 40 cm depth. By adopting this conservation technique, we noted an increase in organic matter with 53% as compared to CT (from 1.9% to 2.9%) and thus a significant increase in C (from 12.5 to 14.5 g kg-1) and N (from 5 to 8 g kg-1) stocks, particularly in the topsoil. In fact, the increase of organic matter in the topsoil constituted a reserve of essential nutrients which allowed the development and boosted the activity of living beings from 756 to 780 UFC g-1 x 105 in the topsoil as compared to CT. The overall increase of C stocks in the topsoil for ST significantly contributes to carbon sequestration.

Mineralogical effects of an experimental forest fire on a goethite/ferrihydrite soil - an attempt to solve the presence of hematite and maghemite in topsoils in a temperate region

NASA Astrophysics Data System (ADS)

Nørnberg, Per; Vendelboe, Anders L.; Gunnlaugsson, Haraldur P.; Merrison, Jonathan P.; Finster, Kai; Jensen, Svend K.

2010-05-01

Isolated soil spots, a few square metres in size, as red as Munsell colour 10R ¾ are found in Denmark. These spots are well known as places that have been exposed to fire. However, a long-standing unresolved puzzle is the presence of extended areas with high iron content (8-40 %) where goethite and ferrihydrite are present in the topsoil along with hematite and maghemite. Hematite and particularly maghemite would normally not be expected to occur under the temperate humid Danish climate, but be interpreted as the result of high temperature as found in tropical areas or after forest fires. However, a body of evidence argues against these sites having been exposed to fire. In an attempt to get closer to an explanation of this iron mineralogy, an experimental forest fire was produced. The results showed a clear mineralogical zonation down to 10 cm depth. This was not observed at the natural sites, which contained a uniform mixture of goethite/ferrihydrite, hematite and maghemite down to 20 cm depth. The experimental forest fire furthermore left charcoal and ashes at the topsoil, produced high pH and decreased organic matter content, all of which is in contrast to the natural sites. Physical and chemical date as well as XRD, Mössbauer spectroscopic data and TEM micrographs from the sites will be presented. The conclusion from this work is that the mineralogy of these sites is not consistent with exposure to fire, but may rather result from long term transformation within a reducing environment, possibly involving microorganisms. References: Nørnberg, P., Vendelboe, A.L., Gunnlaugsson, H.P., Merrison, J.P., Finster, K., Jensen, S.K. 2009 Mineralogy after an experimental forest fire on Quaternary soil goethite, compared with a hematite, maghemite, goethite containing topsoil. Clay Minerals, 44, 239-247. Nørnberg, P., Gunnlaugsson, H.P., Merrison, J.P., Vendelboe, A.L. 2009: Salten Skov I: A Martian dust analogue. Planetary and Space Science, 57, 628-631. Nørnberg, P., Schwertmann, U., Stanjek, C.B., An¬dersen, T., Gunnlaugsson, H.P. 2004: Mineralogy of Quaternary iron oxide rich formations in Denmark.Clay Minerals, 39, 85-98.

Time course of soil carbon storage, 15N and radiocarbon signature in top- and subsoil of a 60-years agricultural field trial - indications for compensating effects of carbon input and turnover

NASA Astrophysics Data System (ADS)

Leifeld, Jens; Conen, Franz; Oberholzer, Hans Rudolf; Jochen, Mayer

2014-05-01

Soil carbon dynamics are controlled by the delicate balance between carbon inputs and outputs which both are co-regulated by land use and management (LUM) as important anthropogenic drivers. Upon land use change to cropland carbon stocks generally tend to decline but often the contribution of two opposing factors, namely changes in input and decomposition rates, to soil carbon stock changes is indistinguishable. Here we report on an ongoing cropland experiment in Zurich, Switzerland, named ZOFE (Zurich Organic Fertilization Experiment), established on former grassland in 1949. ZOFE encompasses a range of mineral and organic fertilization practices and a zero fertilizer treatment as control. The experiment has a block design with five replicates per treatment. We make use of productivity and fertilization gradients in selected treatments of the ZOFE trial to evaluate how low or high inputs (induced by differential yields and organic fertilization) may affect soil organic carbon storage and transformation. For the most recent sampling that also included subsoil down to 0.9 m, all properties were measured for every single replicate. Topsoil carbon storage declined after grassland conversion at rates of c. 0.2 t C ha-1 a-1, particularly in treatments with mineral fertilizer and high yields, and without fertilization and low yields. Organic matter amendments such as manure or compost could partially offset but not fully compensate some of the topsoil carbon loss. Over time the soil's delta 15N signature declined as well, probably due to increased atmospheric nitrogen deposition. It increased from the top- to the subsoil, indicating increasing microbial transformation, particularly with manure added. The soil's radiocarbon signature revealed distinct bomb peak patterns in all treatments but only in the topsoil. The 14C data confirmed that with higher productivity more recent organic matter was incorporated, both in top and subsoil. Because, in contrast to topsoil, subsoil carbon storage was similar among treatments, the results tentatively indicate that in the ZOFE trial higher subsoil carbon inputs, owing to high productivity and additional organic amendments, do not enhance subsoil carbon storage but higher inputs are counterbalanced by faster soil organic matter decomposition.

Connectivity of rainfall and human activity impacts on soil erosion processes in Mediterranean vineyards

NASA Astrophysics Data System (ADS)

Rodrigo-Comino, Jesús; Terol Esparza, Enric; Damián Ruiz-Sinoga, José; Cerdà, Artemi

2017-04-01

Soils are recognized as one of the most important components characterizing a terroir (Vaudour et al., 2015). However, the soils of vineyards are one of the most degraded in comparison to other cultivated context due to traditional tillage management (Prosdocimi et al., 2016). The key factor to understand the connectivity between topsoil redistribution and overland flow is the human activity as the management, who can reduce or increase these geomorphological interchanges (sediment and runoff) and changes the soil properties such it was found in different regions and under different crops (Parras-Alcántara et al., 2016). In order to assess this topsoil redistribution in vineyards, the Stock Unearthing Method (SUM) has been accepted to be a reliable method to assess erosion rates and spatial evolution and interchanging of the topsoil, sediments and water flux directions at long-term time scales in vineyards (Brenot et al., 2008; Paroissien et al., 2010; Rodrigo Comino et al., 2016). The SUM is based on the measurement of the distance from the topsoil to the grafted vine stock, confirmed as a passive indicator of topsoil movements since the initial planting of vine stocks. Therefore, the aims of this work are: i) to quantify the soil erosion rates by means of Stock Unearthing Method; ii) to measure the impact of plantation of new vineyards; iii) to compare sediment transport, water flux directions and topsoil redistributions between different soil types, land management (bare soil, amendments, straw mulch…) and soil tillage practices; iv) to assess sediment budgets and water flux direction conditioned by the micro-topographical variations; and, v) to detect key factors and impact on the surface features within the detected connectivity processes (rills and inter-rills…) using cartography. Acknowledgements The research leading to these results has received funding from the COST Action (Connecting European Connectivity Research): ES1306 and the European Union Seventh Framework Programme (FP7/2007-2013) under grant no. 603498 (RECARE Project). References Brenot, J., Quiquerez, A., Petit, C., Garcia, J.-P., 2008. Erosion rates and sediment budgets in vineyards at 1-m resolution based on stock unearthing (Burgundy, France). Geomorphology 100, 345-355. doi:10.1016/j.geomorph.2008.01.005 López-Vicente, M., Nadal-Romero, E., Cammeraat, E.L.H., 2016. Hydrological Connectivity Does Change Over 70 Years of Abandonment and Afforestation in the Spanish Pyrenees. Land Degrad. Dev. n/a-n/a. doi:10.1002/ldr.2531 Paroissien, J.-B., Lagacherie, P., Le Bissonnais, Y., 2010. A regional-scale study of multi-decennial erosion of vineyard fields using vine-stock unearthing-burying measurements. Catena 82, 159-168. doi:10.1016/j.catena.2010.06.002 Parras-Alcántara, L., Lozano-García, B., Keesstra, S., Cerdà, A., Brevik, E.C., 2016. Long-term effects of soil management on ecosystem services and soil loss estimation in olive grove top soils. Sci. Total Environ. 571, 498-506. doi:10.1016/j.scitotenv.2016.07.016 Prosdocimi, M., Cerdà, A., Tarolli, P., 2016. Soil water erosion on Mediterranean vineyards: A review. Catena 141, 1-21. doi:10.1016/j.catena.2016.02.010 Rodrigo Comino, J., Quiquerez, A., Follain, S., Raclot, D., Le Bissonnais, Y., Casalí, J., Giménez, R., Cerdà, A., Keesstra, S.D., Brevik, E.C., Pereira, P., Senciales, J.M., Seeger, M., Ruiz Sinoga, J.D., Ries, J.B., 2016. Soil erosion in sloping vineyards assessed by using botanical indicators and sediment collectors in the Ruwer-Mosel valley. Agric. Ecosyst. Environ. 233, 158-170. doi:10.1016/j.agee.2016.09.009 Vaudour, E., Costantini, E., Jones, G.V., Mocali, S., 2015. An overview of the recent approaches to terroir functional modelling, footprinting and zoning. SOIL 1, 287-312. doi:10.5194/soil-1-287-2015

Soil amendments improve microbial ecology parameters of "topsoil inoculum" used in post-mining restoration

NASA Astrophysics Data System (ADS)

Kumaresan, Deepak; Munoz-Rojas, Miriam; Moreira-Grez, Benjamin; Kariman, Khalil; Whiteley, Andrew

2017-04-01

Mine operations generate substantial volumes of waste substrates, which are crushed and/or chemically treated waste rock from which ores are extracted. Establishment of rehabilitated landforms using post-mining substrates (i.e. waste rocks, tailings) that typically exhibit extreme conditions (such as high pH, nutrient deficiency, excessive salinity and metal toxicity) can be a major environmental problem and a critical issue during mine closure operations. More importantly, mine sites are located predominantly in arid or semi-arid lands where our understanding of basic ecosystem processes and microbial interactions with native plants (e.g. Eucalyptus spp., Acacia spp., Grevillea spp. in Western Australia) are limited. Despite the wide acknowledgement on the impact of microbial functional diversity on overall soil and plant health, no detailed attention has been paid to understand the role of belowground microbial functional diversity in the context of mine rehabilitation strategies. In this research, we investigated the role of nitrogen-based and microbial consortia amendments on improving the microbial ecology parameters of "topsoil inoculum" and subsequently its cascading effect on seedling establishment and plant morphology of Acacia ancistrocarpa, a legume native to the Pilbara and other regions of Western Australia and commonly used in arid zone restoration. The study was conducted under controlled environmental conditions in potted plants using topsoil retrieved from previously stockpiled material as growth media. A morphological assessment was undertaken to measure shoot length, shoot weight, root length, root area and root weight. Soil chemical properties, e.g. carbon, nitrogen and trace metals concentrations were determined Microbial activity was measured with the 1-day CO2 test, which determines soil microbial respiration rate based on the measurement of the CO2 burst produced after moistening dry soil (Muñoz-Rojas et al., 2016). Bacterial and archaeal community composition was assessed using high-throughput sequencing of the 16S rRNA marker gene analysis (Whiteley et al., 2012). Our results showed significant (P <0.05) larger rates of microbial activity and shoot:root ratio in those pots amended with both N and microbial consortia. Both amendments significantly influenced the chemical and bacterial-archaeal community composition in the topsoil inoculum. Topsoil amended with inorganic nitrogen revealed higher relative abundance of 16S rRNA gene sequences related to phylum Nitrospira, Planctomycetes, Gemmatimonadetes and Cyanobacteria/Chloroplast in comparison to "water-only" (control) and "microbial consortia" treatment. Addition of microbial consortia to topsoil significantly increased the concentrations of soil potassium, iron, copper and manganese. Interestingly, a large proportion of sequences that can only be assigned at the domain level (either Bacteria or Archaea) were detected in the control samples suggesting the presence of novel taxa/lineages in the native soil and their relative abundances are significantly influenced by the addition of amendments. Our data indicates that whilst amendments results significant improvement of plant growth and establishment at early stages it also results in considerable phylogenetic divergence within soil bacterial/archaeal communities, in particular loss of indigenous taxa/lineages that could have above-below ground feedback with native plants. Muñoz-Rojas M, Erickson TE, Martini D, Dixon KW, Merritt DJ. 2016. Soil physicochemical and microbiological indicators of short, medium and long term post-fire recovery in semi-arid ecosystems. Ecological indicators 63, 14-22.DOI: 10.1016/j.ecolind.2015.11.038 Whiteley AS, Jenkins S, Waite I, Kresoje N, Payne H, Mullan B, Allcock R, O'Donnell AG. Microbial 16S rRNA Ion Tag and community metagenome sequencing using the Ion Torrent (PGM) Platform. J Microbiol Methods 91, 80-88, doi:10.1016/j.mimet.2012.07.008 (2012).

Green Infrastructure and Watershed-Scale Hydrology in Mixed Land Cover System

EPA Science Inventory

Urbanization results in replacement of pervious areas (e.g., vegetation, topsoil) with impervious surfaces such as roads, roofs, and parking lots, which cause reductions in interception, evapotranspiration, and infiltration, and increases in surface runoff (overland flow) and pol...

Spatial Characterization of Riparian Buffer Effects on Sediment Loads from Watershed Systems

EPA Science Inventory

Understanding all watershed systems and their interactions is a complex, but critical, undertaking when developing practices designed to reduce topsoil loss and chemical/nutrient transport from agricultural fields. The presence of riparian buffer vegetation in agricultural lands...

Immediate changes in topsoil chemical properties after controlled shrubland burning in the Central Pyrenees

NASA Astrophysics Data System (ADS)

Zufiaurre-Galarza, Raquel; Fernández Campos, Marta; Badía-Villas, David; María Armas-Herrera, Cecilia; Martí-Dalmau, Clara; Girona-García, Antonio

2016-04-01

Prescribed fire has recently been adopted as an encroachment-fighting strategy in the Central Pyrenees. Despite relatively large information on wildfire impacts on soil, there is little information on prescribed fire effects, especially in mountain ecosystems (Shakesby et al, 2015). Fire effects are noticeable in the topsoil, particularly in relation to soil organic matter and nutrient contents and quality (Alexis et al, 2012). These components change with time after fire and at the scale of the upper few centimetres of mineral soil (Badía et al, 2014). The aim of this study is to evaluate the immediate effects of prescribed shrubland burning on soil's nutrients and organic matter content to detect changes at cm-scale, trying to differentiate the heat shock from the subsequent incorporation of ash and charcoal. The study area, densely covered with spiny broom (Echinospartum horridum), is located in Tella (Central Pyrenees, NE Spain) at 1900 meters above sea level. Three sites were sampled before burning and immediately after burning just in its adjacent side. The soils belong to the WRB unit Leptic Eutric Cambisol, Soil samples were collected separating carefully the organic layers (litter in unburned soils and ashes and fire-altered organic residues in burned soils) and the mineral horizon at 0-1, 1-2 and 2-3 cm depths. Soil samples were air-dried and sieved to 2 mm. Soil organic C (by the wet oxidation method), total N (Kjeldahl method), water-soluble ions (Ca2+, Mg2+, Na+, K+, SO4=, NO3- and NH4+), exchangeable ions (Ca2+, Mg2+, K+, Na+, Fe3+ and Mn2+), total and available P, pH (1:5) and the electrical conductivity (in a 1:10 soil-to-water ratio) were measured. Immediately after the controlled fire, soil organic carbon content on burned topsoil decreases significantly within 0-3 cm of soil depth studied while total N decrease was not significant. Moreover, only a slight increase of the electrical conductivity, water-soluble ions and exchangeable ions was observed on burned topsoil. These changes detected immediately after fire (SOC decrease and slight nutrients increase) are related to the heat released during the severe intensity of prescribed burning. Few changes in nutrients are yet observed due to the negligible incorporation of ashes into the soil, still remaining on the surface. In the medium term, it can be expected its partial incorporation into the soil and, also, ash and soil losses depending on the rain intensity and the amount of time in which the soil is kept bare. REFERENCES Alexis et al. (2012). Evolution of soil organic matter after prescribed fire: A 20-year chronosequence. Geoderma 189-190: 98-107. Badía et al. (2014). Wildfire effects on nutrients and organic carbon of a Rendzic Phaeozem in NE Spain: Changes at cm-scale topsoil. Catena 113: 267-275. Shakesby et al. (2015). Impacts of prescribed fire on soil loss and soil quality: An assessment based on an experimentally-burned catchment in central Portugal. Catena 128: 278-293

Losing Ground

ERIC Educational Resources Information Center

Eckholm, Erik

1976-01-01

Past unsound agricultural practices coupled with drought and high winds eroded away topsoil in the Great Plains. Because of technology and food surpluses productivity returned to the deteriorated lands. Ecosystem overstress could become devastating especially in poor countries as food surpluses and energy decline and populations soar. (MR)

Performance-based specifications for temporary erosion and sediment control during construction : a survey of state practice.

DOT National Transportation Integrated Search

2013-03-01

During construction projects, surrounding soils can be disrupted, causing ecological damage through topsoil erosion and pollution of waterways with sediment. MnDOT currently has requirements and inspection procedures to ensure that contractors take m...

Initial growth of leguminous trees and shrubs in a cut gold mined area in Minas Gerais State, Brazil

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dias, L.E.; Campello, E.F.C.; Ribeiro, E.S. Jr.

In an opencast gold mining in Minas Gerais State, Brazil, leguminous trees and shrubs were used to revegetate an acid cut mined area. the substrate was high in pyrite content (3%) and received 50 cm of covered material in two layers: (1) insulating layer of 20 cm where clay or a mining refuse (MR) was used to prevent the pyrite oxidation, and (2) an upper layer with 30 cm formed by topsoil or topsoil + urban compost (3:1 v/v). After the application of the cover materials, planting holes were manually made spaced by 1 x 1 m. Each hole receivedmore » limestone (100 g), rock phosphate (150 g), potassium chloride (45 g) and cattle manure (2 L). Fifteen leguminous species were planted an each plot (15 x 8 m), spaced by 1.0 x 1.0 m (one specie per row). Sixteen months after the planting the plants were evaluated and the results showed an effect of substrate on the plants survival, height, and diameter. The use of clay as insulating layer was better than mining refuse and the plants did not respond to the addition of urban compost to the topsoil. Among the evaluated species, Thephrosia sinapau, Erytrina verna, Dipterix alata and Stryphnodenadrum guyanensis showed a mortality rate of 100% after 16 months while Sesbania marginata, Acacaia holosericea, Mimosa pellita, Acacia crassicarpa, Acacia mangium and Acacia angustissima exhibited more adaptation capacity to the acid substrate. Analyses from the substrate showed higher exchangeable acidity (Al{sup 3+}) for the plots receiving MR as insulating layer. This study has applications for the acid mine drainage from coal mines of Brazil.« less

Predictive Mapping of Topsoil Organic Carbon in an Alpine Environment Aided by Landsat TM

PubMed Central

Yang, Renmin; Rossiter, David G.; Liu, Feng; Lu, Yuanyuan; Yang, Fan; Yang, Fei; Zhao, Yuguo; Li, Decheng; Zhang, Ganlin

2015-01-01

The objective of this study was to examine the reflectance of Landsat TM imagery for mapping soil organic Carbon (SOC) content in an Alpine environment. The studied area (ca. 3*104 km2) is the upper reaches of the Heihe River at the northeast edge of the Tibetan plateau, China. A set (105) of topsoil samples were analyzed for SOC. Boosted regression tree (BRT) models using Landsat TM imagery were built to predict SOC content, alone or with topography and climate covariates (temperature and precipitation). The best model, combining all covariates, was only marginally better than using only imagery. Imagery alone was sufficient to build a reasonable model; this was a bit better than only using topography and climate covariates. The Lin’s concordance correlation coefficient values of the imagery only model and the full model are very close, larger than the topography and climate variables based model. In the full model, SOC was mainly explained by Landsat TM imagery (65% relative importance), followed by climate variables (20%) and topography (15% of relative importance). The good results from imagery are likely due to (1) the strong dependence of SOC on native vegetation intensity in this Alpine environment; (2) the strong correlation in this environment between imagery and environmental covariables, especially elevation (corresponding to temperature), precipitation, and slope aspect. We conclude that multispectral satellite data from Landsat TM images may be used to predict topsoil SOC with reasonable accuracy in Alpine regions, and perhaps other regions covered with natural vegetation, and that adding topography and climate covariables to the satellite data can improve the predictive accuracy. PMID:26473739

Environmental drivers of spatial patterns of topsoil nitrogen and phosphorus under monsoon conditions in a complex terrain of South Korea

PubMed Central

Choi, Kwanghun; Spohn, Marie; Park, Soo Jin; Huwe, Bernd; Ließ, Mareike

2017-01-01

Nitrogen (N) and phosphorus (P) in topsoils are critical for plant nutrition. Relatively little is known about the spatial patterns of N and P in the organic layer of mountainous landscapes. Therefore, the spatial distributions of N and P in both the organic layer and the A horizon were analyzed using a light detection and ranging (LiDAR) digital elevation model and vegetation metrics. The objective of the study was to analyze the effect of vegetation and topography on the spatial patterns of N and P in a small watershed covered by forest in South Korea. Soil samples were collected using the conditioned latin hypercube method. LiDAR vegetation metrics, the normalized difference vegetation index (NDVI), and terrain parameters were derived as predictors. Spatial explicit predictions of N/P ratios were obtained using a random forest with uncertainty analysis. We tested different strategies of model validation (repeated 2-fold to 20-fold and leave-one-out cross validation). Repeated 10-fold cross validation was selected for model validation due to the comparatively high accuracy and low variance of prediction. Surface curvature was the best predictor of P contents in the organic layer and in the A horizon, while LiDAR vegetation metrics and NDVI were important predictors of N in the organic layer. N/P ratios increased with surface curvature and were higher on the convex upper slope than on the concave lower slope. This was due to P enrichment of the soil on the lower slope and a more even spatial distribution of N. Our digital soil maps showed that the topsoils on the upper slopes contained relatively little P. These findings are critical for understanding N and P dynamics in mountainous ecosystems. PMID:28837590

Crop response to deep tillage - a meta-analysis

NASA Astrophysics Data System (ADS)

Schneider, Florian; Don, Axel; Hennings, Inga; Schmittmann, Oliver; Seidel, Sabine J.

2017-04-01

Subsoil, i.e. the soil layer below the topsoil, stores tremendous stocks of nutrients and can keep water even under drought conditions. Deep tillage may be a method to enhance the plant-availability of subsoil resources. However, in field trials, deep tillage effects on crop yields were inconsistent. Therefore, we conducted a meta-analysis of crop yield response to subsoiling, deep ploughing and deep mixing of soil profiles. Our search resulted in 1530 yield comparisons following deep and conventional control tillage on 67 experimental cropping sites. The vast majority of the data derived from temperate latitudes, from trials conducted in the USA (679 observations) and Germany (630 observations). On average, crop yield response to deep tillage was slightly positive (6% increase). However, individual deep tillage effects were highly scattered including about 40% yield depressions after deep tillage. Deep tillage on soils with root restrictive layers increased crop yields about 20%, while soils containing >70% silt increased the risk of yield depressions following deep tillage. Generally, deep tillage effects increased with drought intensity indicating deep tillage as climate adaptation measure at certain sites. Our results suggest that deep tillage can facilitate the plant-availability of subsoil nutrients, which increases crop yields if (i) nutrients in the topsoil are growth limiting, and (ii) deep tillage does not come at the cost of impairing topsoil fertility. On sites with root restrictive soil layers, deep tillage can be an effective measure to mitigate drought stress and improve the resilience of crops. However, deep tillage should only be performed on soils with a stable structure, i.e. <70% silt content. We will discuss the contribution of deep tillage options to enhance the sustainability of agricultural production by facilitating the uptake of nutrients and water from the subsoil.

Modelling the genesis of equatorial podzols: age and implications for carbon fluxes

NASA Astrophysics Data System (ADS)

Doupoux, Cédric; Merdy, Patricia; Régina Montes, Célia; Nunan, Naoise; José Melfi, Adolpho; José Ribeiro Pereira, Osvaldo; Lucas, Yves

2017-05-01

Amazonian podzols store huge amounts of carbon and play a key role in transferring organic matter to the Amazon River. In order to better understand their C dynamics, we modelled the formation of representative Amazonian podzol profiles by constraining both total carbon and radiocarbon. We determined the relationships between total carbon and radiocarbon in organic C pools numerically by setting constant C and 14C inputs over time. The model was an effective tool for determining the order of magnitude of the carbon fluxes and the time of genesis of the main carbon-containing horizons, i.e. the topsoil and deep Bh. We performed retrocalculations to take into account the bomb carbon in the young topsoil horizons (calculated apparent 14C age from 62 to 109 years). We modelled four profiles representative of Amazonian podzols, two profiles with an old Bh (calculated apparent 14C age 6.8 × 103 and 8.4 × 103 years) and two profiles with a very old Bh (calculated apparent 14C age 23.2 × 103 and 25.1 × 103 years). The calculated fluxes from the topsoil to the perched water table indicate that the most waterlogged zones of the podzolized areas are the main source of dissolved organic matter found in the river network. It was necessary to consider two Bh carbon pools to accurately represent the carbon fluxes leaving the Bh as observed in previous studies. We found that the genesis time of the studied soils was necessarily longer than 15 × 103 and 130 × 103 years for the two younger and two older Bhs, respectively, and that the genesis time calculated considering the more likely settings runs to around 15 × 103-25 × 103 and 150 × 103-250 × 103 years, respectively.

Increased topsoil carbon stock across China's forests.

PubMed

Yang, Yuanhe; Li, Pin; Ding, Jinzhi; Zhao, Xia; Ma, Wenhong; Ji, Chengjun; Fang, Jingyun

2014-08-01

Biomass carbon accumulation in forest ecosystems is a widespread phenomenon at both regional and global scales. However, as coupled carbon-climate models predicted, a positive feedback could be triggered if accelerated soil carbon decomposition offsets enhanced vegetation growth under a warming climate. It is thus crucial to reveal whether and how soil carbon stock in forest ecosystems has changed over recent decades. However, large-scale changes in soil carbon stock across forest ecosystems have not yet been carefully examined at both regional and global scales, which have been widely perceived as a big bottleneck in untangling carbon-climate feedback. Using newly developed database and sophisticated data mining approach, here we evaluated temporal changes in topsoil carbon stock across major forest ecosystem in China and analysed potential drivers in soil carbon dynamics over broad geographical scale. Our results indicated that topsoil carbon stock increased significantly within all of five major forest types during the period of 1980s-2000s, with an overall rate of 20.0 g C m(-2) yr(-1) (95% confidence interval, 14.1-25.5). The magnitude of soil carbon accumulation across coniferous forests and coniferous/broadleaved mixed forests exhibited meaningful increases with both mean annual temperature and precipitation. Moreover, soil carbon dynamics across these forest ecosystems were positively associated with clay content, with a larger amount of SOC accumulation occurring in fine-textured soils. In contrast, changes in soil carbon stock across broadleaved forests were insensitive to either climatic or edaphic variables. Overall, these results suggest that soil carbon accumulation does not counteract vegetation carbon sequestration across China's forest ecosystems. The combination of soil carbon accumulation and vegetation carbon sequestration triggers a negative feedback to climate warming, rather than a positive feedback predicted by coupled carbon-climate models. © 2014 John Wiley & Sons Ltd.

Carbon stock and turnover in riparian soils under lowland rainforest transformation systems on Sumatra, Indonesia

NASA Astrophysics Data System (ADS)

Hennings, Nina; Kuzyakov, Yakov

2017-04-01

In many tropical areas, rainforests are being cleared in order to exploit timber and other forest products as well as plant crops for food, feed and fuel use. The determinants of different patterns of deforestation and the roles of resulting transformation systems of tropical riparian rainforests for ecological functions have yet received little attention in scientific research. Especially C stocks in riparian zones are strongly affected by climate and land use changes that lead to changes in water regime and ground water level drops. We investigated the effects of land transformations in riparian ecosystems of Sumatra, on soil C content, stocks and decomposability at the landscape scale. We compare C losses in transformation systems and rainforests and estimate the contribution of soil erosion and organic matter mineralization. Further, these losses are related to changing water level and temperature increase along increasing distance to the stream. This approach is based on changing δ13C values of SOC in the topsoil as compared to those in subsoil. The shift of δ13C of SOC in the topsoil from the linear regression calculated by δ13C value with log(SOC) in the topsoil represents the modification of the C turnover rate in the top soil. Erosion is estimated by the shift of the δ13C value of SOC in the subsoil under plantations. Further, the δ13C and δ15N soil profiles and their comparison with litter of local vegetation, can be used to estimate the contribution of autochthonous and allochthonous organics to soil C stocks. Preliminary results show strong increase of erosive losses, increased decomposition with land-use transformation and decrease of C stocks with decreasing water table.

Effect of different soil textures on leaching potential and degradation of pesticides in biobeds.

PubMed

Fogg, Paul; Boxall, Alistair B A; Walker, Allan; Jukes, Andrew

2004-09-08

Biobeds can be used to intercept pesticide-contaminated runoff from the mixing/washdown area, creating optimum conditions for sorption and biodegradation such that the amount of pesticide reaching adjacent water bodies is significantly reduced. The biobed is built on the farm using locally available materials, which include, straw, compost, and topsoil. The topsoil acts as the inoculum for the system and is likely to vary in terms of its physical, chemical, and microbiological characteristics from one farm to another. This study therefore investigated the effects of using different soil types on the degradation and leaching potential from biobeds. Three contrasting topsoils were investigated. Leaching studies were performed using isoproturon, dimethoate, and mecoprop-P, which were applied at simulated disposal rates to 1.5 m deep biobeds. Annual average concentrations were similar for each soil type with leaching losses of even the most mobile (Koc = 12-25) pesticide <1.64% of the applied dose. Greater than 98% of the retained pesticides were degraded in all matrices. Degradation studies investigated the persistence of individual pesticides and pesticide mixtures in the different matrices. DT50 values for isoproturon, chlorothalonil, mecoprop-P, and metsulfuron-methyl applied at 4 times the maximum approved rate were similar across the biomix types and were all less than or equal to reported DT50 values for soil treated at approved rates. When applied as a mixture, DT50 values in each biomix increased, indicating that interactions between pesticides are possible. However, DT90 values of <167 days were obtained in all circumstances, indicating a negligible risk of accumulation. Studies therefore indicate that substrate will have little impact on biobed performance so it should be possible to use local soils in the construction process.

Relationships between magnetic susceptibility and heavy metals in urban topsoils in the arid region of Isfahan, central Iran

NASA Astrophysics Data System (ADS)

Karimi, Rezvan; Ayoubi, Shamsollah; Jalalian, Ahmad; Sheikh-Hosseini, Ahmad Reza; Afyuni, Majid

2011-05-01

Recently methods dealing with magnetometry have been proposed as a proper proxy for assessing the heavy metal pollution of soils. A total of 113 topsoil samples were collected from public parks and green strips along the rim of roads with high-density traffic within the city of Isfahan, central Iran. The magnetic susceptibility (χ) of the collected soil samples was measured at both low and high frequency (χlf and χhf) using the Bartington MS2 dual frequency sensor. As, Cd, Cr, Ba, Cu, Mn, Pb, Zn, Sr and V concentrations were measured in the all collected soil samples. Significant correlations were found between Zn and Cu (0.85) and between Zn and Pb (0.84). The χfd value of urban topsoil varied from 0.45% to 7.7%. Low mean value of χfd indicated that the magnetic properties of the samples are predominately contributed by multi-domain grains, rather than by super-paramagnetic particles. Lead, Cu, Zn, and Ba showed positive significant correlations with magnetic susceptibility, but As, Sr, Cd, Mn, Cr and V, had no significant correlation with the magnetic susceptibility. There was a significant correlation between pollution load index (PLI) and χlf. PLI was computed to evaluate the soil environmental quality of selected heavy metals. Moreover, the results of multiple regression analysis between χlf and heavy metal concentrations indicated the LnPb, V and LnCu could explain approximately 54% of the total variability of χlf in the study area. These results indicate the potential of the magnetometric methods to evaluate the heavy metal pollution of soils.

Thin soil layer of green roof systems studied by X-Ray CT

NASA Astrophysics Data System (ADS)

Šácha, Jan; Jelínková, Vladimíra; Dohnal, Michal

2016-04-01

The popular non-invasive visualization technique of X-ray computed tomography (CT) has been used for 3D examination of thin soil layer of vegetated roof systems. The two categories of anthropogenic soils, usually used for green roof systems, were scanned during the first months after green roof system construction. First was represented by stripped topsoil with admixed crushed bricks and was well graded in terms of particle size distribution. The other category represented a commercial lightweight technogenic substrate. The undisturbed soil samples of total volume of 62.8 ccm were studied be means of X-ray Computed Tomography using X-ray Inspection System GE Phoenix Nanomex 180T with resulting spatial resolution about 57 μm in all directions. For both soil categories visible macroporosity, connectivity (described by the Euler characteristic), dimensionless connectivity and critical cross section of pore network were determined. Moreover, the temporal structural changes of studied soils were discussed together with heat and water regime of the green roof system. The analysis of CT images of anthropogenic soils was problematic due to the different X-ray attenuation of individual constituents. The correct determination of the threshold image intensity differentiating the soil constituents from the air phase had substantial importance for soil pore network analyses. However, X-ray CT derived macroporosity profiles reveal significant temporal changes notably in the soil comprised the stripped topsoil with admixed crushed bricks. The results implies that the technogenic substrate is structurally more stable over time compared to the stripped topsoil. The research was realized as a part of the University Centre for Energy Efficient Buildings supported by the EU and with financial support from the Czech Science Foundation under project number 14-10455P.

Seasonal growth and translocation of some major and trace elements in two Mediterranean grasses (Stipa tenacissima Loefl. ex L. and Lygeum spartum Loefl. ex L.)

NASA Astrophysics Data System (ADS)

Nedjimi, Bouzid

2018-05-01

The rangelands of Stipa tenacissima and Lygeum spartum (Poaceae) constitute one of the main typical ecosystems in the Iberian Peninsula and North Africa. This study examines the seasonal changes in aboveground biomass accumulation and translocation of some major (Ca and K) and trace elements (Br, Cr, Cu, Fe, Mn, Sr and Zn) from topsoil to shoots of these perennial grasses. Species, season and their interaction significantly affected the dry biomass (DW) and chemical composition of both species and their surrounding soil. The maximum DW was found in spring due to high physiological activity and was correlated positively with rainfall. A significant relationship between seasons and chemical elements was found. For both species the maximum concentrations of Ca, Cu and Zn were found in spring season. However L. spartum had the highest concentrations of K, Cr, Br, and Sr in autumn season, indicating exceptional ability of these species to accumulate large contents of these elements during the active growth periods. By way of contrast, in the topsoil the highest concentrations of almost all chemical elements were found in summer and autumn. Principal component analyses (PCA) showed that growth of L. spartum was highly associated with K, Ca, Zn, Br and Sr, whereas topsoil was correlated with Cu, Cr, Fe and Mn concentrations. Translocation factor (TFx) of chemical elements was not identical across the two species, demonstrating inter-specific variability to uptake chemical elements. The maximum values of TFx were recorded for K, Ca and Sr especially for L. spartum. To cope with arid conditions, S. tenacissima and L. spartum sprout quickly by increasing their rate of growth and nutrient uptake as soon as soil water is available after the rain.

Mapping the Distribution of Anthrax in Mainland China, 2005-2013.

PubMed

Chen, Wan-Jun; Lai, Sheng-Jie; Yang, Yang; Liu, Kun; Li, Xin-Lou; Yao, Hong-Wu; Li, Yu; Zhou, Hang; Wang, Li-Ping; Mu, Di; Yin, Wen-Wu; Fang, Li-Qun; Yu, Hong-Jie; Cao, Wu-Chun

2016-04-01

Anthrax, a global re-emerging zoonotic disease in recent years is enzootic in mainland China. Despite its significance to the public health, spatiotemporal distributions of the disease in human and livestock and its potential driving factors remain poorly understood. Using the national surveillance data of human and livestock anthrax from 2005 to 2013, we conducted a retrospective epidemiological study and risk assessment of anthrax in mainland China. The potential determinants for the temporal and spatial distributions of human anthrax were also explored. We found that the majority of human anthrax cases were located in six provinces in western and northeastern China, and five clustering areas with higher incidences were identified. The disease mostly peaked in July or August, and males aged 30-49 years had higher incidence than other subgroups. Monthly incidence of human anthrax was positively correlated with monthly average temperature, relative humidity and monthly accumulative rainfall with lags of 0-2 months. A boosted regression trees (BRT) model at the county level reveals that densities of cattle, sheep and human, coverage of meadow, coverage of typical grassland, elevation, coverage of topsoil with pH > 6.1, concentration of organic carbon in topsoil, and the meteorological factors have contributed substantially to the spatial distribution of the disease. The model-predicted probability of occurrence of human cases in mainland China was mapped at the county level. Anthrax in China was characterized by significant seasonality and spatial clustering. The spatial distribution of human anthrax was largely driven by livestock husbandry, human density, land cover, elevation, topsoil features and climate. Enhanced surveillance and intervention for livestock and human anthrax in the high-risk regions, particularly on the Qinghai-Tibetan Plateau, is the key to the prevention of human infections.

Mapping the Distribution of Anthrax in Mainland China, 2005–2013

PubMed Central

Yang, Yang; Liu, Kun; Li, Xin-Lou; Yao, Hong-Wu; Li, Yu; Zhou, Hang; Wang, Li-Ping; Mu, Di; Yin, Wen-Wu; Fang, Li-Qun; Yu, Hong-Jie; Cao, Wu-Chun

2016-01-01

Background Anthrax, a global re-emerging zoonotic disease in recent years is enzootic in mainland China. Despite its significance to the public health, spatiotemporal distributions of the disease in human and livestock and its potential driving factors remain poorly understood. Methodology/Principal Findings Using the national surveillance data of human and livestock anthrax from 2005 to 2013, we conducted a retrospective epidemiological study and risk assessment of anthrax in mainland China. The potential determinants for the temporal and spatial distributions of human anthrax were also explored. We found that the majority of human anthrax cases were located in six provinces in western and northeastern China, and five clustering areas with higher incidences were identified. The disease mostly peaked in July or August, and males aged 30–49 years had higher incidence than other subgroups. Monthly incidence of human anthrax was positively correlated with monthly average temperature, relative humidity and monthly accumulative rainfall with lags of 0–2 months. A boosted regression trees (BRT) model at the county level reveals that densities of cattle, sheep and human, coverage of meadow, coverage of typical grassland, elevation, coverage of topsoil with pH > 6.1, concentration of organic carbon in topsoil, and the meteorological factors have contributed substantially to the spatial distribution of the disease. The model-predicted probability of occurrence of human cases in mainland China was mapped at the county level. Conclusions/Significance Anthrax in China was characterized by significant seasonality and spatial clustering. The spatial distribution of human anthrax was largely driven by livestock husbandry, human density, land cover, elevation, topsoil features and climate. Enhanced surveillance and intervention for livestock and human anthrax in the high-risk regions, particularly on the Qinghai-Tibetan Plateau, is the key to the prevention of human infections. PMID:27097318

Comparison of spatial association approaches for landscape mapping of soil organic carbon stocks

NASA Astrophysics Data System (ADS)

Miller, B. A.; Koszinski, S.; Wehrhan, M.; Sommer, M.

2015-03-01

The distribution of soil organic carbon (SOC) can be variable at small analysis scales, but consideration of its role in regional and global issues demands the mapping of large extents. There are many different strategies for mapping SOC, among which is to model the variables needed to calculate the SOC stock indirectly or to model the SOC stock directly. The purpose of this research is to compare direct and indirect approaches to mapping SOC stocks from rule-based, multiple linear regression models applied at the landscape scale via spatial association. The final products for both strategies are high-resolution maps of SOC stocks (kg m-2), covering an area of 122 km2, with accompanying maps of estimated error. For the direct modelling approach, the estimated error map was based on the internal error estimations from the model rules. For the indirect approach, the estimated error map was produced by spatially combining the error estimates of component models via standard error propagation equations. We compared these two strategies for mapping SOC stocks on the basis of the qualities of the resulting maps as well as the magnitude and distribution of the estimated error. The direct approach produced a map with less spatial variation than the map produced by the indirect approach. The increased spatial variation represented by the indirect approach improved R2 values for the topsoil and subsoil stocks. Although the indirect approach had a lower mean estimated error for the topsoil stock, the mean estimated error for the total SOC stock (topsoil + subsoil) was lower for the direct approach. For these reasons, we recommend the direct approach to modelling SOC stocks be considered a more conservative estimate of the SOC stocks' spatial distribution.

Comparison of spatial association approaches for landscape mapping of soil organic carbon stocks

NASA Astrophysics Data System (ADS)

Miller, B. A.; Koszinski, S.; Wehrhan, M.; Sommer, M.

2014-11-01

The distribution of soil organic carbon (SOC) can be variable at small analysis scales, but consideration of its role in regional and global issues demands the mapping of large extents. There are many different strategies for mapping SOC, among which are to model the variables needed to calculate the SOC stock indirectly or to model the SOC stock directly. The purpose of this research is to compare direct and indirect approaches to mapping SOC stocks from rule-based, multiple linear regression models applied at the landscape scale via spatial association. The final products for both strategies are high-resolution maps of SOC stocks (kg m-2), covering an area of 122 km2, with accompanying maps of estimated error. For the direct modelling approach, the estimated error map was based on the internal error estimations from the model rules. For the indirect approach, the estimated error map was produced by spatially combining the error estimates of component models via standard error propagation equations. We compared these two strategies for mapping SOC stocks on the basis of the qualities of the resulting maps as well as the magnitude and distribution of the estimated error. The direct approach produced a map with less spatial variation than the map produced by the indirect approach. The increased spatial variation represented by the indirect approach improved R2 values for the topsoil and subsoil stocks. Although the indirect approach had a lower mean estimated error for the topsoil stock, the mean estimated error for the total SOC stock (topsoil + subsoil) was lower for the direct approach. For these reasons, we recommend the direct approach to modelling SOC stocks be considered a more conservative estimate of the SOC stocks' spatial distribution.

Experimental Warming Aggravates Degradation-Induced Topsoil Drought in Alpine Meadows of The Qinghai-Tibetan Plateau

NASA Astrophysics Data System (ADS)

Xue, X.

2017-12-01

Climatic warming is presumed to cause topsoil drought by increasing evapotranspiration and water infiltration, and by progressively inducing land degradation in alpine meadows of the Qinghai-Tibetan Plateau. However, how soil moisture and temperature patterns of degraded alpine meadows respond to climate warming remains unclear. A six-year continuous warming experiment was carried out in both degraded and undegraded alpine meadows in the source region of the Yangtze River. The goal was to identify the effects of climatic warming and land degradation on soil moisture (θ), soil surface temperature (Tsfc), and soil temperature (Ts). In the present study, land degradation significantly reduced θ by 4.5-6.1% at a depth of 0-100 cm (P < 0.001), and increased the annual mean Tsfc by 0.8°C. Warming with an infrared heater (radiation output of 150 W m-2) significantly increased the annual mean Tsfc by 2.5°C (P < 0.001) and significantly increased θ by 4.7% at a depth of 40-60 cm. Experimental warming in degraded land reversed the positive effects of the infrared heater and caused the yearly average θ to decrease significantly by 3.7-8.1% at a depth of 0-100 cm. Our research reveals that land degradation caused a significant water deficit near the soil surface. Experimental warming aggravated topsoil drought caused by land degradation, intensified the magnitude of degradation, and caused a positive feedback in the degraded alpine meadow ecosystem. Therefore, an immediate need exists to restore degraded alpine meadow grasslands in the Qinghai-Tibetan Plateau in anticipation of a warmer future.

77 FR 61477 - Approval and Promulgation of Implementation Plans; State of Hawaii; Regional Haze Federal...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-09

... Maui is subjected to strong trade winds on many days, and plantation practices of clearing and tilling... harvest, the cane fields are left bare and the loose topsoil is picked up by the trade winds and carried...

Nickel speciation in several serpentine (ultramafic) topsoils via bulk synchrotron-based techniques

USDA-ARS?s Scientific Manuscript database

Serpentine soils are extensively studied because of their unique soil chemical properties and flora. They commonly have high magnesium-to-calcium ratios and elevated concentrations of trace metals including nickel, cobalt, and chromium. Several nickel hyperaccumulator plants are native to serpenti...

SUPERCRITICAL FLUID EXTRACTION OF POLYCYCLIC AROMATIC HYDROCARBON MIXTURES FROM CONTAMINATED SOILS

EPA Science Inventory

Highly contaminated (with PAHs) topsoils were extracted with supercritical CO₂ to determine the feasibility and mechanism of supercritical fluid extraction (SFE). Effect of SCF density, temperature, cosolvent type and amount, and of slurrying the soil with water were ...

The source apportionment of polycyclic aromatic hydrocarbons (PAHs) in the topsoil in Xiaodian sewage irrigation area, North of China.

PubMed

Li, Jia-Le; Wang, Yan-Xin; Zhang, Cai-Xiang; Dong, Yi-Hui; Du, Bin; Liao, Xiao-Ping

2014-12-01

31 topsoil samples were collected by grid method in Xiaodian sewage irrigation area, Taiyuan City, North of China. The concentrations of 16 kinds of polycyclic aromatic hydrocarbons (PAHs) were determined by gas chromatograph coupled with mass spectrum. Generally speaking, the distribution order of PAHs in the area is: those with five and six rings > those with four rings > those with two and three rings. Source apportionment shows a significant zonation of the source of PAHs: the civil coal pollution occurred in the north part, the local and far factory pollution happened in the middle area and the mixed pollution sources from coal and wood combustion, automotive emission, presented in the south area. The distribution of PAHs has a definite relationship with the sewage water flow and soil adsorption. The related coefficient between PAHs and physicochemical property showed there was a negative correlation between pH, silt, clay and PAHs while there was a positive correlation between total organic carbon, sand and PAHs.

Observation of radioactive iodine ((131)I, (129)I) in cropland soil after the Fukushima nuclear accident.

PubMed

Fujiwara, Hideshi

2016-10-01

During the early stages of the Fukushima nuclear accident, the temporal variations of (131)I deposited on the ground and of (131)I accumulated in cropland soil were monitored at a fixed location in Japan. Moreover, concentrations of long-lived radioactive iodine ((129)I) in atmospheric deposits and soil were measured to examine the feasibility of retrospectively reconstructing (131)I levels from the levels of accident-derived (129)I. The exceptionally high levels of (131)I in deposits and soil were attributed to rainfall-related deposition of radionuclides. In the crop field studied, the losses of deposited (131)I and (129)I due to volatilization were small. The atomic ratio (129)I/(131)I in the topsoil corresponded to the same ratio in deposits. The (131)I concentrations measured in the topsoil were very consistent with the (131)I concentrations reconstructed from the (129)I concentrations in the soil. Copyright © 2016 Elsevier B.V. All rights reserved.

Reclamation of the Wahsatch gathering system pipeline in southwestern Wyoming and northeastern Utah

DOE Office of Scientific and Technical Information (OSTI.GOV)

Strickland, D.; Dern, G.; Johnson, G.

1996-12-31

The Union Pacific Resources Company (UPRC) constructed a 40.4 mile pipeline in 1993 in Summit and Rich Countries, Utah and Uinta County, Wyoming. The pipeline collects and delivers natural gas from six existing wells to the Whitney Canyon Processing Plant north of Evanston, Wyoming. We describe reclamation of the pipeline, the cooperation received from landowners along the right-of-way, and mitigation measures implemented by UPRC to minimize impacts to wildlife. The reclamation procedure combines a 2 step topsoil separation, mulching with natural vegetation, native seed mixes, and measures designed to reduce the visual impacts of the pipeline. Topsoil is separated intomore » the top 4 inches of soil material, when present. The resulting top dressing is rich in native seed and rhizomes allowing a reduced seeding rate. The borders of the right-of-way are mowed in a curvilinear pattern to reduce the straight line effects of landowner cooperation on revegetation. Specifically, following 2 years of monitoring, significant differences in plant cover (0.01« less

30 CFR 817.22 - Topsoil and subsoil.

Code of Federal Regulations, 2011 CFR

2011-07-01

...— (i) Occur at the site of small structures, such as power poles, signs, or fence lines; or (ii) Will... contaminants and unnecessary compaction that would interfere with revegetation; (iii) Be protected from wind... disturbances will result from facilities such as support facilities and preparation plants and where...

30 CFR 816.22 - Topsoil and subsoil.

Code of Federal Regulations, 2011 CFR

2011-07-01

... site of small structures, such as power poles, signs, or fence lines; or (ii) Will not destroy the... unnecessary compaction that would interfere with revegetation; (iii) Be protected from wind and water erosion... from facilities such as support facilities and preparation plants and where stockpiling of materials...

30 CFR 817.22 - Topsoil and subsoil.

Code of Federal Regulations, 2010 CFR

2010-07-01

...— (i) Occur at the site of small structures, such as power poles, signs, or fence lines; or (ii) Will... contaminants and unnecessary compaction that would interfere with revegetation; (iii) Be protected from wind... disturbances will result from facilities such as support facilities and preparation plants and where...

30 CFR 816.22 - Topsoil and subsoil.

Code of Federal Regulations, 2010 CFR

2010-07-01

... site of small structures, such as power poles, signs, or fence lines; or (ii) Will not destroy the... unnecessary compaction that would interfere with revegetation; (iii) Be protected from wind and water erosion... from facilities such as support facilities and preparation plants and where stockpiling of materials...

Factors to consider in developing variable rate seeding prescriptions

USDA-ARS?s Scientific Manuscript database

Soil hydraulic properties influence many of the ecological functions of soil. The objectives of this study were to determine the influence of topsoil thickness on soil hydraulic properties for grain and perennial grass production systems. The experiment was carried out at the Soil Productivity Asses...

Influence of wind-induced air pressure fluctuations on topsoil gas concentrations within a Scots pine forest

NASA Astrophysics Data System (ADS)

Mohr, Manuel; Laemmel, Thomas; Maier, Martin; Schindler, Dirk

2017-04-01

Commonly it is assumed that soil gas transport is dominated by molecular diffusion. Few recent studies indicate that the atmosphere above the soil triggers non-diffusive gas transport processes in the soil, which can enhance soil gas transport and therefore soil gas efflux significantly. During high wind speed conditions, the so called pressure pumping effect has been observed: the enhancement of soil gas transport through dynamic changes in the air pressure field above the soil. However, the amplitudes and frequencies of the air pressure fluctuations responsible for pressure pumping are still uncertain. Moreover, an in situ observation of the pressure pumping effect is still missing. To investigate the pressure pumping effect, airflow measurements above and below the canopy of a Scots pine forest and high-precision relative air pressure measurements were conducted in the below-canopy space and in the soil over a measurement period of 16 weeks. To monitor the soil gas transport, a newly developed gas measurement system was used. The gas measurement system continuously injects helium as a tracer gas into the soil until a diffusive steady state is reached. With the steady state concentration profile of the tracer gas, it is possible to inversely model the gas diffusion coefficient profile of the soil. If the gas diffusion coefficient profile differed from steady state, we deduced that the soil gas transport is not only diffusive, but also influenced by non-diffusive processes. Results show that the occurrence of small air pressure fluctuations is strongly dependent on the mean above-canopy wind speed. The wind-induced air pressure fluctuations have mean amplitudes up to 10 Pa and lie in the frequency range 0.01-0.1 Hz. To describe the pumping motion of the air pressure field, the pressure pumping coefficient (PPC) was defined as the mean change in pressure per second. The PPC shows a clear quadratic dependence on mean above-canopy wind speed. Empirical modelling of the measured topsoil helium concentration demonstrated that the PPC is the most important predictor for changes in the topsoil helium concentration. Comparison of time periods with high PPC and periods of low PPC showed that the soil gas diffusion coefficient in depths between 5-10 cm increased up to 30% during periods of high PPC compared to steady state. Thus, the air pressure fluctuations observed in the atmosphere and described by the PPC penetrate into the soil and influence the topsoil gas transport.

Topsoil organic carbon content of Europe, a new map based on a generalised additive model

NASA Astrophysics Data System (ADS)

de Brogniez, Delphine; Ballabio, Cristiano; Stevens, Antoine; Jones, Robert J. A.; Montanarella, Luca; van Wesemael, Bas

2014-05-01

There is an increasing demand for up-to-date spatially continuous organic carbon (OC) data for global environment and climatic modeling. Whilst the current map of topsoil organic carbon content for Europe (Jones et al., 2005) was produced by applying expert-knowledge based pedo-transfer rules on large soil mapping units, the aim of this study was to replace it by applying digital soil mapping techniques on the first European harmonised geo-referenced topsoil (0-20 cm) database, which arises from the LUCAS (land use/cover area frame statistical survey) survey. A generalized additive model (GAM) was calibrated on 85% of the dataset (ca. 17 000 soil samples) and a backward stepwise approach selected slope, land cover, temperature, net primary productivity, latitude and longitude as environmental covariates (500 m resolution). The validation of the model (applied on 15% of the dataset), gave an R2 of 0.27. We observed that most organic soils were under-predicted by the model and that soils of Scandinavia were also poorly predicted. The model showed an RMSE of 42 g kg-1 for mineral soils and of 287 g kg-1 for organic soils. The map of predicted OC content showed the lowest values in Mediterranean countries and in croplands across Europe, whereas highest OC content were predicted in wetlands, woodlands and in mountainous areas. The map of standard error of the OC model predictions showed high values in northern latitudes, wetlands, moors and heathlands, whereas low uncertainty was mostly found in croplands. A comparison of our results with the map of Jones et al. (2005) showed a general agreement on the prediction of mineral soils' OC content, most probably because the models use some common covariates, namely land cover and temperature. Our model however failed to predict values of OC content greater than 200 g kg-1, which we explain by the imposed unimodal distribution of our model, whose mean is tilted towards the majority of soils, which are mineral. Finally, average OC content predictions for each land cover class compared well between models, with our model always showing smaller standard deviations. We concluded that the chosen model and covariates are appropriate for the prediction of OC content in European mineral soils. We presented in this work the first map of topsoil OC content at European scale based on a harmonised soil dataset. The associated uncertainty map shall support the end-users in a careful use of the predictions.

Transformation of goethite/ferrihydrite to hematite and maghemite under temperate humid conditions in Denmark

NASA Astrophysics Data System (ADS)

Nørnberg, P.; Finster, K.; Gunnlaugsson, H. P.; Jensen, S. K.; Merrison, J. P.; Vendelboe, A. L.

2012-04-01

At a number of sandy soil sites in Mid Jutland, Denmark, with iron content of 1-2%, very red spots (Munsell colour: dusky red 10R 3/4) of a few square meters are found. These spots are most likely due to burning events. After the fire ashes raised pH. This dispersed silt and clay size soil particles which were then transported with seepage water down into lower soil horizons. These particles contain hematite and maghemite due to influence of the fire. However, a long-standing unresolved question is how hematite and maghemite can also be present along with goethite and ferrihydrite, in the same geographical region, and in extended areas with high iron content (8-40 %) in the topsoil. Hematite and particularly maghemite would normally not be expected to form under the temperate humid Danish climate, but be interpreted as the result of high temperature as found in tropical regions or as seen in soils exposed to fire. The high iron content most likely has its origin in pyrite dissolution in top of the groundwater zone in deeper Miocene deposits. From there Fe2+ is brought to the surface by the groundwater, and in wells oxidized by meeting the atmosphere and precipitated as two line ferrihydrite. This is later transformed into goethite. However, along with these two minerals hematite and maghemite are present in the topsoil around the well area. Forest fires would be a likely explanation to the hematite and maghemite. But a body of evidence argues against these sites having been exposed to fire. 1) The pH in the topsoil is 3.6 - 4.8 and thus not raised by ashes. 2) No charcoal is present. 3) There is no indication of fire outside the high iron content areas. 4) Goethite is present along with hematite and maghemite in microparticles, and the mineralogical zonation produced in a forest fire is not seen. The natural sites contain a uniform mixture of goethite/ferrihydrite, hematite and maghemite down to 20 cm depth. An experimental forest fire left charcoal and ashes at the topsoil, produced high pH, mineral zonation and decreased organic matter content, all of which is in contrast to the natural sites. In the freshly precipitated iron materials iron oxidizers as Gallionella sp. were found, but also iron reducing Geobachter sp.were present. Microbial activity might have influenced the mineral transformations.

Evaluation of organic matter addition and incorporation on steep cut slopes : phase I, literature review and potential applicable equipment evaluation.

DOT National Transportation Integrated Search

2003-08-01

Erosion of steep highway cut slopes in Montana is the consequence of poor vegetation development in : nutrient-poor growth media resulting from highway construction where topsoil cannot physically be : replaced due to slope steepness. A literature re...

Topsoil thickness effects on phosphorus and potassium dynamics on claypan soils

USDA-ARS?s Scientific Manuscript database

Due to variable depth to claypan (DTC) across landscapes, nutrient supply from subsoils, and crop removal, precise P and K fertilizer management on claypan soil fields can be difficult. Therefore, a study was performed to determine if DTC derived from soil apparent electrical conductivity (ECa) coul...

Claypan depth effect on soil phosphorus and potassium dynamics

USDA-ARS?s Scientific Manuscript database

Understanding the effects of fertilizer addition and crop removal on long-term change in spatially-variable soil test P (STP) and soil test K (STK) is crucial for maximizing the use of grower inputs on claypan soils. Using apparent electrical conductivity (ECa) to estimate topsoil depth (or depth to...

Long term stability of microbial diversity and activity potential in severely disturbed arid lands of the southwest

USDA-ARS?s Scientific Manuscript database

Arid land cryptobiotic soil crusts govern water infiltration, soil aggregate stability and nutrient cycling between soil microbial communities and vascular plants. Surface mining involves removal of topsoil and associated crust and storage in mixed mounds for extended periods. The exposed subsoil an...

7 CFR 650.20 - Reviewing and commenting on EIS's prepared by other agencies.

Code of Federal Regulations, 2010 CFR

2010-01-01

... readily available. Field office technical guides, soil surveys, field investigation reports, and other...) The suitability or limitations of the soils for the proposed action. Would an alternative route... control measures? Will lack of erosion control cause air pollution? Is the stockpiling of topsoil for...

Evaluation of organic matter addition and incorporation on steep cut slopes : phase II, test plot construction and performance monitoring.

DOT National Transportation Integrated Search

2007-04-01

Erosion of steep highway cut slopes in Montana is often times the consequence of poor vegetation development : in nutrient-poor growth media resulting from highway construction where topsoil cannot physically be replaced : due to slope steepness. Top...

Greening from the Top Down.

ERIC Educational Resources Information Center

Oberndorfer, Erica

2002-01-01

Green roofs, with their topsoil and plants, improve insulation, filter air, reduce water runoff, and provide habitat for urban wildlife. They are compatible with schools because they save energy; schools' flat roofs are conducive to greening; and green roofs can be outdoor classrooms for botany, ecology, and energy efficiency. Although scarce in…

Long-term impact of land management in soil biological processes can be assessed by fingerprint of dissolved organic carbon and peroxidase activity in topsoil and subsoil

NASA Astrophysics Data System (ADS)

Hernandez-Soriano, Maria C.; Maclean, Jamie L.; Dalal, Ram C.; Menzies, Neal W.; Kopittke, Peter M.

2015-04-01

The dissolved organic carbon (DOC) is a highly dynamic pool, directly related to biological functions and to the stabilization of organic carbon (OC) through interaction with the mineral phase. Therefore, the characterization of the main components of DOC can be linked to the metabolic status of soil and the turnover of OC and provides a sensitive approach to evaluate the impact of land use on OC turnover in soils. Accordingly, the objective of this study was to derive relationships between DOC characteristics and biochemical activity in soils under contrasting land management. The soil solution was isolated from topsoil and subsoil for three soils (Vertisol, Ferralsol, Acrisol, World Reference Base 2014) collected from undisturbed areas and from a location(s) immediately adjacent which has a long history of agricultural, pasture or afforestation use (>20 years) by centrifugation at 4000 rpm (20 min, 25 °C. The fingerprint of DOC was obtained to identify OC functionalities by spectrofluorometric analyses and Excitation-Emission matrices (EEM) were obtained for all samples. The excitation wavelengths were increased from 250 to 400 nm in 5-nm steps for each excitation wavelength, and emission was detected from 250 to 500 nm in 0.5-nm steps and. Humification index (HIX), freshness index (FrI), fluorescence index (FI) and redox index (RI) were derived from the EEMs. Extracellular laccase activity was examined by monitoring the oxidation of 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) at 420 nm. The EEMs revealed a depletion of the humic-like component (250Acrisol>Ferralsol and was always higher for the topsoils compared to the corresponding subsoils. Overall, results indicate that land management has a strong impact on soil biological activity. Importantly, such impact is directly linked to changes in the composition of soil OC, particularly the transformation of OC inputs into oxidized products that can contribute to OC build up in soil. For the first time, we have utilized DOC fingerprinting and extracellular laccase activity as complementary techniques to examine changes in OC speciation in soil solutions. This approach provides a suitable link between variations in biological functions and OC dynamics.

Liriodendron growth on native and stripmine soils

Treesearch

W. Clark Ashby

2003-01-01

Liriodendron seedlings were planted each spring and fall for 5 years on unmined lands, ungraded spoils, graded to approximate original contour (AOC), and graded to contour with "topsoil" replaced. Survival was greatest on unmined lands and height greatest on ungraded ridge and valley spoil. No Liriodendron seedlings survived on AOC graded mine land. A few...

Effect of topsoil thickness on soil water infiltration in corn-soybean rotation and switchgrass production systems

USDA-ARS?s Scientific Manuscript database

Switchgrass and corn are sometimes used as a resource for biofuel production. The effect of production management systems on water infiltration is very critical in claypan landscape to increase production as well as minimize economic and environmental risks. The objective of this study was to evalua...

Soil water infiltration affected by biofuel and grain crop production systems in claypan landscape

USDA-ARS?s Scientific Manuscript database

The effect of soil management systems on water infiltration is very crucial within claypan landscapes to maximize production as well as minimize environmental risks. The objective of this study was to assess the effect of topsoil thickness on water infiltration in claypan soils for grain and biofuel...

Machine for row-mulching logging slash to enhance site- a concept

Treesearch

P. Koch; D.W. McKenzie

1977-01-01

Proposes that stumps, tops, and branches residual after logging pine plantations be hogged to build mulch beds spaced on about 2.5-m centers, thereby eliminating pile and bum operations. Growth of seedlings planted through mulch beds should be accelerated because of moisture conservation, weed suppression, and minimum disturbance of topsoil.

Soil Erosion. LC Science Tracer Bullet.

ERIC Educational Resources Information Center

Buydos, John F., Comp.

Soil erosion is the detachment and movement of topsoil or soil material from the upper part of the soil profile. It may occur in the form of rill, gully, sheet, or wind erosion. Agents of erosion may be water, wind, glacial ice, agricultural implements, machinery, and animals. Soil conservation measures require a thorough understanding of the…

78 FR 19434 - Effluent Limitations Guidelines and Standards for the Construction and Development Point Source...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-01

... channels or similar measures * * * Conveyance systems should be designed to withstand the velocities of... process as they are needed. For example, a sediment basin may be designed to accept water from several... minimizing soil compaction and preserving topsoil requirements. These requirements are designed to reduce the...

Influence of soil phosphorus and manure on phosphorus leaching in Swedish topsoils

USDA-ARS?s Scientific Manuscript database

In Sweden, subsurface transport of phosphorus (P) represents the primary pathway of concern to surface water quality. While strong relationships have been consistently observed between P in surface runoff and soil test P, there have been mixed findings linking P in leachate with soil test P. To expl...

Amazing Grazing.

ERIC Educational Resources Information Center

Peterson, Cris

Countless acres of grasslands stretch across the American West. Centuries ago, bison roamed the range freely and lived off the grass. By the 19th century, herds of cattle grazed the same land. Over time, much of the original grassland was either plowed and planted or trampled to dust, causing the topsoil to dry up and blow away. Today many…

30 CFR 715.16 - Topsoil handling.

Code of Federal Regulations, 2010 CFR

2010-07-01

... as the surface soil layers. Where the A horizon is less than 6 inches, a 6-inch layer that includes... replaced as the surface soil layer. (3) Where necessary to obtain soil productivity consistent with... amounts and analyses as determined by soil tests shall be applied to the surface soil layer so that it...

30 CFR 715.16 - Topsoil handling.

Code of Federal Regulations, 2011 CFR

2011-07-01

... as the surface soil layers. Where the A horizon is less than 6 inches, a 6-inch layer that includes... replaced as the surface soil layer. (3) Where necessary to obtain soil productivity consistent with... amounts and analyses as determined by soil tests shall be applied to the surface soil layer so that it...

30 CFR 715.16 - Topsoil handling.

Code of Federal Regulations, 2014 CFR

2014-07-01

... as the surface soil layers. Where the A horizon is less than 6 inches, a 6-inch layer that includes... replaced as the surface soil layer. (3) Where necessary to obtain soil productivity consistent with... amounts and analyses as determined by soil tests shall be applied to the surface soil layer so that it...

30 CFR 715.16 - Topsoil handling.

Code of Federal Regulations, 2012 CFR

2012-07-01

... as the surface soil layers. Where the A horizon is less than 6 inches, a 6-inch layer that includes... replaced as the surface soil layer. (3) Where necessary to obtain soil productivity consistent with... amounts and analyses as determined by soil tests shall be applied to the surface soil layer so that it...

30 CFR 715.16 - Topsoil handling.

Code of Federal Regulations, 2013 CFR

2013-07-01

... as the surface soil layers. Where the A horizon is less than 6 inches, a 6-inch layer that includes... replaced as the surface soil layer. (3) Where necessary to obtain soil productivity consistent with... amounts and analyses as determined by soil tests shall be applied to the surface soil layer so that it...

Machine for row-mulching logging slash to enhance site-a concept

Treesearch

Peter Koch; Dan W. McKenzie

1975-01-01

Proposes that stumps, tops, and branches residual after logging pine plantations be hogged to build mulch beds spaced on about 2.5-m centers, thereby eliminating pile and burn operations. Growth of seedlings planted through mulch beds should be accelerated because of moisture conservation, weed suppression, and minimum disturbance of topsoil.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Panagiotakis, I.; Dermatas, D.; Vatseris, C.

We conducted a forensic investigation with the aim of decoupling the contribution of geogenic and anthropogenic Cr(VI) sources in the wider area of Thiva. Groundwater and topsoil samples were collected from two Cr(VI) groundwater plumes of 160 μg/L and 75 μg/L. A series of evidence support the view that the origin of Cr(VI) detected in groundwater is mainly geogenic. These are: (a) the presence of Cr in topsoil of the wider area, (b) the moderate Cr(VI) groundwater concentrations, (c) the high Ni levels within the Cr(VI) plumes, (d) the predominance of Mn(IV), which is a prerequisite for Cr(III) oxidation tomore » Cr(VI), and (e) the absence of co-contaminants. This study also revealed that, although both Cr(VI) plumes are clearly of geogenic origin, the plume with the elevated Cr(VI) values, in the north of Thiva town, exhibits also an anthropogenic component, which can potentially be attributed to the alkaline environment associated with the old uncontrolled landfill of Thiva and the industrial cluster located in this area.« less

The global dispersion of pathogenic microorganisms by dust storms and its relevance to agriculture: Chapter 1

USGS Publications Warehouse

Gonzalez-Martin, Cristina; Teigell-Perez, Nuria; Valladares, Basilio; Griffin, Dale W.

2014-01-01

Dust storms move an estimated 500–5000 Tg of soil through Earth’s atmosphere every year. Dust-storm transport of topsoils may have positive effects such as fertilization of aquatic and terrestrial ecosystems and the evolution of soils in proximal and distal environments. Negative effects may include the stripping of nutrient-rich topsoils from source regions, sandblasting of plant life in downwind environments, the fertilization of harmful algal blooms, and the transport of toxins (e.g., metals, pesticides, herbicides, etc.) and pathogenic microorganisms. With respect to the long-range dispersion of microorganisms and more specifically pathogens, research is just beginning to demonstrate the quantity and diversity of organisms that can survive this type of transport. Most studies to date have utilized different assays to identify microorganisms and microbial communities using predominately culture-based, and more recently nonculture-based, methodologies. There is a clear need for international-scale research efforts that apply standardized methods to advance this field of science. Here we present a review of dust-borne microorganisms with a focus on their relevance to agronomy.

Source identification of soil mercury in the Spanish islands.

PubMed

Rodríguez Martín, José Antonio; Carbonell, Gregoria; Nanos, Nikos; Gutiérrez, Carmen

2013-02-01

This study spatially analysed the relation between mercury (Hg) content in soil and Hg in rock fragment for the purpose of assessing natural soil Hg contribution compared with Hg from human inputs. We present the Hg content of 318 soil and rock fragment samples from 11 islands distributed into two Spanish archipelagos (the volcanic Canary Islands [Canaries] and the Mediterranean Balearic [Balearic] islands). Assumedly both are located far enough away from continental Hg sources to be able to minimise the effects of diffuse pollution. Physical and chemical soil properties were also specified for the samples. Hg contents were significantly greater in the Balearic limestone soils (61 μg kg(-1)) than in the volcanic soils of the Canaries (33 μg kg(-1)). Hg levels were also greater in topsoil than in rocky fragments, especially on the Balearics. The soil-to-rock ratios varied between 1 and 30. Interestingly, the highest topsoil-to-rock Hg ratio (>16 ×) was found in the vicinity of a coal-fired power plant in Majorca, whereas no similar areas in the Canary archipelago were identified.

Soil erosion risk assessment using interviews, empirical soil erosion modeling (RUSLE) and fallout radionuclides in a volcanic crater lake watershed subjected to land use change, western Uganda

NASA Astrophysics Data System (ADS)

De Crop, Wannes; Ryken, Nick; Tomma Okuonzia, Judith; Van Ranst, Eric; Baert, Geert; Boeckx, Pascal; Verschuren, Dirk; Verdoodt, Ann

2017-04-01

Population pressure results in conversion of natural vegetation to cropland within the western Ugandan crater lake watersheds. These watersheds however are particularly prone to soil degradation and erosion because of the high rainfall intensity and steep topography. Increased soil erosion losses expose the aquatic ecosystems to excessive nutrient loading. In this study, the Katinda crater lake watershed, which is already heavily impacted by agricultural land use, was selected for an explorative study on its (top)soil characteristics - given the general lack of data on soils within these watersheds - as well as an assessment of soil erosion risks. Using group discussions and structured interviews, the local land users' perceptions on land use, soil quality, soil erosion and lake ecology were compiled. Datasets on rainfall, topsoil characteristics, slope gradient and length, and land use were collected. Subsequently a RUSLE erosion model was run. Results from this empirical erosion modeling approach were validated against soil erosion estimates based on 137Cs measurements.

Nano-hydroxyapatite alleviates the detrimental effects of heavy metals on plant growth and soil microbes in e-waste-contaminated soil.

PubMed

Wei, Liu; Wang, Shutao; Zuo, Qingqing; Liang, Shuxuan; Shen, Shigang; Zhao, Chunxia

2016-06-15

The crude recycling activities of e-waste have led to the severe and complex contamination of e-waste workshop topsoil (0-10 cm) by heavy metals. After nano-hydroxyapatite (NHAp) application in June 2013, plant and soil samples were obtained in November 2013, December 2013, March 2014 and June 2014. The results showed that NHAp effectively reduced the concentration of CaCl2-extractable Pb, Cu, Cd, and Zn in the topsoil and significantly reduced the metal content in ryegrass and also increased the plant biomass compared with that of the control. Moreover, the concentrations of CaCl2-extractable metals in the soil decreased with increasing NHAp. NHAp application also increased the activities of soil urease, phosphatase and dehydrogenase. Moreover, the soil bacterial diversity and community structure were also altered after NHAp application. Particularly, Stenotrophomonas sp. and Bacteroides percentages were increased. Our work proves that NHAp application can alleviate the detrimental effects of heavy metals on plants grown in e-waste-contaminated soil and soil enzyme activities, as well as soil microbial diversity.

Impacts of urbanization on the distribution of heavy metals in soils along the Huangpu River, the drinking water source for Shanghai.

PubMed

Bai, Yang; Wang, Min; Peng, Chi; Alatalo, Juha M

2016-03-01

We investigated the horizontal and vertical distribution of heavy metals (Hg, Pb, Zn, Cu, Cd, As, Ni, and Cr) in soils in the water source protection zone for Shanghai to study the origins of these metals, their connections with urbanization, and their potential risk posed on the ecosystem. Determination of metal concentrations in 50 topsoil samples and nine soil profiles indicated that Hg, Pb, Zn, and Cu were present in significantly higher concentrations in topsoil than in deep soil layers. The spatial distributions of Hg, Pb, Zn, and Cu and contamination hotspots for these metals in the study area were similar to those near heavy industries and urban built-up areas. Emissions from automobiles resulted in increased soil concentrations of Cu, Pb, and Zn along roadsides, while high concentrations of Hg in the soil resulted from recent atmospheric deposition. Calculation of the potential ecological risk indicated that the integrative risk of these heavy metals in most areas was low, but a few sites surrounding high density of factories showed moderate risks.

Diffusive gradients in thin films measurement of sulfur stable isotope variations in labile soil sulfate.

PubMed

Hanousek, Ondrej; Santner, Jakob; Mason, Sean; Berger, Torsten W; Wenzel, Walter W; Prohaska, Thomas

2016-11-01

A diffusive gradient in thin films (DGT) technique, based on a strongly basic anion exchange resin (Amberlite IRA-400), was successfully tested for 34 S/ 32 S analysis in labile soil sulfate. Separation of matrix elements (Na, K, and Ca) that potentially cause non-spectral interferences in 34 S/ 32 S analysis by MC ICP-MS (multi-collector inductively coupled plasma-mass spectrometry) during sampling of sulfate was demonstrated. No isotopic fractionation caused by diffusion or elution of sulfate was observed below a resin gel disc loading of ≤79 μg S. Above this threshold, fractionation towards 34 S was observed. The method was applied to 11 different topsoils and one mineral soil profile (0-100 cm depth) and compared with soil sulfate extraction by water. The S amount and isotopic ratio in DGT-S and water-extractable sulfate correlated significantly (r 2  = 0.89 and r 2  = 0.74 for the 11 topsoils, respectively). The systematically lower 34 S/ 32 S isotope ratios of the DGT-S were ascribed to mineralization of organic S.

Unleaded gasoline as a significant source of Pb emissions in the Subarctic.

PubMed

Chrastný, Vladislav; Šillerová, Hana; Vítková, Martina; Francová, Anna; Jehlička, Jan; Kocourková, Jana; Aspholm, Paul E; Nilsson, Lars O; Berglen, Tore F; Jensen, Henning K B; Komárek, Michael

2018-02-01

After the phasing out of leaded gasoline, Pb emissions to the atmosphere dramatically decreased, and other sources became more significant. The contribution of unleaded gasoline has not been sufficiently recognized; therefore, we evaluated the impact of Pb from unleaded gasoline in a relatively pristine area in Subarctic NE Norway. The influence of different endmembers (Ni slag and concentrate from the Nikel smelter in Russia, PM 10 filters, and traffic) on the overall Pb emissions was determined using various environmental samples (snow, lichens, and topsoils) and Pb isotope tracing. We found a strong relationship between Pb in snow and the Ni smelter. However, lichen samples and most of the topsoils were contaminated by Pb originating from the current use of unleaded gasoline originating from Russia. Historical leaded and recent unleaded gasoline are fully distinguishable using Pb isotopes, as unleaded gasoline is characterized by a low radiogenic composition ( 206 Pb/ 207 Pb = 1.098 and 208 Pb/ 206 Pb = 2.060) and remains an unneglectable source of Pb in the region. Copyright © 2017 Elsevier Ltd. All rights reserved.

Detection and differentiation of pollution in urban surface soils using magnetic properties in arid and semi-arid regions of northwestern China.

PubMed

Wang, Bo; Xia, Dunsheng; Yu, Ye; Jia, Jia; Xu, Shujing

2014-01-01

Increasing urbanization and industrialization over the world has caused many social and environmental problems, one of which drawing particular concern is the soil pollution and its ecological degradation. In this study, the efficiency of magnetic methods for detecting and discriminating contaminates in the arid and semi-arid regions of northwestern China was investigated. Topsoil samples from six typical cities (i.e. Karamay, Urumqi, Lanzhou, Yinchuan, Shizuishan and Wuhai) were collected and a systematic analysis of their magnetic properties was conducted. Results indicate that the topsoil samples from the six cities were all dominated by coarse low-coercivity magnetite. In addition, the average magnetite contents in the soils from Urumqi and Lanzhou were shown to be much higher than those from Karamay, Yinchuan, Shizuishan and Wuhai, and they also have relatively higher χlf and χfd% when compared with cities in eastern China. Moreover, specific and distinctive soil pollution signals were identified at each sampling site using the combined various magnetic data, reflecting distinct sources. Industrial and traffic-derived pollution was dominant in Urumqi and Lanzhou, in Yinchuan industrial progress was observed to be important with some places affected by vehicle emission, while Karamay, Shizuishan and Wuhai were relatively clean. The magnetic properties of these latter three cities are significantly affected by both anthropogenic pollution and local parent materials from the nearby Gobi desert. The differences in magnetic properties of topsoil samples affected by mixed industrial and simplex traffic emissions are not obvious, but significant differences exist in samples affected by simplex industrial/vehicle emissions and domestic pollution. The combined magnetic analyses thus provide a sensitive and powerful tool for classifying samples according to likely sources, and may even provide a valuable diagnostic tool for discriminating among different cities. Copyright © 2013 Elsevier Ltd. All rights reserved.

Site- and horizon-specific patterns of microbial community structure and enzyme activities in permafrost-affected soils of Greenland

PubMed Central

Gittel, Antje; Bárta, Jiří; Kohoutová, Iva; Schnecker, Jörg; Wild, Birgit; Čapek, Petr; Kaiser, Christina; Torsvik, Vigdis L.; Richter, Andreas; Schleper, Christa; Urich, Tim

2014-01-01

Permafrost-affected soils in the Northern latitudes store huge amounts of organic carbon (OC) that is prone to microbial degradation and subsequent release of greenhouse gasses to the atmosphere. In Greenland, the consequences of permafrost thaw have only recently been addressed, and predictions on its impact on the carbon budget are thus still highly uncertain. However, the fate of OC is not only determined by abiotic factors, but closely tied to microbial activity. We investigated eight soil profiles in northeast Greenland comprising two sites with typical tundra vegetation and one wet fen site. We assessed microbial community structure and diversity (SSU rRNA gene tag sequencing, quantification of bacteria, archaea and fungi), and measured hydrolytic and oxidative enzyme activities. Sampling site and thus abiotic factors had a significant impact on microbial community structure, diversity and activity, the wet fen site exhibiting higher potential enzyme activities and presumably being a hot spot for anaerobic degradation processes such as fermentation and methanogenesis. Lowest fungal to bacterial ratios were found in topsoils that had been relocated by cryoturbation (“buried topsoils”), resulting from a decrease in fungal abundance compared to recent (“unburied”) topsoils. Actinobacteria (in particular Intrasporangiaceae) accounted for a major fraction of the microbial community in buried topsoils, but were only of minor abundance in all other soil horizons. It was indicated that the distribution pattern of Actinobacteria and a variety of other bacterial classes was related to the activity of phenol oxidases and peroxidases supporting the hypothesis that bacteria might resume the role of fungi in oxidative enzyme production and degradation of phenolic and other complex substrates in these soils. Our study sheds light on the highly diverse, but poorly-studied communities in permafrost-affected soils in Greenland and their role in OC degradation. PMID:25360132

Microbial nitrogen dynamics in organic and mineral soil horizons along a latitudinal transect in western Siberia

PubMed Central

Wild, Birgit; Schnecker, Jörg; Knoltsch, Anna; Takriti, Mounir; Mooshammer, Maria; Gentsch, Norman; Mikutta, Robert; Alves, Ricardo J Eloy; Gittel, Antje; Lashchinskiy, Nikolay; Richter, Andreas

2015-01-01

Soil N availability is constrained by the breakdown of N-containing polymers such as proteins to oligopeptides and amino acids that can be taken up by plants and microorganisms. Excess N is released from microbial cells as ammonium (N mineralization), which in turn can serve as substrate for nitrification. According to stoichiometric theory, N mineralization and nitrification are expected to increase in relation to protein depolymerization with decreasing N limitation, and thus from higher to lower latitudes and from topsoils to subsoils. To test these hypotheses, we compared gross rates of protein depolymerization, N mineralization and nitrification (determined using 15N pool dilution assays) in organic topsoil, mineral topsoil, and mineral subsoil of seven ecosystems along a latitudinal transect in western Siberia, from tundra (67°N) to steppe (54°N). The investigated ecosystems differed strongly in N transformation rates, with highest protein depolymerization and N mineralization rates in middle and southern taiga. All N transformation rates decreased with soil depth following the decrease in organic matter content. Related to protein depolymerization, N mineralization and nitrification were significantly higher in mineral than in organic horizons, supporting a decrease in microbial N limitation with depth. In contrast, we did not find indications for a decrease in microbial N limitation from arctic to temperate ecosystems along the transect. Our findings thus challenge the perception of ubiquitous N limitation at high latitudes, but suggest a transition from N to C limitation of microorganisms with soil depth, even in high-latitude systems such as tundra and boreal forest. Key Points We compared soil N dynamics of seven ecosystems along a latitudinal transectShifts in N dynamics suggest a decrease in microbial N limitation with depthWe found no decrease in microbial N limitation from arctic to temperate zones PMID:26693204

Input of easily available organic C and N stimulates microbial decomposition of soil organic matter in arctic permafrost soil

PubMed Central

Wild, Birgit; Schnecker, Jörg; Alves, Ricardo J. Eloy; Barsukov, Pavel; Bárta, Jiří; Čapek, Petr; Gentsch, Norman; Gittel, Antje; Guggenberger, Georg; Lashchinskiy, Nikolay; Mikutta, Robert; Rusalimova, Olga; Šantrůčková, Hana; Shibistova, Olga; Urich, Tim; Watzka, Margarete; Zrazhevskaya, Galina; Richter, Andreas

2014-01-01

Rising temperatures in the Arctic can affect soil organic matter (SOM) decomposition directly and indirectly, by increasing plant primary production and thus the allocation of plant-derived organic compounds into the soil. Such compounds, for example root exudates or decaying fine roots, are easily available for microorganisms, and can alter the decomposition of older SOM (“priming effect”). We here report on a SOM priming experiment in the active layer of a permafrost soil from the central Siberian Arctic, comparing responses of organic topsoil, mineral subsoil, and cryoturbated subsoil material (i.e., poorly decomposed topsoil material subducted into the subsoil by freeze–thaw processes) to additions of 13C-labeled glucose, cellulose, a mixture of amino acids, and protein (added at levels corresponding to approximately 1% of soil organic carbon). SOM decomposition in the topsoil was barely affected by higher availability of organic compounds, whereas SOM decomposition in both subsoil horizons responded strongly. In the mineral subsoil, SOM decomposition increased by a factor of two to three after any substrate addition (glucose, cellulose, amino acids, protein), suggesting that the microbial decomposer community was limited in energy to break down more complex components of SOM. In the cryoturbated horizon, SOM decomposition increased by a factor of two after addition of amino acids or protein, but was not significantly affected by glucose or cellulose, indicating nitrogen rather than energy limitation. Since the stimulation of SOM decomposition in cryoturbated material was not connected to microbial growth or to a change in microbial community composition, the additional nitrogen was likely invested in the production of extracellular enzymes required for SOM decomposition. Our findings provide a first mechanistic understanding of priming in permafrost soils and suggest that an increase in the availability of organic carbon or nitrogen, e.g., by increased plant productivity, can change the decomposition of SOM stored in deeper layers of permafrost soils, with possible repercussions on the global climate. PMID:25089062

Magnetic properties of alluvial soils polluted with heavy metals

NASA Astrophysics Data System (ADS)

Dlouha, S.; Petrovsky, E.; Boruvka, L.; Kapicka, A.; Grison, H.

2012-04-01

Magnetic properties of soils, reflecting mineralogy, concentration and grain-size distribution of Fe-oxides, proved to be useful tool in assessing the soil properties in terms of various environmental conditions. Measurement of soil magnetic properties presents a convenient method to investigate the natural environmental changes in soils as well as the anthropogenic pollution of soils with several risk elements. The effect of fluvial pollution with Cd, Cu, Pb and Zn on magnetic soil properties was studied on highly contaminated alluvial soils from the mining/smelting district (Příbram; CZ) using a combination of magnetic and geochemical methods. The basic soil characteristics, the content of heavy metals, oxalate, and dithionite extractable iron were determined in selected soil samples. Soil profiles were sampled using HUMAX soil corer and the magnetic susceptibility was measured in situ, further detailed magnetic analyses of selected distinct layers were carried out. Two types of variations of magnetic properties in soil profiles were observed corresponding to indentified soil types (Fluvisols, and Gleyic Fluvisols). Significantly higher values of topsoil magnetic susceptibility compared to underlying soil are accompanied with high concentration of heavy metals. Sequential extraction analysis proved the binding of Pb, Zn and Cd in Fe and Mn oxides. Concentration and size-dependent parameters (anhysteretic and isothermal magnetization) were measured on bulk samples in terms of assessing the origin of magnetic components. The results enabled to distinguish clearly topsoil layers enhanced with heavy metals from subsoil samples. The dominance of particles with pseudo-single domain behavior in topsoil and paramagnetic/antiferromagnetic contribution in subsoil were observed. These measurements were verified with room temperature hysteresis measurement carried out on bulk samples and magnetic extracts. Thermomagnetic analysis of magnetic susceptibility measured on magnetic extracts indicated the presence of magnetite/maghemite in the uppermost layers, and strong mineralogical transformation of iron oxyhydroxides during heating. Magnetic techniques give valuable information about the soil Fe oxides, which are useful for investigation of the environmental effects in soil. Key words: magnetic methods, Fe oxides, pollution, alluvial soils.

Aged Riverine Particulate Organic Carbon in Four UK Catchments

NASA Astrophysics Data System (ADS)

Adams, Jessica; Tipping, Edward; Bryant, Charlotte; Helliwell, Rachel; Toberman, Hannah; Quinton, John

2016-04-01

The riverine transport of particulate organic matter (POM) is a significant flux in the carbon cycle, and affects macronutrients and contaminants. We used radiocarbon to characterise POM at 9 riverine sites of four UK catchments (Avon, Conwy, Dee, Ribble) over a one-year period. High-discharge samples were collected on three or four occasions at each site. Suspended particulate matter (SPM) was obtained by centrifugation, and the samples were analysed for carbon isotopes. Concentrations of SPM and SPM organic carbon (OC) contents were also determined, and were found to have a significant negative correlation. For the 7 rivers draining predominantly rural catchments, PO14C values, expressed as percent modern carbon absolute (pMC), varied little among samplings at each site, and there was no significant difference in the average values among the sites. The overall average PO14C value for the 7 sites of 91.2 pMC corresponded to an average age of 680 14C years, but this value arises from the mixing of differently-aged components, and therefore significant amounts of organic matter older than the average value are present in the samples. Although topsoil erosion is probably the major source of the riverine POM, the average PO14C value is appreciably lower than topsoil values (which are typically 100 pMC). This is most likely explained by inputs of older subsoil OC from bank erosion, or the preferential loss of high-14C topsoil organic matter by mineralisation during riverine transport. The significantly lower average PO14C of samples from the River Calder (76.6 pMC), can be ascribed to components containing little or no radiocarbon, derived either from industrial sources or historical coal mining, and this effect is also seen in the River Ribble, downstream of its confluence with the Calder. At the global scale, the results significantly expand available information for PO14C in rivers draining catchments with low erosion rates.

Spatial distribution and concentration of sulfur in relation to vegetation cover and soil properties on a reclaimed sulfur mine site (Southern Poland).

PubMed

Likus-Cieślik, Justyna; Pietrzykowski, Marcin; Szostak, Marta; Szulczewski, Melanie

2017-02-01

This work aims to assess the spatial distribution and concentration of sulfur in the topsoil layer and to determine the relationships between sulfur concentration, soil pH, soil electrical conductivity, and plant cover at the reforested site of the former sulfur mine (Southern Poland). Soil samples were collected from 0 to 20 cm (topsoil) from a total of 86 sampling points in a regular square grid with sides of 150 m. Plant cover was assayed in circular plots with an area of 100 m 2 , divided into a woody plant layer and herbaceous plant layer. Soil properties such as particle size distribution, pH in KCl and H 2 O, soil electrical conductivity (EC), soil organic carbon (SOC), total nitrogen (N T ), and total sulfur (S T ) were determined. The degree of soil contamination with sulfur was assessed based on the guidelines of the Institute of Soil Science and Plant Cultivation (IUNG), Poland. The results indicate that remediation and application of lime were not fully effective in spatial variation, because 33 points with sulfur contamination above 500 mg kg -1 were observed. These spots occurred irregularly in the topsoil horizons. This high sulfur concentration in the soil did not result in severe acidification (below 4.5) in all cases, most likely due to neutralization from the application of high doses of flotation lime. High vegetative cover occurred at some points with high soil sulfur concentrations, with two points having S concentration above 40,000 mg kg -1 and tree cover about 60%. Numerous points with high soil EC above 1500 μS cm -1 as well as limited vegetation and high soil sulfur concentrations, however, indicate that the reclamation to forest is still not completely successful.

No Significant Changes in Topsoil Carbon in the Grasslands of Northern China Between the 1980s and 2000s

NASA Astrophysics Data System (ADS)

Liu, S.; Yang, Y.; Shen, H.; Hu, H.; Zhao, X.; Li, H.; Liu, T.; Fang, J.

2017-12-01

The grasslands of northern China store a large amount of soil organic carbon (SOC), and the small changes in SOC stock could significantly affect the regional C cycle. However, recent estimates of SOC changes in this region are highly controversial. In this study, we examined and mapped the changes in the SOC density (SOCD) in the upper 30 cm of the grasslands of northern China between the 1980s and 2000s, using an improved approach that integrates field-based measurements into machine learning algorithms (artificial neural network and random forest). The random forest-generated SOCD averaged 5.55 kg C m-2 in the 1980s and 5.53 kg C m-2 in the 2000s. The change ranged between -0.17 and 0.22 kg C m-2 at the 95% confidence level, suggesting that the overall SOCD did not change significantly during the study period. However, the change in SOCD exhibited large regional variability. The topsoil of the Inner Mongolian grasslands experienced a significant C loss (4.86 vs. 4.33 kg C m-2), whereas that of the Xinjiang grasslands exhibited an accumulation of C (5.55 vs. 6.46 kg C m-2). In addition, the topsoil C in the Tibetan alpine grasslands remained relatively stable (6.12 vs. 6.06 kg C m-2). A comparison of different grassland types indicated that SOCD exhibited significant decreases in typical steppe, whereas showed increases in mountain meadow, and were stable in the remaining grasslands (alpine meadow, alpine steppe, mountain steppe and desert steppe). Climate variables were shown to be the main determines of the change of SOCD. Increases in precipitation could lead to SOC increase in temperate grasslands and SOC loss in alpine grasslands, while climate warming is likely to cause SOC loss in temperate grasslands. Overall, our study shows that northern grasslands in China remained a neutral SOC sink between the 1980s and 2000s.

Rehabilitation of a lignite mine-disturbed area in the Indian Desert

USGS Publications Warehouse

Sharma, K.D.; Kumar, P.; Gough, L.P.; SanFilipo, J.R.

2004-01-01

Extensive lignite mining in the Indian (Thar) Desert commenced within the past decade. Accompanying extraction of this valuable resource there have been visible, important environmental impacts. The resultant land degradation has prompted concern from both public and regulatory bodies. This research assesses the success of rehabilitation plans implemented to revegetate a lignite mine-disturbed area, near the village of Giral in western Rajasthan State. Rehabilitation success was achieved within the environmental constraints of this northwest Indian hot-desert ecosystem using a combination of: (1) backfilling (abandoned pits) with minespoil and of covering the backfilled-surfaces with fresh topsoil to a thickness of about 0??30 m; (2) use of micro-catchment rainwater harvesting (MCWH) technique; (3) soil profile modification approaches; (4) plant establishment methodologies; and (5) the selection of appropriate germplasm material (trees, shrubs and grasses). Preliminary results indicate that the resulting vegetative cover will be capable of self-perpetuation under natural conditions while at the same time meeting the land-use requirements of the local people. The minespoil is alkaline in nature and has high electrical conductance. The average content of organic carbon, N, P and K is lower than in the regional topsoil. However, the concentration of Ca, Mg, Na and total S in the minespoil is much higher than in the topsoil. Further, the spoil material has no biological activity. Enhanced plant growth was achieved in MCWH plots, compared to control plots, where minespoil moisture storage was improved by 18-43 per cent. The rehabilitation protocol used at the site appears to have been successful because, in addition to the planted species, desirable native invasive species have become established. This study developed methods for the rehabilitation of lignite mine-disturbed areas and has also resulted in an understanding of rehabilitation processes in arid regions with an emphasis on the long-term monitoring of rehabilitation success. ?? 2004 John Wiley and Sons, Ltd.

Effect of nanohydroxyapatite on cadmium leaching and environmental risks under simulated acid rain.

PubMed

Zhao, Chenchen; Ren, Shuxia; Zuo, Qingqing; Wang, Shutao; Zhou, Yapeng; Liu, Wei; Liang, Shuxuan

2018-06-15

Cadmium (Cd) contamination in soil is a global environmental pollution issue. Nanohydroxyapatite (NHAP) has been used in soil remediation to immobilize cadmium in contaminated soils. However, the effect of acid rain on the export of cadmium from topsoil and its behavior in deep soil and leachate is unclear. In this study, column experiments and development of parsimonious model were performed to estimate Cd leaching behavior from topsoil and environmental risk of groundwater after 0.5% NHAP remediation. Four leaching events were performed and total Cd, different fractions of Cd determined by sequential extraction procedure and pH were determined for each leaching. The results show that with the export of Cd in topsoil, the total Cd concentration in soil at different depths had the following vertical distributions: 0-5 cm > 5-10 cm > 10-15 cm > 15-20 cm. NHAP treatment increased the soil pH and decreased Cd leaching loss by 56.45% compared to the control, and the results fit the parabolic diffusion model. With sequential extraction it was observed that NHAP application increased the residual fraction of cadmium in soil. After leaching, there was a positive correlation between soil pH and Cd concentration with regards to the exchangeable, reducible, oxidizable and residual Cd fractions. The parabolic diffusion model showed that Cd-contaminated soil with NHAP remediation is harmless to humans after sufficient remediation duration, whereas the resultant concentrations from the CK treatment could be toxic. The results indicate that nanohydroxyapatite could significantly reduce the bioavailability of cadmium and the environmental risk. However, the release of Ca and P from the dissolution of NHAP should be carefully studied as this will impact the mobilization of Cd or colloid Cd, and high leaching of P may result in P-induced eutrophication risk. Copyright © 2018 Elsevier B.V. All rights reserved.

Land-Use Conversion Changes the Multifractal Features of Particle-Size Distribution on the Loess Plateau of China

PubMed Central

Sun, Caili; Liu, Guobin; Xue, Sha

2016-01-01

Analyzing the dynamics of soil particle-size distributions (PSDs), soil nutrients, and erodibility are very important for understanding the changes of soil structure and quality after long-term land-use conversion. We applied multifractal Rényi spectra (Dq) and singularity spectra (f(α)) to characterize PSDs 35 years after conversions from cropland to shrubland with Caragana microphylla (shrubland I), shrubland with Hippophae rhamnoides (shrubland II), forested land, and grassland on the Loess Plateau of China. Multifractal parameters (capacity dimension (D0), entropy dimension (D1), D1/D0, correlation dimension (D2), and Hölder exponent of order zero (α0)) were used to analyze the changes of PSDs. Dq and f(α) characterized the PSDs well and sensitively represented the changes in PSDs after conversion. All types of land-use conversion significantly improved the properties of the topsoil (0–10 cm), but the effect of shrubland I and even forested land decreased with depth. All types of land-use conversion significantly increased D1 and D2 in the topsoil, and D1 and D2 in the 10–50 cm layers of shrubland II, forested land, and grassland and D1 in the 50–100 cm layers of shrubland II were significantly higher relative to the control. Both D1 and D2 were positively correlated with the contents of soil nutrients and fine particles and were negatively correlated with soil erosion, indicating that D1 and D2 were potential indices for quantifying changes in soil properties and erosion. In conclusion, all types of land-use conversion significantly improved the conditions of the topsoil, but conversion from cropland to shrubland II, forested land, and grassland, especially shrubland II and grassland, were more effective for improving soil conditions in deeper layers. PMID:27527201

[Distribution characteristics of soil organic carbon under different forest restoration modes on opencast coal mine dump].

PubMed

Wen, Yue-rong; Dang, Ting-hui; Tang, Jun; Li, Jun-chao

2016-01-01

The content and storage of soil organic carbon (SOC) were compared in six wood restoration modes and adjacent abandoned land on opencast coal mine dump, and the mechanisms behind the differences and their influencing factors were analyzed. Results showed that the contents of SOC in six wood lands were significantly higher (23.8%-53.2%) than that of abandoned land (1.92 g · kg⁻¹) at 0-10 cm soil depth, the index were significantly higher (5.8%-70.4%) at 10-20 cm soil depth than the abandoned land (1.39 g · kg⁻¹), and then the difference of the contents of SOC in the deep soil (20-100 cm) were not significant. The contents of SOC decreased with increase of soil depth, but the decreasing magnitude of the topsoil (0-20 cm) was higher than that of the deep soil (20-100 cm). Compared with the deep soil, the topsoil significant higer storage of SOC in different woods, the SOC storage decreased with the soil depth. Along the 0-100 cm soil layer, the storage of SOC in six wood lands higher (18.1%-42.4%) than that of the abandoned land (17.52 t · hm⁻²). The SOC storage of Amorpha fruticosa land (24.95 t · hm⁻²) was obviously higher than that in the other wood lands. The SOC storage in the shrub lands was 12.4% higher than that of the arbor woods. There were significantly positive correlations among forest litter, fine root biomass, soil water content and SOC on the dump. Consequently, different plantation restorations significantly improved the SOC level on the dump in 0-100 cm soil, especially the topsoil. But there was still a big gap about SOC level between the wood restoration lands and the original landform. To improve the SOC on opencast coal mine dump, A. fruticosa could be selected as the main wood vegetation.

CO(2) partial pressure and calcite saturation in springs - useful data for identifying infiltration areas in mountainous environments.

PubMed

Hilberg, Sylke; Brandstätter, Jennifer; Glück, Daniel

2013-04-01

Mountainous regions such as the Central European Alps host considerable karstified or fractured groundwater bodies, which meet many of the demands concerning drinking water supply, hydropower or agriculture. Alpine hydrogeologists are required to describe the dynamics in fractured aquifers in order to assess potential impacts of human activities on water budget and quality. Delineation of catchment areas by means of stable isotopes and hydrochemical data is a well established method in alpine hydrogeology. To achieve reliable results, time series of (at least) one year and spatial and temporal close-meshed data are necessary. In reality, test sites in mountainous regions are often inaccessible due to the danger of avalanches in winter. The aim of our work was to assess a method based on the processes within the carbonic acid system to delineate infiltration areas by means of single datasets consisting of the main hydrochemical parameters of each spring. In three geologically different mountainous environments we managed to classify the investigated springs into four groups. (1) High PCO2 combined with slight super-saturation in calcite, indicating relatively low infiltration areas. (2) Low PCO2 near atmospheric conditions in combination with calcite saturation, which is indicative of relatively high infiltration areas and a fractured aquifer which is not covered by topsoil layers. (3) High PCO2 in combination with sub-saturation in calcite, representing a shallow aquifer with a significant influence of the topsoil layer. (4) The fourth group of waters is characterized by low PCO2 and sub-saturation in calcite, which is interpreted as evidence for a shallow aquifer without significant influence of any hard rock aquifer or topsoil layer. This study shows that CO2-partial pressure can be an ideal natural tracer to estimate the elevation of infiltration areas, especially in non-karstified fractured groundwater bodies.

Distinguishing between old and modern permafrost sources in the northeast Siberian land-shelf system with compound-specific δ2H analysis

NASA Astrophysics Data System (ADS)

Vonk, Jorien E.; Tesi, Tommaso; Bröder, Lisa; Holmstrand, Henry; Hugelius, Gustaf; Andersson, August; Dudarev, Oleg; Semiletov, Igor; Gustafsson, Örjan

2017-08-01

Pleistocene ice complex permafrost deposits contain roughly a quarter of the organic carbon (OC) stored in permafrost (PF) terrain. When permafrost thaws, its OC is remobilized into the (aquatic) environment where it is available for degradation, transport or burial. Aquatic or coastal environments contain sedimentary reservoirs that can serve as archives of past climatic change. As permafrost thaw is increasing throughout the Arctic, these reservoirs are important locations to assess the fate of remobilized permafrost OC.

We here present compound-specific deuterium (δ2H) analysis on leaf waxes as a tool to distinguish between OC released from thawing Pleistocene permafrost (ice complex deposits; ICD) and from thawing Holocene permafrost (from near-surface soils). Bulk geochemistry (%OC; δ13C; %total nitrogen, TN) was analyzed as well as the concentrations and δ2H signatures of long-chain n-alkanes (C21 to C33) and mid- to long-chain n-alkanoic acids (C16 to C30) extracted from both ICD-PF samples (n = 9) and modern vegetation and O-horizon (topsoil-PF) samples (n = 9) from across the northeast Siberian Arctic. Results show that these topsoil-PF samples have higher %OC, higher OC / TN values and more depleted δ13C-OC values than ICD-PF samples, suggesting that these former samples trace a fresher soil and/or vegetation source. Whereas the two investigated sources differ on the bulk geochemical level, they are, however, virtually indistinguishable when using leaf wax concentrations and ratios. However, on the molecular isotope level, leaf wax biomarker δ2H values are statistically different between topsoil PF and ICD PF. For example, the mean δ2H value of C29 n-alkane was -246 ± 13 ‰ (mean ± SD) for topsoil PF and -280 ± 12 ‰ for ICD PF. With a dynamic isotopic range (difference between two sources) of 34 to 50 ‰; the isotopic fingerprints of individual, abundant, biomarker molecules from leaf waxes can thus serve as endmembers to distinguish between these two sources. We tested this molecular δ2H tracer along with another source-distinguishing approach, dual-carbon (δ13C-Δ14C) isotope composition of bulk OC, for a surface sediment transect in the Laptev Sea. Results show that general offshore patterns along the shelf-slope transect are similar, but the source apportionment between the approaches vary, which may highlight the advantages of either. This study indicates that the application of δ2H leaf wax values has potential to serve as a complementary quantitative measure of the source and differential fate of OC thawed out from different permafrost compartments.

GEMAS: Spatial pattern analysis of Ni by using digital image processing techniques on European agricultural soil data

NASA Astrophysics Data System (ADS)

Jordan, Gyozo; Petrik, Attila; De Vivo, Benedetto; Albanese, Stefano; Demetriades, Alecos; Sadeghi, Martiya

2017-04-01

Several studies have investigated the spatial distribution of chemical elements in topsoil (0-20 cm) within the framework of the EuroGeoSurveys Geochemistry Expert Group's 'Geochemical Mapping of Agricultural and Grazing Land Soil' project . Most of these studies used geostatistical analyses and interpolated concentration maps, Exploratory and Compositional Data and Analysis to identify anomalous patterns. The objective of our investigation is to demonstrate the use of digital image processing techniques for reproducible spatial pattern recognition and quantitative spatial feature characterisation. A single element (Ni) concentration in agricultural topsoil is used to perform the detailed spatial analysis, and to relate these features to possible underlying processes. In this study, simple univariate statistical methods were implemented first, and Tukey's inner-fence criterion was used to delineate statistical outliers. The linear and triangular irregular network (TIN) interpolation was used on the outlier-free Ni data points, which was resampled to a 10*10 km grid. Successive moving average smoothing was applied to generalise the TIN model and to suppress small- and at the same time enhance significant large-scale features of Nickel concentration spatial distribution patterns in European topsoil. The TIN map smoothed with a moving average filter revealed the spatial trends and patterns without losing much detail, and it was used as the input into digital image processing, such as local maxima and minima determination, digital cross sections, gradient magnitude and gradient direction calculation, second derivative profile curvature calculation, edge detection, local variability assessment, lineament density and directional variogram analyses. The detailed image processing analysis revealed several NE-SW, E-W and NW-SE oriented elongated features, which coincide with different spatial parameter classes and alignment with local maxima and minima. The NE-SW oriented linear pattern is the dominant feature to the south of the last glaciation limit. Some of these linear features are parallel to the suture zone of the Iapetus Ocean, while the others follow the Alpine and Carpathian Chains. The highest variability zones of Ni concentration in topsoil are located in the Alps and in the Balkans where mafic and ultramafic rocks outcrop. The predominant NE-SW oriented pattern is also captured by the strong anisotropy in the semi-variograms in this direction. A single major E-W oriented north-facing feature runs along the southern border of the last glaciation zone. This zone also coincides with a series of local maxima in Ni concentration along the glaciofluvial deposits. The NW-SE elongated spatial features are less dominant and are located in the Pyrenees and Scandinavia. This study demonstrates the efficiency of systematic image processing analysis in identifying and characterising spatial geochemical patterns that often remain uncovered by the usual visual map interpretation techniques.

30 CFR 817.83 - Coal mine waste: Refuse piles.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 3 2013-07-01 2013-07-01 false Coal mine waste: Refuse piles. 817.83 Section... ACTIVITIES § 817.83 Coal mine waste: Refuse piles. Refuse piles shall meet the requirements of § 817.81, the... removed from the disposal area prior to placement of coal mine waste. Topsoil shall be removed, segregated...

30 CFR 816.83 - Coal mine waste: Refuse piles.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 3 2014-07-01 2014-07-01 false Coal mine waste: Refuse piles. 816.83 Section... ACTIVITIES § 816.83 Coal mine waste: Refuse piles. Refuse piles shall meet the requirements of § 816.81, the... removed from the disposal area prior to placement of coal mine waste. Topsoil shall be removed, segregated...

30 CFR 817.83 - Coal mine waste: Refuse piles.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 3 2014-07-01 2014-07-01 false Coal mine waste: Refuse piles. 817.83 Section... ACTIVITIES § 817.83 Coal mine waste: Refuse piles. Refuse piles shall meet the requirements of § 817.81, the... removed from the disposal area prior to placement of coal mine waste. Topsoil shall be removed, segregated...

30 CFR 816.83 - Coal mine waste: Refuse piles.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 3 2013-07-01 2013-07-01 false Coal mine waste: Refuse piles. 816.83 Section... ACTIVITIES § 816.83 Coal mine waste: Refuse piles. Refuse piles shall meet the requirements of § 816.81, the... removed from the disposal area prior to placement of coal mine waste. Topsoil shall be removed, segregated...

30 CFR 817.83 - Coal mine waste: Refuse piles.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 3 2012-07-01 2012-07-01 false Coal mine waste: Refuse piles. 817.83 Section... ACTIVITIES § 817.83 Coal mine waste: Refuse piles. Refuse piles shall meet the requirements of § 817.81, the... removed from the disposal area prior to placement of coal mine waste. Topsoil shall be removed, segregated...

30 CFR 816.83 - Coal mine waste: Refuse piles.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Coal mine waste: Refuse piles. 816.83 Section... ACTIVITIES § 816.83 Coal mine waste: Refuse piles. Refuse piles shall meet the requirements of § 816.81, the... removed from the disposal area prior to placement of coal mine waste. Topsoil shall be removed, segregated...

30 CFR 816.83 - Coal mine waste: Refuse piles.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 3 2011-07-01 2011-07-01 false Coal mine waste: Refuse piles. 816.83 Section... ACTIVITIES § 816.83 Coal mine waste: Refuse piles. Refuse piles shall meet the requirements of § 816.81, the... removed from the disposal area prior to placement of coal mine waste. Topsoil shall be removed, segregated...

30 CFR 816.83 - Coal mine waste: Refuse piles.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 3 2012-07-01 2012-07-01 false Coal mine waste: Refuse piles. 816.83 Section... ACTIVITIES § 816.83 Coal mine waste: Refuse piles. Refuse piles shall meet the requirements of § 816.81, the... removed from the disposal area prior to placement of coal mine waste. Topsoil shall be removed, segregated...

30 CFR 817.83 - Coal mine waste: Refuse piles.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 3 2011-07-01 2011-07-01 false Coal mine waste: Refuse piles. 817.83 Section... ACTIVITIES § 817.83 Coal mine waste: Refuse piles. Refuse piles shall meet the requirements of § 817.81, the... removed from the disposal area prior to placement of coal mine waste. Topsoil shall be removed, segregated...

30 CFR 817.83 - Coal mine waste: Refuse piles.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Coal mine waste: Refuse piles. 817.83 Section... ACTIVITIES § 817.83 Coal mine waste: Refuse piles. Refuse piles shall meet the requirements of § 817.81, the... removed from the disposal area prior to placement of coal mine waste. Topsoil shall be removed, segregated...

Organic and inorganic amendments affect vegetation growth on an acidic minesoil

Treesearch

William T. Plass

1982-01-01

Organic amendments can be included in minesoil revegetation treatments to produce high-density ground covers or increase the yield of pasture and forage crops. They may provide an alternative to the "topsoiling" requirements under current surface-mining laws and regulations. In this study, shredded hardwood bark, composted municipal waste, and a tannery waste...

Maintaining adequate nutrient supply - Principles, decision-support tools, and best management practices [Chapter 6

Treesearch

Robert B. Harrison; Douglas A. Maguire; Deborah Page-Dumroese

2011-01-01

Maintaining adequate nutrient supply to maintain or enhance tree vigor and forest growth requires conservation of topsoil and soil organic matter. Sometimes nutrient amendments are also required to supplement inherent nutrient-pool limitations or replenish nutrients removed in harvested material. The goal is to maintain the productive potential of the soil and, when...

Evaluating topsoil depth effects on phosphorus and potassium nutrient dynamics of grain and switchgrass production systems

USDA-ARS?s Scientific Manuscript database

Understanding the effects of fertilizer addition and crop removal on long-term change in soil test phosphorus (STP) and soil test potassium (STK) is crucial for maximizing the use of grower inputs on claypan soils. Due to variable nutrient supply from subsoils and variable crop removal across fields...

Restoration of tropical moist forest on bauxite mined lands in the Brazilian Amazon

Treesearch

John A Parrotta; Oliver H. Knowles

1999-01-01

We evaluated forest structure and composition in 9- to 13-year-old stands established on a bauxite-mined site at Trombetas (Pará), Brazil, using four different reforestation techniques following initial site preparation and topsoil replacement. These techniques included reliance on natural forest regeneration, mixed commercial species plantings of mostly exotic timber...

Collection and production of indigenous plant material for national park restoration

Treesearch

Mark Majerus

1999-01-01

The National Park Service is taking the "Restoration" approach to reestablishing native plant communities by salvaging topsoil and by seeding and planting native indigenous plant materials. In this way, they are making every effort to protect the genetic integrity of the often unique native plant resource. Since 1985, Yellowstone and Glacier National Parks...

Action at the Grassroots: Fighting Poverty and Environmental Decline. Worldwatch Paper 88.

ERIC Educational Resources Information Center

Durning, Alan B.

There are many forces of environmental and economic decline that endanger our communities and planet. These have caused a global threat which is very complex. The pressure to feed increasing numbers of people helps cause high rates of topsoil loss which results in decreased agricultural productivity. As poorer nations attempt to fight these…

76 FR 13429 - Notice of Availability of Final Environmental Impact Statement for the Proposed Blackfoot Bridge...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-11

... 1B would incorporate a layer of impermeable material called a laminated geosynthetic clay liner, or... inches of topsoil; 1 foot of weathered alluvium cover material; 6 inches of drainage/protective layer material; GCLL; 6 inches of a protective sub-grade layer (weathered alluvium or other earthen material...

Radiation dosimetry on revegetated uranium mill tailings in western South Dakota

Treesearch

Mark A. Rumble

1986-01-01

Measurement of gamma radiation using thermoluminescent dosimeters on three uranium mill tailings areas and a control area showed exposure rates below ground depended on the amount and type of soil covering. Covering tailings with 30 cm of shale and 60 cm of topsoil reduced gamma radiation exposure belowground to rates similar to the control area. Soil covering of 30 cm...

The economic cost of upland and gully erosion on subsistence agriculture for a watershed in the Ethiopian highlands

USDA-ARS?s Scientific Manuscript database

This paper quantifies the cost of erosion; it uses nutrient replacement cost to value topsoil nutrient depletion, daily wage rate to monetize the opportunity cost of labour due to gully erosion and local market price to quantify the lost animal and cash crop trees. Soil erosion rate is estimated fro...

Protecting the source: Tools to evaluate fuel treatment cost vs. water quality protection

Treesearch

Brian Cooke; William Elliot; Mary Ellen Miller; Mark Finney; Matthew Thompson

2016-01-01

High-intensity wildfires are one of the leading causes of severe soil erosion in western U.S. watersheds. This erosion can lead to disruptive deposits of sediment in reservoirs and water supply systems. Fuel treatments such as controlled burns and forest thinning can reduce wildfire intensity and help preserve topsoil. But while these treatments are generally...

Tree planters` notes, Volume 46, Number 2, Spring 1995. Quarterly report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nisley, R.

1995-12-31

;Contents: Certified Seed and Artificial Forest Regeneration; Missoula Technology and Development Center`s 1995 Nursery and Reforestation Programs; Trees Grow Better With Water; Botrytis cinerea Carried by Adult Fungus Gnats (Diptera: Sciaridae) in Container Nurseries; Oak Seedling Root and Shoot Growth on Restored Topsoil; Improved Vegetative Propagation of Scouler Willow; Estimating Poller Yield From Western White Pine: Preliminary Studies.

Explanation of pole blight from responses of seedlings grown in modified environments

Treesearch

Charles D. Leaphart; Ed F. Wicker

1966-01-01

Seedlings of Douglas fir, grand fir, western larch, western red cedar, and western white pine were grown in modified environments for four growing seasons to see whether characteristic growth responses of roots and shoots might suggest a cause for pole blight of white pine. Environments included three soil profiles (topsoil, hardpan, and rock) and two moisture regimes...

Response of transplanted aspen to irrigation and weeding on a Colorado reclaimed surface coal mine

Treesearch

Robert C. Musselman; Wayne D. Shepperd; Frederick W. Smith; Lance A. Asherin; Brian W. Gee

2012-01-01

Successful re-establishment of aspen (Populus tremuloides Michx.) on surface-mined lands in the western United States is problematic because the species generally regenerates vegetatively by sprouting from parent roots in the soil; however, topsoil is removed in the mining process. Previous attempts to plant aspen on reclaimed mine sites have failed because...

Red Maple (Acer rubrum L.) Growth and Foliar Nutrient Responses to Soil Fertility Level and Water Regime

Treesearch

C. H. Pham; Howard G. Halverson; Gordon M. Heisler

1978-01-01

Red maple (Acer rubrum L.) seedlings were grown in a greenhouse using three treatments: two soil horizons, two soil moisture regimes, and three nutrient levels. Fertilization increased growth under moist conditions on the more fertile topsoil. Under dry conditions, fertilization had no effect on growth in subsoil, and slightly increased growth in...

Stereoselective accumulations of hexachlorocyclohexanes (HCHs) are correlated with Sphingomonas spp. in agricultural soils across China.

PubMed

Xu, Yang; Niu, Lili; Qiu, Jiguo; Zhou, Yuting; Lu, Huijie; Liu, Weiping

2018-05-02

The wide usage of hexachlorocyclohexanes (HCHs) as pesticides has caused soil pollution and adverse health effects through direct contact or bioaccumulation in the food chain. This study quantified major HCH isomers in farmland topsoils across China, and evaluated their correlations with microbial community structure, function, and abiotic variables (e.g., moisture, pH, and temperature). Recalcitrant β-HCH was more abundant than α-, γ-, and δ-HCHs, and α-HCH enantiomeric fractions (EF) were larger than 0.5, indicating preferential degradation of (-)-α-HCH. Sphingomonas was not only a predominant population (especially in samples collected in the south), but also a promising biomarker indicating total- and β-HCH residuals, and EF values of α-HCH. Soil moisture and temperature were among the most influential factors that structured the diversity and function of soil microbial communities. The results suggested that increasing soil moisture (in the range of 5-45%) would benefit the growth of HCH-degrading populations and the enrichment of HCH-degradation related pathways. Revealing the site-specific relationships between topsoil physical, chemical, and microbial properties will benefit the in situ bioremediation of farmlands with relatively low HCH residuals across the world. Copyright © 2018 Elsevier Ltd. All rights reserved.

Environmental Persistence of Bacillus anthracis and Bacillus subtilis Spores

PubMed Central

Wood, Joseph P.; Meyer, Kathryn M.; Kelly, Thomas J.; Choi, Young W.; Rogers, James V.; Riggs, Karen B.; Willenberg, Zachary J.

2015-01-01

There is a lack of data for how the viability of biological agents may degrade over time in different environments. In this study, experiments were conducted to determine the persistence of Bacillus anthracis and Bacillus subtilis spores on outdoor materials with and without exposure to simulated sunlight, using ultraviolet (UV)-A/B radiation. Spores were inoculated onto glass, wood, concrete, and topsoil and recovered after periods of 2, 14, 28, and 56 days. Recovery and inactivation kinetics for the two species were assessed for each surface material and UV exposure condition. Results suggest that with exposure to UV, decay of spore viability for both Bacillus species occurs in two phases, with an initial rapid decay, followed by a slower inactivation period. The exception was with topsoil, in which there was minimal loss of spore viability in soil over 56 days, with or without UV exposure. The greatest loss in viable spore recovery occurred on glass with UV exposure, with nearly a four log10 reduction after just two days. In most cases, B. subtilis had a slower rate of decay than B. anthracis, although less B. subtilis was recovered initially. PMID:26372011

CO2 and fertility affect growth and reproduction but not susceptibility to aphids in field grown Solanum ptycanthum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Long, T.M.

1995-09-01

In general, C3 annual plants respond positively in terms of growth, reproduction and biomass accrued when grown under elevated levels of atmospheric carbon dioxide. However, most studies documenting this response have been conducted in growth chambers where plants can be reared under conditions free form environmental stressors such as nutrient and water constraints, UV exposure and damage from pests. During the 1993 fieldseason, I grew 200 individuals of Solanum ptycanthum in an array of 10 outdoor, open-topped CO2 enclosures (5 @ 700 ppm CO2) at the University of Michigan Biological Station in Pellston, MI. Half of the plants were grownmore » in a 50;50 mix of native C-horizon soil and topsoil (low fertility); the other half were grown in 100% topsoil (high-fertility). Plants were censused throughout the growing season for flower and fruit production, growth rate and degree of infestation of aphids. Fertility and CO2 both significantly affected production of flowers and fruits, but only fertility was significantly related to vegetative growth. Aphid infestation varied significantly among enclosures, but was not related to CO2 or fertility.« less

Vertical nutrient and trace element migration in cambisoils after application of residues from anaerobic digestion of pig manure

NASA Astrophysics Data System (ADS)

Sager, Manfred; Unterfrauner, Hans

2013-04-01

Cambisols sampled in alpine pastures were packed into soil columns in order to monitor downward migration of nutrient and trace elements, applied within the residue from anaerobic digestion of a pig manure. 2 rain events per week were simulated. The manure added substantial amounts of K, ammonium, Na, Ca, P, S, Cl, B, Zn and Cu to the soil, whereas Mg, Mn, Ni, Cr, Pb, Cd and V were at the same level. In the eluates, total elemental composition as well as nitrate and ammonium were monitored. Addition of soluble Fe (at 1000 mg/l as FeCl3) decreased the release of soluble sulphate, but had no significant effect on the release of Fe and P. During subsequent rain events, exchangeable K remained enriched in the topsoil, wheras total sulfur moved to deeper layers. After 8 weeks, the columns were dismantled and analyzed for quasi-total and mobile fractions. Both in topsoils and subsoils, manure addition finally increased soil pH in case of low P soils, but decreased soil pH in case of high pH soils. Effects of manure applications on groundwater formation processes will be discussed.

Waste rock revegetation: Evaluation of nutrient and biological amendments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meikle, T.W.; Lu, S.; Barta, J.P.

1999-07-01

Lack of salvaged topsoil for the reclamation of historical waste rock piles is a common problem in the arid Great Basin region. Utilization of amended waste rock as a growth media could reduce further disturbance resulting from topsoil harvest, minimize hauling costs, and potentially allow for the use of a higher quality material for plant growth. Getchell Gold Corporation initiated a study in 1995 to determine the suitability of waste rock substrates to support plant growth following application of nutrient and biological amendments. Three nutrient amendments and a biological seed treatment were evaluation for use in establishing vegetative cover onmore » three distinct waste rock substrates. Completely randomized blocks were placed on the three substrates. Treatments included organic fertilizers (Biosol and Gro-Power), a mineral fertilizer (16-20-0), and Azospirillum bacterial inoculant, plus controls. The seed mix consisted of Agropyron riparium, Agropyron spicatum, Elymus cinereus, Poa secunda, and Sitanion hystrix. Canopy and ground cover were monitored for three growing seasons. Conclusions from the study are: (1) two of the three substrates supported plant growth following amendment with organic fertilizers; (2) organic fertilizers increased cover substantially over the mineral fertilizer; and (3) Azospirillum had no effect on canopy cover.« less

Atmospheric bulk deposition of polycyclic aromatic hydrocarbons in Shanghai: Temporal and spatial variation, and global comparison.

PubMed

Feng, Daolun; Liu, Ying; Gao, Yi; Zhou, Jinxing; Zheng, Lirong; Qiao, Gang; Ma, Liming; Lin, Zhifen; Grathwohl, Peter

2017-11-01

Atmospheric deposition leads to accumulation of atmospheric polycyclic aromatic hydrocarbons (PAHs) on urban surfaces and topsoils. To capture the inherent variability of atmospheric deposition of PAHs in Shanghai's urban agglomeration, 85 atmospheric bulk deposition samples and 7 surface soil samples were collected from seven sampling locations during 2012-2014. Total fluxes of 17 PAHs were 587-32,300 ng m -2 day -1 , with a geometric mean of 2600 ng m -2 day -1 . The deposition fluxes were categorized as moderate to high on a global scale. Phenanthrene, fluoranthene and pyrene were major contributors. The spatial distribution of deposition fluxes revealed the influence of urbanization/industrialization and the relevance of local emissions. Meteorological conditions and more heating demand in cold season lead to a significant increase of deposition rates. Atmospheric deposition is the principal pathway of PAHs input to topsoils and the annual deposition load in Shanghai amounts to ∼4.5 tons (0.7 kg km -2 ) with a range of 2.5-10 tons (0.4-1.6 kg km -2 ). Copyright © 2017 Elsevier Ltd. All rights reserved.

Use of Lead Isotopes to Identify Sources of Metal and Metalloid Contaminants in Atmospheric Aerosol from Mining Operations

PubMed Central

Félix, Omar I.; Csavina, Janae; Field, Jason; Rine, Kyle P.; Sáez, A. Eduardo; Betterton, Eric A.

2014-01-01

Mining operations are a potential source of metal and metalloid contamination by atmospheric particulate generated from smelting activities, as well as from erosion of mine tailings. In this work, we show how lead isotopes can be used for source apportionment of metal and metalloid contaminants from the site of an active copper mine. Analysis of atmospheric aerosol shows two distinct isotopic signatures: one prevalent in fine particles (< 1 μm aerodynamic diameter) while the other corresponds to coarse particles as well as particles in all size ranges from a nearby urban environment. The lead isotopic ratios found in the fine particles are equal to those of the mine that provides the ore to the smelter. Topsoil samples at the mining site show concentrations of Pb and As decreasing with distance from the smelter. Isotopic ratios for the sample closest to the smelter (650 m) and from topsoil at all sample locations, extending to more than 1 km from the smelter, were similar to those found in fine particles in atmospheric dust. The results validate the use of lead isotope signatures for source apportionment of metal and metalloid contaminants transported by atmospheric particulate. PMID:25496740

Mixing of Marine and Terrestrial Sources of Strontium in Coastal Environments

NASA Astrophysics Data System (ADS)

Ryan, Saskia; Crowley, Quentin; Deegan, Eileen; Snoeck, Christophe

2017-04-01

87Sr/86Sr from bulk soils, soil extracts and plant material have been used to investigate and quantify the extent of marine-derived Sr in the terrestrial biosphere. Samples were collected along coastal transects and 87Sr/86Sr biosphere values (plant and soil) converge to marine values with increasing proximity to the coast. R2values indicate highly significant trends in certain regions. The National Soils Database (NSDB), TELLUS and TELLUS Border datasets, all of which are geochemical surveys have been employed to further test the extent of marine elemental contribution. Collectively these data cover all of Ireland and Northern Ireland, with varying degrees of sampling density. A strong spatial correlation exists between the Chemical Index of Alteration (CIA; (Al2O3-(CaO*+Na2O)-K2O)) in topsoil (CIA <60; 27% n = 11651) and areas of blanket peat. The enrichment of Ca and Na in these regions would suggest a significant marine geochemical contribution. Topsoil CIA can therefore be used to identify areas likely to feature significant marine inputs and identify regions where the 87Sr/86Sr budget may deviate from bedrock values.

Polycyclic aromatic hydrocarbons in soils from the Tibetan Plateau, China: distribution and influence of environmental factors.

PubMed

Wang, Shuang; Ni, Hong-Gang; Sun, Jian-Lin; Jing, Xin; He, Jin-Sheng; Zeng, Hui

2013-03-01

Thirty four sampling sites along an elevation transect in the Tibetan Plateau region were chosen. Soil cores were divided into several layers and a total of 175 horizon soil samples were collected from July to September 2011, for determination of polycyclic aromatic hydrocarbons (PAHs). The measured PAHs concentration in surface soils was 56.26 ± 45.84 ng g(-1), and the low molecular weight PAHs (2-3 rings) predominated, accounting for 48% and 35%. We analyzed the spatial (altitudinal and vertical) distribution of PAHs in soil, and explored the influence of related environmental factors. Total organic carbon (TOC) showed a controlling influence on the distribution of PAHs. PAH concentrations declined with soil depth, and the composition patterns of PAHs along soil depth indicated that the heavy PAHs tended to remain in the upper layers (0-10 cm), while the light fractions were transported downward more easily. PAHs inventories (8.77-57.92 mg m(-2)) for soil cores increased with mean annual precipitation, while the topsoil concentrations decreased with it. This implies that an increase in precipitation could transfer more PAHs from the atmosphere to the soil and further transport PAHs from the topsoil to deeper layers.

Black Carbon Contribution to Organic Carbon Stocks in Urban Soil.

PubMed

Edmondson, Jill L; Stott, Iain; Potter, Jonathan; Lopez-Capel, Elisa; Manning, David A C; Gaston, Kevin J; Leake, Jonathan R

2015-07-21

Soil holds 75% of the total organic carbon (TOC) stock in terrestrial ecosystems. This comprises ecosystem-derived organic carbon (OC) and black carbon (BC), a recalcitrant product of the incomplete combustion of fossil fuels and biomass. Urban topsoils are often enriched in BC from historical emissions of soot and have high TOC concentrations, but the contribution of BC to TOC throughout the urban soil profile, at a regional scale is unknown. We sampled 55 urban soil profiles across the North East of England, a region with a history of coal burning and heavy industry. Through combined elemental and thermogravimetic analyses, we found very large total soil OC stocks (31-65 kg m(-2) to 1 m), exceeding typical values reported for UK woodland soils. BC contributed 28-39% of the TOC stocks, up to 23 kg C m(-2) to 1 m, and was affected by soil texture. The proportional contribution of the BC-rich fraction to TOC increased with soil depth, and was enriched in topsoil under trees when compared to grassland. Our findings establish the importance of urban ecosystems in storing large amounts of OC in soils and that these soils also capture a large proportion of BC particulates emitted within urban areas.

Organic matter turnover in subsoils: current knowledge and future challenges

NASA Astrophysics Data System (ADS)

Marschner, Bernd

2014-05-01

In the past, carbon flux measurements and modelling have mostly considered the topsoil where C-concentrations, root densities and microbial activities are generally highest. However, depending on climate zone and land use, this soil compartment contains only 30-50% of the C-stocks of the first meter. If the deeper subsoil down to 3 m is also considered, the contribution of topsoil carbon stocks to total soil C-pools is only 20-40%. Another distinct property of subsoil organic matter is its high apparent 14C age. The 14C age of bulk soil organic matter below 30 cm depth generally increases continuously indicating mean residence times of several 103 to 104 years. Large pool size and high radiocarbon age suggest that subsoil OM has accumulated at very low rates over very long time periods and therefore appears to be very stable. In this review, several hypotheses for explaining why subsoil SOM is so seemingly old and inert are presented. These questions are being addressed in a recently granted German research unit consisting of 9 subprojects from all soil science disciplines using field measurements of C-fluxes, 14C analyses and conducting field and lab experiments.

Forensic investigation of a chromium(VI) groundwater plume in Thiva, Greece.

PubMed

Panagiotakis, I; Dermatas, D; Vatseris, C; Chrysochoou, M; Papassiopi, N; Xenidis, A; Vaxevanidou, K

2015-01-08

A forensic investigation was conducted with the aim of decoupling the contribution of geogenic and anthropogenic Cr(VI) sources in the wider area of Thiva. Groundwater and topsoil samples were collected from two Cr(VI) groundwater plumes of 160 μg/L and 75 μg/L. A series of evidence support the view that the origin of Cr(VI) detected in groundwater is mainly geogenic. These are: (a) the presence of Cr in topsoil of the wider area, (b) the moderate Cr(VI) groundwater concentrations, (c) the high Ni levels within the Cr(VI) plumes, (d) the predominance of Mn(IV), which is a prerequisite for Cr(III) oxidation to Cr(VI), and (e) the absence of co-contaminants. The present study also revealed that, although both Cr(VI) plumes are clearly of geogenic origin, the plume with the elevated Cr(VI) values, in the north of Thiva town, exhibits also an anthropogenic component, which can potentially be attributed to the alkaline environment associated with the old uncontrolled landfill of Thiva and the industrial cluster located in this area. Copyright © 2014 Elsevier B.V. All rights reserved.

Anthropogenic metal enrichment of snow and soil in north-eastern European Russia.

PubMed

Walker, T R; Young, S D; Crittenden, P D; Zhang, H

2003-01-01

Trace metal composition of winter snowpack, snow-melt filter residues and top-soil samples were determined along three transects through industrial towns in the Usa basin, North-East Russia: Inta, Usinsk and Vorkuta. Snow was analysed for Ag, Al, As, Ba, Cd, Co, Cr, Cu, Mn, Ni, Pb, Sr and Zn using ICP-MS (Ca and K by F-AAS for Vorkuta only), pH and acidity/alkalinity. Filter residues were analysed for: Al, Ba, Ca, Cd, Cu, K, Mg, Mn, Ni, Pb, Sr and Zn using F-AAS and GF-AAS; top-soil samples were analysed for Ba, Cu, Mg, Mn, Na, Ni, Pb, Sr, Zn using F-AAS. Results indicate elevated concentrations of elements associated with alkaline combustion ash around the coal mining towns of Vorkuta and Inta. There is little evidence of deposition around the gas and oil town of Usinsk. Atmospheric deposition in the vicinity of Vorkuta, and to a lesser extent Inta, added significantly to the soil contaminant loading as a result of ash fallout. Acid deposition was associated with pristine areas whereas alkaline combustion ash near to emission sources more than compensated for the acidity caused by SO2.

Spills of Hydraulic Fracturing Chemicals on Agricultural Topsoil: Biodegradation, Sorption, and Co-contaminant Interactions.

PubMed

McLaughlin, Molly C; Borch, Thomas; Blotevogel, Jens

2016-06-07

Hydraulic fracturing frequently occurs on agricultural land. Yet the extent of sorption, transformation, and interactions among the numerous organic frac fluid and oil and gas wastewater constituents upon environmental release is hardly known. Thus, this study aims to advance our current understanding of processes that control the environmental fate and toxicity of commonly used hydraulic fracturing chemicals. Poly(ethylene glycol) surfactants were completely biodegraded in agricultural topsoil within 42-71 days, but their transformation was impeded in the presence of the biocide glutaraldehyde and was completely inhibited by salt at concentrations typical for oil and gas wastewater. At the same time, aqueous glutaraldehyde concentrations decreased due to sorption to soil and were completely biodegraded within 33-57 days. While no aqueous removal of polyacrylamide friction reducer was observed over a period of 6 months, it cross-linked with glutaraldehyde, further lowering the biocide's aqueous concentration. These findings highlight the necessity to consider co-contaminant effects when we evaluate the risk of frac fluid additives and oil and gas wastewater constituents in agricultural soils in order to fully understand their human health impacts, likelihood for crop uptake, and potential for groundwater contamination.

Effects of aluminium water treatment residuals, used as a soil amendment to control phosphorus mobility in agricultural soils.

PubMed

Ulén, Barbro; Etana, Ararso; Lindström, Bodil

2012-01-01

Phosphorus (P) leaching from agricultural soils is a serious environmental concern. Application of aluminium water treatment residuals (Al-WTRs) at a rate of 20 Mg ha(-1) to clay soils from central Sweden significantly increased mean topsoil P sorption index (PSI) from 4.6 to 5.5 μmol kg(-1) soil. Mean degree of P saturation in ammonium lactate extract (DPS-AL) significantly decreased from 17 to 13%, as did plant-available P (P-AL). Concentrations of dissolved reactive P (DRP) decreased by 10-85% in leaching water with Al-WTR treatments after exposure of topsoil lysimeters to simulated rain. Soil aggregate stability (AgS) for 15 test soils rarely improved. Three soils (clay loam, silty loam and loam sand) were tested in greenhouse pot experiments. Aluminium-WTR application of 15 or 30 ton ha(-1) to loam sand and a clay loam with P-AL values of 80-100 mg kg(-1) soil significantly increased growth of Italian ryegrass when fertilised with P but did not significantly affect growth of spring barley on any soil. Al-WTR should only be applied to soils with high P fertility where improved crop production is not required.

The limitations of seedling growth and drought tolerance to novel soil substrates in arid systems: Implications for restoration success

NASA Astrophysics Data System (ADS)

Bateman, Amber; Lewandrowski, Wolfgang; Stevens, Jason; Muñoz-Rojas, Miriam

2016-04-01

Introduction With the limited knowledge available regarding the impact of drought on seedling growth, an understanding of seedling tolerance to arid conditions is crucial for restoration success (James et al., 2013; Muñoz-Rojas et al., 2014). However, restoration in semi-arid areas faces the challenge of re-establishing plant communities on altered soil substrates (Muñoz-Rojas et al., 2015). These substrates are a result of anthropogenic disturbances such as mining which have altered the plant-soil-water dynamics of the ecosystem (Machado et al., 2013). The aim of this study was to assess the impact of mining on the plant-soil-water dynamics of an arid ecosystem of Western Australia (Pilbara region, North Western Australia) and the implications these altered relationships have on seedling growth and their responses to drought. Methods Drought responses of native plant species were assessed through a series of glasshouse experiments. Firstly, 21 species dominant to the Pilbara region were subjected to drought in a topsoil growth media to assess variation in responses (leaf water potential at the time of stomatal closure) across species and identify traits associated with drought tolerance. Secondly, four species ranging in their drought tolerance identified previously, were grown to two leaf stages (second and fourth leaf stage) in three mining substrates (topsoil, a topsoil and waste mix and waste) to assess seedling drought responses to various potential restoration substrates and how that varied with plant development stage. Results and discussion Four morphological traits were found to be significantly associated with drought indicators (leaf mass ratio, stem area, stem length, stem weight), however, these were weak correlations. Waste substrate and its addition to topsoil reduced plant total biomass but did not alter species responses to drought. However, the soil physical properties of the waste reduced water retention and water availability for plant uptake resulting in seedling mortality at less negative soil water potential. Finally, no significant differences in drought tolerance were observed between the two leaf stages across the four species tested. Analysis of plant desiccation curves found the advanced leaf stage to be less tolerant of drought as shown by a decrease in soil water potential at the time of stomatal closure. Species possess a range of morphological traits, some of which are associated with drought tolerance. However, these traits on their own may not be main drivers for drought resilience and other factors play a role, for example soil nutrient availability. Materials tested in this study that may be available to create novel restoration substrates hinder plant growth but not necessarily plant responses to drought. These findings go a long way to defining some of the limitations of seedling growth and the degree of drought tolerance which will assist in the management of post-mining restoration. References James, J.J., Sheley, R.L., Erickson,T., Rollins, K.S., Taylor, M.H., Dixon, K.W. (2013) A systems approach to restoring degraded drylands. Journal of Applied Ecology 50:730-739. Machado, N. A. M., Leite, M. G. P., Figueiredo, M. A., Kozovits, A. R. (2013) Growing Ereman-thus erythropappus in crushed laterite: A promising alternative to topsoil for baux¬ite-mine revegetation. Journal of Environmental Management 129: 149-156. Muñoz-Rojas, M., Erickson, T., Merritt, D., Dixon, K. (2014) Optimising post-mining soil conditions to maximise restoration success in a biodiverse semiarid environment. Geophysical Research. Abstracts Vol. 16, EGU2014-2069-1, EGU General Assembly. Muñoz-Rojas, M., Erickson, T., Merritt, D., Dixon, K. (2015) Applying soil science for restoration of post mining degraded landscapes in semi-arid Australia: challenges and opportunities. Geophysical Research. Abstracts Vol. 17, EGU2015-3967-1, EGU General Assembly.

Impact of landform and type of land use on soils developed over granite in the monsoonal climate of North-East India

NASA Astrophysics Data System (ADS)

Prokop, Paweł; Kruczkowska, Bogusława; Jones Syiemlieh, Hiambok; Bucała, Anna

2016-04-01

Soil properties are determined by the factors such climate, organisms, topography, geology, and time. Despite human activity will be recognized as part of biotic factors or distinct from other organisms it change soil directly or indirectly by changing both soil morphology and the underlying soil-forming processes. Thus it is difficult to distinguish soil properties modified only due to human impact. A small hilly catchment (3.9 km2) at an altitude of 1750-1800 m a.s.l. was selected for the investigation of landform and land use impact on soil properties. The climate is monsoonal with 14oC of mean annual temperature and 2400 mm of mean annual rainfall. The catchment is underlain by deeply weathered (up to 20 m) granite with abundant corestones embedded in sandy grus. Soils have been classified as sandy-loam and silty-loam Ultisols. Site has relatively uniform climate and parent material, so that a large proportion of the local soil variation can be attributed to landforms and land use changes within them. Thirty soil samples from topsoil (depth up to10 cm) were analysed from two landforms: flat ridge and the middle part of 150 m length slope (15o) with three types of land use: natural deciduous forest, cultivated land (potatoes, cabbage) and 20-years old pine forest on former cultivated land. Physical (texture, bulk density) and chemical (pH, C, N, P, K, CEC) soil properties were analysed. Significant differences between the means of soil properties were identified using the t-statistics, with a level of probability of 5%. Impact of landform on topsoil properties was visible under all three land use types. Soil under natural deciduous forest on flat ridge has statistically significant less sand, higher content of C and N in comparison to soil profile localized on slope. The differences between ridge and slope under pine forest and cultivated land were limited to some chemical properties such content of C, N and CEC, while statistically significant differences in physical properties were not observed due to homogenization of topsoil during tillage. Contrasts in soil properties between three types of land use within the flat ridge were smaller than the contrast on slope. Soil under pine forest has highest pH and C, N content both within ridge (4.8, 4.24%, 0.37%) and slope (4.8, 3.46%, 0.27%) in comparison to natural deciduous forest (ridge 4.4, 3.42, 0.27%; slope 4.6, 2.32%, 0.20%) and agricultural land (ridge 4.7, 2.94%, 0.27%; slope 4.5, 2.43%, 0.23%). This indicates relatively fast recovery of topsoil chemical properties on the former cultivated land. The effects of cultivation on deep weathered granites, despite severe erosion on slopes, are less negative for environment than on surrounding areas built of quartzites with limited thickness of parent material.

Do plant-based amendments improve soil physiochemical and microbiological properties and plant growth in dryland ecosystems?

NASA Astrophysics Data System (ADS)

Kneller, Tayla; Harris, Richard; Muñoz-Rojas, Miriam

2017-04-01

Background Land intensive practices including mining have contributed to the degradation of landscapes globally. Current challenges in post-mine restoration revolve around the use of substrates poor in organic materials (e.g. overburden and waste rock) and lack of original topsoil which may result in poor seedling recruitment and in later stages in soil nutrient deficiency, metal toxicity, decreased microbial activity and high salinity (Bateman et al., 2016; Muñoz-Rojas et al., 2016). Despite continuous efforts and advances we have not proportionally advanced our capability to successfully restore these landscapes following mining. Recent attempts to improve plant establishment in arid zone restoration programs have included the application of plant based amendments to soil profiles. This approach usually aims to accelerate soil reconstruction via improvement of soil aggregate stability and increase of soil organic carbon, and water holding capacity. Whilst a significant amount of recent research has focused on the application of such amendments, studies on the potential application of plant based materials to recover soil functionality and re-establish plant communities in post-mined landscapes in arid regions are limited. Here we will discuss our work investigating the application of a plant based amendment on soil substrates commonly used in post mining restoration in the Pilbara region, Western Australia. Methodology The study was conducted in a glasshouse facility where environmental conditions were continuously monitored. Using two growth materials (topsoil and waste rock) and a plant based amendment (dry biomass of the most common grass in the Pilbara, Triodia wiseana) five different treatments were tested. Treatments consisted of control soil treatments (topsoil, waste and a mixture of the former soil types (mixture)) and two amended soil treatments (waste amended and mixture amended). Additionally, three different vegetation communities were studies, these include Triodia wiseana, Triodia wiseana and Acacia ancistrocarpa and a combination of the former species with Grevillia wickhamii. Pots were filled with soil materials and allocated plant community treatments. Plant growth and morphology, soil physiochemical (pH, electrical conductivity, N and organic C) and biological (microbial activity) properties were measured after 12 months to assess the suitability of the amendments. Results Our results have demonstrated a general decline in plant survival over the duration of 12 months, where pots with amended mine soils displaying the lowest survival rates compared to the topsoil. However, soil microbial activity of pots containing amendments was greater than those without, although there was no significant difference in microbial activity across vegetation communities (p < 0.05). References Bateman A, Lewandrowski W, Stevens JC, Muñoz-Rojas M. 2016. Ecophysiological Indicators to Assess Drought Responses of Arid Zone Native Seedlings in Reconstructed Soils. Land Degradation & Development. published online. DOI:10.1002/ldr.2660 Muñoz-Rojas M, Erickson TE, Dixon KW, Merritt DJ. 2016. Soil quality indicators to assess functionality of restored soils in degraded semiarid ecosystems. Restoration Ecology 24, 43-52. DOI: 10.1111/rec.12368

Terrestrial pyrogenic carbon export to fluvial ecosystems: Lessons learned from the White Nile watershed of East Africa

NASA Astrophysics Data System (ADS)

Güereña, David T.; Lehmann, Johannes; Walter, Todd; Enders, Akio; Neufeldt, Henry; Odiwour, Holiance; Biwott, Henry; Recha, John; Shepherd, Keith; Barrios, Edmundo; Wurster, Chris

2015-11-01

Pyrogenic carbon (PyC) is important because of its role in the global organic C (OC) cycle and in modifying soil properties. However, our understanding of PyC movement from terrestrial to fluvial ecosystems is not robust. This study examined (i) whether erosion or subsurface transport was more important for PyC export from headwaters, (ii) whether PyC was exported preferentially to total OC (TOC), and (iii) whether the movement of PyC from terrestrial to aquatic ecosystems provides an explanation for the coupling of PyC and non-PyC observed in rivers at a global scale. In the Guineo-Congolian highland forest region of western Kenya, duplicate catchments with sizes of 1-12 ha were equipped with stream gauges in primary forest and adjacent mixed agricultural landscapes that were cleared by fire 10, 16, or 62 years before. Stream water samples were taken weekly throughout 1 year and compared with runoff to assess PyC movement. Additional stream samples were taken from all major tributaries of the White Nile watershed of Lake Victoria. PyC was not found to be preferentially eroded relative to TOC or non-PyC, as topsoil (0-0.15 m) PyC concentrations (6.3 ± 0.3% of TOC; means and standard errors) were greater than runoff sediment (1.9 ± 0.4%) and dissolved PyC concentrations (2.0 ± 0.4%, n = 252). In addition, PyC proportions in eroded sediment were lower than and uncorrelated (r2 = 0.04; P = 0.14) with topsoil PyC. An enrichment of PyC was found with depth in the soil, from 6.3 ± 0.3% of TOC in the topsoil (0-0.15 m) to 12.3 ± 0.3% of TOC at 1-2 m. Base flow PyC proportions of TOC correlated well with subsoil PyC (r2 = 0.57; P < 0.05) but not with topsoil PyC (r2 = 0.18; P > 0.05). Similar PyC proportions were found in the studied headwater streams (2.7 ± 0.2%), their downstream inflow into Lake Victoria (3.7%), the other nine major rivers into Lake Victoria (4.9 ± 0.8%), and its outflow into the White Nile (1.1%). A strong positive correlation between dissolved PyC and non-PyC (r2 = 0.91; P < 0.0001) in the headwater streams reflect relationships previously seen for a range of globally important rivers, and contrasts with a negative relationship for suspended sediments (r2 = -0.5; P < 0.0001). The estimated PyC export from the Lake Victoria watershed of 11 Gg yr-1 may therefore originate to a large extent from subsoil pathways in dissolved form that appeared to be an important source of PyC in aquatic environments and may explain the coupling of PyC and non-PyC at a global scale.

Downstream mixing of sediment and tracers in agricultural catchments: Evidence of changing sediment sources and fluvial processes?

NASA Astrophysics Data System (ADS)

Ralph, Timothy; Wethered, Adam; Smith, Hugh; Heijnis, Henk

2014-05-01

Land clearance, soil tillage and grazing in agricultural catchments have liberated sediment and altered hydrological connectivity between hillslopes and channels, leading to increased sediment availability, mobilisation and delivery to rivers. The type and amount of sediment supplied to rivers is critical for fluvial geomorphology and aquatic ecosystem health. Contemporary sediment dynamics are routinely investigated using environmental radionuclides such as caesium-137 (Cs-137) and excess lead-210 (Pb-210ex), which can provide information regarding sediment source types and fluvial processes if sediment sources can be distinguished from one another and mixing models applied to representative samples. However, downstream transport, mixing and dilution of radionuclide-labelled sediment (especially from sources with low initial concentrations) can obliterate the tracer signal; sometimes before anything of geomorphological importance happens in the catchment. Can these findings be used as evidence of sediment source variations and fluvial processes when the limits of detection (of Cs-137 in particular) are being exceeded so rapidly downstream? Sediment sources and downstream sediment dynamics were investigated in Coolbaggie Creek, a major supplier of sediment to the Macquarie River in an agricultural catchment with temperate to semi-arid climate in Australia. Radionuclides were used to discriminate between the <63 micron fraction of sediment sources including forested topsoils (Cs-137 11.28 +/- 0.75 Bq/kg; Pb-210ex 181.87 +/- 20.00 Bq/kg), agricultural topsoils (Cs-137 3.21 +/- 0.26 Bq/kg; Pb-210ex 29.59 +/- 10.94 Bq/kg) and sub-soils from channel banks and gullies (Cs-137 1.45 +/- 0.47 Bq/kg; Pb-210ex 4.67 +/- 1.93 Bq/kg). Within the trunk stream, suspended sediment, organic matter and Cs-137 and Pb-210ex concentrations declined downstream. Results from a mixing model suggest that agricultural topsoils account for 95% of fine sediment entering the channel in the upper reach (<10 km long), while sub-soils account for 90 to 100% of sediment entering and being transported in the remaining ~50 km of the system. This shift in dominant sediment source material coincided with a large increase in channel cross sectional area (~20 to >200 m2) downstream, with channel expansion and gullies contributing fine sediment to the system. A lack of topsoil being supplied to the channel suggests minimal lateral connectivity between the catchment and the trunk stream in all areas apart from the upper catchment. The enlargement and entrenchment of the channel downstream has also resulted in lateral disconnection between the channel and floodplain. In this case, a rapid reduction in radionuclide concentrations downstream does coincide with hydrogeomorphic changes, supporting their use for studying short-term sediment dynamics. These findings highlight the importance of understanding hydrogeomorphic processes and connectivity when interpreting sediment source and tracer data.

How to Determine When Your Conservation Reserve Program (CRP) Pine Plantation is Ready to Thin

Treesearch

Andrew J. Londo; Timothy A. Traugott; Stephen G. Dicke; Scott D. Roberts

2002-01-01

The CRP program was initiated in 1986 by the United States Department of Agriculture, Farm Services Agency, to protect topsoil from erosion. There have been 308,000 acres of CRP pine plantations established in Mississippi, and 1.2 million acres of CRP plantations have been established nationwide. Many of the CRP pine plantations in Mississippi will soon be ready for...

Reforestation can sequester two petagrams of carbon in US topsoils in a century

Treesearch

Lucas E. Nave; Grant M. Domke; Kathryn L. Hofmeister; Umakant Mishra; Charles H. Perry; Brian F. Walters; Christopher W. Swanston

2018-01-01

Soils are Earth’s largest terrestrial carbon (C) pool, and their responsiveness to land use and management make them appealing targets for strategies to enhance C sequestration. Numerous studies have identified practices that increase soil C, but their inferences are often based on limited data extrapolated over large areas. Here, we combine 15,000 observations from...

The Topsoil Tour. The Hands-On Test Kit & Mini Curriculum for Exploring Soil.

ERIC Educational Resources Information Center

LaMotte Co., Chestertown, MD.

The goal of this mini-curriculum is for students to examine, discover, and compare the physical and chemical properties of soil. Seven units are designed to be presented as a lecture and to allow 30 to 40 students to perform every procedure, each testing their own soil sample. Games are provided in each section to reinforce the concepts presented…

Low carbon amendment rates during anaerobic soil disinfestation (ASD) at moderate soil temperatures do not decrease viability of Sclerotinia sclerotiorum sclerotia or Fusarium root rot of common bean

USDA-ARS?s Scientific Manuscript database

Anaerobic soil disinfestation (ASD; also termed biological soil disinfestation) is a non-chemical process which includes 1) soil incorporation of a labile carbon (C) source, 2) mulching with polyethylene film to limit gas exchange, and 3) drip irrigation to saturation of the topsoil or bedded area. ...

Direct monitoring of wind-induced pressure-pumping on gas transport in soil

NASA Astrophysics Data System (ADS)

Laemmel, Thomas; Mohr, Manuel; Schindler, Dirk; Schack-Kirchner, Helmer; Maier, Martin

2017-04-01

Gas exchange between soil and atmosphere is important for the biogeochemistry of soils and is commonly assumed to be governed by molecular diffusion. Yet a few previous field studies identified other gas transport processes such as wind-induced pressure-pumping to enhance soil-atmosphere fluxes significantly. However, since these wind-induced non-diffusive gas transport processes in soil often occur intermittently, the quantification of their contribution to soil gas emissions is challenging. To quantify the effects of wind-induced pressure-pumping on soil gas transport, we developed a method for in situ monitoring of soil gas transport. The method includes the use of Helium (He) as a tracer gas which was continuously injected into the soil. The resulting He steady-state concentration profile was monitored. Gas transport parameters of the soil were inversely modelled. We used our method during a field campaign in a well-aerated forest soil over three months. During periods of low wind speed, soil gas transport was modelled assuming diffusion as transport process. During periods of high wind speed, the previously steady diffusive He concentration profile showed temporary concentration decreases in the topsoil, indicating an increase of the effective gas transport rate in the topsoil up to 30%. The enhancement of effective topsoil soil gas diffusivity resulted from wind-induced air pressure fluctuations which are referred to as pressure-pumping. These air pressure fluctuations had frequencies between 0.1 and 0.01 Hz and amplitudes up to 10 Pa and occurred at above-canopy wind speeds greater than 5 m s-1. We could show the importance of the enhancement of the gas transport rate in relation with the wind intensity and corresponding air pressure fluctuations characteristics. We directly detected and quantified the pressure-pumping effect on gas transport in soil in a field study for the first time, and could thus validate and underpin the importance of this non-diffusive gas transport process. Our method can also be used to study other non-diffusive gas transport processes occurring in soil and snow, and their possible feedbacks or interactions with biogeochemical processes.

Topsoil investigation on two different urban areas in West Hungary

NASA Astrophysics Data System (ADS)

Horváth, Adrienn; Bidló, András

2015-04-01

Heavy metal contents of urban soils in two different urban areas have been investigated in Sopron town (169.01 km2) and in Szombathely town 97.50 km2) in Hungary. In a standard network 208 samples have been collected Sopron from 0 to 10 and from 10 to 20 cm depth. 164 samples have been taken on 88 points in the area of Szombathely. We analysed all of the soil samples with ICP equipment applying Lakanen-Erviö method (Ammonium Acetate - EDTA (pH 4.65)) and we focused on Co, Cu, Ni, Pb and Zn during the evaluation. The soils of suburb are determined largely by the bedrock, but in the downtown the soil pH was alkaline in soils of Sopron. Therefore, the toxic elements are still accumulated in the topsoil. The lead content was very high (suggested pollution limit >25 mg Pb/kg) in both layers on the whole area of the town. Urban soils with high copper content (among 611 mg and 1221 mg Cu/kg) have been collected from garden and viticulture areas. According to our measurements we found the highest average values in the soils of parks. The pH of urban topsoils of Szombathely was mostly neutral and it was lower in soil of agricultural areas on the suburb, where the artificial fertiliser is still used. The Pb content was high (more than 25 mg Pb/kg) in case of 13 samples next to traffic roads of the town. The Co, Cu and Ni results were below the suggested Hungarian background limits. The Zn values were above the suggested Hungarian pollution (20 mg Zn/kg) and interventional limits (>40 mg Zn/kg) in most cases. According to the results we found the highest average values of heavy metals in the soil of traffic areas or next to the Gyöngyös creek, which could be originated from traffic contamination, binding in the soil of urban green spaces, thus possibly affects human health. The research is supported by the "Agroclimate-2" (VKSZ_12-1-2013-0034) joint EU-national research project. Keywords: anthropogenic effects, heavy metal content, lead pollution, polluted urban soils

Effect of spent mushroom substrate applied to vineyard soil on the behaviour of copper-based fungicide residues.

PubMed

Herrero-Hernández, E; Andrades, M S; Rodríguez-Cruz, M S; Sánchez-Martín, M J

2011-07-01

The effect of the addition of spent mushroom substrate (SMS) to the soil as an amendment on the distribution and/or fate of copper from a copper-based fungicide applied to a vineyard soil in La Rioja (N. Spain) was studied. The study was carried out on experimental plots amended or not with SMS at rates of 40 and 100 t ha(-1). The variation in total Cu content in the topsoil (0-10 cm) and in the soil profile (0-50 cm), and the distribution of Cu in different fractions of the topsoil were studied as a function of the dose of Cu added (5 and 10 kg ha(-1)) and of the time elapsed since application (0-12 months). In addition, the changes in the chemical properties (solid organic carbon (OC), dissolved organic carbon (DOC) and pH) of the soils were studied. A greater capacity for Cu retention by the amended soils than by the unamended one was observed only when the fungicide was applied at the high dose. No effect of the amendment rate was noted on this retention capacity. The metal content in the topsoil decreased over time in step with the disappearance of the OC in the amended soil due to its oxidation, mineralization and/or leaching. This decrease in total Cu content was possibly due to the formation of soluble Cu complexes with the DOC, which facilitated its transport through the soil. A re-distribution of Cu in the different soil fractions was also observed over time, mainly from the organic to the residual fraction. The results obtained indicate that the increase in OC due to the application of SMS at the rates used does not lead to any significant increase in the persistence of Cu in the soil over time. Of greater interest would be the assessment of the risk for groundwater quality, owing to possible leaching of the fungicide enhanced by the SMS when SMS and Cu-based fungicides are jointly applied to vineyard soils. Copyright © 2011 Elsevier Ltd. All rights reserved.

Current status and temporal trend of heavy metals in farmland soil of the Yangtze River Delta Region: Field survey and meta-analysis.

PubMed

Shao, Diwei; Zhan, Yu; Zhou, Wenjun; Zhu, Lizhong

2016-12-01

While the spatial distributions of heavy metals in farmland soil of China have been comprehensively delineated, their temporal trends are rarely investigated but are important for environmental risk management. In this study, the current status and temporal trends of heavy metals in the farmland soil of Yangtze River Delta (YRD) were evaluated through field survey and meta-analysis. The field survey conducted in 2014 showed that the concentrations of Cd, Pb, Cu, Zn, and Ni in the farmland topsoil were 0.23 ± 0.14, 37.63 ± 15.60, 25.83 ± 41.62, 88.38 ± 43.30, and 29.21 ± 12.41 mg kg -1 (mean ± standard deviation), respectively. The heavy metals showed relatively higher concentrations on the borders among Zhejiang, Jiangsu, and Shanghai. In the meta-analysis, we selected 68 published studies related to heavy metal pollution in farmland topsoil of YRD from 2000 to the year (2014) when the field survey was conducted. The results show an increasing trend for Cd (p < 0.05; 0.0081 mg kg -1 year -1 ), a decreasing trend for Cu (p < 0.05; -0.80 mg kg -1 year -1 ), and no significant trend for Pb (p = 0.155), Zn (p = 0.746), and Ni (p = 0.305). The increasing rate of Cd from the meta-analysis is consistent with the rate (0.0013 mg kg -1 year -1 ) derived from the mass balance calculation for Cd, where atmospheric deposition originated from intensive coal combustion is considered as the main source of Cd in the topsoil. The decreasing trend of Cu is likely due to largely reduced application of copper-based agrochemicals. Environmental regulation and soil remediation are needed to protect food safety and ecosystem from heavy metal pollution, especially Cd. Copyright © 2016 Elsevier Ltd. All rights reserved.

Modeling Soil Organic Carbon at Regional Scale by Combining Multi-Spectral Images with Laboratory Spectra.

PubMed

Peng, Yi; Xiong, Xiong; Adhikari, Kabindra; Knadel, Maria; Grunwald, Sabine; Greve, Mogens Humlekrog

2015-01-01

There is a great challenge in combining soil proximal spectra and remote sensing spectra to improve the accuracy of soil organic carbon (SOC) models. This is primarily because mixing of spectral data from different sources and technologies to improve soil models is still in its infancy. The first objective of this study was to integrate information of SOC derived from visible near-infrared reflectance (Vis-NIR) spectra in the laboratory with remote sensing (RS) images to improve predictions of topsoil SOC in the Skjern river catchment, Denmark. The second objective was to improve SOC prediction results by separately modeling uplands and wetlands. A total of 328 topsoil samples were collected and analyzed for SOC. Satellite Pour l'Observation de la Terre (SPOT5), Landsat Data Continuity Mission (Landsat 8) images, laboratory Vis-NIR and other ancillary environmental data including terrain parameters and soil maps were compiled to predict topsoil SOC using Cubist regression and Bayesian kriging. The results showed that the model developed from RS data, ancillary environmental data and laboratory spectral data yielded a lower root mean square error (RMSE) (2.8%) and higher R2 (0.59) than the model developed from only RS data and ancillary environmental data (RMSE: 3.6%, R2: 0.46). Plant-available water (PAW) was the most important predictor for all the models because of its close relationship with soil organic matter content. Moreover, vegetation indices, such as the Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI), were very important predictors in SOC spatial models. Furthermore, the 'upland model' was able to more accurately predict SOC compared with the 'upland & wetland model'. However, the separately calibrated 'upland and wetland model' did not improve the prediction accuracy for wetland sites, since it was not possible to adequately discriminate the vegetation in the RS summer images. We conclude that laboratory Vis-NIR spectroscopy adds critical information that significantly improves the prediction accuracy of SOC compared to using RS data alone. We recommend the incorporation of laboratory spectra with RS data and other environmental data to improve soil spatial modeling and digital soil mapping (DSM).

Signatures of chlorinated dioxins and furans along the exposure path - The relation between vegetation and soil.

PubMed

Hangen, Edzard; Gonser, Stefan; Köhler, Jutta

2018-08-01

Polychlorinated dibenzo-p-dioxins and dibenzo-furans (PCDD/Fs) belong to the most toxic persistent organic environmental pollutants. Therefore, knowledge about their fate along the exposure path is of special concern. In order to comprehend the transfer of PCDD/Fs across different environmental compartments, PCDD/F concentrations in plants and in soil were evaluated. Pairs of soil and plant samples were selected according to the shortest distance between sampling points. At 15 sites PCDD/F concentrations in spruce needles and in forest humus layers where compared. Summer conditions were evaluated on the basis of 8 sites with ryegrass- and grassland topsoil samples. Autumn conditions were addressed using 7 sites with curly kale and topsoil samples under grassland. Correlation analyses of the PCDD/F congener profiles for plant- and soil samples were conducted. The correlations were compared to influencing site (e.g. local temperature) and spatial as well as temporal offset parameters. No governing parameter that decisively influenced the similarity between plant and soil signature became evident. By means of the toxicity factors of TEQ-WHO, tetra- and penta-PCDD/F homologues were assigned to the group of low-chlorinated homologues (lcH), and hexa-, hepta- and octa-PCDD/F homologues to the high-chlorinated homologues (hcH). lcH and hcH are presumed to differ in solubility, volatility and rate of degradation. The ratio of lcH/hcH revealed characteristic fingerprints that enabled the differentiation of the individual PCDD/F-plant and -soil pairs. Spruce-humus pairs showed a close relation during winter exposure times, while the lower summer concentrations were not reflected in the humus layer. Kale was exposed at the beginning of the season with elevated PCDD/F immissions, and showed a closer relation to grassland topsoil than did ryegrass. lcH/hcH proved as a simple criterion that can reveal related PCDD/F fingerprints of different environmental compartments despite signal attenuation due to decomposition, volatilization and particulate transport. Copyright © 2018 Elsevier B.V. All rights reserved.

Soil Carbon 4 per mille

NASA Astrophysics Data System (ADS)

Minasny, Budiman; van Wesemael, Bas

2017-04-01

The '4 per mille Soils for Food Security and Climate' was launched at the COP21 aiming to increase global soil organic matter stocks by 4 per mille (or 0.4 %) per year as a compensation for the global emissions of greenhouse gases by anthropogenic sources. This paper surveyed the soil organic carbon (SOC) stock estimates and sequestration potentials from 20 regions in the world (New Zealand, Chile, South Africa, Australia, Tanzania, Indonesia, Kenya, Nigeria, India, China Taiwan, South Korea, China Mainland, United States of America, France, Canada, Belgium, England & Wales, Ireland, Scotland, and Russia) and asked whether the 4 per mille initiative is feasible. This study highlights region specific efforts and scopes for soil carbon sequestration. Reported soil C sequestration rates generally show that under best management practices, 4 per mille or even higher sequestration rates can be accomplished. High C sequestration rates (up to 10 per mille) can be achieved for soils with low initial SOC stock (topsoil less than 30 t C ha-1), and at the first twenty years after implementation of best management practices. In addition, areas that have reached equilibrium but not at their saturation level will not be able to further increase their sequestration. We found that most studies on SOC sequestration globally only consider topsoil (up to 0.3 m depth), as it is considered to be most affected by management techniques. The 4 per mille initiative was based on a blanket calculation of the whole global soil profile C stock, however the potential to increase SOC is mostly on managed agricultural lands. If we consider 4 per mille on global topsoil of agricultural land, SOC sequestration is about 3.6 Gt C per year, which effectively offset 40% of global anthropogenic greenhouse gas emissions. As a strategy for climate change mitigation, soil carbon sequestration buys time over the next ten to twenty years while other effective sequestration and low carbon technologies become viable. The challenge for cropping farmers is to find disruptive technologies that will further improve soil condition and deliver increased soil carbon. Progress in 4 per mille requires collaboration and communication between scientists, farmers, policy makers, and marketeers.

Organic complexation and translocation of ferric iron in podzols of the Negro River watershed. Separation of secondary Fe species from Al species

NASA Astrophysics Data System (ADS)

Fritsch, E.; Allard, Th.; Benedetti, M. F.; Bardy, M.; do Nascimento, N. R.; Li, Y.; Calas, G.

2009-04-01

The development of podzols in lateritic landscapes of the upper Amazon basin contributes to the exportation of organic carbon and associated metals in the black waters of the Negro River watershed. We have investigated the distribution of Fe III in the clay-size fraction of eight organic-rich horizons of waterlogged plateau podzols, to unravel the weathering conditions and mechanisms that control its transfer to the rivers. The speciation and amount of Fe III stored in residual mineral phases of laterites, or bound to organic compounds of weakly and well-expressed podzols, were determined by electron paramagnetic resonance spectroscopy combined with chemical analyses. Reducing conditions restrict the production of organo-Fe complexes in the subsoil B-horizons of waterlogged podzols and most of the Fe 2+ released from the dissolution of Fe-oxides is exported to the rivers via the perched groundwater. However, significant amounts of diluted Fe III bound to organic ligands (Fe IIIOM) and nano Fe-oxides are produced at the margin of the depression in the topsoil A horizons of weakly expressed podzols due to shorter periods of anoxia. The downward translocation of organically bound metals from topsoil A to subsoil B-horizons of podzols occurs in shorter distances for Fe than it does for Al. This separation of secondary Fe species from Al species is attributed to the physical fractionation of their organic carriers in texture contrasted B-horizons of podzols, as well as to the effect of pH on metal speciation in soil solutions and metal binding onto soil organic ligands (mostly for Al). This leads us to consider the topsoil A horizons of weakly expressed podzols, as well as the subsoil Bh horizon of better-expressed ones, as the main sources for the transfer of Fe IIIOM to the rivers. The concentration of Fe IIIOM rises from soil sources to river colloids, suggesting drastic biogeochemical changes in more oxygenated black waters of the Negro River watershed. The contribution of soil organic matter to the transfer of Fe to rivers is likely at the origin of the peculiar Fe isotope pattern recently recognized in podzolic environments.

Engineering Biochar Hydrophobicity to Mitigate Risk of Top-Soil Erosion

NASA Astrophysics Data System (ADS)

Kinney, T. J.; Dean, M. R.; Hockaday, W. C.; Masiello, C. A.

2009-12-01

The pyrolysis of biomass is a net carbon negative method of sequestering atmospheric carbon as recalcitrant black carbon. The resulting solid product, called biochar, is likely to improve agricultural soils when used as a soil conditioner in sustainable land management practice. Biochar has been shown to improve crop yields, improve water-holding capacity in sandy soils, increase cation exchange capacity (CEC), and retain nutrients from fertilization longer than soils unamended with biochar. Biochar undoubtedly has high potential as both a carbon management tool and a tool to increase global food production. However, little is understood about possible side effects of biochar in agricultural soils such as ecosystem toxicity, interactions with biota, and modification of soil hydrologic properties, such as permeability. The hydrophobicity of a soil determines how easily precipitation can permeate soil pores. Water that fails to permeate is redirected as runoff, responsible for the detachment and transport of nutrient-rich topsoil particles. Mitigating top-soil erosion is an important aspect of sustainable land management. Biochar, primarily composed of condensed aromatic structures, is a hydrophobic material and incorporating it into agricultural soils may act to alter soil hydrology through multiple avenues. These include a likely increase in soil water-holding capacity (a positive outcome) and a potential increase in soil hydrophobicity (a negative outcome). In an effort to understand how to engineer reduced biochar hydrophobicity, we investigated the hydrophobicity of biochars as a function of biomass feedstock, pyrolysis temperatures, and post-pyrolysis chemical treatments. We used Water Drop Penetration Time (WDPT) and Molarity of an Ethanol Drop (MED) tests to measure hydrophobicity, and FTIR, CPMAS-NMR, and N2-BET to probe the surface chemistry, bulk chemistry, and surface area of various biochars, respectively. We used post-pyrolysis chemical treatments of biochar to study the origin of biochar hydrophobicity and to assess the possibility of reducing hydrophobicity prior to soil amendment. We used correlative analysis to study the relationship between hydrophobicity, biomass and pyrolysis characteristics, as well as chemical treatments. Future work will focus on engineering designer biochars which minimize hydrophobicity while maximizing positive benefits, such as ion exchange capacity.

Modeling Soil Organic Carbon at Regional Scale by Combining Multi-Spectral Images with Laboratory Spectra

PubMed Central

Peng, Yi; Xiong, Xiong; Adhikari, Kabindra; Knadel, Maria; Grunwald, Sabine; Greve, Mogens Humlekrog

2015-01-01

There is a great challenge in combining soil proximal spectra and remote sensing spectra to improve the accuracy of soil organic carbon (SOC) models. This is primarily because mixing of spectral data from different sources and technologies to improve soil models is still in its infancy. The first objective of this study was to integrate information of SOC derived from visible near-infrared reflectance (Vis-NIR) spectra in the laboratory with remote sensing (RS) images to improve predictions of topsoil SOC in the Skjern river catchment, Denmark. The second objective was to improve SOC prediction results by separately modeling uplands and wetlands. A total of 328 topsoil samples were collected and analyzed for SOC. Satellite Pour l’Observation de la Terre (SPOT5), Landsat Data Continuity Mission (Landsat 8) images, laboratory Vis-NIR and other ancillary environmental data including terrain parameters and soil maps were compiled to predict topsoil SOC using Cubist regression and Bayesian kriging. The results showed that the model developed from RS data, ancillary environmental data and laboratory spectral data yielded a lower root mean square error (RMSE) (2.8%) and higher R2 (0.59) than the model developed from only RS data and ancillary environmental data (RMSE: 3.6%, R2: 0.46). Plant-available water (PAW) was the most important predictor for all the models because of its close relationship with soil organic matter content. Moreover, vegetation indices, such as the Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI), were very important predictors in SOC spatial models. Furthermore, the ‘upland model’ was able to more accurately predict SOC compared with the ‘upland & wetland model’. However, the separately calibrated ‘upland and wetland model’ did not improve the prediction accuracy for wetland sites, since it was not possible to adequately discriminate the vegetation in the RS summer images. We conclude that laboratory Vis-NIR spectroscopy adds critical information that significantly improves the prediction accuracy of SOC compared to using RS data alone. We recommend the incorporation of laboratory spectra with RS data and other environmental data to improve soil spatial modeling and digital soil mapping (DSM). PMID:26555071

Monitoring the performance of an alternative cover using caisson lysimeters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Waugh, W.J.; Smith, G.M.; Mushovic, P.S.

2004-02-29

The U.S. Department of Energy (DOE) office in Grand Junction, Colorado, and the U.S. Environmental Protection Agency (EPA), Region 8, collaborated on a series of field lysimeter studies to design and monitor the performance of an alternative cover for a uranium mill tailings disposal cell at the Monticello, Utah, Superfund Site. Because groundwater recharge is naturally limited at Monticello in areas with thick loess soils, DOE and EPA chose to design a cover for Monticello using local soils and a native plant community to mimic this natural soilwater balance. Two large drainage lysimeters fabricated of corrugated steel culvert lined withmore » high-density polyethylene were installed to evaluate the hydrological and ecological performance of an alternative cover design constructed in 2000 on the disposal cell. Unlike conventional, lowpermeability designs, this cover relies on (1) the water storage capacity of a 163-cm soil “sponge” layer overlying a sand-and-gravel capillary barrier to retain precipitation while plants are dormant and (2) native vegetation to remove precipitation during the growing season. The sponge layer consists of a clay loam subsoil compacted to 1.65 g/cm2 in one lysimeter and a loam topsoil compacted to 1.45 g/cm2 in the other lysimeter, representing the range of as-built conditions constructed in the nearby disposal cell cover. About 0.1 mm of drainage occurred in both lysimeters during an average precipitation year and before they were planted, an amount well below the EPA target of <3.0 mm/yr. However, the cover with less compacted loam topsoil sponge had a 40% greater water storage capacity than the cover with overly compacted clay loam subsoil sponge. The difference is attributable in part to higher green leaf area and water extraction by plants in the loam topsoil. The lesson learned is that seemingly subtle differences in soil types, sources, and compaction can result in salient differences in performance. Diverse, seeded communities of predominantly native perennial species were established on both lysimeters during an extended 3-yr drought, highlighting the importance of a sound understanding of the local ecology and of implementing the science and methods of disturbed-land revegetation.« less

Microbiomes structure and diversity in different horizons of full soil profiles

NASA Astrophysics Data System (ADS)

Chernov, Timofey; Tkhakakhova, Azida; Zhelezova, Alena; Semenov, Mikhail; Kutovaya, Olga

2017-04-01

Topsoil is a most common object for soil metagenomic studies; sometimes soil profile is being formally split in layers by depth. However, Russian Soil Science School formulated the idea of soil profile as a complex of soil horizons, which can differ in their properties and genesis. In this research we analyzed 57 genetic soil horizons of 8 different soils from European part of Russia: Albeluvisol, Greyzemic Phaeozem, three Chermozems (different land use - till, fallow, wind-protecting tree line), Rhodic Cambisol, Haplic Kastanozem and Salic Solonetz (WRB classification). Sampling was performed from all genetic horizons in each soil profile starting from topsoil until subsoil. Total DNA was extracted and 16S rRNA sequencing was provided together with chemical analysis of soil (pH measurement, C and N contents, etc.). Structure and diversity of prokaryotic community are significantly different in those soil horizons, which chemical properties and processes of origin are contrasting with nearest horizons: Na-enriched horizon of Solonetz, eluvial horizon of Albeluvisol, plough pan of Agrochernozem. Actinobacteria were abundant in top horizons of soils in warm and dry climate, while Acidobacteria had the highest frequency in soils of moist and cold regions. Concerning Archaea, Thaumarchaeota prevailed in all studied soils. Their rate was higher in microbiomes of upper horizons of steppe soils and it was reducing with depth down the profile. Prokaryotic communities in Chernozems were clustered by soil horizons types: microbiomes of A (organic topsoil) and B (mineral) horizons formed non-overlapping clusters by principal component analysis, cluster formed by prokaryotic communities of transitional soil horizons (AB) take place between clusters of A and B horizons. Moreover, prokaryotic communities of A horizons differ from each other strongly, while microbiomes of B horizons formed a narrow small cluster. It must be explaned by more diverse conditions in upper A horizons. Thus, ecological differences between soil horizons are important factor of differentiation of prokaryotic communities in soil profile; their structure can be specific for horizon type. This study was supported by Russian Science Foundation, project no. 14-26-00079

Enhancement of Plant Establishment on Dredged Material Sites with Mycorrhizal Fungi and Clay Amendments

DTIC Science & Technology

1989-10-01

montmorillonite enhanced the growth of smooth brome grass. Topsoil, the clays attapulgite and kaolinite , and the commercial products Agrosoke anj Stawetwere...clays bentonite, attapulgite, kaolinite , and montmorillonite . Trade name and company addresses for the clays are listed in Table 1. Agrosoke and Stawet...desertcoZa, G. etunicatwn, and G. intraradice8. The clays attapulgite, ben- tonite, kaclinite,/and montmorillonite from various commercial sources were

Influence of subsoil and Soil Volume on the accumulation of nickel by Alyssum corsicum grown on a serpentine soil

USDA-ARS?s Scientific Manuscript database

Aims: Test the effect of soil volume and presence of subsoil on Ni hyperaccumulation. Methods: A. corsicum Duby was grown for 3 months on Chrome loam topsoil and subsoil from near Reistertown, MD, in a test of growth and Ni accumulation with varied soil masses (2.8 and 5.6 kg pot-1) to study the im...

Science You Can Use Bulletin: From watersheds to the web: Online tools for modeling forest soil erosion

Treesearch

Sue Miller; Bill Elliot; Pete Robichaud; Randy Foltz; Dennis Flanagan; Erin Brooks

2014-01-01

Forest erosion can lead to topsoil loss, and also to damaging deposits of sediment in aquatic ecosystems. For this reason, forest managers must be able to estimate the erosion potential of both planned management activities and catastrophic events, in order to decide where to use limited funds to focus erosion control efforts. To meet this need, scientists from RMRS (...

Chapter 3: Selecting materials for mine soil construction when establishing forests on Appalachian mined lands

Treesearch

Jeff Skousen; Carl Zipper; Jim Burger; Christopher Barton; Patrick. Angel

2017-01-01

The Forestry Reclamation Approach (FRA), a method for reclaiming coal-mined land to forest (Chapter 2, this volume), is based on research, knowledge, and experience of forest soil scientists and reclamation practitioners. Step 1 of the FRA is to create a suitable rooting medium for good tree growth that is no less than 4 feet deep and consists of topsoil, weathered...

HCHs and DDTs in Soils around Guanting Reservoir in Beijing, China: Spatial-Temporal Variation and Countermeasures

PubMed Central

Wang, Tie-yu; Tan, Bing; Lu, Yong-long

2012-01-01

The concentrations of hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs) in the topsoil samples around the Guanting Reservoir in Beijing were measured, and their spatial distribution and environmental risks were analyzed by GIS. The results showed that in 2003, 2007, and 2009, the HCHs concentrations were 0.66, 0.85, and 0.73 ng/g, and the DDTs concentrations were 9.50, 7.80, and 6.46 ng/g in the studied area, respectively. In the topsoil, the HCHs concentrations did not change much while the DDTs concentrations declined steadily. Most of the current residues in soil come from the POPs used in the past years but some new input is also detected in certain regions. The level of HCHs and DDTs residues in the south reservoir is lower than that in the north reservoir. The middle region has the highest HCHs and DDTs concentrations, especially near the Beixinpu town. The high risk regions of pollution of HCHs and DDTs are mainly distributed in the vicinity of Beixinpu town as well. Based on the aforementioned results, a comprehensive countermeasure is proposed entailing decision making, local implementation, scientific support, and public participation with regard to the long-term control and management of POPs around the Guanting Reservoir. PMID:23346019

Reduction in soil aggregation in response to dust emission processes

NASA Astrophysics Data System (ADS)

Swet, Nitzan; Katra, Itzhak

2016-09-01

Dust emission by aeolian (wind) soil erosion depends on the topsoil properties of the source area, especially on the nature of the aggregates where most dust particles are held. Although the key role of soil aggregates in dust emission, the response of soil aggregation to aeolian processes and its implications for dust emission remain unknown. This study focuses on aggregate size distribution (ASD) analyses before and after in-situ aeolian experiments in semiarid loess soils that are associated with dust emission. Wind tunnel simulations show that particulate matter (PM) emission and saltation rates depend on the initial ASD and shear velocity. Under all initial ASD conditions, the content of saltator-sized aggregates (63-250 μm) increased by 10-34% due to erosion of macro-aggregates (> 500 μm), resulting in a higher size ratio (SR) between the saltators and macro-aggregates following the aeolian erosion. The results revealed that the saltator production increases significantly for soils that are subjected to short-term (anthropogenic) disturbance of the topsoil. The findings highlight a decrease in soil aggregation for all initial ASD's in response to aeolian erosion, and consequently its influence on the dust emission potential. Changes in ASD should be considered as a key parameter in dust emission models of complex surfaces.

Estimating spatially distributed soil texture using time series of thermal remote sensing - a case study in central Europe

NASA Astrophysics Data System (ADS)

Müller, Benjamin; Bernhardt, Matthias; Jackisch, Conrad; Schulz, Karsten

2016-09-01

For understanding water and solute transport processes, knowledge about the respective hydraulic properties is necessary. Commonly, hydraulic parameters are estimated via pedo-transfer functions using soil texture data to avoid cost-intensive measurements of hydraulic parameters in the laboratory. Therefore, current soil texture information is only available at a coarse spatial resolution of 250 to 1000 m. Here, a method is presented to derive high-resolution (15 m) spatial topsoil texture patterns for the meso-scale Attert catchment (Luxembourg, 288 km2) from 28 images of ASTER (advanced spaceborne thermal emission and reflection radiometer) thermal remote sensing. A principle component analysis of the images reveals the most dominant thermal patterns (principle components, PCs) that are related to 212 fractional soil texture samples. Within a multiple linear regression framework, distributed soil texture information is estimated and related uncertainties are assessed. An overall root mean squared error (RMSE) of 12.7 percentage points (pp) lies well within and even below the range of recent studies on soil texture estimation, while requiring sparser sample setups and a less diverse set of basic spatial input. This approach will improve the generation of spatially distributed topsoil maps, particularly for hydrologic modeling purposes, and will expand the usage of thermal remote sensing products.

Organic matter losses in German Alps forest soils since the 1970s most likely caused by warming

NASA Astrophysics Data System (ADS)

Prietzel, Jörg; Zimmermann, Lothar; Schubert, Alfred; Christophel, Dominik

2016-07-01

Climate warming is expected to induce soil organic carbon losses in mountain soils that result, in turn, in reduced soil fertility, reduced water storage capacity and positive feedback on climate change. Here we combine two independent sets of measurements of soil organic carbon from forest soils in the German Alps--repeated measurements from 1976 to 2010 and from 1987 to 2011--to show that warming has caused a 14% decline in topsoil organic carbon stocks. The decreases in soil carbon occurred over a period of significant increases in six-month summer temperatures, with the most substantial decreases occurring at sites with large changes in mean annual temperature. Organic carbon stock decreases were largest--on average 32%--in forest soils with initial topsoil organic carbon stocks greater than 8 kg C m-2, which can be found predominantly on calcareous bedrock. However, organic carbon stocks of forest soils with lower initial carbon stocks, as well as soils under pasture or at elevations above 1,150 m, have not changed significantly. We conclude that warming is the most likely reason for the observed losses of soil organic carbon, but that site, land use and elevation may ameliorate the effects of climate change.

Intrinsic vulnerability assessment of shallow aquifers of the sedimentary basin of southwestern Nigeria

PubMed Central

2018-01-01

The shallow groundwater of the multi-layered sedimentary basin aquifer of southwestern Nigeria was assessed based on its intrinsic vulnerability property. The vulnerability evaluation involves determining the protective cover and infiltration condition of the unsaturated zone in the basin. This was achieved using the PI (P stands for protective cover effectiveness of the overlying lithology and I indicates the degree of infiltration bypass) vulnerability method of the European vulnerability approach. The PI method specifically measures the protection cover and the degree to which the protective cover is bypassed. Intrinsic parameters assessed were the subsoil, lithology, topsoil, recharge and fracturing for the protective cover. The saturated hydraulic conductivity of topsoil, infiltration processes and the lateral surface and subsurface flow were evaluated for the infiltration bypassed. The results show moderate to very low vulnerability areas. Low vulnerability areas were characterised by lithology with massive sandstone and limestone, subsoils of sandy loam texture, high slopes and high depth to water table. The moderate vulnerability areas were characterised by high rainfall and high recharge, low water table, unconsolidated sandstones and alluvium lithology. The intrinsic vulnerability properties shown in vulnerability maps will be a useful tool in planning and monitoring land use activities that can be of impact in groundwater pollution.

Precipitation overrides warming in mediating soil nitrogen pools in an alpine grassland ecosystem on the Tibetan Plateau.

PubMed

Lin, Li; Zhu, Biao; Chen, Chengrong; Zhang, Zhenhua; Wang, Qi-Bing; He, Jin-Sheng

2016-08-16

Soils in the alpine grassland store a large amount of nitrogen (N) due to slow decomposition. However, the decomposition could be affected by climate change, which has profound impacts on soil N cycling. We investigated the changes of soil total N and five labile N stocks in the topsoil, the subsoil and the entire soil profile in response to three years of experimental warming and altered precipitation in a Tibetan alpine grassland. We found that warming significantly increased soil nitrate N stock and decreased microbial biomass N (MBN) stock. Increased precipitation reduced nitrate N, dissolved organic N and amino acid N stocks, but increased MBN stock in the topsoil. No change in soil total N was detected under warming and altered precipitation regimes. Redundancy analysis further revealed that soil moisture (26.3%) overrode soil temperature (10.4%) in explaining the variations of soil N stocks across the treatments. Our results suggest that precipitation exerted stronger influence than warming on soil N pools in this mesic and high-elevation grassland ecosystem. This indicates that the projected rise in future precipitation may lead to a significant loss of dissolved soil N pools by stimulating the biogeochemical processes in this alpine grassland.

Cause-Effect Relations with Regard to Functional and Morphological Humus Characteristics in Mixed Forest Stands

NASA Astrophysics Data System (ADS)

Schua, K.; Feger, K.-H.; Wagner, S.; Eisenhauer, D.-R.; Raben, G.

2009-04-01

A major argument brought forward when giving reasons for the admixture of deciduous tree species into coniferous forest stands is the amelioration and stabilization of biogeochemical cycles. An ecologically oriented silviculture relies on detailed knowledge about the ecosystem effects of practical measures. Thus, it focuses on the ‘amelioration potential' of a specific tree species with respect to changes of topsoil characteristics in typical monocultural situations. Up-to-now, few data is available concerning the percentages of deciduous species (degree of admixture) or type of admixture (single-tree, small or large groups) required to achieve desired effects, e.g. faster decomposition and incorporation of organic matter in the mineral soil. Thus, the objective of this study is (1) to analyze the impact of admixtures on topsoil properties and processes, and (2) to establish spatial models of such effects. The experiments are conducted in even-aged Norway spruce (Picea abies [L.] KARST.) stands with a variable admixture of Silver birch (Betula pendula Roth) in the Ore Mountains (Saxony, SE Germany). The approach starts with explanation of single-tree-effects and approves in a next step the enlargement to forest stand ("from-point-to-area-approach"). This attempt is expected to provide models with few parameters which can be used to modify the common exclusive growth models.

Small-scale spatial heterogeneity of ecosystem properties, microbial community composition and microbial activities in a temperate mountain forest soil.

PubMed

Štursová, Martina; Bárta, Jiří; Šantrůčková, Hana; Baldrian, Petr

2016-12-01

Forests are recognised as spatially heterogeneous ecosystems. However, knowledge of the small-scale spatial variation in microbial abundance, community composition and activity is limited. Here, we aimed to describe the heterogeneity of environmental properties, namely vegetation, soil chemical composition, fungal and bacterial abundance and community composition, and enzymatic activity, in the topsoil in a small area (36 m 2 ) of a highly heterogeneous regenerating temperate natural forest, and to explore the relationships among these variables. The results demonstrated a high level of spatial heterogeneity in all properties and revealed differences between litter and soil. Fungal communities had substantially higher beta-diversity than bacterial communities, which were more uniform and less spatially autocorrelated. In litter, fungal communities were affected by vegetation and appeared to be more involved in decomposition. In the soil, chemical composition affected both microbial abundance and the rates of decomposition, whereas the effect of vegetation was small. Importantly, decomposition appeared to be concentrated in hotspots with increased activity of multiple enzymes. Overall, forest topsoil should be considered a spatially heterogeneous environment in which the mean estimates of ecosystem-level processes and microbial community composition may confound the existence of highly specific microenvironments. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

The forgotten part of carbon cycling: Organic matter storage and turnover in subsoils [SUBSOM

NASA Astrophysics Data System (ADS)

Marschner, B.

2013-12-01

In the past, carbon flux measurements and modelling have mostly considered the topsoil where C-concentrations, root densities and microbial activities are generally highest. However, depending on climate zone and land use, this soil compartment contains only 30-50% of the C-stocks of the first meter. If the deeper subsoil down to 3 m is also considered, the contribution of topsoil carbon stocks to total soil C-pools is only 20-40%. Another distinct property of subsoil organic matter is its high apparent 14C age. The 14C age of bulk soil organic matter below 30 cm depth generally increases continuously indicating mean residence times of several 103 to 104 years. Large pool size and high radiocarbon age suggest that subsoil OM has accumulated at very low rates over very long time periods and therefore appears to be very stable. In a review, several hypotheses for explaining why subsoil SOM is so seemingly old and inert are presented. Then a recently granted German research unit consisting of 9 subprojects from all soil science disciplines is introduced, which addresses these questions using field measurements of C-fluxes, 14C analyses and conducting field and lab experiments. 40-60% of soil C-pools are found below 40 cm depth (Data from Jobbagy & Jackson 2000).

Soil dioxins levels at agriculture sites and natural preserve areas of Taiwan.

PubMed

Jou, Jin-juh; Lin, Kae-Long; Chung, Jen-Chir; Liaw, Shu-Liang

2007-08-17

In this study, agriculture soil in Taiwan has been sampled and analyzed to determine the background level of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/DF) in the agricultural and nature preserve areas. Another objective is to investigate relationship between soil characteristics and air deposition in Taiwan. The results indicate that in nature preserve areas the topsoil shows an extraordinary profile of PCDD/DF compared to that in the air deposition. The PCDD/DF levels of the low-contaminated agricultural soils are compatible with those of the nature preserves soils. However, in the highly-contaminated agricultural soils, there is an abrupt jump in their concentrations, 10-100 times higher. The overall I-TEQ values of the background topsoils range from 0.101 to 15.2 ng I-TEQ/kg. Near industrial/urban areas in Taiwan the PCDD/DF are slightly higher compared to those in the low concentration group. Typically, the PCDD/DF background values found in this survey fall in the 90% confidence interval and can thus, be deemed the background levels in Taiwan. Ninety-five percent of these data are below the European and American soil standard of 10 ng I-TEQ/kg d.w. The PCDD/DF profile with one neighborhood soil sample was shown no significant difference.

Succession on regraded placer mine spoil in Alaska, USA, in relation to initial site characteristics

USGS Publications Warehouse

Densmore, R.V.

1994-01-01

This study evaluated the rate and pattern of natural succession on regraded placer mine spoil in relation to initial substrate characteristics. The study site was the Glen Creek watershed of the Kantishna mining area of Denali National Park and Preserve, Alaska. After regrading, twelve 0.01-ha plots were established and substrate characteristics were measured. Natural plant succession was evaluated after five growing seasons. Three successional patterns were identified on the basis of plant community characteristics using cluster analysis, and were related to substrate characteristics. First, a riparian plant community with vigorous Salix alaxensis and Alnus crispa grew rapidly on topsoil that had been spread over the regraded spoil. Second, a similar plant community with less vigorous S. alaxensis developed more slowly on unprocessed spoil and spoil amended with a small amount of topsoil. Third, processed spoil remained almost bare of vegetation, although S. alaxensis was able to establish and persist in a stunted growth form. In contrast, Alnus crispa had difficulty establishing on processed spoil, but the few established seedlings grew well. Several substrate variables, including the proportion of silt and clay vs. sand, total nitrogen, and water retention capacity, were good predictors of the rate and pattern of succession. Total nitrogen was the best single predictor for the number of vigorous S. alaxensis.

Installation restoration research program: Assessment of geophysical methods for subsurface geologic mapping, cluster 13, Edgewood Area, Aberdeen Proving Ground, Maryland. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Butler, D.K.; Sharp, M.K.; Sjostrom, K.J.

1996-10-01

Seismic refraction, electrical resistivity, and transient electromagnetic surveys were conducted at a portion of Cluster 13, Edgewood Area of Aberdeen Proving Ground, Maryland. Seismic refraction cross sections map the topsoil layer and the water table (saturated zone). The water table elevations from the seismic surveys correlate closely with water table elevations in nearby monitoring wells. Electrical resistivity cross sections reveal a very complicated distribution of sandy and clayey facies in the upper 10 - 15 m of the subsurface. A continuous surficial (topsoil) layer correlates with the surficial layer of the seismic section and nearby boring logs. The complexity andmore » details of the electrical resistivity cross section correlate well with boring and geophysical logs from nearby wells. The transient electromagnetic surveys map the Pleistocene-Cretaceous boundary, the saprolite, and the top of the Precambrian crystalline rocks. Conducting the transient electromagnetic surveys on a grid pattern allows the construction of a three-dimensional representation of subsurface geology (as represented by variations of electrical resistivity). Thickness and depth of the saprolitic layer and depth to top of the Precambrian rocks are consistent with generalized geologic cross sections for the Edgewood Area and depths projected from reported depths at the Aberdeen Proving Ground NW boundary using regional dips.« less

Assessment of lead pollution in topsoils of a southern Italy area: Analysis of urban and peri-urban environment.

PubMed

Guagliardi, Ilaria; Cicchella, Domenico; De Rosa, Rosanna; Buttafuoco, Gabriele

2015-07-01

Exposure to lead (Pb) may affect adversely human health. Mapping soil Pb contents is essential to obtain a quantitative estimate of potential risk of Pb contamination. The main aim of this paper was to determine the soil Pb concentrations in the urban and peri-urban area of Cosenza-Rende to map their spatial distribution and assess the probability that soil Pb concentration exceeds a critical threshold that might cause concern for human health. Samples were collected at 149 locations from residual and non-residual topsoil in gardens, parks, flower-beds, and agricultural fields. Fine earth fraction of soil samples was analyzed by X-ray Fluorescence spectrometry. Stochastic images generated by the sequential Gaussian simulation were jointly combined to calculate the probability of exceeding the critical threshold that could be used to delineate the potentially risky areas. Results showed areas in which Pb concentration values were higher to the Italian regulatory values. These polluted areas were quite large and likely, they could create a significant health risk for human beings and vegetation in the near future. The results demonstrated that the proposed approach can be used to study soil contamination to produce geochemical maps, and identify hot-spot areas for soil Pb concentration. Copyright © 2015. Published by Elsevier B.V.

[Soil seed bank research of China mining areas: necessity and challenges].

PubMed

Chang, Qing; Zhang, Da-Wei; Li, Xue; Peng, Jian; Guan, Ai-Nong; Liu, Xiao-Si

2011-05-01

Soil seed bank consists of all living seeds existed in soil and its surface litter, especially in topsoil, and can reflect the characteristics of regional biodiversity. As the base of vegetation restoration and potential greening material, topsoil and its seed bank are the limited and non-renewable resources in mining areas. The study of soil seed bank has become one of the hotspots in the research field of vegetation restoration and land reclamation in China mining areas. Owing to the special characteristics of mining industry, the soil seed bank study of mining areas should not only concern with the seed species, quantities, and their relations with ground surface vegetation, but also make use of the research results on the soil seed bank of other fragile habitats. Besides, a breakthrough should be sought in the thinking ways and research approach. This paper analyzed the particularity of mining area's soil seek bank research, summarized the research progress in the soil seed bank of mining areas and other fragile habitats, and put forward the challenges we are facing with. It was expected that this paper could help to reinforce the soil seed bank research of China mining areas, and provide scientific guidelines for taking great advantage of the significant roles of soil seed bank in land reclamation and vegetation restoration in the future.

Clay illuviation provides a long-term sink for C sequestration in subsoils

NASA Astrophysics Data System (ADS)

Torres-Sallan, Gemma; Schulte, Rogier P. O.; Lanigan, Gary J.; Byrne, Kenneth A.; Reidy, Brian; Simó, Iolanda; Six, Johan; Creamer, Rachel E.

2017-04-01

Soil plays a key role in the global carbon (C) cycle. Most current assessments of SOC stocks and the guidelines given by Intergovernmental Panel on Climate Change (IPCC) focus on the top 30 cm of soil. Our research shows that, when considering only total quantities, most of the SOC stocks are found in this top layer. However, not all forms of SOC are equally valuable as long-term stable stores of carbon: the majority of SOC is available for mineralisation and can potentially be re-emitted to the atmosphere. SOC associated with micro-aggregates and silt plus clay fractions is more stable and therefore represents a long-term carbon store. Our research shows that most of this stable carbon is located at depths below 30 cm (42% of subsoil SOC is located in microaggregates and silt and clay, compared to 16% in the topsoil), specifically in soils that are subject to clay illuviation. This has implications for land management decisions in temperate grassland regions, defining the trade-offs between primary productivity and C emissions in clay-illuviated soils, as a result of drainage. Therefore, climate smart land management should consider the balance between SOC stabilisation in topsoils for productivity versus sequestration in subsoils for climate mitigation.

Precipitation overrides warming in mediating soil nitrogen pools in an alpine grassland ecosystem on the Tibetan Plateau

PubMed Central

Lin, Li; Zhu, Biao; Chen, Chengrong; Zhang, Zhenhua; Wang, Qi-Bing; He, Jin-Sheng

2016-01-01

Soils in the alpine grassland store a large amount of nitrogen (N) due to slow decomposition. However, the decomposition could be affected by climate change, which has profound impacts on soil N cycling. We investigated the changes of soil total N and five labile N stocks in the topsoil, the subsoil and the entire soil profile in response to three years of experimental warming and altered precipitation in a Tibetan alpine grassland. We found that warming significantly increased soil nitrate N stock and decreased microbial biomass N (MBN) stock. Increased precipitation reduced nitrate N, dissolved organic N and amino acid N stocks, but increased MBN stock in the topsoil. No change in soil total N was detected under warming and altered precipitation regimes. Redundancy analysis further revealed that soil moisture (26.3%) overrode soil temperature (10.4%) in explaining the variations of soil N stocks across the treatments. Our results suggest that precipitation exerted stronger influence than warming on soil N pools in this mesic and high-elevation grassland ecosystem. This indicates that the projected rise in future precipitation may lead to a significant loss of dissolved soil N pools by stimulating the biogeochemical processes in this alpine grassland. PMID:27527683

Geomorphological impact on agroforestry systems in the interior highlands of Nicaragua, Central America

NASA Astrophysics Data System (ADS)

Mentler, Axel; Wriessnig, Karin; Ottner, Franz; Schomakers, Jasmin; Benavides González, Álvaro; Cisne Contreras, José Dolores; Querol Lipcovich, Daniel

2013-04-01

Cerro el Castillo is located in the NW of Nicaragua, Central America, close to the border of Honduras (Provincia Central de las Cordilleras) at 1000-1200m above sea level. In this region, small and medium-sized farms are agroforestry systems with mangos, avocados, coffee, papayas, bananas, strawberries, maize, pumpkins, beans and other vegetables. The production systems are strongly linked to facilities for raising small domestic animals and cows. Main regional agricultural production problems are steep slopes, soil erosion, varying precipitation and distribution, water management and the unstable family income. An investigation of topsoil properties with comparable management systems showed on small scales significant differences in key values of soil chemistry and mineralogy. The outline of the analytical parameters included determination of pH, electrical conductivity (EC), cation exchange capacity (CEC), organic carbon (TOC), dissolved organic carbon (DOC), total nitrogen (TN) and dissolved nitrogen (DN) in soil solution, and plant available nutrients (P and K). The soil's mineralogical composition was determined by X-ray diffraction analysis. The area is a highly weathered karst landscape within a tropical limestone region displaying different amounts of volcanic pyroclastic parent material. The dominant Nitisoils and Andosols show degraded argic and andic horizons along the upper half of the mountainside. The pH values in the topsoil are moderate from pH 5.0 to 5.6. The upland topsoil is decalcified and the amount of plant available phosphorous is very low with significant low Ca concentration at the sorption complex. The mineralogical composition points to the high weathering intensity of this area (high content of kaolinite and a lower concentration of potassium and plagioclase feldspars and andesite). Along the upper half of the mountain, the soil profiles show wider C:N ratios and lower amounts of organic matter. Topsoil at lower altitude and with a lower slope is influenced by accumulation of pyroclastic material. Theses soils can be characterized through a closer C:N ratio, higher pH (5.7-6.2) values, and plant available phosphorus reach values of 23 mg/kg. The mineralogical analyses illustrated less weathered volcanic material here and in the investigated samples zeolithe, smectite and a higher amount of plagioclase could be found. Cristobalite und pyroxene could be detected in all samples and indicate the influence of volcanic activity. Smectite und zeolithe are reason for the higher CEC values of these soils. Erosion and intensive tropical weathering processes including solutional weathering of limestones decline production potential at higher altitudes. Agroforestry systems are the most adapted systems for sustainable plant production systems in this area. Phosphorus release of soil is strongly influenced by the geomorphology of this landscape. Limiting parameters of this production system is the amount and the distribution of precipitation. The impact of global change to this specific area of Nicaragua will lead to extreme values of local precipitation events and an increase in temperature. If these events continue important production areas for optimum coffee production in agroforestry systems in Central America will be lost. Acknowledgement: This project was financed through the Austrian APPEAR program (OEAD).

Impact of ancient charcoal kilns on chemical properties of several forest soils after 2 centuries

NASA Astrophysics Data System (ADS)

Dufey, Joseph; Hardy, Brieuc; Cornelis, Jean-Thomas

2014-05-01

Pyrogenic carbon plays a major role in soil biogeochemical processes and carbon budgets. Until the early 19th century, charcoal was the unique combustible used for iron metallurgy in Wallonia (Belgium). Traditional charcoal kilns were built directly in the forest: wood logs were piled into a mound and isolated from air oxygen with a covering of vegetation residues and soil before setting fire, inducing wood pyrolysis. Nowadays, ancient wood-charring platforms are still easy to identify on the forest floor as heightened domes of 10 meters in diameter characterized by a very dark topsoil horizon containing charcoal dust and fragments. Our goal is to assess the effects of wood charring at mound kiln sites on the properties of various forest soil types in Wallonia (Belgium), after two centuries. We sampled soil by horizon in 18 ancient kiln sites to 1.20 meter depth. The adjacent charcoal-unaffected soils were sampled the same way. We also collected recent charcoal fragments and topsoil samples from a still active charcoal kiln located close to Dole (France) to apprehend the evolution of soil properties over time. The pH, total carbon (C) and nitrogen (N) content, available phosphorus (Pav), cation exchange capacity at pH 7 (CEC), exchangeable cations (Ca++, Mg++, K+, Na+) and loss on ignition at 550°C (LI550) were measured on each soil sample. We separated the soil profiles in 5 groups based on the nature of soil substrate and pedogenesis for interpretation of the results. We show that the total carbon stock is significantly increased at kiln sites due to higher C concentrations and greater depth of the organo-mineral horizon. The C/N ratio in charcoal-enriched soil horizons is significantly higher than in the neighboring reference soils but clearly attenuated compared to pure wood-charcoal fragments. The CEC is higher in the charcoal-enriched soil horizons, not only due to higher C concentrations but also to increased CEC by carbon unit at kiln sites. The high negative charge of charcoal results from surface oxidation processes over time. This charge varies over quite a wide range of values according to soil type, which might be explained by the nature of the charred wood. The surface soil horizons at kiln site show a completely desaturated exchange complex, comparable to the reference soils. However, the raise of the base saturation in the underlying horizons reflects the past liming effect of ashes produced by wood charring that has been completely erased from the topsoil in 200 years. Exchangeable K+ in the topsoil layers of kiln sites is very low, which can be related to an enhanced selectivity for Mg++ and Ca++ on the exchange complex of old charred material. Similarly, very little Pav is extracted from charcoal-enriched horizons, suggesting that Pav is either reduced in quantity or in availability. Our data clearly highlight the long-term effect of the accumulation of charred material on the evolution of soil chemical properties due to charcoal ageing and nutrient leaching.

Quality assessment for brick making of the bleached topsoil of Vertic Planosols in the south-western Ethiopian Highlands

NASA Astrophysics Data System (ADS)

Dumon, Mathijs; Vandemeulebroeke, Laure; Van Daele, Kim; Regassa Tolossa, Alemayehu; Proost, Vicky; Van Ranst, Eric

2013-04-01

Planosols are a very common soil type in Ethiopia. The Vertic Planosols of the south-western Highlands are typical examples of duplex soils, characterized by a bleached, silty top horizon abruptly overlying a heavy clay subsoil. The bleached topsoil material is of local economic importance as it is extensively used for brick making. The aim of this research was to assess the quality of locally produced bricks following Ethiopian and European quality standards, and formulating recommendations to improve the quality of the bricks. After a reconnaissance field survey three brick production sites, Bore, Serbo and Marawaa, were selected. At each site the bleached topsoil was sampled for physico-chemical analyses and locally produced bricks were collected for further testing. The production process, documented by interviewing locals, consists of excavating the bleached topsoil, manual mixing with water, shaping using an ash-covered wooden mould, trimming using an iron wire, and drying in open air. About 30,000 dried bricks are then piled up to form a rectangular field-oven and fired for about two and a half days. It was observed and admitted by the locals that about 10% of the produced bricks are lost due to severe cracking and/or melting on the inside of the field oven. On the other hand, some of the bricks on the outside of the field oven were not sufficiently fired. Physico-chemical (texture, total elemental chemical composition, carbonate content, total carbon content, sulphur content, cation exchange capacity, total specific surface) and mineralogical (XRD, DSC, thermogravimetry, dilatometry, optical microscopy) analyses were carried out. Additionally, the locally produced bricks were physically characterised by their dimensions, initial rate of water absorption (IRWA), water absorption after 24h and compressive strength. Based on the observed properties for the soil material and the locally produced bricks, mixtures of soil samples and a sand additive were made in an attempt to improve the quality of the bricks. In addition, the effect of the moulding method was taken into account by making both hand-moulded and pressure-moulded bricks from both the reference soil material and the improved mixture. These new bricks were also tested on water absorption, drying, firing and total shrinkage and compressive strength. The analytical results indicated the locally produced bricks are quite strong, but absorb too much water when matched with European and Ethiopian standards. New bricks made from the improved mixtures show a significantly lower water absorption. Compressive strength on the other hand, is slightly reduced for these test units, but still above standard levels. A lower variability in measured values when using pressure-moulded test units compared to hand-moulded test units indicated the former result in a more uniform quality of bricks. It can be concluded that the current locally applied methods and materials produce a moderate quality brick on average, with large variation in the quality. Use of a sandy additive, adjusting the moulding method and improving the field oven layout to achieve a more homogeneous temperature distribution, are surely options to improve the quality of the bricks produced from these bleached materials.

Distribution of radioactive Cesium in trees and effect of decontamination of forest contaminated by the Fukushima nuclear accident

DOE Office of Scientific and Technical Information (OSTI.GOV)

Iijima, K.; Funaki, H.; Tokizawa, T.

In decontamination pilot projects conducted by Japan Atomic Energy Agency (JAEA), many different techniques were tested to determine their applicability to remediate areas evacuated after the Fukushima Daiichi nuclear accident following the Great Tohoku earthquake and tsunami of March 11, 2011. In addition to buildings, roads and farmland, the forest adjacent to living areas was one of the main decontamination targets. The projects evaluated the radioactive contamination of trees and the effectiveness of decontaminating a highly contaminated evergreen forest. This forest was located 1.3 km southwest of the Fukushima Daiichi Nuclear Power Plant and is dominated by Japanese cedar treesmore » and fir trees. As the first step, three Japanese cedar trees and three fir trees were cut down and the distributions of radioactive cesium (Cs) were measured in each. The total concentrations of {sup 134}Cs and {sup 137}Cs in the leaves and branches were about 1 MBq/kg for both cedar and fir trees, and were appreciably higher than in the bark for cedar. The concentrations in the outer part of the trunks (under the bark) were lower, on the order of 10 kBq/kg, and those in the core of the trunks were lower than 1 kBq/kg for both kinds of trees. The observation that the Cs concentrations are higher in the outer part of trees, is compatible with the assumption that radio-Cs was mostly adsorbed on the surface of trees and partly penetrated into the trunks through the bark. Evolution of air dose rates in a 100 x 60 m pasture adjacent to the forest was monitored during decontamination of the forest and of the pasture itself. The dose rates in the pasture decreased drastically after stripping contaminated topsoil from the pasture and decreased slightly more after stripping contaminated topsoil of the forest floor and pruning the trees. Cutting down and removing 84 trees in the outermost area (10- m width) of the forest also slightly decreased these dose rates. After decontamination, the residual dose rates around the highly contaminated forest were mostly attributed to radioactive Cs existing in or on trees and topsoil in the untouched forest beyond the decontaminated area. (authors)« less

Potential of SENTINEL-2 images for predicting common topsoil properties over Temperate and Mediterranean agroecosystems

NASA Astrophysics Data System (ADS)

Vaudour, Emmanuelle; Gomez, Cécile; Fouad, Youssef; Gilliot, Jean-Marc; Lagacherie, Philippe

2017-04-01

This study aimed at exploring the potential of SENTINEL-2 (S2A) multispectral satellite images for predicting several topsoil properties in two contrasted environments: a temperate region marked by intensive annual crop cultivation and soils derived from either loess or colluvium and/or marine limestone or chalk for one part (Versailles Plain, 221 km2), and a Mediterranean region marked by vineyard cultivation and soils derived from either lacustrine limestone, calcareous sandstones, colluvium, or alluvial deposits (La Peyne catchment, 48 km2) for the other part. Two S2A images (acquired in mid-March 2016 over each site) were atmospherically corrected. Then NDVI was computed and thresholded (0.35) in order to extract bare soils. Prediction models of soil properties based on partial least squares regressions (PLSR) were built from S2A spectra of 72 and 143 sampling locations in the Versailles Plain and La Peyne catchment, respectively. Ten soil properties were investigated in both regions: pH, cation exchange capacity (CEC), five texture fractions (clay, coarse silt, fine silt, coarse sand and fine sand), iron, calcium carbonate and soil organic carbon (SOC) in the tilled horizon. Predictive abilities were studied according to R_cv2 and ratio of performance to deviation (RPD). Intermediate to near intermediate performances of prediction (R_cv2 and RPD between 0.28-0.70 and 1.19-1.85 respectively) were obtained for 6 topsoil properties: clay, iron, SOC, CEC, pH, coarse silt. In the Versailles Plain, 5 out of these properties could be predicted (by decreasing performance, CEC, SOC, pH, clay, coarse silt), while there were 4 predictable properties for La Peyne catchment (Iron, clay, CEC, coarse silt). The amount in coarse fragment content appeared to impact prediction error for iron content over La Peyne, while it influenced prediction error for SOC content over the Versailles Plain along with calcium carbonate content. A spatial structure of the estimated soil properties for bare soils pixels was highlighted, which promises further improvements in spatial prediction models for these properties. This work was carried out in the framework of both the TOSCA-CES "Cartographie Numérique des sols" and the PLEIADES-CO projects of the French Space Agency (CNES).

Evaluation of environmental magnetic pollution screening in soils of basaltic origin: results from Nashik Thermal Power Station, Maharashtra, India.

PubMed

Basavaiah, N; Blaha, U; Das, P K; Deenadayalan, K; Sadashiv, M B; Schulz, H

2011-08-01

Soils of basaltic origin cause difficulties in environmental magnetic screening for heavy metal pollution due to their natural high background values. Magnetic parameters and heavy metal content of highly magnetic topsoils from the Deccan Trap basalts are investigated to assess their potential for use in environmental magnetic pollution screening. This work extends the fast and cost-effective magnetic pollution screening techniques into soils with high natural magnetic signals. Fifty-five topsoil samples from N-S and W-E transects were collected and subdivided according to grain size using wet sieving technique. Magnetic susceptibility, soft isothermal remanent magnetization (Soft IRM), thermomagnetic analysis, scanning electron microscopy (SEM), and heavy metal analysis were performed on the samples. Magnetic analyses reveal a significant input of anthropogenic magnetic particulate matter within 6 km of the power plant and the adjacent ash pond. Results depend strongly on the stage of soil development and vary spatially. While results in the W, E, and S directions are easily interpretable, in the N direction, the contribution of the anthropogenic magnetic matter is difficult to assess due to high magnetic background values, less developed soils, and a more limited contribution from the fly ash sources. Prevailing winds towards directions with more enhanced values seem to have a certain effect on particulate matter accumulation in the topsoil. Thermomagnetic measurements show Verwey transition and Hopkinson peak, thus proving the presence of ferrimagnetic mineral phases close to the pollution source. A quantitative decrease of the anthropogenic ferrimagnetic mineral concentration with increased distance is evident in Soft IRM measurements. SEM investigations of quantitatively extracted magnetic particles confirm the fly ash distribution pattern obtained from the magnetic and heavy metal analyses. Evaluation of magnetic and chemical data in concert with the Pollution Load IndiceS (PLIS) of Pb, Zn, and Cu reveals a good relationship between magnetic susceptibility and the metal content. Integrated approaches in data acquisition of magnetic and chemical parameters enable the application of magnetic screening methods in highly magnetic soils. Combined data evaluation allows identification of sampling sites that are affected by human activity, through the deviation of the magnetic and chemical data from the general trend. It is shown that integrative analysis of magnetic parameters and a limited metal concentration dataset can enhance the quality of the output of environmental magnetic pollution screening significantly.

Deep soil layer is fundamental for evaluating carbon accumulation in agroecosystems

NASA Astrophysics Data System (ADS)

Dal Ferro, Nicola; Morari, Francesco; Simonetti, Gianluca; Polese, Riccardo; Berti, Antonio

2015-04-01

Soil organic carbon (SOC) is essential to secure key ecosystem services such as the provision of food and other biomass production, the filtering, buffering and transformation capacity and the climate regulation. It has been estimated that approximately 57% of the globally emitted C (8.7 Gt y-1) to the atmosphere is adsorbed by biospheric C pools, ascertaining the potential soil C sink capacity of managed ecosystems at 55 to 78 Gt, of which only 50 to 66% attainable. Therefore it is essential the full knowledge of soil management practices that can affect SOC dynamics and, in turn, climate change. Several studies focussed on the evaluation of the best cropping management practices to accumulate C in the soil profile. Nevertheless, in most cases soil analyses were made in the topsoil (generally in the 0-30 cm layer), ignoring the effect of C translocation in the deeper soil profile as a result of tillage practices, crop root deepening etc. In this context, in a long-term experiment established in the early 1960s, we quantified the SOC accumulation within the soil profile (0-90 cm) and evaluate the effects of different cropping system on SOC dynamics. The experiment is located at the experimental farm of the University of Padova, in northeastern Italy. The trial compares four rotations with three levels of mineral fertilisation and with or without organic fertilisation. The rotations considered are: continuous crops (grain maize, forage maize, winter wheat and permanent meadow); two-year (maize-wheat); four-year (sugarbeet, soybean, wheat, maize) and six-year (maize, sugarbeet, maize, wheat, alfalfa, alfalfa) with different levels of mineral, organic and mixed fertilisations. Crops with superficially developed rooting systems (e.g. permanent meadow) highly increased SOC only in the topsoil. This effect was enhanced by the contribution of organic amendment-C. Root-derived carbon played a pivotal role also in the deepest soil profile (60-90 cm) by increasing the SOC translocation. Considering the whole profile, the highest C accumulation was observed in cropping systems with high biomass production and deep rooting systems. Results indicated that for estimating the effects of cropping systems and agricultural practices on C accumulation, analyses in the topsoil can be misleading and it is necessary to consider the whole profile.

Whole watershed quantification of net carbon fluxes by erosion and deposition within the Christina River Basin Critical Zone Observatory

NASA Astrophysics Data System (ADS)

Aufdenkampe, A. K.; Karwan, D. L.; Aalto, R. E.; Marquard, J.; Yoo, K.; Wenell, B.; Chen, C.

2012-12-01

We have proposed that the rate at which fresh, carbon-free minerals are delivered to and mix with fresh organic matter determines the rate of carbon preservation at a watershed scale (Aufdenkampe et al. 2011). Although many studies have examined the role of erosion in carbon balances, none consider that fresh carbon and fresh minerals interact. We believe that this mechanism may be a dominant sequestration process in watersheds with strong anthropogenic impacts. Our hypothesis - that the rate of mixing fresh carbon with fresh, carbon-free minerals is a primary control on watershed-scale carbon sequestration - is central to our Christina River Basin Critical Zone Observatory project (CRB-CZO, http://www.udel.edu/czo/). The Christina River Basin spans 1440 km2 from piedmont to Atlantic coastal plain physiographic provinces in the states of Pennsylvania and Delaware, and experienced intensive deforestation and land use beginning in the colonial period of the USA. Here we present a synthesis of multi-disciplinary data from the CRB-CZO on materials as they are transported from sapprolite to topsoils to colluvium to suspended solids to floodplains, wetlands and eventually to the Delaware Bay estuary. At the heart of our analysis is a spatially-integrated, flux-weighted comparison of the organic carbon to mineral surface area ratio (OC/SA) of erosion source materials versus transported and deposited materials. Because source end-members - such as forest topsoils, farmed topsoils, gullied subsoils and stream banks - represent a wide distribution of initial, pre-erosion OC/SA, we quantify source contributions using geochemical sediment fingerprinting approaches (Walling 2005). Analytes used for sediment fingerprinting include: total mineral elemental composition (including rare earth elements), fallout radioisotope activity for common erosion tracers (beryllium-7, beryllium-10, lead-210, cesium-137), particle size distribution and mineral specific surface area, in addition to organic carbon and nitrogen content with stable isotope (13C, 15N) and radiocarbon (14C) abundance to quantify OC/SA and organic carbon sources and mean age. We then use multivariate mixing model analysis to quantify the fractional contribution of each source end-member to each sample of suspended or deposited sediments. Last, we calculate a predicted OC/SA based on source end-member mixing and compare to the measured OC/SA to quantify net change in mineral complexed carbon.

How do peat type, sand addition and soil moisture influence the soil organic matter mineralization in anthropogenically disturbed organic soils?

NASA Astrophysics Data System (ADS)

Säurich, Annelie; Tiemeyer, Bärbel; Don, Axel; Burkart, Stefan

2017-04-01

Drained peatlands are hotspots of carbon dioxide (CO2) emissions from agriculture. As a consequence of both drainage induced mineralization and anthropogenic sand mixing, large areas of former peatlands under agricultural use contain soil organic carbon (SOC) at the boundary between mineral and organic soils. Studies on SOC dynamics of such "low carbon organic soils" are rare as the focus of previous studies was mainly either on mineral soils or "true" peat soil. However, the variability of CO2 emissions increases with disturbance and therefore, we have yet to understand the reasons behind the relatively high CO2 emissions of these soils. Peat properties, soil organic matter (SOM) quality and water content are obviously influencing the rate of CO2 emissions, but a systematic evaluation of the hydrological and biogeochemical drivers for mineralization of disturbed peatlands is missing. With this incubation experiment, we aim at assessing the drivers of the high variability of CO2 emissions from strongly anthropogenically disturbed organic soil by systematically comparing strongly degraded peat with and without addition of sand under different moisture conditions and for different peat types. The selection of samples was based on results of a previous incubation study, using disturbed samples from the German Agricultural Soil Inventory. We sampled undisturbed soil columns from topsoil and subsoil (three replicates of each) of ten peatland sites all used as grassland. Peat types comprise six fens (sedge, Phragmites and wood peat) and four bogs (Sphagnum peat). All sites have an intact peat horizon that is permanently below groundwater level and a strongly disturbed topsoil horizon. Three of the fen and two of the bog sites have a topsoil horizon altered by sand-mixing. In addition the soil profile was mapped and samples for the determination of soil hydraulic properties were collected. All 64 soil columns (including four additional reference samples) will be installed in a microcosm system under a constant temperature of 10°C. The water-saturated soil columns will be drained via suction plates at the bottom of the columns by stepwise increase of the suction. The head space of the soil columns will be permanently flushed with moistened synthetic air and CO2 concentrations will be measured via online gas chromatography. First results will be presented.

Lead Contamination and Source Characterization in Soils Around a Lead-Zinc Smelting Plant in a Near-Urban Environment in Baoji, China.

PubMed

Deng, Wenbo; Li, Xuxiang; An, Zhisheng; Yang, Liu

2016-11-01

Economic reforms in China since 1978 have promoted nationwide socioeconomic advancement but led to a considerable amount of environmental pollution. The distribution and sources of Pb in a typical peri-urban industrial part of Baoji, China, were assessed by determining the Pb contents and isotopic compositions in 52 topsoil samples from the study area. The topsoil samples were polluted averagely with 40.88 mg Pb kg -1 , was 1.86 times higher than the Pb content of local background soil (22.04 mg kg -1 ). Pb isotopic compositions were determined by analyzing samples prepared using total digestion and acid extraction methods. Radiogenic isotopes contributed more to the Pb concentrations in the acid extracts than in the total digests. This was shown by the 207/206 Pb and 208/206 Pb ratios, which were 0.845-0.88 and 2.088-2.128, respectively, in the acid extracts and 0.841-0.875 and 2.086-2.125, respectively, in the total digests. This indicates that anthropogenic sources of Pb could be identified more sensitively in acid extracts than in total digests. The Pb isotope ratios showed that burning coal and smelting ore are the predominant anthropogenic sources of Pb in the study area, i.e., a lead-zinc smelter and a coking plant are major sources of Pb in the study area.

Post-mining deterioration of bauxite overburdens in Jamaica: storage methods or subsoil dilution?

NASA Astrophysics Data System (ADS)

Harris, Mark A.; Omoregie, Samson N.

2008-03-01

Rapid degradation of disturbed soil from a karst bauxite mine in Jamaica was recorded. Substantial macronutrient losses were incurred during a short (1 month) or a long (12 months) storage of the replaced topsoils during frequent wet/dry changes. The results suggested very high rates (>70% in the first year) of soil degradation from storage, alongside moderate rates (30%) within the same storage dump. However, higher levels of soil organic matter (SOM) were indicated just below the surface, compared with the surface horizons. It was unlikely that under a high leaching humid tropical rainfall regime, natural degradation processes could have re-emplaced such material firmly intact in the 15-30 cm zone. It was therefore concluded that these SOM anomalies were due to mechanical dilution of surface soil with subsoil material during overburden removal and emplacement rather than from long storage. Increasing the soil organic content during storage could be one corrective approach. However, it is far less costly to exercise greater care to apply more precise overburden removal and emplacement techniques initially, than it is to correct the results of topsoil contamination with subsoil. Although this study was limited to one mine, in the context of imminent large-scale mining expansion and current practices, further investigations are needed to accurately ascertain the proportion of similar subsoil contamination in other bauxite-mined sites.

Distribution and habitat utilization of the gopher tortoise tick (Amblyomma tuberculatum) in southern Mississippi

USGS Publications Warehouse

Ennen, Joshua R.; Qualls, Carl P.

2011-01-01

The distribution of the gopher tortoise tick (Amblyomma tuberculatum) has been considered intrinsically linked to the distribution of its primary host, gopher tortoises (Gopherus polyphemus). However, the presence of G. polyphemus does not always equate to the presence of A. tuberculatum. There is a paucity of data on the ecology, habitat preferences, and distribution of A. tuberculatum. The goals of this study were to assess the distribution of A. tuberculatum in southern Mississippi and to determine which, if any, habitat parameters explain the distribution pattern of A. tuberculatum. During 2006-2007, we examined 13 G. polyphemus populations in southern Mississippi for the presence of A. tuberculatum, and we measured a suite of habitat parameters at each site. Only 23% of the G. polyphemus populations supported A. tuberculatum, suggesting a more restricted distribution than its host. The results of our multivariate analyses identified several habitat variables, e.g., depth of sand and percentage of sand in the topsoil and burrow apron, as being important in discriminating between sites with, and without, A. tuberculatum. Amblyomma tuberculatum was only found at sites with a mean sand depth of >100 cm and a mean percentage of topsoil and burrow apron sand composition >94.0 and 92.4, respectively. Thus, environmental factors, and not just its host's range, seem to influence the distribution of A. tuberculatum.

Distribution and habitat utilization of the gopher tortoise tick (Amblyomma tuberculatum) in Southern Mississippi

USGS Publications Warehouse

Ennen, J.R.; Qualls, C.P.

2011-01-01

The distribution of the gopher tortoise tick (Amblyomma tuberculatum) has been considered intrinsically linked to the distribution of its primary host, gopher tortoises (Gopherus polyphemus). However, the presence of G. polyphemus does not always equate to the presence of A. tuberculatum. There is a paucity of data on the ecology, habitat preferences, and distribution of A. tuberculatum. The goals of this study were to assess the distribution of A. tuberculatum in southern Mississippi and to determine which, if any, habitat parameters explain the distribution pattern of A. tuberculatum. During 2006-2007, we examined 13 G. polyphemus populations in southern Mississippi for the presence of A. tuberculatum, and we measured a suite of habitat parameters at each site. Only 23% of the G. polyphemus populations supported A. tuberculatum, suggesting a more restricted distribution than its host. The results of our multivariate analyses identified several habitat variables, e.g., depth of sand and percentage of sand in the topsoil and burrow apron, as being important in discriminating between sites with, and without, A. tuberculatum. Amblyomma tuberculatum was only found at sites with a mean sand depth of >100 cm and a mean percentage of topsoil and burrow apron sand composition >94.0 and 92.4, respectively. Thus, environmental factors, and not just its host's range, seem to influence the distribution of A. tuberculatum. ?? American Society of Parasitologists 2011.

Simultaneous immobilization of metals and arsenic in acidic polluted soils near a copper smelter in central Chile.

PubMed

Cárcamo, Valeska; Bustamante, Elena; Trangolao, Elizabeth; de la Fuente, Luz María; Mench, Michel; Neaman, Alexander; Ginocchio, Rosanna

2012-05-01

Acidic and metal(oid)-rich topsoils resulted after 34 years of continuous operations of a copper smelter in the Puchuncaví valley, central Chile. Currently, large-scale remediation actions for simultaneous in situ immobilization of metals and As are needed to reduce environmental risks of polluted soils. Aided phytostabilization is a cost-effective alternative, but adequate local available soil amendments have to be identified and management options have to be defined. Efficacy of seashell grit (SG), biosolids (B), natural zeolite (Z), and iron-activated zeolite (AZ), either alone or in mixtures, was evaluated for reducing metal (Cu and Zn) and As solubilization in polluted soils under laboratory conditions. Perennial ryegrass was used to test phytotoxicity of experimental substrates. Soil neutralization to a pH of 6.5 with SG, with or without incorporation of AZ, significantly reduces metal (Cu and Zn) solubilization without affecting As solubilization in soil pore water; furthermore, it eliminates phytotoxicity and excessive metal(oid) accumulation in aerial plant tissues. Addition of B or Z to SG-amended soil does not further reduce metal solubilization into soil pore water, but increase As solubilization due to excessive soil neutralization (pH > 6.5); however, no significant As increase occurs in aerial plant tissues. Simultaneous in situ immobilization of metal(oid) in acidic topsoils is possible through aided phytostabilization.

Pollution assessment and source apportionment of heavy metals in contaminated site soils

NASA Astrophysics Data System (ADS)

Zheng, Hongbo; Ma, Yan

2018-03-01

Pollution characteristics of heavy metals in soil were analyzed with a typical contaminated site as the case area. The pollution degree of the element was evaluated by indexes of geoaccumulation (Igeo). The potential ecological risk of heavy metals was assessed with potential ecological risk index model. Principal component analysis (PCA) model was simultaneously carried out to identify the main sources of heavy metals in topsoils. The results indicated that: 1. Mean values of 11 kinds of metals in topsoils were greater than respective soil background values, following the order: Zn>Pb>V>Cr>Cu>Ni>Co>As>Sb>Cd>Hg. Heavy metals with a certain accumulation in the research area were significantly affected by external factors. 2. Igeo results showed that Cd and Zn reached strongly polluted degree, while Pb with moderately to strongly polluted, Sb and Hg with moderately polluted, Cu, Co, Ni and Cr with unpolluted to moderately polluted, V and As with un-polluted. 3. Potential ecological risk assessment showed the degree of ecological risk with Cd at very high risk, Hg at high risk, Pb at moderate risk and others at low risk. The comprehensive risk of all the metals was very high. 4. PCA got three main sources with contributions, including industrial activities (44.18%), traffic and burning dust (26.68%) and soil parent materials (12.20%).

The microbe-mediated mechanisms affecting topsoil carbon stock in Tibetan grasslands

DOE PAGES

Yue, Haowei; Wang, Mengmeng; Wang, Shiping; ...

2015-02-17

Warming has been shown to cause soil carbon (C) loss in northern grasslands owing to accelerated microbial decomposition that offsets increased grass productivity. Yet, a multi-decadal survey indicated that the surface soil C stock in Tibetan alpine grasslands remained relatively stable. To investigate this inconsistency, we analyzed the feedback responses of soil microbial communities to simulated warming by soil transplant in Tibetan grasslands. Microbial functional diversity decreased in response to warming, whereas microbial community structure did not correlate with changes in temperature. The relative abundance of catabolic genes associated with nitrogen (N) and C cycling decreased with warming, most notablymore » in genes encoding enzymes associated with more recalcitrant C substrates. By contrast, genes associated with C fixation increased in relative abundance. The relative abundance of genes associated with urease, glutamate dehydrogenase and ammonia monoxygenase ( ureC, gdh and amoA) were significantly correlated with N 2O efflux. These results suggest that unlike arid/semiarid grasslands, Tibetan grasslands maintain negative feedback mechanisms that preserve terrestrial C and N pools. To examine whether these trends were applicable to the whole plateau, we included these measurements in a model and verified that topsoil C stocks remained relatively stable. Thus, by establishing linkages between microbial metabolic potential and soil biogeochemical processes, we conclude that long-term C loss in Tibetan grasslands is ameliorated by a reduction in microbial decomposition of recalcitrant C substrates.« less

Combination of magnetic parameters and heavy metals to discriminate soil-contamination sources in Yinchuan--a typical oasis city of Northwestern China.

PubMed

Xia, Dunsheng; Wang, Bo; Yu, Ye; Jia, Jia; Nie, Yan; Wang, Xin; Xu, Shujing

2014-07-01

Various industrial processes and vehicular traffic result in harmful emissions containing both magnetic minerals and heavy metals. In this study, we investigated the levels of magnetic and heavy metal contamination of topsoils from Yinchuan city in northwestern China. The results demonstrate that magnetic mineral assemblages in the topsoil are dominated by pseudo-single domain (PSD) and multi-domain (MD) magnetite. The concentrations of anthropogenic heavy metals (Cr, Cu, Pb and Zn) and the magnetic properties of χlf, SIRM, χARM, and 'SOFT' and 'HARD' remanence are significantly correlated, suggesting that the magnetic minerals and heavy metals have common sources. Combined use of principal components and fuzzy cluster analysis of the magnetic and chemical data set indicates that the magnetic and geochemical properties of the particulates emitted from different sources vary significantly. Samples from university campus and residential areas are mainly affected by crustal material, with low concentrations of magnetic minerals and heavy metals, while industrial pollution sources are characterized by high concentrations of coarse magnetite and Cr, Cu, Pb and Zn. Traffic pollution is characterized by Pb and Zn, and magnetite. Magnetic measurements of soils are capable of differentiating sources of magnetic minerals and heavy metals from industrial processes, vehicle fleets and soil parent material. Copyright © 2014 Elsevier B.V. All rights reserved.

Solid-state 13C NMR experiments reveal effects of aggregate size on the chemical composition of particulate organic matter in grazed steppe soils

NASA Astrophysics Data System (ADS)

Steffens, M.; Kölbl, A.; Kögel-Knabner, I.

2009-04-01

Grazing is one of the most important factors that may reduce soil organic matter (SOM) stocks and subsequently deteriorate aggregate stability in grassland topsoils. Land use management and grazing reduction are assumed to increase the input of OM, improve the soil aggregation and change species composition of vegetation (changes depth of OM input). Many studies have evaluated the impact of grazing cessation on SOM quantity. But until today little is known about the impact of grazing cessation on the chemical quality of SOM in density fractions, aggregate size classes and different horizons. The central aim of this study was to analyse the quality of SOM fractions in differently sized aggregates and horizons as affected by increased inputs of organic matter due to grazing exclusion. We applied a combined aggregate size, density and particle size fractionation procedure to sandy steppe topsoils with different organic matter inputs due to different grazing intensities (continuously grazed = Cg, winter grazing = Wg, ungrazed since 1999 = Ug99, ungrazed since 1979 = Ug79). Three different particulate organic matter (POM; free POM, in aggregate occluded POM and small in aggregate occluded POM) and seven mineral-associated organic matter fractions were separated for each of three aggregate size classes (coarse = 2000-6300 m, medium = 630-2000 m and fine =

Magnetic Measurements of Atmospheric Dust Deposition in Soils

NASA Astrophysics Data System (ADS)

Kapička, Aleš; Petrovský, Eduard; Grison, Hana; Podrázský, Vilém; Křížek, Pavel

2010-05-01

Atmospheric dust of anthropogenic origin contains significant portion of minerals characterized by ferrimagnetic properties [1,2]. These minerals, mostly iron oxides, can serve as tracers of industrial pollutants in soil layers. Moreover, recent results, e.g., [3,4] show significant correlation between concentration-dependent magnetic parameters (e.g., low-field magnetic susceptibility) and concentration of heavy metals (e.g., Pb, Zn, Cd). In our paper we have investigated magnetic properties of depth soil profiles from Krušné hory Mountains (Czech Republic), which belong to a highly contaminated, so-called Black Triangle in central Europe. Emissions are determined by considerable concentration of big sources of pollution (power plants burning fossil fuel, metallurgical and chemical industry). Increased values of magnetic susceptibility (25 - 200 × 10-5 SI) were clearly identified in the top-soil layers. Thermomagnetic analyses and SEM observation indicate that the accumulated anthropogenic ferrimagnetics dominate these layers. Magnetic enhancement is limited to depths of 4-7 cm below the soil surface, usually in F-H or top of Ah soil horizons; deeper soil horizons contain mainly magnetically weak materials and are characterized by much lower values of susceptibility (up to 30 × 10-5 SI). Significant magnetic parameters (e.g., Curie temperature Tc) and SEM results of contaminated topsoils are comparable with magnetic parameters of atmospheric dust, collected (using high-volume samplers) at the same localities.

Influence of Dry Soil on the Ability of Formosan Subterranean Termites, Coptotermes formosanus, to Locate Food Sources

PubMed Central

Cornelius, Mary L.; Osbrink, Weste L.A.

2011-01-01

The effect of barriers of dry soil on the ability of Formosan subterranean termites, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae), to construct tunnels and find food was evaluated. Termite movement and wood consumption in a three—chambered apparatus were compared between treatments with dry soil in the center container and treatments where the soil in the center container was moist. When a wood block was located in the release container, termites fed significantly more on that block, regardless of treatment or soil type. In the treatment with dry clay, none of the termites tunneled through the dry clay barrier to reach the distal container. When termites had to tunnel through a barrier of dry sand, topsoil, or clay to reach the sole wood block, there was no effect on wood consumption for the sand treatment, but there was significantly less feeding on wood in the treatments with dry topsoil or clay. When foraging arenas had a section of dry sand in the center, the dry sand significantly reduced tunneling in the distal section after 3 days, but not after 10 days. There was a highly significant effect on the ability of termites to colonize food located in dry sand. Only one feeding station located in dry sand was colonized by termites, compared with 11 feeding stations located in moist sand. PMID:22239343

Assessing Lead, Nickel, and Zinc Pollution in Topsoil from a Historic Shooting Range Rehabilitated into a Public Urban Park

PubMed Central

Argyraki, Ariadne; Ornelas-Soto, Nancy

2017-01-01

Soil contamination is a persistent problem in the world. The redevelopment of a site with a historical deposition of metals might conceal the threat of remaining pollution, especially when the site has become a public place. In this study, human health risk assessment is performed after defining the concentrations of Pb, Ni, and Zn in the topsoil of a former shooting range rehabilitated into a public park in the Municipality of Kesariani (Athens, Greece). A methodology that uses inductively coupled plasma mass spectrometry (ICP-MS, 13 samples), another that uses portable X-ray fluorescence (XRF) following a dense sample design (91 samples), and a hybrid approach that combines both, were used to obtain the concentrations of the trace elements. The enrichment factor and geoacummulation index were calculated to define the degree of pollution of the site. The hazard quotient and cancer risk indicators were also computed to find the risk to which the population is exposed. The present study reveals high non-carcinogenic health risk due to Pb pollution with ingestion as the main exposure pathway. The carcinogenic risk for Pb is within tolerable limits, but the definition of land use might alter such a statement. Lastly, regarding Ni and Zn, the site is unpolluted and there is insignificant carcinogenic and non-carcinogenic risks. PMID:28665307

Assessing Lead, Nickel, and Zinc Pollution in Topsoil from a Historic Shooting Range Rehabilitated into a Public Urban Park.

PubMed

Urrutia-Goyes, Ricardo; Argyraki, Ariadne; Ornelas-Soto, Nancy

2017-06-30

Soil contamination is a persistent problem in the world. The redevelopment of a site with a historical deposition of metals might conceal the threat of remaining pollution, especially when the site has become a public place. In this study, human health risk assessment is performed after defining the concentrations of Pb, Ni, and Zn in the topsoil of a former shooting range rehabilitated into a public park in the Municipality of Kesariani (Athens, Greece). A methodology that uses inductively coupled plasma mass spectrometry (ICP-MS, 13 samples), another that uses portable X-ray fluorescence (XRF) following a dense sample design (91 samples), and a hybrid approach that combines both, were used to obtain the concentrations of the trace elements. The enrichment factor and geoacummulation index were calculated to define the degree of pollution of the site. The hazard quotient and cancer risk indicators were also computed to find the risk to which the population is exposed. The present study reveals high non-carcinogenic health risk due to Pb pollution with ingestion as the main exposure pathway. The carcinogenic risk for Pb is within tolerable limits, but the definition of land use might alter such a statement. Lastly, regarding Ni and Zn, the site is unpolluted and there is insignificant carcinogenic and non-carcinogenic risks.

Prolonged acid rain facilitates soil organic carbon accumulation in a mature forest in Southern China.

PubMed

Wu, Jianping; Liang, Guohua; Hui, Dafeng; Deng, Qi; Xiong, Xin; Qiu, Qingyan; Liu, Juxiu; Chu, Guowei; Zhou, Guoyi; Zhang, Deqiang

2016-02-15

With the continuing increase in anthropogenic activities, acid rain remains a serious environmental threat, especially in the fast developing areas such as southern China. To detect how prolonged deposition of acid rain would influence soil organic carbon accumulation in mature subtropical forests, we conducted a field experiment with simulated acid rain (SAR) treatments in a monsoon evergreen broadleaf forest at Dinghushan National Nature Reserve in southern China. Four levels of SAR treatments were set by irrigating plants with water of different pH values: CK (the control, local lake water, pH ≈ 4.5), T1 (water pH=4.0), T2 (water pH=3.5), and T3 (water pH=3.0). Results showed reduced pH measurements in the topsoil exposed to simulated acid rains due to soil acidification. Soil respiration, soil microbial biomass and litter decomposition rates were significantly decreased by the SAR treatments. As a result, T3 treatment significantly increased the total organic carbon by 24.5% in the topsoil compared to the control. Furthermore, surface soil became more stable as more recalcitrant organic matter was generated under the SAR treatments. Our results suggest that prolonged acid rain exposure may have the potential to facilitate soil organic carbon accumulation in the subtropical forest in southern China. Copyright © 2015 Elsevier B.V. All rights reserved.

Tall fescue production and nutrient status on southwest Virginia mine soils. [Festuca arundinadea Schreb

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roberts, J.A.; Daniels, W.L.; Bell, J.C.

Tall fescue (Festuca arundinacea Schreb.) is a hardy grass species commonly used in surface mine reclamation and soil conservation. This study documented changes in fescue production (five growing seasons) and nutrient status (three growing seasons) as influenced by spoil type and various amendments. In Exp. I, fescue growth and nutrient status on five mixes of fertilized sandstone (SS) and siltstone (SiS) spoils were compared. A 2:1 SS/SiS control and treatments of 112 Mg ha/sup -1/ sawdust, native topsoil, and 22, 56, 112, and 224 Mg ha/sup -1/ municipal sewage sludge were compared in Exp. II. Standing biomass was measured inmore » 1982-1984 and 1986 and tissue nutrient levels were measured in 1982-1984. High SiS spoils inhibited initial biomass production in Exp. I, but parent material effect diminished with time. All spoil mixes maintained adequate fescue production for five growing seasons, primarily due to small annual N additions (56 kg ha/sup -1/). In Exp. II, the highest yields were maintained on greater than or equal to 56 Mg ha/sup -1/ sludge treatments. Heavy metal uptake was not a problem, even in very high sludge treatments. Sludge-amended mine soils were superior to both native topsoil and inorganically fertilized spoils in their ability to sustain long-term fescue production without periodic augmentation.« less

Impact of land use change on soil carbon loss of the Sikkim Himalayan piedmont

NASA Astrophysics Data System (ADS)

Prokop, Pawel; Ploskonka, Dominik

2014-05-01

Natural and human causes of change in land use on soil carbon were studied at the outlet of the Tista River from the Sikkim Himalayas over the last 150 years. Analysis of topographic maps and satellite images indicates that the land reforms related to location of tea gardens in the piedmont caused rapid deforestation of terraces in the late 19th century. Continuous population growth after 1930 initiated the replacement of floodplain forest by rice cultivation. Both processes changed soil carbon content and intensified fluvial activity expressed through terrace erosion. The replacement of natural forest by tea cultivation reduced the soil carbon content within terraces from 1.95 kg to 1.77 kg (in 1 m of topsoil) respectively. The replacement of natural forest by rice reduced the soil carbon content within floodplains from 0.42 kg to 0.23 kg (in 1 m topsoil) respectively. Much more dangerous, was terrace erosion leading to permanent removal of sediment including soil. The total loss of soil carbon in a 1 m thick soil layer due to conversion of 5 km2 forest to tea cultivation was about 900 t between 1930 and 2010. While the total soil carbon removed due to 1.8 km2 terrace erosion reached 3510 t in the same period. Result is the outcome of research project 2012/05/B/ST10/00309 of the National Science Centre (Poland).

Perceived and measured levels of environmental pollution: interdisciplinary research in the subarctic lowlands of northeast European Russia.

PubMed

Walker, Tony R; Habeck, Joachim Otto; Karjalainen, Timo P; Virtanen, Tarmo; Solovieva, Nadia; Jones, Viv; Kuhry, Peter; Ponomarev, Vasily I; Mikkola, Kari; Nikula, Ari; Patova, Elena; Crittenden, Peter D; Young, Scott D; Ingold, Tim

2006-08-01

Using interdisciplinary field research in the Usa Basin, northeast European Russia, we compared local inhabitants' perception of environmental problems with chemical and remote-sensing signatures of environmental pollution and their local impacts. Extensive coal mining since the 1930s around Inta and Vorkuta has left a legacy of pollution, detected by measuring snowpack, topsoil, and lichen chemistry, together with remote-sensing techniques and analysis of lake water and sediments. Vorkuta and its environs suffered the worst impacts, with significant metal loading and alkalization in lakes and topsoils, elevated metals and cations in terricolous (reindeer) lichens, and changes in vegetation communities. Although the coal industry has declined recently, the area boasts a booming oil and gas industry, based around Usinsk. Local perceptions and concerns of environmental pollution and protection were higher in Usinsk, as a result of increased awareness after a major oil spill in 1994, compared with Vorkuta's inhabitants, who perceived air pollution as the primary environmental threat. Our studies indicate that the principal sources of atmospheric emissions and local deposition within 25 to 40 km of Vorkuta were coal combustion from power and heating plants, coal mines, and a cement factory. Local people evaluated air pollution from direct observations and personal experiences, such as discoloration of snow and respiratory problems, whereas scientific knowledge played a minor role in shaping these perceptions.

Incorporation of Environmental Features in Flood Control Channel Projects.

DTIC Science & Technology

1985-05-01

compacted subgrades, a layer of gravel or slag , and a 2- to 4-in. layer of concrete or asphalt. An innovative *. grassed-bituminous trail consisting of 6 in...of slag or crushed stone over a compacted subgrade was proposed for Chartiers Creek (Figure 66). 6" BLACK SLAG OR CRUSHED STONE. PENETRATE - WITH...ASPHALT EMULSION. CHOKE WITH 28 SLAG . BROOM THOROUGHLY INTO VOIDS - A MIXTURE OF ONE HALF (1/2) TOPSOIL AND ONE HALF (1/2) IB BLACK SLAG , AND SEED

Installation Restoration Program Phase 2. Confirmation/Quantification. Stage 1. Volume 1.

DTIC Science & Technology

1986-10-10

FIGUR 1- EEA LNO EFIG I AiNLanfl GUARD BASESHOWING PHSE II INVTIGTOIE I 1- ........ Site No. - I MAA Site No.Northwest Landfill TS Site.No.4 West...Protective Steel PVC Cap Flush Mount in Casing Plastic Nelson Valve Box Land Surface PVC Cap . Cement Grout 0 L n aBentonite Pellet 4" Diameter Seal...12.0 feet BLS. Clays of high plasticity predominate in all three wells. No sand lenses were encountered and the topsoil at all three well locations is

Streamlined Archaeo-geophysical Data Processing and Integration for DoD Field Use

DTIC Science & Technology

2012-04-01

names can now be renamed and are, by default, named B1, B2, etc. It is hard to tell if Band buttons (B1, B2, etc.) are depressed or not. Contrast...consisted of a man-made depression surrounded by low ridges. That aspect of the fort’s layout is discussed further in Chapter 5. 4.1.5 SITE HISTORY...larger rocks, natural depressions representing concentrations of relatively magnetic topsoil, etc., (Bevan 1998). Pits are a common feature type, but

The effect of short-range spatial variability on soil sampling uncertainty.

PubMed

Van der Perk, Marcel; de Zorzi, Paolo; Barbizzi, Sabrina; Belli, Maria; Fajgelj, Ales; Sansone, Umberto; Jeran, Zvonka; Jaćimović, Radojko

2008-11-01

This paper aims to quantify the soil sampling uncertainty arising from the short-range spatial variability of elemental concentrations in the topsoils of agricultural, semi-natural, and contaminated environments. For the agricultural site, the relative standard sampling uncertainty ranges between 1% and 5.5%. For the semi-natural area, the sampling uncertainties are 2-4 times larger than in the agricultural area. The contaminated site exhibited significant short-range spatial variability in elemental composition, which resulted in sampling uncertainties of 20-30%.

Omo River Delta, Lake Turkana, Ethiopia/Kenya border, Africa

NASA Technical Reports Server (NTRS)

1991-01-01

As a result of land clearing operations in the local area, the Omo River Delta (4.5N, 36.0E) at the north end of Lake Turkana, on the Ethiopia/Kenya border has become enlarged through topsoil erosion. The delta measured 800 sq. km. in 1981 doubled to 1,600 sq. km. by 1988 and was up to 1,800 sq. km. in 1991. This is the same area where the Leaky Anthropological Team discovered the earliest remains of human ancestors.

Revegetation Study of Adobe Dam, Phoenix, Arizona. Task 5 and 7. Seeding Success on Topsoiled and Nontopsoiled Slopes at Adobe Dam.

DTIC Science & Technology

1983-08-18

cations (ammonium acetate procedure) and exchangable amonium -nitrogen (Black 1965). Nitrate -nitrogen was determined by potassium chloride extraction and...Justification Duncan T. Patten By and Distrib-_t i cn/ Avai1"il lit- Codes Timothy L. Righetti lAvn. il/or D Dist ]Special I Center for Environmental...seeded earlier. Significant vegetation-soil correlations demonstrated relationships of species densities and both nitrate -nitrogen and total nitrogen

Modeling short-term concentration fluctuations of semi-volatile pollutants in the soil-plant-atmosphere system.

PubMed

Bao, Zhongwen; Haberer, Christina M; Maier, Uli; Beckingham, Barbara; Amos, Richard T; Grathwohl, Peter

2016-11-01

Temperature changes can drive cycling of semi-volatile pollutants between different environmental compartments (e.g. atmosphere, soil, plants). To evaluate the impact of daily temperature changes on atmospheric concentration fluctuations we employed a physically based model coupling soil, plants and the atmosphere, which accounts for heat transport, effective gas diffusion, sorption and biodegradation in the soil as well as eddy diffusion and photochemical oxidation in the atmospheric boundary layer of varying heights. The model results suggest that temperature-driven re-volatilization and uptake in soils cannot fully explain significant diurnal concentration fluctuations of atmospheric pollutants as for example observed for polychlorinated biphenyls (PCBs). This holds even for relatively low water contents (high gas diffusivity) and high sorption capacity of the topsoil (high organic carbon content and high pollutant concentration in the topsoil). Observed concentration fluctuations, however, can be easily matched if a rapidly-exchanging environmental compartment, such as a plant layer, is introduced. At elevated temperatures, plants release organic pollutants, which are rapidly distributed in the atmosphere by eddy diffusion. For photosensitive compounds, e.g. some polycyclic aromatic hydrocarbons (PAHs), decreasing atmospheric concentrations would be expected during daytime for the bare soil scenario. This decline is buffered by a plant layer, which acts as a ground-level reservoir. The modeling results emphasize the importance of a rapidly-exchanging compartment above ground to explain short-term atmospheric concentration fluctuations. Copyright © 2016 Elsevier B.V. All rights reserved.

Remediation of grey forest soils heavily polluted with heavy metals by means of their leaching at acidic pH followed by the soil reclamation by means of neutralization and bacterial manure addition

NASA Astrophysics Data System (ADS)

Georgiev, Plamen; Groudev, Stoyan; Spasova, Irena; Nicolova, Marina

2014-05-01

Some grey forest soils in Western Bulgaria are heavily polluted with heavy metals (copper, lead, and zinc), arsenic, and uranium due to the infiltration of acid mine drainage generated at the abandoned uranium mine Curilo. This paper presents some results from a study about soil remediation based on the contaminants leaching from the topsoil by means of irrigation with solutions containing sulphuric acid or its in situ generation by means of sulphur-oxidizing chemolithotrophic bacteria in or without the presence of finely cut straw. These methods were tested in large scale zero suction lysimeters. The approaches based on S° and finely cut straw addition was the most efficient amongst the tested methods and for seven months of soil remediation the concentration of all soil contaminants were decreased below the relevant Maximum Admissible Concentration (MAC). Neutralization of the soil acidity was applied as a next stage of soil reclamation by adding CaCO3 and cow manure. As a result, soil pH increased from strongly acidic (2.36) to slightly acidic (6.15) which allowed subsequent addition of humic acids and bacterial manure to the topsoil. The soil habitat changed in this way facilitated the growth of microorganisms which restored the biogeochemical cycles of nitrogen and carbon to the levels typical for non-polluted grey forest soil.

Reclamation of cadmium-contaminated soil using dissolved organic matter solution originating from wine-processing waste sludge.

PubMed

Liu, Cheng-Chung; Chen, Guan-Bu

2013-01-15

Soil washing using an acid solution is a common practice for removing heavy metals from contaminated soil in Taiwan. However, serious loss of nutrients from soil is a major drawback of the washing. Distillery sludge can be used to prepare a dissolved organic matter (DOM) solution by extracting its organic constituents with alkaline solutions. This study employed DOM solutions to remediate Cd-contaminated soil (with concentrations up to 21.5 mg kg(-1)) and determine the factors affecting removal of Cd, such as pH, initial concentration of DOM solution, temperature, and washing frequency. When washing with pH 3.0 and 1250 mg L(-1) DOM solution, about 80% and 81% of Cd were removed from the topsoil at 27 °C and subsoil at 40 °C, respectively. To summarize the changes in fertility during DOM washing with various pH solutions: the increase in organic matter content ranged from 7.7% to 23.7%; cation exchange capacity (CEC) ranged from 4.6% to 13.9%; available ammonium (NNH(4)) content ranged from 39.4% to 2175%; and available phosphorus content ranged from 34.5% to 182%. Exchangeable K, Ca, and Mg remained in the topsoil after DOM washing, with concentrations of 1.1, 2.4, and 1.5 times higher than those treated with HCl solution at the same pH, respectively. Copyright © 2012 Elsevier B.V. All rights reserved.

Contamination of Phthalate Esters (PAEs) in Typical Wastewater-Irrigated Agricultural Soils in Hebei, North China.

PubMed

Zhang, Yuan; Liang, Qiong; Gao, Rutai; Hou, Haobo; Tan, Wenbing; He, Xiaosong; Zhang, Hui; Yu, Minda; Ma, Lina; Xi, Beidou; Wang, Xiaowei

2015-01-01

The Wangyang River (WYR) basin is a typical wastewater irrigation area in Hebei Province, North China. This study investigated the concentration and distribution of six priority phthalate esters (PAEs) in the agricultural soils in this area. Thirty-nine soil samples (0-20 cm) were collected along the WYR to assess the PAE residues in soils. Results showed that PAEs are ubiquitous environmental contaminants in the topsoil obtained from the irrigation area. The concentrations of Σ6PAEs range from 0.191 μg g-1 dw to 0.457 μg g-1 dw with an average value of 0.294 μg g-1 dw. Di(2-ethylhexyl) phthalate (DEHP) and di-n-butyl phthalate (DnBP) are the dominant PAE species in the agricultural soils. Among the DEHP concentrations, the highest DEHP concentration was found at the sites close to the villages; this result suggested that dense anthropogenic activities and random garbage disposal in the rural area are possible sources of PAEs. The PAE concentrations were weakly and positively correlated with soil organic carbon and soil enzyme activities; thus, these factors can affect the distribution of PAEs. This study further showed that only dimethyl phthalate (DMP) concentrations exceeded the recommended allowable concentrations; no remediation measures are necessary to control the PAEs in the WYR area. However, the PAEs in the topsoil may pose a potential risk to the ecosystem and human health in this area. Therefore, the exacerbating PAE pollution should be addressed.

Assessment of atmospheric deposition of heavy metals and other elements in Belgrade using the moss biomonitoring technique and neutron activation analysis.

PubMed

Anicić, Mira; Frontasyeva, Marina V; Tomasević, Milica; Popović, Aleksandar

2007-06-01

This study aimed at assessing atmospheric deposition of heavy metals and other elements using the moss genera Brachythecium sp. (B. rutabulum and B. salebrosum) and Eurhynchium sp. (E. hians and E. striatum) collected in autumn 2004 in the urban area of Belgrade. The concentrations of 36 elements (Na, Mg, Al, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, As, Se, Br, Rb, Sr, Mo, Sb, I, Cs, Ba, La, Ce, Sm, Tb, Dy, Hf, Ta, W, Hg, Th, U) were determined in moss and local topsoil samples by instrumental neutron activation analysis. The concentration of elements in moss positively correlated to those obtained for topsoil. High enrichment factors for As, Zn, Mo, Br, Sb, Se, Hg and Cl, calculated to continental crust composition, gave an evidence for anthropogenic impact on urban area, mainly due to intensive vehicular traffic and fossil fuel combustion. The concentration of elements in moss, characteristic for fossil fuel combustion, obtained in this study were substantially lower than in the previous investigation (2000) conducted in the area of Belgrade. The level of concentrations for V, Cr, Ni, and As in moss from this study correlated to those measured for neighboring countries, and were several times higher than the base-level data from low polluted areas. The level of accumulated elements in both investigated moss genera were similar and all studied species could be combined for biomonitoring purposes in urban areas.

Soil moisture and texture primarily control the soil nutrient stoichiometry across the Tibetan grassland.

PubMed

Tian, Liming; Zhao, Lin; Wu, Xiaodong; Fang, Hongbing; Zhao, Yonghua; Hu, Guojie; Yue, Guangyang; Sheng, Yu; Wu, Jichun; Chen, Ji; Wang, Zhiwei; Li, Wangping; Zou, Defu; Ping, Chien-Lu; Shang, Wen; Zhao, Yuguo; Zhang, Ganlin

2018-05-01

Soil nutrient stoichiometry and its environmental controllers play vital roles in understanding soil-plant interaction and nutrient cycling under a changing environment, while they remain poorly understood in alpine grassland due to lack of systematic field investigations. We examined the patterns and controls of soil nutrients stoichiometry for the top 10cm soils across the Tibetan ecosystems. Soil nutrient stoichiometry varied substantially among vegetation types. Alpine swamp meadow had larger topsoil C:N, C:P, N:P, and C:K ratios compared to the alpine meadow, alpine steppe, and alpine desert. In addition, the presence or absence of permafrost did not significantly impact soil nutrient stoichiometry in Tibetan grassland. Moreover, clay and silt contents explained approximately 32.5% of the total variation in soil C:N ratio. Climate, topography, soil properties, and vegetation combined to explain 10.3-13.2% for the stoichiometry of soil C:P, N:P, and C:K. Furthermore, soil C and N were weakly related to P and K in alpine grassland. These results indicated that the nutrient limitation in alpine ecosystem might shifts from N-limited to P-limited or K-limited due to the increase of N deposition and decrease of soil P and K contents under the changing climate conditions and weathering stages. Finally, we suggested that soil moisture and mud content could be good predictors of topsoil nutrient stoichiometry in Tibetan grassland. Copyright © 2017 Elsevier B.V. All rights reserved.

Environmental implications of high metal content in soils of a titanium mining zone in Kenya.

PubMed

Maina, David M; Ndirangu, Douglas M; Mangala, Michael M; Boman, Johan; Shepherd, Keith; Gatari, Michael J

2016-11-01

Mining activities contribute to an increase of specific metal contaminants in soils. This may adversely affect plant life and consequently impact on animal and human health. The objective of this study was to obtain the background metal concentrations in soils around the titanium mining in Kwale County for monitoring its environmental impacts. Forty samples were obtained with half from topsoils and the other from subsoils. X-ray fluorescence spectrometry was used to determine the metal content of the soil samples. High concentrations of Ti, Mn, Fe, and Zr were observed where Ti concentrations ranged from 0.47 to 2.8 %; Mn 0.02 to 3.1 %; Fe 0.89 to 3.1 %; and Zr 0.05 to 0.85 %. Using ratios of elemental concentrations in topsoil to subsoil method and enrichment factors concept, the metals were observed to be of geogenic origin with no anthropogenic input. The high concentrations of Mn and Fe may increase their concentration levels in the surrounding agricultural lands through deposition, thereby causing contamination on the land and the cultivated food crops. The latter can cause adverse human health effects. In addition, titanium mining will produce tailings containing low-level titanium concentrations, which will require proper disposal to avoid increasing titanium concentrations in the soils of the region since it has been observed to be phytotoxic to plants at high concentrations. The results of this study will serve as reference while monitoring the environmental impact by the titanium mining activities.

Spatial Distribution, Sources Apportionment and Health Risk of Metals in Topsoil in Beijing, China.

PubMed

Sun, Chunyuan; Zhao, Wenji; Zhang, Qianzhong; Yu, Xue; Zheng, Xiaoxia; Zhao, Jiayin; Lv, Ming

2016-07-20

In order to acquire the pollution feature and regularities of distribution of metals in the topsoil within the sixth ring road in Beijing, a total of 46 soil samples were collected, and the concentrations of twelve elements (Nickel, Ni, Lithium, Li, Vanadium, V, Cobalt, Co, Barium, Ba, Strontium, Sr, Chrome, Cr, Molybdenum, Mo, Copper, Cu, Cadmium, Cd, Zinc, Zn, Lead, Pb) were analyzed. Geostatistics and multivariate statistics were conducted to identify spatial distribution characteristics and sources. In addition, the health risk of the analyzed heavy metals to humans (adult) was evaluated by an U.S. Environmental Protection Agency health risk assessment model. The results indicate that these metals have notable variation in spatial scale. The concentration of Cr was high in the west and low in the east, while that of Mo was high in the north and low in the south. High concentrations of Cu, Cd, Zn, and Pb were found in the central part of the city. The average enrichment degree of Cd is 5.94, reaching the standard of significant enrichment. The accumulation of Cr, Mo, Cu, Cd, Zn, and Pb is influenced by anthropogenic activity, including vehicle exhaustion, coal burning, and industrial processes. Health risk assessment shows that both non-carcinogenic and carcinogenic risks of selected heavy metals are within the safety standard and the rank of the carcinogenic risk of the four heavy metals is Cr > Co > Ni > Cd.

Spatial Distribution, Sources Apportionment and Health Risk of Metals in Topsoil in Beijing, China

PubMed Central

Sun, Chunyuan; Zhao, Wenji; Zhang, Qianzhong; Yu, Xue; Zheng, Xiaoxia; Zhao, Jiayin; Lv, Ming

2016-01-01

In order to acquire the pollution feature and regularities of distribution of metals in the topsoil within the sixth ring road in Beijing, a total of 46 soil samples were collected, and the concentrations of twelve elements (Nickel, Ni, Lithium, Li, Vanadium, V, Cobalt, Co, Barium, Ba, Strontium, Sr, Chrome, Cr, Molybdenum, Mo, Copper, Cu, Cadmium, Cd, Zinc, Zn, Lead, Pb) were analyzed. Geostatistics and multivariate statistics were conducted to identify spatial distribution characteristics and sources. In addition, the health risk of the analyzed heavy metals to humans (adult) was evaluated by an U.S. Environmental Protection Agency health risk assessment model. The results indicate that these metals have notable variation in spatial scale. The concentration of Cr was high in the west and low in the east, while that of Mo was high in the north and low in the south. High concentrations of Cu, Cd, Zn, and Pb were found in the central part of the city. The average enrichment degree of Cd is 5.94, reaching the standard of significant enrichment. The accumulation of Cr, Mo, Cu, Cd, Zn, and Pb is influenced by anthropogenic activity, including vehicle exhaustion, coal burning, and industrial processes. Health risk assessment shows that both non-carcinogenic and carcinogenic risks of selected heavy metals are within the safety standard and the rank of the carcinogenic risk of the four heavy metals is Cr > Co > Ni > Cd. PMID:27447657

Comparison of different models for predicting soil bulk density. Case study - Slovakian agricultural soils

NASA Astrophysics Data System (ADS)

Makovníková, Jarmila; Širáň, Miloš; Houšková, Beata; Pálka, Boris; Jones, Arwyn

2017-10-01

Soil bulk density is one of the main direct indicators of soil health, and is an important aspect of models for determining agroecosystem services potential. By way of applying multi-regression methods, we have created a distributed prediction of soil bulk density used subsequently for topsoil carbon stock estimation. The soil data used for this study were from the Slovakian partial monitoring system-soil database. In our work, two models of soil bulk density in an equilibrium state, with different combinations of input parameters (soil particle size distribution and soil organic carbon content in %), have been created, and subsequently validated using a data set from 15 principal sampling sites of Slovakian partial monitoring system-soil, that were different from those used to generate the bulk density equations. We have made a comparison of measured bulk density data and data calculated by the pedotransfer equations against soil bulk density calculated according to equations recommended by Joint Research Centre Sustainable Resources for Europe. The differences between measured soil bulk density and the model values vary from -0.144 to 0.135 g cm-3 in the verification data set. Furthermore, all models based on pedotransfer functions give moderately lower values. The soil bulk density model was then applied to generate a first approximation of soil bulk density map for Slovakia using texture information from 17 523 sampling sites, and was subsequently utilised for topsoil organic carbon estimation.

Utilizing of magnetic parameters for evaluation of soil erosion rates on two different agricultural sites

NASA Astrophysics Data System (ADS)

Kapicka, A.; Grison, H.; Petrovsky, E.; Jaksik, O.; Kodesova, R.

2015-12-01

Field measurements of magnetic susceptibility were carried out on regular grid, resulting in 101 data points at Brumovice and 65 at Vidim locality. Mass specific magnetic susceptibility χ and its frequency dependence χFD was used to estimate the significance of SP ferrimagnetic particles of pedogenic origin in topsoil horizons. The lowest magnetic susceptibility was obtained on the steep valley sides. Here the original topsoil was eroded and mixed by tillage with the soil substrate (loess). Soil profiles unaffected by erosion were investigated in detail. The vertical distribution of magnetic susceptibility along these "virgin" profiles was measured in laboratory on samples collected with 2-cm spacing. The differences between the distribution of susceptibility in the undisturbed soil profiles and the magnetic signal after uniform mixing of the soil material as a result of erosion and tillage are fundamental for the estimation of soil loss in the studied test fields. Maximum cumulative soil erosion depth in Brumovice and Vidim is around 100 cm and 50 cm respectively. The magnetic method is suitable for mapping at the chernozem localities and measurement of soil magnetic susceptibility is in this case useful and fast technique for quantitative estimation of soil loss caused by erosion. However, it is less suitable (due to lower magnetic differentiation with depth) in areas with luvisol as dominant soil unit. Acknowledgement: This study was supported by NAZV Agency of the Ministry of Agriculture of the Czech Republic through grant No QJ1230319.

Acid-Tolerant Moderately Thermophilic Methanotrophs of the Class Gammaproteobacteria Isolated From Tropical Topsoil with Methane Seeps

PubMed Central

Islam, Tajul; Torsvik, Vigdis; Larsen, Øivind; Bodrossy, Levente; Øvreås, Lise; Birkeland, Nils-Kåre

2016-01-01

Terrestrial tropical methane seep habitats are important ecosystems in the methane cycle. Methane oxidizing bacteria play a key role in these ecosystems as they reduce methane emissions to the atmosphere. Here, we describe the isolation and initial characterization of two novel moderately thermophilic and acid-tolerant obligate methanotrophs, assigned BFH1 and BFH2 recovered from a tropical methane seep topsoil habitat. The new isolates were strictly aerobic, non-motile, coccus-shaped and utilized methane and methanol as sole carbon and energy source. Isolates grew at pH range 4.2–7.5 (optimal 5.5–6.0) and at a temperature range of 30–60°C (optimal 51–55°C). 16S rRNA gene phylogeny placed them in a well-separated branch forming a cluster together with the genus Methylocaldum as the closest relatives (93.1–94.1% sequence similarity). The genes pmoA, mxaF, and cbbL were detected, but mmoX was absent. Strains BFH1 and BFH2 are, to our knowledge, the first isolated acid-tolerant moderately thermophilic methane oxidizers of the class Gammaproteobacteria. Each strain probably denotes a novel species and they most likely represent a novel genus within the family Methylococcaceae of type I methanotrophs. Furthermore, the isolates increase our knowledge of acid-tolerant aerobic methanotrophs and signify a previously unrecognized biological methane sink in tropical ecosystems. PMID:27379029

Links between soil properties and steady-state solute transport through cultivated topsoil at the field scale

NASA Astrophysics Data System (ADS)

Koestel, J. K.; Norgaard, T.; Luong, N. M.; Vendelboe, A. L.; Moldrup, P.; Jarvis, N. J.; Lamandé, M.; Iversen, B. V.; Wollesen de Jonge, L.

2013-02-01

It is known that solute transport through soil is heterogeneous at all spatial scales. However, little data are available to allow quantification of these heterogeneities at the field scale or larger. In this study, we investigated the spatial patterns of soil properties, hydrologic state variables, and tracer breakthrough curves (BTCs) at the field scale for the inert solute transport under a steady-state irrigation rate which produced near-saturated conditions. Sixty-five undisturbed soil columns approximately 20 cm in height and diameter were sampled from the loamy topsoil of an agricultural field site in Silstrup (Denmark) at a sampling distance of approximately 15 m (with a few exceptions), covering an area of approximately 1 ha (60 m × 165 m). For 64 of the 65 investigated soil columns, we observed BTC shapes indicating a strong preferential transport. The strength of preferential transport was positively correlated with the bulk density and the degree of water saturation. The latter suggests that preferential macropore transport was the dominating transport process. Increased bulk densities were presumably related with a decrease in near-saturated hydraulic conductivities and as a consequence to larger water saturation and the activation of larger macropores. Our study provides further evidence that it should be possible to estimate solute transport properties from soil properties such as soil texture or bulk density. We also demonstrated that estimation approaches established for the column scale have to be upscaled when applied to the field scale or larger.

Contamination of Phthalate Esters (PAEs) in Typical Wastewater-Irrigated Agricultural Soils in Hebei, North China

PubMed Central

Zhang, Yuan; Liang, Qiong; Gao, Rutai; Hou, Haobo; Tan, Wenbing; He, Xiaosong; Zhang, Hui; Yu, Minda; Ma, Lina; Xi, Beidou; Wang, Xiaowei

2015-01-01

The Wangyang River (WYR) basin is a typical wastewater irrigation area in Hebei Province, North China. This study investigated the concentration and distribution of six priority phthalate esters (PAEs) in the agricultural soils in this area. Thirty-nine soil samples (0–20 cm) were collected along the WYR to assess the PAE residues in soils. Results showed that PAEs are ubiquitous environmental contaminants in the topsoil obtained from the irrigation area. The concentrations of Σ6PAEs range from 0.191 μg g−1 dw to 0.457 μg g−1 dw with an average value of 0.294 μg g−1 dw. Di(2-ethylhexyl) phthalate (DEHP) and di-n-butyl phthalate (DnBP) are the dominant PAE species in the agricultural soils. Among the DEHP concentrations, the highest DEHP concentration was found at the sites close to the villages; this result suggested that dense anthropogenic activities and random garbage disposal in the rural area are possible sources of PAEs. The PAE concentrations were weakly and positively correlated with soil organic carbon and soil enzyme activities; thus, these factors can affect the distribution of PAEs. This study further showed that only dimethyl phthalate (DMP) concentrations exceeded the recommended allowable concentrations; no remediation measures are necessary to control the PAEs in the WYR area. However, the PAEs in the topsoil may pose a potential risk to the ecosystem and human health in this area. Therefore, the exacerbating PAE pollution should be addressed. PMID:26360905

Contributions of root and shoot derived-C to soil organic matter throughout an agricultural soil profile assessed by compound-specific 13C analysis

NASA Astrophysics Data System (ADS)

Mendez-Millan, Mercedes; Dignac, Marie-France; Rumpel, Cornelia; Rasse, Daniel P.; Derenne, Sylvie

2010-05-01

The turnover of soil organic matter (SOM) is generally studied in the topsoil horizons, where the highest concentrations of organic carbon (OC) are found. Subsoils, although containing lower amounts of organic carbon compared to topsoils, greatly contribute to the total carbon stocks within a soil profile. An increase in SOM aliphaticity was observed during SOM degradation, and also down the soil profile, suggesting that the stable pool of SOM is enriched in aliphatic structures. These alkyl-C structures might mainly derive from cutins and suberins, two biomacromolecules, which contain biomarkers specific for shoot and root plant biomass. The aim of this study was to use cutin and suberin structural units to follow the incorporation of plant biomass originating from roots and shoots throughout an agricultural soil profile. We measured the 13C natural abundance of root and shoot biomarkers in samples taken from 15 to 105 cm depth in a C3/C4 chronosequence. After 9 years of maize (C4) cropping, the distribution of root biomarkers (diacids) significantly changed and their concentration increased compared to the wheat (CC3) soil. The largest increase was observed at 60-75 cm where diacids reached up to 134 ?g/gOC compared to 23 ?g/gOC in the wheat soil. Higher inputs from maize root biomass are also suggested by an average 13C enrichment of the root markers in the maize compared to the wheat soil.

Local deposition of mercury in topsoils around coal-fired power plants: is it always true?

PubMed

Rodriguez Martin, José Antonio; Nanos, Nikos; Grigoratos, Theodoros; Carbonell, Gregoria; Samara, Constantini

2014-09-01

Mercury (Hg) is a toxic element that is emitted to the atmosphere through human activities, mainly fossil fuel combustion. Hg accumulations in soil are associated with atmospheric deposition, while coal-burning power plants remain the most important source of anthropogenic mercury emissions. In this study, we analyzed the Hg concentration in the topsoil of the Kozani-Ptolemais basin where four coal-fired power plants (4,065 MW) run to provide 50 % of electricity in Greece. The study aimed to investigate the extent of soil contamination by Hg using geostatistical techniques to evaluate the presumed Hg enrichment around the four power plants. Hg variability in agricultural soils was evaluated using 276 soil samples from 92 locations covering an area of 1,000 km(2). We were surprised to find a low Hg content in soil (range 1-59 μg kg(-1)) and 50 % of samples with a concentration lower than 6 μg kg(-1). The influence of mercury emissions from the four coal-fired power plants on soil was poor or virtually nil. We associate this effect with low Hg contents in the coal (1.5-24.5 μg kg(-1)) used in the combustion of these power plants (one of the most Hg-poor in the world). Despite anthropic activity in the area, we conclude that Hg content in the agricultural soils of the Kozani-Ptolemais basin is present in low concentrations.

Tracing source pollution in soils using cadmium and lead isotopes.

PubMed

Cloquet, C; Carignan, J; Libourel, G; Sterckeman, T; Perdrix, E

2006-04-15

Tracing the source of heavy metals in the environment is of key importance for our understanding of their pollution and natural cycles in the surface Earth reservoirs. Up to now, most exclusively Pb isotopes were used to effectively trace metal pollution sources in the environment. Here we report systematic variations of Cd isotope ratios measured in polluted topsoils surrounding a Pb-Zn refinery plant in northern France. Fractionated Cd was measured in soil samples surrounding the refinery, and this fractionation can be attributed to the refining processes. Despite the Cd isotopic ratios being precisely measured, the obtained uncertainties are still large compared to the total isotopic variation. Nevertheless, for the first time, Cd isotopically fractionated by industrial processes may be traced in the environment. On the same samples, Pb isotope systematics suggested that materials actually used by the refinery were not the major source of Pb in soils, probably because refined ore origins changed over the 100 years of operation. On the other hand, Cd isotopes and concentrations measured in topsoils allowed identification of three main origins (industrial dust and slag and agriculture), assuming that all Cd ores are not fractionated, as suggested by terrestrial rocks so far analyzed, and calculation of their relative contributions for each sampling point. Understanding that this refinery context was an ideal situation for such a study, our results lead to the possibility of tracing sources of anthropogenic Cd and better constrain mixing processes, fluxes, transport, and phasing out of industrial input in nature.

Application of 2D electrical resistivity imaging and cone penetration test (CPT) to assess the harzadous effect of near surface water on foundations in Lagos Nigeria

NASA Astrophysics Data System (ADS)

Adewoyin, O. O.; Joshua, E. O.; Akinyemi, M. L.; Omeje, M.; Joel, E. S.

2017-05-01

Adequate information on the condition of the subsurface is very important for site evaluation for engineering purposes. In this study two dimensional (2D) geoelectrical resistivity survey and cone penetration tests were conducted to study the hazardous effect of excess near surface water on the foundation of building in a reclaimed land located at Victoria Island area of Lagos State. The results of the inverted 2D geoelectrical resistivity data revealed three distinct geoelectrical layers characterized by low to moderate electrical resistivity of 2.23 and 129Ωm and 9.46 to 636Ωm respectively. The topsoil is characterized by wet sandy soil, which is underlain by sandy clay and banded at the below by a geologic formation of low resistivity which is suspected to be clay. The clay material may be responsible for the excess water retention observed in the area. The CPT method on the other hand revealed a geological formation of low resistance to penetration between 2-3 kg/cm2 from the topsoil to a depth of 7 m, which may be the effect of excess water in the near surface. This study revealed that the foundation of building may not be founded directly on the soil in any reclaimed land as this may result in collapse as a result of upward migration of water to the near surface.

Optimising post-mining soil conditions to maximise restoration success in a biodiverse semiarid environment

NASA Astrophysics Data System (ADS)

Muñoz-Rojas, Miriam; Erickson, Todd; Merritt, David; Dixon, Kingsley

2014-05-01

The original topsoil of mine degraded areas is frequently lost or damaged, which together with the absence of soil forming materials is a major constraint for seed germination and establishment in post-mining restoration. Thus, management of the available topsoil and the use of alternative growth media are critical to improve restoration areas disturbed through mining. Here we are developing laboratory and field trials to define the optimal range for physical and chemical properties of potentially suitable natural and 're-made' soil substrates and growth medium for 20 selected native plant species from the mining intensive Pilbara region of Western Australia. In this semiarid area, water is a limiting factor for seedling establishment, which is compounded by the lack of organic matter of post-disturbance soils. Therefore, particular attention is given to indicators of soil biological activity such as soil respiration, and hydrological soil properties such as water holding capacity, infiltration, hydraulic conductivity and soil water repellence. This research is part of a broader multi-study approach, the Restoration Seedbank Initiative project, a partnership between The University of Western Australia, BHP Billiton Iron Ore, and Kings Park and Botanic Garden to develop the science and underpinning knowledge to achieve biodiverse restoration in the Pilbara region, where land areas disturbed by mining exceed 40,000 ha. Achieving restoration success is critical as the Pilbara region is an ancient landscape with diverse geology and high levels of regional and local endemism in plants and animals.

[Effect of long-term fertilizing regime on soil microbial diversity and soil property].

PubMed

Li, Chenhua; Zhang, Caixia; Tang, Lisong; Xiong, Zhengqin; Wang, Baozhan; Jia, Zhongjun; Li, Yan

2014-03-04

To evaluate the effect of long-term fertilization on soil microbial community and soil chemical and physical properties. Using a high-throughput pyrosequencing technique, we studied microbial community in the 0-300 cm soil samples covering a 20-year field-experiment with different fertilization applications including inorganic fertilizer alone (N 300 kg/hm2, P2O5 150 kg/hm2 and K2O 60 kg/hm2) and inorganic fertilizer combined with straw (same application rate of N and P fertilizer combined with 5.4 t straw). Actinobacteria and alpha-proteobacteria were the predominant groups in the topsoil (0-20 cm). As the soil depth increased, the relative abundance of actinobacteria decreased whereas that of proteobacteria, especially gamma-proteobacteria and beta-proteobacteria increased and gradually became the dominant groups in the subsoil (20-300 cm). Long-term fertilizing applications significantly affected soil microbial communities throughout the soil profile, and increased the relative abundance of ammonia-oxidizing archaea at 0-40 cm depth. In addition, agriculture management, e. g. irrigation may be an important driving factor for the distribution of ammonia-oxidizing bacteria in soil profile. Total nitrogen and organic carbon contents were the most influential factors on microbial community in the topsoil and in the subsoil, respectively. Long-term fertilizer applications altered soil nutrient availability within the soil profile, which was likely to result in the different microbial community structure between the fertilizer treatments, especially for the subsoil.

Contamination of agricultural lands by polycyclic aromatic hydrocarbons (Tver region, Russia)

NASA Astrophysics Data System (ADS)

Zhidkin, Andrey; Koshovskii, Timur; Gennadiev, Alexander

2016-04-01

It is important to study sources and concentrations of polycyclic aromatic hydrocarbons (PAHs) in the agriculture soils within areas without intensive contaminations. Our studied object was soil and snow cover in the taiga zone (Tver region, Russia). A total of 52 surface (0-30 cm) and 31 subsurface (30-50 cm) soil samples, and 13 snow samples were collected in 35 soil pits, located in forest, crop and layland soils. Studied concentrations of the following 11 individual compounds: two-ring compounds (diphenyl and naphthalene homologues); three-ring compounds (fluorene, phenanthrene, anthracene); four-ring compounds (chrysene, pyrene, tetraphene); five-ring compounds (perylene, benzo[a]pyrene); and six-ring compounds (benzo[ghi]perylene). Analyses made by specrtofluorometry method at the temperature of liquid nitrogen. The total concentrations of all PAHs in soil samples ranged from 9 to 770 ng*g-1 with a median of 96 ng*g-1. The sum of high molecular weight PAHs was significantly lower than the sum of low molecular weight PAHs in the studied soils. The phenanthrene concentration was highest and ranged from 1.2 to 720 ng*g-1 (medium 72 ng*g-1). Compared PAHs reserves in snow cover (μg*m-2) with the reserves in topsoil layer (μg*m-2 in the upper 30 cm). Low molecular weight PAHs (fluorene, phenanthrene, diphenyl, naphthalene) reserves in snow was less than 20% from the reserves in the soil surface layer. High molecular weight PAHs (benzo[a]pyrene, chrysene, perylene, pyrene and tetraphene) reserves in snow was about 50-70% from the reserves in soil surface layer. High molecular weight PAHs (benzo[ghi]perylene and anthracene) reserves in snow was more than in topsoil. PAHs vertical distribution in soil profiles was statistically examined. The total concentration of all PAHs decreased with depth in all studied forest soils. In the arable soils was no significant trend in domination of PAHs total concentrations in the plowing and subsoil layers. The ratio of topsoil to subsoil concentrations of PAHs is different for differ congeners. Contents of phenanthrene and fluorene predominantly increase with the depth. Content of high molecular weight PAHs (benzo[a]pyrene, anthracene, tetraphene, perylene and pyrene) predominantly decreased with the depth. Other PAHs congeners have indistinct profile distributions in studied pits. Based on studied results PAHs divided to associations with different concentrations, sources and vertical distribution in soils: a) phenanthrene and fluorine; b) naphthalene, diphenyl; c) pyrene, benzo(a)pyrene, tetraphene, perylene, chrysene; d) anthracene and benzo(ghi)perylene. Research is funded by Russian Science Foundation (Project 14-27-00083).

Mineral weathering experiments to explore the effects of vegetation shifts in high mountain region (Wind River Range, Wyoming, USA)

NASA Astrophysics Data System (ADS)

Mavris, Christian; Furrer, Gerhard; Dahms, Dennis; Anderson, Suzanne P.; Blum, Alex; Goetze, Jens; Wells, Aaron; Egli, Markus

2015-04-01

Climate change influences the evolution of soil and landscape. With changing climate, both flora and fauna must adapt to new conditions. It is unknown in many respects to what extent soils will react to warming and vegetation change. The aim of this study was to identify possible consequences for soils in a dry-alpine region with respect to weathering of primary minerals and leaching of elements under expected warming climate conditions due to shifts in vegetation. To achieve this, a field empirical approach was used in combination with laboratory weathering experiments simulating several scenarios. Study sites located in Sinks Canyon and in Stough Basin of the Wind River Range, Wyoming, USA, encompass ecotones that consist of tundra, forest, or sagebrush (from moist to dry, with increasing temperature, respectively). All soils are developed on granitoid moraines. The mineralogy of the soils along the altitudinal sequence was analysed using cathodoluminescence and X-ray diffraction, and revealed clear mineral transformations: biotite and plagioclase were both weathered to smectite while plagioclase also weathered to kaolinite. Cooler, wetter, altitude-dependent conditions seemed to promote weathering of these primary minerals. To test the impact of soil solutions from different ecotones on mineral weathering, aqueous extracts from topsoils (A horizons) were reacted with subsoils (B horizons) in batch experiments. Aqueous extracts of topsoil samples were generated for all three ecotones, and these solutions were characterized. For the batch experiments, the topsoil extracts were reacted for 1800 hours with the subsoil samples of the same ecotone, or with the subsoil samples from higher altitude ecotones. Solutions collected periodically during the experiments were measured using ICP-OES and ion chromatography. Dissolved Ca, Mg and K were mainly controlled by the chemical weathering of oligoclase, K-feldspar and biotite. With increasing altitude (and consequently cooler and moister climate) the total concentrations of Ca, Mg and K in the aqueous extracts decreased, the relative ionic contribution by K decreased, while the ionic contribution by Ca increased. Thus, a shift in vegetation due to climate change seems to affect the ionic composition - but not the ionic load - of the soil solution. In the case of a shift from forest - to - sagebrush and tundra - to - forest or sagebrush, the relative contribution by K strongly increases at the expense of Ca. We hypothesize that K should play an important role in future biogeochemical cycles under the assumptions of climate warming and subsequent vegetation shifts to higher altitudes.

Effects of tractor loads and tyre pressures on soil compaction in Tunisia under different moisture conditions

NASA Astrophysics Data System (ADS)

Khemis, Chiheb; Abrougui, Khaoula; Ren, Lidong; Mutuku, Eunice Ann; Chehaibi, Sayed; Cornelis, Wim

2017-04-01

Vegetables in Tunisia demand frequent tractor traffic for soil tillage, cultural operations and phytosanitary treatment, resulting in soil compaction. This study evaluates the effects of four levels of compaction by using different loads and tyre pressures of tractors, i.e., load 1 (C1) = 1460 kg, load 2 (C2) = 3100 kg, tyre pressure 1 (C3) = 800 kg cm-2, tyre pressure 2 (C4) = 1500 kg cm-2 on the hydraulic and physical properties of a sandy loam (10% clay, 20% silt, 68% sand) under three natural moisture conditions H0, H1 (15 days later), H2 (30 days later). At H0 average water content between 0 and 30 cm depth varied from 0.04 to 0.06 kg kg-1, at H1 between 0.13 and 0.07 kg kg-1, and at H2 between 0.10 and 0.09 kg kg-1. Each test run was limited to one pass. Undisturbed soil cores were collected in the topsoil (0-10 cm), at 10-20 cm and in the subsoil (20-30 cm) below the trace of the wheel at sites in the Higher Institute of Agronomy of Chott Mariam, Sousse, Tunisia. Soil compaction level was determined by penetration resistance using a penetrologger. Porosity, bulk density and permeability were then determined to evaluate the impact of the four load/tyre pressure combinations at the three moisture conditions on soil compaction. Prior to the experiment (C0), bulk density was 1.4 Mg m-3. After the tractor pass, the highest degree of compaction was observed with tractor load C2 and tyre pressure C4 which significantly changed soil bulk density resulting in values of up to 1.71 Mg m-3 in the topsoil and compacted subsoil under H2, which is significantly above the critical value of 1.6 Mg m-3 for soils with clay content below 17.5%. The high degree of compaction significantly affected penetration resistance and porosity of both topsoil and subsoil layers accordingly. Permeability was significantly reduced as a result of the induced compaction. The results demonstrate that different degrees of soil compaction under different moisture levels could greatly influence hydraulic and physical properties in different ways. Even under relatively low water contents, i.e., below or near field capacity, substantial top and subsoil compaction was induced after one tractor pass.

Heavy metal content (Cd, Ni, Cr and Pb) in soil amendment with a low polluted biosolid

NASA Astrophysics Data System (ADS)

Gomez Lucas, Ignacio; Lag Brotons, Alfonso; Navarro-Pedreño, Jose; Belén Almendro-Candel, Maria; Jordán, Manuel M.; Bech, Jaume; Roca, Nuria

2016-04-01

The progressively higher water quality standards in Europe has led to the generation of large quantities of sewage sludge derived from wastewater treatment (Fytili and Zabaniotou 2008). Composting is an effective method to minimize these risks, as pathogens are biodegraded and heavy metals are stabilized as a result of organic matter transformations (Barker and Bryson 2002; Noble and Roberts 2004). Most of the studies about sewage sludge pollution are centred in medium and high polluted wastes. However, the aim of this study was to assess the effects on soil heavy metal content of a low polluted sewage sludge compost in order to identify an optimal application rate based in heavy metal concentration under a period of cultivation of a Mediterranean horticultural plant (Cynara carducnculus). The experiment was done between January to June: rainfall was 71 mm, the volume of water supplied every week was 10.5 mm, mean air temperatures was 14.2, 20.4 (maximum), and 9.2◦C (minimum). The soil was a clay-loam anthrosol (WRB 2006). The experimental plot (60 m2) was divided into five subplots with five treatments corresponding to 0, 2, 4, 6, and 8 kg compost/m2. Three top-soil (first 20 cm) samples from each treatment were taken (January, April and June) and these parameters were analysed: pH, electrical conductivity, organic matter and total content of heavy metals (microwave acid digestion followed by AAS-spectrometry determination). The results show that sewage sludge compost treatments increase the organic matter content and salinity (electrical conductivity of the soils) and diminish the pH. Cd and Ni total content in top-soil was affected and both slightly reduce their concentration. Pb and Cr show minor changes. In general, the application of this low polluted compost may affect the mobility of Cd and Ni due to the pH modification and the water added by irrigation along time but Pb and Cr remain their content in the top-soil. References Barker, A.V., and G.M. Bryson. 2002. "Bioremediation of Heavy Metals and Organic Toxicants by Composting." The Scientific World Journal 2: 407-420. Fytili, D., and A. Zabaniotou. 2008. "Utilization of Sewage Sludge in EU Application of Old and New Methods - A Review." Renewable and Sustainable Energy Reviews 12: 116-140. Noble, R., and S.J. Roberts. 2004. "Eradication of Plant Pathogens and Nematodes during composting: A Review." Plant Patology 53: 548-568.

Soil stability characteristics of mulberry lands at hydro-fluctuation belt in the Three Gorges Reservoir area, China.

PubMed

Jiang, Ping; Shi, Dongmei; Hu, Xueqin; Huang, Xianzhi; Li, Yexin; Guo, Tianlei

2015-10-01

The hydro-fluctuation belt in the Three Gorges Reservoir area is a typical seasonal and artificial wetland system and ecologically fragile zone. Using the widely existing mulberry forest lands in the hydro-fluctuation belt as an example and the 180-m water-level forest land as a control, this paper analyzes the soil stability of mulberry forestlands at different water levels in the hydro-fluctuation belt by analyzing and comparing the changes between soil physical and mechanical properties. The results indicated that (1) water-level changes, such as rising, flooding, draining, and exposure, affect the soil structure in mulberry forestlands. The soil agglomeration statuses for the soil layers decreased from 180 > 175 > 170 > 165 m, and the soil agglomeration statuses at a depth of 0∼20 cm decreased by 43.79, 44.95, and 57.45% compared with the control. (2) The soil water stability index decreased as follows: 180 > 170 > 175 > 165 m, which only accounted for 50.00, 47.73, and 40.91% of the control. In addition, the soil water stability indexes for the topsoils at various water levels were 1.87 (180 m), 1.67 (175 m), 2.92 (170 m), and 1.86 (165 m) times greater than those of the subsoils; thus, the resistance to hydraulic dispersion and disintegration were greater in the topsoil than in the subsoil. (3) The soil aggregate stability index decreased from 180 > 165 > 170 > 175 m and by 22.75, 23.53, and 35.29% compared with the control. (4) The soil shear strengths (composed of the cohesive force C and the internal friction angle φ) of the topsoils at water levels of 175, 170, and 165 m were significantly lower than in the control, and the internal friction angles decreased by 10.52, 19.08, and 43.25% and the cohesive force decreased by 9.88, 16.36, and 27.51%, respectively. The stability of the soil structure was greatly influenced by the soil clay content, soil organic matter content, and waterlogging duration. The study results could provide scientific support for soil and water conservation in the hydro-fluctuation belt and for biological filter construction in the Three Gorges Reservoir area to control the transport of sediment and non-point source pollutants.

Cretaceous Footprints Found on Goddard Campus

NASA Image and Video Library

2017-12-08

Goddard's consultant paleontologist Dr. Lee Monnens verified the track and discovered additional footprints hiding under a thin layer of topsoil in the same rock layer on October 23, 2012. Credit: NASA/Goddard/Rebecca Roth NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Comparison of organochlorine pesticides occurrence, origin, and character in agricultural and industrial soils in Beijing.

PubMed

Shi, Yajuan; Lu, Yonglong; Wang, Tieyu; Wang, Guang; Luo, Wei

2009-10-01

The origin and occurrence of organochlorine pesticides [OCPs; hexachlorocyclohexanes (HCHs) and 1,1,1-trichloro-2,2- bis(p-chlorophenyl) ethane (DDTs)] in the surface and profile of soils from former OCPs production areas were compared with those of agricultural plots in Beijing, China in order to identify their characteristics, assess the eco-toxicological risk, and provide management suggestions. The comparison indicated heavier contamination caused by the production, storage, and waste disposal than the application of OCPs. Concentrations of HCHs and DDTs in topsoils varied by several orders of magnitude among different land-use groups. The concentrations (ng/g dry soil, geometric means) of HCHs (1958.2) and DDTs (3998.2) in the topsoils of former OCPs production factories were significantly higher than those in agricultural soils. The residue of DDTs and HCHs accumulated only on the surface of agricultural soil, but at depths ranging from 0 to 400 cm for the OCPs plant and warehouse. beta-HCH and p,p'-DDE dominated in the agricultural soils, whereas beta-HCH, gamma-HCH, p,p'-DDT, and p,p'-DDE were dominant in the industrial soils. The risk of examined OCPs in soils on human health was assessed in light of the Dutch and Canadian soil quality criteria, and the results indicated a high risk in the OCPs production factory area and the agricultural lands with large application. The results point to the need for urgent actions to evaluate long-term toxicity and preassessment for OCPs-related land-use management.

Chemical restrictions of roots in Ultisol subsoils lessened by long-term management

NASA Technical Reports Server (NTRS)

Hardy, D. H.; Raper, C. D. Jr; Miner, G. S.; Raper CD, J. r. (Principal Investigator)

1990-01-01

Exchangeable Al in subsoils of Ultisols in the southeastern USA can restrict rooting depth. Downward movement of basic cations (Ca, Mg, and K), applied as lime and fertilizer, may diminish that restriction over time. Materials from the argillic horizon were collected from three paired sites, having managed (long-term cropping) and nonmanaged topsoils (Typic Paleudults and Hapludults). One managed site was cropped continuously for 15 yr while the others were cultivated for more than 30 yr. Concentrations of extractable cations and other nutrients from the paired sites were compared to determine the magnitude of change due to management. The ability of the subsoils to support plant growth was evaluated in a missing-nutrient greenhouse experiment with sorghum [Sorghum bicolor (L.) Moench]. Subsoils of managed sites had greater effective cation-exchange capacity (CEC) and base saturation than those of non-managed sites. While availabilities of Ca, Mg, and K in subsoils of nonmanaged sites were inadequate to support maximal plant growth, they were adequate in subsoils of managed sites. Compared with nonmanaged sites, KCl-exchangeable Al in subsoils of managed sites was 23% lower at the 15-yr location and 65 and 100% lower at the two other locations. In the absence of lime, sorghum growth was almost totally inhibited on nonmanaged subsoils amended with optimum nutrients. On the managed subsoils, where 100, 65, and 23% of the nonmanaged exchangeable Al had been neutralized by topsoil fertilization and liming, growth reductions under the same conditions were 0, 50, and 100%, respectively. Thus, relatively long-term management had improved these Ultisol subsoils for root growth and development.

Soil food web changes during spontaneous succession at post mining sites: a possible ecosystem engineering effect on food web organization?

PubMed

Frouz, Jan; Thébault, Elisa; Pižl, Václav; Adl, Sina; Cajthaml, Tomáš; Baldrián, Petr; Háněl, Ladislav; Starý, Josef; Tajovský, Karel; Materna, Jan; Nováková, Alena; de Ruiter, Peter C

2013-01-01

Parameters characterizing the structure of the decomposer food web, biomass of the soil microflora (bacteria and fungi) and soil micro-, meso- and macrofauna were studied at 14 non-reclaimed 1- 41-year-old post-mining sites near the town of Sokolov (Czech Republic). These observations on the decomposer food webs were compared with knowledge of vegetation and soil microstructure development from previous studies. The amount of carbon entering the food web increased with succession age in a similar way as the total amount of C in food web biomass and the number of functional groups in the food web. Connectance did not show any significant changes with succession age, however. In early stages of the succession, the bacterial channel dominated the food web. Later on, in shrub-dominated stands, the fungal channel took over. Even later, in the forest stage, the bacterial channel prevailed again. The best predictor of fungal bacterial ratio is thickness of fermentation layer. We argue that these changes correspond with changes in topsoil microstructure driven by a combination of plant organic matter input and engineering effects of earthworms. In early stages, soil is alkaline, and a discontinuous litter layer on the soil surface promotes bacterial biomass growth, so the bacterial food web channel can dominate. Litter accumulation on the soil surface supports the development of the fungal channel. In older stages, earthworms arrive, mix litter into the mineral soil and form an organo-mineral topsoil, which is beneficial for bacteria and enhances the bacterial food web channel.

Rate of hydrolysis and degradation of the cyanogenic glycoside - dhurrin - in soil.

PubMed

Johansen, Henrik; Rasmussen, Lars Holm; Olsen, Carl Erik; Bruun Hansen, Hans Christian

2007-02-01

Cyanogenic glycosides are common plant toxins. Toxic hydrogen cyanide originating from cyanogenic glycosides may affect soil processes and water quality. In this study, hydrolysis, degradation and sorption of dhurrin (4-hydroxymandelonitrile-beta-d-glucoside) produced by sorghum has been studied in order to assess its fate in soil. The log K(ow) of dhurrin was -1.18+/-0.08 (22 degrees C). Hydrolysis was a first-order reaction with respect to dhurrin and hydroxyl ion concentrations. Half lives ranged from 1.2h (pH 8.6; 25 degrees C) to 530d (pH 4; 25 degrees C). The activation energy of hydrolysis was 112+9kJ. At pH 5.8 and room temperature, addition of humic acids (50gl(-1)) increased the rate of hydrolysis tenfold, while addition of kaolinite or goethite (100-250gl(-1)) both decreased the rate considerably. No significant sorption to soil components could be observed. The degradation rates of dhurrin in top and subsoils of Oxisols, Ultisols, Alfisols and Mollisols were studied at 22 degrees C (25mgl(-1), soil:liquid 1:1 (w:V), pH 3.8-8.1). Half-lives were 0.25-2h for topsoils, and 5-288h in subsoils. Hydrolysis in solution explained up to 45% of the degradation in subsoils whereas the contribution in topsoils was less than 14%, indicating the importance of enzymatic degradation processes. The highest risk of dhurrin leaching will take place when the soil is a low activity acid shallow soil with low content of clay minerals, iron oxides and humic acids.

DOE Office of Scientific and Technical Information (OSTI.GOV)

McLaughlin, M.J.; Tiller, K.G.; Beech, T.A.

Elevated Cd concentrations have been observed in potato (Solanum tuberosum L.) tubers from commercial crops in certain regions of southern Australia. Reasons for enhanced Cd uptake by tubers were investigated by a survey of commercial crops and associated soils. Eighty-nine sites were selected and paired tuber and soil samples taken. Concentration of Cd in tubers was compared to potato variety, tuber elemental composition, and chemical-physical characteristics of topsoil (0-150) and subsoil (150-300 mm). Tuber Cd concentrations were positively related to soil electrical conductivity (EC) and extractable Cl (R{sup 2} = 0.62, P < 0.001) in the topsoil, with extractable Clmore » accounting for more variation than EC. Tuber Cd concentrations were not strongly related (R{sup 2} = 0.23, P < 0.05) to potato variety alone. However, inclusion of variety and EDTA-extractable Zn with water-extractable Cl in a multivariate model resulted in a small but significant improvement in the variance accounted for by the model (R{sup 2} = 0.73, p < 0.001). Tuber Cd was unrelated to tuber concentrations of P or tuber but was positively related to concentrations of major cations in the tuber particularly Na. Soil pH, total C, EDTA-extractable Cd, or particle-size distribution were not correlated to tuber Cd concentrations, either singly or after inclusion in a multivariate model with soil Cl concentrations. As Cl is known to mobilize soil Cd and increase its phytoavailability, elevated Cd concentrations in potato tubers in southern Australia appear to be largely a result of the use of saline irrigation waters. 41 refs., 5 figs., 4 tabs.« less

Phene Synergism between Root Hair Length and Basal Root Growth Angle for Phosphorus Acquisition1[OPEN

PubMed Central

Miguel, Magalhaes Amade

2015-01-01

Shallow basal root growth angle (BRGA) increases phosphorus acquisition efficiency by enhancing topsoil foraging because in most soils, phosphorus is concentrated in the topsoil. Root hair length and density (RHL/D) increase phosphorus acquisition by expanding the soil volume subject to phosphorus depletion through diffusion. We hypothesized that shallow BRGA and large RHL/D are synergetic for phosphorus acquisition, meaning that their combined effect is greater than the sum of their individual effects. To evaluate this hypothesis, phosphorus acquisition in the field in Mozambique was compared among recombinant inbred lines of common bean (Phaseolus vulgaris) having four distinct root phenotypes: long root hairs and shallow basal roots, long root hairs and deep basal roots, short root hairs and shallow basal roots, and short root hairs and deep basal roots. The results revealed substantial synergism between BRGA and RHL/D. Compared with short-haired, deep-rooted phenotypes, long root hairs increased shoot biomass under phosphorus stress by 89%, while shallow roots increased shoot biomass by 58%. Genotypes with both long root hairs and shallow roots had 298% greater biomass accumulation than short-haired, deep-rooted phenotypes. Therefore, the utility of shallow basal roots and long root hairs for phosphorus acquisition in combination is twice as large as their additive effects. We conclude that the anatomical phene of long, dense root hairs and the architectural phene of shallower basal root growth are synergetic for phosphorus acquisition. Phene synergism may be common in plant biology and can have substantial importance for plant fitness, as shown here. PMID:25699587

Soil Food Web Changes during Spontaneous Succession at Post Mining Sites: A Possible Ecosystem Engineering Effect on Food Web Organization?

PubMed Central

Frouz, Jan; Thébault, Elisa; Pižl, Václav; Adl, Sina; Cajthaml, Tomáš; Baldrián, Petr; Háněl, Ladislav; Starý, Josef; Tajovský, Karel; Materna, Jan; Nováková, Alena; de Ruiter, Peter C.

2013-01-01

Parameters characterizing the structure of the decomposer food web, biomass of the soil microflora (bacteria and fungi) and soil micro-, meso- and macrofauna were studied at 14 non-reclaimed 1– 41-year-old post-mining sites near the town of Sokolov (Czech Republic). These observations on the decomposer food webs were compared with knowledge of vegetation and soil microstructure development from previous studies. The amount of carbon entering the food web increased with succession age in a similar way as the total amount of C in food web biomass and the number of functional groups in the food web. Connectance did not show any significant changes with succession age, however. In early stages of the succession, the bacterial channel dominated the food web. Later on, in shrub-dominated stands, the fungal channel took over. Even later, in the forest stage, the bacterial channel prevailed again. The best predictor of fungal bacterial ratio is thickness of fermentation layer. We argue that these changes correspond with changes in topsoil microstructure driven by a combination of plant organic matter input and engineering effects of earthworms. In early stages, soil is alkaline, and a discontinuous litter layer on the soil surface promotes bacterial biomass growth, so the bacterial food web channel can dominate. Litter accumulation on the soil surface supports the development of the fungal channel. In older stages, earthworms arrive, mix litter into the mineral soil and form an organo-mineral topsoil, which is beneficial for bacteria and enhances the bacterial food web channel. PMID:24260281

Dust emission and soil loss due to anthropogenic activities by wind erosion simulations

NASA Astrophysics Data System (ADS)

Katra, Itzhak; Swet, Nitzan; Tanner, Smadar

2017-04-01

Wind erosion is major process of soil loss and air pollution by dust emission of clays, nutrients, and microorganisms. Many soils throughout the world are currently or potentially associated with dust emissions, especially in dryland zones. The research focuses on wind erosion in semi-arid soils (Northern Negev, Israel) that are subjected to increased human activities of urban development and agriculture. A boundary-layer wind tunnel has been used to study dust emission and soil loss by simulation and quantification of high-resolution wind processes. Field experiments were conducted in various surface types of dry loess soils. The experimental plots represent soils with long-term and short term influences of land uses such as agriculture (conventional and organic practices), grazing, and natural preserves. The wind tunnel was operated under various wind velocities that are above the threshold velocity of aeolian erosion. Total soil sediment and particulate matter (PM) fluxes were calculated. Topsoil samples from the experimental plots were analysed in the laboratory for physical and chemical characteristics including aggregation, organic matter, and high-resolution particle size distribution. The results showed variations in dust emission in response to surface types and winds to provide quantitative estimates of soil loss over time. Substantial loss of particulate matter that is < 10 micrometer in diameter, including clays and nutrients, was recorded in most experimental conditions. Integrative analyses of the topsoil properties and dust experiment highlight the significant implications for soil nutrient resources and management strategies as well as for PM loading to the atmosphere and air pollution.

Exposure to aged crumb rubber reduces survival time during a stress test in earthworms (Eisenia fetida).

PubMed

Pochron, Sharon; Nikakis, Jacqueline; Illuzzi, Kyra; Baatz, Andrea; Demirciyan, Loriana; Dhillon, Amritjot; Gaylor, Thomas; Manganaro, Alexa; Maritato, Nicholas; Moawad, Michael; Singh, Rajwinder; Tucker, Clara; Vaughan, Daniel

2018-04-01

Solid waste management struggles with the sustainable disposal of used tires. One solution involves shredding used tires into crumb rubber and using the material as infill for artificial turf. However, crumb rubber contains hydrocarbons, organic compounds, and heavy metals, and it travels into the environment. Earthworms living in soil contaminated with virgin crumb rubber gained 14% less body weight than did earthworms living in uncontaminated soil, but the impact of aged crumb rubber on the earthworms is unknown. Since many athletic fields contain aged crumb rubber, we compared the body weight, survivorship, and longevity in heat and light stress for earthworms living in clean topsoil to those living in topsoil contaminated with aged crumb rubber. We also characterized levels of metals, nutrients, and micronutrients of both soil treatments and compared those to published values for soil contaminated with virgin crumb rubber. Consistent with earlier research, we found that contaminated soil did not inhibit microbial respiration rates. Aged crumb rubber, like new crumb rubber, had high levels of zinc. However, while exposure to aged crumb rubber did not reduce earthworm body weight as did exposure to new crumb rubber, exposure to aged crumb rubber reduced earthworm survival time during a stress test by a statistically significant 38 min (16.2%) relative to the survival time for worms that had lived in clean soil. Aged crumb rubber and new crumb rubber appear to pose similar toxic risks to earthworms. This study suggests an environmental cost associated with the current tire-recycling solution.

Dealing with deep uncertainties in landslide modelling for disaster risk reduction under climate change

NASA Astrophysics Data System (ADS)

Almeida, Susana; Holcombe, Elizabeth Ann; Pianosi, Francesca; Wagener, Thorsten

2017-02-01

Landslides have large negative economic and societal impacts, including loss of life and damage to infrastructure. Slope stability assessment is a vital tool for landslide risk management, but high levels of uncertainty often challenge its usefulness. Uncertainties are associated with the numerical model used to assess slope stability and its parameters, with the data characterizing the geometric, geotechnic and hydrologic properties of the slope, and with hazard triggers (e.g. rainfall). Uncertainties associated with many of these factors are also likely to be exacerbated further by future climatic and socio-economic changes, such as increased urbanization and resultant land use change. In this study, we illustrate how numerical models can be used to explore the uncertain factors that influence potential future landslide hazard using a bottom-up strategy. Specifically, we link the Combined Hydrology And Stability Model (CHASM) with sensitivity analysis and Classification And Regression Trees (CART) to identify critical thresholds in slope properties and climatic (rainfall) drivers that lead to slope failure. We apply our approach to a slope in the Caribbean, an area that is naturally susceptible to landslides due to a combination of high rainfall rates, steep slopes, and highly weathered residual soils. For this particular slope, we find that uncertainties regarding some slope properties (namely thickness and effective cohesion of topsoil) are as important as the uncertainties related to future rainfall conditions. Furthermore, we show that 89 % of the expected behaviour of the studied slope can be characterized based on only two variables - the ratio of topsoil thickness to cohesion and the ratio of rainfall intensity to duration.

Leaching and degradation of corn and soybean pesticides in an Oxisol of the Brazilian Cerrados.

PubMed

Laabs, V; Amelung, W; Pinto, A; Altstaedt, A; Zech, W

2000-11-01

Pesticide pollution of ground and surface water is of growing concern in tropical countries. The objective of this pilot study was to evaluate the leaching potential of eight pesticides in a Brazilian Oxisol. In a field experiment near Cuiabá, Mato Grosso, atrazine, chlorpyrifos, lambda-cyhalothrin, endosulfane alpha, metolachlor, monocrotofos, simazine, and trifluraline were applied onto a Typic Haplustox. Dissipation in the topsoil, mobility within the soil profile and leaching of pesticides were studied for a period of 28 days after application. The dissipation half-life of pesticides in the topsoil ranged from 0.9 to 14 d for trifluraline and metolachlor, respectively. Dissipation curves were described by exponential functions for polar pesticides (atrazine, metolachlor, monocrotofos, simazine) and bi-exponential ones for apolar substances (chlorpyrifos, lambda-cyhalothrin, endosulfane alpha, trifluraline). Atrazine, simazine and metolachlor were moderately leached beyond 15 cm soil depth, whereas all other compounds remained within the top 15 cm of the soil. In lysimeter percolates (at 35 cm soil depth), 0.8-2.0% of the applied amounts of atrazine, simazine, and metolachlor were measured within 28 days after application. Of the other compounds less than 0.03% of the applied amounts was detected in the soil water percolates. The relative contamination potentials of pesticides, according to the lysimeter study, were ranked as follows: metolachlor > atrazine = simazine > monocrotofos > endsulfane alpha > chlorpyrifos > trifluraline > lambda-cyhalothrin. This order of the pesticides was also achieved by ranking them according to their effective sorption coefficient Ke, which is the ratio of Koc to field-dissipation half-life.

Chemical and microbiological characterization of an aged PCB-contaminated soil.

PubMed

Stella, T; Covino, S; Burianová, E; Filipová, A; Křesinová, Z; Voříšková, J; Větrovský, T; Baldrian, P; Cajthaml, T

2015-11-15

This study was aimed at complex characterization of three soil samples (bulk soil, topsoil and rhizosphere soil) from a site historically contaminated with polychlorinated biphenyls (PCB). The bulk soil was the most highly contaminated, with a PCB concentration of 705.95 mg kg(-1), while the rhizosphere soil was the least contaminated (169.36 mg kg(-1)). PCB degradation intermediates, namely chlorobenzoic acids (CBAs), were detected in all the soil samples, suggesting the occurrence of microbial transformation processes over time. The higher content of organic carbon in the topsoil and rhizosphere soil than in the bulk soil could be linked to the reduced bioaccessibility (bioavailability) of these chlorinated pollutants. However, different proportions of the PCB congener contents and different bioaccessibility of the PCB homologues indicate microbial biotransformation of the compounds. The higher content of organic carbon probably also promoted the growth of microorganisms, as revealed by phospholipid fatty acid (PFLA) quantification. Tag-encoded pyrosequencing analysis showed that the bacterial community structure was significantly similar among the three soils and was predominated by Proteobacteria (44-48%) in all cases. Moreover, analysis at lower taxonomic levels pointed to the presence of genera (Sphingomonas, Bulkholderia, Arthrobacter, Bacillus) including members with reported PCB removal abilities. The fungal community was mostly represented by Basidiomycota and Ascomycota, which accounted for >80% of all the sequences detected in the three soils. Fungal taxa with biodegradation potential (Paxillus, Cryptococcus, Phoma, Mortierella) were also found. These results highlight the potential of the indigenous consortia present at the site as a starting point for PCB bioremediation processes. Copyright © 2015 Elsevier B.V. All rights reserved.

Phytostabilization of a landfill containing coal combustion waste.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barton, Christopher; Marx, Donald; Adriano, Domy

2005-12-01

The establishment of a vegetative cover to enhance evapotranspiration and control runoff and drainage was examined as a method for stabilizing a landfill containing coal combustion waste. Suitable plant species and pretreatment techniques in the form of amendments, tilling, and chemical stabilization were evaluated. A randomized plot design consisting of three subsurface treatments (blocks) and five surface amendments (treatments) was implemented. The three blocks included (1) ripping and compost amended, (2) ripping only, and (3) control. Surface treatments included (1) topsoil, (2) fly ash, (3) compost, (4) apatite, and (5) control. Inoculated loblolly (Pinus taeda) and Virginia (Pinus virginiana) pinemore » trees were planted on each plot. After three growing seasons, certain treatments were shown to be favorable for the establishment of vegetation on the basin. Seedlings located on block A developed a rooting system that penetrated into the basin media without significant adverse effects to the plant. However, seedlings on blocks B and C displayed poor rooting conditions and high mortality, regardless of surface treatment. Pore-water samples from lysimeters in block C were characterized by high acidity, Fe, Mn, Al, sulfate, and traceelement concentrations. Water-quality characteristics of the topsoil plots in block A, however, conformed to regulatory protocols. A decrease in soil-moisture content was observed in the rooting zone of plots that were successfully revegetated, which suggests that the trees, in combination with the surface treatments, influenced the water balance by facilitating water loss through transpiration and thereby reducing the likelihood of unwanted surface runoff and/or drainage effluent.« less

Dredged Illinois River Sediments: Plant Growth and Metal Uptake

USGS Publications Warehouse

Darmody, R.G.; Marlin, J.C.; Talbott, J.; Green, R.A.; Brewer, E.F.; Stohr, C.

2004-01-01

Sedimentation of the Illinois River in central Illinois has greatly diminished the utility and ecological value of the Peoria Lakes reach of the river. Consequently, a large dredging project has been proposed to improve its wildlife habitat and recreation potential, but disposal of the dredged sediment presents a challenge. Land placement is an attractive option. Previous work in Illinois has demonstrated that sediments are potentially capable of supporting agronomic crops due to their high natural fertility and water holding capacity. However, Illinois River sediments have elevated levels of heavy metals, which may be important if they are used as garden or agricultural soil. A greenhouse experiment was conducted to determine if these sediments could serve as a plant growth medium. A secondary objective was to determine if plants grown on sediments accumulated significant heavy metal concentrations. Our results indicated that lettuce (Lactuca sativa L.), barley (Hordeum vulgare L.), radish (Raphanus sativus L.), tomato (Lycopersicon lycopersicum L.), and snap bean (Phaseolus vulagaris L. var. humillis) grown in sediment and a reference topsoil did not show significant or consistent differences in germination or yields. In addition, there was not a consistent statistically significant difference in metal content among tomatoes grown in sediments, topsoil, or grown locally in gardens. In the other plants grown on sediments, while Cd and Cu in all cases and As in lettuce and snap bean were elevated, levels were below those considered excessive. Results indicate that properly managed, these relatively uncontaminated calcareous sediments can make productive soils and that metal uptake of plants grown in these sediments is generally not a concern.

Effect of soil nursery mixtures and hormone on the growth of Tetrastigma rafflesiae (Miq.) planch

NASA Astrophysics Data System (ADS)

Arshad, Syamsurina; Talip, Noraini; Adam, Jumaat

2018-04-01

Tetrastigma rafflesiae (Miq.) Planch is one of the sole host species of parasitic plants in the family Rafflesiaceae. A study was conducted in order to propagate this species using vegetative propagation. This propagation technique was done using stem cuttings and was conducted in the nursery at the National University of Malaysia (UKM). The propagation medium were made using four types of soil nursery mixtures of topsoil, organic matter and sand (7:3:1, 3:2:1, 2:1:1 and 1:1:1), mixture of topsoil, organic matter, sand and three different hormones treatments (0:0:IAA, 0:0:IBA and 0:0:NAA) and without any hormone treatment in basic soil (1:0:0, 0:1:0 and 0:0:1) was treated as a control. Approximately, stem cutting was used in 15 cm length. The base of each cutting was treated with root powdered hormones before being planted in soil. After 180 days of planting, the high number of leaf quantity (>12 leaves) was produced from stem cutting planted in 3:2:1 soil mixtures and the same results was obtained from stem cutting more than 15 cm to 18.78 cm in length, significantly. Soil mixture with 7:3:1 has significantly increased the leaf chlorophyll contents (10.22 nm) and also increased in leaf area index (16.375 cm²). Treatment hormones do not have any significant result in this study. The study has showed that T. rafflesiae can be propagated using cuttings as alternative source of planting materials for conservation purposes.

Evaluation of Populus and Salix continuously irrigated with landfill leachate II. soils and early tree development.

PubMed

Zalesny, Ronald S; Bauer, Edmund O

2007-01-01

Soil contaminant levels and early tree growth data are helpful for assessing phytoremediation systems. Populus (DN17, DN182, DN34, NM2, and NM6) and Salix (94003, 94012, S287, S566, and SX61) genotypes were irrigated with landfill leachate or municipal water and tested for differences in (1) element concentrations (P, K, Ca, Mg, S, Zn, B, Mn, Fe, Cu, Al, and Na) of a topsoil layer and a layer of sand in tanks with a cover crop of trees or no trees and (2) height, diameter, volume, and dry mass of leaves, stems, and roots. Trees were irrigated with leachate or water during the final 12 wk of the 18-wk study. Differences in most soil element concentrations were negligible (P > 0.05) for irrigation treatments and cover main effects. Phosphorous, K, Mg, S, Zn, Mn, Fe, and Al concentrations were greater in topsoil than sand (P = 0.0011 for Mg; P < 0.0001 for others). There was broad variation between genera and among clones for all growth traits. The treatment x clone interaction governed height, volume, and root dry mass, with (94012, SX61), (NM2, S566, SX61), and (S287, S566) exhibiting the greatest levels, respectively,following leachate application. Given the broad amount of variability among and within these genera, there is great potential for the identification and selection of specific genotypes with a combination of elevated phytoremediation capabilities and tree yield. From a practical standpoint, these results may be used as a baseline for the development of future remediation systems.

Dissipation and leaching of acephate, chlorpyrifos, and their main metabolites in field soils of Malaysia.

PubMed

Chai, L K; Mohd-Tahir, N; Hansen, S; Hansen, H C B

2009-01-01

Preventive treatment with insecticides at high dosing rates before planting of a new crop- soil drenching- is a common practice in some tropical intensive cropping systems, which may increase the risk of leaching, soil functioning, and pesticide uptake in the next crop. The degradation rates and migration of acephate and chlorpyrifos and their primary metabolites, methamidophos and 3,5,6-trichloropyridinol (TCP), have been studied in clayey red yellow podzolic (Typic Paleudults), alluvial (Typic Udorthents), and red yellow podzolic soils (Typic Kandiudults) of Malaysia under field conditions. The initial concentrations of acephate and chlorpyrifos in topsoils were found to strongly depend on solar radiation. Both pesticides and their metabolites were detected in subsoils at the deepest sampling depth monitored (50 cm) and with maximum concentrations up to 2.3 mg kg(-1) at soil depths of 10 to 20 cm. Extraordinary high dissipation rates for weakly sorbed acephate was in part attributed to preferential flow which was activated due to the high moisture content of the soils, high precipitation and the presence of conducting macropores running from below the A horizons to at least 1 m, as seen from a dye tracer experiment. Transport of chlorpyrifos and TCP which both sorb strongly to soil organic matter was attributed to macropore transport with soil particles. The half-lives for acephate in topsoils were 0.4 to 2.6 d while substantially longer half-lives of between 12.6 and 19.8 d were observed for chlorpyrifos. The transport through preferential flow of strongly sorbed pesticides is of concern in the tropics.

Degradation kinetics of ptaquiloside in soil and soil solution.

PubMed

Ovesen, Rikke Gleerup; Rasmussen, Lars Holm; Hansen, Hans Christian Bruun

2008-02-01

Ptaquiloside (PTA) is a carcinogenic norsesquiterpene glycoside produced in bracken (Pteridium aquilinum (L.) Kuhn), a widespread, aggressive weed. Transfer of PTA to soil and soil solution eventually may contaminate groundwater and surface water. Degradation rates of PTA were quantified in soil and soil solutions in sandy and clayey soils subjected to high natural PTA loads from bracken stands. Degradation kinetics in moist soil could be fitted with the sum of a fast and a slow first-order reaction; the fast reaction contributed 20 to 50% of the total degradation of PTA. The fast reaction was similar in all horizons, with the rate constant k(1F) ranging between 0.23 and 1.5/h. The slow degradation, with the rate constant k(1S) ranging between 0.00067 and 0.029/ h, was more than twice as fast in topsoils compared to subsoils, which is attributable to higher microbial activity in topsoils. Experiments with sterile controls confirmed that nonmicrobial degradation processes constituted more than 90% of the fast degradation and 50% of the slow degradation. The lower nonmicrobial degradation rate observed in the clayey compared with the sandy soil is attributed to a stabilizing effect of PTA by clay silicates. Ptaquiloside appeared to be stable in all soil solutions, in which no degradation was observed within a period of 28 d, in strong contrast to previous studies of hydrolysis rates in artificial aqueous electrolytes. The present study predicts that the risk of PTA leaching is controlled mainly by the residence time of pore water in soil, soil microbial activity, and content of organic matter and clay silicates.

Soil Carbon and Nutrient Changes Associated with Deforestation for Pasture in Southern Costa Rica

NASA Technical Reports Server (NTRS)

Huth, Timothy J.; Porder, Stephen; Chaves, Joaquin; Whiteside, Jessica H.

2012-01-01

We assessed the effects of deforestation on soil carbon (C) and nutrient stocks in the premontane landscape near Las Cruces Biological Station in southern Costa Rica, where forests were cleared for pasture in the mid-1960s. We excavated six soil pits to a depth of 1 m in both pasture and primary forest, and found that C stocks were 20 kg C per square meters in both settings. Nevertheless, soil delta C-13 suggests 50 percent of the forest-derived soil C above 40 cm depth has turned over since deforestation. Soil nitrogen (N) and phosphorus (P) stocks derived from the soil pits were not significantly different between land uses (P = 0.43 and 0.61, respectively). At a larger spatial scale, however, the ubiquity of ruts produced by cattle-induced erosion indicates that there are substantial soil effects of grazing in this steep landscape. Ruts averaged 13 cm deep and covered 45 percent of the landscape, and thus are evidence of the removal of 0.7 Mg C/ ha/yr, and 70, 9 and 40 kg/ha/yr of N, P and potassium (K), respectively. Subsoils in this region are 10 times less C- and N-rich, and 2 times less P- and K-rich than the topsoil. Thus, rapid topsoil loss may lead to a decline in pasture productivity in the coming decades. These data also suggest that the soil C footprint of deforestation in this landscape may be determined by the fate of soil C as it is transported downstream, rather than C turnover in situ.

Minesoil grading and ripping affect black walnut growth and survival

DOE Office of Scientific and Technical Information (OSTI.GOV)

Josiah, S.J.

In 1980 and 1981, the Botany Department of Southern Illinois University and Sahara Coal Company, Inc. of Harrisburg, Illinois established a series of experimental tree plantings, including black walnut, on a variety of minesoils to explore the effects of different intensities of grading on tree growth. Subsequent walnut stem and root growth were examined during 1985 on five different mine sites: unmined former agricultural land, graded minespoil, replaced (with pan scrapers) topsoil over graded spoil, ripped-graded spoil, and ungraded spoil. Soil bulk density, resistance to penetration, and spoil/soil fertility levels were also measured. The most vigorous trees were found onmore » sites having the lowest soil bulk density and soil strength and lacking horizontal barriers to root growth - the ungraded and ripped sites. Topsoiled sites had the poorest growth and survival, and the greatest stem dieback of any site measured, probably attributable to the confinement of root growth to the upper 15 cm of friable soil above the severely compacted zone. The overall results indicate that most of the minesoil construction techniques examined in this study, which are representative of techniques commonly used in the midwestern US, cause severe minesoil compaction and do not create the proper soil conditions necessary for the survival and vigorous growth of black walnut. Ripping compacted spoil in this and other studies proved to be very effective in alleviating the negative impacts of minesoil compaction. When planning surface mine reclamation activities, ripping should be considered as a possible ameliorative technique when compaction of mined lands is unavoidable and trees are the desired vegetative cover. 4 figures.« less

No shift to a deeper water uptake depth in response to summer drought of two lowland and sub-alpine C₃-grasslands in Switzerland.

PubMed

Prechsl, Ulrich E; Burri, Susanne; Gilgen, Anna K; Kahmen, Ansgar; Buchmann, Nina

2015-01-01

Temperate C3-grasslands are of high agricultural and ecological importance in Central Europe. Plant growth and consequently grassland yields depend strongly on water supply during the growing season, which is projected to change in the future. We therefore investigated the effect of summer drought on the water uptake of an intensively managed lowland and an extensively managed sub-alpine grassland in Switzerland. Summer drought was simulated by using transparent shelters. Standing above- and belowground biomass was sampled during three growing seasons. Soil and plant xylem waters were analyzed for oxygen (and hydrogen) stable isotope ratios, and the depths of plant water uptake were estimated by two different approaches: (1) linear interpolation method and (2) Bayesian calibrated mixing model. Relative to the control, aboveground biomass was reduced under drought conditions. In contrast to our expectations, lowland grassland plants subjected to summer drought were more likely (43-68%) to rely on water in the topsoil (0-10 cm), whereas control plants relied less on the topsoil (4-37%) and shifted to deeper soil layers (20-35 cm) during the drought period (29-48%). Sub-alpine grassland plants did not differ significantly in uptake depth between drought and control plots during the drought period. Both approaches yielded similar results and showed that the drought treatment in the two grasslands did not induce a shift to deeper uptake depths, but rather continued or shifted water uptake to even more shallower soil depths. These findings illustrate the importance of shallow soil depths for plant performance under drought conditions.

New strategies to increase the restoration success of post-mining landscapes: the application of cyanobacteria to seed-based rehabilitation programs

NASA Astrophysics Data System (ADS)

Muñoz-Rojas, Miriam; Raúl Román Fernández, José; Roncero Ramos, Beatriz; Cantón Castilla, Yolanda

2017-04-01

Despite the large efforts and investments to dryland ecosystems restoration worldwide, land rehabilitation in these areas has very low rates of success. Most of the challenges in landscape-scale restoration come from the lack of suitable soil substrates to support plant establishment and to ultimately achieve functional ecosystems. A common practice during extractive operations such as open-cut and strip mining is the removal of the topsoil layer that is subsequently stockpiled and respread in areas targeted for restoration. This topsoil is a crucial source of seeds, nutrients, and microorganisms but is a scarce resource which challenges the success of many restoration programs. In these conditions, the use of direct seeding of key native plant species becomes critical to reinstate biodiverse vegetation communities. Alternative soil substrates such as overburden or waste materials produced in mining operations are increasingly being used as growth media in restoration. However, these soil substrates can have inadequate levels of pH or salinity for plant growth and in most cases are depleted in organic materials and nutrients. In these conditions, the establishment of native plant species can be extremely difficult with a consequent potential loss of biodiversity. Development of appropriate soil structures such as technosols can be extremely expensive and demanding in terms of time and natural resources soils and therefore new approached need to be explored. In the last years, the potential of cyanobacteria biological crust to restore soil functionality in degraded has been highlighted because of their important role in controlling soil structure, preventing soil erosion and N and C fixation. Nevertheless, many research gaps still remain in their application to restore soil functionality in seed-based restoration practices. In this study, we test the potential of cyanobacteria inoculation to restore soil functions of soil materials used in post-mine restoration. Soil substrates consisted of topsoil retrieved from previously stockpiled material, an overburden waste material commonly used in landform reconstruction due to its erosive stability and physical competency, and a mixture of both substrates. These materials were collected from an active mine site in the mining intensive Pilbara region and inoculated with a mixture of soil cyanobacteria from three nitrogen-fixing genera (Nostoc, Scytonema and Tolypothrix). Further analyses need to be undertaken but preliminary results showed that after only 4 weeks, cyanobacteria rapidly colonized the mine substrates as cyanobacteria surface cover significantly increased during the time of study.The output of this research is the first step to effectively address the reconstruction of soil substrates that can provide support to the establishment of biodiverse vegetation communities in landscape-scale seed-based mine restoration.

Cryptogamic communities in biological soil crusts in arid deserts of China: Diversity and their relationships to habitats in different scales

NASA Astrophysics Data System (ADS)

Li, X. R.; He, M. Z.; Li, X. J.; Jia, R. L.

2012-04-01

Biological soil crusts (BSCs) are widespread communities of various diminutive organisms, including cryptogams such as cyanobacteria, algae, lichens and mosses, and other invisible organisms that are closely integrated with particles of topsoil. Few studies have considered their diversity and distribution pattern as related to environmental and climatic factors at different scales - in particular, little is known concerning the factors inducing the differences in crustal floral diversity for arid deserts in China. We investigated the distribution and characteristics of crustal communities with a total of 350 soil samplings in the main desert regions of northern China: the Horqin Sandland, Mu Us Sandland-Ordos Plateau, Tengger-Alxa Plateau, Qaidam Desert and Guerbantunggut Desert, which present a precipitation gradient, reducing from 450 mm in eastern to 80-100 mm in western deserts. The maximum cryptogamic species richness in crustal communities was 66, 42, 56, 22 and 54, respectively, in the above deserts. In general, species richness and biomass of crustal mosses were positive related with precipitation, while that of cyanobacteria and algae, as well as lichens were negative at a landscape scale. The results indicated topsoil physiochemical properties largely influenced the distribution pattern of crustal communities at the regional scale. Fine-textured and gypsum soils and soils with higher pH were favorable for various lichens, which were restricted by soils with higher total salt content. Moss species and biomass were closely related with soil water content rather than other properties, whereas there was higher diversity in cyanobacteria and algae at the site with relatively dry topsoil. In addition, the cover and biomass of mosses was positive correlated with the cover of C3 plants such as xerophytic shrubs due to providing shade. However, cover and biomass of lichens, cyanobacteria and algae were closely correlated with C4 plants, especially annuals, possibly as they created a relative stable and safe site for seed germination and survival in an aeolian environment, and increased carbon and nitrogen input into these nutrient-poor sandy substrates. At a small scale, diversity and biomass of crustal communities were largely determined by surface micro-geomorphology. Complex micro-geomorphology, such as small shrub-soil mounds and different location of stabilized dunes, has created various habitats that facilitate the maintaining of higher species diversity in BSCs due to re-allocation of dustfall deposition and surface water regime. These findings suggested that any disturbances will induce changes in cryptogamic diversity at the small scale. Variation of rainfall regime in future will result in conversion amongst the different types of BSCs, and may contribute to changes in desert ecosystem structure and function. Keywords: cryptogam species; distribution characteristics; precipitation gradient; soil physiochemical properties; different scale; Chinese deserts

Life cycle impacts of topsoil erosion on aquatic ecosystems: case study on Eucalyptus globulus forest

NASA Astrophysics Data System (ADS)

Quinteiro, Paula; Van de Broek, Marijn; Cláudia Dias, Ana; Ridoutt, Bradley; Arroja, Luís

2016-04-01

High concentrations of suspended solids (SS), particularly in the clay and silt size fractions, reaching lotic environments and remaining in suspension can be a significant stressors to the biodiversity of these aquatic systems, degrading the water quality and directly affecting the aquatic biota, namely macroinvertebrates, algae and macrophytes. This damage is presently not considered in Life Cycle Assessment studies. This study is devoted to the effects of SS into freshwater systems due to topsoil erosion by water (environmental mechanism), translated into damage to aquatic ecosystem diversity (endpoint impact category), namely to macroinvertebrates, algae and macrophytes. For this, we have developed a framework to conduct an erosion inventory using the WaTEM/SEDEM model and linked this with, a method to derive regional characterisation for endpoint damage on aquatic ecosystem diversity. A case study was performed for Eucalyptus globulus stands in Portugal, with a functional unit of one hectare of land under production forestry management. To demonstrate how this newly SS ecosystem method can help to improve the environmental assessment in forestry, results were compared with the earlier commonly used impact categories from ReCiPe method. The relevance of the impact from SS delivery to freshwater streams is shown, providing a more comprehensive assessment of the SS impact from land use systems on aquatic environments. The SS impacts ranged from 15.5 to 1234.9 PDF.m3.yr.ha-1.revolution-1 for macroinvertebrates, and from 5.2 to 411.9 PDF.m3.yr.ha-1.revolution-1 for algae and macrophytes. For some stands, SS potential impacts on macroinvertebrates have the same order of magnitude than freshwater eutrophication, freshwater ecotoxicity, terrestrial ecotoxicity and terrestrial acidification impacts. For algae and macrophytes, most of the stands present SS impacts of the same order of magnitude as terrestrial ecotoxicity, one order of magnitude higher than freshwater eutrophication, and two orders of magnitude lower than freshwater ecotoxicity and terrestrial acidification. The SS impact results allow to conclude that the increase of SS in the water column can cause biodiversity damage and that the calculated impacts can have a similar or even higher contribution to the total environmental impact than the commonly established endpoint impact categories of the ReCiPe method (such as freshwater eutrophication, freshwater ecotoxicity, terrestrial ecotoxicity and terrestrial acidification). The present study proves that SS impacts on aquatic organisms can vary substantially when using a detailed regionalisation level such as the local resolution scale. A wide application of the framework and method developed at a local scale enable the establishment of a regionalised SS inventory database and a deep characterisation of the potential environmental impacts of SS on local aquatic environments. Keywords: Eucalyptus globulus, land use, life cycle assessment, suspended solids, topsoil erosion

Whole Watershed Quantification of Net Carbon Fluxes by Erosion and Deposition within the Christina River Basin Critical Zone Observatory

NASA Astrophysics Data System (ADS)

Aufdenkampe, A. K.; Karwan, D. L.; Aalto, R. E.; Marquard, J.; Yoo, K.; Wenell, B.; Chen, C.

2013-12-01

We have proposed that the rate at which fresh, carbon-free minerals are delivered to and mix with fresh organic matter determines the rate of carbon preservation at a watershed scale (Aufdenkampe et al. 2011). Although many studies have examined the role of erosion in carbon balances, none consider that fresh carbon and fresh minerals interact. We believe that this mechanism may be a dominant sequestration process in watersheds with strong anthropogenic impacts. Our hypothesis - that the rate of mixing fresh carbon with fresh, carbon-free minerals is a primary control on watershed-scale carbon sequestration - is central to our Christina River Basin Critical Zone Observatory project (CRB-CZO, http://www.udel.edu/czo/). The Christina River Basin spans 1440 km2 from piedmont to Atlantic coastal plain physiographic provinces in the states of Pennsylvania and Delaware, and experienced intensive deforestation and land use beginning in the colonial period of the USA. Here we present a synthesis of multi-disciplinary data from the CRB-CZO on materials as they are transported from sapprolite to topsoils to colluvium to suspended solids to floodplains, wetlands and eventually to the Delaware Bay estuary. At the heart of our analysis is a spatially-integrated, flux-weighted comparison of the organic carbon to mineral surface area ratio (OC/SA) of erosion source materials versus transported and deposited materials. Because source end-members - such as forest topsoils, farmed topsoils, gullied subsoils and stream banks - represent a wide distribution of initial, pre-erosion OC/SA, we quantify source contributions using geochemical sediment fingerprinting approaches (Walling 2005). Analytes used for sediment fingerprinting include: total mineral elemental composition (including rare earth elements), fallout radioisotope activity for common erosion tracers (beryllium-7, beryllium-10, lead-210, cesium-137), particle size distribution and mineral specific surface area, in addition to organic carbon and nitrogen content with stable isotope (13C, 15N) and radiocarbon (14C) abundance to quantify OC/SA and organic carbon sources and mean age. We then use multivariate mixing model analysis to quantify the fractional contribution of each source end-member to each sample of suspended or deposited sediments. Last, we calculate a predicted OC/SA based on source end-member mixing and compare to the measured OC/SA to quantify net change in mineral complexed carbon. Aufdenkampe, A.K. et al. Riverine coupling of biogeochemical cycles between land, oceans, and atmosphere. Frontiers Ecol. Environ. 9, 53-60 (2011). Walling, D. E. Tracing suspended sediment sources in catchments and river systems. Sci. Total Environ. 34, 159-184 (2005).

Massive carbon addition to an organic-rich Andosol increased the subsoil but not the topsoil carbon stock

NASA Astrophysics Data System (ADS)

Zieger, Antonia; Kaiser, Klaus; Ríos Guayasamín, Pedro; Kaupenjohann, Martin

2018-05-01

Andosols are among the most carbon-rich soils, with an average of 254 Mg ha-1 organic carbon (OC) in the upper 100 cm. A current theory proposes an upper limit for OC stocks independent of increasing carbon input, because of finite binding capacities of the soil mineral phase. We tested the possible limits in OC stocks for Andosols with already large OC concentrations and stocks (212 g kg-1 in the first horizon, 301 Mg ha-1 in the upper 100 cm). The soils received large inputs of 1800 Mg OC ha-1 as sawdust within a time period of 20 years. Adjacent soils without sawdust application served as controls. We determined total OC stocks as well as the storage forms of organic matter (OM) of five horizons down to 100 cm depth. Storage forms considered were pyrogenic carbon, OM of < 1.6 g cm-3 density and with little to no interaction with the mineral phase, and strongly mineral-bonded OM forming particles of densities between 1.6 and 2.0 g cm-3 or > 2.0 g cm-3. The two fractions > 1.6 g cm-3 were also analysed for aluminium-organic matter complexes (Al-OM complexes) and imogolite-type phases using ammonium-oxalate-oxalic-acid extraction and X-ray diffraction (XRD). Pyrogenic organic carbon represented only up to 5 wt % of OC, and thus contributed little to soil OM. In the two topsoil horizons, the fraction between 1.6 and 2.0 g cm-3 had 65-86 wt % of bulk soil OC and was dominated by Al-OM complexes. In deeper horizons, the fraction > 2.0 g cm-3 contained 80-97 wt % of the bulk soil's total OC and was characterized by a mixture of Al-OM complexes and imogolite-type phases, with proportions of imogolite-type phases increasing with depth. In response to the sawdust application, only the OC stock at 25-50 cm depth increased significantly (α = 0.05, 1 - β = 0.8). The increase was entirely due to increased OC in the two fractions > 1.6 g cm-3. However, there was no significant increase in the total OC stocks within the upper 100 cm. The results suggest that long-term large OC inputs cannot be taken up by the obviously OC-saturated topsoil but induce downward migration and gradually increasing storage of OC in subsurface soil layers. The small additional OC accumulation despite the extremely large OC input over 20 years, however, shows that long time periods of high input are needed to promote the downward movement and deep soil storage of OC.

Spatial variation in herbicide leaching from a marine clay soil via subsurface drains

PubMed Central

Ulén, Barbro M; Larsbo, Mats; Kreuger, Jenny K; Svanbäck, Annika

2013-01-01

Background Subsurface transport via tile drains can significantly contribute to pesticide contamination of surface waters. The spatial variation in subsurface leaching of normally applied herbicides was examined together with phosphorus losses in 24 experimental plots with water sampled flow-proportionally. The study site was a flat, tile-drained area with 60% marine clay in the topsoil in southeast Sweden. The objectives were to quantify the leaching of frequently used herbicides from a tile drained cracking clay soil and to evaluate the variation in leaching within the experimental area and relate this to topsoil management practices (tillage method and structure liming). Results In summer 2009, 0.14, 0.22 and 1.62%, respectively, of simultaneously applied amounts of MCPA, fluroxypyr and clopyralid were leached by heavy rain five days after spraying. In summer 2011, on average 0.70% of applied bentazone was leached by short bursts of intensive rain 12 days after application. Peak flow concentrations for 50% of the treated area for MCPA and 33% for bentazone exceeded the Swedish no-effect guideline values for aquatic ecosystems. Approximately 0.08% of the glyphosate applied was leached in dissolved form in the winters of 2008/2009 and 2010/2011. Based on measurements of glyphosate in particulate form, total glyphosate losses were twice as high (0.16%) in the second winter. The spatial inter-plot variation was large (72–115%) for all five herbicides studied, despite small variations (25%) in water discharge. Conclusions The study shows the importance of local scale soil transport properties for herbicide leaching in cracking clay soils. © 2013 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. PMID:23658148

Impact of an iron mine and a nickel smelter at the Norwegian/Russian border close to the Barents Sea on surface soil magnetic susceptibility and content of potentially toxic elements.

PubMed

Magiera, Tadeusz; Zawadzki, Jarosław; Szuszkiewicz, Marcin; Fabijańczyk, Piotr; Steinnes, Eiliv; Fabian, Karl; Miszczak, Ewa

2018-03-01

An important problem in soil magnetometry is unraveling the soil contamination signal in areas with multiple emitters. Here, geophysical and geochemical measurements were performed at four sites on a north - south transect along the Pasvik River in the Barents Region (northern Norway). These sites are influenced by depositions from the Bjørnevatn iron mine and a Ni-Cu smelter in Nikel, Russia. To relate the degree and type of pollution from these sources to the corresponding magnetic signal, the topsoil concentrations of 12 Potentially Toxic Elements (PTEs) (As, Cd, Co, Cr, Cu, Fe, Mo, Ni, Pb, Se, Ti, Zn), were determined, magnetic hysteresis parameters and thermomagnetic properties were measured. In situ magnetic low-field susceptibility decreases from north to south with increasing distance from the iron mine. Relatively large magnetic multidomain grains of magnetite and/or titanomagnetite are responsible for the strong magnetic signal from the topsoil close to Bjørnevatn. These particles are related to increased enrichment factors of As, Mo and Cu, yielding high positive correlation coefficients with susceptibility values. At a site furthest away from the iron mine and located 7 km from the Ni-Cu smelter magnetic susceptibility values are much lower but significant positive correlations on the level of p < .1 with 8 PTEs (Ni, Cu, Co, Se, As, Zn, Cd, Cr) have been observed. The magnetic signal in this area is due to fine-grained primary sulphides and secondary fine-grained magnetite and/or maghemite. Copyright © 2017 Elsevier Ltd. All rights reserved.

Combination of geo- pedo- and technogenic magnetic and geochemical signals in soil profiles - Diversification and its interpretation: A new approach.

PubMed

Szuszkiewicz, Marcin; Łukasik, Adam; Magiera, Tadeusz; Mendakiewicz, Maria

2016-07-01

Magnetic and geochemical parameters of soils are determined with respect to geology, pedogenesis and anthropopression. Depending on local conditions these factors affect magnetic and geochemical signals simultaneously or in various configurations. We examined four type of soils (Entic Podzol, Eutric Cambisol, Humic Cambisol and Dystric Cambisol) developed on various bedrock (the Tumlin Sandstone, basaltoid, amphibolite and serpentinite, respectively). Our primary aim was to characterize the origin and diversification of the magnetic and geochemical signal in soils in order to distinguish the most reliable methods for correct interpretation of measured parameters. Presented data include selected parameters, both magnetic (mass magnetic susceptibility - χ, frequency-dependent magnetic susceptibility - χfd and thermomagnetic susceptibility measurement - TSM), and geochemical (selected heavy metal contents: Co, Cr, Cu, Fe, Mn, Ni, Pb, Zn). Additionally, the enrichment factor (EF) and index of geoaccumulation (Igeo) were calculated. Our results suggest the following: (1) the χ/Fe ratio may be a reliable indicator for determining changes of magnetic signal origin in soil profiles; (2) magnetic and geochemical signals are simultaneously higher (the increment of χ and lead and zinc was noted) in topsoil horizons because of the deposition of technogenic magnetic particles (TMPs); (3) EF and Igeo evaluated for lead and zinc unambiguously showed anthropogenic influence in terms of increasing heavy metal contents in topsoil regardless of bedrock or soil type; (4) magnetic susceptibility measurements supported by TSM curves for soil samples of different genetic horizons are a helpful tool for interpreting the origin and nature of the mineral phases responsible for the changes of magnetic susceptibility values. Copyright © 2016 Elsevier Ltd. All rights reserved.

Rooting-depth of Atriplex canescens (fourwing saltbush) in mine spoils at the Navajo Mine, northwestern New Mexico

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stutz, H.C.; Buchanan, B.A.

1990-12-31

The distribution of roots was determined for fourteen mature plants of Atriplex canescens (fourwing saltbush) growing on mine spoils at the Navajo Mine in northwestern New Mexico and for two plants growing in contiguous unmined native soil. In all instances the amount of roots, by length, was negatively correlated with depth and positively correlated with percent water-content of the soils. The majority of roots (59%) were in the upper 100 cm; 72% were in the upper 150 cm; and 84% were in the upper 200 cm. These percentages were higher for plants growing on backslopes (64%, 77% and 88%, respectively)more » and much higher for those growing in native soils (84%, 93% and 96%, respectively). Most of the roots (83%) were less than 0.1 mm in diameter, and 93% were less than 0.5 mm in diameter. Plants growing in topsoiled sites had more roots per unit volume of soil (1.3 cm per cc of soil) than those growing in non-topsoiled sites (1.1 cm per cc of soil). Those growing in backslopes had more roots (1.3 cm per cc of soil) than growing in swales (1.0 cm per cc of soil) and those growing in soils that contained no fly-ash had more (0.78 cm per cc) than those growing in soils that contain fly ash (0.12 cm per cc of soil). Plants growing in native soils had a greater proportion of their roots near the surface than plants growing in mined soils. Plants growing in swales had a greater proportion of their roots below two meters than plants growing on backslopes.« less

Long-term Effects of Organic Waste Fertilizers on Soil Structure, Tracer Transport, and Leaching of Colloids.

PubMed

Lekfeldt, Jonas Duus Stevens; Kjaergaard, Charlotte; Magid, Jakob

2017-07-01

Organic waste fertilizers have previously been observed to significantly affect soil organic carbon (SOC) content and soil structure. However, the effect of organic waste fertilizers on colloid dispersibility and leaching of colloids from topsoil has not yet been studied extensively. We investigated how the repeated application of different types of agricultural (liquid cattle slurry and solid cattle manure) and urban waste fertilizers (sewage sludge and composted organic household waste) affected soil physical properties, colloid dispersion from aggregates, tracer transport, and colloid leaching from intact soil cores. Total porosity was positively correlated with SOC content. Yearly applications of sewage sludge increased absolute microporosity (pores <30 μm) and decreased relative macroporosity (pores >30 μm) compared with the unfertilized control, whereas organic household waste compost fertilization increased both total porosity and the absolute porosity in all pore size classes (though not significant for 100-600 μm). Treatments receiving large amounts of organic fertilizers exhibited significantly lower levels of dispersible colloids compared with an unfertilized control and a treatment that had received moderate applications of cattle slurry. The content of water-dispersible colloids could not be explained by a single factor, but differences in SOC content, electrical conductivity, and sodium adsorption ratio were important factors. Moreover, we found that the fertilizer treatments did not significantly affect the solute transport properties of the topsoil. Finally, we found that the leaching of soil colloids was significantly decreased in treatments that had received large amounts of organic waste fertilizers, and we ascribe this primarily to treatment-induced differences in effluent electrical conductivity during leaching. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Spatial distribution of Cd and Cu in soils in Shenyang Zhangshi Irrigation Area (SZIA), China*

PubMed Central

Sun, Li-na; Yang, Xiao-bo; Wang, Wen-qing; Ma, Li; Chen, Su

2008-01-01

Heavy metal contamination of soils, derived from sewage irrigation, mining and inappropriate utilization of various agrochemicals and pesticides, and so on, has been of wide concern in the last several decades. The Shenyang Zhangshi Irrigation Area (SZIA) in China is a representative area of heavy metal contamination of soils resulting from sewage irrigation for about 30 years. This study investigated the spatial distribution and temporal variation of soil cadmium (Cd) and copper (Cu) contamination in the SZIA. The soil samples were collected from the SZIA in 1990 and 2004; Cd and Cu in soils was analyzed and then the spatial distribution and temporal variation of Cd and Cu in soils were modeled using Kriging methods. The results show that long-term sewage irrigation had caused serious Cd and Cu contamination in soils. The mean and the maximum of soil Cd are markedly higher than the levels in second grade standard soil (LSGSS) in China, and the maximum of soil Cu is close to the LSGSS in China in 2004 and is more than the LSGSS in China in 1990. The contamination magnitude of soil Cd and the soil extent of Cd contamination had evidently increased since sewage irrigation ceased in 1992. The contamination magnitude of soil Cu and the soil extent of Cu contamination had evidently increased in topsoil, but obviously decresed in subsoil. The soil contamination of Cd and Cu was mainly related to Cd and Cu reactivation of contaminated sediments in Shenyang Xi River and the import of Cd and Cu during irrigation. The eluviation of Cd and Cu in contaminated topsoil with rainfall and irrigation water was another factor of temporal-spatial variability of Cd and Cu contamination in soils. PMID:18357631

Atmospheric deposition of mercury and cadmium impacts on topsoil in a typical coal mine city, Lianyuan, China.

PubMed

Liang, Jie; Feng, Chunting; Zeng, Guangming; Zhong, Minzhou; Gao, Xiang; Li, Xiaodong; He, Xinyue; Li, Xin; Fang, Yilong; Mo, Dan

2017-12-01

Mercury (Hg) and cadmium (Cd) in the atmosphere from coal combustion emissions play an important role in soil pollution. Therefore, the purposes of this study were to quantitatively evaluate the atmospheric Hg and Cd deposition and to determine the influence of atmospheric deposition on Hg and Cd contents in surface soil in a typical coal mine city. Atmospheric deposition samples were collected from May 2015 to May 2016 at 17 sites located in industrial, agricultural and forest areas in the Lianyuan city. Atmospheric Hg and Cd deposition fluxes in the different land use types showed high variability. Curvilinear regression analysis suggested that the atmospheric Hg deposition fluxes were positively related with Hg contents in soils (R 2  = 0.86359, P < 0.001). In addition, atmospheric Cd deposition fluxes were also positively correlated with Cd contents in soils when the site LY02, LY04 and LY05 (all belong to agricultural land) were not included in the fitting (R 2  = 0.82458, P < 0.001). When they were included, there was no significant relationship between them (R 2  = 0.2039, P = 0.05). The accumulation of Hg and Cd concentration in topsoil due to the influence of atmospheric deposition will increase rapidly in the next 30 years, and the mean value of the increment will reach 2.6007 and 33.344 mg kg -1 . After 30 years, the Hg and Cd concentration will increase slowly. The present study advocates that much attention should be paid to the potential ecological hazards in soil resulting from the atmospheric Hg and Cd deposition. Copyright © 2017 Elsevier Ltd. All rights reserved.

Soil Quality of Bauxite Mining Areas

NASA Astrophysics Data System (ADS)

Terezinha Gonçalves Bizuti, Denise; Dinarowski, Marcela; Casagrande, José Carlos; Silva, Luiz Gabriel; Soares, Marcio Roberto; Henrique Santin Brancalion, Pedro

2015-04-01

The study on soil quality index (SQI) aims to assess the current state of the soil after use and estimating its recovery through sustainable management practices This type of study is being used in this work in order to check the efficiency of forest recovery techniques in areas that have been deeply degraded by bauxite mining process, and compare them with the area of native forest, through the determination of SQI. Treatments were newly mined areas, areas undergoing restoration (topsoil use with planting of native forest species), areas in rehabilitation (employment of the green carpet with topsoil and planting of native forest species) and areas of native forests, with six repetitions, in areas of ALCOA, in the municipality of Poços de Caldas/MG. To this end, we used the additive pondered model, establishing three functions: Fertility, water movement and root development, based on chemical parameters (organic matter, base saturation, aluminum saturation and calcium content); physical (macroporosity, soil density and clay content); and microbiological testing (basal respiration by the emission of CO2 ). The SQIs obtained for each treatment was 41%, 56%, 63% and 71% for newly mined areas, native forest, areas in restoration and rehabilitation, respectively. The recovering technique that most approximates the degraded soil to the soil of reference is the restoration, where there was no statistically significant difference of areas restored with native forest. It was found that for the comparison of the studied areas must take into account the nutrient cycling, that disappear with plant removal in mining areas, once the soil of native forest features low fertility and high saturation by aluminum, also taking in account recovering time.

Negative Emissions Technology

NASA Astrophysics Data System (ADS)

Day, Danny

2006-04-01

Although `negative emissions' of carbon dioxide need not, in principle, involve use of biological processes to draw carbon out of the atmosphere, such `agricultural' sequestration' is the only known way to remove carbon from the atmosphere on time scales comparable to the time scale for anthropogenic increases in carbon emissions. In order to maintain the `negative emissions' the biomass must be used in such a way that the resulting carbon dioxide is separated and permanently sequestered. Two options for sequestration are in the topsoil and via geologic carbon sequestration. The former has multiple benefits, but the latter also is needed. Thus, although geologic carbon sequestration is viewed skeptically by some environmentalists as simply a way to keep using fossil fuels---it may be a key part of reversing accelerating climate forcing if rapid climate change is beginning to occur. I will first review the general approach of agricultural sequestration combined with use of resulting biofuels in a way that permits carbon separation and then geologic sequestration as a negative emissions technology. Then I discuss the process that is the focus of my company---the EPRIDA cycle. If deployed at a sufficiently large scale, it could reverse the increase in CO2 concentrations. I also estimate of benefits --carbon and other---of large scale deployment of negative emissions technologies. For example, using the EPRIDA cycle by planting and soil sequestering carbon in an area abut In 3X the size of Texas would remove the amount of carbon that is being accumulated worldwide each year. In addition to the atmospheric carbon removal, the EPRIDA approach also counters the depletion of carbon in the soil---increasing topsoil and its fertility; reduces the excess nitrogen in the water by eliminating the need for ammonium nitrate fertilizer and reduces fossil fuel reliance by providing biofuel and avoiding natural gas based fertilizer production.

Enrichment of Desulfitobacterium spp. from forest and grassland soil using the O-demethylation of phenyl methyl ethers as a growth-selective process.

PubMed

Mingo, Felix Sebastian; Diekert, Gabriele; Studenik, Sandra

2016-02-01

The O-demethylation of phenyl methyl ethers under anaerobic conditions is a metabolic feature of acetogens and Desulfitobacterium spp. Desulfitobacteria as well as most acetogens are Gram-positive bacteria with a low GC content and belong to the phylum Firmicutes. The consumption of the phenyl methyl ether syringate was studied in enrichment cultures originating from five different topsoils. Desulfitobacterium spp. were detected in all topsoils via quantitative PCR. Desulfitobacteria could be enriched using the O-demethylation of syringate as a growth-selective process. The enrichment was significantly favoured by an external electron acceptor such as 3-chloro-4-hydroxyphenylacetate or thiosulfate. Upon cultivation in the presence of syringate and thiosulfate, which naturally occur in soil, a maximum number of 16S rRNA gene copies of Desulfitobacterium spp. was reached within the first three subcultivation steps and accounted for 3-10% of the total microbial community depending on the soil type. Afterwards, a loss of Desulfitobacterium gene copies was observed. Community analyses revealed that Proteobacteria, Acidobacteria, Actinobacteria and Bacteroidetes were the main phyla in the initial soil samples. Upon addition of syringate and thiosulfate as growth substrates, these phyla were rapidly outcompeted by Firmicutes, which were under-represented in soil. The main Firmicutes genera identified were Alkalibaculum, Clostridium, Sporobacterium, Sporomusa and Tissierella, which might be responsible for outcompeting the desulfitobacteria. Most of these organisms belong to the acetogens, which have previously been described to demethylate phenyl methyl ethers. The shift of the native community structure to almost exclusively Firmicutes supports the participation of members of this phylum in environmental demethylation processes.

Matrix association effects on hydrodynamic sorting and degradation of terrestrial organic matter during cross-shelf transport in the Laptev and East Siberian shelf seas

NASA Astrophysics Data System (ADS)

Tesi, Tommaso; Semiletov, Igor; Dudarev, Oleg; Andersson, August; Gustafsson, Örjan

2016-03-01

This study seeks an improved understanding of how matrix association affects the redistribution and degradation of terrigenous organic carbon (TerrOC) during cross-shelf transport in the Siberian margin. Sediments were collected at increasing distance from two river outlets (Lena and Kolyma Rivers) and one coastal region affected by erosion. Samples were fractionated according to density, size, and settling velocity. The chemical composition in each fraction was characterized using elemental analyses and terrigenous biomarkers. In addition, a dual-carbon-isotope mixing model (δ13C and Δ14C) was used to quantify the relative TerrOC contributions from active layer (Topsoil) and Pleistocene Ice Complex Deposits (ICD). Results indicate that physical properties of particles exert first-order control on the redistribution of different TerrOC pools. Because of its coarse nature, plant debris is hydraulically retained in the coastal region. With increasing distance from the coast, the OC is mainly associated with fine/ultrafine mineral particles. Furthermore, biomarkers indicate that the selective transport of fine-grained sediment results in mobilizing high-molecular weight (HMW) lipid-rich, diagenetically altered TerrOC while lignin-rich, less degraded TerrOC is retained near the coast. The loading (µg/m2) of lignin and HMW wax lipids on the fine/ultrafine fraction drastically decreases with increasing distance from the coast (98% and 90%, respectively), which indicates extensive degradation during cross-shelf transport. Topsoil-C degrades more readily (90 ± 3.5%) compared to the ICD-C (60 ± 11%) during transport. Altogether, our results indicate that TerrOC is highly reactive and its accelerated remobilization from thawing permafrost followed by cross-shelf transport will likely represent a positive feedback to climate warming.

Distribution of heavy metals in agricultural soils near a petrochemical complex in Guangzhou, China.

PubMed

Li, Junhui; Lu, Ying; Yin, Wei; Gan, Haihua; Zhang, Chao; Deng, Xianglian; Lian, Jin

2009-06-01

The aim of the study was to investigate influence of an industrialized environment on the accumulation of heavy metals in agricultural soils. Seventy soil samples collected from surface layers (0-20 cm) and horizons of five selected pedons in the vicinity area of petrochemical complex in Guangzhou, China were analyzed for Zn, Cu, Pb, Cd, Hg and As concentrations, the horizontal and vertical variation of these metals were studied and geographic information system (GIS)-based mapping techniques were applied to generate spatial distribution maps. The mean concentrations of these heavy metals in the topsoils did not exceed the maximum allowable concentrations in agricultural soil of China with the exception of Hg. Significant differences between land-use types showed that Cu, Pb, Cd, Hg and As concentrations in topsoils were strongly influenced by agricultural practices and soil management. Within a radius of 1,300 m there were no marked decreasing trends for these element concentrations (except for Zn) with the increase of distance from the complex boundary, which reflected little influence of petroleum air emission on soil heavy metal accumulation. Concentrations of Zn, Cu, Pb, Cd, Hg and As in the five pedons, particularly in cultivated vegetable field and orchard, decreased with soil depth, indicating these elements mainly originated from anthropogenic sources. GIS mapping was a useful tool for evaluating spatial variability of heavy metals in the affected soil. The spatial distribution maps allowed the identification of hot-spot areas with high metal concentration. Effective measures should be taken to avoid or minimize heavy metal further contamination of soils and to remediate the contaminated areas in order to prevent pollutants affecting human health through agricultural products.

[Assessment of heavy metal pollution and potential ecological risks of urban soils in Kaifeng City, China].

PubMed

Li, Yi-Meng; Ma, Jian-Hua; Liu, De-Xin; Sun, Yan-Li; Chen, Yan-Fang

2015-03-01

Ninety-nine topsoil (0-15 cm) samples were collected from Kaifeng City, China using the grid method, and then the concentrations of As, Cd, Cr, Cu, Ni, Pb and Zn in the samples were measured by standard methods. Soil pollution levels and potential ecological risks of the heavy metals were assessed using the pollution load index (PLI) and potential ecological risk index (RI), respectively. Ordinary Kriging interpolation technique was employed to investigate the spatial distribution of PLI and RI of the city. The results showed that high pollution of Cd occurred in Kaifeng urban soils, and there was moderate pollution of Zn, slight pollution of Pb and Cu, and no pollution of Ni, Cr and As. Very high ecological risk was posed by Cd and low risk by other metals. The mean PLI of the 7 metals from all sample points was 2.53, which was categorized as moderate pollution. The average RI was 344.58 which represented a considerable ecological risk. PLI and RI shared a similar spatial distribution with high values centralized in the old industrial area in the southeast and railway stations for passengers and goods in the south of the city, followed by the old town within the ancient city wall, and low values located in the north and west areas. Cadmium was the main factor for both soil pollution and potential ecological risk primarily due to farmland topsoil in the eastern suburb of Kaifeng City with high Cd concentrations resulted from sewage irrigation deposited in the urban area by wind, human activities such as soot discharged from the chemical fertilizer plant of Kaifeng, transportation and coal combustion.

Nickel speciation in several serpentine (ultramafic) topsoils via bulk synchrotron-based techniques

DOE Office of Scientific and Technical Information (OSTI.GOV)

Siebecker, Matthew G.; Chaney, Rufus L.; Sparks, Donald L.

2017-07-01

Serpentine soils have elevated concentrations of trace metals including nickel, cobalt, and chromium compared to non-serpentine soils. Identifying the nickel bearing minerals allows for prediction of potential mobility of nickel. Synchrotron-based techniques can identify the solid-phase chemical forms of nickel with minimal sample treatment. Element concentrations are known to vary among soil particle sizes in serpentine soils. Sonication is a useful method to physically disperse sand, silt and clay particles in soils. Synchrotron-based techniques and sonication were employed to identify nickel species in discrete particle size fractions in several serpentine (ultramafic) topsoils to better understand solid-phase nickel geochemistry. Nickel commonlymore » resided in primary serpentine parent material such as layered-phyllosilicate and chain-inosilicate minerals and was associated with iron oxides. In the clay fractions, nickel was associated with iron oxides and primary serpentine minerals, such as lizardite. Linear combination fitting (LCF) was used to characterize nickel species. Total metal concentration did not correlate with nickel speciation and is not an indicator of the major nickel species in the soil. Differences in soil texture were related to different nickel speciation for several particle size fractionated samples. A discussion on LCF illustrates the importance of choosing standards based not only on statistical methods such as Target Transformation but also on sample mineralogy and particle size. Results from the F-test (Hamilton test), which is an underutilized tool in the literature for LCF in soils, highlight its usefulness to determine the appropriate number of standards to for LCF. EXAFS shell fitting illustrates that destructive interference commonly found for light and heavy elements in layered double hydroxides and in phyllosilicates also can occur in inosilicate minerals, causing similar structural features and leading to false positive results in LCF.« less

Soil nitrogen dynamics in high-altitude ski runs during the winter season (Monterosaski - Vallée d

NASA Astrophysics Data System (ADS)

Freppaz, M.; Icardi, M.; Filippa, G.; Zanini, E.

2009-04-01

In many Alpine catchments, the development of winter tourism determined a widespread change in land use, shifting from forested and cultivated lands to ski slopes. The construction of a ski slope implies a strong impact on the landscape, with potential consequences on the soil quality. In most cases, the construction procedures include the total or partial removal of the soil body, the reallocation of the fine hearth fraction, the subsequent seeding of plants and the use of organic fertilizers. This work aims to evaluate soil physical and chemical properties and nitrogen (N) dynamics in anthropogenic soils from ski slopes of different age. Study sites were located in Champoluc (AO)- NW Italy between 2400 and 2700 m ASL. Topsoils (0-10 cm depth) were sampled in 4 ski slopes hydroseeded with commercial mixtures 4, 6, 10 and 12 years earlier, and in 4 control plots at the same exposure and altitude as the ski slopes. Soil samples were characterized, N dynamics in winter was evaluated with the buried bag technique and snowpack was analyzed for chemical and physical properties. Total nitrogen (TN) content in topsoil ranged 0.75-1.06 g kg-1 and was not correlated with the ski slope age. In all but one site, the TN content was significantly lower in the ski slope than in the control plot. A positive net ammonification and nitrification throughout the winter were found in all but one ski runs. These results suggest a high variability in the evolution degree of these anthropogenic soils. The net overwinter N mineralization that we report demonstrates that these soils are biologically active during the winter season. Such activity results in a pool of labile inorganic nitrogen potentially available for plant demand at the spring snowmelt.

Effect of long-term organic fertilization on the soil pore characteristics of greenhouse vegetable fields converted from rice-wheat rotation fields.

PubMed

Xu, L Y; Wang, M Y; Shi, X Z; Yu, Q B; Shi, Y J; Xu, S X; Sun, W X

2018-08-01

The shift from rice-wheat rotation (RWR) to greenhouse vegetable soils has been widely practiced in China. Several studies have discussed the changes in soil properties with land-use changes, but few studies have sought to address the differences in soil pore properties, especially for fields based on long-term organic fertilization under greenhouse vegetable system from RWR fields. This study uses the X-ray computed tomography (CT) scanning and statistical analysis to compare the long-term effects of the conversion of organic greenhouse vegetable fields (over one year, nine years, and fourteen years) from RWR fields on the soil macropore structure as well as the influencing factors from samples obtained in Nanjing, Jiangsu, China, using the surface soil layer and triplicate samples. The results demonstrated that the macropore structure became more complex and stable, with a higher connectivity, fractal dimension (FD) and a lower degree of anisotropy (DA), as the greenhouse vegetable planting time increased. The total topsoil macroporosity increased considerably, but the rate of increase gradually decelerated with time. The transmission pores (round pores ranging from 50 to 500μm) increased with time, but the biopores (>2000μm) clearly decreased after nine years of use as greenhouse vegetable fields. Soil organic matter (OM) has a significant relationship with the soil pore structure characteristics, especially for the transmission pores. In addition, organic fertilization on the topsoil had a short-term effect on the pores, but the effect stabilized and had a weak influence on the pores over longer periods. These results suggested that organic fertilization was conducive for controlling soil degradation regarding it physical quality for water and oxygen availability in the short term. Copyright © 2018 Elsevier B.V. All rights reserved.

Effects of Soil Organic Matter Properties and Microbial Community Composition on Enzyme Activities in Cryoturbated Arctic Soils

PubMed Central

Schnecker, Jörg; Wild, Birgit; Hofhansl, Florian; Eloy Alves, Ricardo J.; Bárta, Jiří; Čapek, Petr; Fuchslueger, Lucia; Gentsch, Norman; Gittel, Antje; Guggenberger, Georg; Hofer, Angelika; Kienzl, Sandra; Knoltsch, Anna; Lashchinskiy, Nikolay; Mikutta, Robert; Šantrůčková, Hana; Shibistova, Olga; Takriti, Mounir; Urich, Tim; Weltin, Georg; Richter, Andreas

2014-01-01

Enzyme-mediated decomposition of soil organic matter (SOM) is controlled, amongst other factors, by organic matter properties and by the microbial decomposer community present. Since microbial community composition and SOM properties are often interrelated and both change with soil depth, the drivers of enzymatic decomposition are hard to dissect. We investigated soils from three regions in the Siberian Arctic, where carbon rich topsoil material has been incorporated into the subsoil (cryoturbation). We took advantage of this subduction to test if SOM properties shape microbial community composition, and to identify controls of both on enzyme activities. We found that microbial community composition (estimated by phospholipid fatty acid analysis), was similar in cryoturbated material and in surrounding subsoil, although carbon and nitrogen contents were similar in cryoturbated material and topsoils. This suggests that the microbial community in cryoturbated material was not well adapted to SOM properties. We also measured three potential enzyme activities (cellobiohydrolase, leucine-amino-peptidase and phenoloxidase) and used structural equation models (SEMs) to identify direct and indirect drivers of the three enzyme activities. The models included microbial community composition, carbon and nitrogen contents, clay content, water content, and pH. Models for regular horizons, excluding cryoturbated material, showed that all enzyme activities were mainly controlled by carbon or nitrogen. Microbial community composition had no effect. In contrast, models for cryoturbated material showed that enzyme activities were also related to microbial community composition. The additional control of microbial community composition could have restrained enzyme activities and furthermore decomposition in general. The functional decoupling of SOM properties and microbial community composition might thus be one of the reasons for low decomposition rates and the persistence of 400 Gt carbon stored in cryoturbated material. PMID:24705618

The growth of pines germinated from woodchip mulch in restored soils from semiarid SE Spain quarries is enhanced by organic amendments

NASA Astrophysics Data System (ADS)

Luna Ramos, Lourdes; Miralles, Isabel; Lázaro-Suau, Roberto; Solé-Benet, Albert

2017-04-01

The use of pine woodchips in soil restoration in calcareous quarries is a relatively low-cost mulching technique to improve soil water conservation and decrease soil erosion, contributing to improve soil quality. Besides these two important effects, woodchip mulch is also a potential source of seeds which can germinate if environmental conditions during earlier stages are adequate. Pine germination has been observed in experimental plots treated with pine woodchips used as mulch in one of the driest regions in Europe (SE Spain). This side-effect provided an interesting opportunity to analyse the influence of topsoil and two organic wastes (compost from domestic organic waste and sewage sludge from urban water treatment plant) in mine soils on the germinated pines (Pinus halepensis Mill.) and the plant cover (revegetated native plants and spontaneous vegetation). Number, height and basal diameter of pines and the total plant cover were measured 6 years after the applications of topsoil and organic amendments. Results showed that organic wastes increased the pine growth and the total plant cover which could favour in turn the physico-chemical soil properties and its quality in the medium-long term. However, organic amendments negatively influencing the number of germinated pines. The likely growth of pine seedlings derived from the pine cones which come with pine woodchips used as mulch, when enhanced by organic amendments, adds a positive value in quarry restoration even under very dry climatic conditions. However, it is necessary to continue monitoring the development of vegetation to form a more precise idea about whether the development of the pines is globally beneficial, since the pines could outcompete the local native plants.

Colonization and community structure of arbuscular mycorrhizal fungi in maize roots at different depths in the soil profile respond differently to phosphorus inputs on a long-term experimental site.

PubMed

Wang, Chao; White, Philip J; Li, Chunjian

2017-05-01

Effects of soil depth and plant growth stages on arbuscular mycorrhizal fungal (AMF) colonization and community structure in maize roots and their potential contribution to host plant phosphorus (P) nutrition under different P-fertilizer inputs were studied. Research was conducted on a long-term field experiment over 3 years. AMF colonization was assessed by AM colonization rate and arbuscule abundances and their potential contribution to host P nutrition by intensity of fungal alkaline phosphatase (ALP)/acid phosphatase (ACP) activities and expressions of ZmPht1;6 and ZmCCD8a in roots from the topsoil and subsoil layer at different growth stages. AMF community structure was determined by specific amplification of 18S rDNA. Increasing P inputs up to 75-100 kg ha -1  yr -1 increased shoot biomass and P content but decreased AMF colonization and interactions between AMF and roots. AM colonization rate, intensity of fungal ACP/ALP activities, and expression of ZmPht1;6 in roots from the subsoil were greater than those from topsoil at elongation and silking but not at the dough stage when plants received adequate or excessive P inputs. Neither P input nor soil depth influenced the number of AMF operational taxonomic units (OTUs) present in roots, but P-fertilizer input, in particular, influenced community composition and relative AMF abundance. In conclusion, although increasing P inputs reduce AMF colonization and influence AMF community structure, AMF can potentially contribute to plant P nutrition even in well-fertilized soils, depending on the soil layer in which roots are located and the growth stage of host plants.

Applications of stochastic models and geostatistical analyses to study sources and spatial patterns of soil heavy metals in a metalliferous industrial district of China.

PubMed

Zhong, Buqing; Liang, Tao; Wang, Lingqing; Li, Kexin

2014-08-15

An extensive soil survey was conducted to study pollution sources and delineate contamination of heavy metals in one of the metalliferous industrial bases, in the karst areas of southwest China. A total of 597 topsoil samples were collected and the concentrations of five heavy metals, namely Cd, As (metalloid), Pb, Hg and Cr were analyzed. Stochastic models including a conditional inference tree (CIT) and a finite mixture distribution model (FMDM) were applied to identify the sources and partition the contribution from natural and anthropogenic sources for heavy metal in topsoils of the study area. Regression trees for Cd, As, Pb and Hg were proved to depend mostly on indicators of anthropogenic activities such as industrial type and distance from urban area, while the regression tree for Cr was found to be mainly influenced by the geogenic characteristics. The FMDM analysis showed that the geometric means of modeled background values for Cd, As, Pb, Hg and Cr were close to their background values previously reported in the study area, while the contamination of Cd and Hg were widespread in the study area, imposing potentially detrimental effects on organisms through the food chain. Finally, the probabilities of single and multiple heavy metals exceeding the threshold values derived from the FMDM were estimated using indicator kriging (IK) and multivariate indicator kriging (MVIK). The high probabilities exceeding the thresholds of heavy metals were associated with metalliferous production and atmospheric deposition of heavy metals transported from the urban and industrial areas. Geostatistics coupled with stochastic models provide an effective way to delineate multiple heavy metal pollution to facilitate improved environmental management. Copyright © 2014 Elsevier B.V. All rights reserved.

Mercury in forest mushrooms and topsoil from the Yunnan highlands and the subalpine region of the Minya Konka summit in the Eastern Tibetan Plateau.

PubMed

Falandysz, Jerzy; Saba, Martyna; Liu, Hong-Gao; Li, Tao; Wang, Ji-Peng; Wiejak, Anna; Zhang, Ji; Wang, Yuan-Zhong; Zhang, Dan

2016-12-01

This study aimed to investigate and discuss the occurrence and accumulation of mercury in the fruiting bodies of wild-growing fungi (Macromycetes) collected from montane forests in two regions of southwestern China with differences in soil geochemistry, climate and geographical conditions. Fungal mycelia in soils of the subalpine region of the Minya Konka (Gongga Mountain) in Sichuan and in the highlands of Yunnan efficiently accumulated mercury in fruiting bodies (mushrooms). The examined sites in Yunnan with highly mineralized red and yellow soils showed Hg contents ranging from 0.066 to 0.28 mg kg -1 dry biomass (db) which is roughly similar to the results obtained for samples collected from sites with dark soils relatively rich in organic matter from a remote, the subalpine region of Minya Konka. Due to the remoteness of the subalpine section of Minya Konka, as well as its elevation and climate, airborne mercury from long-range transport could be deposited preferentially on the topsoil and the Hg levels determined in soil samples taken beneath the fruiting bodies were up to 0.48 mg kg -1 dry matter. In Yunnan, with polymetallic soils (Circum-Pacific Mercuriferous Belt), Amanita mushrooms showed mercury in caps of fruiting bodies of up to 7.3 mg kg -1 dry biomass. Geogenic Hg from the mercuriferous belt seems to be the overriding source of mercury accumulated in mushrooms foraged in the regions of Yunnan, while long-range atmospheric transport and subsequent deposition are the mercury sources for specimens foraged in the region of Minya Konka.

Thermal shock and splash effects on burned gypseous soils from the Ebro Basin (NE Spain)

NASA Astrophysics Data System (ADS)

León, J.; Seeger, M.; Badía, D.; Peters, P.; Echeverría, M. T.

2014-03-01

Fire is a natural factor of landscape evolution in Mediterranean ecosystems. The middle Ebro Valley has extreme aridity, which results in a low plant cover and high soil erodibility, especially on gypseous substrates. The aim of this research is to analyze the effects of moderate heating on physical and chemical soil properties, mineralogical composition and susceptibility to splash erosion. Topsoil samples (15 cm depth) were taken in the Remolinos mountain slopes (Ebro Valley, NE Spain) from two soil types: Leptic Gypsisol (LP) in a convex slope and Haplic Gypsisol (GY) in a concave slope. To assess the heating effects on the mineralogy we burned the soils at 105 and 205 °C in an oven and to assess the splash effects we used a rainfall simulator under laboratory conditions using undisturbed topsoil subsamples (0-5 cm depth of Ah horizon). LP soil has lower soil organic matter (SOM) and soil aggregate stability (SAS) and higher gypsum content than GY soil. Gypsum and dolomite are the main minerals (>80%) in the LP soil, while gypsum, dolomite, calcite and quartz have similar proportions in GY soil. Clay minerals (kaolinite and illite) are scarce in both soils. Heating at 105 °C has no effect on soil mineralogy. However, heating to 205 °C transforms gypsum to bassanite, increases significantly the soil salinity (EC) in both soil units (LP and GY) and decreases pH only in GY soil. Despite differences in the content of organic matter and structural stability, both soils show no significant differences (P < 0.01) in the splash erosion rates. The size of pores is reduced by heating, as derived from variations in soil water retention capacity.

Use of stable isotopes of carbon, nitrogen, and sulfer to identify sources of nitrogen in surface waters in the Lower Susquehanna River basin, Pennsylvania

USGS Publications Warehouse

Cravotta, C.A.

1995-01-01

Stable isotopes of carbon (C), nitrogen (N), and sulfur (S) in nitrogen sources and nearby samples of topsoil, subsoil, runoff water, and stream water were measured to evaluate the feasibility of using isotopic data to identify nitrogen sources in stream water from forested, agricultural, or suburban land-use areas. Chemical and isotopic compositions were measured for six N-source types consisting of rain water, forest-leaf litter, synthetic fertilizer, farm-animal manure, municipal-sewage effluent and sludge, and septic-tank effluent and sludge. Compositions of topsoil, subsoil, runoff water, and stream water were measured to evaluate changes in compositions of transported N-containing materials near the N source. Animal manure, human waste (sewage plus septic), and forest-leaf litter can be distinguished on the basis of C; however, most N-sources can not be distinguished on the basis of N and S, owing to wide ranges of compositions and overlap among different N-source types. Although values of N for soil and runoff-water samples are qualitatively similar to those of the applied N source, values of C and S for runoff-water and stream-water samples appear to reflect the compositions of relatively large reservoirs of the elements in soil organic matter and minerals, respectively, and not the composition of the applied N source. Because of incomplete chemical transfor- mations, the ratio of organic carbon to total nitrogen for particulates in runoff or stream waters generally is lower than that for associated, nearby soils, and isotopic compositions commonly differ between particulate and dissolved fractions in the water.

Geochemical properties of topsoil around the coal mine and thermoelectric power plant.

PubMed

Stafilov, Trajče; Šajn, Robert; Arapčeska, Mila; Kungulovski, Ivan; Alijagić, Jasminka

2018-03-19

The results of the systematic study of the spatial distribution of trace metals in surface soil over the Bitola region, Republic of Macedonia, known for its coal mine and thermo-electrical power plant activities are reported. The investigated region (3200 km 2 ) is covered by a sparse sampling grid of 5 × 5 km, but in the urban zone and around the thermoelectric power plant the sampling grid is denser (1 × 1 km). In total, 229 soil samples from 149 locations were collected including top-soil (0-5 cm) and bottom-soil samples (20-30 cm and 0-30 cm). Inductively coupled plasma - atomic emission spectrometry (ICP-AES) was applied for the determinations of 21 elements (Al, As, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, P, Pb, Sr, V and Zn). Based on the results of factor analyses, three geogenic associations of elements have been defined: F1 (Fe, Ni, V, Co, Cr, Mn and Li), F2 (Zn, B, Cu, Cd, Na and K) and F3 (Ca, Sr, Mg, Ba and Al). Even typical trace metals such as As, Cd, Cu, Ni, P, Pb and Zn are not isolated into anthropogenic geochemical associations by multivariate statistical methods still show some trends of local anthropogenic enrichment. The distribution maps for each analyzed element is showing the higher content of these elements in soil samples collected around the thermoelectric power plants than their average content for the soil samples collected from the whole Bitola Region. It was found that this enrichment is a result of the pollution by fly ash from coal burning which deposited near the plant having a high content of these elements.

Comparison of soil organic carbon speciation using C NEXAFS and CPMAS 13C NMR spectroscopy.

PubMed

Prietzel, Jörg; Müller, Svenja; Kögel-Knabner, Ingrid; Thieme, Jürgen; Jaye, Cherno; Fischer, Daniel

2018-07-01

We compared synchrotron-based C near-edge X-ray absorption fine structure (NEXAFS) and CPMAS 13 C nuclear magnetic resonance (NMR) spectroscopy with respect to their precision and accuracy to quantify different organic carbon (OC) species in defined mixtures of soil organic matter source compounds. We also used both methods to quantify different OC species in organic surface horizons of a Histic Leptosol as well as in mineral topsoil and subsoil horizons of two soils with different parent material, stage of pedogenesis, and OC content (Cambisol: 15-30 OC mgg -1 , Podzol: 0.9-7 OC mgg -1 ). CPMAS 13 C NMR spectroscopy was more accurate and precise (mean recovery of different C functional groups 96-103%) than C NEXAFS spectroscopy (mean recovery 92-113%). For organic surface and topsoil samples, NMR spectroscopy consistently yielded larger O-alkyl C percentages and smaller alkyl C percentages than C NEXAFS spectroscopy. For the Cambisol subsoil samples both methods performed well and showed similar C speciation results. NEXAFS spectroscopy yielded excellent spectra with a high signal-to-noise ratio also for OC-poor Podzol subsoil samples, whereas this was not the case for CPMAS 13 C NMR spectroscopy even after sample treatment with HF. Our results confirm the analytical power of CPMAS 13 C NMR spectroscopy for a reliable quantitative OC speciation in soils with >10mgOCg -1 . Moreover, they highlight the potential of synchrotron-based C NEXAFS spectroscopy as fast, non-invasive method to semi-quantify different C functional groups in soils with low C content (0.9-10mgg -1 ). Copyright © 2018 Elsevier B.V. All rights reserved.

Distribution of enzyme activity hotspots induced by earthworms in top- and subsoil

NASA Astrophysics Data System (ADS)

Hoang, D. T. T.

2016-12-01

Earthworms (Lumbricus terrestris L.) not only affect soil physics, but they also boost microbial activities and consequently create important hotspots of microbial mediated carbon and nutrient turnover through their burrowing activity. However, it is still unknown to which extend earthworms change the enzyme distribution and activity inside their burrows in top- and subsoil horizons. We hypothesized that earthworm burrows, which are enriched in available substrates, have higher percentage of enzyme activity hotspots than soil without earthworms, and that enzyme activities decreased with increasing depth because of the increasing recalcitrance of organic matter in subsoil. We visualized enzyme distribution inside and outside of worm burrows (biopores) by in situ soil zymography and measured enzyme kinetics of 6 enzymes - β-glucosidase (GLU), cellobiohydrolase (CBH), xylanase (XYL), chitinase (NAG), leucine aminopeptidase (LAP) and acid phosphatase (APT) - in pore and bulk soil material up to 105 cm. Zymography showed a heterogeneous distribution of hotspots in worm burrows. The hotspot areas was 2.4 to 14 times larger in the burrows than in soil without earthworms. However, the dispersion index of hotspot distribution showed more aggregated hotspots in soil without earthworms than in soil with earthworms and burrow wall. Enzyme activities decreased with depth, by a factor of 2 to 8 due to fresh C input from the soil surface. Compared to bulk soil, enzyme activities in topsoil biopores were up to 11 times higher for all enzymes, but in the subsoil activities of XYL, NAG and APT were lower in earthworm biopores than bulk soil. In conclusion, hotspots were twice as concentrated close to earthworm burrows as in surrounding soil. Earthworms exerted stronger effects on enzyme activities in biopores in the topsoil than in subsoil. Keywords: Earthworms, hotspots, enzyme activities, enzyme distribution, subsoil

The Effects of Plastic Film Mulching on Maize Growth and Water Use in Dry and Rainy Years in Northeast China

PubMed Central

Xu, Jie; Li, Congfeng; Liu, Huitao; Zhou, Peilu; Tao, Zhiqiang; Wang, Pu; Meng, Qingfeng; Zhao, Ming

2015-01-01

Plastic film mulching (PM) has been widely used to improve maize (Zea mays L.) yields and water use efficiency (WUE) in Northeast China, but the effects of PM in a changing climate characterized by highly variable precipitation are not well understood. Six site-year field experiments were conducted in the dry and rainy years to investigate the effects of PM on maize growth, grain yield, and WUE in Northeast China. Compared to crops grown without PM treatment (control, CK), PM significantly increased the grain yield by 15-26% in the dry years, but no significant yield increase was observed in the rainy years. Yield increase in the dry years was mainly due to a large increase in dry matter accumulation pre-silking compared to the CK, which resulted from a greater dry matter accumulation rate due to the higher topsoil temperature and water content. As a result, the WUE of the crops that underwent PM (3.27 kg m-3) treatment was also increased by around 16% compared to the CK, although the overall evapotranspiration was similar between the two treatments. In the rainy years, due to frequent precipitation and scant sunshine, the topsoil temperature and water content in the field that received PM treatment was improved only at some stages and failed to cause higher dry matter accumulation, except at the 8th leaf stage. Consequently, the grain yield and WUE were not improved by PM in the rainy years. In addition, we found that PM caused leaf senescence at the late growth stage in both dry and rainy years. Therefore, in practice, PM should be applied cautiously, especially when in-season precipitation is taken into account. PMID:25970582

Highway increases concentrations of toxic metals in giant panda habitat.

PubMed

Zheng, Ying-Juan; Chen, Yi-Ping; Maltby, Lorraine; Jin, Xue-Lin

2016-11-01

The Qinling panda subspecies (Ailuropoda melanoleuca qinlingensis) is highly endangered with fewer than 350 individuals inhabiting the Qinling Mountains. Previous studies have indicated that giant pandas are exposed to heavy metals, and a possible source is vehicle emission. The concentrations of Cu, Zn, Mn, Pb, Cr, Ni, Cd, Hg, and As in soil samples collected from sites along a major highway bisecting the panda's habitat were analyzed to investigate whether the highway was an important source of metal contamination. There were 11 sites along a 30-km stretch of the 108th National Highway, and at each site, soil samples were taken at four distances from the highway (0, 50, 100, and 300 m) and at three soil depths (0, 5, 10 cm). Concentrations of all metals except As exceeded background levels, and concentrations of Cu, Zn, Mn, Pb, and Cd decreased significantly with increasing distance from the highway. Geo-accumulation index indicated that topsoil next to the highway was moderately contaminated with Pb and Zn, whereas topsoil up to 300 m away from the highway was extremely contaminated with Cd. The potential ecological risk index demonstrated that this area was in a high degree of ecological hazards, which were also due to serious Cd contamination. And, the hazard quotient indicated that Cd, Pb, and Mn especially Cd could pose the health risk to giant pandas. Multivariate analyses demonstrated that the highway was the main source of Cd, Pb, and Zn and also put some influence on Mn. The study has confirmed that traffic does contaminate roadside soils and poses a potential threat to the health of pandas. This should not be ignored when the conservation and management of pandas is considered.

Distribution, source analysis, and ecological risk assessment of polycyclic aromatic hydrocarbons in the typical topsoil of the Issyk-Kul Lake Basin.

PubMed

Liu, Wen; Ma, Long; Abuduwaili, Jilili; Li, Yaoming

2017-08-01

The concentration, distribution, compositional characteristics, and pollution sources of 16 polycyclic aromatic hydrocarbons (PAHs) in the topsoil of Issyk-Kul Lake Basin were studied, and their ecological risks were evaluated in this paper. The total concentration of the 16 PAHs was 68.58-475.95 ng g -1 , with an average of 134.45 ng g -1 . Four-ring PAHs accounted for 43.2% of the total PAHs, two- and three-ring PAHs accounted for 39.4%, and five- and six-ring PAHs accounted for 15.8%. The total concentration of the seven carcinogenic PAHs was 7.66-76.04 ng g -1 , with an average of 30.97 ng g -1 . An analysis of the PAH sources through diagnostic ratio analysis and principal component analysis was carried out. The results showed that the regional soil PAHs were mainly derived from coal, wood, and grass combustion, while traffic and regional industry also had small contributions to the PAHs. The pollution-free samples accounted for 75% and the slightly polluted samples accounted for 25% based on the total concentration of the 16 PAHs. An ecological risk assessment showed that 26.7% of Ac and 3.3% of Pyr and DahA might occasionally produce ecological risks. The toxicity was calculated on the basis of benzo[a]pyrene, and the toxicity equivalent was between 2.48 and 13.78 ng g -1 with an average of 6.23 ng g -1 , which currently does not pose any health risk to human life.

Is the detection of aquatic environmental DNA influenced by substrate type?

PubMed

Buxton, Andrew S; Groombridge, Jim J; Griffiths, Richard A

2017-01-01

The use of environmental DNA (eDNA) to assess the presence-absence of rare, cryptic or invasive species is hindered by a poor understanding of the factors that can remove DNA from the system. In aquatic systems, eDNA can be transported out either horizontally in water flows or vertically by incorporation into the sediment. Equally, eDNA may be broken down by various biotic and abiotic processes if the target organism leaves the system. We use occupancy modelling and a replicated mesocosm experiment to examine how detection probability of eDNA changes once the target species is no longer present. We hypothesise that detection probability falls faster with a sediment which has a large number of DNA binding sites such as topsoil or clay, over lower DNA binding capacity substrates such as sand. Water removed from ponds containing the target species (the great crested newt) initially showed high detection probabilities, but these fell to between 40% and 60% over the first 10 days and to between 10% and 22% by day 15: eDNA remained detectable at very low levels until day 22. Very little difference in detection was observed between the control group (no substrate) and the sand substrate. A small reduction in detection probability was observed between the control and clay substrates, but this was not significant. However, a highly significant reduction in detection probability was observed with a topsoil substrate. This result is likely to have stemmed from increased levels of PCR inhibition, suggesting that incorporation of DNA into the sentiment is of only limited importance. Surveys of aquatic species using eDNA clearly need to take account of substrate type as well as other environmental factors when collecting samples, analysing data and interpreting the results.

Pesticide leaching from two Swedish topsoils of contrasting texture amended with biochar

NASA Astrophysics Data System (ADS)

Larsbo, Mats; Löfstrand, Elisabeth; de Veer, David van Alphen; Ulén, Barbro

2013-04-01

The use of biochar as a soil amendment has recently increased because of its potential for long-term soil carbon sequestration and its potential for improving soil fertility. The objective of this study was to quantify the effects of biochar soil incorporation on pesticide adsorption and leaching for two Swedish topsoils, one clay soil and one loam soil. We used the non-reactive tracer bromide and the pesticides sulfosulfuron, isoproturon, imidacloprid, propyzamid and pyraclostrobin, substances with different mobility in soil. Adsorption was studied in batch experiments and leaching was studied in experiments using soil columns (20 cm high, 20 cm diameter) where 0.01 kg kg- 1 dw biochar powder originating from wheat residues had been mixed into the top 10 cm. After solute application the columns were exposed to simulated rain three times with a weekly interval and concentrations were measured in the effluent water. The biochar treatment resulted in significantly larger adsorption distribution coefficients (Kd) for the moderately mobile pesticides isoproturon and imidacloprid for the clay soil and for imidacloprid only for the loam soil. Relative leaching of the pesticides ranged from 0.0035% of the applied mass for pyraclostrobin (average Kd = 360 cm3 g- 1) to 5.9% for sulfosulfuron (average Kd = 5.6 cm3 g- 1). There were no significant effects of the biochar amendment on pesticide concentrations in column effluents for the loam soil. For the clay soil concentrations were significantly reduced for isoproturon, imidacloprid and propyzamid while they were significantly increased for the non-mobile fungicide pyraclostrobin suggesting that the transport was facilitated by material originating from the biochar amendment.

Simultaneous sorption of four ionizable pharmaceuticals in different horizons of three soil types.

PubMed

Kočárek, Martin; Kodešová, Radka; Vondráčková, Lenka; Golovko, Oksana; Fér, Miroslav; Klement, Aleš; Nikodem, Antonín; Jakšík, Ondřej; Grabic, Roman

2016-11-01

Soils may be contaminated by human or veterinary pharmaceuticals. Their behaviour in soil environment is largely controlled by sorption of different compounds in a soil solution onto soil constituents. Here we studied the sorption affinities of 4 pharmaceuticals (atenolol, trimethoprim, carbamazepine and sulfamethoxazole) applied in solute mixtures to soils taken from different horizons of 3 soil types (Greyic Phaeozem on loess, Haplic Luvisol on loess and Haplic Cambisol on gneiss). In the case of the carbamazepine (neutral form) and sulfamethoxazole (partly negatively charged and neutral), sorption affinity of compounds decreased with soil depth, i.e. decreased with soil organic matter content. On the other hand, in the case of atenolol (positively charged) and trimethoprim (partly positively charged and neutral) compound sorption affinity was not depth dependent. Compound sorption affinities in the four-solute systems were compared with those experimentally assessed in topsoils, and were estimated using the pedotransfer rules proposed in our previous study for single-solute systems. While sorption affinities of trimethoprim and carbamazepine in topsoils decreased slightly, sorption affinity of sulfamethoxazole increased. Decreases in sorption of the two compounds could be attributed to their competition between each other and competition with atenolol. Differences between carbamazepine and atenolol behaviour in the one- and four-solute systems could also be explained by the slightly different soil properties in this and our previous study. A great increase of sulfamethoxazole sorption in the Greyic Phaeozem and Haplic Luvisol was observed, which was attributed to elimination of repulsion between negatively charged molecules and particle surfaces due to cation sorption (atenolol and trimethoprim) on soil particles. Thus, our results proved not only an antagonistic but also a synergic affect of differently charged organic molecules on their sorption to soil constituents. Copyright © 2016 Elsevier Ltd. All rights reserved.

Heavy metals pollution levels and children health risk assessment of Yerevan kindergartens soils.

PubMed

Tepanosyan, Gevorg; Maghakyan, Nairuhi; Sahakyan, Lilit; Saghatelyan, Armen

2017-08-01

Children, the most vulnerable urban population group, are exceptionally sensitive to polluted environments, particularly urban soils, which can lead to adverse health effects upon exposure. In this study, the total concentrations of Ag, As, Ba, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Ti, V, and Zn were determined in 111 topsoil samples collected from kindergartens in Yerevan. The objectives of this study were to evaluate heavy metal pollution levels of kindergarten's soils in Yerevan, compare with national legal and international requirements on heavy metal contents in kindergarten soil, and assess related child health risk. Multivariate geostatistical analyses suggested that the concentrations of Ag, As, Ba, Cd, Cu, Hg, Mo, Pb, and Zn observed in the kindergarten's topsoil may have originated from anthropogenic sources, while Co, Cr, Fe, Mn, Ni, Ti, and V mostly come from natural sources. According to the Summary pollution index (Zc), 102 kindergartens belong to the low pollution level, 7 to the moderate and only 2 to the high level of pollution. Summary concentration index (SCI) showed that 109 kindergartens were in the allowable level, while 2 featured in the low level of pollution. The health risk assessment showed that in all kindergartens except for seven, non-carcinogenic risk for children was detected (HI>1), while carcinogenic risk from arsenic belongs to the very low (allowable) level. Cr and multi-element carcinogenic risk (RI) exceeded the safety level (1.0E- 06) in all kindergartens and showed that the potential of developing cancer, albeit small, does exist. Therefore, city's kindergartens require necessary remedial actions to eliminate or reduce soil pollution and heavy metal-induced health risks. Copyright © 2017 Elsevier Inc. All rights reserved.

Monitoring of Soil Contamination by Heavy Metals in the Impact Zone of Copper-Nickel Smelter on the Kola Peninsula

NASA Astrophysics Data System (ADS)

Kashulina, G. M.

2018-04-01

The results of landscape monitoring of the concentrations of acid-extractable Ni, Cu, Co, Mn, and Zn in soils of the local impact zone of the Severonikel industrial complex on the Kola Peninsula are discussed. The aim of monitoring studies was to reveal the spatial and temporal regularities of variation in the degree of soil contamination by heavy metals. In 2001-2011, the concentrations of acid-extractable compounds of the elements in the upper part of organic soil horizons around this plant exceeded their background concentrations by two orders of magnitude for Cu and Co and by three orders of magnitude for Ni. The degree of topsoil contamination with Ni, Cu, and Co generally corresponded to the distance of the plots from the contamination source and to the modern technogenic load. However, because of the long period of the emissions, their extreme amounts, and complex composition, indirect factors—the degree of technogenic soil degradation, the loss of soil organic matter, saturation of the surface soil layers by the contaminating metals, and competitive relationships between the elements—also affect soil contamination level. The concentrations of all the studied metals in the topsoil are characterized by considerable (1.5 to 7 times) variability in their long-term dynamics. The most important factors of this variability for Ni, Cu, and Co are the organic matter content of the samples and the amount of atmospheric precipitation in the year preceding the sampling. An inverse relationship between element concentrations in the soils and the amount of atmospheric precipitation attests to the dynamic nature and reversible character of the accumulation of heavy metals in the soils.

Deforestation and cultivation mobilize mercury from topsoil.

PubMed

Gamby, Rebecca L; Hammerschmidt, Chad R; Costello, David M; Lamborg, Carl H; Runkle, James R

2015-11-01

Terrestrial biomass and soils are a primary global reservoir of mercury (Hg) derived from natural and anthropogenic sources; however, relatively little is known about the fate and stability of Hg in the surface soil reservoir and its susceptibility to change as a result of deforestation and cultivation. In southwest Ohio, we measured Hg concentrations in soils of deciduous old- and new-growth forests, as well as fallow grassland and agricultural soils that had once been forested to examine how, over decadal to century time scales, man-made deforestation and cultivation influence Hg mobility from temperate surface soils. Mercury concentrations in surficial soils were significantly greater in the old-growth than new-growth forest, and both forest soils had greater Hg concentrations than cultivated and fallow fields. Differences in Hg:lead ratios between old-growth forest and agricultural topsoils suggest that about half of the Hg lost from deforested and cultivated Ohio soils may have been volatilized and the other half eroded. The estimated mobilization potential of Hg as a result of deforestation was 4.1 mg m(-2), which was proportional to mobilization potentials measured at multiple locations in the Amazon relative to concentrations in forested surface soils. Based on this relationship and an estimate of the global average of Hg concentrations in forested soils, we approximate that about 550 M mol of Hg has been mobilized globally from soil as a result of deforestation during the past two centuries. This estimate is comparable to, if not greater than, the amount of anthropogenic Hg hypothesized by others to have been sequestered by the soil reservoir since Industrialization. Our results suggest that deforestation and soil cultivation are significant anthropogenic processes that exacerbate Hg mobilization from soil and its cycling in the environment. Copyright © 2015 Elsevier B.V. All rights reserved.

Finding of No Significant Impact: Environmental Assessment Construction of Hangar Addition Building 820 Tinker Air Force Base, Oklahoma

DTIC Science & Technology

2012-03-06

and topsoil cover was constructed over the trenched art::a in August 1990, the landfill wa’i capped in 1998 to 1999, and long-tt::rm groundwater...Controls and Continuous Me tering, February 20 12 ~ - 12 • • • • /,1/l//"fii/111(𔃻/(CI/ ·fs.\\t’.H/1/1’//l L"nnronmcntal Comt •quenu’ • Energy...lnstmction 9 1-202, The U.S. Air Force Mishap Prevention Program, August . USAF. 20 I 0. U nited States Air Force. Spill Pre,•ention and Emergency Response

Installation Restoration Program. Phase II. Confirmation/Quantification. Stage 1. Volume 2. Appendices A-M. Cannon AFB, New Mexico.

DTIC Science & Technology

1986-09-01

0’ - N tT qT -0 t" C-r C-, M z a <CLW 4 0 a. o.CL- C= un z LJJIIr-= r -I CiA c= cot ’ rcli LAJI LUU CLCL LLI- IOUa a. IF LLJLm I-l - ( Cft - 4 CL...Depth Graphic Core Sample Sample Cft ) Log Interval/ID Taken* Lithologic Description 0- .. ~.G TOPSOIL; with some wood and other debris. 5-.~J SB-lA-1 ST...Date Recev 7 T ime~ L Transported By La- aml No. 0,; 0 Comments_____________________ ________ ___ Inclusive Dates of Possession

Microbial N and P mining regulates the effect of N deposition on soil organic matter turnover

NASA Astrophysics Data System (ADS)

Meyer, Nele; Welp, Gerhard; Rodionov, Andrei; Borchard, Nils; Martius, Christopher; Amelung, Wulf

2017-04-01

Nitrogen (N) deposition to soils has become a global issue during the last decades. Its effect on mineralization of soil organic carbon (SOC), however, is still debated. Common theories based on Liebig's law predict higher SOC mineralization rates in nutrient-rich than in nutrient-poor soils. Contrastingly, the concept of microbial N mining predicts lower mineralization rates after N deposition. The latter is explained by ceased decomposition of recalcitrant soil organic matter (SOM) as the need of microbes to acquire N from this pool decreases. As N deposition might shift the nutrient balance towards relative phosphorus (P) deficiency, it is also necessary to consider P mining in this context. Due to limited knowledge about microbial nutrient mining, any predictions of N deposition effects are difficult. This study aims at elucidating the preconditions under which microbial nutrient mining occurs in soil. We hypothesized that the occurrence of N and P mining is controlled by the current nutrient status of the soil. Likewise, soils might respond differently to N additions. To investigate this hypothesis, we conducted substrate-induced respiration measurements on soils with pronounced gradients of N and P availability. We used topsoil samples taken repeatedly from a site which was up to 7 years under bare fallow (Selhausen, Germany) and up to 4 m deep tropical forest soils (Kalimantan, Indonesia). Additional nutrient manipulations (glucose, glucose+N, glucose+P, glucose+N+P additions) were conducted to study the effect of nutrient additions. Samples were incubated for one month. We further conducted 13C labeling experiments to trace the sources of CO2 (sugar vs. SOM derived CO2) for further hints on nutrient mining. Mineralization of glucose was limited by a lack of available N in the bare fallow soil but microbes were able to slowly acquire N from previously unavailable pools. This resulted in a slightly higher release of native SOM-derived CO2 compared to N-fertilized treatments. Nutrient additions had no effect on cumulative CO2 evolution in tropical topsoils. Subsoils of the tropical sites (20 - 100 cm depth) were co-limited by N and P. Here, alleviation of either N or P deficiency was necessary to stimulate the mineralization of glucose. In the deep subsoil (>150 cm depth) only the combined additions of N+P induced any CO2 release. Our results reveal that mining of both N and P potentially occurs but is restricted by multiple nutrient limitations, by the absence of potentially accessible nutrients (e.g., in the deep subsoil), and by full nutrient supply (e.g., high nutrient contents make mining unnecessary). The results suggest several implications for N deposition effects: 1) N deposition decreases (recalcitrant) SOC mineralization in former N-deficient soils, 2) N deposition increases SOC mineralization in former co-limited soils as it facilitates mining of the required P, 3) N deposition has no effect in nutrient rich topsoils.

Woody plant encroachment effect on soil organic carbon dynamics: results from a latitudinal gradient in Italy

NASA Astrophysics Data System (ADS)

Pellis, Guido; Chiti, Tommaso; Moscatelli, Maria Cristina; Marinari, Sara; Papale, Dario

2016-04-01

Woody plant encroachment into pastures and grasslands represents a significant land cover change phenomenon, with a considerable impact on carbon dynamics at an ecosystem level. It was estimated that 7.64% of the Southern Europe land was subject to that process between 1950 to 2010. As a result of woody encroachment, changes in vegetation composition can produce substantial changes to the soil organic carbon (SOC) cycle. Despite the numerous papers published on land-use change, an evaluation of the IPCC terrestrial carbon pools changes occurring during woody encroachment on abandoned pastures and grasslands is still lacking, particularly for the Italian territory. Therefore, the aim of this study was to investigate the role of woody encroachment on carbon sequestration over abandoned pastures and grasslands in Alpine and Apennine ecosystems, with a particular focus on the SOC. We applied a chronosequence approach to seven selected sites located along a latitudinal gradient in Italy. Each chronosequence consisted of a pasture currently managed, three sites abandoned at different times in the past and, finally, a mature forest stand representing the last phase of the succession. The European Commission sampling protocols to certify SOC changes was adopted to estimate the variations following woody encroachment. Soil samples were collected at different depths in the topsoil (0-30 cm) and subsoil (30-70 cm), despite the original protocol formulation being limited to the topsoil only. In addition, aboveground living biomass (AGB), dead wood and litter were also measured following international protocols. Considering all C pools together, woody plant encroachment leads to a progressive C stock accumulation in all the chronosequences. The total C stock of mature forest stands ranges from 1.78±0.11 times (Eastern Alps) to 2.48±0.31 times (central Apennine) the initial value on pastures. Unsurprisingly, the C stocks of AGB, dead wood and litter all increase during the process of woody encroachment. Instead, the SOC dynamics are more complex, as previous studies suggest they are strongly affected by precipitation and temperature. Accordingly, we found that in the Apennine sites, characterised by a Mediterranean mountainous climate, the SOC increased more than 50% from pasture to forest stages. Conversely, the increment appears not or barely statistically significant in the two colder and more humid Eastern Alps sites. Our results also indicate a substantial amount of SOC is stored in the subsoil, despite many existing sampling protocols (including the original form of the one we adopted) typically restrict measurements only to the topsoil. Therefore, it is recommended to measure the SOC along the whole profile to avoid overlooking the significant amount of C that can accumulate in the subsoil during the process of woody encroachment. In conclusion, this study reveals a positive impact of woody encroachment in increasing the C at an ecosystem level and suggests that SOC measurements are extremely important when precise emission-removal estimates due to land use change are required.

Horse paddocks - an emerging source of agricultural water pollution

NASA Astrophysics Data System (ADS)

Masud Parvage, Mohammed; Ulén, Barbro; Kirchmann, Holger

2015-04-01

Horse farms occupy about 4% of the total agricultural land in the EU but are not well investigated with regard to their impact on water quality. Horse paddocks commonly hold horses on a limited space and the animal density often exceeds the recommended density. Therefore, paddock soils receive significant amounts of phosphorus (P) and nitrogen (N) through feed residues and deposition of faeces and urine, which can lead to nutrient build-up in the soil and subsequent losses to aquatic systems. This study characterized the potential risk of phosphorus (P) and nitrogen (N) leaching losses from Swedish horse paddocks through three stage examination of soil and water P and N status. The experiment began with a pilot study where surface soil P status and eight years of drainage P data were examined from a paddock catchment and an adjacent arable catchment both receiving similar amount of P and N over years. Results showed that there were no signi?cant differences in water-soluble P (WSP) or total P data in soils but the drainage water P concentrations, being higher in the paddock catchment (0.33 mg P l-1, mainly in dissolved reactive form) than the arable catchment (0.10 mg P l-1). In the second experiment, soil P and N status were examined in different parts of horse paddocks (feeding, grazing, and excretion areas) to identify existence of any potential hotspots for losses within the paddock. In total, seven horse farms, covering different grazing densities and soil textures representative of Swedish horse paddocks were examined. The results showed that concentrations of WSP, plant available P or P-AL (P extracted in ammonium acetate lactate solution at pH 3.75), and total N were highest in feeding and excretion areas within the paddocks. It was also observed that the WSP concentration in the paddocks was strongly correlated with horse density (R2 = 0.80, p < 0.001) and P-AL with years of paddock management (R2 = 0.78, p < 0.001). In the final experiment, topsoil columns (0-20 cm) from the different segments of the paddock were isolated and potential leaching losses of P, N and carbon (C) were measured from two representative horse paddock (a clay and a loamy sand) following simulated rainfall events in the laboratory. Results showed that the leachate concentrations and net release of P, N, and dissolved organic C (DOC) from paddock topsoils were highest in feeding and excretion areas and considerably higher from the loamy sand than the clay paddock topsoil. It was concluded that: i) horse paddocks pose a potential threat to water quality via leaching of excess P and N, ii) feeding and excretion areas are potential hotspots for highly enhanced leaching losses, and iii) paddocks established on sandy soils are particularly susceptible to high losses.

Spatial and temporal variability of soil hydraulic properties of topsoil affected by soil erosion

NASA Astrophysics Data System (ADS)

Nikodem, Antonin; Kodesova, Radka; Jaksik, Ondrej; Jirku, Veronika; Klement, Ales; Fer, Miroslav

2014-05-01

This study is focused on the comparison of soil hydraulic properties of topsoil that is affected by erosion processes. In order to include variable morphological and soil properties along the slope three sites - Brumovice, Vidim and Sedlčany were selected. Two transects (A, B) and five sampling sites along each one were chosen. Soil samples were taken in Brumovice after the tillage and sowing of winter wheat in October 2010 and after the wheat harvest in August 2011. At locality Vidim and Sedlčany samples were collected in May and August 2012. Soil hydraulic properties were studied in the laboratory on the undisturbed 100-cm3 soil samples placed in Tempe cells using the multi-step outflow test. Soil water retention data points were obtained by calculating water balance in the soil sample at each pressure head step of the experiment. The single-porosity model in HYDRUS-1D was applied to analyze the multi-step outflow and to obtain the parameters of soil hydraulic properties using the numerical inversion. The saturated hydraulic conductivities (Ks) and unsaturated hydraulic conductivities (Kw) for the pressure head of -2 cm of topsoil were also measured after the harvest using Guelph permeameter and Minidisk tensiometer, respectively. In general soil water retention curves measured before and after vegetation period apparently differed, which indicated soil material consolidation and soil-porous system rearrangement. Soil water retention curves obtained on the soil samples and hydraulic conductivities measured in the field reflected the position at the elevation transect and the effect of erosion/accumulation processes on soil structure and consequently on the soil hydraulic properties. The highest Ks values in Brumovice were obtained at the steepest parts of the elevation transects, that have been the most eroded. The Ks values at the bottom parts decreased due to the sedimentation of eroded soil particles. The change of the Kw values along transects didn't show similar trends. However, the variability of values within both transects was low. Higher values were obtained in transect B, where the soil was more affected by erosion. The highest values of Ks as well as the value of Kw were also obtained in the steepest part of transect A in Vidim. This trend was not observed in transect B. The results corresponded with measured retention curves. Two different trends were shown in Sedlčany. While the highest values of Ks and Kw were found in the upper part of transect A, in the case of transect B the highest values were measured at the bottom of transect. Differences observed at both localities were caused by the different terrain attributes of both transects and extent of soil erosion. Acknowledgement: Authors acknowledge the financial support of the Ministry of Agriculture of the Czech Republic (QJ1230319).

Impact of cattle grazing on soil and vegetation - a case study in a mountainous region of Austria

NASA Astrophysics Data System (ADS)

Bohner, Andreas; Foldal, Cecilie; Jandl, Robert

2015-04-01

In mountainous regions of Austria and of many other European countries, climate change may cause a further intensification of grassland management. Therefore, the effects of intensive cattle grazing on selected soil chemical and physical properties, above- and below-ground phytomass, forage quality, plant species composition and plant species richness at the scale of a representative paddock in a mountainous region of Austria were investigated. At the study site (Styrian Enns valley; 675 m a.s.l.), climate is relatively cool and humid, with a mean annual air temperature of 6.7°C and a mean annual precipitation of 970 mm, of which 66% falls during the vegetation period (April-October). The soil is a deep, base-rich Cambisol with a loamy sand texture. The paddock investigated has a total area of about 2 ha and had been grazed by dairy cows (Brown Swiss) five times per grazing season. The stocking density was 4 cows ha-1 during 180 days from early May to the end of October with a grazing time of about 8 hours per day. The strip grazed permanent pasture was manured annually for a long time, mostly with cattle slurry. Vegetation surveys were carried out using the method of Braun-Blanquet. Above- and below-ground phytomass, forage quality and mineral element concentration in the harvestable above-ground plant biomass were determined by using standard methods. During the grazing season surface soil samples (0-10 cm depth) for chemical analyses were collected before each grazing period (5 analyses of composite samples per site). At the beginning and the end of the grazing season also soil samples for physical analyses were taken from the topsoil (0-15 cm depth). Heavy cattle treading led to a substantial soil compaction especially in the 5-10 cm layer and to a deterioration of topsoil structure. The porous crumb structure was replaced by a compact platy structure. The topsoil was enriched with nutrients (mainly nitrogen, potassium, phosphorus and boron). The degree of phosphorus saturation was very high. Consequently, the risk of elevated nutrient losses via leaching and surface runoff is increased. This, in turn, may pose a threat to ground water, surface water and adjacent ecosystems. In the intensively grazed cattle pasture we observed considerable changes in plant species composition and species cover. Vegetation cover, plant species richness, pasture yield, forage quality and below-ground phytomass declined due to overgrazing. In contrast, the untrampled and unmanured habitat below the fence of the paddock can be regarded as a retreat area for many plant species which do not tolerate heavy trampling and manuring. Thus, in assessing biodiversity, this corridor should be taken into consideration. Within the paddock, we found a permanent transfer of soil nutrients and organic matter by grazing cattle, leading to a high spatial heterogeneity in some soil properties. Consequently, within intensively grazed paddocks differential manure-application rates and variations in grazing intensity are necessary.

Estimation of Soil Erosion by Using Magnetic Method: A Case Study of an Agricultural Field in Southern Moravia (Czech Republic)

NASA Astrophysics Data System (ADS)

Petrovsky, E.; Grison, H.; Kapicka, A.; Dlouha, S.; Kodesova, R.; Jaksik, O.

2013-05-01

In this study we have applied magnetism of soils for estimation of erosion at an agricultural land. The testing site is situated in loess region in Southern Moravia (in Central Europe). The approach is based on well-established method of differentiation of magnetic parameters of the topsoil and the subsoil horizons as a result of in situ formation of strongly magnetic iron oxides. Our founding is established on a simple tillage homogenization model described by Royall (2001) using magnetic susceptibility and its frequency dependence to estimate soil loss caused by the tillage and subsequent erosion. The original dominant Soil Unit in the investigated area is Haplic Chernozem, which is due to intensive erosion progressively transformed into different Soil Units. The site is characterized by a flat upper part while the middle part, formed by a substantive side valley, is steeper (up to 15°). The side valley represents a major line of concentrated runoff emptying into a colluvial fan. Field measurements of the topsoil volume magnetic susceptibility were carried out by the Bartington MS2D probe. Data are resulting in regular grid of 101 data points, where the bulk soil material was gathered for further laboratory investigations. Moreover, vertical distribution of magnetic susceptibility (deep to 40 cm) was measured on selected transects using the SM400 kappameter. In the laboratory, after drying and sieving of collected soil samples, mass-specific magnetic susceptibility and its frequency-dependent susceptibility was measured. In order to identify magnetic minerals the thermomagnetic analyses were performed using the AGICO KLY-4S Kappabridge with CS-3 furnace. Hysteresis loops were carried out on vibrating magnetometer ADE EV9 to assess the grain-size distribution of ferrimagnetic particles. Hereafter, the isothermal remanent magnetization acqusition followed by D.C. demagnetization were done. All these laboratory magnetic measurements were performed in order to compare differences along soil profiles including A, B horizons and undisturbed soil, which is fundamental for magnetic estimation of soil loss. Regression analysis was used to evaluate correlations between magnetic parameters and some chemical properties of soil. For example, higher values of magnetic susceptibility and organic carbon content were measured at the flat upper part, where the original top horizon remained. On the steep valley side these values were much lower, because the original topsoil was eroded and mixed by tillage with the soil substrate (loess). The result confirm positive correlation (R2=0.89) between values of organic carbon content and volume magnetic susceptibility. This study was supported by NAZV Agency of the Ministry of Agriculture of the Czech Republic through grant NO. QJ1230319. References: Royall, D. (2001). Use of mineral magnetic measurements to investigate soil erosion and sediment delivery in a small agricultural catchment in limestone terrain. Catena, 46, 15-34.

Soil hydrological and soil property changes resulting from termite activity on agricultural fields in Burkina Faso

NASA Astrophysics Data System (ADS)

Mettrop, I.; Cammeraat, L. H.; Verbeeten, E.

2009-04-01

Termites are important ecosystem-engineers in subtropical and tropical regions. The effect of termite activity affecting soil infiltration is well documented in the Sahelian region. Most studies find increased infiltration rates on surfaces that are affected by termite activity in comparison to crusted areas showing non-termite presence. Crusted agricultural fields in the Sanmatenga region in Burkina Faso with clear termite activity were compared to control fields without visual ground dwelling termite activity. Fine scale rainfall simulations were carried out on crusted termite affected and control sites. Furthermore soil moisture change, bulk density, soil organic matter as well as general soil characteristics were studied. The top soils in the study area were strongly crusted (structural crust) after the summer rainfall and harvest of millet. They have a loamy sand texture underlain by a shallow sandy loam Bt horizon. The initial soil moisture conditions were significantly higher on the termite plots when compared to control sites. It was found that the amount of runoff produced on the termite plots was significantly higher, and also the volumetric soil moisture content after the experiments was significantly lower if compared to the control plots. Bulk density showed no difference whereas soil organic matter was significantly higher under termite affected areas, in comparison to the control plots. Lab tests showed no significant difference in hydrophobic behavior of the topsoil and crust material. Micro and macro-structural properties of the topsoil did not differ significantly between the termite sites and the control sites. The texture of the top 5 cm of the soil was also found to be not significantly different. The infiltration results are contradictory to the general literature, which reports increased infiltration rates after prolonged termite activity although mostly under different initial conditions. The number of nest entrances was clearly higher in the termite areas, but apparently did not significantly affect infiltration. The increased soil organic matter contents in the termite affected areas however, are as expected from literature, but did not improve soil aggregation which would be expected given the importance of organic matter in soil aggregation in this type of soils. One of the explanations for the reduced infiltration rates might be that termites bring clay from the finer textured subsoil to the surface to build casts over the organic material on the surface (mainly millet stems). It is speculated that the excavated clay material could be involved in crust formation, only present is in the upper 0.5 cm of the soil crust, which is enough to block pores in the crust surface, hampering infiltration. The topsoil aggregates are slaking under the summer rainfall and the increase in fine textured material, excavated by the termites, could be incorporated into the crust and reduce infiltration. Furthermore this specific effect might also be related to the type of termite involved, as impacts from ecosystem engineers on their environment is highly dependent on the specific species involved.

Geochemical signature and phytoremediation of urban soil: a case in Barcelona city

NASA Astrophysics Data System (ADS)

Rodríguez-Bocanegra, Javier; Roca, Núria; Febrero, Anna; Bort, Jordi

2016-04-01

The cleanup of contaminated places with heavy metals is necessary, but environmental remediation strategies are often expensive and energy consuming. Thus, it is important to develop low-cost and environmentally friendly strategies. Phytoremediation-based technologies could provide a long-lasting solution. The study area is located in Sants, a neighbourhood in Barcelona city (Catalonia, Spain). This place was an industrial area in the last century, which was occupied by a metal smelting industry. Nowadays, the neighbours want to cultivate vegetables in this location, but the history of this area suggests that the soil is polluted by elevated concentrations of heavy metals. The aim of this work was to determine heavy metal concentration in: a) soil, to know the degree of the soil pollution; b) roots and leaves of two plant species, Brassica juncea as an accumulator plant and Solanum lycopersicum as a crop plant, to know the capacity of each species to accumulate metals, and c) drainage water, to evaluate the heavy metal mobility. The main pollutants are Cu, Pb and Zn with topsoil total concentrations about 1355, 2230 and 6239 mg•kg-1, respectively. The established background upper limits in this area in mg•kg-1 were: Cu 145, Pb 91 and Zn 326. The same soil elements for available fractions, extracted with DTPA, were slightly elevated (9.6, 5.8 and 6.7 % of total concentration). The environmental pollution implies great extractability, suggesting the plants in these soils have facility with potentially toxic elements absorption. Instead, the concentrations in subsoil are lower than in topsoil. The concentrations of Cu, Pb and Zn in the plants' leaves are greater in B. juncea 170 ± 52.7, 137 ± 46.3 and 2365 ± 860.4 mg•kg-1, than in S. lycopersicum 102.5 ± 7.1, 22.5 ± 1.3 and 1002 ± 85.2 mg•kg-1 respectively. Furthermore, they are also greater in roots than in leaves. All of them are lower than the threshold to be considered like a hyperaccumulator species. However, Pb concentrations in a crop plant exceeded the 0.10 mg•kg-1 limit established for vegetables devoted for food in the European legislation. Part of these heavy metals were transferred to the drainage water. The range of topsoil with B. juncea drainage water values in μg•L-1 is as follows: Cu 115-162, Pb 23.0-32.0 and Zn 613.8-759.7. Unusual elevated concentrations of Pb (over 10 μg•L-1) were detected in drainage water. These values exceeded the acceptable toxic concentrations in waters, according to the Spanish legislation. Furthermore, the values for subsoil drainage water in μg•L-1 were also elevated (Cu 293-298, Pb 15.6-4.84 and Zn 189.5-120.0).

Assessing the origin of unusual organic formations in lava caves from Canary Islands (Spain)

NASA Astrophysics Data System (ADS)

Miller, Ana Z.; de la Rosa, Jose M.; Garcia-Sanchez, Angela M.; Pereira, Manuel F. C.; Jurado, Valme; Fernández, Octavio; Knicker, Heike; Saiz-Jimenez, Cesareo

2016-04-01

Lava tubes, like other caves, contain a variety of speleothems formed in the initial stage of a lava tube formation or due to leaching and subsequent precipitation of secondary minerals. Primary and secondary mineral formations in lava caves are mainly composed of silicate minerals, although secondary minerals common in limestone caves have been also reported in this type of caves. In addition, unusual colored deposits have been found on the walls and ceilings of lava tubes, some of them of unknown origin and composition. A brown to black-colored mud-like deposits was observed in "Llano de los Caños" Cave, La Palma Island, Canary Islands, Spain. These black deposits coat the wall and ceiling of the lava tube where sub-horizontal fractures occur. FESEM-EDS, X-ray micro-computed tomography and mineralogical analyses were conducted for morphological, 3D microstructural and compositional characterization of these unusual speleothem samples. These techniques revealed that they are mainly composed of amorphous materials, suggesting an organic carbon composition. Hence, analytical pyrolysis (Py-GC/MS), solid-state 13C Nuclear Magnetic Resonance (NMR) and stable isotope analysis were applied to assess the nature and origin of the black deposits. The combination of these analytical tools permits the identification of specific biomarkers (di- and triterpenoids) for tracing the potential sources of the organic compounds in the speleothems. For comparison purposes, samples from the topsoil and overlaying vegetation were also analyzed. Chromatograms resulting from the Py-GC/MS showed an abundance of polysaccharides, lipids and terpenoids typically derived from the vegetation of the area (Erica arborea). In addition, levoglucosan, polycyclic aromatic hydrocarbons and N-containing heterocyclic compounds were detected. They probably derived from the leaching of charred vegetation resulting from a wildfire occurred in the area in 2012. The lack of the typical pattern of odd-over-even in the series of n-alkanes observed for the topsoil and black deposits has been recognized as an indication of fire. The 13C NMR spectrum of the black deposits showed a mixture of alkyl and O-alkyl compounds, carboxylic compounds and polysaccharides. Stable isotope analysis of δ 13C performed on the cave black deposits, topsoil and vegetation confirmed that the source of the organic fraction of the sample is a combination of partially charred vegetation (mainly Erica) and organic compounds from the andic soil over the cave. Therefore, these black deposits are the result of an input of plant organic matter and charred vegetation into the cave from rock fractures, which may constitute an important source of energy for cave organisms. Acknowledgments: AZM and JMR acknowledge the support from the Marie Curie Fellowships within the 7th European Community Framework Programme (Grants PIEF-GA-2012-328689-DECAVE and PCIG12-GA-2012-333784-Biocharisma respectively). The authors acknowledge the Spanish Ministry of Economy and Competitiveness (project CGL2013-41674-P) and FEDER funds for financial support.

Biodiversity effects on the water balance of an experimental grassland

NASA Astrophysics Data System (ADS)

Leimer, Sophia; Kreutziger, Yvonne; Rosenkranz, Stephan; Beßler, Holger; Engels, Christof; Oelmann, Yvonne; Weisser, Wolfgang W.; Wirth, Christian; Wilcke, Wolfgang

2013-04-01

Plant species richness increases aboveground biomass production in biodiversity experiments. Biomass production depends on and feeds back to the water balance, but it remains unclear how plant species richness influences soil water contents and water fluxes (actual evapotranspiration (ETa), downward flux (DF), and upward flux (UF)). Our objective was to determine the effects of plant species and functional richness and functional identity on soil water contents and water fluxes for two soil depths (0-0.3 and 0.3.-0.7 m). To achieve this, we used a water balance model in connection with Bayesian hierarchical modeling. We monitored soil water contents on 86 plots of a grassland plant diversity experiment in Jena, Germany between July 2002 and January 2006. In the field experiment, plant species richness (0, 1, 2, 4, 8, 16, 60) and functional group composition (0-4 functional groups: legumes, grasses, non-leguminous tall herbs, non-leguminous small herbs) were manipulated in a factorial design. Climate data (air temperature, precipitation, wind velocity, relative humidity, global radiation, soil moisture) was measured at a central climate station between July 2002 and December 2007. Root biomass data from July 2006 was available per plot. Missing water contents per plot and depth were estimated in weekly resolution for the years 2003-2007 with a Bayesian hierarchical model using measured water contents per plot and centrally measured soil moisture. To obtain ETa, DF, and UF of the two different soil depths, we modified a soil water balance model which had been developed for our study site. The model is based on changes in soil water content between subsequent observation dates and modeled potential evapotranspiration which was partitioned between soil layers according to percentage of root biomass. The presence of specific functional groups significantly changed water contents and fluxes with partly opposing effects in the two soil depths. Presence of grasses decreased water contents in both depths, DF in topsoil, and ETa in subsoil, but increased ETa in topsoil. As grasses produce less shade than other plant functional groups because of their leaf morphology, higher ETa in topsoil could be explained by higher soil evaporation. Moreover, grasses have an extensive, shallow rooting system which facilitates exhaustive water use from the upper soil layer and therefore probably decreases water contents and DF. Species richness did not significantly affect water contents and fluxes in both soil layers except that the relation between species richness and water contents in subsoil changed over time. This can be explained by two equivalent but opposite effects. Transpiration increases with biomass which is positively correlated with species richness. By contrast, soil evaporation decreases with species richness because the greater vegetation cover in species-rich communities produces more shade. We conclude that the contrasting effects of plant species richness on transpiration and evaporation counterbalance each other and that functional traits of specific plant functional groups mediate the biologically-induced changes in the water balance.

Hydro-climatic control of stream dissolved organic carbon in headwater catchment

NASA Astrophysics Data System (ADS)

Humbert, Guillaume; Jaffrezic, Anne; Fovet, Ophélie; Gruau, Gérard; Durand, Patrick

2014-05-01

Dissolved organic matter (DOM) is a key form of the organic matter linking together the water and the carbon cycles and interconnecting the biosphere (terrestrial and marine) and the soil. At the landscape scale, land use and hydrology are the main factors controlling the amount of DOM transferred from soils to the stream. In an intensively cultivated catchment, a recent work using isotopic composition of DOM as a marker has identified two different sources of DOM. The uppermost soil horizons of the riparian wetland appear as a quasi-infinite source while the topsoil of the hillslope forms a limited one mobilized by water-table rise and exported to the stream across the upland-riparian wetland-stream continuum. In addition to the exportation of DOM via water fluxes, climatic factors like temperature and precipitation regulate the DOM production by influencing microbial activity and soil organic matter degradation. The small headwater catchment (5 km²) of Kervidy-Naizin located in Brittany is part of the Environment Research Observatory (ORE) AgrHys. Weather and the hydro-chemistry of the stream, and the groundwater levels are daily recorded since 1993, 2000 and 2001 respectively. Over 13 contrasted hydrological years, the annual flow weighted mean concentration of dissolved organic carbon (DOC) is 5.6 mg.L-1 (sd = 0.7) for annual precipitation varying from 488mm to 1327mm and annual mean temperatures of 11°C (sd = 0.6). Based on this considerable dataset and this annual variability, we tried to understand how the hydro-climatic conditions determinate the stream DOC concentrations along the year. From the fluctuations of water table depth, each hydrologic year has been divided into three main period: i) progressive rewetting of the riparian wetland soils, ii) rising and holding high of the water table in the hillslope, iii) drawdown of the water-table, with less and less topsoil connected to the stream. Within each period base flow and storm flow data were first pooled then treated separately and the influence of preceding periods was tested. This hydrological division of time allowed us to identify climate effect on the topsoil DOM stores of the wetland and hillslope separately. Meteorological and hydro-pedological variables, like soil temperatures or duration of the water saturation in the organo-mineral horizons have been used to interpret the DOC concentrations and fluxes at the outlet within each period. The three hydrological periods contribute respectively to less than 17%, more than 63%, and less than 26% of the annual DOM exportation with flow weighted mean concentration of DOC of 9.5, 6.1, and 3.8 mg.L-1. Considering several DOM sources with different properties of depletion under climatic control, the main output of the work is to provide a modified conceptual model of the DOC dynamics.

Plant reestablishment after soil disturbance: Effects of soils, treatment, and time

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brandt, C.A.; Alford, K.; McIlveny, G.

The Pacific Northwest Laboratory examined plant growth and establishment on 16 sites where severe land disturbance had taken place. The purpose of the study was to evaluate the relative effectiveness of the different methods in term of their effects on establishment of native and alien plants. Disturbances ranged from 1 to 50 years in age. Revegetation using native plants had been attempted at 14 of the sites; the remainder were abandoned without any further management. Revegetation efforts variously included seeding, fertilizer application, mulching with various organic sources, compost application, application of Warden silt loam topsoil over sand and gravel soils,more » and moderate irrigation.« less

Retrospective 70 y-spatial analysis of repeated vine mortality patterns using ancient aerial time series, Pléiades images and multi-source spatial and field data

NASA Astrophysics Data System (ADS)

Vaudour, E.; Leclercq, L.; Gilliot, J. M.; Chaignon, B.

2017-06-01

For any wine estate, there is a need to demarcate homogeneous within-vineyard zones ('terroirs') so as to manage grape production, which depends on vine biological condition. Until now, the studies performing digital zoning of terroirs have relied on recent spatial data and scant attention has been paid to ancient geoinformation likely to retrace past biological condition of vines and especially occurrence of vine mortality. Is vine mortality characterized by recurrent and specific patterns and if so, are these patterns related to terroir units and/or past landuse? This study aimed at performing a historical and spatial tracing of vine mortality patterns using a long time-series of aerial survey images (1947-2010), in combination with recent data: soil apparent electrical conductivity EM38 measurements, very high resolution Pléiades satellite images, and a detailed field survey. Within a 6 ha-estate in the Southern Rhone Valley, landuse and planting history were retraced and the map of missing vines frequency was constructed from the whole time series including a 2015-Pléiades panchromatic band. Within-field terroir units were obtained from a support vector machine classifier computed on the spectral bands and NDVI of Pléiades images, EM38 data and morphometric data. Repeated spatial patterns of missing vines were highlighted throughout several plantings, uprootings, and vine replacements, and appeared to match some within-field terroir units, being explained by their specific soil characteristics, vine/soil management choices and the past landuse of the 1940s. Missing vines frequency was spatially correlated with topsoil CaCO3 content, and negatively correlated with topsoil iron, clay, total N, organic C contents and NDVI. A retrospective spatio-temporal assessment of terroir therefore brings a renewed focus on some key parameters for maintaining a sustainable grape production.

Building Interactive Visualizations for Geochronological Data

NASA Astrophysics Data System (ADS)

Zeringue, J.; Bowring, J. F.; McLean, N. M.; Pastor, F.

2014-12-01

Since the early 1990s, Ken Ludwig's Isoplot software has been the tool of choice for visualization and analysis of isotopic data used for geochronology. The software is an add-in to Microsoft Excel that allows users to generate visual representations of data. However, recent changes to Excel have made Isoplot more difficult to use and maintain, and the software is no longer supported. In the last several years, the Cyber Infrastructure Research and Development Lab for the Earth Sciences (CIRDLES), at the College of Charleston, has worked collaboratively with geochronologists to develop U-Pb_Redux, a software product that provides some of Isoplot's functionality for U-Pb geochronology. However, the community needs a full and complete Isoplot replacement that is open source, platform independent, and not dependent on proprietary software. This temporary lapse in tooling also presents a tremendous opportunity for scientific computing in the earth sciences. When Isoplot was written for Excel, it gained much of the platform's flexibility and power but also was burdened with its limitations. For example, Isoplot could not be used outside of Excel, could not be cross-platform (so long as Excel wasn't), could not be embedded in other applications, and only static images could be produced. Nonetheless this software was and still is a powerful tool that has served the community for more than two decades and the trade-offs were more than acceptable. In 2014, we seek to gain flexibility not available with Excel. We propose that the next generation of charting software be reusable, platform-agnostic, and interactive. This new software should allow scientists to easily explore—not just passively view—their data. Beginning in the fall of 2013, researchers at CIRDLES began planning for and prototyping a 21st-century replacement for Isoplot, which we call Topsoil, an anagram of Isoplot. This work is being conducted in the public domain at https://github.com/CIRDLES/topsoil. We welcome and encourage community participation and contributions.

The importance of ingested soils in supplying fluorine and lead to sheep grazing contaminated pastures in the Peak District mining area of Derbyshire, UK.

PubMed

Abrahams, Peter W; Blackwell, Nia L

2013-12-01

For sheep grazing pastures in areas of mineralisation and former metalliferous mining activity, an excessive intake of potentially harmful elements (PHEs) such as fluorine (F) and lead (Pb) can result in clinical and subclinical toxicity. The prime aim of our work was to calculate the intakes of both of these PHEs by sheep grazing pastures in the mineralised/mined Peak District area of Derbyshire. The bi-monthly sampling of topsoils (0-15 cm depth) and the faeces of sheep from fields at seven farms was undertaken for a 1-year period. These samples were analysed for titanium that allowed the rates of soil ingestion (and hence also herbage ingestion since we assume that the sheep have an overall diet of 1 kg dry matter (DM)/day) to be determined. Our findings were then combined with previously published soil and soil-free pasture herbage F and Pb concentrations determined from the seven farms to calculate the intakes of both PHEs. The results show seasonal variations of soil ingestion at the seven farms ranging from <0.1 to 20.1 % of the DM intake (median=3 %), with the highest rates of ingestion being associated with the winter-spring (i.e. December-April) period. Our calculations show that at some farms, sheep can be exposed to dietary concentrations in excess of recommended guidelines potentially throughout the whole year, though livestock movement to less-contaminated pastures would lessen any toxic impact. Because the soil concentrations are greater than those associated with soil-free pasture herbage, ingested soils are the main dietary source of Pb and (especially) F to sheep. However, subjecting freshly sampled topsoils to sequential extraction procedures undertaken in the laboratory indicates that the majority of Pb and (especially) F may not be readily soluble in the ovine digestion system, so reducing the quantities of both PHEs available for absorption.

Assessment of vegetation establishment on tailings dam at an iron ore mining site of suburban Beijing, China, 7 years after reclamation with contrasting site treatment methods.

PubMed

Yan, Demin; Zhao, Fangying; Sun, Osbert Jianxin

2013-09-01

Strip-mining operations greatly disturb soil, vegetation and landscape elements, causing many ecological and environmental problems. Establishment of vegetation is a critical step in achieving the goal of ecosystem restoration in mining areas. At the Shouyun Iron Ore Mine in suburban Beijing, China, we investigated selective vegetation and soil traits on a tailings dam 7 years after site treatments with three contrasting approaches: (1) soil covering (designated as SC), (2) application of a straw mat, known as "vegetation carpet", which contains prescribed plant seed mix and water retaining agent (designated as VC), on top of sand piles, and (3) combination of soil covering and application of vegetation carpet (designated as SC+VC). We found that after 7 years of reclamation, the SC+VC site had twice the number of plant species and greater biomass than the SC and VC sites, and that the VC site had a comparable plant abundance with the SC+VC site but much less biodiversity and plant coverage. The VC site did not differ with the SC site in the vegetation traits, albeit low soil fertility. It is suggested that application of vegetation carpet can be an alternative to introduction of topsoil for treatment of tailings dam with fine-structured substrate of ore sands. However, combination of topsoil treatment and application of vegetation carpet greatly increases vegetation coverage and plant biodiversity, and is therefore a much better approach for assisting vegetation establishment on the tailings dam of strip-mining operations. While application of vegetation carpet helps to stabilize the loose surface of fine-structured mine wastes and to introduce seed bank, introduction of fertile soil is necessary for supplying nutrients to plant growth in the efforts of ecosystem restoration of mining areas.

[Estimating heavy metal concentrations in topsoil from vegetation reflectance spectra of Hyperion images: A case study of Yushu County, Qinghai, China.

PubMed

Yang, Ling Yu; Gao, Xiao Hong; Zhang, Wei; Shi, Fei Fei; He, Lin Hua; Jia, Wei

2016-06-01

In this study, we explored the feasibility of estimating the soil heavy metal concentrations using the hyperspectral satellite image. The concentration of As, Pb, Zn and Cd elements in 48 topsoil samples collected from the field in Yushu County of the Sanjiangyuan regions was measured in the laboratory. We then extracted 176 vegetation spectral reflectance bands of 48 soil samples as well as five vegetation indices from two Hyperion images. Following that, the partial least squares regression (PLSR) method was employed to estimate the soil heavy metal concentrations using the above two independent sets of Hyperion-derived variables, separately constructed the estimation model between the 176 vegetation spectral reflectance bands and the soil heavy metal concentrations (called the vegetation spectral reflectance-based estimation model), and between the five vegetation indices being used as the independent variable and the soil heavy metal concentrations (called synthetic vegetation index-based estimation model). Using RPD (the ratio of standard deviation from the 4 heavy metals measured values of the validation samples to RMSE) as the validation criteria, the RPDs of As and Pb concentrations from the two models were both less than 1.4, which suggested that both models were incapable of roughly estimating As and Pb concentrations; whereas the RPDs of Zn and Cd were 1.53, 1.46 and 1.46, 1.42, respectively, which implied that both models had the ability for rough estimation of Zn and Cd concentrations. Based on those results, the vegetation spectral-based estimation model was selected to obtain the spatial distribution map of Zn concentration in combination with the Hyperion image. The estimated Zn map showed that the zones with high Zn concentrations were distributed near the provincial road 308, national road 214 and towns, which could be influenced by human activities. Our study proved that the spectral reflectance of Hyperion image was useful in estimating the soil concentrations of Zn and Cd.

Impact of rainfall patterns and frequency on the export of pesticides and heavy-metals from agricultural soils.

PubMed

Meite, Fatima; Alvarez-Zaldívar, Pablo; Crochet, Alexandre; Wiegert, Charline; Payraudeau, Sylvain; Imfeld, Gwenaël

2018-03-01

The combined influence of soil characteristics, pollutant aging and rainfall patterns on the export of pollutants from topsoils is poorly understood. We used laboratory experiments and parsimonious modeling to evaluate the impact of rainfall characteristics on the ponding and the leaching of a pollutant mixture from topsoils. The mixture included the fungicide metalaxyl, the herbicide S-metolachlor, as well as copper (Cu) and zinc (Zn). Four rainfall patterns, which differed in their durations and intensities, were applied twice successively with a 7days interval on each soil type. To evaluate the influence of soil type and aging, experiments included crop and vineyard soils and two stages of pollutant aging (0 and 10days). The global export of pollutants was significantly controlled by the rainfall duration and frequency (P<0.01). During the first rainfall event, the longest and most intense rainfall pattern yielded the largest export of metalaxyl (44.5±21.5% of the initial mass spiked in the soils), S-metolachlor (8.1±3.1%) and Cu (3.1±0.3%). Soil compaction caused by the first rainfall reduced in the second rainfall the leaching of remaining metalaxyl, S-metolachlor, Cu and Zn by 2.4-, 2.9-, 30- and 50-fold, respectively. In contrast, soil characteristics and aging had less influence on pollutant mass export. The soil type significantly influenced the leaching of Zn, while short-term aging impacted Cu leaching. Our results suggest that rainfall characteristics predominantly control export patterns of metalaxyl and S-metolachlor, in particular when the aging period is short. We anticipate our study to be a starting point for more systematic evaluation of the dissolved pollutant ponding/leaching partitioning and the export of pollutant mixtures from different soil types in relation to rainfall patterns. Copyright © 2017 Elsevier B.V. All rights reserved.

Spatial prediction of soil texture in region Centre (France) from summary data

NASA Astrophysics Data System (ADS)

Dobarco, Mercedes Roman; Saby, Nicolas; Paroissien, Jean-Baptiste; Orton, Tom G.

2015-04-01

Soil texture is a key controlling factor of important soil functions like water and nutrient holding capacity, retention of pollutants, drainage, soil biodiversity, and C cycling. High resolution soil texture maps enhance our understanding of the spatial distribution of soil properties and provide valuable information for decision making and crop management, environmental protection, and hydrological planning. We predicted the soil texture of agricultural topsoils in the Region Centre (France) combining regression and area-to-point kriging. Soil texture data was collected from the French soil-test database (BDAT), which is populated with soil analysis performed by farmers' demand. To protect the anonymity of the farms the data was treated by commune. In a first step, summary statistics of environmental covariates by commune were used to develop prediction models with Cubist, boosted regression trees, and random forests. In a second step the residuals of each individual observation were summarized by commune and kriged following the method developed by Orton et al. (2012). This approach allowed to include non-linear relationships among covariates and soil texture while accounting for the uncertainty on areal means in the area-to-point kriging step. Independent validation of the models was done using data from the systematic soil monitoring network of French soils. Future work will compare the performance of these models with a non-stationary variance geostatistical model using the most important covariates and summary statistics of texture data. The results will inform on whether the later and statistically more-challenging approach improves significantly texture predictions or whether the more simple area-to-point regression kriging can offer satisfactory results. The application of area-to-point regression kriging at national level using BDAT data has the potential to improve soil texture predictions for agricultural topsoils, especially when combined with existing maps (i.e., model ensemble).

Application of Landfill Leachate Improves Wheat Nutrition and Yield but Has Minor Effects on Soil Properties.

PubMed

Kuwano, Biana H; Nogueira, Marco A; Santos, Cristiane A; Fagotti, Dáfila S L; Santos, Michele B; Lescano, Luís E A M; Andrade, Diva S; Barbosa, Graziela M C; Tavares-Filho, João

2017-01-01

Landfill leachates, which are potential pollutants, may also carry significant amounts of nutrients that can be recycled by plants. We assessed the nutritional status and yield of wheat ( L.) and properties of a Rhodic Kandiudult soil (depths of 0-10, 10-20, 20-40, and 40-60 cm) after 11 applications of landfill leachate over 4 yr. In the last application, wheat received 0, 32.7, 65.4, 98.1, or 130.8 m ha (875 mg L of nitrogen, N) of leachate and a positive control (90 kg ha of N as urea) 15 d after sowing. Urea increased nitrate (>160 mg kg) in the topsoil (down to 40 cm), whereas landfill leachate increased nitrate (>60 mg kg) only at 40 to 60 cm with the highest dose, suggesting leaching. Urea-treated soil had less negative ΔpH, which might have led to greater retention of nitrate in the topsoil. Sodium (0.02-0.26 cmol Na kg), potassium (0.18-0.82 cmol K kg), and electrical conductivity (0.05-0.14 dS m) all increased with leachate dosage. Treatments did not affect resistance to penetration and clay dispersion. Basal respiration increased with leachate dosage, whereas dehydrogenase activity decreased, suggesting effects on soil microbial metabolism. Microbial biomass and soil enzyme activities were not affected by addition of leachate. Nitrogen nutrition (15.1-22.7 g N kg in flag leaves) and grain yield (1381-2378 kg grain ha) increased with leachate dosage so that the highest dose gave results similar to those for urea-treated plants (2563 kg grain ha). Landfill leachate showed strong potential as source of N for wheat but caused none, or transient, effects on soil properties. However, nitrate from leachate was more leachable than nitrate from urea. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Effect of mismanagement at the state of organic matter in soil

NASA Astrophysics Data System (ADS)

Hladký, Jan; Elbl, Jakub; Kynický, Jindřich; Dvořáčková, Helena; Juřička, David; Pecina, Václav; Brtnický, Martin

2017-04-01

Organic matter is an essential part of the soil. It affects the physical, chemical, and biological properties of the soil. It is therefore necessary to maintain organic matter in the soil and its quality as the prevention of soil degradation. Loss of organic matter is in the Czech Republic threatened up to 45% of arable soil. The most important reason for the loss of organic matter in the soil is poor management, especially improper crop rotation, cultivation of erosion-prone crops where erosion takes away valuable topsoil with nutrients and organic matter. The aim of our study was to verify the influence of inappropriate management on selected 5 plots in southern Moravia in the Czech Republic. It is the region with the highest incidence of water erosion in the Czech Republic. Were selected plots with significantly sloping, where corn was grown. Samples were taken in the autumn after the harvest, each of topsoil. The sampling sites were placed in positions on the slope where soil was not damaged by erosion, as well as the place greatest damage and the place where washed soil was accumulated. Soil average humus content was for undamaged position on the slope 1.93% and 0.84 quality, the most heavily damaged part of the slope humus content dropped to 1.35% and its quality at only 0.56. In the case of position of accumulated soils was found the average amount of humus 1.70% and 0.90 quality. Humus content and its quality is statistically significantly influenced by water erosion (α = 0.05). The study showed that bad management, when there is not crop rotation adapted to the given conditions and not subjected to any suitable soil-protecting technologies, there is significant damage to soils, which shows mainly organic matter decline and a decline in its quality. Continuation of our study will verify the possibility of stabilization of soil organic matter and draft appropriate technologies.

Effect of variable soil texture, metal saturation of soil organic matter (SOM) and tree species composition on spatial distribution of SOM in forest soils in Poland.

PubMed

Gruba, Piotr; Socha, Jarosław; Błońska, Ewa; Lasota, Jarosław

2015-07-15

In this study we investigated the effect of fine (ϕ<0.05mm) fraction, i.e., silt+clay (FF) content in soils, site moisture, metal (Al and Fe) of soil organic matter (SOM) and forest species composition on the spatial distribution of carbon (C) pools in forest soils at the landscape scale. We established 275 plots in regular 200×200m grid in a forested area of 14.4km(2). Fieldwork included soil sampling of the organic horizon, mineral topsoil and subsoil down to 40cm deep. We analysed the vertical and horizontal distribution of soil organic carbon (SOC) stocks, as well as the quantity of physically separated fractions including the free light (fLF), occluded light (oLF) and mineral associated fractions (MAF) in the mineral topsoil (A, AE) horizons. Distribution of C in soils was predominantly affected by the variation in the FF content. In soils richer in the FF more SOC was accumulated in mineral horizons and less in the organic horizons. Accumulation of SOC in mineral soil was also positively affected by the degree of saturation of SOM with Al and Fe. The increasing share of beech influenced the distribution of C stock in soil profiles by reducing the depth of O horizon and increasing C stored in mineral soil. The content of FF was positively correlated with the content of C in MAF and fLF fractions. The content of oLF and MAF fractions was also positively influenced by a higher degree of metal saturation, particularly Al. Our results confirmed that Al plays an important role in the stabilization of SOM inside aggregates (CoLF) and as in CMAF fractions. We also found a significant, positive effect of beech on the CfLF and fir on the CoLF content. Copyright © 2015 Elsevier B.V. All rights reserved.

Historic land use and land use changes in Lower Lusatia (Brandenburg, East Germany)

NASA Astrophysics Data System (ADS)

Nicolay, A.; Raab, A.; Raab, T. A.; Rösler, H.; Bönisch, E.

2011-12-01

In the apron of the active lignite open cast mine Jänschwalde (Lower Lusatia, Brandenburg, East Germany) geoscientists from the BTU Cottbus and archaeologists from the Brandenburgisches Landesamt für Denkmalpflege und Archäologisches Landesmuseum jointly investigate the impact of prehistoric and historic land use on the landscape. In the study area evidence of different land use and land use change is abundant. Amongst others, the presumably largest charcoal production area in Germany was found which was used from medieval to modern times. Charcoal burning and related activities certainly had tremendous environmental impacts. Archaeological surveys and excavations offer excellent outcrop situations. Fieldwork started in 2010 and concentrates on an area where aeolian drift and coversands are widespread. We assume that the formation of these aeolian coversands is the result of deforestation for charcoal burning and agricultural land use. To study pedology, geomorphology and landscape development on a landscape scale several up to 150 m long and 2 m depth cross-sections were carried out. Field methods include topographical surveying (by differential GPS) and the description of soils and sediments. Laboratory methods (e.g., soil texture, TOC, contents of pedogenic oxides) are carried out for soil characterization. In addition, for chronological information radiocarbon (14C) and optical stimulated luminescence (OSL) dating as well as dendrochronological age determinations are applied on selected materials. Our preliminary results from several cross-sections show that the landscape was used in different ways. Buried topsoil horizons of the Roman Imperial period (50-315 AD) and the Migration period (375-600 AD) are found. Moreover agricultural soil horizons from the Slavic medieval period (600-1200 AD) are present. The former topsoils are covered by 10-150 cm thick aeolian drift sands which can be differentiated by pedological and sedimentological means into two phases, whereby the later one dates to the main phase of charcoal production in modern times.

The use of crop rotation for mapping soil organic content in farmland

NASA Astrophysics Data System (ADS)

Yang, Lin; Song, Min; Zhu, A.-Xing; Qin, Chengzhi

2017-04-01

Most of the current digital soil mapping uses natural environmental covariates. However, human activities have significantly impacted the development of soil properties since half a century, and therefore become an important factor affecting soil spatial variability. Many researches have done field experiments to show how soil properties are impacted and changed by human activities, however, spatial variation data of human activities as environmental covariates have been rarely used in digital soil mapping. In this paper, we took crop rotation as an example of agricultural activities, and explored its effectiveness in characterizing and mapping the spatial variability of soil. The cultivated area of Xuanzhou city and Langxi County in Anhui Province was chosen as the study area. Three main crop rotations,including double-rice, wheat-rice,and oilseed rape-cotton were observed through field investigation in 2010. The spatial distribution of the three crop rotations in the study area was obtained by multi-phase remote sensing image interpretation using a supervised classification method. One-way analysis of variance (ANOVA) for topsoil organic content in the three crop rotation groups was performed. Factor importance of seven natural environmental covariates, crop rotation, Land use and NDVI were generated by variable importance criterion of Random Forest. Different combinations of environmental covariates were selected according to the importance rankings of environmental covariates for predicting SOC using Random Forest and Soil Landscape Inference Model (SOLIM). A cross validation was generated to evaluated the mapping accuracies. The results showed that there were siginificant differences of topsoil organic content among the three crop rotation groups. The crop rotation is more important than parent material, land use or NDVI according to the importance ranking calculated by Random Forest. In addition, crop rotation improved the mapping accuracy, especially for the flat clutivated area. This study demonstrates the usefulness of human activities in digital soil mapping and thus indicates the necessity for human activity factors in digital soil mapping studies.

Soil architecture relationships with dynamic soil physical processes: a conceptual study using natural, artificial, and 3D-printed soil cores

NASA Astrophysics Data System (ADS)

Lamandé, Mathieu; Schjønning, Per; Dal Ferro, Nicola; Morari, Francesco

2017-04-01

Pore system architecture is a key feature for understanding physical, biological and chemical processes in soils. Development of visualisation technics, especially x-ray CT, during recent years has been useful in describing the complex relationships between soil architecture and soil functions. We believe that combining visualization with physical models is a step further towards a better understanding of these relationships. We conducted a concept study using natural, artificial and 3D-printed soil cores. Eight natural soil cores (100 cm3) were sampled in a cultivated stagnic Luvisol at two depths (topsoil and subsoil), representing contrasting soil pore systems. Cylinders (100 cm3) were produced from plastic or from autoclaved aerated concrete. Holes of diameters 1.5 and 3 mm were drilled in the cylinder direction for the plastic cylinder and for one of the AAC cylinders. All natural and artificial cores were scanned in a micro x-ray CT scanner at a resolution of 35 µm. The reconstructed image of each soil core was printed with 3D multijet printing technology at a resolution of 29 µm. In some reconstructed digital volumes of the natural soil cores, pores of different sizes (equivalent diameter of 35, 70, 100, and 200 µm) were removed before additional 3D printing. Effective air-filled porosity, Darcian air permeability, and oxygen diffusion were measured on all natural, artificial and printed cores. The comparison of the natural and the artificial cores emphasized the difference in pore architecture between topsoil (sponge like) and subsoil (dominated by large vertical macropores). This study showed the high potential of using printed soil cores for understanding soil pore functions. The results confirm the suitability of the Ball model partitioning the pore system into arterial, marginal and remote pores to describe effects of soil structure on gas transport.

Spatial distribution and temporal variability of arsenic in irrigated rice fields in Bangladesh. 2. Paddy soil.

PubMed

Dittmar, Jessica; Voegelin, Andreas; Roberts, Linda C; Hug, Stephan J; Saha, Ganesh C; Ali, M Ashraf; Badruzzaman, A Borhan M; Kretzschmar, Ruben

2007-09-01

Arsenic-rich groundwater from shallow tube wells is widely used for the irrigation of boro rice in Bangladesh and West Bengal. In the long term this may lead to the accumulation of As in paddy soils and potentially have adverse effects on rice yield and quality. In the companion article in this issue, we have shown that As input into paddy fields with irrigation water is laterally heterogeneous. To assess the potential for As accumulation in soil, we investigated the lateral and vertical distribution of As in rice field soils near Sreenagar (Munshiganj, Bangladesh) and its changes over a 1 year cycle of irrigation and monsoon flooding. At the study site, 18 paddy fields are irrigated with water from a shallow tube well containing 397 +/- 7 microg L(-1) As. The analysis of soil samples collected before irrigation in December 2004 showed that soil As concentrations in paddy fields did not depend on the length of the irrigation channel between well and field inlet. Within individual fields, however, soil As contents decreased with increasing distance to the water inlet, leading to highly variable topsoil As contents (11-35 mg kg(-1), 0-10 cm). Soil As contents after irrigation (May 2005) showed that most As input occurred close to the water inlet and that most As was retained in the top few centimeters of soil. After monsoon flooding (December 2005), topsoil As contents were again close to levels measured before irrigation. Thus, As input during irrigation was at least partly counteracted by As mobilization during monsoon flooding. However, the persisting lateral As distribution suggests net arsenic accumulation over the past 15 years. More pronounced As accumulation may occur in regions with several rice crops per year, less intense monsoon flooding, or different irrigation schemes. The high lateral and vertical heterogeneity of soil As contents must be taken into account in future studies related to As accumulation in paddy soils and potential As transfer into rice.

Geochemical baseline distribution of harmful elements in the surface soils of Campania region.

NASA Astrophysics Data System (ADS)

Albanese, Stefano; Lima, Annamaria; Qu, Chengkai; Cicchella, Domenico; Buccianti, Antonella; De Vivo, Benedetto

2015-04-01

Environmental geochemical mapping has assumed an increasing relevance and the separation of values to discriminate between anthropogenic pollution and natural (geogenic) sources has become crucial to address environmental problems affecting the quality of life of human beings. In the last decade, a number of geochemical prospecting projects, mostly focused on surface soils (topsoils), were carried out at different scales (from regional to local) across the whole Campania region (Italy) to characterize the distribution of both harmful elements and persistent organic pollutants (POP) in the environment and to generating a valuable database to serve as reference in developing geomedical studies. During the 2014, a database reporting the distribution of 53 chemical elements in 3536 topsoil samples, collected across the whole region, was completed. The geochemical data, after necessary quality controls, were georeferenced and processed in a geochemistry dedicated GIS software named GEODAS. For each considered element a complete set of maps was generated to depict both the discrete and the spatially continuous (interpolated) distribution of elemental concentrations across the region. The interpolated maps were generated using the Multifractal Inverse Distance eighted (MIDW) algorithm. Subsequently, the S-A method, also implemented in GEODAS, was applied to MIDW maps to eliminate spatially limited anomalies from the original grid and to generate the distribution patterns of geochemical baselines for each element. For a selected group of elements geochemical data were also treated by means of a Compositional Data Analysis (CoDA) aiming at investigating the regionalised structure of the data by considering the joint behaviour of several elements constituting for each sample its whole composition. A regional environmental risk assessment was run on the basis of the regional distribution of heavy metals in soil, land use types and population. The risk assessment produced a ranking of priorities and located areas of regional territory where human health risk is more relevant and follow-up activities are required.

Radioactive and stable cesium isotope distributions and dynamics in Japanese cedar forests.

PubMed

Yoschenko, Vasyl; Takase, Tsugiko; Hinton, Thomas G; Nanba, Kenji; Onda, Yuichi; Konoplev, Alexei; Goto, Azusa; Yokoyama, Aya; Keitoku, Koji

2018-06-01

Dynamics of the Fukushima-derived radiocesium and distribution of the natural stable isotope 133 Cs in Japanese cedar (Cryptomeria japonica D. Don) forest ecosystems were studied during 2014-2016. For the experimental site in Yamakiya, Fukushima Prefecture, we present the redistribution of radiocesium among ecosystem compartments during the entire observation period, while the results obtained at another two experimental site were used to demonstrate similarity of the main trends in the Japanese forest ecosystems. Our observations at the Yamakiya site revealed significant redistribution of radiocesium between the ecosystem compartments during 2014-2016. During this same period radionuclide inventories in the aboveground tree biomass were relatively stable, however, radiocesium in forest litter decreased from 20 ± 11% of the total deposition in 2014 to 4.6 ± 2.7% in 2016. Radiocesium in the soil profile accumulated in the 5-cm topsoil layers. In 2016, more than 80% of the total radionuclide deposition in the ecosystem resided in the 5-cm topsoil layer. The radiocesium distribution between the aboveground biomass compartments at Yamakiya during 2014-2016 was gradually approaching a quasi-equilibrium distribution with stable cesium. Strong correlations of radioactive and stable cesium isotope concentrations in all compartments of the ecosystem have not been reached yet. However, in some compartments the correlation is already strong. An increase of radiocesium concentrations in young foliage in 2016, compared to 2015, and an increase in 2015-2016 of the 137 Cs/ 133 Cs concentration ratio in the biomass compartments with strong correlations indicate an increase in root uptake of radiocesium from the soil profile. Mass balance of the radionuclide inventories, and accounting for radiocesium fluxes in litterfall, throughfall and stemflow, enabled a rough estimate of the annual radiocesium root uptake flux as 2 ± 1% of the total inventory in the ecosystem. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effects of fertilizer on inorganic soil N in East Africa maize systems: vertical distributions and temporal dynamics.

PubMed

Tully, Katherine L; Hickman, Jonathan; McKenna, Madeline; Neill, Christopher; Palm, Cheryl A

2016-09-01

Fertilizer applications are poised to increase across sub-Saharan Africa (SSA), but the fate of added nitrogen (N) is largely unknown. We measured vertical distributions and temporal variations of soil inorganic N following fertilizer application in two maize (Zea mays L.)-growing regions of contrasting soil type. Fertilizer trials were established on a clayey soil in Yala, Kenya, and on a sandy soil in Tumbi, Tanzania, with application rates of 0-200 kg N/ha/yr. Soil profiles were collected (0-400 cm) annually (for three years in Yala and two years in Tumbi) to examine changes in inorganic N pools. Topsoils (0-15 cm) were collected every 3-6 weeks to determine how precipitation and fertilizer management influenced plant-available soil N. Fertilizer management altered soil inorganic N, and there were large differences between sites that were consistent with differences in soil texture. Initial soil N pools were larger in Yala than Tumbi (240 vs. 79 kg/ha). Inorganic N pools did not change in Yala (277 kg/ha), but increased fourfold after cultivation and fertilization in Tumbi (371 kg/ha). Intra-annual variability in NO - 3 -N concentrations (3-33 μg/g) in Tumbi topsoils strongly suggested that the sandier soils were prone to high leaching losses. Information on soil inorganic N pools and movement through soil profiles can h vulnerability of SSA croplands to N losses and determine best fertilizer management practices as N application rates increase. A better understanding of the vertical and temporal patterns of soil N pools improves our ability to predict the potential environmental effects of a dramatic increase in fertilizer application rates that will accompany the intensification of African croplands. © 2016 by the Ecological Society of America.

Nitrogen (N) Deposition Impacts Seedling Growth of Pinus massoniana via N:P Ratio Effects and the Modulation of Adaptive Responses to Low P (Phosphorus)

PubMed Central

Zhang, Yi; Zhou, Zhichun; Yang, Qing

2013-01-01

Background In forest ecosystems with phosphorus (P) deficiency, the impact of atmospheric nitrogen (N) deposition on nutritional traits related to P uptake and P use potentially determines plant growth and vegetation productivity. Methodology/Principal Findings Two N deposition simulations were combined with three soil P conditions (homogeneous P deficiency with evenly low P; heterogeneous P deficiency with low subsoil P and high topsoil P; high P) using four full-sib families of Masson pine (Pinus massoniana). Under homogeneous P deficiency, N had a low effect on growth due to higher N:P ratios, whereas N-sensitive genotypes had lower N:P ratios and greater N sensitivity. The N effect increased under higher P conditions due to increased P concentration and balanced N:P ratios. An N:P threshold of 12.0–15.0 was detected, and growth was increased by N with an N:P ratio ≤ 12.0 and increased by P with an N:P ratio ≥ 15.0. Under homogeneous P deficiency, increased P use efficiency by N deposition improved growth. Under heterogeneous P deficiency, a greater P deficiency under N deposition due to increased N:P ratios induced greater adaptive responses to low P (root acid phosphatase secretion and topsoil root proliferation) and improved P acquisition and growth. Conclusions/Significance N deposition diversely affected seedling growth across different P conditions and genotypes via N:P ratio effects and the modulation of adaptive responses to low P. The positive impact of N on growth was genotype-specific and increased by soil P addition due to balanced N:P ratios. These results indicate the significance of breeding N-sensitive tree genotypes and improving forest soil P status to compensate for increasing N deposition. PMID:24205376

Evaluation of the Applicability of Environmental Magnetic Pollution Screening in Soils of Basaltic Origin: Results from Nashik Thermal Power Station, Maharashtra, India

NASA Astrophysics Data System (ADS)

Blaha, U.; Nathani, B.; Das, P. K.; Kannan, D.

2011-12-01

Magnetic parameters and heavy metal contents of highly magnetic topsoil of the Deccan Trap basalt region were investigated for their potential to be used for environmental magnetic pollution screening. Data of magnetic susceptibility (χ) and soft isothermal remanent magnetization (Soft IRM) of 55 soil samples from N-S and W-E transects reveal a significant input of anthropogenic magnetic particulate matter within a range of 6 km around both the coal fired power plant and its adjacent ash pond. Less developed and thin topsoil layers as well as limited contribution from the fly ash sources in N direction pose difficulties for unambiguous assessment of the magnetic parameters. Heavy metal data, i.e. Pb, Zn and Cu concentrations of the soil grain size of <63 μm reveal similar distribution patterns as obtained from the magnetic parameters of all directions. Fluctuations are observed in magnetic as well as in heavy metal data and are primarily attributed to soil development. Thermo-magnetic measurements identify magnetite of anthropogenic origin in the vicinity of the pollution source based on Verwey-Transition and Hopkinson peak. The quantitative decrease of the anthropogenic ferrimagnetic mineral concentration with distance is proven by Soft IRM. Confirmation of the presence of extremely high and low amounts of ash particles in the magnetically and chemically distinguished zones is provided by scanning electron microscopy (SEM) on quantitatively extracted magnetic particles at 5.5 km and 11.9 km distance. Evaluation of magnetic and chemical data including pollution load indices (PLIS) of Pb, Zn and Cu reveals good relationship of χ with the metal contents. The highest of the PLIS for Pb, Zn and Cu reveals threefold enhancement of concentration with respect to the natural background at 12 km distance and is obtained close to the fly ash sources.

Decline in Topsoil Microbial Quotient, Fungal Abundance and C Utilization Efficiency of Rice Paddies under Heavy Metal Pollution across South China

PubMed Central

Liu, Yongzhuo; Zhou, Tong; Crowley, David; Li, Lianqing; Liu, Dawen; Zheng, Jinwei; Yu, Xinyan; Pan, Genxing; Hussain, Qaiser; Zhang, Xuhui; Zheng, Jufeng

2012-01-01

Agricultural soils have been increasingly subject to heavy metal pollution worldwide. However, the impacts on soil microbial community structure and activity of field soils have been not yet well characterized. Topsoil samples were collected from heavy metal polluted (PS) and their background (BGS) fields of rice paddies in four sites across South China in 2009. Changes with metal pollution relative to the BGS in the size and community structure of soil microorganisms were examined with multiple microbiological assays of biomass carbon (MBC) and nitrogen (MBN) measurement, plate counting of culturable colonies and phospholipids fatty acids (PLFAs) analysis along with denaturing gradient gel electrophoresis (DGGE) profile of 16S rRNA and 18S rRNA gene and real-time PCR assay. In addition, a 7-day lab incubation under constantly 25°C was conducted to further track the changes in metabolic activity. While the decrease under metal pollution in MBC and MBN, as well as in culturable population size, total PLFA contents and DGGE band numbers of bacteria were not significantly and consistently seen, a significant reduction was indeed observed under metal pollution in microbial quotient, in culturable fungal population size and in ratio of fungal to bacterial PLFAs consistently across the sites by an extent ranging from 6% to 74%. Moreover, a consistently significant increase in metabolic quotient was observed by up to 68% under pollution across the sites. These observations supported a shift of microbial community with decline in its abundance, decrease in fungal proportion and thus in C utilization efficiency under pollution in the soils. In addition, ratios of microbial quotient, of fungal to bacterial and qCO2 are proved better indicative of heavy metal impacts on microbial community structure and activity. The potential effects of these changes on C cycling and CO2 production in the polluted rice paddies deserve further field studies. PMID:22701725

Soil magnetic susceptibility mapping as a pollution and provenance tool: an example from southern New Zealand

NASA Astrophysics Data System (ADS)

Martin, A. P.; Ohneiser, C.; Turnbull, R. E.; Strong, D. T.; Demler, S.

2018-02-01

The presence or absence, degree and variation of heavy metal contamination in New Zealand soils is a matter of ongoing debate as it affects soil quality, agriculture and human health. In many instances, however, the soil heavy metal concentration data do not exist to answer these questions and the debate is ongoing. To address this, magnetic susceptibility (a common proxy for heavy metal contamination) values were measured in topsoil (0-30 cm) and subsoil (50-70 cm) at grid sites spaced at 8 km intervals across ca. 20 000 km2 of southern New Zealand. Samples were measured for both mass- and volume-specific magnetic susceptibility, with results being strongly, positively correlated. Three different methods of determining anomalies were applied to the data including the topsoil-subsoil difference method, Tukey boxplot method and geoaccumulation index method, with each method filtering out progressively more anomalies. Additional soil magnetic (hysteresis, isothermal remanence and thermomagnetic) measurements were made on a select subset of samples from anomalous sites. Magnetite is the dominant remanence carrying mineral, and magnetic susceptibility is governed by that minerals concentration in soils, rather than mineral type. All except two anomalous sites have a dominant geogenic source (cf. anthropogenic). By proxy, heavy metal contamination in southern New Zealand soils is minimal, making them relatively pristine. The provenance of the magnetic minerals in the anomalous sites can be traced back to likely sources in outcrops of igneous rocks within the same catchment, terrane or rock type: a distance of <100 km but frequently <1 km. Soil provenance is a key step when mapping element or isotopic distribution, vectoring to mineralization or studying soil for agricultural suitability, water quality or environmental regulation. Measuring soil magnetic susceptibility is a useful, quick and inexpensive tool that usefully supplements soil geochemical data.

Spatial and temporal variations of thaw layer thickness and its controlling factors identified using time-lapse electrical resistivity tomography and hydro-thermal modeling

NASA Astrophysics Data System (ADS)

Tran, Anh Phuong; Dafflon, Baptiste; Bisht, Gautam; Hubbard, Susan S.

2018-06-01

Quantitative understanding of controls on thaw layer thickness (TLT) dynamics in the Arctic peninsula is essential for predictive understanding of permafrost degradation feedbacks to global warming and hydrobiochemical processes. This study jointly interprets electrical resistivity tomography (ERT) measurements and hydro-thermal numerical simulation results to assess spatiotemporal variations of TLT and to determine its controlling factors in Barrow, Alaska. Time-lapse ERT measurements along a 35-m transect were autonomously collected from 2013 to 2015 and inverted to obtain soil electrical resistivity. Based on several probe-based TLT measurements and co-located soil electrical resistivity, we estimated the electrical resistivity thresholds associated with the boundary between the thaw layer and permafrost using a grid search optimization algorithm. Then, we used the obtained thresholds to derive the TLT from all soil electrical resistivity images. The spatiotemporal analysis of the ERT-derived TLT shows that the TLT at high-centered polygons (HCPs) is smaller than that at low-centered polygons (LCPs), and that both thawing and freezing occur earlier at the HCPs compared to the LCPs. In order to provide a physical explanation for dynamics in the thaw layer, we performed 1-D hydro-thermal simulations using the community land model (CLM). Simulation results showed that air temperature and precipitation jointly govern the temporal variations of TLT, while the topsoil organic content (SOC) and polygon morphology are responsible for its spatial variations. When the topsoil SOC and its thickness increase, TLT decreases. Meanwhile, at LCPs, a thicker snow layer and saturated soil contribute to a thicker TLT and extend the time needed for TLT to freeze and thaw. This research highlights the importance of combination of measurements and numerical modeling to improve our understanding spatiotemporal variations and key controls of TLT in cold regions.

Including hydrological self-regulating processes in peatland models: Effects on peatmoss drought projections.

PubMed

Nijp, Jelmer J; Metselaar, Klaas; Limpens, Juul; Teutschbein, Claudia; Peichl, Matthias; Nilsson, Mats B; Berendse, Frank; van der Zee, Sjoerd E A T M

2017-02-15

The water content of the topsoil is one of the key factors controlling biogeochemical processes, greenhouse gas emissions and biosphere - atmosphere interactions in many ecosystems, particularly in northern peatlands. In these wetland ecosystems, the water content of the photosynthetic active peatmoss layer is crucial for ecosystem functioning and carbon sequestration, and is sensitive to future shifts in rainfall and drought characteristics. Current peatland models differ in the degree in which hydrological feedbacks are included, but how this affects peatmoss drought projections is unknown. The aim of this paper was to systematically test whether the level of hydrological detail in models could bias projections of water content and drought stress for peatmoss in northern peatlands using downscaled projections for rainfall and potential evapotranspiration in the current (1991-2020) and future climate (2061-2090). We considered four model variants that either include or exclude moss (rain)water storage and peat volume change, as these are two central processes in the hydrological self-regulation of peatmoss carpets. Model performance was validated using field data of a peatland in northern Sweden. Including moss water storage as well as peat volume change resulted in a significant improvement of model performance, despite the extra parameters added. The best performance was achieved if both processes were included. Including moss water storage and peat volume change consistently reduced projected peatmoss drought frequency with >50%, relative to the model excluding both processes. Projected peatmoss drought frequency in the growing season was 17% smaller under future climate than current climate, but was unaffected by including the hydrological self-regulating processes. Our results suggest that ignoring these two fine-scale processes important in hydrological self-regulation of northern peatlands will have large consequences for projected climate change impact on ecosystem processes related to topsoil water content, such as greenhouse gas emissions. Copyright © 2016 Elsevier B.V. All rights reserved.

Soil biochemical properties in brown and gray mine soils with and without hydroseeding

NASA Astrophysics Data System (ADS)

Thomas, C.; Sexstone, A.; Skousen, J.

2015-09-01

Surface coal mining in the eastern USA disturbs hundreds of hectares of land every year and removes valuable and ecologically diverse eastern deciduous forests. Reclamation involves restoring the landscape to approximate original contour, replacing the topsoil, and revegetating the site with trees and herbaceous species to a designated post-mining land use. Re-establishing an ecosystem of ecological and economic value as well as restoring soil quality on disturbed sites are the goals of land reclamation, and microbial properties of mine soils can be indicators of restoration success. Reforestation plots were constructed in 2007 using weathered brown sandstone or unweathered gray sandstone as topsoil substitutes to evaluate tree growth and soil properties at Arch Coal's Birch River mine in West Virginia, USA. All plots were planted with 12 hardwood tree species and subplots were hydroseeded with a herbaceous seed mix and fertilizer. After 6 years, the average tree volume index was nearly 10 times greater for trees grown in brown (3853 cm3) compared to gray mine soils (407 cm3). Average pH of brown mine soils increased from 4.7 to 5.0, while gray mine soils declined from 7.9 to 7.0. Hydroseeding doubled tree volume index and ground cover on both mine soils. Hydroseeding doubled microbial biomass carbon (MBC) on brown mine soils (8.7 vs. 17.5 mg kg-1), but showed no effect on gray mine soils (13.3 vs. 12.8 mg kg-1). Hydroseeding also increased the ratio of MBC to soil organic C in both soils and more than tripled the ratio for potentially mineralizable nitrogen (PMN) to total N. Brown mine soils were a better growth medium than gray mine soils and hydroseeding was an important component of reclamation due to improved biochemical properties and microbial activity in mine soils.

Gamma-spectrometric measurement of radioactivity in agricultural soils of the Lombardia region, northern Italy.

PubMed

Guidotti, Laura; Carini, Franca; Rossi, Riccardo; Gatti, Marina; Cenci, Roberto M; Beone, Gian Maria

2015-04-01

This work is part of a wider monitoring project of the agricultural soils in Lombardia, which aims to build a database of topsoil properties and the potentially toxic elements, organic pollutants and gamma emitting radionuclides that the topsoils contain. A total of 156 agricultural soils were sampled according to the LUCAS (Land Use/Cover Area frame statistical Survey) standard procedure. The aim was to provide a baseline to document the conditions present at the time of sampling. The results of the project concerning soil radioactivity are presented here. The aim was to assess the content of (238)U, (232)Th, (137)Cs and (40)K by measuring soil samples by gamma spectrometry. (238)U, (232)Th and (40)K activities range 24-231, 20-70, and 242-1434 Bq kg(-1) respectively. The geographic distribution of (238)U reflects the geophysical framework of the Lombardia region: the soils with high content of uranium are distributed for the most part in the South Alpine belt, where the presence of magmatic rocks is widespread. These soils show an higher activity of (238)U than of (232)Th. The (238)U activities become lower than (232)Th when soils are located in the plain, originating from basic sedimentary rocks. (137)Cs activity ranges 0.4-86.8 kBq m(-2). The lowest activity of (137)Cs is in the plain, whereas the highest is in the North on soils kept as lawn or pasture. The (137)Cs activity of some samples suggests the presence of accumulation processes that lead to (137)Cs enriched soils. This is the first survey of gamma emitting radionuclides in Lombardia that is based on the LUCAS standard sampling. The results from this monitoring campaign are important for the human radiation exposure and provide the zero point, which will be useful for assessing future effects due to external factors such as human activities. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Soils, sediments and geoarchaeology in the vicinity of Caričin Grad (Iustiniana Prima), southern Serbia

NASA Astrophysics Data System (ADS)

Dotterweich, Markus; Köstelbauer, Felix; Schreg, Rainer

2017-04-01

Excavations at the early Byzantine hillfort-settlement Caričin Grad hint at a relatively short time of active settlement of only 90 years. The cause for abandonment is still unknown, though it is widely assumed that ecological and environmental factors played a pivotal role. This study aims to evaluate, if soils and sediments in the vicinity of the site can be used to gather information about the spatial and temporal impact of land use and whether that constituted to a higher rate of soil erosions and thus a possible decline of sustainability during the time of active occupation. A field campaign in 2016 documented the sediments of 15 exposures along riverbanks and erosional gullies as well as 15 core drillings. Samples for dating via radiocarbon and optically-stimulated luminescence (OSL) were also recovered. The field campaign was further supported by a DEM of the research area, archaeological reports, as well as geological, pedological and topographic maps. The heterogeneous stratigraphy of most of the documented sediments strongly reflects the clayey and loamy nature of the catchment areas. Inclusions of charcoal and fractured bricks can be found under two meters of overlaying colluvial and alluvial sediments. Floodplain sediments, especially those near a now bursted dam built in the Byzantine era, show inclusions of bigger stone blocks, hinting at several flashflood events, which occurred during historic times. Most of the topsoil in the catchment area, especially south-west of the site, is already strongly eroded, leaving only Ah-C sequences of Leptosols. The gathered data thus suggest that accelerated soil erosion during the time of occupation was very likely, probably caused by local brick production and deforestation. Exposed topsoil with a relative high amount of clay mineral further contributed to a marginal discharge to groundwater during rainfall, resulting in a stronger runoff and incision of gullies in the present-day landscape.

Distribution of metals in various particle-size fractions in topsoils of a small dry valley system (European Russia, forest zone)

NASA Astrophysics Data System (ADS)

Samonova, Olga; Aseyeva, Elena

2017-04-01

A detailed study of heavy metals distribution in various soil grain-size fractions helps to increase the knowledge about the complex nature of metals' occurrence and their distribution pathways in the environment. On the basis of particle size fractionation of topsoil horizons we examined the specific behavior of heavy metals in a small erosional landform located in the humid temperate zone of the Russian Plain. The object of the study is a 400 m small U-shaped dry valley (balka in Russian) with a catchment area of 32.8 ha located in the central part of the Protva river basin, 100 km southwest of Moscow. The uppermost parts of the landform are incised in Late Pleistocene loessial loams, which cover significant portions of interfluve area in the region, while the middle and the lower parts cut through Middle Pleistocene glacial sediments. A total of 50 samples were collected from topsoil horizons of different landform geomorphic units along three cross-sections as well as along the bottom of the landform and its detrital fan. Samples were analyzed for Mn, Cu, Ni, Co, Cr, Zn, Pb, Ti, Zr, and Fe content. Eleven samples were chosen for physical fractionation into 5 grain-size fractions (1-0.25 mm, 0.25-0.05 mm, 0.05-0.01 mm, 0.01-0.001 mm and <0.001 mm) and further analysis for fractionized metal contents. Across the grain-size fractions the maximum Zr content was observed in the coarse silt fraction and Ti - in the medium and fine silt fraction, while other metals, such as Fe, Mn, Co, Ni, Cr, Pb, and Zn revealed their highest concentrations in the clay fraction. For Fe, Mn, Co and Ni a second concentration peak was observed in the coarse and medium sand fraction. Due to probably eolian genesis and (or) transformation during weathering, the coarse silt fraction in comparison to other fractions showed a depletion of the majority of metals while the minimum concentrations of Ti, Zr and Cr were limited to the coarse and medium sand. Statistical analysis showed that the variation of metal contents depends on particle sizes: the Cv coefficients calculated for Cu, Ni, Co, Fe, Mn, Ti and Zr reach their maximum in the 1-0.25 mm fraction (for Cu and Ni exceeding 75%, for Ti, Zr being around 40%). For Zn, Cr and Pb the maximum variation (50-60%) was found in the 0.25-0.05 mm fraction. In contrast, the two studied silt fractions and also the clay showed very low variations of all metal contents (except for Mn) characteristically in the range between 6% (Cr) and 23.5% (Zn). Unlike the finer fractions, which displayed very poor geochemical differentiation across the landform's geomorphic units, the coarser (sand) fractions showed distinct spatial patterns in the elements' distribution, possibly related to migration processes, the depletion of metals in the landforms' slopes and their prevalent enrichment in the bottom unit is observed.

Linking spatial patterns of soil redistribution traced with 137Cs and soil nutrients in a Mediterranean mountain agroecosystem (NE Spain)

NASA Astrophysics Data System (ADS)

Quijano, Laura; Gaspar, Leticia; Navas, Ana

2016-04-01

Mediterranean mountain agroecosystems are prone to soil loss mainly due to the accelerated erosion as a consequence of human induced changes from agriculture and grazing practices over the last centuries and the climatic conditions (i.e. irregular and scarce precipitations and drought periods). Soil erosion leads to soil degradation inducing the loss of soil functions. The progressive decline of soil functions thereof soil quality is associated to a decrease of soil productivity and can threat the sustainability of cultivated soils. The use of fallout 137Cs as a soil movement tracer provides useful data to identify areas where loss and gain of 137Cs occurs and that of soil. This study aims to address soil movement and soil nutrient dynamics closely related to the status of soil degradation. A rain-fed cereal field (1.6 ha) representative of Mediterranean mountain agricultural landscapes (42°25'41''N 1°13'8''W) was selected to examine the effects of soil redistribution processes on the spatial variability of soil organic carbon (SOC) and nitrogen (SON) and their relationships with soil properties and topographic characteristics. From the hydrological point of view, the field is isolated due to the effect of landscape features and man-made structures. Climate is continental Mediterranean with an average annual rainfall of 500 mm and soils are Calcisols. The reference inventories of 137Cs and soil nutrients were established from 21 soil samples collected in nearby undisturbed areas under typical Mediterranean vegetation cover. A total of 156 bulk soil samples (30-50 cm depth) and 156 topsoil samples (5 cm) were collected on a 10 m grid. 137Cs and soil nutrients loss and gain areas were identified by comparing the reference inventories with the values of inventories at the sampling points. A new approach to characterize and measure active (ACF) and stable (SCF) carbon fraction contents by using a dry combustion method based on the oxidation temperature of carbon fractions to analyze the SOC pool dynamics is presented in this study. A detailed field topographic survey and mapping of the spatial variability of soil properties and nutrient contents from soil analyses displayed similar spatial patterns of 137Cs and soil nutrients that also were directly and significantly correlated (p≤0.01). As much as 70% of the surface of the study field had lower values of 137Cs inventory indicating a predominance of soil loss linked to a generalized loss of soil nutrients. SOC gain was found in less than 1% of the study field and there was a large loss of SON compared to the undisturbed reference site. Higher and significant (p≤0.01) contents of soil nutrients were found in topsoil samples than in the bulk ones. Furthermore, there was an enrichment of the relative contribution of ACF to total SOC in sampling points where there was a 137Cs gain in both bulk and topsoil samples. Understanding patterns of soil nutrients can be useful for developing and implementing land management strategies to preserve soil quality in Mediterranean agricultural areas.

Soil Water Retention as Indicator for Soil Physical Quality - Examples from Two SoilTrEC European Critical Zone Observatories

NASA Astrophysics Data System (ADS)

Rousseva, Svetla; Kercheva, Milena; Shishkov, Toma; Dimitrov, Emil; Nenov, Martin; Lair, Georg J.; Moraetis, Daniel

2014-05-01

Soil water retention is of primary importance for majority of soil functions. The characteristics derived from Soil Water Retention Curve (SWRC) are directly related to soil structure and soil water regime and can be used as indicators for soil physical quality. The aim of this study is to present some parameters and relationships based on the SWRC data from the soil profiles characterising the European SoilTrEC Critical Zone Observatories Fuchsenbigl and Koiliaris. The studied soils are representative for highly productive soils managed as arable land in the frame of soil formation chronosequence at "Marchfeld" (Fuchsenbigl CZO), Austria and heavily impacted soils during centuries through intensive grazing and farming, under severe risk of desertification in context of climatic and lithological gradient at Koiliaris, Crete, Greece. Soil water retention at pF ≤ 2.52 was determined using the undisturbed soil cores (100 cm3 and 50 cm3) by a suction plate method. Water retention at pF = 4.2 was determined by a membrane press method and at pF ≥ 5.6 - by adsorption of water vapour at controlled relative humidity, both using ground soil samples. The soil physical quality parameter (S-parameter) was defined as the slope of the water retention curve at its inflection point (Dexter, 2006), determined with the obtained parameters of van Genuhten (1980) water retention equation. The S-parameter values were categorised to assess soil physical quality as follows: S < 0.020 very poor, 0.020 ≤ S < 0.035 poor, 0.035 ≤ S < 0.050 good, S ≥ 0.050 very good (Dexter, 2004). The results showed that most of the studied topsoil horizons have good physical quality according to both the S-parameter and the Plant-Available Water content (PAW), with the exception of the soils from croplands at CZO Fuxenbigl (F4, F5) which are with poor soil structure. The link between the S-parameter and the indicator of soil structure stability (water stable soil aggregates with size 1-3 mm) is not well defined. The scattering is due to high values of S in subsoil, which does not always coincide with favourable physical properties, as it can be seen from the relationship with the PAW content. It was found that values of S ≥ 0.05 correspond to PAW > 20 % vol. in the topsoil horizons. The high values of S in subsoil horizons are due to the low PAW and restrict the application of the S categories in these cases. Well defined links are found between the PAW content and the S-parameter when the data from the topsoil horizons are grouped in 2 groups according to the ratio between air-filled pores (at pF 2.52) and plant available water: <2 and ≥ 2. The authors acknowledge gratefully the European Commission Research Directorate-General for funding the SoilTrEC project (Contract No 244118) under its 7th Framework Programme.

Targeting sediment management strategies using sediment quantification and fingerprinting methods

NASA Astrophysics Data System (ADS)

Sherriff, Sophie; Rowan, John; Fenton, Owen; Jordan, Phil; hUallacháin, Daire Ó.

2016-04-01

Cost-effective sediment management is required to reduce excessive delivery of fine sediment due to intensive land uses such as agriculture, resulting in the degradation of aquatic ecosystems. Prioritising measures to mitigate dominant sediment sources is, however, challenging, as sediment loss risk is spatially and temporally variable between and within catchments. Fluctuations in sediment supply from potential sources result from variations in land uses resulting in increased erodibility where ground cover is low (e.g., cultivated, poached and compacted soils), and physical catchment characteristics controlling hydrological connectivity and transport pathways (surface and/or sub-surface). Sediment fingerprinting is an evidence-based management tool to identify sources of in-stream sediments at the catchment scale. Potential sediment sources are related to a river sediment sample, comprising a mixture of source sediments, using natural physico-chemical characteristics (or 'tracers'), and contributions are statistically un-mixed. Suspended sediment data were collected over two years at the outlet of three intensive agricultural catchments (approximately 10 km2) in Ireland. Dominant catchment characteristics were grassland on poorly-drained soils, arable on well-drained soils and arable on moderately-drained soils. High-resolution (10-min) calibrated turbidity-based suspended sediment and discharge data were combined to quantify yield. In-stream sediment samples (for fingerprinting analysis) were collected at six to twelve week intervals, using time-integrated sediment samplers. Potential sources, including stream channel banks, ditches, arable and grassland field topsoils, damaged road verges and tracks were sampled, oven-dried (<40oC) and sieved (125 microns). Soil and sediment samples were analysed for mineral magnetics, geochemistry and radionuclide tracers, particle size distribution and soil organic carbon. Tracer data were corrected to account for particle size and organic matter selectivity processes. Contributions from potential sources type groups (channel - ditches and stream banks, roads - road verges and tracks, fields - grassland and arable topsoils) were statistically un-mixed using FR2000, an uncertainty-inclusive algorithm, and combined with sediment yield data. Results showed sediment contributions from channel, field and road groups were 70%, 25% and 5% in the poorly-drained catchment, 59%, 22% and 19% in the well-drained catchment, and 17%, 74% and 9% in the moderately-drained catchment. Higher channel contributions in the poorly-drained catchment were attributed to bank erosion accelerated by the rapid diversion of surface runoff into channels, facilitated by surface and sub-surface artificial drainage networks, and bank seepage from lateral pressure gradients due to confined groundwater. Despite the greatest proportion of arable soils in the well-drained catchment, this source was frequently hydrologically disconnected as well-drained soils largely infiltrated rainfall and prevented surface soil erosion. Periods of high and intense rainfall were associated with greater proportions of field losses in the well-drained catchment likely due to infiltration exceeding the saturated hydraulic conductivity of soils and establishment of surface hydrological connectivity. Losses from field topsoils dominated in the moderately-drained catchment as antecedent soil wetness maintained surface flow pathways and coincided with low groundcover on arable soils. For cost-effective management of sediment pressures to aquatic ecosystems, catchment specific variations in sediment sources must be considered.

Exploitation of nutrient- and C-rich paleosols by deep rooting plants in Dutch drift- and coversands

NASA Astrophysics Data System (ADS)

Gocke, Martina; Kessler, Fabian; van Mourik, Jan; Jansen, Boris; Wiesenberg, Guido L. B.

2015-04-01

Plant roots are commonly assumed to be most abundant in topsoil, with strongly decreasing frequencies in underlying soil horizons with incrasing depth and almost absence of roots below the uppermost few dm due to unfavorable environmental conditions in terms of e.g. aeration, nutrient availability or water, that hamper root growth. It still remains unknown, to which extent roots might be able to exploit deeper parts of soils and underlying soil parent material as well as burried paleosols. The study site is located in SE Netherlands. Undisturbed oak forests developed about 200 years ago on stabilized driftsand, deposited on a plaggic Anthrosol after approximately 700 years of agricultural use. The soil profile, consisting of the recent initial Podzol in driftsand, overlying 1.1 m thick plaggic deposits that were established in a 0.5 m thick residual Podzol in coversand, was excavated in a pit of 2.3 m depth. Living and dead roots were counted throughout the profile on both, the vertical wall and horizontal levels. Additionally, soil or sediment samples free of visible root remains were collected in depth intervals between 0.05 m and 0.15 m from topsoil down to the coversand. A multi-proxy approach, including assessment of bulk elemental composition of soil, sediments and paleosol and molecular structure of organic matter therein, organic carbon contents, bulk density and pH was applied in order to comprehensively describe the varying environmental conditions within the soil profile and in transects from roots to root-free material. The burried agricultural soil revealed low density and high organic carbon contents compared to the coversand parent material, and especially in its lower part, high phosphorous contents. In contrast, the burried Podzol was characterized by completely different geochemical and physical properties, like increasing pH with depth and high iron and aluminium contents. In the recent initial Podzol, fine roots (≤ 2 mm), deriving from both oak trees and understory vegetation, immediately decreased from 476 m-2 to 24 m-2, whereas medium roots (2-5 mm) from oak trees continuously increased from 8 m-2 at the surface to 188 m-2 within the upper part of the agricultural soil. Both, frequencies of fine and medium roots peaked at 4.448 m-2 and 216 m-2, respectively, in the uppermost part of the burried Podzol, thus considerably exceeding topsoil abundances. Comparison of these results with those obtained at the profile wall demonstrated that fine root abundances might be considerably underestimated by the more traditional approach of profile wall investigation, because fine roots were growing vertically to exploit the nutrient-rich burried paleosols. Unlike fine roots, medium roots and even more, large roots (> 5 mm) were not able to penetrate the hard sesquioxide crusts of the burried Podzol in larger numbers. Our results show that roots are able to deeply penetrate the soil and underlying soil parent material or paleosols, if the latter provides nutrition benefits. Root distribution strongly depends on physical and chemical properties of the deep subsoil, which should be taken into account when interpreting complex soil profiles covering recent and paleosols.

Agricultural land management options after the Chernobyl and Fukushima accidents: The articulation of science, technology, and society.

PubMed

Vandenhove, Hildegarde; Turcanu, Catrinel

2016-10-01

The options adopted for recovery of agricultural land after the Chernobyl and Fukushima accidents are compared by examining their technical and socio-economic aspects. The analysis highlights commonalities such as the implementation of tillage and other types of countermeasures and differences in approach, such as preferences for topsoil removal in Fukushima and the application of K fertilizers in Chernobyl. This analysis shows that the recovery approach needs to be context-specific to best suit the physical, social, and political environment. The complex nature of the decision problem calls for a formal process for engaging stakeholders and the development of adequate decision support tools. Integr Environ Assess Manag 2016;12:662-666. © 2016 SETAC. © 2016 SETAC.

Heavy Metals in Soil&Plant System Under Conditions of the South of Tyumen Region

NASA Astrophysics Data System (ADS)

Oznobihina, A. O.; Gayevaya, E. V.

2017-11-01

The article considers the problems of pollution with heavy metals (zinc, copper, cadmium and lead) of topsoil and plant products. The article contains the results analysis for laboratory trials of the researched components of the natural environment in the territory of the reference plots of the south of the Tyumen region. The authors assessed soil pollution and the samples of natural as well as perennial grasses, rape, oats, wheat, barley with heavy metals. A correlation between the content of zinc, copper, cadmium, lead in the soil and plants growing in it was determined. The article identifies the regions where the agrotechnical procedures directed to the decrease of toxicants’ negative influence on the life form should be considered.

Hydrocarbon degradation in soils and methods for soil biotreatment.

PubMed

Morgan, P; Watkinson, R J

1989-01-01

The cleanup of soils and groundwater contaminated with hydrocarbons is of particular importance in minimizing the environmental impact of petroleum and petroleum products and in preventing contamination of potable water supplies. Consequently, there is a growing industry involved in the treatment of contaminated topsoils, subsoils, and groundwater. The biotreatment methodologies employed for decontamination are designed to enhance in situ degradation by the supply of oxygen, inorganic nutrients, and/or microbial inocula to the contaminated zone. This review considers the fate and effects of hydrocarbon contaminants in terrestrial environments, with particular reference to the factors that limit biodegradation rates. The potential efficiencies, advantages, and disadvantages of biotreatment techniques are discussed and the future research directions necessary for process development are considered.

Ecological aspects of microorganisms inhabiting uranium mill tailings

USGS Publications Warehouse

Miller, C.L.; Landa, E.R.; Updegraff, D.M.

1987-01-01

Numbers and types of microorganisms in uranium mill tailings were determined using culturing techniques. Arthrobacter were found to be the predominant microorganism inhabiting the sandy tailings, whereas Bacillus and fungi predominated in the slime tailings. Sulfate-reducing bacteria, capable of leaching radium, were isolated in low numbers from tailings samples but were isolated in significantly high numbers from topsoil in contact with the tailings. The results are placed in the context of the magnitude of uranium mill tailings in the United States, the hazards posed by the tailings, and how such hazards could be enhanced or diminished by microbial activities. Patterns in the composition of the microbial population are evaluated with respect to the ecological variables that influence microbial growth. ?? 1987 Springer-Verlag New York Inc.

The use of soil quality indicators to assess soil functionality in restored semi-arid ecosystems

NASA Astrophysics Data System (ADS)

Muñoz-Rojas, Miriam; Erickson, Todd E.; Dixon, Kingsley W.; Merritt, David J.

2016-04-01

Keywords: Pilbara, 1-day CO2 test, microbial activity, mine restoration, soil health, ecosystem services. Introduction Semi-arid and arid environments are highly vulnerable to land degradation and their restoration has commonly showed low rates of success (James et al., 2013). A systematic knowledge of soil functionality is critical to successful restoration of degraded ecosystems since approximately 80% of ecosystem services can be connected to soil functions. The assessment of soil functionality generally involves the evaluation of soil properties and processes as they relate to the ability of soil to function effectively as a component of a healthy ecosystem (Costantini et al., 2015) Using soil quality indicators may be a valuable approach to assess functionality of topsoil and novel substrates used in restoration (Muñoz-Rojas et al., 2014; 2015). A key soil chemical indicator is soil organic C, that has been widely used as an attribute of soil quality because of the many functions that it provides and supports (Willaarts et al., 2015). However, microbial indicators can be more sensitive to disturbances and could be a valuable addition in soil assessment studies in restoration programs. Here, we propose a set of soil quality indicators to assess the soil status in restored soils (topsoil and waste material) of semi-arid environments. The study was conducted during March 2015 in the Pilbara biogeographical region (northwestern Australia) at an iron ore mine site rehabilitated in 2011. Methods Soil samples were collected from two sub-areas with different soil materials used as growth media: topsoil retrieved from nearby stockpiles and a lateritic waste material utilised for its erosive stability and physical competence. An undisturbed natural shrub-grassland ecosystem dominated by Triodia spp. and Acacia spp. representative of the restored area was selected as the analogue reference site. Soil physicochemical analysis were undertaken according to standard methods. Soil microbial activity was measured with the 1-day CO2 test, a cost-effective and rapid method to determine soil microbial respiration rate based on the measurement of the CO2 burst produced after moistening dry soil (Muñoz-Rojas et al., 2016). Soil microbial abundance of specific groups was measured by phospholipid fatty acid analysis. Results and discussion We showed that in addition to organic C and C:N ratio, biological indicators (microbial diversity and activity in particular), are the most sensitive indicators to detect differences among reconstructed soils and analogue undisturbed soils in semi-arid areas. The 1-day CO2 test is an alternative cost- and time-effective method to measure microbial activity and assess soil functionality of restored soils. Our results also showed a positive effect of vegetation on reconstructed soils and a recovery of soil functionality in waste material to levels similar to topsoil once vegetation is established, although soil quality levels are still far from those in undisturbed native soils four years post-restoration. Soil functionality is critical in the restoration process, particularly in semi-arid areas, and the methods used here could be effectively applied in a broad range of restoration projects in arid and semi-arid environments. References Costantini EAC, Branquinho C, Nunes A, Schwilch G, Stavi I, Valdecantos A and Zucca C (2015) Soil indicators to assess the effectiveness of restoration strategies in dryland ecosystems. Solid Earth Discussions 7:3645-3687. James JJ, Sheley RL, EricksonT, Rollins KS, Taylor MH, Dixon KW (2013) A systems approach to restoring degraded drylands. Journal of Applied Ecology 50:730-739. Muñoz-Rojas M., Erickson T, Merritt D, Dixon K (2014) Optimising post-mining soil conditions to maximise restoration success in a biodiverse semiarid environment. Geophysical Research. Abstracts Vol. 16, EGU2014-2069-1, EGU General Assembly. Muñoz-Rojas M, Erickson T, Merritt D, Dixon K (2015) Applying soil science for restoration of post mining degraded landscapes in semi-arid Australia: challenges and opportunities. Geophysical Research. Abstracts Vol. 17, EGU2015-3967-1, EGU General Assembly. Muñoz-Rojas M, Erickson TE, Martini D, Dixon KW, Merritt DJ (2016) Soil physicochemical and microbiological indicators of short, medium and long term post-fire recovery in semi-arid ecosystems. Ecological indicators 63:14-22. Willaarts BA, Oyonarte C, Muñoz-Rojas M., Ibáñez JJ and Aguilera PA (2015) Environmental Factors Controlling Soil Organic Carbon Stocks in Two Contrasting Mediterranean Climatic Areas of Southern Spain. Land Degradation and Development (on-line). DOI: 10.1002/ldr.2417