Environmental and Cultural Impact Proposed Tennessee Colony Reservoir, Trinity River, Texas. Volume V. Appendix G.

DTIC Science & Technology

1972-01-01

allocation. Pri- marily it is concerned with any land use that increases surface water runoff and soil compaction, two phenomena that decrease recharge... runoff . Forested filter strips between range and reser- voir boundary should be developed as a land use for water quality control and quail habitat. High...shown on Plates G-10 and G-11) some measures will also be necessary to prevent fertilizer pollution of the reservoir from excessive surface runoff . G

Effect of soil compaction on the degradation and ecotoxicological impact of isoproturon

NASA Astrophysics Data System (ADS)

Mamy, L.; Vrignaud, P.; Cheviron, N.; Perreau, F.; Belkacem, M.; Brault, A.; Breuil, S.; Delarue, G.; Touton, I.; Chaplain, V.

2009-04-01

Soil is essentially a non-renewable resource which performs many functions and delivers services vital to human activities and ecosystems survival. However the capacity of soil to keep on fully performing its broad variety of crucial functions is damaged by several threats and, among them, chemical contamination by pesticides and compaction due to intensive agriculture practices. How these two threats could interact is largely unknown: compaction may modify the fate of pesticides in soil therefore their effects on the biological functioning of soil. The aim of this work was to study the effect of soil compaction on (1) the degradation of one herbicide, isoproturon (2) the ecotoxicological impact of this herbicide measured through two enzyme activities involved in C (beta-glucosidase) and N (urease) cycles in soil. Undisturbed soil cylinders were sampled in the 2-4 cm layer of La Cage experimental site (INRA, Versailles, France), under intensive agriculture practices. Several soil samples were prepared with different bulk density then treated with isoproturon (IPU). The samples were incubated at 18 ± 1°C in darkness for 63 days. At 0, 2, 7, 14, 28 and 63 days, the concentrations of isoproturon and of two of its main metabolites in soil (monodesmethyl-isoproturon, IPPMU; didesmethyl-isoproturon, IPPU), and the enzyme activities were measured. The results showed that there was no significant difference in IPU degradation under no and moderate soil compaction. IPU was less persistent in the highly compacted soil, but this soil had also higher humidity which is known to increase the degradation. Only one metabolite, IPPMU, was detected independently of the conditions of compaction. The compaction did not modify the effect of IPU on beta-glucosidase and urease activities in the long term, but microbial communities were probably the same in all the soil samples that were initially not compacted. The communities developed in durably compacted zones in the field are possibly different and modification in enzyme activities might be observed as a result. These first results seem to show that compaction did not modify the degradation and ecotoxicological impact of isoproturon in the soil. However, further studies should be performed using soil samples taken in different zones of compaction in the field, and taking into account the relation between bulk density and soil humidity.

Soil compaction effects on water status of ponderosa pine assessed through 13C/12C composition.

PubMed

Gomez, G Armando; Singer, Michael J; Powers, Robert F; Horwath, William R

2002-05-01

Soil compaction is a side effect of forest reestablishment practices resulting from use of heavy equipment and site preparation. Soil compaction often alters soil properties resulting in changes in plant-available water. The use of pressure chamber methods to assess plant water stress has two drawbacks: (1) the measurements are not integrative; and (2) the method is difficult to apply extensively to establish seasonal soil water status. We evaluated leaf carbon isotopic composition (delta13C) as a means of assessing effects of soil compaction on water status and growth of young ponderosa pine (Pinus ponderosa var. ponderosa Dougl. ex Laws) stands across a range of soil textures. Leaf delta13C in cellulose and whole foliar tissue were highly correlated. Leaf delta13C in both whole tissue and cellulose (holocellulose) was up to 1.0 per thousand lower in trees growing in non-compacted (NC) loam or clay soils than in compacted (SC) loam or clay soils. Soil compaction had the opposite effect on leaf delta13C in trees growing on sandy loam soil, indicating that compaction increased water availability in this soil type. Tree growth response to compaction also varied with soil texture, with no effect, a negative effect and a positive effect as a result of compaction of loam, clay and sandy loam soils, respectively. There was a significant correlation between 13C signature and tree growth along the range of soil textures. Leaf delta13C trends were correlated with midday stem water potentials. We conclude that leaf delta13C can be used to measure retrospective water status and to assess the impact of site preparation on tree growth. The advantage of the leaf delta13C approach is that it provides an integrative assessment of past water status in different aged leaves.

Below-ground attributes on reclaimed surface minelands over a 40-year chronosequence

NASA Astrophysics Data System (ADS)

Limb, Ryan; Bohrer, Stefanie; Volk, Jay

2017-04-01

Reclamation following mining activities often aims to restore stable soils that support productive and diverse native plant communities. The soil re-spread process increases soil compaction, which may alter soil water, plant composition, rooting depths and soil organic matter. This may have a direct impact on vegetation establishment and species recruitment. Seasonal wet/dry and freeze/thaw patterns are thought to alleviate soil compaction over time. However, this has not been formally evaluated on reclaimed landscapes at large scales. Our objectives were to (1) determine soil compaction alleviation, (2) rooting depth and (3) spatial patterns of soil water content over a time-since-reclamation gradient. Soil resistance to penetration varied by depth, with shallow compaction remaining unchanged, but deeper compaction increased over time rather than being alleviated. Root biomass and depth did not increase with time and was consistently less than reference locations. Plant communities initially had a strong native component, but quickly became dominated by invasive species following reclamation and soil water content became increasingly homogeneous over the 40-year chronosequence. Seasonal weather patterns and soil organic matter additions can reduce soil compaction if water infiltration is not limited. Shallow and strongly fibrous-rooted grasses present in reclaimed sites added organic matter to shallow soil layers, but did not penetrate the compacted layers and allow water infiltration. Strong linkages between land management strategies, soil properties and vegetation composition can advance reclamation efforts and promote heterogeneous landscapes. However, current post-reclamation management strategies are not facilitating natural seasonal weather patterns to reducing soil compaction.

Recovery of severely compacted soils in the Mojave Desert, California, USA

USGS Publications Warehouse

Webb, R.H.

2002-01-01

Often as a result of large-scale military maneuvers in the past, many soils in the Mojave Desert are highly vulnerable to soil compaction, particularly when wet. Previous studies indicate that natural recovery of severely compacted desert soils is extremely slow, and some researchers have suggested that subsurface compaction may not recover. Poorly sorted soils, particularly those with a loamy sand texture, are most vulnerable to soil compaction, and these soils are the most common in alluvial fans of the Mojave Desert. Recovery of compacted soil is expected to vary as a function of precipitation amounts, wetting-and-drying cycles, freeze-thaw cycles, and bioturbation, particularly root growth. Compaction recovery, as estimated using penetration depth and bulk density, was measured at 19 sites with 32 site-time combinations, including the former World War II Army sites of Camps Ibis, Granite, Iron Mountain, Clipper, and Essex. Although compaction at these sites was caused by a wide variety of forces, ranging from human trampling to tank traffic, the data do not allow segregation of differences in recovery rates for different compaction forces. The recovery rate appears to be logarithmic, with the highest rate of change occurring in the first few decades following abandonment. Some higher-elevation sites have completely recovered from soil compaction after 70 years. Using a linear model of recovery, the full recovery time ranges from 92 to 100 years; using a logarithmic model, which asymptotically approaches full recovery, the time required for 85% recovery ranges from 105-124 years.

Soil compaction and organic matter affect conifer seedling nonmycorrhizal and ectomycorrhizal root tip abundance and diversity.

Treesearch

Michael P. Amaranthus; Debbie Page-Dumroese; Al Harvey; Efren Cazares; Larry F. Bednar

1996-01-01

Three levels of organic matter removal (bole only; bole and crowns; and bole, crowns, and forest floor) and three levels of mechanical soil compaction (no compaction, moderate compaction, and severe soil compaction) were studied as they influence Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco) and western white...

Soil compaction effects on growth of young ponderosa pine following litter removal in California's Sierra Nevada

Treesearch

A. Gomez; R. F. Powers; M. J. Singer; W. R. Horwath

2002-01-01

Increased use of heavy equipment and more frequent entry into forest stands has increased the potential for soil compaction and decreased productivity. We examined compaction and tree growth relationships on three California soils of contrasting textures (clayey, loamy, and sandy loam) on plots from which the organic soil horizon had been removed. Compacted and...

Can differences in root responses to soil drying and compaction explain differences in performance of trees growing on landfill sites?

PubMed

Liang, Jiansheng; Zhang, Jianhua; Chan, Gilbert Y. S.; Wong, M. H.

1999-07-01

Two tropical woody species, Acacia confusa Merrill and Litsea glutinosa (Lour.) C.B. Robinson, were grown under controlled conditions in PVC pipes filled with John Innes No. 2 soil. To investigate root distribution, physiological characteristics and hydraulic conductivity, four soil treatments were imposed-well-watered and noncompacted (control), well-watered and compacted; unwatered and noncompacted, and unwatered and compacted. In L. glutinosa, rooting depth and root elongation were severely restricted when soil bulk density increased from around 1.12 to 1.62 g cm(-3), whereas soil compaction had little effect on these parameters in A. confusa. As soil drying progressed, root water potential and osmotic potential declined more slowly in L. glutinosa than in A. confusa. Both the soil drying and compaction treatments significantly stimulated the accumulation of root abscisic acid (ABA) in both species. Soil drying damaged the root cell membrane of A. confusa, but had little influence on the root cell membrane of L. glutinosa. Soil drying had a greater effect on root hydraulic conductivity (L(p)) in L. glutinosa than in A. confusa, whereas the effect of soil compaction on L(p) was less in L. glutinosa than in A. confusa. Soil drying enhanced the effects of soil compaction on root L(p). We conclude that soil drying and compaction have large species-specific effects on the distribution, growth and physiology of roots. The relationships of these root properties to the species' ability to tolerate unfavorable soil conditions were examined.

Immediate and long term effects of compaction on the stress-strain behaviour of soil

NASA Astrophysics Data System (ADS)

Noor, Sarah T.; Chowdhury, Prantick; Chowdhury, Tasnim

2018-04-01

This paper explores whether delay in construction after compaction can benefit from the gain in soil’s strength and stability point of view. An experimental investigation has been carried out to examine the gradual development of soil’s shear strength by ageing of mechanically compacted soil at three relative densities. In order to separate the gain in strength due to ageing from that occurring from the reduction in soil moisture, the soil samples prepared in moulds were kept in desiccators for different periods of time (1, 9 and 17 days) before testing unconfined compressive strength test. The soil in densely compacted state is found to gain in strength due to ageing faster than that in medium compacted state. Only due to ageing of 9 days or more, unconfined compressive strength of compacted soil is found about 1.7 to 2.4 times of that attained in day 1 after compaction.

Surface compaction estimates and soil sensitivity in Aspen stands of the Great Lakes States

Treesearch

Aaron Steber; Ken Brooks; Charles H. Perry; Randy Kolka

2007-01-01

Aspen forests in the Great Lakes States support much of the regional timber industry. Management-induced soil compaction is a concern because it affects forest health and productivity and soil erosion. Soil compaction increases bulk density and soil strength and can also decrease air and water movement into and through the soil profile. Currently, most inventories, and...

Environmental impacts of different crop rotations in terms of soil compaction.

PubMed

Götze, Philipp; Rücknagel, Jan; Jacobs, Anna; Märländer, Bernward; Koch, Heinz-Josef; Christen, Olaf

2016-10-01

Avoiding soil compaction caused by agricultural management is a key aim of sustainable land management, and the soil compaction risk should be considered when assessing the environmental impacts of land use systems. Therefore this project compares different crop rotations in terms of soil structure and the soil compaction risk. It is based on a field trial in Germany, in which the crop rotations (i) silage maize (SM) monoculture, (ii) catch crop mustard (Mu)_sugar beet (SB)-winter wheat (WW)-WW, (iii) Mu_SM-WW-WW and (iv) SB-WW-Mu_SM are established since 2010. Based on the cultivation dates, the operation specific soil compaction risks and the soil compaction risk of the entire crop rotations are modelled at two soil depths (20 and 35 cm). To this end, based on assumptions of the equipment currently used in practice by a model farm, two scenarios are modelled (100 and 50% hopper load for SB and WW harvest). In addition, after one complete rotation, in 2013 and in 2014, the physical soil parameters saturated hydraulic conductivity (kS) and air capacity (AC) were determined at soil depths 2-8, 12-18, 22-28 and 32-38 cm in order to quantify the soil structure. At both soil depths, the modelled soil compaction risks for the crop rotations including SB (Mu_SB-WW-WW, SB-WW-Mu_SM) are higher (20 cm: medium to very high risks; 35 cm: no to medium risks) than for those without SB (SM monoculture, Mu_SM-WW-WW; 20 cm: medium risks; 35 cm: no to low risks). This increased soil compaction risk is largely influenced by the SB harvest in years where soil water content is high. Halving the hopper load and adjusting the tyre inflation pressure reduces the soil compaction risk for the crop rotation as a whole. Under these conditions, there are no to low soil compaction risks for all variants in the subsoil (soil depth 35 cm). Soil structure is mainly influenced in the topsoil (2-8 cm) related to the cultivation of Mu as a catch crop and WW as a preceding crop. Concerning kS, Mu_SB-WW-WW (240 cm d(-1)) and Mu_SM-WW-WW (196 cm d(-1)) displayed significantly higher values than the SM monoculture (67 cm d(-1)), indicating better structural stability and infiltration capacity. At other soil depths, and for the parameter AC, there are no systematic differences in soil structure between the variants. Under the circumstances described, all crop rotations investigated are not associated with environmental impacts caused by soil compaction. Copyright © 2016 Elsevier Ltd. All rights reserved.

Investigating the Effect of Compaction Characteristics on the Erodibility of Cohesive Soils Using the JET Method

NASA Astrophysics Data System (ADS)

Asghari Tabrizi, A.; LaRocque, L. A.; Chaudhry, M.; Imran, J.

2013-12-01

Several flood disasters occur every year all over the world, mostly due to levee and dam failure which result in human fatalities as well as devastating economic damages. To model and predict earthen embankment failures for the preparation of emergency action plans and risk assessments, the soil erodibility by flowing water is an essential parameter. The determination of erodibility becomes even more complicated for cohesive soils because of the large number of parameters controlling their erosion behavior (e.g. clay content, plasticity, compaction effort, compaction water content) and the difficulty of estimating these parameters. In this study the effect of the compaction energy and compaction water content on the erodibility of a sandy loam soil was assessed. Soil samples were prepared in a standard diameter compaction mold, 101.6 mm, for three levels of compaction effort and water content (i.e. low, medium, and high) with two replications for each case (18 tests total) and examined using the jet erosion test (JET). Observations from qualitative and statistical analyses of the data are: 1) a wide range of erodibility, from very erodible to very resistant, was produced by changes in the compaction characteristics; 2) for a given compaction energy, the erosion resistance based on the detachment rate coefficient kd tends to become minimum near the optimum compaction water content. On the dry side of optimum compaction water content, kd decreases with steep gradients by increasing the water content, while it increases with a flatter gradient on the wet side; 3) At a given water content, the soil erosion resistance increases with compaction efforts; 4) compaction water content influences soil erosibility more than compaction energy, especially on the dry side of the optimum compaction water content; and 5) for a given compaction effort, the critical shear stress increases with water content up to an optimum water content and then it decreases which is in consistent with the kd trends.

Impact of abiotic factors on development of the community of arbuscular mycorrhizal fungi in the soil: a Review

NASA Astrophysics Data System (ADS)

Jamiołkowska, Agnieszka; Księżniak, Andrzej; Gałązka, Anna; Hetman, Beata; Kopacki, Marek; Skwaryło-Bednarz, Barbara

2018-01-01

Arbuscular mycorrhizal fungi inhabiting soil play an important role for vascular plants. Interaction between arbuscular mycorrhizal fungi, plants and soil microorganisms leads to many mutual advantages. However, the effectiveness of mycorrhizal fungi depends not only on biotic, but also abiotic factors such as physico-chemical properties of the soil, availability of water and biogenic elements, agricultural practices, and climatic conditions. First of all, it is important to adapt the arbuscular mycorrhizal fungi species to changing environmental conditions. The compactness of the soil and its structure have a huge impact on its biological activity. Soil pH reaction has a substantial impact on the mobility of ions in soil dilutions and their uptake by plants and soil microflora. Water excess can be a factor negatively affecting arbuscular mycorrhizal fungi because these microorganisms are sensitive to a lower availability of oxygen. Mechanical cultivation of the soil has a marginal impact on the arbuscular mycorrhizal fungi spores. However, soil translocation can cause changes to the population of the arbuscular mycorrhizal fungi abundance in the soil profile. The geographical location and topographic differentiation of cultivated soils, as well as the variability of climatic factors affect the population of the arbuscular mycorrhizal fungi in the soils and their symbiotic activity.

Measuring the response of conifer seedlings to soil compaction stress

Treesearch

Howard G. Halverson; Robert P. Zisa

1982-01-01

A test of seedling growth response to several levels of soil compaction showed that root penetration depth was best correlated with soil compaction. Shoot biomass, root biomass, root elongation, and seedling height were not well correlated with compaction. The results reveal that most measurements of growth do not give a good indication of seedling response to stresses...

Conifer root proliferation after 20 years of soil compaction

Treesearch

Matt D. Busse; Gary O. Fiddler; Carol J. Shestak

2017-01-01

Soil compaction is known to limit plant growth by reducing soil macroporosity and restricting gas, water, and root movement. Recent evidence from study sites across the United States and Canada, however, suggests that tree growth is not universally affected by soil compaction from forest harvesting practices. Our observational study examined rooting patterns in mixed...

Impact of Site Disturbances from Harvesting and Logging on Soil Physical Properties and Pinus kesiya Tree Growth.

PubMed

Missanjo, Edward; Kamanga-Thole, Gift

2014-01-01

A study was conducted to determine the impacts of soil disturbance and compaction on soil physical properties and tree growth and the effectiveness of tillage in maintaining or enhancing site productivity for intensively managed Pinus kesiya Royle ex Gordon sites in Dedza, Malawi. The results indicate that about fifty-two percent of the area of compacted plots was affected by the vehicular traffic. Seventy percent of the trees were planted on microsites with some degree of soil disturbance. Soil bulk density at 0-20 cm depth increased from 0.45 to 0.66 Mg m(-3) in the most compacted portions of traffic lanes. Soil strength in traffic lanes increased at all 60 cm depth but never exceeded 1200 kPa. Volumetric soil water content in compacted traffic lanes was greater than that in noncompacted soil. Total soil porosity decreased 13.8% to 16.1% with compaction, while available water holding capacity increased. The study revealed no detrimental effects on tree height and diameter from soil disturbance or compaction throughout the three growing season. At the ages of two and three, a tree volume index was actually greater for trees planted on traffic lanes than those on nondisturbed soil.

Impact of Site Disturbances from Harvesting and Logging on Soil Physical Properties and Pinus kesiya Tree Growth

PubMed Central

Missanjo, Edward

2014-01-01

A study was conducted to determine the impacts of soil disturbance and compaction on soil physical properties and tree growth and the effectiveness of tillage in maintaining or enhancing site productivity for intensively managed Pinus kesiya Royle ex Gordon sites in Dedza, Malawi. The results indicate that about fifty-two percent of the area of compacted plots was affected by the vehicular traffic. Seventy percent of the trees were planted on microsites with some degree of soil disturbance. Soil bulk density at 0–20 cm depth increased from 0.45 to 0.66 Mg m−3 in the most compacted portions of traffic lanes. Soil strength in traffic lanes increased at all 60 cm depth but never exceeded 1200 kPa. Volumetric soil water content in compacted traffic lanes was greater than that in noncompacted soil. Total soil porosity decreased 13.8% to 16.1% with compaction, while available water holding capacity increased. The study revealed no detrimental effects on tree height and diameter from soil disturbance or compaction throughout the three growing season. At the ages of two and three, a tree volume index was actually greater for trees planted on traffic lanes than those on nondisturbed soil. PMID:27355043

Effect of soil structure on the growth of bacteria in soil quantified using CARD-FISH

NASA Astrophysics Data System (ADS)

Juyal, Archana; Eickhorst, Thilo; Falconer, Ruth; Otten, Wilfred

2014-05-01

It has been reported that compaction of soil due to use of heavy machinery has resulted in the reduction of crop yield. Compaction affects the physical properties of soil such as bulk density, soil strength and porosity. This causes an alteration in the soil structure which limits the mobility of nutrients, water and air infiltration and root penetration in soil. Several studies have been conducted to explore the effect of soil compaction on plant growth and development. However, there is scant information on the effect of soil compaction on the microbial community and its activities in soil. Understanding the effect of soil compaction on microbial community is essential as microbial activities are very sensitive to abrupt environmental changes in soil. Therefore, the aim of this work was to investigate the effect of soil structure on growth of bacteria in soil. The bulk density of soil was used as a soil physical parameter to quantify the effect of soil compaction. To detect and quantify bacteria in soil the method of catalyzed reporter deposition-fluorescence in situ hybridization (CARD-FISH) was used. This technique results in high intensity fluorescent signals which make it easy to quantify bacteria against high levels of autofluorescence emitted by soil particles and organic matter. In this study, bacterial strains Pseudomonas fluorescens SBW25 and Bacillus subtilis DSM10 were used. Soils of aggregate size 2-1mm were packed at five different bulk densities in polyethylene rings (4.25 cm3).The soil rings were sampled at four different days. Results showed that the total number of bacteria counts was reduced significantly (P

Soil compaction and organic matter affect conifer seedling nonmycorrhizal and ectomycorrhizal root tip abundance and diversity. Forest Service research paper

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

Amaranthus, M.P.; Page-Dumroese, D.; Harvey, A.

1996-05-01

Three levels of organic matter removal (bole only; bole and crowns; and bole, crowns, and forest floor) and three levels of mechanical soil compaction (no compaction, moderate compaction, and severe soil compaction) were studied as they influence Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco) and western white pine (Pinus monticola Dougl. ex D. Don) seedlings following outplanting. Moderate and severe soil compaction significantly reduced nonmycorrhizal root tip abundance on both Douglas-fir and western white pine seedlings (p less than or equal to 0.05). Ectomycorrhizal root tip abundance was significantly reduced on Douglas-fir seedlings in severely compacted areas with bole andmore » crowns and bole, crowns, and forest floor removed. Ectomycorrhizal diversity also was significantly reduced on Douglas-fir seedlings in all severely compacted areas.« less

Soil compaction--indicators for the assessment of harmful changes to the soil in the context of the German Federal Soil Protection Act.

PubMed

Lebert, Matthias; Böken, Holger; Glante, Frank

2007-02-01

Soil compaction in agriculture induced by large-scale equipment is of growing concern. Heavy wheel loads used in arable cropping have the potential to cause irreversible damage to the subsoil structure and may lead to harmful soil compaction. In order to sustain or improve soil health or fitness on a sustainable basis, indicators are needed to assess the changes in the soil structure and the respective soil functions. This requires an adequate verification of methods for distinguishing between the impairment of soil structure and the disruption of soil functions, and for the respective subject of protection. In this article the link between existing models of soil physical prognosis, practical guidelines, and criteria for the identification of affected soil structure is demonstrated, and a viable concept to distinguish harmful changes to the soil is presented. The concept consists of methods for soil physical analysis such as "pre-compression stress" and "loading ratio", practical recommendations for best management practice, and an indicator-based model for the identification of harmful subsoil compaction derived from a research project for the German Federal Environmental Agency, making it possible to determine for a respective location the required level of action far beyond the common practice of precautions against harmful soil compaction.

Experimental study of nonlinear ultrasonic behavior of soil materials during the compaction.

PubMed

Chen, Jun; Wang, Hao; Yao, Yangping

2016-07-01

In this paper, the nonlinear ultrasonic behavior of unconsolidated granular medium - soil during the compaction is experimentally studied. The second harmonic generation technique is adopted to investigate the change of microstructural void in materials during the compaction process of loose soils. The nonlinear parameter is measured with the change of two important environmental factors i.e. moisture content and impact energy of compaction. It is found the nonlinear parameter of soil material presents a similar variation pattern with the void ratio of soil samples, corresponding to the increased moisture content and impact energy. A same optimum moisture content is found by observing the variation of nonlinear parameter and void ratio with respect to moisture content. The results indicate that the unconsolidated soil is manipulated by a strong material nonlinearity during the compaction procedure. The developed experimental technique based on the second harmonic generation could be a fast and convenient testing method for the determination of optimum moisture content of soil materials, which is very useful for the better compaction effect of filled embankment for civil infrastructures in-situ. Copyright © 2016 Elsevier B.V. All rights reserved.

Yarding-method and slash-treatment effects on compaction, humus, and variation in plantation soils.

Treesearch

Don Minore; Howard G. Weatherly

1988-01-01

Soil penetration-resistance and soil-humus frequency were measured on 86 progeny-test plantations in southwestern Oregon to determine the effects of yarding method and slash treatment on soil compaction and humus, and a disturbance index was calculated for each plantation. Compaction and humus loss were more severe on tractor-yarded, machine-piled plantations than on...

Assessment of soil compaction properties based on surface wave techniques

NASA Astrophysics Data System (ADS)

Jihan Syamimi Jafri, Nur; Rahim, Mohd Asri Ab; Zahid, Mohd Zulham Affandi Mohd; Faizah Bawadi, Nor; Munsif Ahmad, Muhammad; Faizal Mansor, Ahmad; Omar, Wan Mohd Sabki Wan

2018-03-01

Soil compaction plays an important role in every construction activities to reduce risks of any damage. Traditionally, methods of assessing compaction include field tests and invasive penetration tests for compacted areas have great limitations, which caused time-consuming in evaluating large areas. Thus, this study proposed the possibility of using non-invasive surface wave method like Multi-channel Analysis of Surface Wave (MASW) as a useful tool for assessing soil compaction. The aim of this study was to determine the shear wave velocity profiles and field density of compacted soils under varying compaction efforts by using MASW method. Pre and post compaction of MASW survey were conducted at Pauh Campus, UniMAP after applying rolling compaction with variation of passes (2, 6 and 10). Each seismic data was recorded by GEODE seismograph. Sand replacement test was conducted for each survey line to obtain the field density data. All seismic data were processed using SeisImager/SW software. The results show the shear wave velocity profiles increase with the number of passes from 0 to 6 passes, but decrease after 10 passes. This method could attract the interest of geotechnical community, as it can be an alternative tool to the standard test for assessing of soil compaction in the field operation.

Evaluation of Revised Manual Compaction Rammers and Laboratory Compaction Procedures.

DTIC Science & Technology

1983-09-01

in soil preparation procedure.* The soils being tested in this investigation were classified as MH and were known to contain halloysite clay mineral...soils containing halloysite on the results of compaction tests (Frost 1967, Brand and Hongsnoi 1969). It has also been shown that air-drying and then

Recovery of compacted soils in Mojave Desert ghost towns.

USGS Publications Warehouse

Webb, R.H.; Steiger, J.W.; Wilshire, H.G.

1986-01-01

Residual compaction of soils was measured at seven sites in five Mojave Desert ghost towns. Soils in these Death Valley National Monument townsites were compacted by vehicles, animals, and human trampling, and the townsites had been completely abandoned and the buildings removed for 64 to 75 yr. Recovery times extrapolated using a linear recovery model ranged from 80 to 140 yr and averaged 100 yr. The recovery times were related to elevation, suggesting freeze-thaw loosening as an important factor in ameliorating soil compaction in the Mojave Desert. -from Authors

Improvement of Base and Soil Construction Quality by Using Intelligent Compaction Technology : Final Report.

DOT National Transportation Integrated Search

2017-08-01

Intelligent Compaction (IC) technique is a fast-developing technology for base and soil compaction quality control. Proof-rolling subgrades and bases using IC rollers upon completion of compaction can identify the less stiff spots and significantly i...

Assessment of soil strength variability in a havested loblolly pine plantation in the Piedmont region of Alabama, United States

Treesearch

Emily Carter; Tim McDonald; John Torbert

2000-01-01

Mechanised forest harvest operations are a significant source of soil compaction for which intensive tillage is prescribed to alleviate soil compaction and ensure successful regeneration of planted pine trees. Soil strength is a poiential indicator of compaction status of a harvest tract due to its sensitivity and the ease of data collection with a cone penetrometer,...

Quantifying the heterogeneity of soil compaction, physical soil properties and soil moisture across multiple spatial scales

NASA Astrophysics Data System (ADS)

Coates, Victoria; Pattison, Ian; Sander, Graham

2016-04-01

England's rural landscape is dominated by pastoral agriculture, with 40% of land cover classified as either improved or semi-natural grassland according to the Land Cover Map 2007. Since the Second World War the intensification of agriculture has resulted in greater levels of soil compaction, associated with higher stocking densities in fields. Locally compaction has led to loss of soil storage and an increased in levels of ponding in fields. At the catchment scale soil compaction has been hypothesised to contribute to increased flood risk. Previous research (Pattison, 2011) on a 40km2 catchment (Dacre Beck, Lake District, UK) has shown that when soil characteristics are homogeneously parameterised in a hydrological model, downstream peak discharges can be 65% higher for a heavy compacted soil than for a lightly compacted soil. However, at the catchment scale there is likely to be a significant amount of variability in compaction levels within and between fields, due to multiple controlling factors. This research focusses in on one specific type of land use (permanent pasture with cattle grazing) and areas of activity within the field (feeding area, field gate, tree shelter, open field area). The aim was to determine if the soil characteristics and soil compaction levels are homogeneous in the four areas of the field. Also, to determine if these levels stayed the same over the course of the year, or if there were differences at the end of the dry (October) and wet (April) periods. Field experiments were conducted in the River Skell catchment, in Yorkshire, UK, which has an area of 120km2. The dynamic cone penetrometer was used to determine the structural properties of the soil, soil samples were collected to assess the bulk density, organic matter content and permeability in the laboratory and the Hydrosense II was used to determine the soil moisture content in the topsoil. Penetration results show that the tree shelter is the most compacted and the open field area is least compacted in both periods. The falling head test showed that soil permeability was lowest around the feeding area and highest in the open field area in both periods. Laboratory tests showed that the tree shelter had the lowest bulk density values, due to the higher levels of organic matter content and the field gate had the highest levels of bulk density in both periods. There was also a significant difference in bulk density at the field gate and open field areas between the two periods. These results highlight statistically significant differences between heavily compacted areas where animals congregate and less-trampled areas of the field.

The effect of mulching and soil compaction on fungi composition and microbial communities in the rhizosphere of soybean

NASA Astrophysics Data System (ADS)

Frac, M.; Siczek, A.; Lipiec, J.

2009-04-01

The soil environment is the habitat of pathogenic and saprotrophic microorganisms. The composition of the microbial community are related to biotic and abiotic factors, such as root exudates, crop residues, climate factors, mulching, mineral fertilization, pesticides introduction and soil compaction. The aim of the study was to determine the effect of the mulching and soil compaction on the microorganism communities in the rhizosphere soil of soybean. The studies were carried out on silty loam soil (Orthic Luvisol) developed from loess (Lublin, Poland). The experiment area was 192m2 divided into 3 sections consisted of 6 micro-plots (7m2). Three levels of soil compaction low, medium and heavy obtained through tractor passes were compared. The soil was compacted and loosened within seedbed layer 2 weeks before sowing. Soybean "Aldana" seeds were inoculated with Bradyrhizobium japonicum and were sown with interrow spacing of 0.3m. Wheat straw (as mulch) was uniformly spread on the half of each micro-plot at an amount of 0.5kg m-1 after sowing. Rhizosphere was collected three times during growing season of soybean. Microbiological analyses were conducted in 3 replications and included the determination of: the total number of bacteria and fungi, the number of bacteria Pseudomonas sp. and Bacillus sp., the genus identification of fungi isolated from rhizosphere of soybean. Results indicated a positive effect of mulching on the increase number of all groups of examined rhizosphere microorganisms (fungi, bacteria, Pseudomonas sp., Bacillus sp.). The highest number of the microorganisms was found in the low and medium compacted soil and markedly decreased in the most compacted soil. Relatively high number of antagonistic fungi (Penicillium sp., Trichoderma sp.) was recorded in the rhizosphere of low and medium compacted soil, particularly in mulched plots. The presence of these fungi can testify to considerable biological activity, which contributes to the improvement of the phytosanitary condition of the soil. However, the decrease of the antagonistic microorganism number in the heavy compacted soil can be responsible for appearance higher number of the potentially phytopathogenic fungi (Fusarium sp., Phoma sp.). Further research, with using molecular technique, will help better understanding interactions between plant and microorganisms in the soybean rhizosphere under different soil management conditions.

Soil compaction related to grazing and its effects on herbaceous roots frequency and soil organic matter content in rangelands of SW Spain

NASA Astrophysics Data System (ADS)

Pulido, Manuel; Schnabel, Susanne; Francisco Lavado Contador, Joaquín; Miralles Mellado, Isabel

2016-04-01

Rangelands in SW Spain occupy a total surface area of approximately 6 million ha and constitute the most representative extensive ranching system of the Iberian Peninsula gathering more than 13 million livestock heads. They are characterised by an herbaceous layer, mostly composed of therophytic species, with a disperse tree cover, mainly holm oak and cork oak (Quercus ilex rotundifolia and Q. suber), interspersed with shrubs in many places. This type of land system is of ancient origin and experienced frequent changes in land use in the past, since agricultural, livestock and forestry activities have coexisted within the same farms. In recent decades, livestock farming has become dominant due, in part, to the subsidies of the Common Agriculture Policy. Since Spain joined the European Union in 1986 until the year 2000, the number of domestic animals doubled, particularly cattle, and consequently animal stocking rates have increased on average from 0.40 AU ha-1 up to 0.70 AU ha-1. This increase in animal stocking rates, along with a progressive substitution of cattle instead of sheep in many farms, has led to the occurrence of land degradation processes such as the reduction of grass cover or soil compaction in heavily grazed areas. Previous research has evidenced higher values of soil bulk density and resistance to penetration as well as larger bare surface areas in spring in fenced areas with animal stocking rates above 1 AU ha-1. However, a better understanding of how increasing bulk density or resistance to penetration influence the frequency of herbaceous roots and how a reduction in the frequency of roots affects soil organic matter content in rangelands is still unknown. Therefore, the main goal of this study was to determine possible relationships between the frequencies of herbaceous roots and soil organic matter content in order to understand the effect of excessive animal numbers on the depletion of soil fertility by reducing progressively the quantity of roots. The study was carried out in 22 fenced areas belonging to 10 privately-owned farms grazed under different intensities (range: 0.19 - 15.76 AU ha-1 year-1). A total number of 597 undisturbed core samples and 311 bulk samples were collected in order to determine bulk density and soil organic matter content, among other many properties. Resistance to soil penetration was quantified using Eijkelkamp Penetrologger in 890 random points at different depth (0-80 cm) and soil moisture content (dry and wet). The frequency of herbaceous roots was estimated for each soil horizon in 47 soil profiles, described according to FAO and categorized in 4 classes: none-few, common, abundant and many. All variables were pair-wise correlated and their mean values were compared between the different classes of root frequency. Results showed an inverse relationship between soil resistance to penetration and the frequency of herbaceous roots, i.e. the amount of roots lower in soils with high resistance to penetration. Soil horizons with none or few, common, abundant and many roots averaged 0.74%, 1.27%, 2.23% and 2.70% of SOM, respectively, showing significant differences between groups. Furthermore, SOM showed negative coefficients of correlation with resistance to penetration under dry (r=-0.34, p<0.05) and under wet conditions (r=-0.11, p<0.05) and bulk density (r=-0.31, p<0.05). The values herein observed confirm that soil compaction provoked by an excessive number of animals can decrease the content of soil organic matter by reducing the quantity of herbaceous roots although further research is still needed.

Assessing the environmental impacts of soil compaction in Life Cycle Assessment.

PubMed

Stoessel, Franziska; Sonderegger, Thomas; Bayer, Peter; Hellweg, Stefanie

2018-07-15

Maintaining biotic capacity is of key importance with regard to global food and biomass provision. One reason for productivity loss is soil compaction. In this paper, we use a statistical empirical model to assess long-term yield losses through soil compaction in a regionalized manner, with global coverage and for different agricultural production systems. To facilitate the application of the model, we provide an extensive dataset including crop production data (with 81 crops and corresponding production systems), related machinery application, as well as regionalized soil texture and soil moisture data. Yield loss is modeled for different levels of soil depth (0-25cm, 25-40cm and >40cm depth). This is of particular relevance since compaction in topsoil is classified as reversible in the short term (approximately four years), while recovery of subsoil layers takes much longer. We derive characterization factors quantifying the future average annual yield loss as a fraction of the current yield for 100years and applicable in Life Cycle Assessment studies of agricultural production. The results show that crops requiring enhanced machinery inputs, such as potatoes, have a major influence on soil compaction and yield losses, while differences between mechanized production systems (organic and integrated production) are small. The spatial variations of soil moisture and clay content are reflected in the results showing global hotspot regions especially susceptible to soil compaction, e.g. the South of Brazil, the Caribbean Islands, Central Africa, and the Maharashtra district of India. The impacts of soil compaction can be substantial, with highest annual yield losses in the range of 0.5% (95% percentile) due to one year of potato production (cumulated over 100y this corresponds to a one-time loss of 50% of the present yield). These modeling results demonstrate the necessity for including soil compaction effects in Life Cycle Impact Assessment. Copyright © 2018 Elsevier B.V. All rights reserved.

Using Conservation Systems to Alleviate Soil Compaction in a Southeastern United States Ultisol

USDA-ARS?s Scientific Manuscript database

Coastal Plain soils are prone to compaction and tend to form hardpans which restrict root growth and reduce yields. The adoption of non-inversion deep tillage has been recommended to disrupt compacted soil layers and create an adequate medium for crop development. In spite of its efficacy, increased...

Soil compaction associated with cut-to-length and whole-tree harvesting of a coniferous forest

Treesearch

Sang-Kyun Han; Han Han-Sup; Deborah Page-Dumroese; Leonard R. Johnson

2009-01-01

The degree and extent of soil compaction, which may reduce productivity of forest soils, is believed to vary by the type of harvesting system, and a field-based study was conducted to compare soil compaction from cut-to-length (CTL) and whole-tree (WT) harvesting operations. The CTL harvesting system used less area to transport logs to the landings than did the WT...

An approach for modeling the influence of wheel tractor loads and vibration frequencies on soil compaction

NASA Astrophysics Data System (ADS)

Verotti, M.; Servadio, P.; Belfiore, N. P.; Bergonzoli, S.

2012-04-01

Both soil compaction and ground vibration are forms of environmental degradation that may be understood in the context of the vehicle-soil interaction process considered (Hildebrand et al., 2008). The transit of tractors on agricultural soil is often the main cause of soil compaction increasing. As known, this can be a serious problems for tillage and sowing and therefore the influence of all the affecting factors have been extensively studied in the last decades in order to understand their impact on the biosystem. There are factors related to the climate, namely to the rainfalls and temperature, and many others. Hence, it is not simple to figure out a complete model for predicting an index of compaction, for a given situation. Soil compaction models are important tools for controlling soil compaction due to agricultural field traffic and they are potentially useful technique to provide information concerning correct soil management. By means of such models, strategies and recommendations for prevention of soil compaction may be developed and specific advice may be given to farmers and advisers. In order to predict field wheeled and tracked vehicle performance, some empirical methods, used for off-road vehicle, were applied by Servadio (2010) on agricultural soil. The empirical indexes included, besides the soil strength, the load carried by the tire or track, some technical characteristics of the tire or track of the vehicle (tire or track width, tire or track wheel diameter, unloaded tire section height, number of wheel station in one track, tire deflection, total length of the belt track, the track pitch) as well as the vehicle passes. They have been validated with the tests results of agricultural vehicles over a range of soil in central Italy. Among the parameters which affect soil compaction, the water content of the soil, the axle load and number of vehicle passes proved to be the most important ones. The present paper concerns mainly vehicle-soil-man interaction. In particular, a model based on elasto-visco-plastic concentrated parameters, with multiple degrees of freedom, will be used in order to build a method for detecting a soil damage index, especially expressed in terms of increasing of soil compaction. Besides the axle load, the model will take into account the frequency of the vibrations that the vehicle is transmitting to the soil. Such model expresses a numerical value for the transmissibility coefficient and also allows evaluating the damage at the surface and on the bulk medium where the agricultural crops initially develop. Key words: vehicle-soil interaction, vibration, compaction, models. Acknowledgements This work was carried out under the auspices of the special project "Sceneries of adaptation of the Italian agriculture to the climatic changes" (AGROSCENARI) of the Agricultural Research Council, and Italian Ministry of the Agricultural and Forestry Politics.

Composition and structure of aggregates from compacted soil horizons in the southern steppe zone of European Russia

NASA Astrophysics Data System (ADS)

Sorokin, A. S.; Abrosimov, K. N.; Lebedeva, M. P.; Kust, G. S.

2016-03-01

The composition and structure of aggregates from different agrogenic soils in the southern steppe zone of European Russia have been studied. It is shown that the multi-level study (from the macro- to microlevel) of these horizons makes it possible to identify soil compaction caused by different elementary soil processes: solonetz-forming, vertisol-forming, and mechanical (wheel) compaction in the rainfed and irrigated soils. The understanding of the genesis of the compaction of soil horizons (natural or anthropogenic) is important for the economic evaluation of soil degradation. It should enable us to make more exact predictions of the rates of degradation processes and undertake adequate mitigation measures. The combined tomographic and micromorphological studies of aggregates of 1-2 and 3-5 mm in diameter from compacted horizons of different soils have been performed for the first time. Additional diagnostic features of negative solonetz- forming processes (low open porosity of aggregates seen on tomograms and filling of a considerable part of the intraped pores with mobile substance) and the vertisol-forming processes (large amount of fine intraaggregate pores seen on tomograms and a virtual absence of humus-clay plasma in the intraped zone)—have been identified. It is shown that the combination of microtomographic and micromorphological methods is helpful for studying the pore space of compacted horizons in cultivated soils.

Soil compaction monitoring of the Pool Timber Sale, Rio Grande National Forest, Colorado, 16 years after logging

Treesearch

John J. Rawinski; Deborah S. Page-Dumroese

2008-01-01

We conducted a soil monitoring project in 1992 after a shelterwood harvest. One year after harvesting, we determined that 21.32 percent of the area in Unit 5 of the Pool Timber Sale was considered to have detrimental soil compaction. In 2007, we conducted another monitoring project on the same stand by the same person to determine the degree of soil compaction recovery...

Mapping the spatial patterns of field traffic and traffic intensity to predict soil compaction risks at the field scale

NASA Astrophysics Data System (ADS)

Duttmann, Rainer; Kuhwald, Michael; Nolde, Michael

2015-04-01

Soil compaction is one of the main threats to cropland soils in present days. In contrast to easily visible phenomena of soil degradation, soil compaction, however, is obscured by other signals such as reduced crop yield, delayed crop growth, and the ponding of water, which makes it difficult to recognize and locate areas impacted by soil compaction directly. Although it is known that trafficking intensity is a key factor for soil compaction, until today only modest work has been concerned with the mapping of the spatially distributed patterns of field traffic and with the visual representation of the loads and pressures applied by farm traffic within single fields. A promising method for for spatial detection and mapping of soil compaction risks of individual fields is to process dGPS data, collected from vehicle-mounted GPS receivers and to compare the soil stress induced by farm machinery to the load bearing capacity derived from given soil map data. The application of position-based machinery data enables the mapping of vehicle movements over time as well as the assessment of trafficking intensity. It also facilitates the calculation of the trafficked area and the modeling of the loads and pressures applied to soil by individual vehicles. This paper focuses on the modeling and mapping of the spatial patterns of traffic intensity in silage maize fields during harvest, considering the spatio-temporal changes in wheel load and ground contact pressure along the loading sections. In addition to scenarios calculated for varying mechanical soil strengths, an example for visualizing the three-dimensional stress propagation inside the soil will be given, using the Visualization Toolkit (VTK) to construct 2D or 3D maps supporting to decision making due to sustainable field traffic management.

The estimation of parameter compaction values for pavement subgrade stabilized with lime

NASA Astrophysics Data System (ADS)

Lubis, A. S.; Muis, Z. A.; Simbolon, C. A.

2018-02-01

The type of soil material, field control, maintenance and availability of funds are several factors that must be considered in compaction of the pavement subgrade. In determining the compaction parameters in laboratory desperately requires considerable materials, time and funds, and reliable laboratory operators. If the result of soil classification values can be used to estimate the compaction parameters of a subgrade material, so it would save time, energy, materials and cost on the execution of this work. This is also a clarification (cross check) of the work that has been done by technicians in the laboratory. The study aims to estimate the compaction parameter values ie. maximum dry unit weight (γdmax) and optimum water content (Wopt) of the soil subgrade that stabilized with lime. The tests that conducted in the laboratory of soil mechanics were to determine the index properties (Fines and Liquid Limit/LL) and Standard Compaction Test. Soil samples that have Plasticity Index (PI) > 10% were made with additional 3% lime for 30 samples. By using the Goswami equation, the compaction parameter values can be estimated by equation γd max # = -0,1686 Log G + 1,8434 and Wopt # = 2,9178 log G + 17,086. From the validation calculation, there was a significant positive correlation between the compaction parameter values laboratory and the compaction parameter values estimated, with a 95% confidence interval as a strong relationship.

COMPACT: The role of soil management in mitigating catchment flood risk

NASA Astrophysics Data System (ADS)

Pattison, Ian; Coates, Victoria; Frost, Matthew; Demirci, Emrah

2017-04-01

This paper reports a new NERC funded research project which addresses the impact of agricultural soil compaction on surface runoff and catchment scale flood risk. The intensification of agriculture, through increasing the number of animals in pasture, and the use of larger, heavier machinery for arable farming, over the past 50 years or so is hypothesised to have had an impact on the severity and frequency of flooding. These land management practices cause soil compaction, which reduces the rate of rainfall infiltration and the volume of water that can be stored within the sub-surface. This results in more rainfall being partitioned into the faster surface runoff pathway into rivers and potentially causing flooding downstream. However, the level of soil compaction is highly heterogeneous over space and time. This is because different animals i.e. cattle, sheep and horses, exert different loads on the soil and are kept at different densities. Furthermore, farm animals are known to exhibit behaviour whereby certain parts of the field are moved over more frequently than others. The same is the case in arable farming practices, whereby ploughing forms tramlines or wheelings, which are more compacted. Different forms of management practice ranging from zero-tillage to conventional cultivation exert different pressures on the soil at different times of year. However, very little is known about this variability of soil compaction levels at the sub-field level and land under different management practices. This research aims to quantify this sub-field variation in compaction severity and depths through using novel Ground Penetrating Radar (GPR) and Animal tracking GPS technology. Combining these with more conventional soil property tests, including bulk density, saturated hydraulic conductivity and using a penetrometer will allow relationships with frequency of load to be developed over different spatial and temporal scales. Furthermore, X-Ray CT scanning will reveal the fine scale impacts of compaction on soil structure. This data will form the input to a physically based, reduced complexity, spatially distributed hydrological model to test feasible "what if?" scenarios. This will upscale local changes in land management and soil characteristics to catchment scale flooding. Results from research focussing on a priori compacted areas, such as feeding areas, field gates, shelter zones and tractor wheelings show that these are statistically different to areas assumed to be less compacted in the open field.

Real-time measurement of quality during the compaction of subgrade soils.

DOT National Transportation Integrated Search

2012-12-01

Conventional quality control of subgrade soils during their compaction is usually performed by monitoring moisture content and dry density at a few discrete locations. However, randomly selected points do not adequately represent the entire compacted...

Migration of inorganic ions from the leachate of the Rio das Ostras landfill: a comparison of three different configurations of protective barriers.

PubMed

Lacerda, Cláudia Virgínia; Ritter, Elisabeth; Pires, João Antônio da Costa; de Castro, José Adilson

2014-11-01

Batch tests and diffusion tests were performed to analyze the efficiency of a protective barrier in a landfill consisting of compacted soil with 10% bentonite compared to the results obtained for only compacted soil and for compacted soil covered with a 1-mm-thick HDPE geomembrane; the soil and leachate were collected from the Rio das Ostras Landfill in Rio de Janeiro, Brazil. The diffusion tests were performed for periods of 3, 10 and 60 days. After the test period, the soil pore water was analyzed and the profiles for chloride, potassium and ammonium were determined along a 6-cm soil depth. The results of the batch tests performed to define sorption parameters were used to adjust the profiles obtained in the diffusion cell experiment by applying an ion transfer model between the interstitial solution and the soil particles. The MPHMTP model (Multi Phase Heat and Mass Transfer Program), which is based upon the solution of the transport equations of the ionic contaminants, was used to solve the inverse problem of simultaneously determining the effective diffusion coefficients. The results of the experimental tests and of the model simulation confirmed that the compacted soil with 10% bentonite was moderately efficient in the retention of chloride, potassium and ammonium ions compared to the configurations of compacted soil with a geomembrane and compacted soil alone, representing a solution that is technically feasible and requires potentially lower costs for implementation in landfills. Copyright © 2014 Elsevier Ltd. All rights reserved.

Risk assessment of soil compaction in Walloon Region (Belgium)

NASA Astrophysics Data System (ADS)

Charlotte, Rosiere; Marie-France, Destain; Jean-Claude, Verbrugge

2010-05-01

The proposed Soil Framework Directive COM(2006)232 requires Member States to identify areas at risk of erosion, decline in organic matter, salinisation, compaction, sealing and landslides, as well as to set up an inventory of contaminated sites. The present project aims to identify the susceptibility to compaction of soils of the Walloon Region (Belgium) and to recommend good farming practices avoiding soil compaction as far as possible. Within this scope, the concept of precompression stress (Pc) (Horn and Fleige, 2003) was used. Pc is defined as the maximum major principal stress that a soil horizon can withstand against any applied external vertical stress. If applied stress is higher than Pc, the soil enters in a plastic state, not easily reversible. For a given soil, the intensity of soil compaction is mainly due to the applied load which depends on vehicle characteristics (axle load, tyre dimensions, tyre inflation pressure, and vehicle velocity). To determine soil precompression stress, pedotransfert functions of Lebert and Horn (1991) defined at two water suctions (pF 1.8 and 2.5) were used. Parameters required by these functions were found within several databases (Aardewerk and Digital Map of Walloon Soils) and literature. The validation of Pc was performed by measuring stress-strain relationships using automatic oedometers. Stresses of 15.6, 31, 3, 62.5, 125, 250, 500 and 1000 kPa were applied for 10 min each. In this study, the compaction due to beet harvesters was considered because the axle load can exceed 10 tons and these machines are often used during wet conditions. The compaction at two depth levels was considered: 30 and 50 cm. Compaction of topsoil was not taken into account because, under conventional tillage, the plough depth is lower than 25 cm. Before and after the passage of the machines, following measurements were performed: granulometry, density, soil moisture, pF curve, Atterberg limits, ... The software Soilflex (Keller et al., 2007) was used to estimate the distribution of the vertical stresses z in the soil. Comparison was performed between z and Pc. The following data simulated the passage of a beet harvester machine (mass: 23 580 kg; load: 18 000 kg) in a silty soil located in Hesbaye and classified as Aba (Sirjacobs et al., 2000). The passage of the machine would create a Pc of around 100 kPa at 30 cm depth, while the stress induced by the machine would reach 240 kPa. In the field borders, where more vehicle traffic was usually observed and where the soil was over consolidated, Pc would reach 180 kPa, while z would be 220 kPa. In both cases, the risk of compaction created by the passage of the machine would be high. - Lebert, M. and Horn, R. (1991). A method to predict the mechanical strength of agricultural soils. Soil & Tillage Res. 19, 275-286. - Keller T., Défossez P., Weisskopf P., Arvidson J., Richard G. (2007). SoilFlex : A model for prediction of soil stresses and soil compaction due to agricultural field traffic including a synthesis of analytical approaches. Soil & Tillage Research 93, 391-411. - Sirjacobs D., Hanquet B., Lebeau F., Destain M.-F. (2002). On-line mechanical resistance mapping and correlation with soil physical properties for precision agriculture. Soil and Tillage Research, 64, 231-242.

Relationships between Soil compaction and harvest season, soil texture, and landscape position for aspen forests

Treesearch

Randy Kolka; Aaron Steber; Ken Brooks; Charles H. Perry; Matt Powers

2012-01-01

Although a number of harvesting studies have assessed compaction, no study has considered the interacting relationships of harvest season, soil texture, and landscape position on soil bulk density and surface soil strength for harvests in the western Lake States. In 2005, we measured bulk density and surface soil strength in recent clearcuts of predominantly aspen...

Soil physical property changes at the North American long-term soil productivity study sites: 1 and 5 years after compaction

Treesearch

Deborah S. Page-Dumroese; Martin F. Jurgensen; Allan E. Tiarks; Felix Ponder; Felipe G. Sanchez; Robert L. Fleming; J. Marty Kranabetter; Robert F. Powers; Douglas M. Stone; John D. Elioff; D. Andrew Scott

2006-01-01

The impact of forest management operations on soil physical properties is important to understand, since management can significantly change site productivity by altering root growth potential, water infiltration and soil erosion, and water and nutrient availability. We studied soil bulk density and strength changes as indicators of soil compaction before harvesting...

Deep Compaction Control of Sandy Soils

NASA Astrophysics Data System (ADS)

Bałachowski, Lech; Kurek, Norbert

2015-02-01

Vibroflotation, vibratory compaction, micro-blasting or heavy tamping are typical improvement methods for the cohesionless deposits of high thickness. The complex mechanism of deep soil compaction is related to void ratio decrease with grain rearrangements, lateral stress increase, prestressing effect of certain number of load cycles, water pressure dissipation, aging and other effects. Calibration chamber based interpretation of CPTU/DMT can be used to take into account vertical and horizontal stress and void ratio effects. Some examples of interpretation of soundings in pre-treated and compacted sands are given. Some acceptance criteria for compaction control are discussed. The improvement factors are analysed including the normalised approach based on the soil behaviour type index.

The long-term effects of silvicultural thinning and partial cutting on soil compaction in red pine (Pinus resinosa Ait.) and northern hardwood stands in the northern Great Lakes Region of the United States

Treesearch

Rachel A. Tarpey; Martin F. Jurgensen; Brian J. Palik; Randy K. Kolka

2008-01-01

Periodic silvicultural thinnings (23.0, 27.6, 32.1 m2 ha-1 residual basal area) in a red pine stand growing on a sandy soil in north-central Minnesota over a 57-yr period increased soil compaction as the intensity of the thinning treatment increased. Of the three different methods used to measure soil compaction (bulk...

Productivity of planted shortleaf pine in artificially compacted Clarksville soil

Treesearch

Felix Jr. Ponder

2007-01-01

After 9 years, tree survival was 72, 65, and 70 percent for not compacted, medium compacted, and severely compacted treatments, respectively, for shortleaf pine (Pinus echinata Mill.) planted in a forest clearcut on the Carr Creek State Forest in Shannon County, Missouri. The study is in one of the USDA Forest Service's Long-term Soil...

Ten-year results from the long-term soil productivity study in aspen ecosystems of the northern Great Lakes region

Treesearch

Richard Voldseth; Brian J. Palik; John Elioff

2011-01-01

Impacts of organic matter removal and compaction on soil properties and productivity are reported from the first 10 years of the Long-Term Soil Productivity Study in Great Lakes aspen ecosystems. Organic matter removal treatments included main bole, total tree harvest, and total tree harvest with forest floor removal. Compaction treatments included minimal compaction,...

Inter- and Intra- Field variations in soil compaction levels and subsequent impacts on hydrological extremes

NASA Astrophysics Data System (ADS)

Pattison, Ian; Coates, Victoria

2015-04-01

The rural landscape in the UK is dominated by pastoral agriculture, with about 40% of land cover classified as either improved or semi-natural grassland according to the Land Cover Map 2007. Intensification has resulted in greater levels of compaction associated with higher stocking densities. However, there is likely to be a great amount of variability in compaction levels within and between fields due to multiple controlling factors. This research focusses in on two of these factors; firstly animal species, namely sheep, cattle and horses; and secondly field zonation e.g. feeding areas, field gates, open field. Field experiments have been conducted in multiple fields in the River Skell catchment, in Yorkshire, UK, which has an area of 140km2. The effect on physical and hydrologic soil characteristics such as bulk density and moisture contents have been quantified using a wide range of field and laboratory based experiments. Results have highlighted statistically different properties between heavily compacted areas where animals congregate and less-trampled open areas. Furthermore, soil compaction has been hypothesised to contribute to increased flood risk at larger spatial scales. Previous research (Pattison, 2011) on a ~40km2 catchment (Dacre Beck, Lake District, UK) has shown that when soil characteristics are homogeneously parameterised in a hydrological model, downstream peak discharges can be 65% higher for a heavy compacted soil than for a lightly compacted soil. Here we report results from spatially distributed hydrological modelling using soil parameters gained from the field experimentation. Results highlight the importance of both the percentage of the catchment which is heavily compacted and also the spatial distribution of these fields.

Soil response to skidder and dozer traffic as indicated by soil stress residuals

Treesearch

Brian Parkhurst; Mike Aust; Chad Bolding; Scott Barrett; Andrew Vinson; John Klepac; Emily Carter

2015-01-01

Ground-based timber harvesting systems are common throughout many regions of the United States. Machine movements during harvesting can negatively impact soils leading to increased erosion and soil compaction. This is especially true of skid trails that have been established to facilitate tree removals. Several techniques have the potential to reduce soil compaction...

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.

Real-time measurement of soil stiffness during static compaction.

DOT National Transportation Integrated Search

2009-01-01

Is continuous sensing of soil properties during static pad foot roller compaction achievable? A new pad-based, rollerintegrated system for real-time measurement of the elastic modulus of fine- and mixed-grain soils is the goal of Development of So...

Changes in soil physical and chemical properties following organic matter removal and compaction: 20-year response of the aspen Lake-States Long Term Soil Productivity installations

Treesearch

Robert A. Slesak; Brian J. Palik; Anthony W. D' Amato; Valerie J. Kurth

2017-01-01

Soil functions that control plant resource availability can be altered by management activities such as increased organic matter (OM) removal and soil compaction during forest harvesting. The Long Term Soil Productivity study was established to evaluate how these practices influence soil and site productivity using experimental treatments that span a range of forest...

Microbial community responses in forest mineral soil to compaction, organic matter removal, and vegetation control

Treesearch

Matt D. Busse; Samual E. Beattie; Robert F. Powers; Felipe G. Sanchez; Allan E. Tiarks

2006-01-01

We tested three disturbance hypotheses in young conifer plantations: H1: soil compaction and removal of surface organic matter produces sustained changes in microbial community size, activity, and structure in mineral soil; H2: microbial community characteristics in mineral soil are linked to the recovery of plant diversity...

Biochars impact on water infiltration and water quality through a compacted subsoil layer

USDA-ARS?s Scientific Manuscript database

Soils in the Southeastern United States Coastal Plain region frequently have a compacted subsoil layer, which is a barrier for water movement. Four different biochars were evaluated to increase water movement through a compacted horizon from a Norfolk soil (fine-loamy, kaolinitic, thermic, Typic Ka...

Biochar impact on water infiltration and water quality through a compacted subsoil layer

EPA Science Inventory

Soils in the SE USA Coastal Plain region frequently have a compacted subsoil layer (E horizon), which is a barrier for water infiltration. Four different biochars were evaluated to increase water infiltration through a compacted horizon from a Norfolk soil (fine-loamy, kaolinitic...

Influence of wood-derived biochar on the compactibility and strength of silt loam soil

NASA Astrophysics Data System (ADS)

Ahmed, Ahmed; Gariepy, Yvan; Raghavan, Vijaya

2017-04-01

Biochar is proven to enhance soil fertility and increase crop productivity. Given that the influence of biochar on soil compaction remains unclear, selected physico-mechanical properties of soil amended with wood-derived biochar were assessed. For unamended silt loam, the bulk density, maximum bulk density, optimum moisture content, plastic limit, liquid limit, and plasticity index were 1.05 Mg m-3, 1.69 Mg m-3, 16.55, 17.1, 29.3, and 12.2%, respectively. The penetration resistance and shear strength of the unamended silt loam compacted in the standard compaction Proctor mold and at its optimum moisture content were 1800 kPa and 850 kPa, respectively. Results from amending the silt loam with 10% particle size ranges (0.5-212 μm) led to relative decreases of 18.1, 17.75, 66.66, and 97.4% in bulk density, maximum bulk density, penetration resistance, and shear strength, respectively; a 26.8% relative increase in optimum moisture content; along with absolute increases in plastic limit, liquid limit, and plasticity index of 5.3, 13.7, and 8.4%, respectively. While the biochar-amended silt loam soil was more susceptible to compaction, however, soil mechanical impedance enhanced.

The lasting effects of tank maneuvers on desert soils and intershrub flora

USGS Publications Warehouse

Prose, Douglas V.; Wilshire, Howard G.

2000-01-01

Mojave Desert soils and intershrub flora sustained lasting disturbances during military training maneuvers initiated by General George Patton, Jr. in the 1940s, and during Operation Desert Strike in 1964. At six sites, mean desert pavement clast size was significantly smaller by 15% to 50% in single tank tracks compared to undisturbed surfaces. The finer-grained tracks yielded significantly higher surface reflectance values at two of three sites. At one site, Patton era tank tracks cross centuries-old "intaglios" and there was no significant difference in clast size between the disturbances. Full recovery of pavement surfaces may require a change in climate since pavements formed in Pleistocene times under climatic conditions that no longer exist. Tank tracks of both ages exhibited significant levels of soil compaction, as indicated by penetrometer resistance values that were 51% to 120% greater than those in undisturbed soils to 0.3 m depth. Soil bulk density in tracks was 4% to 6% higher than in undisturbed soils. Soil compaction lowered infiltration rates in tank tracks by 24% to 55% in comparison to undisturbed soils. Compaction has prevented the intershrub flora from recovering in tank tracks. Annual and herbaceous perennial plant density was higher by 13% to 56% in tank tracks than in undisturbed soils, but compaction has restricted the growth of individual plants. This was reflected in plant cover values, which were 3% to 16% lower in tank tracks than in undisturbed soils. Soil compaction also altered the species composition. Species with long taproots, such as Chaenactis fremontii, were reduced in density and cover in tank tracks, whereas grass species with shallow, fibrous root systems had large density increases in tracks. Another important element of the intershrub flora, cryptobiotic crust, exhibited a low rate of recovery from the impact of tank travel at one site. The cover of the most well-developed component of the crusts, growing on delicate soil pedicels in undisturbed soils, was reduced by 50% in tank tracks because of destruction and compaction of the uppermost soil layers.

Evaluation of potential site for mineral processing plant

NASA Astrophysics Data System (ADS)

Izwan Ishak, Muhamad Noor; Sipaun, Susan Maria; Mustapha, Ismail; Fahmi Engku Chik, Engku Mohd; Abdullah, Nurliyana; Affandi Mahmood, Airwan

2018-01-01

Nuclear moisture-density gauge is a type of instrument for measuring density and moisture of the material in a relatively thin zone beneath a surface of the material by using low activity of neutron and gamma radiation source. Density and moisture content data of the compacted layers are needed to determine the degree of compaction of soils, aggregate, concrete, asphalt or other materials used in civil engineering works. A gamma radiation source is mounted inside gauge housing with the source rod vertically extended to various depth positions. Direct transmission gamma radiation technique is used to obtain the count reading for the number of photons emitted before it is converted into density reading by microprocessor. This paper presents the inspection technique and results for the measurement of soil moisture and density carried out at potential site for mineral processing plant, Malaysian Nuclear Agency. Primarily, the experiment was conducted to ensure the compaction of ground is suitable for the plant construction. From the calculation, the percentages of soil wet density compaction (%WD Compact) are within acceptable limits with respect to the standard compacted wet soil density measured in the laboratory.

Soil ecosystem services in loblolly pine plantations 15 years after harvest, compaction, and vegetation control

Treesearch

D. Andrew Scott; Robert J. Eaton; Julie A. Foote; Benjamin Vierra; Thomas W. Boutton; Gary B. Blank; Kurt Johnsen

2014-01-01

Site productivity has long been identified as the primary ecosystem service to be sustained in timberlands. However, soil C sequestration and ecosystem biodiversity have emerged as critical services provided by managed forest soils that must also be sustained. These ecosystem services were assessed in response to gradients of organic matter removal, soil compaction,...

Interaction of the Bored Sand and Gravel Drain Pile with the Surrounding Compacted Loam Soil and Foundation Raft Taking into Account Rheological Properties of the Loam Soil and Non-Linear Properties of the Drain Pile

NASA Astrophysics Data System (ADS)

Ter-Martirosyan, Z. G.; Ter-Martirosyan, A. Z.; Anzhelo, G. O.; Buslov, A. S.

2018-01-01

The task of the interaction of the sand and gravel drain pile with the surrounding loam soil after its preliminary deep compaction and formation of the composite ground cylinder from the drain pile and surrounding compacted loam soil (cells) is considered in the article. It is seen that the subsidence and carrying capacity of such cell considerably depends on physical and mechanical properties of the compacted drain piles and surrounding loam soil as well as their diameter and intercellular distance. The strain-stress state of the cell is considered not taking into account its component elements, but taking into account linear and elastic-plastic properties of the drain pile and creep flow of the surrounding loam soil. It is stated that depending on these properties the distribution and redistribution of the load on a cell takes place from the foundation raft between the drain pile and surrounding soil. Based on the results of task solving the formulas and charts are given demonstrating the ratio of the load between the drain pile and surrounding loam soil in time.

40 CFR 264.552 - Corrective Action Management Units (CAMU).

Code of Federal Regulations, 2014 CFR

2014-07-01

... (FML), and the lower component must consist of at least a two-foot layer of compacted soil with a... hazardous wastes, and all media (including ground water, surface water, soils, and sediments) and debris... with the compacted soil component; (ii) Alternate requirements. The Regional Administrator may approve...

40 CFR 264.552 - Corrective Action Management Units (CAMU).

Code of Federal Regulations, 2012 CFR

2012-07-01

... (FML), and the lower component must consist of at least a two-foot layer of compacted soil with a... hazardous wastes, and all media (including ground water, surface water, soils, and sediments) and debris... with the compacted soil component; (ii) Alternate requirements. The Regional Administrator may approve...

40 CFR 264.552 - Corrective Action Management Units (CAMU).

Code of Federal Regulations, 2010 CFR

2010-07-01

... (FML), and the lower component must consist of at least a two-foot layer of compacted soil with a... hazardous wastes, and all media (including ground water, surface water, soils, and sediments) and debris... with the compacted soil component; (ii) Alternate requirements. The Regional Administrator may approve...

40 CFR 264.552 - Corrective Action Management Units (CAMU).

Code of Federal Regulations, 2011 CFR

2011-07-01

... (FML), and the lower component must consist of at least a two-foot layer of compacted soil with a... hazardous wastes, and all media (including ground water, surface water, soils, and sediments) and debris... with the compacted soil component; (ii) Alternate requirements. The Regional Administrator may approve...

Developmental morphology of cover crop species exhibit contrasting behaviour to changes in soil bulk density, revealed by X-ray computed tomography

PubMed Central

Burr-Hersey, Jasmine E.; Mooney, Sacha J.; Bengough, A. Glyn; Mairhofer, Stefan

2017-01-01

Plant roots growing through soil typically encounter considerable structural heterogeneity, and local variations in soil dry bulk density. The way the in situ architecture of root systems of different species respond to such heterogeneity is poorly understood due to challenges in visualising roots growing in soil. The objective of this study was to visualise and quantify the impact of abrupt changes in soil bulk density on the roots of three cover crop species with contrasting inherent root morphologies, viz. tillage radish (Raphanus sativus), vetch (Vicia sativa) and black oat (Avena strigosa). The species were grown in soil columns containing a two-layer compaction treatment featuring a 1.2 g cm-3 (uncompacted) zone overlaying a 1.4 g cm-3 (compacted) zone. Three-dimensional visualisations of the root architecture were generated via X-ray computed tomography, and an automated root-segmentation imaging algorithm. Three classes of behaviour were manifest as a result of roots encountering the compacted interface, directly related to the species. For radish, there was switch from a single tap-root to multiple perpendicular roots which penetrated the compacted zone, whilst for vetch primary roots were diverted more horizontally with limited lateral growth at less acute angles. Black oat roots penetrated the compacted zone with no apparent deviation. Smaller root volume, surface area and lateral growth were consistently observed in the compacted zone in comparison to the uncompacted zone across all species. The rapid transition in soil bulk density had a large effect on root morphology that differed greatly between species, with major implications for how these cover crops will modify and interact with soil structure. PMID:28753645

Developmental morphology of cover crop species exhibit contrasting behaviour to changes in soil bulk density, revealed by X-ray computed tomography.

PubMed

Burr-Hersey, Jasmine E; Mooney, Sacha J; Bengough, A Glyn; Mairhofer, Stefan; Ritz, Karl

2017-01-01

Plant roots growing through soil typically encounter considerable structural heterogeneity, and local variations in soil dry bulk density. The way the in situ architecture of root systems of different species respond to such heterogeneity is poorly understood due to challenges in visualising roots growing in soil. The objective of this study was to visualise and quantify the impact of abrupt changes in soil bulk density on the roots of three cover crop species with contrasting inherent root morphologies, viz. tillage radish (Raphanus sativus), vetch (Vicia sativa) and black oat (Avena strigosa). The species were grown in soil columns containing a two-layer compaction treatment featuring a 1.2 g cm-3 (uncompacted) zone overlaying a 1.4 g cm-3 (compacted) zone. Three-dimensional visualisations of the root architecture were generated via X-ray computed tomography, and an automated root-segmentation imaging algorithm. Three classes of behaviour were manifest as a result of roots encountering the compacted interface, directly related to the species. For radish, there was switch from a single tap-root to multiple perpendicular roots which penetrated the compacted zone, whilst for vetch primary roots were diverted more horizontally with limited lateral growth at less acute angles. Black oat roots penetrated the compacted zone with no apparent deviation. Smaller root volume, surface area and lateral growth were consistently observed in the compacted zone in comparison to the uncompacted zone across all species. The rapid transition in soil bulk density had a large effect on root morphology that differed greatly between species, with major implications for how these cover crops will modify and interact with soil structure.

Sustainable landscaping practices for enhancing vegetation establishment.

DOT National Transportation Integrated Search

2016-02-01

Soil compaction can severely limit the success of vegetation establishment. Current grading and landscaping : practices commonly produce compacted soils of varied textures and profiles within SHA medians and roadsides, : resulting in limited capacity...

Construction procedures using self hardening fly ash

NASA Astrophysics Data System (ADS)

Thornton, S. I.; Parker, D. G.

1980-07-01

Fly ash produced in Arkansas from burning Wyoming low sulfur coal is self-hardening and can be effective as a soil stabilizing agent for clays and sands. The strength of soil-self hardening fly ash develops rapidly when compacted immediately after mixing. Seven day unconfined compressive strengths up to 1800 psi were obtained from 20% fly ash and 80% sand mixtures. A time delay between mixing the fly ash with the soil and compaction of the mixture reduced the strength. With two hours delay, over a third of the strength was lost and with four hours delay, the loss was over half. Gypsum and some commercial concrete retarders were effective in reducing the detrimental effect of delayed compaction. Adequate mixing of the soil and fly ash and rapid compaction of the mixtures were found to be important parameters in field construction of stabilized bases.

Effect of soil compaction and organic matter removal on two earthworm populations and some soil properties in a hardwood forest

Treesearch

D. Jordan; V. C. Hubbard; F., Jr. Ponder; E. C. Berry

1999-01-01

Earthworms can alter the physical, chemical, and biological properties of a forest ecosystem. Any physical manipulation to the soil ecosystem may, in turn, affect the activities and ecology of earthworms. The effects of organic matter removal (logs and forest floor) and soil compaction on earthworm activities were measured in a central hardwood region (oakhickory)...

Precision, accuracy, and efficiency of four tools for measuring soil bulk density or strength.

Treesearch

Richard E. Miller; John Hazard; Steven Howes

2001-01-01

Monitoring soil compaction is time consuming. A desire for speed and lower costs, however, must be balanced with the appropriate precision and accuracy required of the monitoring task. We compared three core samplers and a cone penetrometer for measuring soil compaction after clearcut harvest on a stone-free and a stony soil. Precision (i.e., consistency) of each tool...

Growth response of dominant and co-dominant loblolly pines to organic matter removal, soil compaction, and competition control

Treesearch

Robert Eaton; William Smith; Kim Ludovici

2010-01-01

The Long Term Soil Productivity (LTSP) experiment is a U.S. Forest Service led effort to test the effects that organic matter removal, soil compaction, and competition control have forest soil productivity, as measured by tree growth. A replicated experiment was installed on the Croatan National Forest, NC, in winter 1991 and loblolly pine (Pinus taeda...

Heavy-machinery traffic impacts methane emissions as well as methanogen abundance and community structure in oxic forest soils.

PubMed

Frey, Beat; Niklaus, Pascal A; Kremer, Johann; Lüscher, Peter; Zimmermann, Stephan

2011-09-01

Temperate forest soils are usually efficient sinks for the greenhouse gas methane, at least in the absence of significant amounts of methanogens. We demonstrate here that trafficking with heavy harvesting machines caused a large reduction in CH(4) consumption and even turned well-aerated forest soils into net methane sources. In addition to studying methane fluxes, we investigated the responses of methanogens after trafficking in two different forest sites. Trafficking generated wheel tracks with different impact (low, moderate, severe, and unaffected). We found that machine passes decreased the soils' macropore space and lowered hydraulic conductivities in wheel tracks. Severely compacted soils yielded high methanogenic abundance, as demonstrated by quantitative PCR analyses of methyl coenzyme M reductase (mcrA) genes, whereas these sequences were undetectable in unaffected soils. Even after a year after traffic compression, methanogen abundance in compacted soils did not decline, indicating a stability of methanogens here over time. Compacted wheel tracks exhibited a relatively constant community structure, since we found several persisting mcrA sequence types continuously present at all sampling times. Phylogenetic analysis revealed a rather large methanogen diversity in the compacted soil, and most mcrA gene sequences were mostly similar to known sequences from wetlands. The majority of mcrA gene sequences belonged either to the order Methanosarcinales or Methanomicrobiales, whereas both sites were dominated by members of the families Methanomicrobiaceae Fencluster, with similar sequences obtained from peatland environments. The results show that compacting wet forest soils by heavy machinery causes increases in methane production and release.

Soil properties and aspen development five years after compaction and forest floor removal

Treesearch

Douglas M. Stone; John D. Elioff

1998-01-01

Forest management activities that decrease soil porosity and remove organic matter have been associated with declines in site productivity. In the northern Lake States region, research is in progress in the aspen (Populus tremuloides Michx. and P. grandidentata Michx.) forest type to determine effects of soil compaction and organic...

Influence of nano-material on the expansive and shrinkage soil behavior

NASA Astrophysics Data System (ADS)

Taha, Mohd Raihan; Taha, Omer Muhie Eldeen

2012-10-01

This paper presents an experimental study performed on four types of soils mixed with three types of nano-material of different percentages. The expansion and shrinkage tests were conducted to investigate the effect of three type of nano-materials (nano-clay, nano-alumina, and nano-copper) additive on repressing strains in compacted residual soil mixed with different ratios of bentonite (S1 = 0 % bentonite, S2 = 5 % bentonite, S3 = 10 % bentonite, and S4 = 20 % bentonite). The soil specimens were compacted under the condition of maximum dry unit weight and optimum water content ( w opt) using standard compaction test. The physical and mechanical results of the treated samples were determined. The untreated soil values were used as control points for comparison purposes. It was found that with the addition of optimum percentage of nano-material, both the swell strain and shrinkage strain reduced. The results show that nano-material decreases the development of desiccation cracks on the surface of compacted samples without decrease in the hydraulic conductivity.

40 CFR 258.40 - Design criteria.

Code of Federal Regulations, 2013 CFR

2013-07-01

... component must consist of at least a two-foot layer of compacted soil with a hydraulic conductivity of no... compacted soil com-ponent. (c) When approving a design that complies with paragraph (a)(1) of this section...

40 CFR 258.40 - Design criteria.

Code of Federal Regulations, 2014 CFR

2014-07-01

... component must consist of at least a two-foot layer of compacted soil with a hydraulic conductivity of no... compacted soil com-ponent. (c) When approving a design that complies with paragraph (a)(1) of this section...

40 CFR 258.40 - Design criteria.

Code of Federal Regulations, 2011 CFR

2011-07-01

... component must consist of at least a two-foot layer of compacted soil with a hydraulic conductivity of no... compacted soil com-ponent. (c) When approving a design that complies with paragraph (a)(1) of this section...

40 CFR 258.40 - Design criteria.

Code of Federal Regulations, 2010 CFR

2010-07-01

... component must consist of at least a two-foot layer of compacted soil with a hydraulic conductivity of no... compacted soil com-ponent. (c) When approving a design that complies with paragraph (a)(1) of this section...

40 CFR 258.40 - Design criteria.

Code of Federal Regulations, 2012 CFR

2012-07-01

... component must consist of at least a two-foot layer of compacted soil with a hydraulic conductivity of no... compacted soil com-ponent. (c) When approving a design that complies with paragraph (a)(1) of this section...

Soil compaction: Evaluation of stress transmission and resulting soil structure

NASA Astrophysics Data System (ADS)

Naveed, Muhammad; Schjønning, Per; Keller, Thomas; Lamande, Mathieu

2016-04-01

Accurate estimation of stress transmission and resultant deformation in soil profiles is a prerequisite for the development of predictive models and decision support tools for preventing soil compaction. Numerous studies have been carried out on the effects of soil compaction, whilst relatively few studies have focused on the cause (mode of stress transmission in the soil). We have coupled both cause and effects together in the present study by carrying out partially confined compression tests on (1) wet aggregates, (2) air dry aggregates, and (3) intact soils to quantify stress transmission and compaction-resulted soil structure at the same time. Stress transmission was quantified using both X-ray CT and Tactilus sensor mat, and soil-pore structure was quantified using X-ray CT. Our results imply that stress transmission through soil highly depends on the magnitude of applied load and aggregate strength. As soon as the applied load is lower than the aggregate strength, the mode of stress transmission is discrete as stresses were mainly transmitted through chain of aggregates. With increasing applied load soil aggregates start deforming that transformed heterogeneous soil into homogenous, as a result stress transmission mode was shifted from discrete towards more like a continuum. Continuum-like stress transmission mode was better simulated with Boussinesq (1885) model based on theory of elasticity compared to discrete. The soil-pore structure was greatly affected by increasing applied stresses. Total porosity was reduced 5-16% and macroporosity 50-85% at 620 kPa applied stress for the intact soils. Similarly, significant changes in the morphological indices of the macropore space were also observed with increasing applied stresses.

Load and inflation pressure effects on soil compaction of forwarder tires

Treesearch

Tim McDonald; Tom Way; Bjorn Lofgren; Fernando Seixas; Mats Landstrom

1996-01-01

A standard forwarder tire (600/55-26.5) was tested to determine its range of soil compaction with various inflation pressures and dynamic loads. Past research has shown that compaction of heavier equipment can be somewhat mitigated by operating with lower inflation pressures. Results indicated a significant effect of both load and inflation pressure on bulk density,...

Microbial biomass and bacterial functional diversity in forest soils: effects of organic matter removal, compaction, and vegetation control

Treesearch

Qingchao Li; H. Lee Allen; Arthur G. Wollum

2004-01-01

The effects of organic matter removal, soil compaction, and vegetation control on soil microbial biomass carbon, nitrogen, C-to-N ratio, and functional diversity were examined in a 6-year loblolly pine plantation on a Coastal Plain site in eastern North Carolina, USA. This experimental plantation was established as part of the US Forest Service's Long Term Soil...

Progress report: effects of subsoiling study, Milford Ranger District, Plumas National Forest

Treesearch

John T. Kliejunas; William J. Otrosina

1997-01-01

Subsoiling is becoming a standard practice to alleviate detrimental soil compaction following biomass harvesting in eastside pine and mixed conifer forests in California. Compaction of soil following the harvesting can be detrimental to growth of residuals, to establishment of natural regeneration, and may change long-term soil productivity. The short and long-term...

Estimation of Compaction Parameters Based on Soil Classification

NASA Astrophysics Data System (ADS)

Lubis, A. S.; Muis, Z. A.; Hastuty, I. P.; Siregar, I. M.

2018-02-01

Factors that must be considered in compaction of the soil works were the type of soil material, field control, maintenance and availability of funds. Those problems then raised the idea of how to estimate the density of the soil with a proper implementation system, fast, and economical. This study aims to estimate the compaction parameter i.e. the maximum dry unit weight (γ dmax) and optimum water content (Wopt) based on soil classification. Each of 30 samples were being tested for its properties index and compaction test. All of the data’s from the laboratory test results, were used to estimate the compaction parameter values by using linear regression and Goswami Model. From the research result, the soil types were A4, A-6, and A-7 according to AASHTO and SC, SC-SM, and CL based on USCS. By linear regression, the equation for estimation of the maximum dry unit weight (γdmax *)=1,862-0,005*FINES- 0,003*LL and estimation of the optimum water content (wopt *)=- 0,607+0,362*FINES+0,161*LL. By Goswami Model (with equation Y=mLogG+k), for estimation of the maximum dry unit weight (γdmax *) with m=-0,376 and k=2,482, for estimation of the optimum water content (wopt *) with m=21,265 and k=-32,421. For both of these equations a 95% confidence interval was obtained.

Annually laminated sequences in the internal structure of some Belgian stalagmites -- Importance for paleoclimatology

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

Genty, D.; Quinif, Y.

1996-01-01

Fifteen stalagmites from four caves and one sealed tunnel in southern Belgium are composed of alternations of annually deposited white-porous and dark-compact laminae. This is demonstrated by comparing the number of laminae with the local history of the site for modern stalagmites and with radioisotopic ages for Late Glacial and Holocene stalagmites. Annual cyclicity in the internal structure of these speleothems is explained by the highly seasonal variations of the water excess, which influences underground water flow. Comparison between climatic data and modern stalagmites of a closed tunnel shows that growth laminae can record climatic variations: (1) there is amore » good correlation (R = 0.84) between lamina thickness in a stalagmite and water excess; (2) during years with a high water excess, dark-compact laminae are more developed, which makes the speleothem darker. Vertical successions of several laminae represent microsequences that may have recorded climatic variations with a time resolution of 1/2 year. In a Late Glacial stalagmite, successive laminae microsequences form very regular cycles of 11 years separated by a thick dark-compact lamina. It is supported that, as for modern stalagmites, the thick dark-compact lamina corresponds to a period of high water excess. Hence, this 11-year cycle may reflect a climatic cycle.« less

Effects of organic matter removal and soil compaction on fifth-year mineral soil carbon and nitrogen contents for sites across the United States and Canada

Treesearch

Felipe G. Sanchez; Allan E. Tiarks; J. Marty Kranabetter; Deborah S. Page-Dumroese; Robert F. Powers; Paul T. Sanborn; William K. Chapman

2006-01-01

This study describes the main treatment effects of organic matter removal and compaction and a split-plot effect of competition control on mineral soil carbon (C) and nitrogen (N) pools. Treatment effects on soil C and N pools are discussed for 19 sites across five locations (British Columbia, Northern Rocky Mountains, Pacific Southwest, and Atlantic and Gulf coasts)...

Effects of Tillage Practices on Soil Organic Carbon and Soil Respiration

NASA Astrophysics Data System (ADS)

Rusu, Teodor; Ioana Moraru, Paula; Bogdan, Ileana; Ioan Pop, Adrian

2016-04-01

Soil tillage system and its intensity modify by direct and indirect action soil temperature, moisture, bulk density, porosity, penetration resistance and soil structural condition. Minimum tillage and no-tillage application reduce or completely eliminate the soil mobilization, due to this, soil is compacted in the first years of application. The degree of compaction is directly related to soil type and its state of degradation. All this physicochemical changes affect soil biology and soil respiration. Soil respiration leads to CO2 emissions from soil to the atmosphere, in significant amounts for the global carbon cycle. Soil respiration is one measure of biological activity and decomposition. Soil capacity to produce CO2 varies depending on soil, season, intensity and quality of agrotechnical tillage, soil water, cultivated plant and fertilizer. Our research follows the effects of the three tillage systems: conventional system, minimum tillage and no-tillage on soil respiration and finally on soil organic carbon on rotation soybean - wheat - maize, obtained on an Argic Faeoziom from the Somes Plateau, Romania. To quantify the change in soil respiration under different tillage practices, determinations were made for each crop in four vegetative stages (spring, 5-6 leaves, bean forming, harvest). Soil monitoring system of CO2 and O2 included gradient method, made by using a new generation of sensors capable of measuring CO2 concentration in-situ and quasi-instantaneous in gaseous phase. At surface soil respiration is made by using ACE Automated Soil CO2 Exchange System. These areas were was our research presents a medium multi annual temperature of 8.20C medium of multi annual rain drowns: 613 mm. The experimental variants chosen were: i). Conventional system: reversible plough (22-25 cm) + rotary grape (8-10 cm); ii). Minimum tillage system: paraplow (18-22 cm) + rotary grape (8-10 cm); iii). No-tillage. The experimental design was a split-plot design with three replications. In one variant the area of a plot was 300 m2. Soil respiration varies throughout the year for all three crops of rotation, with a maximum in late spring (1383 to 2480 mmoli m-2s-1) and another in fall (2141 to 2350 mmoli m-2s-1). The determinations confirm the effect of soil tillage system on soil respiration; the daily average is lower at no-tillage (315-1914 mmoli m-2s-1), followed by minimum tillage (318-2395 mmoli m-2s-1) and is higher in the conventional tillage (321-2480 mmol m-2s-1). An exceeding amount of CO2 produced in the soil and released into the atmosphere, resulting from aerobic processes of mineralization of organic matter (excessive loosening) is considered to be not only a way of increasing the CO2 in the atmosphere, but also a loss of long-term soil fertility. By determining the humus content after 3 years, it can be observed an increasing tendency when applying the minimum tillage (the increase was up to 0.41%) and no-tillage systems tillage (the increase was up to 0.64%). Carbon sequestration in soil is net advantageous, improving the productivity and sustainability. The more the organic content in soil is higher the better soil aggregation is. The soil without organic content is compact. This reduces its capacity to infiltrate water, nutrients solubility and productivity, and that way it reduces the soil capacity for carbon sequestration. Acknowledgments This paper was performed under the frame of the Partnership in priority domains - PNII, developed with the support of MEN-UEFISCDI, project no. PN-II-PT-PCCA-2013-4-0015: Expert System for Risk Monitoring in Agriculture and Adaptation of Conservative Agricultural Technologies to Climate Change.

Biomass removal, soil compaction, and vegetation control effects on five-year growth of Douglas-fir in coastal Washington.

Treesearch

A. Ares; T. Terry; C. Harrington; W. Devine; D. Peter; J. Bailey

2007-01-01

Sustainable forest production requires an understanding of the effects of site disturbance on tree growth and the consequences of soil amelioration and vegetation control practices. We assessed the impacts of biomass removals at harvest, soil compaction and tillage, and vegetation control on early growth of Douglas-fir in coastal Washington. Harvest treatments included...

Construction and performance of rugged ceramic cup soil water samplers

Treesearch

Douglas M. Stone; James L. Robl

1996-01-01

To assess solute concentration changes associated with soil compaction and organic matter removal resulting from forest harvesting, we constructed and field tested ceramic cup soil water samplers designed to withstand the forces of compaction by heavy equipment. They were installed with the cup at either the 30-or 60-cm depth; the vacuum and collection tubes rested on...

Aspen development on similar soils in Minnesota and British Columbia after compaction and forest floor removal

Treesearch

Douglas M. Stone; Richard Kabzems

2002-01-01

Forest management practices that decrease soil porosity and remove organic matter can reduce site productivity. We evaluated effects of four treatments-merchantable bole harvest (MBH) with three levels of soil compaction (none, light, or heavy), and total woody vegetation harvest plus forest floor removal (FFR)-on fifth-year regeneration and growth of aspen (...

Fabrication methods for low impedance lithium polymer electrodes

DOEpatents

Chern, T.S.; MacFadden, K.O.; Johnson, S.L.

1997-12-16

A process is described for fabricating an electrolyte-electrode composite suitable for high energy alkali metal battery that includes mixing composite electrode materials with excess liquid, such as ethylene carbonate or propylene carbonate, to produce an initial formulation, and forming a shaped electrode therefrom. The excess liquid is then removed from the electrode to compact the electrode composite which can be further compacted by compression. The resulting electrode exhibits at least a 75% lower resistance.

Fabrication methods for low impedance lithium polymer electrodes

DOEpatents

Chern, Terry Song-Hsing; MacFadden, Kenneth Orville; Johnson, Steven Lloyd

1997-01-01

A process for fabricating an electrolyte-electrode composite suitable for high energy alkali metal battery that includes mixing composite electrode materials with excess liquid, such as ethylene carbonate or propylene carbonate, to produce an initial formulation, and forming a shaped electrode therefrom. The excess liquid is then removed from the electrode to compact the electrode composite which can be further compacted by compression. The resulting electrode exhibits at least a 75% lower resistance.

Moisture-strength-constructability guidelines for subgrade foundation soils found in Indiana.

DOT National Transportation Integrated Search

2016-09-01

Soil moisture is an important indicator of constructability in the field. Construction activities become difficult when the soil moisture content is excessive, especially in fine-grained soils. Change orders caused by excessive soil moisture during c...

Agricultural machineries wheeling and soil qualities mapping in climatic changes conditions

NASA Astrophysics Data System (ADS)

Bergonzoli, S.; Servadio, P.

2012-04-01

As argued in the Fourth Assessment Report of the UN International Panel on Climate Change (IPCC) published in 2007 the global climate is changing and will continue to change in the near future. Due to the changing in time distribution and intensity of rainfall, the available time to carry out soil tillage operations, seedbed preparation and fertilizers distribution is becoming shorter. These issues are worsened by soil compaction that is one of the major problems facing modern agriculture. Soil compaction impedes infiltration of rainfall, so the increasing scale of mechanization might well be responsible for greater runoff, soil loss by water erosion and water-logging. Overuse of machinery, intensive cropping, short crop rotations, intensive grazing and inappropriate soil management leads to compaction. The objective of this research was to study the compacting effect of two wheeled tractors fitted with different type of tires during fertilizing operations with soil water content over field capacity. Field tests were carried out in a farm near Rome (41°52'502'' Latitude (N); 12°12'866" Longitude (E)) in March 2010 on a clay soil (Vertic Cambisol) during wheat fertilizing. One tractor was fitted with very narrow and high aspect ratio tires with mounted broadcaster coded (WTN), the other tractor was equipped with extra large and low aspect ratio tires with trailed broadcaster for a total of four axles coded (WTEL). Immediately after fertilising operations, such effects have been quantified through spatial variation of some soil parameters: soil water content, soil penetration resistance (CI) and soil shear strength (SS). Soil samplings have been carried out on the tracks left by the tractors and on soil not interested by the passage (control). To monitor all tractors passes across the field and to compute the total area covered by tractors tires a DGPS receiver was placed into the tractors; to map soil parameters studied, both on tracks left by the tractors passes and on control areas, a software GIS was used. Results shown the highest level of soil compaction caused by the traffic of WTN in term of CI and SS. In fact, increment ratio respect to the control measured after the tractors pass were: CI = 0.65 and 0.14 for WTN and for WTEL respectively; SS = 0.65 and 0.46 for WTN and WTEL respectively. Comparing the two different tires, significant differences were found particularly in the surface layers (0-0.20 m depth): mean values of CI and SS were higher for WTN (0.47 and 1.60 respectively) respect to WTEL. Track area covered by the two treatments respect to the whole field (16.32 ha) were: 0.025 for treatment WTN (0.27 m tires width) having an operative work width of 24 m ; 0.075 for treatment WTEL (0.85 m tires width) having an operative work width of 14 m. Results of this study highlighted that, in these field conditions (clay soil, water content over field capacity), tractor pass with very narrow tires caused a soil compaction level too high up to be impossible to traffic into the field. To operate at these soil water content conditions a tractors fitted with low aspect ratio and low inflation pressure tires is necessary. With lower soil water content, narrow tires allow carrying out fertilization into the inter-row avoiding crop trampling and compacting less percentage of field area respect to the a tractor equipped with large tires. Key words: Tractor, Soil trafficability, Soil compaction, Tires, GPS, GIS. Acknowledgements This work was carried out under the auspices of the special project "Sceneries of adaptation of the Italian agriculture to the climatic changes" (AGROSCENARI) of the Agricultural Research Council, and Italian Ministry of the Agricultural and Forestry Politics.

How serious a problem is subsoil compaction in the Netherlands? A survey based on probability sampling

NASA Astrophysics Data System (ADS)

Brus, Dick J.; van den Akker, Jan J. H.

2018-02-01

Although soil compaction is widely recognized as a soil threat to soil resources, reliable estimates of the acreage of overcompacted soil and of the level of soil compaction parameters are not available. In the Netherlands data on subsoil compaction were collected at 128 locations selected by stratified random sampling. A map showing the risk of subsoil compaction in five classes was used for stratification. Measurements of bulk density, porosity, clay content and organic matter content were used to compute the relative bulk density and relative porosity, both expressed as a fraction of a threshold value. A subsoil was classified as overcompacted if either the relative bulk density exceeded 1 or the relative porosity was below 1. The sample data were used to estimate the means of the two subsoil compaction parameters and the overcompacted areal fraction. The estimated global means of relative bulk density and relative porosity were 0.946 and 1.090, respectively. The estimated areal fraction of the Netherlands with overcompacted subsoils was 43 %. The estimates per risk map unit showed two groups of map units: a low-risk group (units 1 and 2, covering only 4.6 % of the total area) and a high-risk group (units 3, 4 and 5). The estimated areal fraction of overcompacted subsoil was 0 % in the low-risk unit and 47 % in the high-risk unit. The map contains no information about where overcompacted subsoils occur. This was caused by the poor association of the risk map units 3, 4 and 5 with the subsoil compaction parameters and subsoil overcompaction. This can be explained by the lack of time for recuperation.

Models of compacted fine-grained soils used as mineral liner for solid waste

NASA Astrophysics Data System (ADS)

Sivrikaya, Osman

2008-02-01

To prevent the leakage of pollutant liquids into groundwater and sublayers, the compacted fine-grained soils are commonly utilized as mineral liners or a sealing system constructed under municipal solid waste and other containment hazardous materials. This study presents the correlation equations of the compaction parameters required for construction of a mineral liner system. The determination of the characteristic compaction parameters, maximum dry unit weight ( γ dmax) and optimum water content ( w opt) requires considerable time and great effort. In this study, empirical models are described and examined to find which of the index properties correlate well with the compaction characteristics for estimating γ dmax and w opt of fine-grained soils at the standard compactive effort. The compaction data are correlated with different combinations of gravel content ( G), sand content ( S), fine-grained content (FC = clay + silt), plasticity index ( I p), liquid limit ( w L) and plastic limit ( w P) by performing multilinear regression (MLR) analyses. The obtained correlations with statistical parameters are presented and compared with the previous studies. It is found that the maximum dry unit weight and optimum water content have a considerably good correlation with plastic limit in comparison with liquid limit and plasticity index.

Ten-year results from the North American long-term soil productivity study in the Western Gulf Coastal Plain

Treesearch

D. Andrew Scott; John Novosad; Gala Golddsmith

2007-01-01

Forest management operations have the greatest potential to reduce soil productivity through altered soil fertility and air/water balance, which are most affected by organic matter removal and compaction, respectively. The objectives of this study were to assess the early growth response to compaction, organic matter removal, and weed control on the ten locations of...

Nine-year response of hardwood understory to organic matter removal and soil compaction

Treesearch

Felix Ponder

2008-01-01

The effects of three levels of organic matter removal (OMR) and three levels of soil compaction (SC) on the development of understory vegetation in a central hardwood forest were evaluated 9 years after treatments were applied as part of a national program of long-term soil productivity research. The three levels of biomass removal (OMR) were removal of merchantable...

Establishment and early growth of conifers on compact soils in urban areas

Treesearch

Robert P. Zisa; Howard G. Halverson; Benjamin B. Stout

1979-01-01

A study of pitch pine, Austrian pine, and Norway spruce on two different urban soils compacted to bulk densities of 1.2, 1.3, 1.6, and 1.8 g•cm-3 and maintained at high water potentials showed that all three species could become established from seed at high soil bulk densities. Pitch pine was the most suceessful species in establishment...

Soil management practice in Croatian vineyard affect CO2 fluxes and soil degradation in trafficking zones. First results

NASA Astrophysics Data System (ADS)

Bogunovic, Igor; Bilandzija, Darija; Andabaka, Zeljko; Stupic, Domagoj; Cacic, Marija; Brezinscak, Luka; Maletic, Edi; Pereira, Paulo; Kisic, Ivica

2017-04-01

Vineyards represent one of the most degradation prone types of intensively managed land on Earth. Steep slopes encourage grape producers to adopt environmental friendly soil management like mulching or continuous no-tillage. In this context, producers have concerns about efficient fertilisation practices and water competitions between vine and grasses in continuous no-tillage inter rows. Vineyards in semi-humid areas like Continental Croatia mostly not suffer from water deficit during growth. Nevertheless, lack of research of different soil management practices open dilemma about soil compaction concerns in intensively trafficked soils in vineyard of semi-humid areas. Soil compaction, determined by bulk density (BD), soil water content (SWC) and CO2 fluxes from trafficked inter row positions were recorded in 2016 in an experiment in which four different soil management systems were compared in a vineyard raised on a silty clay loam soil, near Zagreb, Croatia: No-tillage (NT) system, continuous tillage (CT) and yearly inversed grass covered (INV-GC) and tillage managed (INV-T) inter rows are subjected to intensive traffic. Grape yield and must quality of grape variety Chardonnay was also monitored. Tractor traffic increased the soil BD at 0-10 and 10-20 cm, but especially at the 0-10 cm depth. CT treatment record lowest compaction at 0-10 cm because of tillage. Soil water content showed better conservation possibilities of INV-GC in drier period. In wet period SWC possibilities are similar between treatments. The results of soil compaction under different management indicate that vineyard soil differently response to traffic intensity and impact on microfauna activity and CO2 emissions. INV-GC and NT managed soils record lower CO2 fluxes from vineyard soil compared to CT and INV-T treatments. Management treatments did not statistically influenced on grape yields. Several years of investigation is needed to confirm the overall impact of different management treatments on the proportion of degradation process and their response to proportion of tractor circulation impacts.

A New Non-Destructive TDR System Combined with a Piezoelectric Stack for Measuring Properties of Geomaterials

PubMed Central

Choi, Chanyong; Song, Minwoo; Kim, Daehyeon; Yu, Xiong

2016-01-01

Dry density and water content are two important factors affecting the degree of soil compaction. Conventional methods such as the sand cone test and the plate load test are used to measure such properties for evaluating the degree of compaction and the stiffness of soil in the field. However, these tests are generally very time-consuming and are inherent with some errors depending on the operator (in particular for the sand cone test). Elastic modulus is an indicator to describe the stress-strain behavior of soil and in some cases is used as a design input parameter. Although a rod type TDR (Time Domain Reflectometry) system has been recently proposed to overcome some shortcomings of the conventional methods (particularly the sand cone test), it requires driving the probes into the ground, thus implying that it is still a time-consuming and destructive testing method. This study aims to develop a new non-destructive TDR system that can rapidly measure the dry density, water content, and elastic modulus of soil on the surface of compacted soil, without disturbing the ground. In this study, the Piezoelectric Stack, which is an instrument for measuring the elastic modulus of soil, has been added to the TDR system with a flat type probe, leading to a non-destructive TDR system that is capable of measuring the dry density, water content, and elastic modulus of soil. The new TDR system developed is light enough for an engineer to carry. Results of the standard compaction and TDR tests on sand showed that the dry densities and the moisture contents measured with the new TDR system were in good agreement with those measured with the standard compaction test, respectively. Consequently, it appears that the new TDR system developed will be very useful to advance the current practice of compaction quality control. PMID:28773563

A New Non-Destructive TDR System Combined with a Piezoelectric Stack for Measuring Properties of Geomaterials.

PubMed

Choi, Chanyong; Song, Minwoo; Kim, Daehyeon; Yu, Xiong

2016-06-02

Dry density and water content are two important factors affecting the degree of soil compaction. Conventional methods such as the sand cone test and the plate load test are used to measure such properties for evaluating the degree of compaction and the stiffness of soil in the field. However, these tests are generally very time-consuming and are inherent with some errors depending on the operator (in particular for the sand cone test). Elastic modulus is an indicator to describe the stress-strain behavior of soil and in some cases is used as a design input parameter. Although a rod type TDR (Time Domain Reflectometry) system has been recently proposed to overcome some shortcomings of the conventional methods (particularly the sand cone test), it requires driving the probes into the ground, thus implying that it is still a time-consuming and destructive testing method. This study aims to develop a new non-destructive TDR system that can rapidly measure the dry density, water content, and elastic modulus of soil on the surface of compacted soil, without disturbing the ground. In this study, the Piezoelectric Stack, which is an instrument for measuring the elastic modulus of soil, has been added to the TDR system with a flat type probe, leading to a non-destructive TDR system that is capable of measuring the dry density, water content, and elastic modulus of soil. The new TDR system developed is light enough for an engineer to carry. Results of the standard compaction and TDR tests on sand showed that the dry densities and the moisture contents measured with the new TDR system were in good agreement with those measured with the standard compaction test, respectively. Consequently, it appears that the new TDR system developed will be very useful to advance the current practice of compaction quality control.

Implementation of intelligent compaction technologies for road constructions in Wyoming.

DOT National Transportation Integrated Search

2015-03-01

Conventional test methods for roadway compaction cover less than 1% of roadway; whereas, intelligent : compaction (IC) offers a method to measure 100% of a roadway. IC offers the ability to increase : compaction uniformity of soils and asphalt paveme...

Report of the workshop on intelligent compaction for soils and HMA.

DOT National Transportation Integrated Search

2008-04-01

This document summarizes the discussion and findings of a workshop on intelligent compaction for soils and hot-mix asphalt held in West Des Moines, Iowa, on April 2-4, 2008. The objective of the meeting was to provide a collaborative exchange of idea...

THE ARS-MISSOURI SOIL STRENGTH PROFILE SENSOR: CURRENT STATUS AND FUTURE PROSPECTS

USDA-ARS?s Scientific Manuscript database

Soil compaction that is induced by tillage and traction is an ongoing concern in crop production, and also has environmental consequences. Although cone penetrometers provide standardized compaction measurements, the pointwise data collected makes it difficult to obtain enough data to represent with...

Soil compaction effects of forwarding and its relationship with 6- and 8-wheel drive machines

Treesearch

Fernando Seixas; Tim McDonald

1997-01-01

A study was done to determine the impact, if any, of a range of drive train options on the soil compaction effects of forwarders. The purpose of the study was to evaluate the cost of optional forwarder equipment versus its ability to reduce detrimental soil physical property changes. Tests were done on forwarders equipped with wide and narrow tires, rear steel tracks,...

Negligible effects of severe organic matter removal and soil compaction on loblolly pine growth over 10 years

Treesearch

Felipe G. Sanchez; D. Andrew Scott; Kim H. Ludovici

2006-01-01

The long-term soil productivity (LTSP) study was initiated to examine the effect of soil porosity and organic matter (OM) levels on net primary productivity (NPP). The study design calls for three levels of OM removal (bole, whole tree and whole tree plus forest floor) and three levels of compaction (none, moderate and severe) being imposed on harvested sites prior to...

Aboveground biomass responses to organic matter removal, soil compaction, and competing vegetation control on 20-year mixed conifer plantations in California

Treesearch

Jianwei Zhang; Matt D. Busse; David H. Young; Gary O. Fiddler; Joseph W. Sherlock; Jeff D. TenPas

2017-01-01

We measured vegetation growth 5, 10, and 20 years following plantation establishment at 12 Long-term Soil Productivity installations in California’s Sierra Nevada and Southern Cascades. The combined effects of soil compaction (none, moderate, severe), organic matter removal (tree bole only, whole tree, whole tree plus forest floor), and competing vegetation...

Closeup View of Compacted Soil

NASA Technical Reports Server (NTRS)

2004-01-01

Soil on Mars can be a bit clumpy, as shown in this image of soil after it was compacted by one of the wheels of NASA's Mars Exploration Rover Spirit. Scientists think the light-colored material may be a global layer of airfall dust. Spirit's microscopic imager took this picture, showing an area approximately 3 centimeters (1.2 inches) square, during the rover's 314th martian day, or sol (Nov. 19, 2004).

Effects of Soil Compaction and Organic Matter Removal on Morphology of Secondary Roots of Loblolly Pine

Treesearch

Charles H. Walkinshaw; Allan E. Tiarks

1998-01-01

Root studies are being used to monitor possible changes in growth of loblolly pines on a long-term soil productibity study site. Here, we report the results of a preliminary look sat roots in the sizth growing season. Roots were collected from loblly pines gorwn in soil that was first subjected to three levels of compaction )none, moderate, severe) and three levels...

Measurement of the open porosity of agricultural soils with acoustic waves

NASA Astrophysics Data System (ADS)

Luong, Jeanne; Mercatoris, Benoit; Destain, Marie-France

2015-04-01

The space between agricultural soil aggregates is defined as structural porosity. It plays important roles in soil key functions that an agricultural soil performs in the global ecosystem. Porosity is one of the soil properties that affect plant growth along with soil texture, aggregate size, aeration and water holding capacity (Alaoui et al. 2011). Water supplies regulation of agricultural soil is related to the number of very small pores present in a soil due to the effect of capillarity. Change of porosity also affect the evaporation of the water on the surface (Le Maitre et al. 2014). Furthermore, soil is a habitat for soils organisms, and most living organisms, including plant roots and microorganisms require oxygen. These organisms breathe easier in a less compacted soil with a wide range of pores sizes. Soil compaction by agricultural engine degrades soil porosity. At the same time, fragmentation with tillage tools, creation of cracks due to wetting/drying and freezing/thawing cycles and effects of soil fauna can regenerate soil porosity. Soil compaction increases bulk density since soil grains are rearranged decreasing void space and bringing them into closer contact (Hamza & Anderson 2005). Drainage is reduced, erosion is facilitated and crop production decreases in a compacted soil. Determining soil porosity, giving insight on the soil compaction, with the aim to provide advices to farmers in their soil optimization towards crop production, is thus an important challenge. Acoustic wave velocity has been correlated to the porosity and the acoustic attenuation to the water content (Oelze et al. 2002). Recent studies have shown some correlations between the velocity of acoustic waves, the porosity and the stress state of soil samples (Lu et al. 2004; Lu 2005; Lu & Sabatier 2009), concluding that the ultrasonic waves are a promising tool for the rapid characterisation of unsaturated porous soils. Propagation wave velocity tends to decrease in a high porous soil, since there are more voids filled with air and water, increasing the viscous losses. Fellah et al. (2003) showed that porosity can be determined from phase speed and reflection coefficient. The propagation of acoustic waves in soil is investigated to develop a rapid method for the quantification of the porosity level of agricultural soils. In the present contribution, correlations are determined between the acoustic signatures of agricultural soil in function of its structural properties. In laboratory, compression tests are performed on unsaturated soil samples to reproduce different porosity levels. Ultrasonic pulses are sent through the considered samples. The propagated signals are treated in both time and frequency domains in order to determine the speed of the phase velocity and the reflection. Porosity is then determined and compared with water content measured by gravimetric method. Alaoui, A., Lipiec, J. & Gerke, H.H., 2011. A review of the changes in the soil pore system due to soil deformation: A hydrodynamic perspective. Soil and Tillage Research, 115-116, pp.1-15. Fellah Z.E.A., Berger S., Lauriks W., Depollier C., Aristegui C., Chapelon J.Y., 2003. Measuring the porosity and the tortuosity of porous materials via reflected waves at oblique incidence. The Journal of the Acoustical Society of America 113 (5), pp 2424-2433 Hamza, M.A. & Anderson, W.K., 2005. Soil compaction in cropping systems. Soil and Tillage Research, 82(2), pp.121-145. Lu, Z., 2005. Role of hysteresis in propagating acousitcs waves in soils. Geophysical Research Letter, pp.32:1-4. Lu, Z., Hickey, C.J. & Sabatier, J.M., 2004. Effects of compaction on the acoustic velocity in soils. Soil Science Society of America Journal, 68(1), pp.7-16. Lu, Z. & Sabatier, J.M., 2009. Effects of soil water potential and moisture content on sound speed. Soil Science Society of America Journal, 73(5), pp.1614-1625. Le Maitre, D.C., Kotzee, I.M. & O'Farrell, P.J., 2014. Impacts of land-cover change on the water flow regulation ecosystem service: Invasive alien plants, fire and their policy implications. Land Use Policy, 36, pp.171-181. Oelze, M.L., O'Briena, W.D. & Darmody, R.G., 2002. Measurement of attenuation and speed of sound in soils. Soil. Sci. Soc. Am. J.

Influence of Organic Amendment and Compaction on Nutrient Dynamics in a Saturated Saline-Sodic Soil from the Riparian Zone.

PubMed

Miller, J J; Bremer, E; Curtis, T

2016-07-01

Cattle grazing in wet riparian pastures may influence nutrient dynamics due to nutrient deposition in feces and urine, soil compaction, and vegetation loss. We conducted a lab incubation study with a saline-sodic riparian soil to study nutrient (N, P, S, Fe, Mn, Cu, and Zn) dynamics in soil pore water using Plant Root Simulator (PRS) probes and release of nutrients into the overlying ponded water during flooding. The treatment factors were organic amendment (manure, roots, and unamended control), compaction (compacted, uncompacted), and burial time (3, 7, and 14 d). Amendment treatment had the greatest impact on nutrient dynamics, followed by burial time, whereas compaction had little impact. The findings generally supported our hypothesis that organic amendments should first increase nitrate loss, then increase Mn mobility, then Fe mobility and associated release of P, and finally increase sulfate loss. Declines in nitrate due to amendment addition were small because nitrate was at low levels in all treatments due to high denitrification potential instead of being released to soil pore water or overlying water. Addition of organic amendment strongly increased Mn and Fe concentrations in overlying water and of adsorbed Fe on PRS probes but only increased Mn on PRS probes on Day 3 due to subsequent displacement from ion exchange membranes. Transport of P to overlying water was increased by organic amendment addition but less so for manure than roots despite higher P on PRS probes. The findings showed that saline-sodic soils in riparian zones are generally a nutrient source for P and are a nutrient sink for N as measured using PRS probes after 3 to 7 d of flooding. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Report of the workshop on intelligent compaction for soils and HMA : executive summary.

DOT National Transportation Integrated Search

2008-04-01

This document summarizes the discussion and findings of a workshop on intelligent compaction for soils and hot-mix asphalt held in West Des Moines, Iowa, on April 2-4, 2008. The objective of the meeting was to provide a collaborative exchange of idea...

METHOD OF ESTIMATING THE TRAVEL TIME OF NONINTERACTING SOLUTES THROUGH COMPACTED SOIL MATERIAL

EPA Science Inventory

The pollutant travel time through compacted soil material (i.e., when a pollutant introduced at the top first appears at the bottom) cannot be accurately predicted from the permeability (saturated hydraulic conductivity) alone. The travel time is also dependent on the effective p...

Enhanced Cover Assessment Project:Soil Manipulation and Revegetation Tests

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

Waugh, W. Joseph; Albright, Dr. Bill; Benson, Dr. Craig

2014-02-01

The U.S. Department of Energy Office of Legacy Management is evaluating methods to enhance natural changes that are essentially converting conventional disposal cell covers for uranium mill tailings into water balance covers. Conventional covers rely on a layer of compacted clayey soil to limit exhalation of radon gas and percolation of rainwater. Water balance covers rely on a less compacted soil “sponge” to store rainwater, and on soil evaporation and plant transpiration (evapotranspiration) to remove stored water and thereby limit percolation. Over time, natural soil-forming and ecological processes are changing conventional covers by increasing hydraulic conductivity, loosening compaction, and increasingmore » evapotranspiration. The rock armor on conventional covers creates a favorable habitat for vegetation by slowing soil evaporation, increasing soil water storage, and trapping dust and organic matter, thereby providing the water and nutrients needed for plant germination, survival, and sustainable transpiration. Goals and Objectives Our overall goal is to determine if allowing or enhancing these natural changes could improve cover performance and reduce maintenance costs over the long term. This test pad study focuses on cover soil hydrology and ecology. Companion studies are evaluating effects of natural and enhanced changes in covers on radon attenuation, erosion, and biointrusion. We constructed a test cover at the Grand Junction disposal site to evaluate soil manipulation and revegetation methods. The engineering design, construction, and properties of the test cover match the upper three layers of the nearby disposal cell cover: a 1-foot armoring of rock riprap, a 6-inch bedding layer of coarse sand and gravel, and a 2-foot protection layer of compacted fine soil. The test cover does not have a radon barrier—cover enhancement tests leave the radon barrier intact. We tested furrowing and ripping as means for creating depressions parallel to the slope contour, bringing soil up into the rock riprap layer, and loosening and blending compacted fine soil with coarse sand and gravel layers. Objectives of these manipulations include (1) enhancing root growth, (2) increasing seed-soil contact, (3) catching runoff water for plant germination and growth, (4) increasing soil water storage capacity, and (5) enhancing deep drying by disrupting the capillary barrier at the interface of the bedding and protection layers.« less

Opportunities and challenges in the use of coal fly ash for soil improvements--a review.

PubMed

Shaheen, Sabry M; Hooda, Peter S; Tsadilas, Christos D

2014-12-01

Coal fly ash (CFA), a by-product of coal combustion has been regarded as a problematic solid waste, mainly due to its potentially toxic trace elements, PTEs (e.g. Cd, Cr, Ni, Pb) and organic compounds (e.g. PCBs, PAHs) content. However, CFA is a useful source of essential plant nutrients (e.g. Ca, Mg, K, P, S, B, Fe, Cu and Zn). Uncontrolled land disposal of CFA is likely to cause undesirable changes in soil conditions, including contamination with PTEs, PAHs and PCBs. Prudent CFA land application offers considerable opportunities, particularly for nutrient supplementation, pH correction and ameliorating soil physical conditions (soil compaction, water retention and drainage). Since CFA contains little or no N and organic carbon, and CFA-borne P is not readily plant available, a mixture of CFA and manure or sewage sludge (SS) is better suited than CFA alone. Additionally, land application of such a mixture can mitigate the mobility of SS-borne PTEs, which is known to increase following cessation of SS application. Research analysis further shows that application of alkaline CFA with or without other amendments can help remediate at least marginally metal contaminated soils by immobilisation of mobile metal forms. CFA land application with SS or other source of organic carbon, N and P can help effectively reclaim/restore mining-affected lands. Given the variability in the nature and composition of CFA (pH, macro- and micro-nutrients) and that of soil (pH, texture and fertility), the choice of CFA (acidic or alkaline and its application rate) needs to consider the properties and problems of the soil. CFA can also be used as a low cost sorbent for the removal of organic and inorganic contaminants from wastewater streams; the disposal of spent CFA however can pose further challenges. Problems in CFA use as a soil amendment occur when it results in undesirable change in soil pH, imbalance in nutrient supply, boron toxicity in plants, excess supply of sulphate and PTEs. These problems, however, are usually associated with excess or inappropriate CFA applications. The levels of PAHs and PCBs in CFA are generally low; their effects on soil biota, uptake by plants and soil persistence, however, need to be assessed. In spite of this, co-application of CFA with manure or SS to land enhances its effectiveness in soil improvements. Copyright © 2014 Elsevier Ltd. All rights reserved.

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

Ruser, R.; Schilling, R.; Steindl, H.

This study was conducted to determine the effect of soil compaction and N fertilization on the fluxes of N{sub 2}O and CH{sub 4} in a soil planted with potato (Solanum tuberosum L.). Fluxes of N{sub 2}O and CH{sub 4} were measured weekly for 1 yr on two differently fertilized fields. For the potato cropping period (May-September) these fluxes were quantified separately for the ridges covering two-thirds of the total field area, and for the uncompacted and the tractor-traffic-compacted interrow soils, each of which made up one-sixth of the field area. The annual N{sub 2}O-N emissions for the low and themore » high rates of N fertilization were 8 and 16 kg ha{sup {minus}1}, respectively. The major part (68%) of the total N{sub 2}O release from the fields during the cropping period was emitted from the compacted tractor tramlines; emissions from the ridges made up only 23%. The annual CH{sub 4}-C uptake was 140 and 118 g ha{sup {minus}1} for the low and high levels of fertilization, respectively. The ridge soil and the uncompacted interrow had mean CH{sub 4}-C oxidation rates of 3.8 and 0.8 {micro}g m{sup {minus}2} h{sup {minus}1}, respectively; however, the tractor-compacted soil released CH{sub 4} at 2.1 {micro}g CH{sub 4}-C m{sup {minus}2} h{sup {minus}1}. The results indicate that soil compaction was probably the main reason for increased N{sub 2}O emission and reduced CH{sub 4} uptake of potato-cropped fields.« less

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

The Influence of Soil Suction on the Shear Strength of Unsaturated Soil

DTIC Science & Technology

1990-09-01

the shear strength parameters c’ and 0’ for montmorillonitic and kaolinitic clays increased following the addition of divalent calcium hydroxide to...503-513. Sridharan, A., Rao, S.N., and Rao, G.V. (1971), "Shear Strength Char- acteristics of Saturated Montmorillonite and Kaolinite Clays," Soils...Summary of Shear Strengths of Unsaturated Specimens of Compacted Kaolinite and Compacted Red Earth (After Murthy, Sridharan and Nagaraj, 1987

Effects of soil compaction on root and root hair morphology: implications for campsite rehabilitation

Treesearch

L. Alessa; C. G. Earnhart

2000-01-01

Recreational use of wild lands can create areas, such as campsites, which may experience soil compaction and a decrease in vegetation cover and diversity. Plants are highly reliant on their roots’ ability to uptake nutrients and water from soil. Any factors that affect the highly specialized root hairs (“feeder cells”) compromise the overall health and survival of the...

Formation of polymer micro-agglomerations in ultralow-binder-content composite based on lunar soil simulant

NASA Astrophysics Data System (ADS)

Chen, Tzehan; Chow, Brian J.; Zhong, Ying; Wang, Meng; Kou, Rui; Qiao, Yu

2018-02-01

We report results from an experiment on high-pressure compaction of lunar soil simulant (LSS) mixed with 2-5 wt% polymer binder. The LSS grains can be strongly held together, forming an inorganic-organic monolith (IOM) with the flexural strength around 30-40 MPa. The compaction pressure, the number of loadings, the binder content, and the compaction duration are important factors. The LSS-based IOM remains strong from -200 °C to 130 °C, and is quite gas permeable.

Micro-structure and Swelling Behaviour of Compacted Clayey Soils: A Quantitative Approach

NASA Astrophysics Data System (ADS)

Ferber, Valéry; Auriol, Jean-Claude; David, Jean-Pierre

In this paper, the clay aggregate volume and inter-aggregate volume in compacted clayey soils are quantified, on the basis of simple hypothesis, using only their water content and dry density. Swelling tests on a highly plastic clay are then interpreted by describing the influence of the inter-aggregate volume before swelling on the total volume of samples after swelling. This approach leads to a linear relation between these latter parameters. Based on these results, a description of the evolution of the microstructure due to imbibition can be proposed. Moreover, this approach enables a general quantification of the influence of initial water content and dry density on the swelling behaviour of compacted clayey soils.

Trees influence preferencial flow and water uptake in tropical savanna

NASA Astrophysics Data System (ADS)

Benegas, Laura; Bargues-Tobella, Aida; Hasselquist, Niles; Malmer, Anders; Ilstedt, Ulrik

2017-04-01

To address potential competition between trees and grasses for soil water, and to disentangle the main process responsible for local soil water dynamics in pasture ecosystems, we conducted a study of the soil water content and water source partitioning of grasses and trees within a pasture in the Copan River catchment, Honduras. We used differences in the 2H/1H (δD) isotopic signature of soil water (δSW) and the local meteoric water line (LMWL; δLMWL) as a relative index of evaporation, following a recent model proposed by Hasselquist et al (under review). The model uses Lc-excess calculated as the absolute value of the difference between measured δD and that predicted by the local meteoric water line (lc-excess = ¦δDM - δDP¦). Lc-excess values close to zero indicate little difference between soil water samples and local precipitation, whereas larger values indicate a greater degree of evaporation .()...(adapted from Landwehr and Coplen, 2006). From the relation between Lc-excess and SWC, we can tease apart different processes by which trees influence local soil water dynamics, where one such processes indicate that if preferential flow, i.e quick flows through macropores that by-pass the soil matrix, is the main pathway for water movement in the soil, then the Lc-excess values of soil water at deeper depths will be closer to zero than those of the surface soil, whereas relatively higher Lc-excess values would indicate increasing dominance of matrix flow. We found that soil underneath trees was wetter than underneath grasses at the dry season and we can relate this with a lack of clear relationship between Lc-excess and SWC and with the treés apparent shift to groundwater sources for root uptake especially in the dry season. Due to the positive correlation between Lc-excess and SWC under trees and due to the lower Lc-excess values found at subsoil below trees during the dry season, we can infer that preferential flow is also facilitated by the trees enhancing its contribution to groundwater recharge. The possible water losses via interception linked with trees on the soil water dynamic was counterbalanced by the positive contribution of trees to preferential flow and groundwater recharge.

Soil compaction and initial height growth of planted ponderosa pine.

Treesearch

P. H. Cochran; Terry. Brock

1985-01-01

Early height growth of ponderosa pine (Pinus ponderosa Dougl. ex Laws.) seedlings planted in clearcuts in central Oregon was negatively correlated with increasing soil bulk density. Change in bulk density accounted for less than half the total variation in height growth. Although many other factors affect the development of seedlings, compaction...

Influence of wood-derived biochar on the physico-mechanical and chemical characteristics of agricultural soils

NASA Astrophysics Data System (ADS)

Ahmed, Ahmed S. F.; Raghavan, Vijaya

2018-01-01

Amendment of soil with biochar has been shown to enhance fertility and increase crop productivity, but the specific influence of biochar on soil workability remains unclear. Select physico-mechanical and chemical properties of clay loam and sandy loam soils were measured after amendment with wood-derived biochar of two particle size ranges (0.5-425 and 425-850 µm) at five dosages ranging from 0.5 to 10% dry weight. Whereas the clay loam soil workability decreased when the finer wood-derived biochar was applied at rates of 6 or 10%, soil fertility was not enhanced. The sandy loam soil, due to Proctor compaction, significantly decreased in bulk density with 6 and 10% wood-derived biochar amendments indicating higher soil resistance to compaction.

Three dimensional, non-linear, finite element analysis of compactable soil interaction with a hyperelastic wheel

NASA Astrophysics Data System (ADS)

Chiroux, Robert Charles

The objective of this research was to produce a three dimensional, non-linear, dynamic simulation of the interaction between a hyperelastic wheel rolling over compactable soil. The finite element models developed to produce the simulation utilized the ABAQUS/Explicit computer code. Within the simulation two separate bodies were modeled, the hyperelastic wheel and a compactable soil-bed. Interaction between the bodies was achieved by allowing them to come in contact but not to penetrate the contact surface. The simulation included dynamic loading of a hyperelastic, rubber tire in contact with compactable soil with an applied constant angular velocity or torque, including a tow load, applied to the wheel hub. The constraints on the wheel model produced a straight and curved path. In addition the simulation included a shear limit between the tire and soil allowing for the introduction of slip. Soil properties were simulated using the Drucker-Prager, Cap Plasticity model available within the ABAQUS/Explicit program. Numerical results obtained from the three dimensional model were compared with related experimental data and showed good correlation for similar conditions. Numerical and experimental data compared well for both stress and wheel rut formation depth under a weight of 5.8 kN and a constant angular velocity applied to the wheel hub. The simulation results provided a demonstration of the benefit of three-dimensional simulation in comparison to previous two-dimensional, plane strain simulations.

Analysis of ramming settlement based on dissipative principle

NASA Astrophysics Data System (ADS)

Fu, Hao; Yu, Kaining; Chen, Changli; Li, Changrong; Wang, Xiuli

2018-03-01

The deformation of soil is a kind of dissipative structure under the action of dynamic compaction. The macroscopic performance of soil to steady state evolution is the change of ramming settlement in the process of dynamic compaction. based on the existing solution of dynamic compaction boundary problem, calculated ramming effectiveness (W) and ramming efficiency coefficient( η ). For the same soil, ramming efficiency coefficient is related to ramming factor λ = M/ρr3. By using the dissipative principle to analyze the law between ramming settlements and ramming times under different ramming energy and soil density, come to the conclusion that: Firstly, with the increase of ramming numbers, ramming settlement tends to a stable value, ramming effectiveness coefficient tends to a stable value. Secondly, under the condition of the same single ramming energy, the soil density of before ramming has effect on ramming effectiveness of previous ramming, almost no effect on ramming effectiveness of subsequent ramming. Thirdly, under the condition of the same soil density, different ramming energy correspond to different steady-state, the cumulative ramming settlement and steady-state increase with ramming energy.

Analysis of ultrasonic effect on powder and application to radioactive sample compaction

NASA Astrophysics Data System (ADS)

Kim, Jungsoon; Sim, Minseop; Kim, Jihyang; Kim, Moojoon

2018-07-01

The effect of ultrasound on powder compaction was analyzed. The decreasing in the friction coefficient of the powder sample is derived theoretically. The compaction rate was improved by the ultrasound. We applied the effect to the compaction of environmental radioactive soil samples. From γ-ray spectroscopy analysis, more radionuclides could be detectable in the sample compacted with ultrasound.

Soil physical land degradation processes

NASA Astrophysics Data System (ADS)

Horn, Rainer

2017-04-01

According to the European Soil Framework Directive (2006) soil compaction is besides water and wind erosion one of the main physical reasons and threats of soil degradation. It is estimated, that 32% of the subsoils in Europe are highly degraded and 18% moderately vulnerable to compaction. The problem is not limited to crop land or forest areas (especially because of non-site adjusted harvesting machines) but is also prevalent in rangelands and grassland, and even in so called natural non-disturbed systems. The main reasons for an intense increase in compacted agricultural or forested regions are the still increasing masses of the machines as well the increased frequency of wheeling under non favorable site conditions. Shear and vibration induced soil deformation enhances the deterioration of soil properties especially if the soil water content is very high and the internal soil strength very low. The same is true for animal trampling in combination with overgrazing of moist to wet pastures which subsequently causes a denser (i.e. reduced proportion of coarse pores with smaller continuity) but still structured soil horizons and will finally end in a compacted platy structure. In combination with high water content and shearing due to trampling therefore results in a complete muddy homogeneous soil with no structure at all. (Krümmelbein et al. 2013) Site managements of arable, forestry or horticulture soils requires a sufficiently rigid pore system which guarantees water, gas and heat exchange, nutrient transport and adsorption as well as an optimal rootability in order to avoid subsoil compaction. Such pore system also guarantees a sufficient microbial activity and composition in order to also decompose the plant etc. debris. It is therefore essential that well structured horizons dominate in soils with at best subangular blocky structure or in the top A- horizons a crumbly structure due to biological activity. In contrast defines the formation of a platy structure down to deeper depth and/or in combination with the deterioration of a continuous pore system an intensely degraded soil. A dominating anisotropy of pore functions causes a lateral soil and water movement. Doerner and Horn (2006), documented the increasing effect of stress and shear affected horizontal anisotropy on the hydraulic and gas permeability which coincides with a retarded gas exchange and an increased proportion of e.g. CO2 or even CH4 in soil pores and hinders the normal population growth. If the internal soil strength is exceeded the microbial composition and activity is converted to anoxia and even results in the emission of CH4 (Haas et al. 2016). Furthermore, the accessibility of nutrient adsorption places as well as connection between the pores within the compacted soils is decreased and results in a retarded ion mass flow and diffusion within the plats and /or in between the soil horizons. How to overcome these negative effects and how to deal with soils adequately according to their internal strength will be presented in the lecture - we need to improve the food production at an preserved land area for growing population. Literature Haas,C., Holthusen,D., Mordhorst,A., Lipiec,J., Horn, R. 2016. Elastic and plastic soil deformation and its influence on emission of greenhouse gases. Int. Agrophys., 30, 173-184 Krümmelbein, J., R.Horn 2013: Cycle of Soil Structure. Soil Degradation 183-198, Advances in Geoecology, 42, Catena Verlag, ISBN: 978-3-923381-59-3

Compacting coastal plain soils changes midrotation loblolly pine allometry by reducing root biomass

Treesearch

Kim H. Ludovici

2008-01-01

Factorial combinations of soil compaction and organic matter removal were replicated at the Long Term Site Productivity study in the Croatan National Forest, near New Bern, North Carolina, USA. Ten years after planting, 18 preselected loblolly pine (Pinus taeda L.) trees were destructively harvested to quantify treatment effects on total above- and...

Harnessing Pavement Power : Developing Renewable Energy Technology in the Public Right-of-Way

DOT National Transportation Integrated Search

2013-09-18

Intelligent Compaction (IC) of soil and asphalt mixes is an innovative approach that has been utilized to achieve uniform, adequate compaction of pavement layers during construction. Commercially available IC products provide machine specific compact...

Roller Compacted Concrete over Soil Cement under Accelerated Loading : Research Project Capsule

DOT National Transportation Integrated Search

2012-09-01

Roller compacted concrete (RCC) is a stiff , zero-slump concrete mixture placed with modifi ed : asphalt paving equipment and compacted by vibratory rollers. Properly designed RCC mixes : can achieve outstanding compressive strengths similar to those...

Relationship between the erosion properties of soils and other parameters

USDA-ARS?s Scientific Manuscript database

Soil parameters are essential for erosion process prediction and ultimately improved model development, especially as they relate to dam and levee failure. Soil parameters including soil texture and structure, soil classification, soil compaction, moisture content, and degree of saturation can play...

Persisting effects of armored military maneuvers on some soils of the Mojave Desert

USGS Publications Warehouse

Prose, D.V.

1985-01-01

Soil compaction and substrate modification produced during large-scale armored military maneuvers in the early 1940s were examined in 1981 at seven sites in California's eastern Mojave Desert Recording penetrometer measurements show that tracks left by a single pass of an M3 "medium" tank have average soil resistance values that are 50% greater than those of the surrounding untracked soil in the upper 20 cm At one site, measurements made along short segments of track that have been visually eliminated by erosion and deposition processes show a 73% increase in penetrometer resistance over adjacent, undisturbed soils Dirt roadways at three former base camp locations could not be penetrated below 5-10 cm because of extreme compaction Soil bulk density was not as sensitive an indicator of soil compaction as was penetrometer resistance Density values in the upper 10 cm of soil are not significantly different between tank tracks and undisturbed soils at most sites, and roadways at two base camps show an average increase in bulk density of only 12% over adjacent soils. Trench excavations across tank tracks show that physical modifications of the substrate can extend vertically beneath a track to a depth of 25 cm and outward from a track's edge to 50 cm These soil disturbances are probably major factors that encourage accelerated soil erosion throughout the manuever area and also retard or prevent the return of vegetation to pre-disturbance conditions ?? 1985 Springer-Verlag New York Inc.

Long-term effects of conventional and reduced tillage systems on soil condition and yield of maize

NASA Astrophysics Data System (ADS)

Rátonyi, Tamás; Széles, Adrienn; Harsányi, Endre

2015-04-01

As a consequence of operations which neglect soil condition and consist of frequent soil disturbance, conventional tillage (primary tillage with autumn ploughing) results in the degradation and compaction of soil structure, as well as the reduction of organic matter. These unfavourable processes pose an increasing economic and environmental protection problem today. The unfavourable physical condition of soils on which conventional tillage was performed indicate the need for preserving methods and tools. The examinations were performed in the multifactorial long-term tillage experiment established at the Látókép experiment site of DE MÉK. The experiment site is located in the Hajdúság loess ridge (Hungary) and its soil is loess-based calcareous chernozem with deep humus layer. The physical soil type is mid-heavy adobe. The long-term experiment has a split-split plot design. The main plots are different tillage methods (autumn ploughing, spring shallow tillage) without replication. In this paper, the effect of conventional and reduced (shallow) tillage methods on soil conditions and maize yield was examined. A manual penetrometer was used to determine the physical condition and compactedness of the soil. The soil moisture content was determined with deep probe measurement (based on capacitive method). In addition to soil analyses, the yield per hectare of different plots was also observed. In reduced tillage, one compacted layer is shown in the soil resistance profile determined with a penetrometer, while there are two compacted layers in autumn ploughing. The highest resistance was measured in the case of primary tillage performed at the same depth for several years in the compacted (pan disk) layer developed under the developed layer in both treatments. The unfavourable impact of spring shallow primary tillage on physical soil conditions is shown by the fact that the compaction of the pan disk exceed the critical limit value of 3 MPa. Over the years, further deterioration of physical conditions were observed below the regularly cultivated layer. In shallow tillage, soil contained more moisture (at 40-50 cm deep and below) than in the ploughed treatment. There are multiple reasons for this phenomenon. This tillage method is moisture preserving as the depth of disturbance (15 cm) is lower than in ploughed treatments (25-30 cm). Soil surface is covered by stem residues after sowing, which may reduce the extent of evaporation. The soil surface CO2 emission was determined based on primary tillage depth, intensity and the period which passed since primary tillage. Spring shallow primary tillage resulted in higher CO2 emission than conventional tillage. The average maize yield was significantly higher in the autumn ploughing treatment (6,6-13,9 t/ha) in the first half (7 years) of the examined period (2000-2014). Higher average yields were observed in two years in the spring shallow tillage treatment and no significant yield difference was observed between tillage treatments in other examined years. Reduced (shallow) tillage increases the risk of near-surface soil compaction and the biological activity of the soil, while it reduces the moisture loss of the soil. Reducing tillage intensity does not necessarily reduce the average yield of the produced crop (maize).

Effects of soil compaction, forest leaf litter and nitrogen fertilizer on two oak species and microbial activity

Treesearch

D. Jordan; F., Jr. Ponder; V. C. Hubbard

2003-01-01

A greenhouse study examined the effects of soil compaction and forest leaf litter on the growth and nitrogen (N) uptake and recovery of red oak (Quercus rubra L.) and scarlet oak (Quercus coccinea Muencch) seedlings and selected microbial activity over a 6-month period. The experiment had a randomized complete block design with...

Soil compaction after yarding of small-diameter Douglas-fir with a small tractor in southwest Oregon.

Treesearch

Michael P. Amaranthus; David E. Steinfeld

1997-01-01

This study evaluated the effect on soil bulk density of yarding small-diameter Douglas-fir (Pseudosuga menziesii var. glauca (Beissn.) Franco) with a small tractor. Levels of compaction were measured before yarding and after one trip, three trips, and six trips by the tractor. Bulk densities in the surface (10 cm) and...

Broadband electromagnetic analysis of compacted kaolin

NASA Astrophysics Data System (ADS)

Bore, Thierry; Wagner, Norman; Cai, Caifang; Scheuermann, Alexander

2017-01-01

The mechanical compaction of soil influences not only the mechanical strength and compressibility but also the hydraulic behavior in terms of hydraulic conductivity and soil suction. At the same time, electric and dielectric parameters are increasingly used to characterize soil and to relate them with mechanic and hydraulic parameters. In the presented study electromagnetic soil properties and suction were measured under defined conditions of standardized compaction tests. The impact of external mechanical stress conditions of nearly pure kaolinite was analyzed on soil suction and broadband electromagnetic soil properties. An experimental procedure was developed and validated to simultaneously determine mechanical, hydraulic and broadband (1 MHz-3 GHz) electromagnetic properties of the porous material. The frequency dependent electromagnetic properties were modeled with a classical mixture equation (advanced Lichtenecker and Rother model, ALRM) and a hydraulic-mechanical-electromagnetic coupling approach was introduced considering water saturation, soil structure (bulk density, porosity), soil suction (pore size distribution, water sorption) as well as electrical conductivity of the aqueous pore solution. Moreover, the relaxation behavior was analyzed with a generalized fractional relaxation model concerning a high-frequency water process and two interface processes extended with an apparent direct current conductivity contribution. The different modeling approaches provide a satisfactory agreement with experimental data for the real part. These results show the potential of broadband electromagnetic approaches for quantitative estimation of the hydraulic state of the soil during densification.

Shear Strength of Remoulding Clay Samples Using Different Methods of Moulding

NASA Astrophysics Data System (ADS)

Norhaliza, W.; Ismail, B.; Azhar, A. T. S.; Nurul, N. J.

2016-07-01

Shear strength for clay soil was required to determine the soil stability. Clay was known as a soil with complex natural formations and very difficult to obtain undisturbed samples at the site. The aim of this paper was to determine the unconfined shear strength of remoulded clay on different methods in moulding samples which were proctor compaction, hand operated soil compacter and miniature mould methods. All the samples were remoulded with the same optimum moisture content (OMC) and density that were 18% and 1880 kg/m3 respectively. The unconfined shear strength results of remoulding clay soils for proctor compaction method was 289.56kPa with the strain 4.8%, hand operated method was 261.66kPa with the strain 4.4% and miniature mould method was 247.52kPa with the strain 3.9%. Based on the proctor compaction method, the reduction percentage of unconfined shear strength of remoulded clay soil of hand operated method was 9.66%, and for miniature mould method was 14.52%. Thus, because there was no significant difference of reduction percentage of unconfined shear strength between three different methods, so it can be concluded that remoulding clay by hand operated method and miniature mould method were accepted and suggested to perform remoulding clay samples by other future researcher. However for comparison, the hand operated method was more suitable to form remoulded clay sample in term of easiness, saving time and less energy for unconfined shear strength determination purposes.

Radial particle-size segregation during packing of particulates into cylindrical containers

USGS Publications Warehouse

Ripple, C.D.; James, R.V.; Rubin, J.

1973-01-01

In a series of experiments, soil materials were placed in long cylindrical containers, using various packing procedures. Soil columns produced by deposition and simultaneous vibratory compaction were dense and axially uniform, but showed significant radial segregation of particle sizes. Similar results were obtained with deposition and simultaneous impact-type compaction when the impacts resulted in significant container "bouncing". The latter procedure, modified to minimize "bouncing" produced dense, uniform soil columns, showing little radial particle-size segregation. Other procedures tested (deposition alone and deposition followed by compaction) did not result in radial segregation, but produced columns showing either relatively low or axially nonuniform densities. Current data suggest that radial particle-size segregation is mainly due to vibration-induced particle circulation in which particles of various sizes have different circulation rates and paths. ?? 1973.

Characterizing soil erosion potential using electrical resistivity imaging : final report.

DOT National Transportation Integrated Search

2017-04-01

The erosion rate, or erodibility, of soil depends on many soil characteristics including: plasticity, : water content, grain size, percent clay, compaction, and shear strength. Many of these characteristics also : influence soil in situ bulk electric...

Characterizing soil erosion potential using electrical resistivity imaging : technical summary.

DOT National Transportation Integrated Search

2017-04-01

The erosion rate, or erodibility, of soil depends on many soil characteristics : including: plasticity, water content, grain size, percent clay, compaction, and shear : strength. Many of these characteristics also influence soil in situ bulk electric...

Effect of Lime on characteristics of consolidation, strength, swelling and plasticity of fine grained soil

NASA Astrophysics Data System (ADS)

Estabragh, A. R.; Bordbar, A. T.; Parsaee, B.; Eskandari, Gh.

2009-04-01

Using Lime as an additive material to clayey soil is one of the best effective technique in building the soil structures to get some purposes such as soil stabilization, soil reinforcement and decreasing soil swelling. In this research the effect of Lime on geotechnical characteristics of a clayey soil was investigated. Soil specimen types used in this study were consisted of clayey soil as the control treatment and clay mixed with different weight fractions of lime, 4, 6, 8 & 10 percent. Some experiments such as CBR, atterburg limits, compaction, consolidation and swelling was conducted on specimens. Results revealed that adding lime to soil would change its physical and mechanical properties. Adding lime increase the compression strength and consolidation coefficient and decrease swelling potential and maximum dry density. According to the results, Atterburg experiments show that presence of lime in soil increase the liquid limit of low plasticity soil and decrease the liquid limit of high plasticity soil, but totally it decreases the plasticity index of soils. Key words: soil stabilization, lime, compression strength, swelling, atterburg limits, compaction

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.

Effects of soil compaction on residual stand growth in central Appalachian hardwood forest: a preliminary case study

Treesearch

Jingxin Wang; Chris LeDoux; Michael Vanderberg; Li Yaoxiang

2006-01-01

A preliminary study that quantified the impacts of soil compaction on residual tree growth associated with ground-based skidding traffic intensity and turn payload size was investigated in the central Appalachian hardwood forest. The field study was carried out on a 20-acre tract of the West Virginia University Research Forest. Skid trails were laid out in 170' -...

Estimation of potential runoff-contributing areas in Kansas using topographic and soil information

USGS Publications Warehouse

Juracek, Kyle E.

1999-01-01

Digital topographic and soil information was used to estimate potential runoff-contributing areas throughout Kansas. The results then were used to compare 91 selected subbasins representing soil, slope, and runoff variability. Potential runoff-contributing areas were estimated collectively for the processes of infiltration-excess and saturation-excess overland flow using a set of environmental conditions that represented very high, high, moderate, low, very low, and extremely low potential runoff. For infiltration-excess overland flow, various rainfall-intensity and soil-permeability values were used. For saturation-excess overland flow, antecedent soil-moisture conditions and a topographic wetness index were used. Results indicated that very low potential-runoff conditions provided the best ability to distinguish the 91 selected subbasins as having relatively high or low potential runoff. The majority of the subbasins with relatively high potential runoff are located in the eastern half of the State where soil permeability generally is less and precipitation typically is greater. The ability to distinguish the subbasins as having relatively high or low potential runoff was possible mostly due to the variability of soil permeability across the State.

Remote Sensing-based Models of Soil Vulnerability to Compaction and Erosion from Off-highway Vehicles

NASA Astrophysics Data System (ADS)

Villarreal, M. L.; Webb, R. H.; Norman, L.; Psillas, J.; Rosenberg, A.; Carmichael, S.; Petrakis, R.; Sparks, P.

2014-12-01

Intensive off-road vehicle use for immigration, smuggling, and security of the United States-Mexico border has prompted concerns about long-term human impacts on sensitive desert ecosystems. To help managers identify areas susceptible to soil erosion from vehicle disturbances, we developed a series of erosion potential models based on factors from the Revised Universal Soil Loss Equation (RUSLE), with particular focus on the management factor (P-factor) and vegetation cover (C-factor). To better express the vulnerability of soils to human disturbances, a soil compaction index (applied as the P-factor) was calculated as the difference in saturated hydrologic conductivity (Ks) between disturbed and undisturbed soils, which was then scaled up to remote sensing-based maps of vehicle tracks and digital soils maps. The C-factor was improved using a satellite-based vegetation index, which was better correlated with estimated ground cover (r2 = 0.77) than data derived from regional land cover maps (r2 = 0.06). RUSLE factors were normalized to give equal weight to all contributing factors, which provided more management-specific information on vulnerable areas where vehicle compaction of sensitive soils intersects with steep slopes and low vegetation cover. Resulting spatial data on vulnerability and erosion potential provide land managers with information to identify critically disturbed areas and potential restoration sites where off-road driving should be restricted to reduce further degradation.

Synchrotron microtomographic quantification of geometrical soil pore characteristics affected by compaction

NASA Astrophysics Data System (ADS)

Udawatta, Ranjith P.; Gantzer, Clark J.; Anderson, Stephen H.; Assouline, Shmuel

2016-05-01

Soil compaction degrades soil structure and affects water, heat, and gas exchange as well as root penetration and crop production. The objective of this study was to use X-ray computed microtomography (CMT) techniques to compare differences in geometrical soil pore parameters as influenced by compaction of two different aggregate size classes. Sieved (diameter < 2 mm and < 0.5 mm) and repacked (1.51 and 1.72 Mg m-3) Hamra soil cores of 5 by 5 mm (average porosities were 0.44 and 0.35) were imaged at 9.6 μm resolution at the Argonne Advanced Photon Source (synchrotron facility) using X-ray CMT. Images of 58.9 mm3 volume were analyzed using 3-Dimensional Medial Axis (3-DMA) software. Geometrical characteristics of the spatial distributions of pore structures (pore radii, volume, connectivity, path length, and tortuosity) were numerically investigated. Results show that the coordination number (CN) distribution and path length (PL) measured from the medial axis were reasonably fit by exponential relationships P(CN) = 10-CN/Co and P(PL) = 10-PL/PLo, respectively, where Co and PLo are the corresponding characteristic constants. Compaction reduced porosity, average pore size, number of pores, and characteristic constants. The average pore radii (63.7 and 61 µm; p < 0.04), largest pore volume (1.58 and 0.58 mm3; p = 0.06), number of pores (55 and 50; p = 0.09), and characteristic coordination number (3.74 and 3.94; p = 0.02) were significantly different between the low-density than the high-density treatment. Aggregate size also influenced measured geometrical pore parameters. This analytical technique provides a tool for assessing changes in soil pores that affect hydraulic properties and thereby provides information to assist in assessment of soil management systems.

Supplementing seed banks to rehabilitate disturbed Mojave Desert shrublands: where do all the seeds go?

USGS Publications Warehouse

DeFalco, Lesley A.; Esque, Todd C.; Nicklas, Melissa B.; Kane, Jeffrey M.

2012-01-01

Revegetation of degraded arid lands often involves supplementing impoverished seed banks and improving the seedbed, yet these approaches frequently fail. To understand these failures, we tracked the fates of seeds for six shrub species that were broadcast across two contrasting surface disturbances common to the Mojave Desert—sites compacted by concentrated vehicle use and trenched sites where topsoil and subsurface soils were mixed. We evaluated seedbed treatments that enhance soil-seed contact (tackifier) and create surface roughness while reducing soil bulk density (harrowing). We also explored whether seed harvesting by granivores and seedling suppression by non-native annuals influence the success of broadcast seeding in revegetating degraded shrublands. Ten weeks after treatments, seeds readily moved off of experimental plots in untreated compacted sites, but seed movements were reduced 32% by tackifier and 55% through harrowing. Harrowing promoted seedling emergence in compacted sites, particularly for the early-colonizing species Encelia farinosa, but tackifier was largely ineffective. The inherent surface roughness of trenched sites retained three times the number of seeds than compacted sites, but soil mixing during trench development likely altered the suitability of the seedbed thus resulting in poor seedling emergence. Non-native annuals had little influence on seed fates during our study. In contrast, the prevalence of harvester ants increased seed removal on compacted sites, whereas rodent activity influenced removal on trenched sites. Future success of broadcast seeding in arid lands depends on evaluating disturbance characteristics prior to seeding and selecting appropriate species and seasons for application.

Identifying synergies between water resource protection and farm business objectives: the role of soil management

NASA Astrophysics Data System (ADS)

Stoate, Chris

2017-04-01

We use a 3,000 ha BACI experiment on clay soils in central England as a focus for exploring synergies between Water Framework Directive targets for water quality (sediment, nutrients and pesticides) and crop production objectives of farm businesses. Based on base of catchment annual sediment loads, we estimate annual soil loss from farmland to be in the order of 0.3 - 0.6 tonnes per hectare. This has impacts on aquatic ecology, reservoir storage capacity and downstream flood risk through sedimentation of drainage channels. Soil loss is relatively low in a European context but reflects poorly functioning soils with high runoff risk, and poor crop performance due to compaction, low organic matter, waterlogging, and competition from the grass weed, blackgrass (Alopecuris alopoides). We use a range of mechanisms to increase farmers' awareness, understanding and motivation for improving soil management to meet multiple public and private benefits of soil function and present results for soil organic matter testing, earthworm surveying, and horizontal and vertical soil compaction mapping.

Harvest traffic monitoring and soil physical response in a pine plantation

Treesearch

Emily A. Carter; Timothy P. McDonald; John L. Torbert

2000-01-01

Mechanized forest harvest operations induce changes in soil physical properties, which have the potential to impact soil sustainability and forest productivity. The assessment of soil compaction and its spatial variability has been determined previously through the identification and tabulation of visual soil disturbance classes and soil physical changes associated...

Thermal signature characteristics of vehicle/terrain interaction disturbances: implications for battlefield vehicle classification.

PubMed

Eastes, John W; Mason, George L; Kusinger, Alan E

2004-05-01

Thermal emissivity spectra (8-14 microm) of track impressions/background were determined in conjunction with operation of six military vehicle types, T-72 and M1 Tanks, an M2 Bradley Fighting Vehicle, a 5-ton truck, a D7 tractor, and a High Mobility Multipurpose Wheeled Vehicle (HMMWV), over diverse soil surfaces to determine if vehicle type could be related to track thermal signatures. Results suggest soil compaction and fragmentation/pulverization are primary parameters affecting track signatures and that soil and vehicle/terrain-contact type determine which parameter dominates. Steel-tracked vehicles exert relatively low ground-contact pressure but tend to fragment/pulverize soil more so than do rubber-tired vehicles, which tend mainly to compact. In quartz-rich, lean clay soil tracked vehicles produced impressions with spectral contrast of the quartz reststrahlen features decreased from that of the background. At the same time, 5-ton truck tracks exhibited increased contrast on the same surface, suggesting that steel tracks fragmented soil while rubber tires mainly produced compaction. The structure of materials such as sand and moist clay-rich river sediment makes them less subject to further fragmentation/pulverization; thus, compaction was the main factor affecting signatures in these media, and both tracked and wheeled vehicles created impressions with increased spectral contrast on these surfaces. These results suggest that remotely sensed thermal signatures could differentiate tracked and wheeled vehicles on terrain in many areas of the world of strategic interest. Significant applications include distinguishing visually/spectrally identical lightweight decoys from actual threat vehicles.

Nitrogen Excess in North American Ecosystems: Predisposing Factors, Ecosystem Responses, and Management Strategies

Treesearch

Mark E. Fenn; Mark A. Poth; John D. Aber; Jill S. Baron; Bernard T. Bormann; Dale W. Johnson; A. Dennis Lemly; Steven G. McNulty; Douglas F. Ryan; Robert Stottlemyer

1998-01-01

Most forests in North America remain nitrogen limited, although recent studies have identified forested areas that exhibit symptoms of N excess, analogous to overfertilization of arable land. Nitrogen excess in watersheds is detrimental because of disruptions in plant/soil nutrient relations, increased soil acidification and aluminum mobility, increased emissions of...

MEASUREMENTS OF INFILTRATION RATES IN COMPACTED URBAN SOILS

EPA Science Inventory

Previous research hs identified significant reductions in infiltration rates in disturbed urban soils, More than 150 prior tests were conducted in predominately sandy and clayey urban soils in the Birmingham and Mobile, AL areas. Infiltration in Clayey soils ws found to be affect...

Impact of disturbance on 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. These crusts are particularly sensitive to compaction/fracturing disturbances such as livest...

Effects of compaction and soil moisture on American burying beetles.

DOT National Transportation Integrated Search

2016-12-25

Silphid beetles in the genus Nicrophorus bury themselves during periods of inactivity, however, the influence of soil characteristics on burial behavior remains unclear. We examined soil preferences of the federally endangered Nicrophorus americanus,...

Chemical modification of uniform soils and soils with high/low plasticity index.

DOT National Transportation Integrated Search

2016-08-01

The addition of chemicals into the subgrade has been widely used during construction to improve the soil properties. The chemicals, often Lime Kiln Dust (LKD) and Portland cement, are added to the soil to improve its workability, compactability and e...

Early understory biomass response to organic matter removal and soil compaction

Treesearch

Felix Jr. Ponder

2008-01-01

In the Missouri Ozarks, 6 and 8 years after treatment, understory biomass differences between bole only harvesting (BO) and whole-tree plus forest floor harvesting were not different; neither were there understory biomass differences between no compaction and severe compaction. Separation of the biomass into broad species categories (trees, shrubs, annuals, perennials...

Deployment Area Selection and Land Withdrawal/Acquisition. M-X/MPS (M-X/Multiple Protective Shelter) Environmental Technical Report. Mitigations.

DTIC Science & Technology

1981-10-02

structure. Compacted soils are difficult to revegetate without adequate treatment . In addition, compacted soils have lower infiltration rates * which result...Reno, Nevada. August 1976). Erosion and sediment can be controlled on construction sites if certain principles are followed in the use of treatment of...If successful erosion control treatment is applied to the land in the watershed, sediment production can be reduced to

Supplementing seed banks to rehabilitate disturbed Mojave Desert shrublands: Where do all the seeds go?

USGS Publications Warehouse

DeFalco, L.A.; Esque, T.C.; Nicklas, M.B.; Kane, J.M.

2012-01-01

Revegetation of degraded arid lands often involves supplementing impoverished seed banks and improving the seedbed, yet these approaches frequently fail. To understand these failures, we tracked the fates of seeds for six shrub species that were broadcast across two contrasting surface disturbances common to the Mojave Desert-sites compacted by concentrated vehicle use and trenched sites where topsoil and subsurface soils were mixed. We evaluated seedbed treatments that enhance soil-seed contact (tackifier) and create surface roughness while reducing soil bulk density (harrowing). We also explored whether seed harvesting by granivores and seedling suppression by non-native annuals influence the success of broadcast seeding in revegetating degraded shrublands. Ten weeks after treatments, seeds readily moved off of experimental plots in untreated compacted sites, but seed movements were reduced 32% by tackifier and 55% through harrowing. Harrowing promoted seedling emergence in compacted sites, particularly for the early-colonizing species Encelia farinosa, but tackifier was largely ineffective. The inherent surface roughness of trenched sites retained three times the number of seeds than compacted sites, but soil mixing during trench development likely altered the suitability of the seedbed thus resulting in poor seedling emergence. Non-native annuals had little influence on seed fates during our study. In contrast, the prevalence of harvester ants increased seed removal on compacted sites, whereas rodent activity influenced removal on trenched sites. Future success of broadcast seeding in arid lands depends on evaluating disturbance characteristics prior to seeding and selecting appropriate species and seasons for application. ?? 2010 Society for Ecological Restoration International.

Effects of Machine Traffic on the Physical Properties of Ash-Cap Soils

Treesearch

Leonard R. Johnson; Debbie Page-Dumroese; Han-Sup Han

2007-01-01

With pressure and vibration on a soil, air spaces between soil particles can be reduced by displaced soil particles. Activity associated with heavy machine traffic increases the density of the soil and can also increase the resistance of the soil to penetration. This paper reviews research related to disturbance of forest soils with a primary focus on compaction in ash...

Physical properties of forest soils

Treesearch

Charles H. Perry; Michael C. Amacher

2007-01-01

Why Are Physical Properties of the Soil Important? The soil quality indicator, when combined with other data collected by the FIA program, can indicate the current rates of soil erosion, the extent and intensity of soil compaction, and some basic physical properties of the forest floor and the top 20 cm of soil. In this report, two particular physical properties of the...

Forest Soil Productivity on the Southern Long-Term Soil Productivity Sites at Age 5

Treesearch

D. Andrew Scott; Allan E. Tiarks; Felipe G. Sanchez; Michael Elliott-Smith; Rick Stagg

2004-01-01

Forest management operations have the potential to reduce soil productivity through organic matter and nutrient removal and soil compaction. We measured pine volume, bulk density, and soil and foliar nitrogen and phosphorus at age 5 on the 13 southern Long-Term Soil Productivity study sites. The treatments were organic matter removal [bole only (BO), whole tree (WT),...

CONSTRUCTION, MONITORING, AND PERFORMANCE OF TWO SOIL LINERS

EPA Science Inventory

A prototype soil liner and a field-scale soil liner were constructed to test whether compacted soil barrier systems could be built to meet the standard set by the U.S. Environmental Protection Agency (EPA) for saturated hydraulic conductivity (< 1 x 10'7 cm/s). In situ ponded inf...

[Heavy metal pollution characteristics and ecological risk analysis for soil around Haining electroplating industrial park].

PubMed

Li, Jiong-Hui; Weng, Shan; Fang, Jing; Huang, Jia-Lei; Lu, Fang-Hua; Lu, Yu-Hao; Zhang, Hong-Ming

2014-04-01

The pollution status and potential ecological risks of heavy metal in soils around Haining electroplating industrial park were studied. Hakanson index approach was used to assess the ecological hazards of heavy metals in soils. Results showed that average concentrations of six heavy metals (Cu, Ni, Pb, Zn, Cd and Cr) in the soils were lower than the secondary criteria of environmental quality standard for soils, indicating limited harmful effects on the plants and the environment in general. Though the average soil concentrations were low, heavy metal concentrations in six sampling points located at the side of road still exceeded the criteria, with excessive rate of 13%. Statistic analysis showed that concentrations of Cu and Cd in roadside soils were significantly higher than those in non-roadside soils, indicating that the excessive heavy metal accumulations in the soil closely related with traffic transport. The average potential ecological hazard index of soils around Haining electroplating industrial park was 46.6, suggesting a slightly ecological harm. However, the potential ecological hazard index of soils with excessive heavy metals was 220-278, suggesting the medium ecological hazards. Cd was the most seriously ecological hazard factor.

Effective depth of soil compaction in relation to applied compactive energy.

DOT National Transportation Integrated Search

2015-02-01

The determination of appropriate lift thickness used in the embankment construction has important economic : and engineering implications in the design, construction, and performance of transportation systems. Department : of Transportations (DOTs) a...

Implementation of Controlled Traffic in the Canadian Prairies: Soil and Plant Dynamics under Simulated and Field Conditions

NASA Astrophysics Data System (ADS)

Guenette, Kris; Hernandez-Ramirez, Guillermo

2017-04-01

Achieving resiliency in agroecosystems may be accomplished through the incorporation of contemporary management systems and the diversification of crop rotations with pulse crops, such as controlled traffic farming (CTF) and faba beans (Vicia faba L.). As these practices become more common in the Canadian Prairies, it is imperative to have a well-rounded understanding of how faba beans interact with the soil-plant-atmosphere continuum in conditions found in contemporary management systems. Simulated field conditions emulated soil compaction found in both the trafficked and un-trafficked areas of a CTF system, in which the presence of high water availability was shown to offset the negative results of large applications of compactive effort. Furthermore, low water availability exacerbated differences in plant responses between compaction treatments. The simulated treatment of 1.2 gcm-3 coupled with high water content yielded the most optimal results for most measured parameters, with a contrasting detrimental treatment of 1.4 gcm-3 at low water availability. The simulated field conditions were further bridged through an analysis of two commercial sites in Alberta, Canada that compared both trafficked and un-trafficked soil properties. Soil properties such as available nitrogen (AN), pH, soil total nitrogen (STN), soil organic carbon (SOC), bulk density, macroporosity, soil quality S-Index, plant available water capacity (PAWC) and unsaturated hydraulic conductivity (Km) were analysed and compared among trafficked and un-trafficked areas. The measured soil physical and hydraulic properties of bulk density, macroporosity, S-Index, PAWC and Km were shown to be heavily influenced by the CTF traffic regime, while soil nutrient properties of AN, pH, STN SOC were determined to be dependent on both management and landscape features.

Compact Radiometers Expand Climate Knowledge

NASA Technical Reports Server (NTRS)

2010-01-01

To gain a better understanding of Earth's water, energy, and carbon cycles, NASA plans to embark on the Soil Moisture Active and Passive mission in 2015. To prepare, Goddard Space Flight Center provided Small Business Innovation Research (SBIR) funding to ProSensing Inc., of Amherst, Massachusetts, to develop a compact ultrastable radiometer for sea surface salinity and soil moisture mapping. ProSensing incorporated small, low-cost, high-performance elements into just a few circuit boards and now offers two lightweight radiometers commercially. Government research agencies, university research groups, and large corporations around the world are using the devices for mapping soil moisture, ocean salinity, and wind speed.

Synchrotron Microtomographic Quantification of Geometrical Soil Pore Characteristics Affected by Compaction

NASA Astrophysics Data System (ADS)

Udawatta, Ranjith; Gantzer, Clark; Anderson, Stephen; Assouline, Shmuel

2015-04-01

Soil compaction degrades soil structure and affects water, heat, and gas exchange as well as root penetration and crop production. The objective of this study was to use X-ray computed microtomography (CMT) techniques to compare differences in geometrical soil pore parameters as influenced by compaction of two different aggregate size classes. Sieved (diam. < 2mm and < 0.5mm) and repacked (1.51 and 1.72 Mg m-3) Hamra soil cores of 5- by 5-mm (average porosities were 0.44 and 0.35) were imaged at 9.6-micrometer resolution at the Argonne Advanced Photon Source (synchrotron facility) using X-ray computed microtomography. Images of 58.9 mm3 volume were analyzed using 3-Dimensional Medial Axis (3DMA) software. Geometrical characteristics of the spatial distributions of pore structures (pore radii, volume, connectivity, path length, and tortuosity) were numerically investigated. Results show that the coordination number (CN) distribution and path length (PL) measured from the medial axis were reasonably fit by exponential relationships P(CN)=10-CN/Co and P(PL)=10-PL/PLo, respectively, where Co and PLo are the corresponding characteristic constants. Compaction reduced porosity, average pore size, number of pores, and characteristic constants. The average pore radii (64 and 61 μm; p<0.04), largest pore volume (1.6 and 0.6 mm3; p=0.06), number of pores (55 and 50; p=0.09), characteristic coordination number (6.3 and 6.0; p=0.09), and characteristic path length number (116 and 105; p=0.001) were significantly greater in the low density than the high density treatment. Aggregate size also influenced measured geometrical pore parameters. This analytical technique provides a tool for assessing changes in soil pores that affect hydraulic properties and thereby provides information to assist in assessment of soil management systems.

Synchrotron microtomographic quantification of geometrical soil pore characteristics affected by compaction

NASA Astrophysics Data System (ADS)

Udawatta, R. P.; Gantzer, C. J.; Anderson, S. H.; Assouline, S.

2015-07-01

Soil compaction degrades soil structure and affects water, heat, and gas exchange as well as root penetration and crop production. The objective of this study was to use X-ray computed microtomography (CMT) techniques to compare differences in geometrical soil pore parameters as influenced by compaction of two different aggregate size classes. Sieved (diam. < 2 mm and < 0.5 mm) and repacked (1.51 and 1.72 Mg m-3) Hamra soil cores of 5- by 5 mm (average porosities were 0.44 and 0.35) were imaged at 9.6-micrometer resolution at the Argonne Advanced Photon Source (synchrotron facility) using X-ray computed microtomography. Images of 58.9 mm3 volume were analyzed using 3-Dimensional Medial Axis (3DMA) software. Geometrical characteristics of the spatial distributions of pore structures (pore radii, volume, connectivity, path length, and tortuosity) were numerically investigated. Results show that the coordination number (CN) distribution and path length (PL) measured from the medial axis were reasonably fit by exponential relationships P(CN) = 10-CN/Co and P(PL) = 10-PL/PLo, respectively, where Co and PLo are the corresponding characteristic constants. Compaction reduced porosity, average pore size, number of pores, and characteristic constants. The average pore radii (63.7 and 61 μm; p < 0.04), largest pore volume (1.58 and 0.58 mm3; p = 0.06), number of pores (55 and 50; p = 0.09), characteristic coordination number (6.32 and 5.94; p = 0.09), and characteristic path length number (116 and 105; p = 0.001) were significantly greater in the low density than the high density treatment. Aggregate size also influenced measured geometrical pore parameters. This analytical technique provides a tool for assessing changes in soil pores that affect hydraulic properties and thereby provides information to assist in assessment of soil management systems.

Preparation of a Frozen Regolith Simulant Bed for ISRU Component Testing in a Vacuum Chamber

NASA Technical Reports Server (NTRS)

Klenhenz, Julie; Linne, Diane

2013-01-01

In-Situ Resource Utilization (ISRU) systems and components have undergone extensive laboratory and field tests to expose hardware to relevant soil environments. The next step is to combine these soil environments with relevant pressure and temperature conditions. Previous testing has demonstrated how to incorporate large bins of unconsolidated lunar regolith into sufficiently sized vacuum chambers. In order to create appropriate depth dependent soil characteristics that are needed to test drilling operations for the lunar surface, the regolith simulant bed must by properly compacted and frozen. While small cryogenic simulant beds have been created for laboratory tests, this scale effort will allow testing of a full 1m drill which has been developed for a potential lunar prospector mission. Compacted bulk densities were measured at various moisture contents for GRC-3 and Chenobi regolith simulants. Vibrational compaction methods were compared with the previously used hammer compaction, or "Proctor", method. All testing was done per ASTM standard methods. A full 6.13 m3 simulant bed with 6 percent moisture by weight was prepared, compacted in layers, and frozen in a commercial freezer. Temperature and desiccation data was collected to determine logistics for preparation and transport of the simulant bed for thermal vacuum testing. Once in the vacuum facility, the simulant bed will be cryogenically frozen with liquid nitrogen. These cryogenic vacuum tests are underway, but results will not be included in this manuscript.

Study on the Effect of Steel Wheel and Ground on Single Steel Vibratory Roller

NASA Astrophysics Data System (ADS)

Li, Jiabo; You, Guanghui; Qiao, Jiabin; Ye, Min; Guo, Jin; Zhang, Hongyang

2018-03-01

In the compacting operation of single drum vibratory roller, the forces acting on the foundation of drum include the weight of the drum, the weight of the frame, the exciting force and so on. Based on the theoretical study of ground mechanics, this paper analyzes and calculates the forces acting on the steel wheel and the ground, and obtains the distribution of the laminar stress in the ground when the working plane vibrates. Derive the formula of dynamic compressive stress and static compressive stress in the foundation during vibration compaction. Through the compaction test of the soil trough of 20T single drum roller, the compressive stress data of the soil hydraulic field are obtained. The data of the dynamic compressive stress and the static compressive stress of each layer during the third compaction are obtained, and the theoretical research is verified.

Excessive sulfur supply reduces cadmium accumulation in brown rice (Oryza sativa L.).

PubMed

Fan, Jian-Ling; Hu, Zheng-Yi; Ziadi, Noura; Xia, Xu; Wu, Cong-Yang-Hui

2010-02-01

Human activities have resulted in cadmium (Cd) and sulfur (S) accumulation in paddy soils in parts of southern China. A combined soil-sand pot experiment was conducted to investigate the influence of excessive S supply on iron plaque formation and Cd accumulation in rice plants, using two Cd levels (0, 1.5 mg kg(-1)) combined with three S concentrations (0, 60, 120 mg kg(-1)). The results showed that excessive S supply significantly decreased Cd accumulation in brown rice due to the decrease of Cd availability and the increase of glutathione in rice leaves. But excessive S supply obviously increased Cd accumulation in roots due to the decrease of iron plaque formation on the root surface of rice. Therefore, excessive S supply may result in loss of rice yield, but it could effectively reduce Cd accumulation in brown rice exposed to Cd contaminated soils. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

Characteristics and engineering properties of the soft soil layer in highway soil subgrades.

DOT National Transportation Integrated Search

2006-06-01

The objective of this research was to examine the conditions and characteristics of soil subgrades that had been stabilized using mechanical compaction. Goals of the study are to identify and examine the engineering properties and behavior of the ...

STUDIES ON CONTAMINANT BIODEGRADATION IN SLURRY, WAFER, AND COMPACTED SOIL TUBE REACTORS

EPA Science Inventory

A systematic experimental approach is presented to quantitatively evaluate biodegradation rates in intact soil systems. Knowledge of bioremediation rates in intact soil systems is important for evaluating the efficacy of in-situ biodegradation and approaches for enhancing degrad...

Soil degradation: Will humankind ever learn?

USDA-ARS?s Scientific Manuscript database

Soil degradation is a global problem caused by many factors including excessive tillage, inappropriate crop rotations, excessive grazing or crop residue removal, deforestation, mining, construction and urban sprawl. To meet the needs of an expanding global population, it is essential for humankind t...

Long-term effects of grazing management and buffer strips on soil erosion from pastures

USDA-ARS?s Scientific Manuscript database

High grazing pressure can lead to soil erosion in pastures by compacting soil and increasing runoff and sediment delivery to waterways. Limited information exists on the effects of grazing management and best management practices (BMPs), such as buffer strips, on soil erosion from pastures. The obje...

Ameliorating effects of designer biochars in a hard-setting subsoil layer: soil fertility and plant biomass

USDA-ARS?s Scientific Manuscript database

Soils in the southeastern U.S. Coastal Plain region have meager soil fertility and frequently have compacted subsoil layers (E horizon). Designer biochar has gained global interest as an amendment to improve the fertility, chemical, and physical properties of degraded agricultural soils. We hypothes...

DEVELOPMENT OF BIOAVAILABILITY AND BIOKINETICS DETERMINATION METHODS FOR ORGANIC POLLUTANTS IN SOIL TO ENHANCE IN-SITU AND ON-SITE BIOREMEDIATION

EPA Science Inventory

Determination of biodegradation rates of organics in soil slurry and compacted soil systems is essential for evaluating the efficacy of bioremediation for treatment of contaminated soils. In this paper, a systematic protocol has been developed for evaluating bioknetic and transp...

40 CFR 761.75 - Chemical waste landfills.

Code of Federal Regulations, 2014 CFR

2014-07-01

... for the disposal of PCBs and PCB Items are as follows: (1) Soils. The landfill site shall be located..., the soil shall have a high clay and silt content with the following parameters: (i) In-place soil thickness, 4 feet or compacted soil liner thickness, 3 feet; (ii) Permeability (cm/sec), equal to or less...

40 CFR 761.75 - Chemical waste landfills.

Code of Federal Regulations, 2013 CFR

2013-07-01

... for the disposal of PCBs and PCB Items are as follows: (1) Soils. The landfill site shall be located..., the soil shall have a high clay and silt content with the following parameters: (i) In-place soil thickness, 4 feet or compacted soil liner thickness, 3 feet; (ii) Permeability (cm/sec), equal to or less...

Applicability of recycled aggregates in concrete piles for soft soil improvement.

PubMed

Medeiros-Junior, Ronaldo A; Balestra, Carlos Et; Lima, Maryangela G

2017-01-01

The expressive generation of construction and demolition waste is stimulating several studies for reusing this material. The improvement of soft soils by concrete compaction piles has been widely applied for 40 years in some Brazilian cities. This technique is used to improve the bearing capacity of soft soils, allowing executing shallow foundations instead of deep foundations. The compaction piles use a high volume of material. This article explored the possibility of using recycled aggregates from construction waste to replace the natural aggregates in order to improve the bearing capacity of the soft soil, regarding its compressive strength. Construction wastes from different stages of a construction were used in order to make samples of concrete with recycled aggregates. The strength of concretes with natural aggregates was compared with the strength of concretes with recycled (fine and coarse) aggregates. Results show that all samples met the minimum compressive strength specified for compaction piles used to improve the bearing capacity of soft soils. The concrete with recycled aggregate from the structural stage had even higher resistances than the concrete with natural aggregates. This behaviour was attributed to the large amount of cementitious materials in the composition of this type of concrete. It was also observed that concrete with recycled fine aggregate has a superior resistance to concrete with recycled coarse aggregate.

The Estimation of Compaction Parameter Values Based on Soil Properties Values Stabilized with Portland Cement

NASA Astrophysics Data System (ADS)

Lubis, A. S.; Muis, Z. A.; Pasaribu, M. I.

2017-03-01

The strength and durability of pavement construction is highly dependent on the properties and subgrade bearing capacity. This then led to the idea of the selection methods to estimate the density of the soil with the proper implementation of the system, fast and economical. This study aims to estimate the compaction parameter value namely the maximum dry unit weight (γd max) and optimum moisture content (wopt) of the soil properties value that stabilized with Portland Cement. Tests conducted in the laboratory of soil mechanics to determine the index properties (fines and liquid limit) and Standard Compaction Test. Soil samples that have Plasticity Index (PI) between 0-15% then mixed with Portland Cement (PC) with variations of 2%, 4%, 6%, 8% and 10%, each 10 samples. The results showed that the maximum dry unit weight (γd max) and wopt has a significant relationship with percent fines, liquid limit and the percentation of cement. Equation for the estimated maximum dry unit weight (γd max) = 1.782 - 0.011*LL + 0,000*F + 0.006*PS with R2 = 0.915 and the estimated optimum moisture content (wopt) = 3.441 + 0.594*LL + 0,025*F + 0,024*PS with R2 = 0.726.

Chemically stabilized soils.

DOT National Transportation Integrated Search

2009-12-01

The objective of this study was to conduct laboratory evaluations to quantify the effects of compaction and moisture conditions on the strength of chemically treated soils typical utilized in pavement construction in Mississippi.

Relationships between basic soils-engineering equations and basic ground-water flow equations

USGS Publications Warehouse

Jorgensen, Donald G.

1980-01-01

The many varied though related terms developed by ground-water hydrologists and by soils engineers are useful to each discipline, but their differences in terminology hinder the use of related information in interdisciplinary studies. Equations for the Terzaghi theory of consolidation and equations for ground-water flow are identical under specific conditions. A combination of the two sets of equations relates porosity to void ratio and relates the modulus of elasticity to the coefficient of compressibility, coefficient of volume compressibility, compression index, coefficient of consolidation, specific storage, and ultimate compaction. Also, transient ground-water flow is related to coefficient of consolidation, rate of soil compaction, and hydraulic conductivity. Examples show that soils-engineering data and concepts are useful to solution of problems in ground-water hydrology.

Effect of soil compaction and biomass removal on soil CO2 efflux in a Missouri forest

Treesearch

Felix, Jr. Ponder

2005-01-01

Forest disturbances associated with harvesting activities can affect soil properties and soil respiration. A soda-lime technique was used to measure soil carbon dioxide (CO2) efflux rates in clearcut plots of a Missouri oak-hickory (Quercus spp. L.-Carya spp. Nutt.) forest 4 years after being treated with two levels of forest...

The influence of organic matter content and media compaction on the dispersal of entomopathogenic nematodes with different foraging strategies.

PubMed

Kapranas, Apostolos; Maher, Abigail M D; Griffin, Christine T

2017-12-01

In laboratory experiments, we investigated how media with varying ratio of peat:sand and two levels of compaction influence dispersal success of entomopathogenic nematode (EPN) species with different foraging strategies: Steinernema carpocapsae (ambusher), Heterorhabditis downesi (cruiser) and Steinernema feltiae (intermediate). Success was measured by the numbers of nematodes moving through a 4 cm column and invading a wax moth larva. We found that both compaction and increasing peat content generally decreased EPN infective juvenile (IJ) success for all three species. Of the three species, H. downesi was the least affected by peat content, and S. carpocapsae was the most adversely influenced by compaction. In addition, sex ratios of the invading IJs of the two Steinernema species were differentially influenced by peat content, and in the case of S. feltiae, sex ratio was also affected by compaction. This indicates that dispersal of male and female IJs is differentially affected by soil parameters and that this differentiation is species-specific. In conclusion, our study shows that organic matter: sand ratio and soil compaction have a marked influence on EPN foraging behaviour with implications for harnessing them as biological pest control agents.

Rapid field detection of moisture content for base and subgrade : technical report.

DOT National Transportation Integrated Search

2015-03-01

Mixing and compacting soil and flexible base pavement materials at the proper moisture content is critical : for obtaining adequate compaction and meeting construction specification requirements. This project sought : to evaluate rapid non-nuclear te...

Systems approach critical to agroecosystems management

USDA-ARS?s Scientific Manuscript database

Sustainable dryland agriculture in the semi-arid Great Plains of the U.S. depends on achieving economic yields while maintaining soil resources. The traditional system of conventional tillage wheat-fallow was vulnerable to excessive soil erosion which resulted in excessive organic matter loss. No-...

The patterns and implications of diurnal variations in d-excess of plant water, shallow soil water and air moisture

NASA Astrophysics Data System (ADS)

Zhao, L.; Wang, L.; Xiao, H.; Cheng, G.; Ruan, Y.; Zhou, M.; Wang, F.

2014-04-01

Deuterium excess (d-excess) of air moisture is traditionally considered as a conservative tracer of oceanic evaporation conditions. Recent studies challenge this view and emphasize the importance of vegetation activity in controlling the dynamics of air moisture d-excess. However direct field observations supporting the role of vegetation in d-excess variations is not well documented. In this study, we quantified d-excess of air moisture, leaf and xylem water of multiple dominant species as well as shallow soil water (5 and 10 cm) at hourly interval during three extensive field campaigns at two climatically different locations within the Heihe River Basin. The results showed that with the increase of temperature (T) and decrease of relative humidity (RH), the δD-δ18O plots of leaf water, xylem water and shallow soil water deviated gradually from their corresponding local meteoric water line. There were significant differences in d-excess values among different water pools at all the study sites. The most positive d-excess values were found in air moisture (9.3‰) and the most negative d-excess values (-85.6‰) were found in leaf water. The d-excess values of air moisture (dmoisture) and leaf water (dleaf) during the sunny days, and shallow soil water (dsoil) during the first sunny day after rain event showed strong diurnal patterns. There were significantly positive relationships between dleaf and RH and negative relationships between dmoisture and RH. The correlations of dleaf and dmoisture with T were opposite to their relationships with RH. In addition, we found the opposite diurnal variations for dleaf and dmoisture during the sunny day, and for dleaf during the sunny days, and shallow soil water dsoil and dmoisture during the first sunny day after rain event. Significant negative relationships were found between dleaf and dmoisture in all the sites during the sunny day. Our results provide direct evidence that dmoisture of the surface air at continental locations can be significantly altered by local processes, especially plant transpiration during the sunny days. The role of shallow soil water on dmoisture is generally much smaller but could be large at the sunny day right after rainfall events.

Won’t soil be damaged if cattle graze cover crops?

USDA-ARS?s Scientific Manuscript database

Integration of crops and livestock could provide economic benefits to producers by intensifying land use and improving resource efficiency, but how this management might affect soil compaction, water infiltration, and soil strength has not been well documented. Key factors in balancing cattle produ...

Improvements of soil quality for increased food production in Norway

NASA Astrophysics Data System (ADS)

Øygarden, Lillian; Klakegg, Ove; Børresen, Trond; Krogstad, Tore; Kjersti Uhlen, Anne

2016-04-01

Since the 1990ties, agricultural land in use in Norway has diminished and yields per hectare for cereals and forages have stagnated. An expert panel appointed to advice on how to increase Norwegian grain production emphasizes low profitability and poor soil quality as limiting factors. A White Paper from the Norwegian Government, Report No.9 (2011-2012), stated that the main goal for the agricultural sector is to increase food production proportional to the expected increase in population (20 % by 2030) in order to maintain self-sufficiency at the present level. This is the background for the interdisciplinary project AGROPRO "Agronomy for increased food production - Challenges and solutions" (2013 - 2017)" financed by the Norwegian research council. A mail goal is seeking possibilities for improvements in agronomic practices for increased and sustainable food production and to identify drivers and challenges for their implementation. Are the key to higher yields hidden in the soil? The paper present an overview of the research activities in the project and some results of the improvements of soil quality to minimize yield gap in cereal and forage production. Detailed new soil maps provide soil information on field scale of soil quality and the suitability for growing different crops like cereal production or vegetables. The detailed soil information is also beeing used for development and adaptation of the planning tool «Terranimo» to reduce risk of soil compaction.The farmer get available soil information for each field, provide information about the maschinery in use- tractors and equipment, tyres, pressure. The decision tool evaluate when the soil is suitable for tillage, calculate the risk of compaction for dry, moist and wet soil. New research data for compaction on Norwegian clay and silt soil are included. Climate change with wetter conditions gives challenges for growing cereals. The project is testing genetic variation in cereals for tolerance to water logging and soil compaction. Several hundred different varieties for barley, oat and wheat are being waterlogged and resulting effects studied, also illustrating the need and benefit of cooperation between soil science and plant science (plant physiology). Field studies of functional root depth and root development is performed for studies of nutrient use efficiency of nitrogen and phosporus. Isotopic studies (15N) and DGT(diffuse gradients in thin films) are performed in long term experiments. Different rooting depths are studied in relation to effect of cutting regime of grasland, trafficking. The project perform new measurements of (N2O) emissions from long term cropping system experiments with different crop rotations, cultivation practice and fertilizing strategy. This can give better understanding of agronomic practices, nitrogen use efficiency and (N2O) emissions. The environmental effects of agricultural production is also dependent on the microbiological soil conditions.

Controlled low strength materials (CLSM), reported by ACI Committee 229

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

Rajendran, N.

1997-07-01

Controlled low-strength material (CLSM) is a self-compacted, cementitious material used primarily as a backfill in lieu of compacted fill. Many terms are currently used to describe this material including flowable fill, unshrinkable fill, controlled density fill, flowable mortar, flowable fly ash, fly ash slurry, plastic soil-cement, soil-cement slurry, K-Krete and other various names. This report contains information on applications, material properties, mix proportioning, construction and quality-control procedures. This report`s intent is to provide basic information on CLSM technology, with emphasis on CLSM material characteristics and advantages over conventional compacted fill. Applications include backfills, structural fills, insulating and isolation fills, pavementmore » bases, conduit bedding, erosion control, void filling, and radioactive waste management.« less

Compact, Lightweight Dual-Frequency Microstrip Antenna Feed for Future Soil Moisture and Sea Surface Salinity Missions

NASA Technical Reports Server (NTRS)

Yueh, Simon; Wilson, William J.; Njoku, Eni; Dinardo, Steve; Hunter, Don; Rahmat-Samii, Yahya; Kona, Keerti S.; Manteghi, Majid

2006-01-01

The development of a compact, lightweight, dual-frequency antenna feed for future soil moisture and sea surface salinity (SSS) missions is described. The design is based on the microstrip stacked-patch array (MSPA) to be used to feed a large lightweight deployable rotating mesh antenna for spaceborne L-band (approx.1 GHz) passive and active sensing systems. The design features will also enable applications to airborne soil moisture and salinity remote sensing sensors operating on small aircrafts. This paper describes the design of stacked patch elements and 16-element array configuration. The results from the return loss, antenna pattern measurements and sky tests are also described.

A Refined Sample of Lyman Excess H II Regions

NASA Astrophysics Data System (ADS)

Marshall, Brandon; Kerton, C. R.

2018-05-01

A large number (67) of the compact/ultra-compact H II regions identified in the CORNISH catalogue were determined to be powered by a Lyman continuum flux in excess of what was expected given their corresponding luminosity. In this study we attempt to reasonably explain away this Lyman excess phenomenon in as many of the 67 H II regions as possible through a variety of observational and astrophysical means including new luminosity estimates, new Herschel photometry, new distance determinations, the use of different models for dust and ionized gas covering factors, and the use of different stellar calibrations. This phenomenon has been observed before; however, the objects shown to exhibit this behavior in the literature have decidedly different physical properties than the regions in our sample, and thus the origin of the excess is not the same. We find that the excess can be reproduced using OB stellar atmosphere models that have been slightly modified in the extreme ultraviolet. Though the exact mechanism producing the excess is still uncertain, we do find that a scaled up magnetospheric accretion model, often used to explain similar emission from T Tauri stars, is unable to match our observations. Our results suggest that the Lyman excess may be associated with younger H II regions, and that it is more commonly found in early B-type stars. Our refined sample of 24 Lyman excess H II regions provides an ideal sample for comparative studies with regular H II regions, and can act as the basis for the further detailed study of individual regions.

Process for forming coal compacts and product thereof

DOEpatents

Gunnink, Brett; Kanunar, Jayanth; Liang, Zhuoxiong

2002-01-01

A process for forming durable, mechanically strong compacts from coal particulates without use of a binder is disclosed. The process involves applying a compressive stress to a particulate feed comprising substantially water-saturated coal particles while the feed is heated to a final compaction temperature in excess of about 100.degree. C. The water present in the feed remains substantially in the liquid phase throughout the compact forming process. This is achieved by heating and compressing the particulate feed and cooling the formed compact at a pressure sufficient to prevent water present in the feed from boiling. The compacts produced by the process have a moisture content near their water saturation point. As a result, these compacts absorb little water and retain exceptional mechanical strength when immersed in high pressure water. The process can be used to form large, cylindrically-shaped compacts from coal particles (i.e., "coal logs") so that the coal can be transported in a hydraulic coal log pipeline.

Compost improves urban soil and water quality

USDA-ARS?s Scientific Manuscript database

Construction in urban zones compacts the soil, which hinders root growth and infiltration and may increase erosion, which may degrade water quality. The purpose of our study was to determine the whether planting prairie grasses and adding compost to urban soils can mitigate these concerns. We simula...

Comparison of five tillage systems in coastal plain soils for cotton production

USDA-ARS?s Scientific Manuscript database

Soil compaction management in the southeastern USA typically relies heavily on the practice of annual deep tillage. Strip tillage systems have shown considerable promise for reducing energy and labor requirements, equipment costs, soil erosion, and cotton plant damage from blowing sand. Replicated f...

The patterns and implications of diurnal variations in the d-excess of plant water, shallow soil water and air moisture

NASA Astrophysics Data System (ADS)

Zhao, L.; Wang, L.; Liu, X.; Xiao, H.; Ruan, Y.; Zhou, M.

2014-10-01

Deuterium excess (d-excess) of air moisture is traditionally considered a conservative tracer of oceanic evaporation conditions. Recent studies challenge this view and emphasize the importance of vegetation activity in controlling the dynamics of air moisture d-excess. However, direct field observations supporting the role of vegetation in d-excess variations are not well documented. In this study, we quantified the d-excess of air moisture, shallow soil water (5 and 10 cm) and plant water (leaf, root and xylem) of multiple dominant species at hourly intervals during three extensive field campaigns at two climatically different locations within the Heihe River basin, northwestern China. The ecosystems at the two locations range from forest to desert. The results showed that with the increase in temperature (T) and the decrease in relative humidity (RH), the δD-δ18O regression lines of leaf water, xylem water and shallow soil water deviated gradually from their corresponding local meteoric water line. There were significant differences in d-excess values between different water pools at all the study sites. The most positive d-excess values were found in air moisture (9.3‰) and the most negative d-excess values were found in leaf water (-85.6‰). The d-excess values of air moisture (dmoisture) and leaf water (dleaf) during the sunny days, and shallow soil water (dsoil) during the first sunny day after a rain event, showed strong diurnal patterns. There were significantly positive relationships between dleaf and RH and negative relationships between dmoisture and RH. The correlations of dleaf and dmoisture with T were opposite to their relationships with RH. In addition, we found opposite diurnal variations for dleaf and dmoisture during the sunny days, and for dsoil and dmoisture during the first sunny day after the rain event. The steady-state Craig-Gordon model captured the diurnal variations in dleaf, with small discrepancies in the magnitude. Overall, this study provides a comprehensive and high-resolution data set of d-excess of air moisture, leaf, root, xylem and soil water. Our results provide direct evidence that dmoisture of the surface air at continental locations can be significantly altered by local processes, especially plant transpiration during sunny days. The influence of shallow soil water on dmoisture is generally much smaller compared with that of plant transpiration, but the influence could be large on a sunny day right after rainfall events.

The temporal changes in saturated hydraulic conductivity of forest soils

NASA Astrophysics Data System (ADS)

Kornél Szegedi, Balázs

2015-04-01

I investigated the temporal variability of forest soils infiltration capacity through compaction. I performed the measurements of mine in The Botanical Garden of Sopron between 15.09.2014 - 15.10.2014. I performed the measurements in 50-50 cm areas those have been cleaned of vegetation, where I measured the bulk density and volume of soil hydraulic conductivity with Tension Disk Infiltrometer (TDI) in 3-3 repetitions. I took undisturbed 160 cm3 from the upper 5 cm layer of the cleaned soil surface for the bulk density measurements. Then I loosened the top 10-15 cm layer of the soil surface with spade. After the cultivation of the soil I measured the bulk density and volume of water conductivity also 3-3 repetitions. Later I performed the hydraulic conductivity (Ksat) using the TDI and bulk density measurements on undisturbed samples on a weekly basis in the study area. I illustrated the measured hydraulic conductivity and bulk density values as a function of cumulative rainfall by using simple graphical and statistical methods. The rate of the soil compaction pace was fast and smooth based on the change of the measured bulk density values. There was a steady downward trend in hydraulic conductivity parallel the compaction. The cultivation increased the hydraulic conductivity nearly fourfold compared to original, than decreased to half by 1 week. In the following the redeposition rate declined, but based on the literature data, almost 3-4 months enough to return the original state before cultivation of the soil hydraulic conductivity and bulk density values. This publication has been supported by AGRARKLIMA.2 VKSZ_12-1-2013-0034 project.

Biochar-enhanced composts reduce the potential leaching of nutrients and heavy metals and suppress plant-parasitic nematodes in excessively fertilized cucumber soils.

PubMed

Cao, Yune; Gao, Yanming; Qi, Yanbin; Li, Jianshe

2018-03-01

Excessive fertilization is a common agricultural practice that has largely reduced soil nutrient retention capacity and led to nutrient leaching in China. To reduce nutrient leaching, in this study, we evaluated the application of biochar, compost, and biochar-compost on soil properties, leaching water quality, and cucumber plant growth in soils with different nutrient levels. In general, the concentrations of nutrients and heavy metals in leaching water were higher under high-nutrient conditions than under low-nutrient conditions. Both biochar and compost efficiently enhanced soil cation exchange capacity (CEC), water holding capacity (WHC), and microbial biomass carbon (MBC), nitrogen (MBN), and phosphorus (MBP), reduced the potential leaching of nutrients and heavy metals, and improved plant growth. The efficiency of biochar and compost in soil CEC, WHC, MBC, MBN, and MBP and plant growth was enhanced when applied jointly. In addition, biochar and biochar-enhanced compost efficiently suppressed plant-parasitic nematode infestation in a soil with high levels of both N and P. Our results suggest that biochar-enhanced compost can reduce the potential environmental risks in excessively fertilized vegetable soils.

Behavior of nonplastic silty soils under cyclic loading.

PubMed

Ural, Nazile; Gunduz, Zeki

2014-01-01

The engineering behavior of nonplastic silts is more difficult to characterize than is the behavior of clay or sand. Especially, behavior of silty soils is important in view of the seismicity of several regions of alluvial deposits in the world, such as the United States, China, and Turkey. In several hazards substantial ground deformation, reduced bearing capacity, and liquefaction of silty soils have been attributed to excess pore pressure generation during dynamic loading. In this paper, an experimental study of the pore water pressure generation of silty soils was conducted by cyclic triaxial tests on samples of reconstituted soils by the slurry deposition method. In all tests silty samples which have different clay percentages were studied under different cyclic stress ratios. The results have showed that in soils having clay content equal to and less than 10%, the excess pore pressure ratio buildup was quicker with an increase in different cyclic stress ratios. When fine and clay content increases, excess pore water pressure decreases constant cyclic stress ratio in nonplastic silty soils. In addition, the applicability of the used criteria for the assessment of liquefaction susceptibility of fine grained soils is examined using laboratory test results.

Behavior of Nonplastic Silty Soils under Cyclic Loading

PubMed Central

Ural, Nazile; Gunduz, Zeki

2014-01-01

The engineering behavior of nonplastic silts is more difficult to characterize than is the behavior of clay or sand. Especially, behavior of silty soils is important in view of the seismicity of several regions of alluvial deposits in the world, such as the United States, China, and Turkey. In several hazards substantial ground deformation, reduced bearing capacity, and liquefaction of silty soils have been attributed to excess pore pressure generation during dynamic loading. In this paper, an experimental study of the pore water pressure generation of silty soils was conducted by cyclic triaxial tests on samples of reconstituted soils by the slurry deposition method. In all tests silty samples which have different clay percentages were studied under different cyclic stress ratios. The results have showed that in soils having clay content equal to and less than 10%, the excess pore pressure ratio buildup was quicker with an increase in different cyclic stress ratios. When fine and clay content increases, excess pore water pressure decreases constant cyclic stress ratio in nonplastic silty soils. In addition, the applicability of the used criteria for the assessment of liquefaction susceptibility of fine grained soils is examined using laboratory test results. PMID:24672343

75 FR 21577 - Rogue River-Siskiyou National Forest, Powers Ranger District, Coos County, OR; Eden Ridge Timber...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-26

... on soil, slope and hydrological concerns. New system road construction, reconstruction of... natural succession processes. The residual trees would have less competition for sunlight, water and soil... designed to: Minimize soil impacts (erosion, compaction and/or displacement); Minimize damage to residual...

Compaction-Based Deformable Terrain Model as an Interface for Real-Time Vehicle Dynamics Simulations

DTIC Science & Technology

2013-04-16

to vehicular loads, and the resulting visco-elastic-plastic stress/strain on the affected soil volume. Pedo transfer functions allow for the...resulting visco-elastic-plastic stress/strain on the affected soil volume. Pedo transfer functions allow for the calculation of the soil mechanics model

Sustaining aspen productivity in the Lake States

Treesearch

Douglas M. Stone

2001-01-01

Sustaining forest productivity requires maintaining soil productivity. Management activities that decrease soil porosity and remove organic matter can reduce productivity. We determined effects of three levels of organic matter removal (OMR) and soil compaction on aspen regeneration and growth following winter harvest of aspen-dominated stands in northern Minnesota,...

Soil analyses and evaluations at the impact dynamics research facility for two full-scale aircraft crash tests

NASA Technical Reports Server (NTRS)

Cheng, R. Y. K.

1977-01-01

The aircraft structural crash behavior and occupant survivability for aircraft crashes on a soil surface was studied. The results of placement, compaction, and maintenance of two soil test beds are presented. The crators formed by the aircraft after each test are described.

44 CFR 65.10 - Mapping of areas protected by levee systems.

Code of Federal Regulations, 2013 CFR

2013-10-01

... compaction, penetrations, other design factors affecting seepage (such as drainage layers), and other design..., compressibility of embankment soils, compressibility of foundation soils, age of the levee system, and... described in the COE manual, “Soil Mechanics Design—Settlement Analysis” (EM 1100-2-1904) must be submitted...

44 CFR 65.10 - Mapping of areas protected by levee systems.

Code of Federal Regulations, 2011 CFR

2011-10-01

... compaction, penetrations, other design factors affecting seepage (such as drainage layers), and other design..., compressibility of embankment soils, compressibility of foundation soils, age of the levee system, and... described in the COE manual, “Soil Mechanics Design—Settlement Analysis” (EM 1100-2-1904) must be submitted...

44 CFR 65.10 - Mapping of areas protected by levee systems.

Code of Federal Regulations, 2014 CFR

2014-10-01

... compaction, penetrations, other design factors affecting seepage (such as drainage layers), and other design..., compressibility of embankment soils, compressibility of foundation soils, age of the levee system, and... described in the COE manual, “Soil Mechanics Design—Settlement Analysis” (EM 1100-2-1904) must be submitted...

44 CFR 65.10 - Mapping of areas protected by levee systems.

Code of Federal Regulations, 2012 CFR

2012-10-01

... compaction, penetrations, other design factors affecting seepage (such as drainage layers), and other design..., compressibility of embankment soils, compressibility of foundation soils, age of the levee system, and... described in the COE manual, “Soil Mechanics Design—Settlement Analysis” (EM 1100-2-1904) must be submitted...

Effects of biochar on hydraulic conductivity of compacted kaolin clay.

PubMed

Wong, James Tsz Fung; Chen, Zhongkui; Wong, Annie Yan Yan; Ng, Charles Wang Wai; Wong, Ming Hung

2018-03-01

Compacted clay is widely used as capillary barriers in landfill final cover system. Recently, biochar amended clay (BAC) has been proposed as a sustainable alternative cover material. However, the effects of biochar on saturated hydraulic conductivity (k sat ) of clay with high degree of compaction is not yet understood. The present study aims to investigate the effects of biochar on k sat of compacted kaolin clay. Soil specimens were prepared by amending kaolin clay with biochar derived from peanut-shell at 0, 5 and 20% (w/w). The k sat of soil specimens was measured using a flexible water permeameter. The effects of biochar on the microstructure of the compacted clay was also investigated using MIP. Adding 5% and 20% of biochar increased the k sat of compacted kaolin clay from 1.2 × 10 -9 to 2.1 × 10 -9 and 1.3 × 10 -8 ms -1 , respectively. The increase in k sat of clay was due to the shift in pore size distribution of compacted biochar-amended clay (BAC). MIP results revealed that adding 20% of biochar shifted the dominant pore diameter of clay from 0.01-0.1 μm (meso- and macropores) to 0.1-4 μm (macropores). Results reported in this communication revealed that biochar application increased the k sat of compacted clay, and the increment was positively correlated to the biochar percentage. Copyright © 2017 Elsevier Ltd. All rights reserved.

Reducing environmental risk of excessively fertilized soils and improving cucumber growth by Caragana microphylla-straw compost application in long-term continuous cropping systems.

PubMed

Tian, Yongqiang; Wang, Qing; Zhang, Weihua; Gao, Lihong

2016-02-15

Continuous cropping is a common agricultural practice in the word. In China, farmers often apply excessive fertilizers to fields in an attempt to maintain yields in continuous cropping systems. However, this practice often results in high nutrient concentrations in soils, nutrient pollution in leaching water and more crop disease. Here, we investigated 8 different soils from continuously cropped cucumbers in Northern China that grouped into those with extremely high nutrient levels (EHNL) and those with lower nutrient levels (LNL). All soils were treated with Caragana microphylla-straw (CMS) compost addition, and then were used to measure soil physiochemical and microbial properties, leaching water quality, plant root growth and cucumber fruit yield. In general, the EHNL-soil showed higher nitrate, phosphorus and potassium concentrations in the leaching water compared to the LNL-soil. However, the CMS compost application increased soil nutrient and water holding capacities, total microbial biomass (bacteria and fungi), root length, plant biomass and fruit yields, but decreased nutrient concentrations in the leaching water from the EHNL-soil. In addition, the CMS compost decreased the number of Fusarium oxysporum f. sp. cucumerinum in soils with very high concentration of mineral nitrogen. Our results infer that CMS compost application was an effective method for reducing environmental risk of excessively fertilized soils. Copyright © 2015 Elsevier B.V. All rights reserved.

Microbiological assessment of the application of quicklime and limestone as a measure to stabilize the structure of compaction-prone soils

NASA Astrophysics Data System (ADS)

Deltedesco, Evi; Bauer, Lisa-Maria; Unterfrauner, Hans; Peticzka, Robert; Zehetner, Franz; Keiblinger, Katharina Maria

2014-05-01

Compaction of soils is caused by increasing mechanization of agriculture and forestry, construction of pipelines, surface mining and land recultivation. This results in degradation of aggregate stability and a decrease of pore space, esp. of macropores. It further impairs the water- and air permeability, and restricts the habitat of soil organisms. A promising approach to stabilize the structure and improve the permeability of soils is the addition of polyvalent ions like Ca2+ which can be added in form of quicklime (CaO) and limestone (CaCO3). In this study, we conducted a greenhouse pot experiment using these two different sources of calcium ions in order to evaluate their effect over time on physical properties and soil microbiology. We sampled silty and clayey soils from three different locations in Austria and incubated them with and without the liming materials (application 12.5 g) for 3 months in four replicates. In order to assess short-term and medium-term effects, soil samples were taken 2 days, 1 month and 3 months after application of quicklime and limestone, respectively. For these samples, we determined pH, bulk density, aggregate stability and water retention characteristics. Further, we measured microbiological parameters, such as potential enzyme activities (cellulase, phosphatase, chitinase, protease, phenoloxidase and peroxidase activity), PLFAs, microbial biomass carbon and nitrogen, dissolved organic carbon and nitrogen, nitrate nitrogen and ammonium nitrogen. In contrast to limestone, quicklime significantly improved soil aggregate stability in all tested soils only 2 days after application. Initially, soil pH was strongly increased by quicklime; however, after the second sampling (one month) the pH values of all tested soils returned to levels comparable to the soils treated with limestone. Our preliminary microbiological results show an immediate inhibition effect of quicklime on most potential hydrolytic enzyme activities and an increase in oxidative enzyme activities. These effects seem to be less pronounced in the medium term. In summary our results indicate, that the application of quicklime is a feasible measure for immediate stabilization of the structure of compaction-prone soils, showing only short-term impact on most microbial parameters.

Properties of soil in the San Fernando hydraulic fill dams

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

Lee, K.L.

1975-08-01

Results are presented of extensive field and laboratory tests on soils from two old hydraulic fill dams that were damaged during the Feb. 9, 1971, San Fernando earthquake. The data include standard penetration, absolute and relative compaction, relative density, static strength, and cyclic triaxial test results for both the hydraulic fill silty sand and the natural silty and gravelly sand alluvium. The relative densities of the hydraulic fills ranged from about 51 to 58 percent and the relative compaction ranged from about 85 to 92 percent of Modified AASHO maximum density. The relative density of the alluvium was about 65more » to 70 percent. Other properties were consistent with previously published data from other similar soils at similar densities.« less

Effects of leachate on geotechnical characteristics of sandy clay soil

NASA Astrophysics Data System (ADS)

Harun, N. S.; Ali, Z. Rahman; Rahim, A. S.; Lihan, T.; Idris, R. M. W.

2013-11-01

Leachate is a hazardous liquid that poses negative impacts if leaks out into environments such as soil and ground water systems. The impact of leachate on the downgraded quality in terms of chemical characteristic is more concern rather than the physical or mechanical aspect. The effect of leachate on mechanical behaviour of contaminated soil is not well established and should be investigated. This paper presents the preliminary results of the effects of leachate on the Atterberg limit, compaction and shear strength of leachate-contaminated soil. The contaminated soil samples were prepared by mixing the leachate at ratiosbetween 0% and 20% leachate contents with soil samples. Base soil used was residual soil originated from granitic rock and classified as sandy clay soil (CS). Its specific gravity ranged between 2.5 and 2.64 with clay minerals of kaolinite, muscovite and quartz. The field strength of the studied soil ranged between 156 and 207 kN/m2. The effects of leachate on the Atterberg limit clearly indicated by the decrease in liquid and plastic limit values with the increase in the leachate content. Compaction tests on leachate-contaminated soil caused the dropped in maximum dry density, ρdry and increased in optimum moisture content, wopt when the amount of leachate was increased between 0% and 20%. The results suggested that leachate contamination capable to modify some geotechnical properties of the studied residual soils.

The Role of Interdisciplinary Earth Science in the Assessment of Regional Land Subsidence Hazards: Toward Sustainable Management of Global Land and Subsurface-Fluid Resources

NASA Astrophysics Data System (ADS)

Galloway, D. L.

2012-12-01

Land-level lowering or land subsidence is a consequence of many local- and regional-scale physical, chemical or biologic processes affecting soils and geologic materials. The principal processes can be natural or anthropogenic, and include consolidation or compaction, karst or pseudokarst, hydrocompaction of collapsible soils, mining, oxidation of organic soils, erosive piping, tectonism, and volcanism. In terms of affected area, there are two principal regional-scale anthropogenic processes—compaction of compressible subsurface materials owing to the extraction of subsurface fluids (principally groundwater, oil and gas) and oxidation and compaction accompanying drainage of organic soils—which cause significant hazards related to flooding and infrastructure damage that are amenable to resource management measures. The importance of even small magnitude (< 10 mm/yr) subsidence rates in coastal areas is amplified by its contribution to relative sea-level rise compared to estimated rates of rising eustatic sea levels (2-3 mm/yr) attributed to global climate change. Multi- or interdisciplinary [scientific] studies, including those focused on geodetic, geologic, geophysical, hydrologic, hydrogeologic, geomechanical, geochemical, and biologic factors, improve understanding of these subsidence processes. Examples include geodetic measurement and analysis techniques, such as Global Positioning System (GPS), Light Detection and Ranging (LiDAR) and Interferometric Synthetic Aperture Radar (InSAR), which have advanced our capabilities to detect, measure and monitor land-surface motion at multiple scales. Improved means for simulating aquifer-system and hydrocarbon-reservoir deformation, and the oxidation and compaction of organic soils are leading to refined predictive capabilities. The role of interdisciplinary earth science in improving the characterization of land subsidence attributed to subsurface fluid withdrawals and the oxidation and compaction of organic soils is examined. How these improved capabilities are translating into improved sustainable management of regional land and water resources in a few select areas worldwide are presented. The importance of incorporating these improved capabilities in coherent resource management strategies to control the depletion of resources and attendant hazards also are discussed.

Differential settlement of a geosynthetic reinforced soil abutment : full-scale investigation.

DOT National Transportation Integrated Search

2015-05-01

The Geosynthetic Reinforced Soil Integrated Bridge System (GRS-IBS) uses alternating layers of closely spaced : geosynthetic reinforcement and well-compacted granular fill to support the bridge superstructure and form an integrated roadway : approach...

Effect of roller/crimper designs in terminating rye cover crop in small-scale conservation systems

USDA-ARS?s Scientific Manuscript database

In recent years, use of cover crops in no-till organic production systems has steadily increased. When cover crops are terminated at an appropriate growth stage, the unincorporated residue mulch protects the soil from erosion, runoff, soil compaction, and weed pressure, and conserves soil water. In ...

78 FR 9029 - Nez Perce-Clearwater National Forests; ID; Clear Creek Integrated Restoration Project

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-07

... Nez Perce Forest Plan, and would adopt the Regional soils standard for the Clear Creek Integrated... transportation needs. Site-specifically amend the Nez Perce Forest Plan (1987) to adopt the Region 1 soil standard of 15% for detrimentally compacted, displaced, or puddled soils for the Clear Creek Integrated...

Soil response to skidder trafficking and slash application

Treesearch

Brian M. Parkhurst; W. Michael Aust; M. Chad Bolding; Scott M. Barrett; Emily A. Carter

2018-01-01

Ground-based timber harvesting systems are common in the United States. Harvesting machinery can negatively influence soils by increasing erosion and decreasing site productivity. Skid trails can become compacted and erosive. Slash applications to skid trails are effective for erosion control, yet few investigations have examined effects of slash on soil physical...

Roles of biology, chemistry, and physics in soil macroaggregate formation and stabilization

USDA-ARS?s Scientific Manuscript database

Soil functions or ecosystem services depend on the distribution of macro- (= 0.25 mm) and micro- (< 0.25 mm) aggregates and open space between aggregates. It is the arrangement of the aggregates and pore space which allows air and water movement in and out of soil; reduces compaction; and stimulates...

40 CFR 264.301 - Design and operating requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... subsurface soil or ground water or surface water at anytime during the active life (including the closure... of the liners and soils present between the landfill and ground water or surface water; and (4) All... were to occur. The lower component must be constructed of at least 3 feet (91 cm) of compacted soil...

40 CFR 264.301 - Design and operating requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... subsurface soil or ground water or surface water at anytime during the active life (including the closure... of the liners and soils present between the landfill and ground water or surface water; and (4) All... were to occur. The lower component must be constructed of at least 3 feet (91 cm) of compacted soil...

40 CFR 264.301 - Design and operating requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... subsurface soil or ground water or surface water at anytime during the active life (including the closure... of the liners and soils present between the landfill and ground water or surface water; and (4) All... were to occur. The lower component must be constructed of at least 3 feet (91 cm) of compacted soil...

Compacted dimensions and singular plasmonic surfaces

NASA Astrophysics Data System (ADS)

Pendry, J. B.; Huidobro, Paloma Arroyo; Luo, Yu; Galiffi, Emanuele

2017-11-01

In advanced field theories, there can be more than four dimensions to space, the excess dimensions described as compacted and unobservable on everyday length scales. We report a simple model, unconnected to field theory, for a compacted dimension realized in a metallic metasurface periodically structured in the form of a grating comprising a series of singularities. An extra dimension of the grating is hidden, and the surface plasmon excitations, though localized at the surface, are characterized by three wave vectors rather than the two of typical two-dimensional metal grating. We propose an experimental realization in a doped graphene layer.

Ponderosa pine growth response to soil strength in the volcanic ash soils of central Oregon.

Treesearch

R.T. Parker; D.A. Maguire; D.D. Marshall; P. Cochran

2007-01-01

Mechanical harvesting and associated logging activities have the capacity to compact soil across large portions of harvest units. Two thinning treatments (felled only versus felled and skidded) in 70- to 80-year-old ponderosa pine stands were replicated at three sites with volcanic soils in central Oregon. Growth in diameter, height, and volume of residual trees were...

The North American long-term soil productivity experiment: findings from the first decade of research

Treesearch

Robert F. Powers; D. Andrew Scott; Felipe g. Sanchez; Richard A. Voldseth; Deborah Page-Dumroese; John D. Elioff; Douglas M. Stone

2005-01-01

First decade findings on the impacts of organic matter removal and soil compaction are reported for the 26 oldest installations in the nation-wide network of long-term soil productivity sites. Complete removal of surface organic matter led to declines in soil C concentration to 20 cm depth and to reduced nutrient availability. The effect is attributed mainly to the...

Correlations and spatial variability of soil physical properties in harvested piedmont forests

Treesearch

Emily A. Carter; J.N. Shaw

2002-01-01

Soil response to timber harvest trafficking was similar for eroded soils in two locations of the Piedmont of Alabama. Pre-harvest and post-harvest data indicated compaction to be present to a depth of 40 cm as indicated by cone index measurements, with the most significant changes occurring in the upper 20 cm. The degree of spatial dependence differed among soil...

Biochar can be used to capture essential nutrients from dairy wastewater and improve soil physico-chemical properties

NASA Astrophysics Data System (ADS)

Ghezzehei, T. A.; Sarkhot, D. V.; Berhe, A. A.

2014-09-01

Recently, the potential for biochar use to recapture excess nutrients from dairy wastewater has been a focus of a growing number of studies. It is suggested that biochar produced from locally available excess biomass can be important in reducing release of excess nutrient elements from agricultural runoff, improving soil productivity, and long-term carbon (C) sequestration. Here we present a review of a new approach that is showing promise for the use of biochar for nutrient capture. Using batch sorption experiments, it has been shown that biochar can adsorb up to 20-43% of ammonium and 19-65% of the phosphate in flushed dairy manure in 24 h. These results suggest a potential of biochar for recovering essential nutrients from dairy wastewater and improving soil fertility if the enriched biochar is returned to soil. Based on the sorption capacity of 2.86 and 0.23 mg ammonium and phosphate, respectively, per gram of biochar and 10-50% utilization of available excess biomass, in the state of California (US) alone, 11 440 to 57 200 tonnes of ammonium-N and 920-4600 tonnes of phosphate can be captured from dairy waste each year while at the same time disposing up to 8-40 million tons of excess biomass.

Soil properties affecting wheat yields following drilling-fluid application.

PubMed

Bauder, T A; Barbarick, K A; Ippolito, J A; Shanahan, J F; Ayers, P D

2005-01-01

Oil and gas drilling operations use drilling fluids (mud) to lubricate the drill bit and stem, transport formation cuttings to the surface, and seal off porous geologic formations. Following completion of the well, waste drilling fluid is often applied to cropland. We studied potential changes in soil compaction as indicated by cone penetration resistance, pH, electrical conductivity (EC(e)), sodium adsorption ratio (SAR), extractable soil and total straw and grain trace metal and nutrient concentrations, and winter wheat (Triticum aestivum L. 'TAM 107') grain yield following water-based, bentonitic drilling-fluid application (0-94 Mg ha(-1)) to field test plots. Three methods of application (normal, splash-plate, and spreader-bar) were used to study compaction effects. We measured increasing SAR, EC(e), and pH with drilling-fluid rates, but not to levels detrimental to crop production. Field measurements revealed significantly higher compaction within areas affected by truck travel, but also not enough to affect crop yield. In three of four site years, neither drilling-fluid rate nor application method affected grain yield. Extractions representing plant availability and plant analyses results indicated that drilling fluid did not significantly increase most trace elements or nutrient concentrations. These results support land application of water-based bentonitic drilling fluids as an acceptable practice on well-drained soils using controlled rates.

Analysis of physical parameters related with water infiltration in tropical soils located in edges forest in urban areas

NASA Astrophysics Data System (ADS)

Márcia Longo, Regina; Cunha, Jessica C. M.; Lammoglia, Rafaella; Mendes, Deborah R.; Mungilioli, Sarah S.; Damame, Desiree B.; Demamboro, Antônio C.; Bettine, Sueli C.; Ribeiro, Admilson I.; Fengler, Felipe H.

2015-04-01

A very important factor for water infiltration into the soil in urban forest systems and suffering constant anthropogenic pressures is the analysis of soil compaction where these forests are or will be established. In this context, this work aimed to promote studies on physical parameters related to distribution of pores, compaction and soil biological activity in forest remnants border areas located in urban watersheds in Campinas / SP - Brazil. The Forest of Santa Genebra (22°49'45 "S and 47°06'33" W) has an average altitude of 680m and tropical climate of altitude, has an area of 251 ha and a nine kilometer perimeter. It constitutes 85% of Semideciduos forests and 15% swamp forest. Due to its location close to urban centers, roads and agricultural areas under direct influence of the anthropic means. For the present study analyzes were performed: particle size, soil density, porosity, matters organic, of biopores, and root distribution (primary, secondary and tertiary) and seedlings in 40 points on the perimeter of the forest equidistant 200m remaining edge. The analysis of the results allowed us to observe that areas suffer direct influence of human activities surrounding. With the results set correlations between the different parameters in order to allow a better understanding of the dynamics of water infiltration into the soil under these conditions and the quantity of tertiary roots, biopores and soil density were the best indicator of environmental quality as suffer direct influence of the surrounding areas, especially those near the most urbanized regions. In general, it can be observed that human activities such as deforestation and vehicle traffic, animals and people, promoted soil compaction and consequent changes in water infiltration into the soil in areas of edges of this remnant of these consequences affect direct numerous parameters that directly influence the dynamics of an ecosystem restoration that is now significantly affected by the occupation of their surroundings.

Differential settlement of a geosynthetic reinforced soil abutment : full-scale investigation : summary report.

DOT National Transportation Integrated Search

2015-05-01

The Geosynthetic Reinforced Soil Integrated Bridge System (GRS-IBS) uses alternating layers of closely spaced : geosynthetic reinforcement and well-compacted granular fill to support the bridge superstructure and form an integrated roadway : approach...

Long‐Term Monitoring of a Geosynthetic Reinforced Soil Integrated Bridge System (GRS‐IBS)

DOT National Transportation Integrated Search

2017-11-01

The geosynthetic reinforced soil integrated bridge system (GRS-IBS) is an innovative alternative to conventional bridge technology that utilizes closely spaced layers of geosynthetic reinforcement and compacted granular fill material to provide direc...

Investigating Forest Soil Disturbance with Different Timber Harvesting Operations in South Korea

NASA Astrophysics Data System (ADS)

Im, Sangjun; Lee, Eunjai; Eu, Song; Han, Sang-Kyun

2017-04-01

Forest operation such as timber harvesting can influence to forest environment by displacing soil particles, compacting surface layers, and destroying soil structures. This results in increased surface runoff and associated soil erosion during rainy season, due to soil disturbance. The extent of soil disturbance depends on the skidding/yarding method, types of machine used, and soil types. In South Korea, cut-to-length (CTL) operation is traditionally used by excavator with grapple in most areas. Recently, whole-tree (WT) harvesting system by swing yarder has gained considerable attention as an alternative traditional extraction method. The objectives of this study were to describe the effects of two different harvesting methods (CTL and WT) on soil disturbance and soil physical properties. After the CTL observation, we found that severe disturbed soils and compacted area were more than WT. Rutting was influenced more than 50% of the deep disturbance classes by the uphill climbing and downhill extraction method, while exposing bare soil was most disturbance in WT operation. Soil physical properties were influenced considerably by the number of excavator passes and slash residual classes in both units. The results from the study would be useful for understanding soil disturbance influence by timber harvesting in Korea. But, more detailed observations are needed to accurately estimate erosion rates and sediment delivery associated with forest management and operation. Acknowledgements. This study was carried out with the support of 'R&D Program for Forestry Technology (Project No. S211316L020110)' provided by Korea Forest Service.

Impacts of harvesting and postharvest treatments on soil bulk density, soil strength, and ealry growth of Pinus taeda in the Gulf Coastal Plain: a long-term soil productivity affiliated study

Treesearch

Mason C. Carter; Thomas J. Dean; Ziyin Wang; Ray A. Newbold

2006-01-01

At four sites in the Gulf Coastal Plain, mechanical whole-tree harvesting (MWT) removed from biomass and nutrients than hand-fell bole-only harvesting (HFBO). Soil compaction and loblolly pine (Pinus taeda L.) regeneration growth varied among sites. At one location, MWT increased soil bulk density by 0.1 Mgm-3, from 1.14 to 1....

Simulating root-induced rhizosphere deformation and its effect on water flow

NASA Astrophysics Data System (ADS)

Aravena, J. E.; Ruiz, S.; Mandava, A.; Regentova, E. E.; Ghezzehei, T.; Berli, M.; Tyler, S. W.

2011-12-01

Soil structure in the rhizosphere is influenced by root activities, such as mucilage production, microbial activity and root growth. Root growth alters soil structure by moving and deforming soil aggregates, affecting water and nutrient flow from the bulk soil to the root surface. In this study, we utilized synchrotron X-ray micro-tomography (XMT) and finite element analysis to quantify the effect of root-induced compaction on water flow through the rhizosphere to the root surface. In a first step, finite element meshes of structured soil around the root were created by processing rhizosphere XMT images. Then, soil deformation by root expansion was simulated using COMSOL Multiphysics° (Version 4.2) considering the soil an elasto-plastic porous material. Finally, fluid flow simulations were carried out on the deformed mesh to quantify the effect of root-induced compaction on water flow to the root surface. We found a 31% increase in water flow from the bulk soil to the root due to a 56% increase in root diameter. Simulations also show that the increase of root-soil contact area was the dominating factor with respect to the calculated increase in water flow. Increase of inter-aggregate contacts in size and number were observed within a couple of root diameters away from the root surface. But their influence on water flow was, in this case, rather limited compared to the immediate soil-root contact.

Response of Soil Bulk Density and Mineral Nitrogen to Harvesting and Cultural Treatments

Treesearch

Minyi Zhou; Mason C. Carter; Thomas J. Dean

1998-01-01

The interactive effects of harvest intensity, site preparation, and fertilization on soil compaction and nitrogen mineralization were examined in a loblolly pine (Pinus taeda L.) stand growing on a sandy, well-drained soil in eastern Texas. The experimental design was 2 by 2 by 2 factorial, consisting of two harvesting treatments (mechanical whole-...

Soil productivity and harvest operations

Treesearch

Deborah Page-Dumroese

2007-01-01

Concern over changes in soil productivity due to forest management is often debated by forest managers and the public. One key element in the discussion is use of mechanized equipment (such as rubber-tired skidders, log forwarders, or tracked vehicles) to remove timber products from the forest. Part of the debate focuses on soil compaction, removal of nutrients when...

Hydrologic conditions controlling runoff generation immediately after wildfire

USGS Publications Warehouse

Ebel, Brian A.; Moody, John A.; Martin, Deborah A.

2012-01-01

We investigated the control of postwildfire runoff by physical and hydraulic properties of soil, hydrologic states, and an ash layer immediately following wildfire. The field site is within the area burned by the 2010 Fourmile Canyon Fire in Colorado, USA. Physical and hydraulic property characterization included ash thickness, particle size distribution, hydraulic conductivity, and soil water retention curves. Soil water content and matric potential were measured indirectly at several depths below the soil surface to document hydrologic states underneath the ash layer in the unsaturated zone, whereas precipitation and surface runoff were measured directly. Measurements of soil water content showed that almost no water infiltrated below the ash layer into the near-surface soil in the burned site at the storm time scale (i.e., minutes to hours). Runoff generation processes were controlled by and highly sensitive to ash thickness and ash hydraulic properties. The ash layer stored from 97% to 99% of rainfall, which was critical for reducing runoff amounts. The hydrologic response to two rain storms with different rainfall amounts, rainfall intensity, and durations, only ten days apart, indicated that runoff generation was predominantly by the saturation-excess mechanism perched at the ash-soil interface during the first storm and predominantly by the infiltration-excess mechanism at the ash surface during the second storm. Contributing area was not static for the two storms and was 4% (saturation excess) to 68% (infiltration excess) of the catchment area. Our results showed the importance of including hydrologic conditions and hydraulic properties of the ash layer in postwildfire runoff generation models.

Effects of organic matter removal, soil compaction, and vegetation control on 5-year seedling performance: a regional comparison of long-term soil productivity sites

Treesearch

Robert L. Fleming; Robert F. Powers; Neil W. Foster; J. Marty Kranabetter; D. Andrew Scott; Felix Jr. Ponder; Shannon Berch; William K. Chapman; Richard D. Kabzems; Kim H. Ludovici; David M. Morris; Deborah S. Page-Dumroese; Paul T. Sanborn; Felipe G. Sanchez; Douglas M. Stone; Allan E. Tiarks

2006-01-01

We examined fifth-year seedling response to soil disturbance and vegetation control at 42 experimental locations representing 25 replicated studies within the North American Long-Term Soil Productivity (LTSP) program. These studies share a common experimental design while encompassing a wide range of climate, site conditions, and forest types. Whole-tree harvest had...

TECHNICAL GUIDANCE DOCUMENT: QUALITY ASSURANCE AND QUALITY CONTROL FOR WASTE CONTAINMENT FACILITIES

EPA Science Inventory

This Technical Guidance Document provides comprehensive guidance on procedures for quality assurance and quality control for waste containment facilities. he document includes a discussion of principles and concepts, compacted soil liners, soil drainage systems, geosynthetic drai...

TECHNICAL GUIDANCE DOCUMENT: QUALITY ASSURANCE AND QUALITY CONTROL FOR WASTE CONTAINMENT FACILITIES

EPA Science Inventory

This Technical Guidance Document provides comprehensive guidance on procedures for quality assurance and quality control for waste containment facilities. The document includes a discussion of principles and concepts, compacted soil liners, soil drainage systems, geosynthetic dr...

Influence of Random Inclusion of Coconut Fibres on the Short term Strength of Highly Compressible Clay

NASA Astrophysics Data System (ADS)

Ramani Sujatha, Evangelin; SaiSree, S.; Prabalini, C.; Aysha Farsana, Z.

2017-07-01

The choice of natural fibres for soil stabilization provides an economic, safe and eco-friendly alternative to improve the properties of soil. They are an important step forward toward sustainable development. An attempt was made to study the influence of the random addition of untreated coconut fibres on the short term strength of soil, its stress-strain behavior, compaction characteristics and index properties. The soil selected for the study is a highly compressible clay sample with a liquid limit of 52.5 % and plasticity index of 38 %. The soil has no organic content. The study reveals that the compaction curves tend to shift to the right side, indicating more plastic behavior with the addition of fibres. The addition of fibres also reorient the soil structure to a more dispersed fashion. A significant increase in the unconfined compressive strength is also observed. An increase of nearly 51 % in the unconfined compressive strength is observed at 0.75 % coir inclusion. The stress-strain behavior of the soil shows a shift toward more plastic behavior. The mode of failure of the soil specimen is by cracking and with fibre inclusion, length of the failure cracks is restrained as the fibre tends to hold the cracks together, resulting in shorter cracks, with significant bulging of the specimen at failure.

Surface disturbances: their role in accelerating desertification

USGS Publications Warehouse

Belnap, Jayne

1995-01-01

Maintaining soil stability and normal water and nutrient cycles in desert systems is critical to avoiding desertification. These particular ecosystem processes are threatened by trampling of livestock and people, and by off-road vehicle use. Soil compaction and disruption of cryptobiotic soil surfaces (composed of cyanobacteria, lichens, and mosses) can result in decreased water availability to vascular plants through decreased water infiltration and increased albedo with possible decreased precipitation. Surface disturbance may also cause accelerated soil loss through wind and water erosion and decreased diversity and abundance of soil biota. In addition, nutrient cycles can be altered through lowered nitrogen and carbon inputs and slowed decomposition of soil organic matter, resulting in lower nutrient levels in associated vascular plants. Some cold desert systems may be especially susceptible to these disruptions due to the paucity of surface-rooting vascular plants for soil stabilization, fewer nitrogen-fixing higher plants, and lower soil temperatures, which slow nutrient cycles. Desert soils may recover slowly from surface disturbances, resulting in increased vulnerability to desertification. Recovery from compaction and decreased soil stability is estimated to take several hundred years. Re-establishment rates for soil bacterial and fungal populations are not known. The nitrogen fixation capability of soil requires at least 50 years to recover. Recovery of crusts can be hampered by large amounts of moving sediment, and re-establishment can be extremely difficult in some areas. Given the sensitivity of these resources and slow recovery times, desertification threatens million of hectares of semiarid lands in the United States.

The Snow Must Go On: Ground Ice Encasement, Snow Compaction and Absence of Snow Differently Cause Soil Hypoxia, CO2 Accumulation and Tree Seedling Damage in Boreal Forest

PubMed Central

Vuosku, Jaana; Ovaskainen, Anu; Stark, Sari; Rautio, Pasi

2016-01-01

At high latitudes, the climate has warmed at twice the rate of the global average with most changes observed in autumn, winter and spring. Increasing winter temperatures and wide temperature fluctuations are leading to more frequent rain-on-snow events and freeze-thaw cycles causing snow compaction and formation of ice layers in the snowpack, thus creating ice encasement (IE). By decreasing the snowpack insulation capacity and restricting soil-atmosphere gas exchange, modification of the snow properties may lead to colder soil but also to hypoxia and accumulation of trace gases in the subnivean environment. To test the effects of these overwintering conditions changes on plant winter survival and growth, we established a snow manipulation experiment in a coniferous forest in Northern Finland with Norway spruce and Scots pine seedlings. In addition to ambient conditions and prevention of IE, we applied three snow manipulation levels: IE created by artificial rain-on-snow events, snow compaction and complete snow removal. Snow removal led to deeper soil frost during winter, but no clear effect of IE or snow compaction done in early winter was observed on soil temperature. Hypoxia and accumulation of CO2 were highest in the IE plots but, more importantly, the duration of CO2 concentration above 5% was 17 days in IE plots compared to 0 days in ambient plots. IE was the most damaging winter condition for both species, decreasing the proportion of healthy seedlings by 47% for spruce and 76% for pine compared to ambient conditions. Seedlings in all three treatments tended to grow less than seedlings in ambient conditions but only IE had a significant effect on spruce growth. Our results demonstrate a negative impact of winter climate change on boreal forest regeneration and productivity. Changing snow conditions may thus partially mitigate the positive effect of increasing growing season temperatures on boreal forest productivity. PMID:27254100

The Snow Must Go On: Ground Ice Encasement, Snow Compaction and Absence of Snow Differently Cause Soil Hypoxia, CO2 Accumulation and Tree Seedling Damage in Boreal Forest.

PubMed

Martz, Françoise; Vuosku, Jaana; Ovaskainen, Anu; Stark, Sari; Rautio, Pasi

2016-01-01

At high latitudes, the climate has warmed at twice the rate of the global average with most changes observed in autumn, winter and spring. Increasing winter temperatures and wide temperature fluctuations are leading to more frequent rain-on-snow events and freeze-thaw cycles causing snow compaction and formation of ice layers in the snowpack, thus creating ice encasement (IE). By decreasing the snowpack insulation capacity and restricting soil-atmosphere gas exchange, modification of the snow properties may lead to colder soil but also to hypoxia and accumulation of trace gases in the subnivean environment. To test the effects of these overwintering conditions changes on plant winter survival and growth, we established a snow manipulation experiment in a coniferous forest in Northern Finland with Norway spruce and Scots pine seedlings. In addition to ambient conditions and prevention of IE, we applied three snow manipulation levels: IE created by artificial rain-on-snow events, snow compaction and complete snow removal. Snow removal led to deeper soil frost during winter, but no clear effect of IE or snow compaction done in early winter was observed on soil temperature. Hypoxia and accumulation of CO2 were highest in the IE plots but, more importantly, the duration of CO2 concentration above 5% was 17 days in IE plots compared to 0 days in ambient plots. IE was the most damaging winter condition for both species, decreasing the proportion of healthy seedlings by 47% for spruce and 76% for pine compared to ambient conditions. Seedlings in all three treatments tended to grow less than seedlings in ambient conditions but only IE had a significant effect on spruce growth. Our results demonstrate a negative impact of winter climate change on boreal forest regeneration and productivity. Changing snow conditions may thus partially mitigate the positive effect of increasing growing season temperatures on boreal forest productivity.

Predictive modeling of freezing and thawing of frost-susceptible soils.

DOT National Transportation Integrated Search

2015-09-01

Frost depth is an essential factor in design of various transportation infrastructures. In frost : susceptible soils, as soils freezes, water migrates through the soil voids below the freezing line : towards the freezing front and causes excessive he...

Sediment and solute transport in a mountainous watershed in Valle del Cauca, Colombia

NASA Astrophysics Data System (ADS)

Guzman, Christian; Hoyos Villada, Fanny; Morales Vargas, Amalia; Rivera, Baudelino; Da Silva, Mayesse; Moreno Padilla, Pedro; Steenhuis, Tammo

2015-04-01

Sediment samples and solute concentrations were measured from the La Vega micro watershed in the southwestern region of the Colombian Andes. A main goal of this study was to improve prediction of soil surface and soil nutrient changes, based on field measurements, within small basin of the Aguaclara watershed network receiving different types of conservation measures. Two modeling approaches for stream discharge and sediment transport predictions were used with one of these based on infiltration-excess and the other on saturation-excess runoff. These streams are a part of a recent initiative from a water fund established by Asobolo, Asocaña, and Cenicaña in collaboration with the Natural Capital Project to improve conservation efforts and monitor their effects. On-site soil depth changes, groundwater depth measurements, and soil nutrient concentrations were also monitored to provide more information about changes within this mountainous watershed during one part of the yearly rainy season. This information is being coupled closely with the outlet sediment concentration and solute concentration patterns to discern correlations between scales. Lateral transects in the upper, middle, and lower part of the hillsides in the La Vega micro watershed showed differences in soil nutrient status and soil surface depth changes. The model based on saturation-excess, semi-distributed hydrology was able to reproduce discharge and sediment transport rates as well as the initially used infiltration excess model indicating available options for comparison of conservation changes in the future.

Numerically Modeling the Erosion of Lunar Soil by Rocket Exhaust Plumes

NASA Technical Reports Server (NTRS)

2008-01-01

In preparation for the Apollo program, Leonard Roberts of the NASA Langley Research Center developed a remarkable analytical theory that predicts the blowing of lunar soil and dust beneath a rocket exhaust plume. Roberts assumed that the erosion rate was determined by the excess shear stress in the gas (the amount of shear stress greater than what causes grains to roll). The acceleration of particles to their final velocity in the gas consumes a portion of the shear stress. The erosion rate continues to increase until the excess shear stress is exactly consumed, thus determining the erosion rate. Roberts calculated the largest and smallest particles that could be eroded based on forces at the particle scale, but the erosion rate equation assumed that only one particle size existed in the soil. He assumed that particle ejection angles were determined entirely by the shape of the terrain, which acts like a ballistic ramp, with the particle aerodynamics being negligible. The predicted erosion rate and the upper limit of particle size appeared to be within an order of magnitude of small-scale terrestrial experiments but could not be tested more quantitatively at the time. The lower limit of particle size and the predictions of ejection angle were not tested. We observed in the Apollo landing videos that the ejection angles of particles streaming out from individual craters were time-varying and correlated to the Lunar Module thrust, thus implying that particle aerodynamics dominate. We modified Roberts theory in two ways. First, we used ad hoc the ejection angles measured in the Apollo landing videos, in lieu of developing a more sophisticated method. Second, we integrated Roberts equations over the lunar-particle size distribution and obtained a compact expression that could be implemented in a numerical code. We also added a material damage model that predicts the number and size of divots which the impinging particles will cause in hardware surrounding the landing rocket. Then, we performed a long-range ballistics analysis for the ejected particulates.

Physical and Social Impacts on Hydrologic Properties of Residential Lawn Soils

NASA Astrophysics Data System (ADS)

Smith, M. L.; Band, L. E.

2009-12-01

Land development practices result in compacted soils that filter less water, increase surface runoff and decrease groundwater infiltration. Literature review of soil infiltration rates reveals that developed sites’ rates, 0.1 to 24 cm/hr, are reduced when compared to rates of undeveloped sites, 14.7 to 48.7 cm/hr. Yet, most hydrologic models neglect the impacts of residential soil compaction on infiltration and runoff. The objectives of this study included: determination of differences between soil properties of forested and residential lawn sites in Baltimore Ecosystem Study; parcel-scale location impacts on soil properties; and the impact of social and physical factors on the distribution of soil properties of residential lawns. Infiltration measures were collected in situ using a Cornell Sprinkle Infiltrometer and soil cores were collected for water retention and texture analysis. These soil properties were paired with GIS data relating to age of house construction, property value, parcel area, percent canopy cover per parcel and parcel distance from stream. The study finds that saturated infiltration rates in residential lawn soils are significantly lower than forest soils due to reduced macroporosity of residential lawn soils. Intra-parcel differences in bulk density and soil depth indicate that runoff from residential lawns is more likely from near-house and near-curb locations than the mid-front or backyards. The range of infiltration rate, bulk density and percent organic matter can be explained by readily attainable social and physical factors—age of house construction and parcel distance to stream. The impacts of land management on soil properties appear to be more prominent than percent canopy.

Evaluation of a KeyStone/Tensar geogrid retaining wall system : final report.

DOT National Transportation Integrated Search

1992-01-01

The KeyStone/Tensar Geogrid retaining wall system is an alternative to conventional reinforced concrete retaining wall structures. KeyStone concrete wall units, Tensar geogrid, and compacted soils are combined to form a reinforced soil mass that toge...

Compacted dimensions and singular plasmonic surfaces.

PubMed

Pendry, J B; Huidobro, Paloma Arroyo; Luo, Yu; Galiffi, Emanuele

2017-11-17

In advanced field theories, there can be more than four dimensions to space, the excess dimensions described as compacted and unobservable on everyday length scales. We report a simple model, unconnected to field theory, for a compacted dimension realized in a metallic metasurface periodically structured in the form of a grating comprising a series of singularities. An extra dimension of the grating is hidden, and the surface plasmon excitations, though localized at the surface, are characterized by three wave vectors rather than the two of typical two-dimensional metal grating. We propose an experimental realization in a doped graphene layer. Copyright © 2017, American Association for the Advancement of Science.

Exploiting Soil Moisture, Precipitation, and Streamflow Observations to Evaluate Soil Moisture/Runoff Coupling in Land Surface Models

NASA Astrophysics Data System (ADS)

Crow, W. T.; Chen, F.; Reichle, R. H.; Xia, Y.; Liu, Q.

2018-05-01

Accurate partitioning of precipitation into infiltration and runoff is a fundamental objective of land surface models tasked with characterizing the surface water and energy balance. Temporal variability in this partitioning is due, in part, to changes in prestorm soil moisture, which determine soil infiltration capacity and unsaturated storage. Utilizing the National Aeronautics and Space Administration Soil Moisture Active Passive Level-4 soil moisture product in combination with streamflow and precipitation observations, we demonstrate that land surface models (LSMs) generally underestimate the strength of the positive rank correlation between prestorm soil moisture and event runoff coefficients (i.e., the fraction of rainfall accumulation volume converted into stormflow runoff during a storm event). Underestimation is largest for LSMs employing an infiltration-excess approach for stormflow runoff generation. More accurate coupling strength is found in LSMs that explicitly represent subsurface stormflow or saturation-excess runoff generation processes.

Effect of site treatments on soil temperature and moisture and oak and pine growth and nutrient concentrations

Treesearch

Felix, Jr. Ponder

2003-01-01

Five years after planting, measurements of soil moisture and temperature, leaf nutrient concentrations and growth, were compared for plots of northern red oak, white oak, and shortleaf pine for treatment combinations that included two levels each of harvesting intensity (organic matter removal), site disturbance (soil compaction), and weed control (control of the...

Detrimental soil disturbance associated with timber harvest systems on National Forests in the Northern Region

Treesearch

Derrick Reeves; Deborah Page-Dumroese; Mark Coleman

2011-01-01

Maintaining site productivity on forested lands within the National Forest System is a Federal mandate. To meet this mandate, soil conditions on timber harvest units within the Northern Region of the USDA Forest Service cannot exceed a threshold of 15% areal extent of detrimental soil disturbance (DSD; defined as a combination of compaction, puddling, rutting, burning...

How much land for your sand: effects of vegetation and compaction on crevasse splay formation

NASA Astrophysics Data System (ADS)

Nienhuis, J.; Tornqvist, T. E.; Esposito, C. R.

2016-12-01

Crevasse splays, failed avulsions that make up a significant portion of fluvio-deltaic overbank architecture in the Mississippi River Delta, are a natural analog for sediment diversions that are being planned to rebuild or sustain coastal wetlands. Here we use Delft3D to study the rates and mechanisms of crevasse splay growth. Because crevasse splays often form in peat-rich and vegetated environments, we have modified Delft3D to include simple formulations for the dynamic interaction between morphodynamics, vegetation, and soil compaction. Detailed stratigraphic data from prehistoric splays in the Mississippi River Delta provide useful constraints on long-term compaction rates, sedimentology, and splay volumes. We find that compaction and the absence of vegetation increase the lifespan of crevasse splays, sometimes from 900 to 4000 flood days (days during which the crevasse is geomorphically active, equivalent to model days in our simulations). Additionally, we find that in a few tested scenarios vegetation primarily acts to increase channel depths and flush out fine-grained sediment towards the flood-basin, decreasing the bulk mud capture efficiency of the splay. One model experiment with moderate vegetation heights and low susceptibility for soil compaction was a particularly "efficient" sediment diversion: every 1 m3 of imported sediment resulted in 2.55 m2 of new land.

Estimation of potential runoff-contributing areas in the Kansas-Lower Republican River Basin, Kansas

USGS Publications Warehouse

Juracek, Kyle E.

1999-01-01

Digital soils and topographic data were used to estimate and compare potential runoff-contributing areas for 19 selected subbasins representing soil, slope, and runoff variability within the Kansas-Lower Republican (KLR) River Basin. Potential runoff-contributing areas were estimated separately and collectively for the processes of infiltration-excess and saturation-excess overland flow using a set of environmental conditions that represented high, moderate, and low potential runoff. For infiltration-excess overland flow, various rainfall intensities and soil permeabilities were used. For saturation-excess overland flow, antecedent soil-moisture conditions and a topographic wetness index were used. Results indicated that the subbasins with relatively high potential runoff are located in the central part of the KLR River Basin. These subbasins are Black Vermillion River, Clarks Creek, Delaware River upstream from Muscotah, Grasshopper Creek, Mill Creek (Wabaunsee County), Soldier Creek, Vermillion Creek (Pottawatomie County), and Wildcat Creek. The subbasins with relatively low potential runoff are located in the western one-third of the KLR River Basin, with one exception, and are Buffalo Creek, Little Blue River upstream from Barnes, Mill Creek (Washington County), Republican River between Concordia and Clay Center, Republican River upstream from Concordia, Wakarusa River downstream from Clinton Lake (exception), and White Rock Creek. The ability to distinguish the subbasins as having relatively high or low potential runoff was possible mostly due to the variability of soil permeability across the KLR River Basin.

Statistical and Multifractal Evaluation of Soil Compaction in a Vineyard

NASA Astrophysics Data System (ADS)

Marinho, M.; Raposo, J. R.; Mirás Avalos, J. M.; Paz González, A.

2012-04-01

One of the detrimental effects caused by agricultural machines is soil compaction, which can be defined by an increase in soil bulk density. Soil compaction often has a negative impact on plant growth, since it reduces the macroporosity and soil permeability and increases resistance to penetration. Our research explored the effect of the agricultural machinery on soil when trafficking through a vineyard at a small spatial scale, based on the evaluation of the soil compaction status. The objectives of this study were: i) to quantify soil bulk density along transects following wine row, wheel track and outside track, and, ii) to characterize the variability of the bulk density along these transects using multifractal analysis. The field work was conducted at the experimental farm of EVEGA (Viticulture and Enology Centre of Galicia) located in Ponte San Clodio, Leiro, Orense, Spain. Three parallel transects were marked on positions with contrasting machine traffic effects, i.e. vine row, wheel-track and outside-track. Undisturbed samples were collected in 16 points of each transect, spaced 0.50 m apart, for bulk density determination using the cylinder method. Samples were taken in autumn 2011, after grape harvest. Since soil between vine rows was tilled and homogenized beginning spring 2011, cumulative effects of traffic during the vine growth period could be evaluated. The distribution patterns of soil bulk density were characterized by multifractal analysis carried out by the method of moments. Multifractality was assessed by several indexes derived from the mass exponent, τq, the generalized dimension, Dq, and the singularity spectrum, f(α), curves. Mean soil bulk density values determined for vine row, outside-track and wheel-track transects were 1.212 kg dm-3, 1.259 kg dm-3and 1.582 kg dm-3, respectively. The respective coefficients of variation (CV) for these three transects were 7.76%, 4.82% and 2.03%. Therefore mean bulk density under wheel-track was 30.5% higher than along the vine row. Vine row and outside-track positions showed not significant differences between means. The bulk density of the wheel-track transect also showed the lowest CV. The multifractal spectra of the three transects were asymmetric curves, rather short toward the left and much longer toward the right. The width of the right deviating shaped multifractal spectra was ranked as: wine row > outside-track ≈ wheel-track. Entropy dimension, D1, was 0.998, 0.992 and 0.992 for vine row, outside-track and track transects, respectively. These results show different patterns of variability of bulk density for parallel transects. They also suggest that multifractal parameters may be useful in assessing the variability of other soil properties such as soil particle density, soil porosity or soil water content, at different spatial scales as well. Acknowledgments. This work was funded in part by Spanish Ministry of Science and Innovation (MICINN) in the frame of project CGL2009-13700-C02. Financial support from CAPES/GOV., Brazil, is also acknowledged by Prof. M. Marinho.

Evaluation of geofabric in undercut on MSE wall stability : executive summary report.

DOT National Transportation Integrated Search

2011-05-01

Compaction of granular base materials at sites with fine grained native soils often causes unwanted material loss due to penetration. In 2007, ODOT began placing geofabrics in the undercut of MSE walls at the soil/ granular material interface to faci...

Strength Analysis of Coconut Fiber Stabilized Earth for Farm Structures

NASA Astrophysics Data System (ADS)

Enokela, O. S.; P. O, Alada

2012-07-01

Investigation of the strength characteristic of soil from alluvial deposit of River Benue in makurdi stabilized with coconut fiber as a stabilizer was carried as local building material for farm structure. Processed coconut fibers were mixed with the soil at four different mix ratios of 1% fiber, 2% fiber, 3% fiber and 4% fiber by percentage weight with 0% fiber as control. Compaction test and compressive strength were carried out on the various stabilizing ratio. From the compaction test, the correlation between the maximum dry density and optimum moisture content is a second order polynomial with a coefficient of 63% obtained at1.91kg/m3and 20.0% respectively while the compressive strength test shows an optimum failure load of 8.62N/mm2 at 2%fibre:100% soil mix ratio at 2.16 maximum dry density.

Soil carbon storage estimation in a forested watershed using quantitative soil-landscape modeling

Treesearch

James A. Thompson; Randall K. Kolka

2005-01-01

Carbon storage in soils is important to forest ecosystems. Moreover, forest soils may serve as important C sinks for ameliorating excess atmospheric CO2. Spatial estimates of soil organic C (SOC) storage have traditionally relied upon soil survey maps and laboratory characterization data. This approach does not account for inherent variability...

[Effects of land use changes on soil water conservation in Hainan Island, China].

PubMed

Wen, Zhi; Zhao, He; Liu, Lei; OuYang, Zhi Yun; Zheng, Hua; Mi, Hong Xu; Li, Yan Min

2017-12-01

In tropical areas, a large number of natural forests have been transformed into other plantations, which affected the water conservation function of terrestrial ecosystems. In order to clari-fy the effects of land use changes on soil water conservation function, we selected four typical land use types in the central mountainous region of Hainan Island, i.e., natural forests with stand age greater than 100 years (VF), secondary forests with stand age of 10 years (SF), areca plantations with stand age of 12 years (AF) and rubber plantations with stand age of 35 years (RF). The effects of land use change on soil water holding capacity and water conservation (presented by soil water index, SWI) were assessed. The results showed that, compared with VF, the soil water holding capacity index of other land types decreased in the top soil layer (0-10 cm). AF had the lowest soil water holding capacity in all soil layers. Soil water content and maximum water holding capacity were significantly related to canopy density, soil organic matter and soil bulk density, which indicated that canopy density, soil organic matter and compactness were important factors influencing soil water holding capacity. Compared to VF, soil water conservation of SF, AF and RF were reduced by 27.7%, 54.3% and 11.5%, respectively. The change of soil water conservation was inconsistent in different soil layers. Vegetation canopy density, soil organic matter and soil bulk density explained 83.3% of the variance of soil water conservation. It was suggested that land use conversion had significantly altered soil water holding capacity and water conservation function. RF could keep the soil water better than AF in the research area. Increasing soil organic matter and reducing soil compaction would be helpful to improve soil water holding capacity and water conservation function in land management.

Effects of organic matter removal, soil compaction, and vegetation control on Collembolan populations

Treesearch

Robert J. Eaton; Mary Barbercheck; William D. Smith

2004-01-01

Collembola can be among the most numerous meso-invertebrates in the forest floor and, through their interaction with primary decomposers in the decomposition food web, may affect litter decomposition and consequently site productivity. This study was conducted to determine whether Collembolan abundance could be impacted by organic matter removal, compaction, and...

Hydraulic conductivity of compacted zeolites.

PubMed

Oren, A Hakan; Ozdamar, Tuğçe

2013-06-01

Hydraulic conductivities of compacted zeolites were investigated as a function of compaction water content and zeolite particle size. Initially, the compaction characteristics of zeolites were determined. The compaction test results showed that maximum dry unit weight (γ(dmax)) of fine zeolite was greater than that of granular zeolites. The γ(dmax) of compacted zeolites was between 1.01 and 1.17 Mg m(-3) and optimum water content (w(opt)) was between 38% and 53%. Regardless of zeolite particle size, compacted zeolites had low γ(dmax) and high w(opt) when compared with compacted natural soils. Then, hydraulic conductivity tests were run on compacted zeolites. The hydraulic conductivity values were within the range of 2.0 × 10(-3) cm s(-1) to 1.1 × 10(-7) cm s(-1). Hydraulic conductivity of all compacted zeolites decreased almost 50 times as the water content increased. It is noteworthy that hydraulic conductivity of compacted zeolite was strongly dependent on the zeolite particle size. The hydraulic conductivity decreased almost three orders of magnitude up to 39% fine content; then, it remained almost unchanged beyond 39%. Only one report was found in the literature on the hydraulic conductivity of compacted zeolite, which is in agreement with the findings of this study.

Soil Aeration deficiencies in urban sites

NASA Astrophysics Data System (ADS)

Weltecke, Katharina; Gaertig, Thorsten

2010-05-01

Soil aeration deficiencies in urban sites Katharina Weltecke and Thorsten Gaertig On urban tree sites reduction of soil aeration by compaction or sealing is an important but frequently underestimated factor for tree growth. Up to 50% of the CO2 assimilated during the vegetation period is respired in the root space (Qi et al. 1994). An adequate supply of the soil with oxygen and a proper disposal of the exhaled carbon dioxide are essential for an undisturbed root respiration. If the soil surface is smeared, compacted or sealed, soil aeration is interrupted. Several references show that root activity and fine root growth are controlled by the carbon dioxide concentration in soil air (Qi et al.1994, Burton et al. 1997). Gaertig (2001) found that decreasing topsoil gas permeability leads to reduced fine root density and hence to injury in crown structure of oaks. In forest soils a critical CO2 concentration of more than 0.6 % indicates a bad aeration status (Gaertig 2001). The majority of urban tree sites are compacted or sealed. The reduction of soil aeration may lead to dysfunctions in the root space and consequently to stress during periods of drought, which has its visible affects in crown structure. It is reasonable to assume that disturbances in soil aeration lead to reduced tree vigour and roadworthiness, resulting in high maintenance costs. The assessment of soil aeration in urban sites is difficult. In natural ecosystems the measurement of gas diffusivity and the gas-chromatical analysis of CO2 in soil air are accepted procedures in analyzing the state of aeration (Schack-Kirchner et al. 2001, Gaertig 2001). It has been found that these methods can also be applied for analyzing urban sites. In particular CO2 concentration in the soil atmosphere can be considered as a rapidly assessable, relevant and integrating indicator of the aeration situation of urban soils. This study tested the working hypothesis that soil aeration deficiencies lead to a decrease of fine root density and tree vigour on urban soils. For that purpose gas diffusivity, soil CO2 concentrations and fine root density were measured on typical urban sites in the German cities of Göttingen, Mannheim, and Kassel. The known characteristics of soil aeration on forest sites could be affirmed for urban soils. A negative correlation was found between gas diffusion coefficients and CO2 concentration as well as between fine root extension and CO2 concentration. Changes in crown structure of beech indicating a loss of vigour were found at sites with disturbed aeration. Diffusivity patterns and CO2 concentrations of different specific urban soil sealing types were found. On more natural sites (mulch, grass) increased gas diffusion and low CO2 concentration were present. In contrast, on more compacted or sealed areas (asphalt, paving stone, macadamised road surface) the exchange between soil air and atmosphere was nearly disconnected and soil CO2 concentrations partly exceeded the known critical value of 0.6 % up to tenfold. Literature Burton, A. J.; Pregitzer, K. S.; Zogg, G. P. und Zak D. R. (1997): Effect of measurement CO2 concentrations on sugar maple root respiration. In: Canadian journal of Forest Research, H. 17, S. 421-427. Gaertig, T. (2001): Bodengashaushalt, Feinwurzeln und Vitalität von Eichen. In: Freiburger Bodenkundliche Abhandlungen, H. 40, S. 157. Qi, J.; Marshall, J. D.; Mattson, K. G. (1994): High soil carbon dioxide concentrations inhibit root respiration of Douglas fir. In: New Phytol., Jg. 128, H. 3, S. 435-442. Schack-Kirchner, H.; Gaertig, T.; Wilpert, K. v.; Hildebrand, E. E. (2001): A modified McIntyre and Phillip approach to measure top-soil gas diffusivity in-situ. In: J. Plant Nutr. Soil Sci., Jg. 164, S. 253-258.

Lake States Aspen Productivity Following Soil Compaction and Organic Matter Removal

Treesearch

Douglas M. Stone

2002-01-01

Aspen (Populus tremuloides Michx. and P. grandidentata Michx.) provides wood products, watershed protection, and wildlife habitat for numerous game and non-game species across the northern Great Lakes region. Sustaining the productivity of these ecosystems requires maintaining soil productivity. Management activities that decrease...

Minimizing soil impacts from forest operations

Treesearch

Emily A. Carter

2011-01-01

Several studies were conducted by Forest Service researchers and University and Industrial collaborators that investigated the potential for lessening soil surface disturbances and compaction in forest operations through modifications of machine components or harvest systems. Specific machine modifications included change in tire size, use of dual tire systems,...

X-ray microtomography analysis of soil structure deformation caused by centrifugation

NASA Astrophysics Data System (ADS)

Schlüter, Steffen; Leuther, Frederic; Vogler, Steffen; Vogel, Hans-Jörg

2016-04-01

Centrifugation provides a fast method to measure soil water retention curves over a wide moisture range. However, deformation of soil structure may occur at high angular velocities in the centrifuge. The objective of this study was to capture these changes in soil structure with X-ray microtomography and to measure local deformations via digital volume correlation. Two samples were investigated that differ in texture and rock content. A detailed analysis of the pore space reveals an interplay between shrinkage due to drying and soil compaction due to compression. Macroporosity increases at moderate angular velocity because of crack formation due to moisture release. At higher angular velocities, corresponding to capillary pressure of <-100kPa, macroporosity decreases again because of structure deformation due to compression. While volume changes due to swelling clay minerals are immanent to any drying process, the compaction of soil is a specific drawback of the centrifugation method. A new protocol for digital volume correlation was developed to analyze the spatial heterogeneity of deformation. In both samples the displacement of soil constituents is highest in the top part of the sample and exhibits high lateral variability explained by the spatial distribution of macropores in the sample. Centrifugation should therefore only be applied after the completion of all other hydraulic or thermal experiments, or any other analysis that depends on the integrity of soil structure.

X-ray microtomography analysis of soil structure deformation caused by centrifugation

NASA Astrophysics Data System (ADS)

Schlüter, S.; Leuther, F.; Vogler, S.; Vogel, H.-J.

2016-01-01

Centrifugation provides a fast method to measure soil water retention curves over a wide moisture range. However, deformation of soil structure may occur at high angular velocities in the centrifuge. The objective of this study was to capture these changes in soil structure with X-ray microtomography and to measure local deformations via digital volume correlation. Two samples were investigated that differ in texture and rock content. A detailed analysis of the pore space reveals an interplay between shrinkage due to drying and soil compaction due to compression. Macroporosity increases at moderate angular velocity because of crack formation due to moisture release. At higher angular velocities, corresponding to capillary pressure of ψ < -100 kPa, macroporosity decreases again because of structure deformation due to compression. While volume changes due to swelling clay minerals are immanent in any drying process, the compaction of soil is a specific drawback of the centrifugation method. A new protocol for digital volume correlation was developed to analyze the spatial heterogeneity of deformation. In both samples the displacement of soil constituents is highest in the top part of the sample and exhibits high lateral variability explained by the spatial distribution of macropores in the sample. Centrifugation should therefore only be applied after the completion of all other hydraulic or thermal experiments, or any other analysis that depends on the integrity of soil structure.

Estimation of Anthropogenic Uranium Concentration in Japanese Agricultural Soils from Phosphatic Fertilizers

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

Tagami, K.; Uchida, S.; Takeda, H.

2006-07-01

In this study, estimation of excess amount of uranium in Japanese agricultural soils due to phosphatic fertilizer application were carried out, by measuring concentrations of total U and Th in 82 soils collected throughout Japan by inductively coupled plasma mass spectrometry (ICP-MS). Since Japanese non-agricultural fields have an average U/Th ratio of 0.23, thus, using U/Th ratios in non-agricultural areas, we thought that it is possible to calculate amounts of excess U due to the application of fertilizers. It was estimated that about 50% of total U in paddy field soils (range: 4-78%) and about 48% of total U inmore » upland field soils (range: 4-74%) were originated from the phosphatic fertilizers. (authors)« less

Effects of slash, machine passes, and soil moisture on penetration resistance in a cut-to-length harvesting

Treesearch

Han-Sup Han; Debbie Page-Dumroese; Sang-Kyun Han; Joanne Tirocke

2006-01-01

Multiple entries into forest stands are often needed for fire hazard reduction and ecosystem restoration treatments in the Inland-Northwest U.S.A. region. However, soil compaction occurring from mechanized harvesting operations often remains for many years and may contribute to a decline in long-term site productivity. A controlled experiment on a silt loam soil was...

Effects of land use and land cover on selected soil quality indicators in the headwater area of the Blue Nile basin of Ethiopia.

PubMed

Teferi, Ermias; Bewket, Woldeamlak; Simane, Belay

2016-02-01

Understanding changes in soil quality resulting from land use and land management changes is important to design sustainable land management plans or interventions. This study evaluated the influence of land use and land cover (LULC) on key soil quality indicators (SQIs) within a small watershed (Jedeb) in the Blue Nile Basin of Ethiopia. Factor analysis based on principal component analysis (PCA) was used to determine different SQIs. Surface (0-15 cm) soil samples with four replications were collected from five main LULC types in the watershed (i.e., natural woody vegetation, plantation forest, grassland, cultivated land, and barren land) and at two elevation classes (upland and midland), and 13 soil properties were measured for each replicate. A factorial (2 × 5) multivariate analysis of variance (MANOVA) showed that LULC and altitude together significantly affected organic matter (OM) levels. However, LULC alone significantly affected bulk density and altitude alone significantly affected bulk density, soil acidity, and silt content. Afforestation of barren land with eucalypt trees can significantly increase the soil OM in the midland part but not in the upland part. Soils under grassland had a significantly higher bulk density than did soils under natural woody vegetation indicating that de-vegetation and conversion to grassland could lead to soil compaction. Thus, the historical LULC change in the Jedeb watershed has resulted in the loss of soil OM and increased soil compaction. The study shows that a land use and management system can be monitored if it degrades or maintains or improves the soil using key soil quality indicators.

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

Phosphorus dynamics in long-term flooded, drained and reflooded soils

USDA-ARS?s Scientific Manuscript database

In flooded areas, soils are often exposed to standing water and subsequent drainage, thus over fertilization can release excess phosphorus (P) into surface water and groundwater. To investigate P release and transformation processes in flooded alkaline soils, we flooded-drained-reflooded two soils f...

Comparative research on tillable properties of diatomite-improved soils in the Yangtze River Delta region, China.

PubMed

Qu, Ji-Li; Zhao, Dong-Xue

2016-10-15

To improve soil texture and structure, techniques associated with physical, biological or chemical aspects are generally adopted, among which diatomite is an important soil conditioner. However, few studies have been conducted to investigate the physical, hydraulic and tillage performance of diatomite-improved soils. Consistency limits and compaction properties were investigated in this study, and several performance indicators were compared, such as the liquid limit, plastic limit and compactability, of silt, silt loam and silty-clay loam soils to which diatomite was added at volumetric ratios of 0%, 10%, 20%, and 30%. The results showed that diatomite significantly (p<0.05) improved the consistency limits, with the most preferred effects in the silt soil. The liquid limits were increased by 53.9%, 27.3%, and 14.7%, in the silt, silt loam and silty-clay loam soils, respectively, when the volumetric ratio was 30%. While diatomite lowered the maximum dry bulk density (MBD) of the classified soils, the optimum moisture content (OMC) was increased overall. The trend was consistent with the proportion of diatomite, and MBD decreased by 8.7%, 10.3%, and 13.2% in the silt, silt loam and silty-clay loam soils when 30% diatomite was mixed, whereas OMC increased by 28.7%, 22.4%, and 25.3%, respectively. Additionally, aggregate stability was negatively correlated with MBD but positively correlated with OMC. Diatomite exerts positive effects on soil mechanical strength, suggesting that soils from sludge farms are more tillable with a larger stabilized and workable matrix. Copyright © 2016 Elsevier B.V. All rights reserved.

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.

Application of Magnetic and Geotechnical Methods for Archaeological Site Investigations

DTIC Science & Technology

2011-07-01

national historic preservation act NRM natural remnant magnetism NS north-south nT nano Tesla ID inside diameter OSB oriented strand board psi...3.4 Soil Box Experiments Compaction tests were conducted by loading soil into a wooden box (1 m3) constructed of oriented strand board ( OSB ) and

Agricultural Education Science Activity--Nos. PS 1-6.

ERIC Educational Resources Information Center

Ohio State Univ., Columbus. Agricultural Curriculum Materials Service.

This packet contains six science learning activities that can be used in agricultural education courses. The activities cover these topics: (1) determining the effects of soil drainage on plant growth and development; (2) determining the effect of soil compaction on plant growth and development; (3) inoculating legume seeds to promote nodule…

Improved or unimproved urban areas effect on soil and water quality

USDA-ARS?s Scientific Manuscript database

Construction in urban areas usually results in compacted soil, which restricts plant growth and infiltration. Nutrients may be lost in storm runoff water and sediment. The purpose of this study was to determine if existing lawns benefit from aeration and surface compost additions without negative im...

EVALUATION OF THE EFFECTIVENESS OF RIPARIAN ZONE RESTORATION IN THE SOUTHERN APPALACHIANS BY ASSESSING SOIL MICROBIAL POPULATIONS

EPA Science Inventory

Microbial biomass, nitrifiers and denitrifiers in surface soil (0?10 cm) were quantified in a riparian zone restoration project at Coweeta, North Carolina, USA. Four treatments are included in this study: (1) a degraded (+N) riparian zone with continued compaction, vegetation rem...

Soil disturbance-tree growth relations in central Idaho clearcuts

Treesearch

James L. Clayton; Gary Kellogg; Neal Forrester

1987-01-01

Two central Idaho clearcuts regenerated naturally to lodgepole pine (Pinus contorta) and one regenerated with planted ponderosa pine (Pinus ponderosa) were evaluated to see if soil compaction and displacement affected growth as measured by tree height, diameter at breast height, and radial growth increment. Pole-sized trees ranging...

Use of coal fly ash and other waste products in soil stabilization and road construction including non-destructive testing of roadways.

DOT National Transportation Integrated Search

2012-06-01

An extensive laboratory testing program was performed on subgrade soils stabilized using fly ash and : lime kiln dust. The laboratory program included measurements of: compaction curves, small strain elastic moduli, : resilient modulus (Mr), Briaud C...

Use of coal fly ash and other waste products in soil stabilization and road construction-including non-destructive testing of roadways.

DOT National Transportation Integrated Search

2012-02-01

An extensive laboratory testing program was performed on subgrade soils stabilized using fly ash and lime kiln dust. The laboratory : program included measurements of: compaction curves, small strain elastic moduli, resilient modulus (Mr), Briaud Com...

24 CFR 3285.312 - Footings.

Code of Federal Regulations, 2014 CFR

2014-04-01

... section. Footings must be placed on undisturbed soil or fill compacted to 90 percent of maximum relative... (psi). Site-specific soil conditions or design load requirements may also require the use of... footings must consist of a minimum of two layers of nominal 2-inch thick pressure-treated wood, a single...

24 CFR 3285.312 - Footings.

Code of Federal Regulations, 2012 CFR

2012-04-01

... section. Footings must be placed on undisturbed soil or fill compacted to 90 percent of maximum relative... (psi). Site-specific soil conditions or design load requirements may also require the use of... footings must consist of a minimum of two layers of nominal 2-inch thick pressure-treated wood, a single...

24 CFR 3285.312 - Footings.

Code of Federal Regulations, 2011 CFR

2011-04-01

... section. Footings must be placed on undisturbed soil or fill compacted to 90 percent of maximum relative... (psi). Site-specific soil conditions or design load requirements may also require the use of... footings must consist of a minimum of two layers of nominal 2-inch thick pressure-treated wood, a single...

24 CFR 3285.312 - Footings.

Code of Federal Regulations, 2010 CFR

2010-04-01

... section. Footings must be placed on undisturbed soil or fill compacted to 90 percent of maximum relative... (psi). Site-specific soil conditions or design load requirements may also require the use of... footings must consist of a minimum of two layers of nominal 2-inch thick pressure-treated wood, a single...

24 CFR 3285.312 - Footings.

Code of Federal Regulations, 2013 CFR

2013-04-01

... section. Footings must be placed on undisturbed soil or fill compacted to 90 percent of maximum relative... (psi). Site-specific soil conditions or design load requirements may also require the use of... footings must consist of a minimum of two layers of nominal 2-inch thick pressure-treated wood, a single...

Towards a new proxy of continental atmospheric humidity: the triple oxygen isotopic composition of plant biosilica

NASA Astrophysics Data System (ADS)

Alexandre, A. E.; Pauchet, S.; Landais, A.; Piel, C.; Devidal, S.; Roy, J.; Vallet-Coulomb, C.; Sonzogni, C.; Pasturel, M.; Cornuault, P.; Xin, J.; Mazur, J. C.; Prie, F.; Bentaleb, I.

2016-12-01

There is a serious lack of proxy suitable for reconstructing, in a quantitative way, past changes of continental atmospheric humidity. This reduces the possibility to make model-data comparisons necessary for the implementation of climate models. Over the past 10 years, analytical developments have enabled a few laboratories to reach sufficient precision for measuring the triple oxygen isotopes, expressed by the 17O-excess, in water, water vapor, atmospheric oxygen, and minerals. The 17O-excess represents an alternative to d-excess for investigating relative humidity conditions that prevail during water evaporation. The 17O-excess of water results from the increase of kinetic isotopic fractionation at evaporative sites as a function of decreasing relative humidity. This mechanism occurs at large scales, i.e. during seawater evaporation or during plant canopies transpiration. Unlike deuterium-excess, 17O-excess is supposed to be insensitive to temperature and less sensitive than δD and δ18O to equilibrium fractionation during transport and precipitation. Additionally, the 17O-excess is recorded in biogenic minerals less prone to weathering than organic compounds. Here, we calibrate the 17O-excess of plant biosilica as a new air humidity proxy. First, we examined the behavior of the 17O-excess in soil water, leaf water and phytoliths in growth chambers in response to changes in relative humidity. Second, we measured the 17O-excess of soil phytolith assemblages from inter-tropical savannas and forests distributed along humidity transects. Both approaches show similar dependency of phytolith 17O-excess to relative humidity. The results allow to discuss future calibration directions aimed at estimating the precision of the obtained relationship and at quantifying the successive isotopic fractionations in play at the soil-plant-atmosphere interface, to provide a strong proxy of past atmospheric relative humidity.

Cancer risk from incidental ingestion exposures to PAHs associated with coal-tar-sealed pavement

USGS Publications Warehouse

Williams, E. Spencer; Mahler, Barbara J.; Van Metre, Peter C.

2012-01-01

Recent (2009-10) studies documented significantly higher concentrations of polycyclic aromatic hydrocarbons (PAHs) in settled house dust in living spaces and soil adjacent to parking lots sealed with coal-tar-based products. To date, no studies have examined the potential human health effects of PAHs from these products in dust and soil. Here we present the results of an analysis of potential cancer risk associated with incidental ingestion exposures to PAHs in settings near coal-tar-sealed pavement. Exposures to benzo[a]pyrene equivalents were characterized across five scenarios. The central tendency estimate of excess cancer risk resulting from lifetime exposures to soil and dust from nondietary ingestion in these settings exceeded 1 × 10–4, as determined using deterministic and probabilistic methods. Soil was the primary driver of risk, but according to probabilistic calculations, reasonable maximum exposure to affected house dust in the first 6 years of life was sufficient to generate an estimated excess lifetime cancer risk of 6 × 10–5. Our results indicate that the presence of coal-tar-based pavement sealants is associated with significant increases in estimated excess lifetime cancer risk for nearby residents. Much of this calculated excess risk arises from exposures to PAHs in early childhood (i.e., 0–6 years of age).

Electrical Imaging of Infiltration in Agricultural Soils on Long Island, New York

NASA Astrophysics Data System (ADS)

Lampousis, A.; Kenyon, P. M.; Sanwald, K.; Steiner, N.

2007-12-01

High resolution electrical resistivity imaging of vadose zone infiltration experiments was conducted on agricultural soils by the City College and Graduate Center of CUNY, in cooperation with Cornell University's Agricultural Stewardship Program and Long Island Horticultural Research and Extension Center (LIHREC) in Riverhead, New York. Measurements were made in active vineyards with a commercial resistivity imaging system, using a half- meter electrode spacing. Soils considered were Riverhead sandy loam (RdA), Haven loam (HaA), and Bridgehampton silty loam (BgA). The Riverhead and Haven soils are the most common types found on eastern Long Island. The Bridgehampton is considered the most fertile. Soil samples and measurements of soil compaction were collected at the same time as the geophysical measurements. In addition, remote sensing data were obtained for the three sites and processed to produce normalized difference vegetation index (NDVI) data to evaluate potential correlations between vegetation vigor, soil texture and water migration patterns. Applications of this study include continuous water content monitoring in high value cash crops (precision agriculture). Changes in electrical resistivity during infiltration are clearly visible at all three locations. Preliminary analysis of the results shows correlations of baseline resistivity with particle size distributions and correlations between changes in resistivity during infiltration and soil compaction data. Time-lapse electrical images of the three sites will also be compared with published properties for these soils, including particle size distribution, saturated hydraulic conductivity, available water capacity, and surface texture.

CO2 migration in the vadose zone: experimental and numerical modelling of controlled gas injection

NASA Astrophysics Data System (ADS)

gasparini, andrea; credoz, anthony; grandia, fidel; garcia, david angel; bruno, jordi

2014-05-01

The mobility of CO2 in the vadose zone and its subsequent transfer to the atmosphere is a matter of concern in the risk assessment of the geological storage of CO2. In this study the experimental and modelling results of controlled CO2 injection are reported to better understanding of the physical processes affecting CO2 and transport in the vadose zone. CO2 was injected through 16 micro-injectors during 49 days of experiments in a 35 m3 experimental unit filled with sandy material, in the PISCO2 facilities at the ES.CO2 centre in Ponferrada (North Spain). Surface CO2 flux were monitored and mapped periodically to assess the evolution of CO2 migration through the soil and to the atmosphere. Numerical simulations were run to reproduce the experimental results, using TOUGH2 code with EOS7CA research module considering two phases (gas and liquid) and three components (H2O, CO2, air). Five numerical models were developed following step by step the injection procedure done at PISCO2. The reference case (Model A) simulates the injection into a homogeneous soil(homogeneous distribution of permeability and porosity in the near-surface area, 0.8 to 0.3 m deep from the atmosphere). In another model (Model B), four additional soil layers with four specific permeabilities and porosities were included to predict the effect of differential compaction on soil. To account for the effect of higher soil temperature, an isothermal simulation called Model C was also performed. Finally, the assessment of the rainfall effects (soil water saturation) on CO2 emission on surface was performed in models called Model D and E. The combined experimental and modelling approach shows that CO2 leakage in the vadose zone quickly comes out through preferential migration pathways and spots with the ranges of fluxes in the ground/surface interface from 2.5 to 600 g·m-2·day-1. This gas channelling is mainly related to soil compaction and climatic perturbation. This has significant implications to design adapted detection and monitoring strategies of early leakage in commercial CO2 storage. The presence of soils with different compactions at surface influences the CO2 dispersion. The inclusion of soils with different permeability, porosity and liquid saturation results in preferential pathways. The formation of preferential pathways in the soil and hot spots on the surface has commonly been observed in natural systems where deep CO2 fluxes interact with shallow aquifers. Increase of ambient temperature increases CO2 fluxes intensity whereas rainfall decreases CO2 emission in gas phase and trap it as aqueous species in the porous media of the soil. A good accuracy has been obtained for surface CO2 fluxes location and intensity between experimental and modelling results taking into account the selected equation of state, the soil characteristics and the operational conditions. Phenomena of compaction and preferential pathways located only in the first centimetres of the soil can explain the heterogeneity of CO2 fluxes in the 16 m2 surface area of PISCO2 experimental platform.

Integration of remote sensing and ground-based techniques for the study of land degradation phenomena in coastal areas.

NASA Astrophysics Data System (ADS)

Imbrenda, Vito; Coluzzi, Rosa; Calamita, Giuseppe; Luigia Giannossi, Maria; D'Emilio, Mariagrazia; Lanfredi, Maria; Makris, John; Palombo, Angelo; Pascucci, Simone; Santini, Federico; Margiotta, Salvatore; Emanuela Bonomo, Agnese; De Martino, Gregory; Perrone, Angela; Rizzo, Enzo; Pignatti, Stefano; Summa, Vito; Simoniello, Tiziana

2015-04-01

Land degradation processes, such as salinization and waterlogging, are increasingly affecting extensive areas devoted to agriculture threatening the sustainability of farming practices. Soil salinization typically appears as an excess accumulation of salt generally pronounced at the soil surface. Commonly, soil salinity is defined and measured by means of laboratory measurements of the electrical conductivity of liquid extracted from saturated soil-paste or different soil-water suspensions. Lab measurements are generally time consuming, costly, destructive, untimely for practical situations where the determination of the causes and/or the assessment of management practices are of interest. Recently, emerging survey techniques proved to be powerful tools to support soil salinity appraisal reducing costs and increasing the amount of spatial information. In the frame of PRO-LAND project (PO-FESR Basilicata 2007-2013) the research activities have been focused on the study of a complex salinization phenomenon occurring in a coastal environment of the Basilicata region (Southern Italy) as a result of natural and anthropic disturbances. The study area is located in the southernmost part of the Bradanic Trough along the sandy Ionian coastal plain. The hydrogeological conditions affect shallowness of the aquifer (45-50 cm below the ground) allowing the occurrence of seawater intrusion. Moreover, during last century, human activities, i.e. built-up of dams, the emergence of farms and industries, played a relevant role in the alteration of soil and groundwater quality of the area. In this work, both ground-based and remote sensing data were used. First, a geophysical mapping of electrical conductivity was carried out using a multi-frequency portable electro-magnetic induction (EMI) sensor. Based on the geophysical mapping and on optimization sampling approach, a number of locations were identified to collect soil samples for the geomineralogical characterization. Airborne images were acquired on the study area by the hyperspectral Compact Airborne Spectrographic Imager (CASI) - 1500 to derive indices sensitive to soil degradation. The main aim of this research activity was to improve the knowledge about the most relevant driving forces, contributing to the analyzed degradation process, and their interplay within the study area. In the light of this, we also would like to suggest the most appropriate best practices and restoration activities to be undertaken.

Comparison of Shear-wave Profiles for a Compacted Fill in a Geotechnical Test Pit

NASA Astrophysics Data System (ADS)

Sylvain, M. B.; Pando, M. A.; Whelan, M.; Bents, D.; Park, C.; Ogunro, V.

2014-12-01

This paper investigates the use of common methods for geological seismic site characterization including: i) multichannel analysis of surface waves (MASW),ii) crosshole seismic surveys, and iii) seismic cone penetrometer tests. The in-situ tests were performed in a geotechnical test pit located at the University of North Carolina at Charlotte High Bay Laboratory. The test pit has dimensions of 12 feet wide by 12 feet long by 10 feet deep. The pit was filled with a silty sand (SW-SM) soil, which was compacted in lifts using a vibratory plate compactor. The shear wave velocity values from the 3 techniques are compared in terms of magnitude versus depth as well as spatially. The comparison was carried out before and after inducing soil disturbance at controlled locations to evaluate which methods were better suited to captured the induced soil disturbance.

Biochar effects on phosphorus pools in three soils from Minnesota

USDA-ARS?s Scientific Manuscript database

This greenhouse study was set up to assess the changes in the soil phosphorus (P) pools of three soils used for agricultural production in Minnesota as a result of biochar application and crop nutrient uptake. The soils included: excessively well-drained Hubbard loamy sand; poorly drained, calcareou...

Soil-profile distribution of inorganic N during 6 years of integrated crop-livestock management

USDA-ARS?s Scientific Manuscript database

Excessive accumulation of soil nitrate-N can threaten water and air quality. How integrated crop-livestock systems might influence soil-profile nitrate-N accumulation has not been investigated. Therefore, we determined soil nitrate-N accumulation during 6 years of evaluation of diverse cropping sy...

Compact, Lightweight Dual- Frequency Microstrip Antenna Feed for Future Soil Moisture and Sea Surface Salinity Missions

NASA Technical Reports Server (NTRS)

Yueh, Simon H.; Wilson, William J.; Njoku, Eni; Hunter, Don; Dinardo, Steve; Kona, Keerti S.; Manteghi, Majid; Gies, Dennis; Rahmat-Samii, Yahya

2004-01-01

The development of a compact, lightweight, dual frequency antenna feed for future soil moisture and sea surface salinity (SSS) missions is described. The design is based on the microstrip stacked-patch array (MSPA) to be used to feed a large lightweight deployable rotating mesh antenna for spaceborne L-band (approx. 1 GHz) passive and active sensing systems. The design features will also enable applications to airborne sensors operating on small aircrafts. This paper describes the design of stacked patch elements, 16-element array configuration and power-divider beam forming network The test results from the fabrication of stacked patches and power divider were also described.

Mass loss and nutrient concentrations of buried wood as a function of organic matter removal, soil compaction, and vegetation control in a regenerating oak-pine forest

Treesearch

Felix Ponder; John M. Kabrick; Mary Beth Adams; Deborah S. Page-Dumroese; Marty F. Jurgensen

2017-01-01

Mass loss and nutrient concentrations of northern red oak (Quercus rubra) and white oak (Q. alba) wood stakes were measured 30 months after their burial in the upper 10 cm of soil in a regenerating forest after harvesting and soil disturbance. Disturbance treatments were two levels of organic matter (OM) removal (only...

Effects of organic matter removal, soil compaction and vegetation control on 10th year biomass and foliar nutrition: LTSP continent-wide comparisons

Treesearch

Felix Ponder Jr.; Robert L. Fleming; Shannon Berch; Matt D. Busse; John D. Elioff; Paul W. Hazlett; Richard D. Kabzems; J. Marty Kranabetter; David M. Morris; Deborah Page-Dumroese; Brian J. Palik; Robert F. Powers; Felipe G. Sanchez; D. Andrew Scott; Richard H. Stagg; Douglas M. Stone; David H. Young; Jianwei Zhang; Kim H. Ludovici; Daniel W. McKenney; Debbie S Mossa; Paul T. Sanborn; Richard A. Voldseth

2012-01-01

We examined 10th year above-ground planted tree and total stand biomass, and planted tree foliar N and P concentrations across gradients in soil disturbance at 45 North American Long-Term Soil Productivity (LTSP) installations. While ranging across several climate regions, these installations all share a common experimental design with similar measurement protocols....

Temperature dependence of soil water potential

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

Mohamed, A.M.O.; Yong, R.N.; Cheung, S.C.H.

1992-12-01

To understand the process of coupled heat and water transport, the relationship between temperature and soil water potential must be known. Two clays, Avonlea bentonite and Lake Agassiz clay, are being considered as the clay-based sealing materials for the Canadian nuclear fuel waste disposal vault. Avonlea bentonite is distinguished from Lake Agassiz clay by its high sealing potential in water. A series of experiments was performed in which the two clays were mixed with equal amounts of sand and were compacted to a dry density of 1.67 Mg/m[sup 3] under various moisture contents and temperatures. A psychrometer was placed withinmore » the compacted clay-sand to measure the soil water potential based on the electromotive force measured by the psychrometer. The results indicate that the soil water potential at a particular temperature is higher for both clay-sand mixtures than predicted by the change in the surface tension of water; this effect is much more prominent in the Avonlea bentonite and at low moisture contents. The paper presents empirical equations relating the soil water potential with the moisture content and temperature of the two clay-sand mixtures. 24 refs., 8 figs., 2 tabs.« less

Soil physical properties regulate lethal heating during burning of woody residues

Treesearch

Matt Busse; Carol Shestak; Ken Hubbert; Eric Knapp

2010-01-01

Temperatures well in excess of the lethal threshold for roots (60°C) have been measured in forest soils when woody fuels are burned. Whether this heat pulse is strongly moderated by soil moisture or soil texture is not fully understood, however. We measured soil heat profi les during 60 experimental burns, identifying changes in maximum soil temperature and heat...

Impact of Camping on Soil Properties at Strawberry Lake, North Dakota, USA

NASA Astrophysics Data System (ADS)

Brevik, Eric C.; Tibor, Matthew A.

2014-05-01

Recreational activity at campsites can cause compaction and metal contamination of soils. This study compared the bulk densities, penetration resistance values, organic matter contents, and Zn, Mn, and Cu contents of soils sampled from zones of varying recreational activity within the campsites at Strawberry Lake, North Dakota, USA. The results of this study showed that there were statistically significant increases in the soil bulk densities and soil penetration resistance values compared to the controls. However, the low recreational intensity has not compacted the surface soils beyond an average of 1.36 g cm-3, which is not dense enough to hinder the root growth of the surrounding vegetation. There were no statistically significant differences between the soil organic matter content of the different activity zones at the 95% confidence interval. Zinc values were four orders of magnitude and Cu values three to four orders of magnitude below US EPA guideline limits. The EPA does not have guidelines for Mn, but Mn levels were lower than reported typical natural values for a nearby area. Therefore, metal contents were not high enough to be of concern. Taken together, these results were interpreted to indicate that the low-intensity camping activities that occur at Strawberry Lake campground have not had a significant negative impact on the soils found there. Additional information on this study can be found in Tibor and Brevik (2013). Reference Tibor, M.A., and E.C. Brevik. 2013. Anthropogenic Impacts on Campsite Soils at Strawberry Lake, North Dakota. Soil Horizons 54: doi:10.2136/sh13-06-0016.

Keeping soil in the field - runoff and erosion management in asparagus crops

NASA Astrophysics Data System (ADS)

Niziolomski, Joanna; Simmons, Robert; Rickson, Jane; Hann, Mike

2016-04-01

Row crop production (including potatoes, onions, carrots, asparagus, bulbs and lettuce) is regarded as one of the most erosive agricultural cropping systems. This is a result of the many practices involved that increase erosion risk including: fine seedbed preparation, a typically short growing season where adequate ground cover protects the soil, permanent bare soil areas between crops, and often intensive harvesting methods that can damage soil structure and result in soil compaction. Sustained exposure of bare soil coupled with onsite compaction on slightly sloping land results in soil and water issues in asparagus production. Asparagus production is a growing British industry covering > 2000 ha and is worth approximately £30 million yr-1. However, no tried and tested erosion control measurements currently exist to manage associated problems. Research has recently been undertaken investigating the effectiveness of erosion control measures suitable for asparagus production systems. These consisted of surface applied wheat straw mulch and shallow soil disturbance (< 350 mm) using several tine configurations: a currently adopted winged tine, a narrow with two shallow leading tines, and a modified para-plough. These treatments were tested individually and in combination (straw mulch with each shallow soil disturbance tine configuration) using triplicated field plots situated on a working asparagus farm in Herefordshire, UK. Testing was conducted between May and November 2013. Rainfall-event based runoff and erosion measurements were taken including; runoff volume, runoff rate and total soil loss. Runoff and soil erosion was observed from all treatments. However, the surface application of straw mulch alone out performed each shallow soil disturbance practice. This suggests that runoff and erosion from asparagus production can be reduced using the simple surface application of straw.

Liquefaction under drained condition, from the lab to reality ?

NASA Astrophysics Data System (ADS)

Clément, Cécile; Aharonov, Einat; Stojanova, Menka; Toussaint, Renaud

2015-04-01

Liquefaction constitutes a significant natural hazard in relation to earthquakes and landslides. This effect can cause buildings to tilt or sink into the soil, mud-volcanoes, floatation of buried objects, long-runout landslides, etc. In this work we present a new understanding regarding the mechanism by which buildings sink and tilt during liquefaction caused by earthquakes. Conventional understanding of liquefaction explains most observed cases as occurring in an undrained, under-compacted, layer of sandy soil saturated with water [1]: According to that understanding, the under compacted sandy layer has the tendency to compact when a load is applied. In our case the load comes from ground shaking during an earthquake. When the soil compacts, the fluid pore pressure rises. Because in undrained conditions the fluid cannot flow out, the pore pressure builds up. The weight of buildings is in this case transferred from the grains of the soil to the pore water. The soil loses its rigidity and it flows like a liquid. From this model scientists made theoretical and empirical laws for geotechnical use and buildings construction. Despite the success of this conventional model in many cases, liquefied soils were also observed under drained conditions, and in previously compacted soils, which doesn't agree with the assumption of the model quoted above. One of the famous liquefaction events is the Kobe port destruction during the 1995 earthquake. A simple calculation of the Deborah number following Goren et al ([2][3]) shows that the undrained constraint was not met below the Kobe port during the 1995 earthquake. We propose another model, of liquefaction in drained granular media. According to our model the mere presence of water in granular media is enough to cause liquefaction during an earthquake, provided that the water reaches close to the surface. Our computations are based on the buoyancy force, and we take into account the static fluid pressure only. For small horizontal shaking our model predicts that the soil remains rigid. Under stronger accelerations, some of the particles, which constitute the medium, slide past each other, and the medium slowly rearranges. Yet, in this regime of shaking, the shaking is insufficient to cause the building to slide. The building sinks simply due to hydrostatic considerations, and since it is a static object in a dynamically rearranging medium. This is the case we call liquefaction. Eventually, for even stronger accelerations, both the particles and the building can slide and we predict convective movement. To test this model we run numerical simulations (granular dynamics DEM algorithm) and laboratory experiments. The numerical experiments do not include pore pressure, and only simulate buoyancy effects of water. The controlling parameters are the amplitude and frequency of the shaking, and the water level. With a saturated medium, experiments and simulations display three different behaviors: rigid, liquefaction, and convection, in agreement with our theoretical model. The peak ground acceleration (PGA) is the decisive parameter. It is important to note that for dry media and for a case when the building is fully submerged underwater, both in experiments and in simulations, the liquefaction effect disappears. Based on our work we suggest that elevated pore pressure conditions are not necessary for inducing liquefaction, and that liquefaction can occur under well drained and highly compacted soils, in situations previously considered to be safe from liquefaction. Références [1] Chi-Yuen Wang and Michael Manga. Earthquakes and Water, volume 114. Springer Verlag, 2010. [2] L. Goren, E. Aharonov, D. Sparks, and R. Toussaint. Pore pressure evolution in deforming granu- lar material : A general formulation and the infinitely stiff approximation. Journal of Geophysical Research, 115(B9), Sep 2010. [3] Liran Goren, Einat Aharonov, David Sparks, and Renaud Toussaint. The mechanical coupling of fluid-filled granular material under shear. Pure and applied geophysics, 168(12) :2289-2323, 2011.

Biogeochemistry of heavy metals in contaminated excessively moistened soils (Analytical review)

NASA Astrophysics Data System (ADS)

Vodyanitskii, Yu. N.; Plekhanova, I. O.

2014-03-01

The biogeochemical behavior of heavy metals in contaminated excessively moistened soils depends on the development of reducing conditions (either moderate or strong). Upon the moderate biogenic reduction, Cr as the metal with variable valence forms low-soluble compounds, which decreases its availability to plants and prevents its penetration into surface- and groundwater. Creation of artificial barriers for Cr fixation on contaminated sites is based on the stimulation of natural metal-reducing bacteria. Arsenic, being a metalloid with a variable valence, is mobilized upon the moderate biogenic reduction. The mobility of siderophilic heavy metals with a constant valence grows under the moderate reducing conditions at the expense of dissolution of iron (hydr)oxides as carriers of these metals. Zinc, which can enter the newly formed goethite lattice, is an exception. Strong reduction processes in organic excessively moist and flooded soils (usually enriched in S) lead to the formation of low-soluble sulfides of heavy elements with both variable (As) and constant (Cu, Ni, Zn, and Pb) valence. On changing aquatic regime in overmoistened soils and their drying, sulfides of heavy metals are oxidized, and previously fixed metals are mobilized.

Estimation and comparison of potential runoff-contributing areas in Kansas using topographic, soil, and land-use information

USGS Publications Warehouse

Juracek, Kyle E.

2000-01-01

Digital topographic, soil, and land-use information was used to estimate potential runoff-contributing areas in Kansas. The results were used to compare 91 selected subbasins representing slope, soil, land-use, and runoff variability across the State. Potential runoff-contributing areas were estimated collectively for the processes of infiltration-excess and saturation-excess overland flow using a set of environmental conditions that represented, in relative terms, very high, high, moderate, low, very low, and extremely low potential for runoff. Various rainfall-intensity and soil-permeability values were used to represent the threshold conditions at which infiltration-excess overland flow may occur. Antecedent soil-moisture conditions and a topographic wetness index (TWI) were used to represent the threshold conditions at which saturation-excess overland flow may occur. Land-use patterns were superimposed over the potential runoff-contributing areas for each set of environmental conditions. Results indicated that the very low potential-runoff conditions (soil permeability less than or equal to 1.14 inches per hour and TWI greater than or equal to 14.4) provided the best statewide ability to quantitatively distinguish subbasins as having relatively high, moderate, or low potential for runoff on the basis of the percentage of potential runoff-contributing areas within each subbasin. The very low and (or) extremely low potential-runoff conditions (soil permeability less than or equal to 0.57 inch per hour and TWI greater than or equal to 16.3) provided the best ability to qualitatively compare potential for runoff among areas within individual subbasins. The majority of subbasins with relatively high potential for runoff are located in the eastern half of the State where soil permeability is generally less and precipitation is typically greater. The ability to distinguish subbasins as having relatively high, moderate, or low potential for runoff was possible mostly due to the variability of soil permeability across the State. The spatial distribution of potential contributing areas, in combination with the superimposed land-use patterns, may be used to help identify and prioritize subbasin areas for the implementation of best-management practices to manage runoff and meet Federally mandated total maximum daily load requirements.

Water movement through an experimental soil liner

USGS Publications Warehouse

Krapac, I.G.; Cartwright, K.; Panno, S.V.; Hensel, B.R.; Rehfeldt, K.R.; Herzog, B.L.

1991-01-01

A field-scale soil liner was constructed to test whether compacted soil barriers in cover and liner systems could be built to meet the U.S. EPA saturated hydraulic conductivity requirement (???1 x 10-7 cm s-1). The 8 x 15 x 0.9m liner was constructed in 15 cm compacted lifts using a 20,037 kg pad-foot compactor and standard engineering practices. Water infiltration into the liner has been monitored for one year. Monitoring will continue until water break through at the base of the liner occurs. Estimated saturated hydraulic conductivities were 2.5 x 10-9, 4.0 x 10-8, and 5.0 x 10-8 cm s-1 based on measurements of water infiltration into the liner by large- and small-ring infiltrometers and a water balance analysis, respectively. Also investigated in this research was the variability of the liner's hydraulic properties and estimates of the transit times for water and tracers. Small variances exhibited by small-ring flux data suggested that the liner was homogeneous with respect to infiltration fluxes. The predictions of water and tracer breakthrough at the base of the liner ranged from 2.4-12.6 y, depending on the method of calculation and assumptions made. The liner appeared to be saturated to a depth between 18 and 33 cm at the end of the first year of monitoring. Transit time calculations cannot be verified yet, since breakthrough has not occurred. The work conducted so far indicates that compacted soil barriers can be constructed to meet the saturated hydraulic conductivity requirement established by the U.S. EPA.A field-scale soil liner was constructed to test whether compacted soil barriers in cover and liner systems could be built to meet the U.S. EPA saturated hydraulic conductivity requirement (??? 1 ?? 10-7 cm s-1). The 8 ?? 15 ?? 0.9 m liner was constructed in 15 cm compacted lifts using a 20.037 kg pad-foot compactor and standard engineering practices. Water infiltration into the liner has been monitored for one year. Monitoring will continue until water break through at the base of the liner occurs. Estimated saturated hydraulic conductivities were 2.5 ?? 10-9, 4.0 ?? 10-8, and 5.0 ?? 10-8 cm s-1 based on measurements of water infiltration into the liner by large- and small-ring infiltrometers and a water balance analysis, respectively. Also investigated in this research was the variability of the liner's hydraulic properties and estimates of the transit times for water and tracers. Small variances exhibited by small-ring flux data suggested that the liner was homogeneous with respect to infiltration fluxes. The predictions of water and tracer breakthrough at the base of the liner ranged from 2.4-12.6 y, depending on the method of calculation and assumptions made. The liner appeared to be saturated to a depth between 18 and 33 cm at the end of the first year of monitoring. Transit time calculations cannot be verified yet, since breakthrough has not occurred. The work conducted so far indicates that compacted soil barriers can be constructed to meet the saturated hydraulic conductivity requirement established by the U.S. EPA.

Soil properties linked to Phytophthora cinnamomi presence and oak decline in Iberian dehesas

NASA Astrophysics Data System (ADS)

Moreno, G.; Vivas, M.; Pérez, A.; Cubera, E.; Madeira, M.; Solla, A.

2009-04-01

Dehesas cover about 3,100,000 ha in the Iberian Peninsula, and support an outstanding diversity of wildlife and flora endemisms. These open woodlands provide Spain and Portugal inhabitants with a high-quality food, derived from animal production, sustain rural population, and act as retardants of soil erosion and desertification, which are considered primary environmental concerns in the Mediterranean basin. Dehesas are considered examples of sustainable use, though in the last few decades intensive land use, imposed by a concomitant change in the technological and socio-economic conditions, and common agricultural policies threat their conservation. Soil compaction and erosion, oak regeneration failure, dieback of old-ageing stands, and loose of biodiversity are some of the most common threats. At the same time, a severe decline of Quercus ilex (Holm oak) has been reported since the 1990s in the southern Iberian Peninsula, and more recently in France, Italy, and Morocco. In the Iberian Peninsula, the decline has been mostly observed in dehesas, where a combination of factors, possibly acting in synergy, have been put forward to explain the disease. Severe drought episodes, flooding, and rapid fluctuations in soil water content have been reported as predisposing factors favoring tree invasion by bark borer insects and/or pathogenic fungi. It is mostly ignored to what extent decline is a natural or a man-induced process, and if it is associated to either basic, management-related soil properties, or both. To bring insight to this problem, extensive and integrative comparisons of some soil properties related to hydromorphism were initiated, comprising pairs of adjacent non-symptomatic and symptomatic Q. ilex trees. In 2008, 48 dehesa stands from western Spain (Cáceres), half of them located along stream banks and the other half located in slopes, were intensively studied. In each stand, soil and root samples were taken under 3 non-symptomatic (healthy) and 3 symptomatic (declined) trees, at surface, 50, 100 and 150 cm depths. Soil texture, redox potential, mineral N, and the presence of Phytophthora cinnamomi were determined. Soil bulk density was measured at the surface, and soil compactness was measured through a digital penetrometer at 0-40 cm depth. In the stream banks, fine-textured soils were significantly more common under declined trees than under healthy ones, while in slopes the contrary trend occurred. Differences were clearly observed at layers located at 100 and 150 cm depth. Soil bulk density was moderate, with mean values of 1.05 and 1.07 g cm-3 (0-5 cm depth), and 1.28 and 1.30 g cm-3 (5-10 cm) for healthy and declined oaks, respectively. Regarding soil resistance to penetration, values under declined oaks were significantly (p=0.012) higher below 20 cm depth, probably due to compaction caused by old cultivation practices. Most of the soil samples analyzed showed a high level of oxidation (superoxic and manoxic), 28% were suboxic and only 0.7% were anoxic, with a possible limitation of root growth. Although not significant, soils trended to be more reduced under declined oaks at stream banks, with a contrary tendency at slopes (Table 1). The presence of P. cinammomi in soil was positively related to oak decline in stream banks (p=0.011), but not in slopes, and associated to more compacted soils (p=0.05). The presence of P. cinammomi in roots was positively correlated with oak decay (p=0.01), being more abundant among 50-100 cm depth in slopes, and among 100-150 cm depth in the stream banks, but in both cases was mostly associated to fine-textured soils. In conclusion, Q. ilex decline was not related with anoxic conditions limiting root growth, but with soil properties leading to restricted water availability for trees in slopes, and with soil conditions favorable for P. cinnamomi root-infections in the stream banks.

Campsite conditions in the Bob Marshall Wilderness, Montana

Treesearch

David N. Cole

1983-01-01

The condition of campsites was examined in the Bob Marshall Wilderness, Montana. The amount of change that has occurred on these sites was inferred by comparing campsites with comparable control sites. Trampling disturbance - loss of vegetation, exposure of mineral soil, and compaction of the soil - was generally comparable to that found in other backcountry areas....

Soil compaction and chestnut ink disease

Treesearch

T.F. Fonseca; C.G. Abreu; B.R. Parresol

2004-01-01

Chestnut ink disease caused by the oomycete Phytophthora cinnamomi, a soil-borne pathogen of world-wide distribution, accounts for the majority of disease problems on chestnuts in Portugal, limiting yield in a large number of stands and impeding establishment of trees in new areas. A survey was carried out in 32 chestnut stands in the Padrela...

Impact of biomass harvesting on forest soil productivity in the northern Rocky Mountains

Treesearch

Woongsoon Jang; Christopher R. Keyes; Deborah Page-Dumroese

2015-01-01

Biomass harvesting extracts an increased amount of organic matter from forest ecosystems over conventional harvesting. Since organic matter plays a critical role in forest productivity, concerns of potential negative long-term impacts of biomass harvesting on forest productivity (i.e., changing nutrient/water cycling, aggravating soil properties, and compaction) have...

PROTOCOL FOR DETERMINING BIOAVAILABILITY AND BIOKINETICS OF ORGANIC POLLUTANTS IN DISPERSED, COMPACTED AND INTACT SOIL SYSTEMS TO ENHANCE IN SITU BIOREMEDIATION

EPA Science Inventory

The development of effective in situ and on-site bioremediation technologies can facilitate the cleanup of chemically-contaminated soil sites. Knowledge of biodegradation kinetics and bioavailability of organic pollutants can facilitate decisions on the efficacy of in situ and o...

Emissions of 1,3-dichloropropene and chloropicrin after soil fumigation under field conditions

USDA-ARS?s Scientific Manuscript database

Soil fumigation is an important agronomic practice in the production of many high-value vegetable and fruit crops. The use of soil fumigant chemicals can lead to excessive atmospheric emissions and information is needed to develop best management practices so that use of soil fumigants does not har...

Measurement of soil creep by inclinometer

Treesearch

Robert R. Ziemer

1977-01-01

Abstract - Continued inclinometer measurements at borehole sites installed in 1964 in northern California suggest that previously reported rates of soil creep are excessively high. Upon analysis of 35 access casings located in forested and grassland sites, no consistent direction of soil movement could be detected. In addition, no significant rate of soil creep could...

Effect of Soil Amendments on Cd accumulation by Spinach from a Cd-Mineralized Soil

USDA-ARS?s Scientific Manuscript database

Cadmium mineralized soils occur in many nations. When these soils are non-calcareous, crops and especially leafy vegetables such as lettuce and spinach accumulate levels of Cd which exceed international standards. Lockwood loam from Monterey Co., CA, has been found to cause excessive Cd in leafy veg...

Mountain bike trail compaction relation to selected physical parameters

Treesearch

Jeff Hale; Rodney R. Zwick

2002-01-01

The purpose of this research is to explore the rates of compaction and their relation to trail contextual aspects of: soil type, slope and crown cover on a newly established mountain bike trail in the northern reach of Vermont. A random sample of 52 sites was selected for monitoring on the 1.09-mile trail. Three penetrometer readings were taken at each of the sample...

DEMONSTRATION BULLETIN: ENVIROGARD™ PCB TEST KIT - MILLIPORE, INC.

EPA Science Inventory

The EnviroGard™ polychlorinated biphenyl (PCB) immunoassay test kit rapidly analyzes for PCB concentrations in soils. Soil sample extracts are added to test tubes coated with antibodies that bind PCB molecules. The excess soil extracts are washed out of the tubes after incubat...

Utilization and environmental management of residues from intensive animal production

USDA-ARS?s Scientific Manuscript database

Animal manures are traditional sources of nutrients in agriculture. Under proper management, manures provide nutrients to soil, reducing or eliminating the use of commercial fertilizers, as well as organic carbon that improves soil physical properties and soil health. However, excessive application ...

Soil fate of agricultural fumigants in raised-bed, plasticulture systems in the southeastern United States.

PubMed

Chellemi, Dan O; Ajwa, Husein A; Sullivan, David A; Alessandro, Rocco; Gilreath, James P; Yates, Scott R

2011-01-01

Soil concentrations and degradation rates of methyl isothio-cyanate (MITC), chloropicrin (CP), 1,3-dichloropropene (1,3-D), and dimethyl disulfide (DMDS) were determined under fumigant application scenarios representative of commercial raised bed, plastic mulched vegetable production systems. Five days after application, 1,3-D, MITC, and CP were detected at concentrations up to 3.52, 0.72, and 2.45 μg cm, respectively, in the soil atmosphere when applications were made in uniformly compacted soils with a water content >200% of field capacity and covered by a virtually impermeable or metalized film. By contrast, DMDS, MITC, and CP concentrations in the soil atmosphere were 0.81, 0.02, and 0.05 μg cm, respectively, 5 d after application in soil containing undecomposed plant residue, numerous large (>3 mm) clods, and water content below field capacity and covered by low-density polyethylene. Ranked in order of impact on the persistence of fumigants in soil were soil water content (moisture), soil tilth (the physical condition of soil as related to its fitness as a planting bed), the type of plastic film used to cover fumigated beds, and soil texture. Fumigants were readily detected 13 d after application when applied in uniformly compacted soils with water contents >200% of capacity and covered by a virtually impermeable or metalized film. By contrast, 1,3-D and MITC had dissipated 5 d after application in soils with numerous large (>3 mm) clods and water contents below field capacity that were covered by low-density polyethylene. Soil degradation of CP, DMDS, and MITC were primarily attributed to biological mechanisms, whereas degradation of 1,3-D was attributed principally to abiotic factors. This study demonstrates improved soil retention of agricultural fumigants in application scenarios representative of good agricultural practices. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Comparison of effects of cold-region soil/snow processes and the uncertainties from model forcing data on permafrost physical characteristics

DOE PAGES

Barman, Rahul; Jain, Atul K.

2016-03-28

Here, we used a land surface model to (1) evaluate the influence of recent improvements in modeling cold-region soil/snow physics on near-surface permafrost physical characteristics (within 0–3 m soil column) in the northern high latitudes (NHL) and (2) compare them with uncertainties from climate and land-cover data sets. Specifically, four soil/snow processes are investigated: deep soil energetics, soil organic carbon (SOC) effects on soil properties, wind compaction of snow, and depth hoar formation. In the model, together they increased the contemporary NHL permafrost area by 9.2 × 10 6 km 2 (from 2.9 to 12.3—without and with these processes, respectively)more » and reduced historical degradation rates. In comparison, permafrost area using different climate data sets (with annual air temperature difference of ~0.5°C) differed by up to 2.3 × 10 6 km 2, with minimal contribution of up to 0.7 × 10 6 km 2 from substantial land-cover differences. Individually, the strongest role in permafrost increase was from deep soil energetics, followed by contributions from SOC and wind compaction, while depth hoar decreased permafrost. The respective contribution on 0–3 m permafrost stability also followed a similar pattern. However, soil temperature and moisture within vegetation root zone (~0–1 m), which strongly influence soil biogeochemistry, were only affected by the latter three processes. The ecosystem energy and water fluxes were impacted the least due to these soil/snow processes. While it is evident that simulated permafrost physical characteristics benefit from detailed treatment of cold-region biogeophysical processes, we argue that these should also lead to integrated improvements in modeling of biogeochemistry.« less

Testing the Visual Soil Assessment tool on Estonian farm fields

NASA Astrophysics Data System (ADS)

Reintam, Endla; Are, Mihkel; Selge, Are

2017-04-01

Soil quality estimation plays important role in decision making on farm as well on policy level. Sustaining the production ability and good health of the soil the chemical, physical and biological indicators should be taken into account. The system to use soil chemical parameters is usually quite well established in most European counties, including Estonia. However, measuring soil physical properties, such bulk density, porosity, penetration resistance, structural stability ect is time consuming, needs special tools and is highly weather dependent. In that reason these parameters are excluded from controllable quality parameters in policy in Estonia. Within the project "Interactive Soil Quality Assessment in Europe and China for Agricultural Productivity and Environmental Resilience" (iSQAPER) the visual soil assessment (VSA) tool was developed for easy detection of soil quality as well the different soil friendly agricultural management practices (AMP) were detected. The aim of current study was to test the VSA tool on Estonian farm fields under different management practices and compare the results with laboratory measurements. The main focus was set on soil physical parameters. Next to the VSA, the undisturbed soil samples were collected from the depth of 5-10 cm and 25-30 cm. The study revealed that results of a visually assessed soil physical parameters, such a soil structure, soil structural stability, soil porosity, presence of tillage pan, were confirmed by laboratory measurements in most cases. Soil water stable structure measurement on field (on 1 cm2 net in one 1 l box with 4-6 cm air dry clods for 5-10 min) underestimated very well structured soil on grassland and overestimated the structure aggregates stability of compacted soil. The slightly better soil quality was detected under no-tillage compared to ploughed soils. However, the ploughed soil got higher quality points compared with minimum tillage. The slurry application (organic manuring) had controversial impact - it increased the number of earthworms but decreased soil structural stability. Even the manuring with slurry increases organic matter amount in the soil, the compaction due to the use of heavy machinery during the application, especially on wet soil, reduces the positive effect of slurry.

Compact high-flux two-stage solar collectors based on tailored edge-ray concentrators

NASA Astrophysics Data System (ADS)

Friedman, Robert P.; Gordon, Jeffrey M.; Ries, Harald

1995-08-01

Using the recently-invented tailored edge-ray concentrator (TERC) approach for the design of compact two-stage high-flux solar collectors--a focusing primary reflector and a nonimaging TERC secondary reflector--we present: 1) a new primary reflector shape based on the TERC approach and a secondary TERC tailored to its particular flux map, such that more compact concentrators emerge at flux concentration levels in excess of 90% of the thermodynamic limit; and 2) calculations and raytrace simulations result which demonstrate the V-cone approximations to a wide variety of TERCs attain the concentration of the TERC to within a few percent, and hence represent practical secondary concentrators that may be superior to corresponding compound parabolic concentrator or trumpet secondaries.

Effects of excess levels of a polymer as a soil conditioner on yields and mineral nutrition of plants. [Triticum aestivum; Lycopersicon esculentum

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

Wallace, A.; Wallace, G.A.; Abouzamzam, A.M.

Wheat (Triticum aestivum L. cv. INIA66R) and tomato (Lycopersicon esculentum Mill. cv. Tropic) were grown in containers with a Xerorthents soil and with levels of an anionic soil conditioner far in excess of that needed for adequate stabilization of soil. The 1% rate increased the vegetative growth of plants over controls, and the 5% rate gave yields more nearly like controls. The anionic polymer decreased accumulation of the anions P and Si in all plants and decreased Mn and B in wheat only. The highest level of polymer also depressed accumulation of some of the macroelement cations. Both levels ofmore » polymer created 100% water-stable aggregates compared with only 38% in the control. The potential for toxicity of polyacrylamide soil conditioners is discussed.« less

Bench and Riser Soil Water Content on Semiarid Hillslopes with Terracettes

NASA Astrophysics Data System (ADS)

Heinse, R.; Corrao, M.; Eitel, J.; Link, T. E.

2015-12-01

Microtopographic features known as terracettes are found throughout many semiarid rangelands. These path-like features roughly perpendicular to the slope are frequently traversed by grazing animals on steep hillslopes. The soil properties and hydrologic function, however, are virtually unknown. This research aimed to identify differences in soil properties between terracette bench and riser features, and their influence on soil water content for two terracetted sites and two non-terracetted control sites (grazed and ungrazed) in Eastern Washington State. Measurements of volumetric water content (θ_v), bulk density, soil texture, saturated hydraulic conductivity, pH, and ECa_a were collected along with compaction, vegetative cover and cattle density throughout the 2013 and 2014 field seasons. Results show small but significant volumetric water content differences between terracette benches and risers in the upper 10 cm with benches exhibiting higher mean θ_v than risers throughout the year. Soil bulk density on benches (1600 kg m-3^{-3}) was significantly higher than that of risers (1300 kg m-3^{-3}) with no differences in soil texture. The saturated hydraulic conductivity on benches was roughly half of that for risers. No significant soil differences were noted below 20 cm depth. Terracetted sites showed greater field-averaged θ_v compared to non-terracetted sites suggesting a positive trend with animal stocking rates. Higher water content on terracette benches is attributed to shifts in pore size distribution with compaction, and a reduction in root-water uptake due to plant-root impedance. This increased soil water does not however increase forage production as it is not accessible to plants.

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.

Laboratory study on subgrade soil stabilization using RBI grade 81

NASA Astrophysics Data System (ADS)

Cynthia, J. Bernadette; Kamalambikai, B.; Prasanna Kumar, R.; Dharini, K.

2017-07-01

The present study investigates the effect of reinforcing the sub grade soils with RBI 81 material. A soil nearby was collected and preliminary tests were conducted to classify the soil and it was found from the results that the sample collected was a poorly graded clay. Subsequently Tests such as Proctor Compaction, CBR, and UCC were conducted to study the various engineering properties of the identified soil. In addition to the above tests were also conducted on the soil by reinforcing with varying percentages of RBI 81. From the analysis of test results it was found that this material (RBI 81) will significantly improve the CBR value of the soil.

Investigation of guided wave propagation and attenuation in pipe buried in sand

NASA Astrophysics Data System (ADS)

Leinov, Eli; Lowe, Michael J. S.; Cawley, Peter

2015-07-01

Long-range guided wave testing is a well-established method for detection of corrosion defects in pipelines. The method is currently used routinely for above ground pipelines in a variety of industries, e.g. petrochemical and energy. When the method is applied to pipes buried in soil, test ranges tend to be significantly compromised and unpredictable due to attenuation of the guided wave resulting from energy leakage into the embedding soil. The attenuation characteristics of guided wave propagation in an 8 in. pipe buried in sand are investigated using a laboratory full-scale experimental rig and model predictions. We report measurements of attenuation of the T(0,1) and L(0,2) guided wave modes over a range of sand conditions, including loose, compacted, mechanically compacted, water saturated and drained. Attenuation values are found to be in the range of 1.65-5.5 dB/m and 0.98-3.2 dB/m for the torsional and longitudinal modes, respectively, over the frequency of 11-34 kHz. The application of overburden pressure modifies the compaction of the sand and increases the attenuation. Mechanical compaction of the sand yields similar attenuation values to those obtained with applied overburden pressure. The attenuation decreases in the fully water-saturated sand, and increases in drained sand to values comparable with those obtained for compacted sand. Attenuation measurements are compared with Disperse software model predictions and confirm that the attenuation phenomenon in buried pipes is essentially governed by the bulk shear velocity in the sand. The attenuation behaviour of the torsional guided wave mode is found not to be captured by a uniform soil model; comparison with predictions obtained with the Disperse software suggest that this is likely to be due to a layer of sand adhering to the surface of the pipe.

AO corrected satellite imaging from Mount Stromlo

NASA Astrophysics Data System (ADS)

Bennet, F.; Rigaut, F.; Price, I.; Herrald, N.; Ritchie, I.; Smith, C.

2016-07-01

The Research School of Astronomy and Astrophysics have been developing adaptive optics systems for space situational awareness. As part of this program we have developed satellite imaging using compact adaptive optics systems for small (1-2 m) telescopes such as those operated by Electro Optic Systems (EOS) from the Mount Stromlo Observatory. We have focused on making compact, simple, and high performance AO systems using modern high stroke high speed deformable mirrors and EMCCD cameras. We are able to track satellites down to magnitude 10 with a Strehl in excess of 20% in median seeing.

Active Plasma Lensing for Relativistic Laser-Plasma-Accelerated Electron Beams

DOE PAGES

van Tilborg, J.; Steinke, S.; Geddes, C. G. R.; ...

2015-10-28

The compact, tunable, radially symmetric focusing of electrons is critical to laser-plasma accelerator (LPA) applications. Experiments are presented demonstrating the use of a discharge-capillary active plasma lens to focus 100-MeV-level LPA beams. The lens can provide tunable field gradients in excess of 3000 T/m, enabling cm-scale focal lengths for GeV-level beam energies and allowing LPA-based electron beams and light sources to maintain their compact footprint. For a range of lens strengths, excellent agreement with simulation was obtained.

Nitrogen excess in North American ecosystems: predisposing factors, ecosystem responses, and management strategies

Treesearch

Mark E. Fenn; Mark A. Poth; John D. Aber; Jill S. Baron; Bernard T. Bormann; Dale W. Johnson; A. Dennis Lemly; Steven G. McNulty; Douglas F. Ryan; Robert Stottlemyer

1998-01-01

Most forests in North America remain nitrogen limited, although recent studies have identified forested areas that exhibit symptoms of N excess, analogous to overfertilization of arable land. Nitrogen excess in watersheds is detrimental because of disruptions in plantlsoil nutrient relations, increased soil acidification and aluminum mobility, increased emissions of...

SOIL CADMIUM AS A THREAT TO HUMAN HEALTH

EPA Science Inventory

Cd contamination of soils has been a public concern since the demonstration that soil Cd from Zn mine wastes which contaminated rice paddies had caused excessive Cd absorption and adverse health effects in members of subsistence farm families who consumed rice grown on the contam...

Shaping an Optimal Soil by Root-Soil Interaction.

PubMed

Jin, Kemo; White, Philip J; Whalley, William R; Shen, Jianbo; Shi, Lei

2017-10-01

Crop production depends on the availability of water and mineral nutrients, and increased yields might be facilitated by a greater focus on roots-soil interactions. Soil properties affecting plant growth include drought, compaction, nutrient deficiency, mineral toxicity, salinity, and submergence. Plant roots respond to the soil environment both spatially and temporally by avoiding stressful soil environments and proliferating in more favorable environments. We observe that crops can be bred for specific root architectural and biochemical traits that facilitate soil exploration and resource acquisition, enabling greater crop yields. These root traits affect soil physical and chemical properties and might be utilized to improve the soil for subsequent crops. We argue that optimizing root-soil interactions is a prerequisite for future food security. Copyright © 2017 Elsevier Ltd. All rights reserved.

Soil diagnosis of an urban settlement with low levels of anthropogenic pollution (Stepnoe, Saratov region)

NASA Astrophysics Data System (ADS)

Ngun, C. T.; Pleshakova, Ye V.; Reshetnikov, M. V.

2018-01-01

A soil diagnosis of an urban territory Stepnoe (Saratov region) was conducted within the framework of soil research monitoring of inhabited localities with low levels of anthropogenic impact using chemical and microbiological analysis. Excess over maximum permissible concentration (MPC) of mobile forms of Cr, Zn and Cd were not observed within the researched territory. A universal excess over MPC of mobile forms of Ni, Cu and Pb was established which is most likely connected with anthropogenic contamination. It was discovered that, at the territory of the Stepnoe settlement, mobile forms of heavy metals compounds (HM) in most cases formed paragenetic associations with high correlation coefficient and despite this, an excess over MPC was not significant. This point to a common mineralogical origin of the elements inherited from the parent rock. The values of the total index of chemical contamination were not above 16, which puts the researched samples in a category with permissible contamination. The indices of the total number of heterotrophic bacteria, iron-oxidizing and hydrocarbon-oxidizing bacteria in most samples corresponded to normal indices for chestnut solonetsous and saline soils. In some samples, a deviation from the normal indices was observed justifying the impact of specific contaminants on the soil.

Radionuclide concentrations in soil and lifetime cancer risk due to gamma radioactivity in Kirklareli, Turkey.

PubMed

Taskin, H; Karavus, M; Ay, P; Topuzoglu, A; Hidiroglu, S; Karahan, G

2009-01-01

The objective of this study is to evaluate and map soil radionuclides' activity concentrations and environmental outdoor gamma dose rates (terrestrial and cosmic) in Kirklareli, Turkey. The excess lifetime cancer risks are also calculated. Outdoor gamma dose rates were determined in 230 sampling stations and soil samples were taken from 177 locations. The coordinates of the readings were determined by the Global Positioning System (GPS). The outdoor gamma dose rates were determined by Eberline smart portable device (ESP-2) and measurements were taken in air for two minutes at 1m from the ground. The average outdoor gamma dose rate was 118+/-34nGyh(-1). Annual effective gamma dose of Kirklareli was 144microSv and the excess lifetime cancer risk of 5.0x10(-4). Soil samples were analyzed by gamma spectroscopy. The average 226Ra, 238U, 232Th, 137Cs, and 40K activities were 37+/-18Bqkg(-1), 28+/-13Bqkg(-1), 40+/-18Bqkg(-1), 8+/-5Bqkg(-1) and 667+/-281Bqkg(-1), respectively. The average soil radionuclides' concentrations of Kirklareli were within the worldwide range although some extreme values had been determined. Annual effective gamma doses and the excess lifetime risks of cancer were higher than the world's average.

Deep soil compaction as a method of ground improvement and to stabilization of wastes and slopes with danger of liquefaction, determining the modulus of deformation and shear strength parameters of loose rock.

PubMed

Lersow, M

2001-01-01

For the stabilization of dumps with the construction of hidden dams and for building ground improvement, for instance for traffic lines over dumps, nearly all applied compaction methods have the aim to reduce the pore volume in the loose rock. With these methods, a homogenization of the compacted loose rock will be obtained too. The compaction methods of weight compaction by falling weight, compaction by vibration and compaction by blasting have been introduced, and their applications and efficiencies have been shown. For the estimation of the effective depth of the compaction and for a safe planning of the bearing layer, respectively, the necessary material parameters have to be determined for each deep compaction method. Proposals for the determination of these parameters have been made within this paper. In connection with the stabilization of flow-slide-prone dump slopes, as well as for the improvement of dump areas for the use as building ground, it is necessary to assess the deformation behavior and the bearing capacity. To assess the resulting building ground improvement, deformation indexes (assessment of the flow-prone layer) and strength indexes (assessment of the bearing capacity) have to be determined with soil mechanical tests. Förster and Lersow, [Patentschrift DE 197 17 988. Verfahren, auf der Grundlage last- und/oder weggesteuerter Plattendruckversuche auf der Bohrlochsohle, zur Ermittlung des Spannungs-Verformungs-Verhaltens und/oder von Deformationsmoduln und/oder von Festigkeitseigenschaften in verschiedenen Tiefen insbesondere von Lockergesteinen und von Deponiekörpern in situ; Förster W, Lersow M. Plattendruckversuch auf der Bohrlochsohle, Ermittlung des Spannungs-Verformungs-Verhaltens von Lockergestein und Deponiematerial Braunkohle--Surface Mining, 1998;50(4): 369-77; Lersow M. Verfahren zur Ermittlung von Scherfestigkeitsparametern von Lockergestein und Deponiematerial aus Plattendruckversuchen auf der Bohrlochsohle. Braunkohle--Surface Mining, 1995;51(1):39-47] improved a direct procedure, the so-called plate-loading test. With this improved procedure, it is possible to produce profiles of deformation parameters and shear-strength parameters of the loose rock. On this basis the settlement behavior and the bearing behavior of the ground can be described. The PDV-BS cone-penetration test and the pressiometer test are compared and the reliability of the soil mechanical indexes are assessed critically. The PDV-BS can be used as a calibration test for cone penetration tests as well as for the calibration of pressiometer tests. With the application of a PDV-BS and a pressiometer test in combination in a testing field, the anisotropy properties of the loose rock can be proved.

Preliminary Guidelines and Standard Operating Procedure for Drainage and Erosion Control at McMurdo Station

DTIC Science & Technology

2014-12-01

along the impermeable frozen soil layer. Soil freeze–thaw action disrupts soil structures, displaces soils particles , and creates voids both in...discharging along the bank face). This was caused by excess pore water pressure. Soil piping removes soil particles from their in-situ position, leaving...soil particles ERDC/CRREL SR-14-3 30 c. Maintain original side and bed slopes during the clearing efforts. d. Shape the channels to minimize

Lateral fluid flow in a compacting sand-shale sequence: South Caspian basin.

USGS Publications Warehouse

Bredehoeft, J.D.; Djevanshir, R.D.; Belitz, K.R.

1988-01-01

The South Caspian basin contains both sands and shales that have pore-fluid pressures substantially in excess of hydrostatic fluid pressure. Pore-pressure data from the South Caspian basin demonstrate that large differences in excess hydraulic head exist between sand and shale. The data indicate that sands are acting as drains for overlying and underlying compacting shales and that fluid flows laterally through the sand on a regional scale from the basin interior northward to points of discharge. The major driving force for the fluid movement is shale compaction. We present a first- order mathematical analysis in an effort to test if the permeability of the sands required to support a regional flow system is reasonable. The results of the analysis suggest regional sand permeabilities ranging from 1 to 30 md; a range that seems reasonable. This result supports the thesis that lateral fluid flow is occurring on a regional scale within the South Caspian basin. If vertical conduits for flow exist within the basin, they are sufficiently impermeable and do not provide a major outlet for the regional flow system. The lateral fluid flow within the sands implies that the stratigraphic sequence is divided into horizontal units that are hydraulically isolated from one another, a conclusion that has important implications for oil and gas migration.-Authors

In-situ Mass Distribution Quotient (iMDQ) - A New Factor to Compare Bioavailability of Pesticides in Soils?

NASA Astrophysics Data System (ADS)

Schroll, R.; Folberth, C.; Scherb, H.; Suhadolc, M.; Munch, J. C.

2009-04-01

Aim of this work was the development of a new non-biological factor to determine microbial in-situ bioavailability of chemicals in soils. Pesticide residues were extracted from ten highly different agricultural soils that had been incubated with the 14C-herbicide isoproturon (IPU) under comparable soil conditions (water tension - 15 kPa; soil density 1.3 g cm 3). Two different pesticide extraction approaches were compared: (i) 14C-Pesticide residues were measured in the pore water (PW) which was extracted from soil by centrifugation; (ii) 14C-Pesticide residues were extracted from soil samples with an excess of water (EEW). We introduce the pesticide's in-situ mass distribution quotient (iMDQ) as a measure for pesticide bioavailability, which is calculated as a quotient of adsorbed and dissolved chemical amounts for both approaches (iMDQPW, iMDQEEW). Pesticide mineralization in soils served as a reference for real microbial availability. A highly significant correlation between iMDQPW and mineralization showed that pore water extraction is adequate to assess IPU bioavailability. In contrast, no correlation exists between IPU mineralization and its extractability from soil with an excess of water. Therefore, it can be concluded that soil equilibration at comparable conditions and subsequent pore water extraction is vital for a isoproturon bioavailability ranking of soils.

Soil erosion transport through multiple rainfall events in the presence of stone cover: Laboratory flume experiments and analysis with the Hairsine-Rose model

NASA Astrophysics Data System (ADS)

Jomaa, S.; Barry, D. A.; Brovelli, A.; Heng, B. P.; Sander, G. C.; Parlange, J.

2011-12-01

Soil erosion is a major environmental problem that can lead to loss of fertility and degradation of agricultural fields. In order to develop efficient strategies to mitigate the impact of precipitation and reduce the erosion rate, a process-based understanding of the mechanisms that govern sediment transport and delivery is necessary. Soil state and physical properties prior to a precipitation event can affect significantly the erosion rate. Among the most important soil variables are moisture content, compaction and infiltration capacity. Additionally, the presence of stones on the topsoil surface retards the overland flow discharge, reduces runoff generation as well as the sediment delivery and prevents the development of a surface seal, which in turn maintains the infiltration rate. The aim of this study was to examine in detail the effect of surface stones, soil compaction and sealing for a sequence of rainfall events on soil erosion. Experiments were conducted using the EPFL erosion flume, which was divided into two identical flumes (one with stone and one without). The experiment involved four rainfall events with the precipitation rates: 28, 74, 74 and 28 mm h-1. After each 2-h event, the soil was allowed to air dry for 22 h. The total sediment concentration, the concentration of seven sediment size classes and the flow discharge were measured during each event at the outlet of each flume. Experimental results were analyzed using the Hairsine and Rose (H-R) soil erosion model. Results showed that (i) within each precipitation event, the proportion of each size class for the bare/stone-covered flume pairs at steady state were similar, whereas the initial response differed significantly; (ii) in all cases the effluent was enriched in finer particles relative to the original soil; and (iii) the effluent sediment composition was different from that of the original soil, and there was no clear trend towards the parent soil sediment size composition with time. The H-R model was able to reproduce well the events with high precipitation rate (events 2 and 3) with the same parameter set, while the match was less satisfactory for the low precipitation events. A possible explanation for this is that the initial soil compaction/sealing/development of the deposited layer combined to yield a surface that eroded similarly for identical rainfall conditions. Changes in the precipitation rate modifies the soil surface (the deposited layer in particular) and thus the erosion rates. Model application further suggested that over the course of the rainfall events, the contribution of the original soil to the eroded sediment decreased gradually, while that of the deposited layer increased.

Restoring ecosystem resilience to urban forests using Dutch elm disease-tolerant American elm trees

Treesearch

Charles E. Flower; Cornelia C. Pinchot; James M. Slavicek

2017-01-01

Urban forests contribute significantly to human health and environmental quality (Sanesi et al. 2011). As such, maintaining healthy urban forests resilient to pollution (atmospheric and soil), high temperatures, compacted soils, and poor drainage is critical. However, these forests have been hard hit by development, pests, and pathogens, consequently reshaping their...

A Rapid Soils Analysis Kit

DTIC Science & Technology

2008-03-01

behavior of moisture content-dry density Proctor curves......................................... 16 Figure 8. Moisture- density data scatter for an... density . Built-in higher order regression equations allow the user to visua- lize complete curves for Proctor density , as-built California Bearing Ratio...requirements involving soil are optimum moisture content (OMC) and maximum dry density (MDD) as determined from a laboratory compaction or Proctor test

Soil Compaction Absent in Plantation Thinning

Treesearch

Tony King; Sharon Haines

1979-01-01

We examine the effects on soil bulk density by using a TH-105 Thinner Harvester and two forwarders in a mechanically thinned slash pine (Pinus elliottii Engelm.) plantation. Points in the machine tracks were sampled before and after harvesting at depths of 5 and 10 cm (2 and 4 in) for moisture and bulk density. Both the standard gravimetric method...

Harvest intensity and competition control impacts on loblolly pine fusiform rust incidence

Treesearch

Robert J. Eaton; Paula Spaine; Felipe G. Sanchez

2006-01-01

The Long Term Soil Productivity experiment tests the effects of soil compaction, surface organic matter removal, and understory control on net primary productivity. An unintended consequence of these treatments may be an effect on the incidence of fusiform rust [Cronartium quercuum (Berk.) Miy. ex Shirai f. sp. fusiforme Burdsall et Snow]. Loblolly pine (Pinus...

Longleaf and loblolly pine seedlings respond differently to soil compaction, water content, and fertilization

Treesearch

D. Andrew Scott; James A. Burger

2014-01-01

Aims Longleaf pine (Pinus palustris Mill.) is being restored across the U.S. South for a multitude of ecological and economic reasons, but our understanding of longleaf pine’s response to soil physical conditions is poor. On the contrary, our understanding of loblolly pine (Pinus taeda L.) root and...

Design of a Horizontal Penetrometer for Measuring On-the-Go Soil Resistance

PubMed Central

Topakci, Mehmet; Unal, Ilker; Canakci, Murad; Celik, Huseyin Kursat; Karayel, Davut

2010-01-01

Soil compaction is one of the main negative factors that limits plant growth and crop yield. Therefore, it is important to determine the soil resistance level and map it for the field to find solutions for the negative effects of the compaction. Nowadays, high powered communication technology and computers help us on this issue within the approach of precision agriculture applications. This study is focused on the design of a penetrometer, which can make instantaneous soil resistance measurements in the soil horizontally and data acquisition software based on the GPS (Global Positioning System). The penetrometer was designed using commercial 3D parametric solid modelling design software. The data acquisition software was developed in Microsoft Visual Basic.NET programming language. After the design of the system, manufacturing and assembly of the system was completed and then a field experiment was carried out. According to the data from GPS and penetration resistance values which are collected in Microsoft SQL Server database, a Kriging method by ArcGIS was used and soil resistance was mapped in the field for a soil depth of 40 cm. During operation, no faults, either in mechanical and software parts, were seen. As a result, soil resistance values of 0.2 MPa and 3 MPa were obtained as minimum and maximum values, respectively. In conclusion, the experimental results showed that the designed system works quite well in the field and the horizontal penetrometer is a practical tool for providing on-line soil resistance measurements. This study contributes to further research for the development of on-line soil resistance measurements and mapping within the precision agriculture applications. PMID:22163410

Improvements of the Profil Cultural Method for a better Low-tech Field Assessment of Soil Structure under no-till

NASA Astrophysics Data System (ADS)

Roger-Estrade, Jean; Boizard, Hubert; Peigné, Josephine; Sasal, Maria Carolina; Guimaraes, Rachel; Piron, Denis; Tomis, Vincent; Vian, Jean-François; Cadoux, Stephane; Ralisch, Ricardo; Filho, Tavares; Heddadj, Djilali; de Battista, Juan; Duparque, Annie

2016-04-01

In France, agronomists have studied the effects of cropping systems on soil structure, using a field method based on a visual description of soil structure. The "profil cultural" method (Manichon and Gautronneau, 1987) has been designed to perform a field diagnostic of the effects of tillage and compaction on soil structure dynamics. This method is of great use to agronomists improving crop management for a better preservation of soil structure. However, this method was developed and mainly used in conventional tillage systems, with ploughing. As several forms of reduced, minimum and no tillage systems are expanding in many parts of the world, it is necessary to re-evaluate the ability of this method to describe and interpret soil macrostructure in unploughed situations. In unploughed fields, soil structure dynamics of untilled layers is mainly driven by compaction and regeneration by natural agents (climatic conditions, root growth and macrofauna) and it is of major importance to evaluate the importance of these natural processes on soil structure regeneration. These concerns have led us to adapt the standard method and to propose amendments based on a series of field observations and experimental work in different situations of cropping systems, soil types and climatic conditions. We improved the description of crack type and we introduced an index of biological activity, based on the visual examination of clods. To test the improved method, a comparison with the reference method was carried out and the ability of the "profil cultural" method to make a diagnosis was tested on five experiments in France, Brazil and Argentina. Using the improved method, the impact of cropping systems on soil functioning was better assessed when natural processes were integrated into the description.

Design of a horizontal penetrometer for measuring on-the-go soil resistance.

PubMed

Topakci, Mehmet; Unal, Ilker; Canakci, Murad; Celik, Huseyin Kursat; Karayel, Davut

2010-01-01

Soil compaction is one of the main negative factors that limits plant growth and crop yield. Therefore, it is important to determine the soil resistance level and map it for the field to find solutions for the negative effects of the compaction. Nowadays, high powered communication technology and computers help us on this issue within the approach of precision agriculture applications. This study is focused on the design of a penetrometer, which can make instantaneous soil resistance measurements in the soil horizontally and data acquisition software based on the GPS (Global Positioning System). The penetrometer was designed using commercial 3D parametric solid modelling design software. The data acquisition software was developed in Microsoft Visual Basic.NET programming language. After the design of the system, manufacturing and assembly of the system was completed and then a field experiment was carried out. According to the data from GPS and penetration resistance values which are collected in Microsoft SQL Server database, a Kriging method by ArcGIS was used and soil resistance was mapped in the field for a soil depth of 40 cm. During operation, no faults, either in mechanical and software parts, were seen. As a result, soil resistance values of 0.2 MPa and 3 MPa were obtained as minimum and maximum values, respectively. In conclusion, the experimental results showed that the designed system works quite well in the field and the horizontal penetrometer is a practical tool for providing on-line soil resistance measurements. This study contributes to further research for the development of on-line soil resistance measurements and mapping within the precision agriculture applications.

Hydrologic behavior of model slopes with synthetic water repellent soils

NASA Astrophysics Data System (ADS)

Zheng, Shuang; Lourenço, Sérgio D. N.; Cleall, Peter J.; Chui, Ting Fong May; Ng, Angel K. Y.; Millis, Stuart W.

2017-11-01

In the natural environment, soil water repellency decreases infiltration, increases runoff, and increases erosion in slopes. In the built environment, soil water repellency offers the opportunity to develop granular materials with controllable wettability for slope stabilization. In this paper, the influence of soil water repellency on the hydrological response of slopes is investigated. Twenty-four flume tests were carried out in model slopes under artificial rainfall; soils with various wettability levels were tested, including wettable (Contact Angle, CA < 90°), subcritical water repellent (CA ∼ 90°) and water repellent (CA > 90°). Various rainfall intensities (30 mm/h and 70 mm/h), slope angles (20° and 40°) and relative compactions (70% and 90%) were applied to model the response of natural and man-made slopes to rainfall. To quantitatively assess the hydrological response, a number of measurements were made: runoff rate, effective rainfall rate, time to ponding, time to steady state, runoff acceleration, total water storage and wetting front rate. Overall, an increase in soil water repellency reduces infiltration and shortens the time for runoff generation, with the effects amplified for high rainfall intensity. Comparatively, the slope angle and relative compaction had only a minor contribution to the slope hydrology. The subcritical water repellent soils sustained infiltration for longer than both the wettable and water repellent soils, which presents an added advantage if they are to be used in the built environment as barriers. This study revealed substantial impacts of man-made or synthetically induced soil water repellency on the hydrological behavior of model slopes in controlled conditions. The results shed light on our understanding of hydrological processes in environments where the occurrence of natural soil water repellency is likely, such as slopes subjected to wildfires and in agricultural and forested slopes.

Protocol for Cohesionless Sample Preparation for Physical Experimentation

DTIC Science & Technology

2016-05-01

protocol for specimen preparation that will enable the use of soil strength curves based on expedient field classification testing (e.g., grain-size...void ratio and relative compaction, which compares field compaction to a laboratory maximum density. Gradation charts for the two materials used in...the failure stress. Ring shear testing was performed using the GCTS Residual-Ring Shear System SRS-150 in order to measure the peak torsional

Investigation of the daytime lunar atmosphere

NASA Technical Reports Server (NTRS)

Hodges, R. R., Jr.

1985-01-01

Lunar atmosphere research has tended to center on gases with predictably large sources and on those which have been identified by Apollo experiments. An early candidate atmospheric constituent was Ar 40 which was noted by Heyman and Yaniv to have a surface correlated component in returned soil samples, and an abundance in excess of what can be explained by potassium decay. The source of the excess argon was attributed to atmospheric argon ions which have been accelerated by solar wind fields and implanted in soil grains.

Test to Extract Soil Properties Using the Seismic HammerTM Active Seismic Source

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

Lee, Rebekah F.; Abbott, Robert E.

Geologic material properties are necessary parameters for ground motion modeling and are difficult and expensive to obtain via traditional methods. Alternative methods to estimate soil properties require a measurement of the ground's response to a force. A possible method of obtaining these measurements is active-source seismic surveys, but measurements of the ground response at the source must also be available. The potential of seismic sources to obtain soil properties is limited, however, by the repeatability of the source. Explosives, and hammer surveys are not repeatable because of variable ground coupling or swing strength. On the other hand, the Seismic Hammermore » TM (SH) is consistent in the amount of energy it inputs into the ground. In addition, it leaves large physical depressions as a result of ground compaction. The volume of ground compaction varies by location. Here, we hypothesize that physical depressions left in the earth by the SH correlate to energy recorded by nearby geophones, and therefore are a measurement of soil physical properties. Using measurements of the volume of shot holes, we compare the spatial distribution of the volume of ground compacted between the different shot locations. We then examine energy recorded by the nearest 50 geophones and compare the change in amplitude across hits at the same location. Finally, we use the percent difference between the energy recorded by the first and later hits at a location to test for a correlation to the volume of the shot depressions. We find that: * Ground compaction at the shot-depression does cluster geographically, but does not correlate to known surface features. * Energy recorded by nearby geophones reflects ground refusal after several hits. * There is no correlation to shot volume and changes in energy at particular shot locations. Deeper material properties (i.e. below the depth of surface compaction) may be contributing to the changes in energy propagation. * Without further processing of the data, shot-depression volumes are insufficient to understanding ground response to the SH. Without an accurate understanding of the ground response, we cannot extract material properties in conjunction with the SH survey. Additional processing including picking direct arrivals and static corrections may yield positive results.« less

Laboratory investigation of TerraZyme as a soil stabilizer

NASA Astrophysics Data System (ADS)

Yusoff, Siti Aimi Nadia Mohd; Azmi, Mastura; Ramli, Harris; Bakar, Ismail; Wijeyesekera, D. C.; Zainorabidin, Adnan

2017-10-01

In this study, a laboratory investigation was conducted to examine the performance of TerraZyme on different soil types. Laterite and kaolin were treated with 2% and 5% TerraZyme to determine changes in the soils' geotechnical properties. The obtained results were analysed and investigated in terms of compaction, Unconfined Compressive Strength (UCS) and California Bearing Ratio (CBR). The changes in geotechnical properties of the stabilised and unstabilised soils were monitored after curing periods of 0, 7, 15, 21 and 30 days. Changes in compaction properties, UCS and CBR were observed. It was found that laterite with 5% TerraZyme gave a higher maximum dry density (MDD) and decreased the optimum moisture content (OMC). For kaolin, a different TerraZyme percentage did not show any effect on both MDD and OMC. For strength properties, it was found that 2% TerraZyme showed the greatest change in UCS over a 30-day curing period. The CBR value of stabilised kaolin with 2% TerraZyme gave a higher CBR value than the kaolin treated with 5% TerraZyme. It was also found that laterite treated with TerraZyme gave a higher CBR value. Lastly, it can be concluded that TerraZyme is not suitable for stabilising kaolin; TerraZyme requires a cohesive soil to achieve a better performance.

Biogeosystem technique - the fundamental base of modern Water Policy and Management

NASA Astrophysics Data System (ADS)

Kalinitchenko, Valery; Batukaev, Abdulmalik; Minkina, Tatiana; Solntseva, Natalia; Skovpen, Andrey; Zarmaev, Ali; Jusupov, Vaha; Lohmanova, Olga

2014-05-01

Freshwater conservation is the problem of world water strategy. Water is intended not only for human consumption but also for functions of the biosphere - the only place where humanity can exist. To maintain the quality of biosphere is very relevant. An important property of biosphere is ability of soil to provide the synthesis of fresh living biological material by plants. There are few places in the world where exists a natural high level of biological production. Therefore, irrigation widely applies. Irrigation provides an increase of crops, but the imitating gravitational frontal isotropic-continual irrigation paradigm has the adverse effects on soils and landscapes. So irrigation in the past history of humanity was one of the causes for civilization's downfall, Sumer in particular, now irrigation causes a humanitarian catastrophe in Central Asia. Irrigation is the world main consumer of water. Leading cause of negative results of irrigation in biosphere is the irrigation paradigm defect. By artificial watering is imitated a natural hydrological regime of the land. The water flows down into soil through the soil surface. Or groundwater flows up through the soil bottom. In either case, a natural or standard artificial soil moisturizing amplifies the mass transfer in soil continuum. At initial soil stage the mass transfer in soil continuum plays positive role. Adverse substances are leached, in particular soluble salts. Fine material and organic particles determining soil fertility are accumulating. However, after a soil genesis initial stage the mass transfer through soil continuum plays negative role. Irrigation excess water flow into soil reduces the productivity of cultivated plants as compared to the optimum soil solution conditions. The excess soil moisture leads to excess transpiration, evaporation, infiltration, destroys the soil disperse system composition, forms inactive dead-end pores, leaches useful biological and other substances synthesized in soil out from active biosphere stage to vadose zone. These substances are entering the undesired stage of sedimentation and lithogenesis. Such adverse events are enhanced by irrigation. As a result, up to 80-90% of the fresh water taken for irrigation from lakes, rivers, storage reservoirs, desalinators are lost useless entailing economic losses. As a result of irrigation the quality of water is deteriorated as well as the quality of soil and landscape. A quality of human environment and a quality of biosphere as a whole is reduced. It is much more dangerous than economic losses. The irrigation paradigm shift is essential for successful water policy and water management in modern world. In a framework of Biogeosystem technics the new intrasoil pulse continuous-discrete paradigm of irrigation is developed. Water is supplied by small discrete portions into individual volumes of a soil continuum without excess soil mass transfer, transpiration, evaporation and seepage. New paradigm of irrigation optimizes plant growth, reduces consumption of water per unit of biological product, the yield increases. It provides the soil and landscape conservation, fresh water - the global deficit - saving up to 10-20 times, biological productivity and sustainability of biosphere. Intrasoil pulse continuous-discrete robotic irrigation technologies match the nowadays noosphere technological platform.

Experimentally validated computational modeling of organic binder burnout from green ceramic compacts

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

Ewsuk, K.G.; Cochran, R.J.; Blackwell, B.F.

The properties and performance of a ceramic component is determined by a combination of the materials from which it was fabricated and how it was processed. Most ceramic components are manufactured by dry pressing a powder/binder system in which the organic binder provides formability and green compact strength. A key step in this manufacturing process is the removal of the binder from the powder compact after pressing. The organic binder is typically removed by a thermal decomposition process in which heating rate, temperature, and time are the key process parameters. Empirical approaches are generally used to design the burnout time-temperaturemore » cycle, often resulting in excessive processing times and energy usage, and higher overall manufacturing costs. Ideally, binder burnout should be completed as quickly as possible without damaging the compact, while using a minimum of energy. Process and computational modeling offer one means to achieve this end. The objective of this study is to develop an experimentally validated computer model that can be used to better understand, control, and optimize binder burnout from green ceramic compacts.« less

Inorganic fertilizers after broiler litter amendment reduce surplus nutrients in orchardgrass soils

USDA-ARS?s Scientific Manuscript database

The common producer practice to dispose of broiler litter at high rates to forage crops allow excessive accumulation of soil nutrients. A remediation study was developed to examine if inorganic fertilizer application over the residual fertility of broiler litter would reduce surplus soil nutrients i...

Corn stover harvest and tillage impacts on near-surface soil physical quality

USDA-ARS?s Scientific Manuscript database

Excessive harvest of corn (Zea mays L.) stover for ethanol production has raised concerns regarding negative consequences on soil physical quality. Our objective was to quantify the impact of two tillage practices and three levels of corn stover harvest on near-surface soil physical quality through ...

Closed-system freezing of soils in linings and earth embankment dams

NASA Astrophysics Data System (ADS)

Jones, C. W.

1981-03-01

A brief review of studies of closed-system freezing (no source of water except that in voids) of compacted soil canal linings, laboratory and field test results show that under certain soil and temperature conditions, freezing decreases soil density near the surface, but increases density at depth. In two linings, the average density increased slightly during a 20-year period. Frost penetration measurements made during the 1978-79 winter on a 1,5-thick reservoir lining, on three earth dams under construction, and on the Teton Dam remnant are shown along with associated soil conditions, air freezing indexes, and insulating effects of snow and, for one dam, a loose soil cover.

Compaction of AWBA fuel pellets without binders (AWBA Development Program)

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

Johnson, R.G.R.

1982-08-01

Highly active oxide fuel powders, composed of UO/sub 2/, UO/sub 2/-ThO/sub 2/, or ThO/sub 2/, were compacted into ultra-high density pellets without the use of binders. The objective of the study was to select the optimum die lubricant for compacting these powders into pellets in preparation for sintering to densities in excess of 97% Theoretical Density. The results showed that sintered density was a function of both the lubricant bulk density and concentration with the lowest bulk density lubricant giving the highest sintered densities with a lubricant concentration of 0.1 weight percent. Five calcium and zinc stearates were evaluated withmore » a calcium stearate with a 15 lb/ft/sup 3/ bulk density being the best lubricant.« less

The role of arbuscular mycorrhiza on change of heavy metal speciation in rhizosphere of maize in wastewater irrigated agriculture soil.

PubMed

Huang, Yi; Tao, Shu; Chen, You-jian

2005-01-01

To understand the roles of mycorrhiza in metal speciation in the rhizosphere and the impact on increasing host plant tolerance against excessive heavy metals in soil, maize (Zea mays L.) inoculated with arbuscular mycorrhizal fungus (Glomus mosseae) was cultivated in heavy metal contaminated soil. Speciations of copper, zinc and lead in the soil were analyzed with the technique of sequential extraction. The results showed that, in comparison to the bolked soil, the exchangeable copper increased from 26% to 43% in non-infected and AM-infected rhizoshpere respectively; while other speciation (organic, carbonate and Fe-Mn oxide copper) remained constant and the organic bound zinc and lead also increased but the exchangeable zinc and lead were undetectable. The organic bound copper, zinc and lead were higher by 15%, 40% and 20%, respectively, in the rhizosphere of arbuscular mycorrhiza infected maize in comparison to the non-infected maize. The results might indicate that mycorrhiza could protect its host plants from the phytotoxicity of excessive copper, zinc and lead by changing the speciation from bio-available to the non-bio-available form. The fact that copper and zinc accumulation in the roots and shoots of mycorrhia infected plants were significantly lower than those in the non-infected plants might also suggest that mycorrhiza efficiently restricted excessive copper and zinc absorptions into the host plants. Compared to the non-infected seedlings, the lead content of infected seedlings was 60% higher in shoots. This might illustrate that mycorrhiza have a different mechanism for protecting its host from excessive lead phytotoxicity by chelating lead in the shoots.

An application to model traffic intensity of agricultural machinery at field scale

NASA Astrophysics Data System (ADS)

Augustin, Katja; Kuhwald, Michael; Duttmann, Rainer

2017-04-01

Several soil-pressure-models deal with the impact of agricultural machines on soils. In many cases, these models were used for single spots and consider a static machine configuration. Therefore, a statement about the spatial distribution of soil compaction risk for entire working processes is limited. The aim of the study is the development of an application for the spatial modelling of traffic lanes from agricultural vehicles including wheel load, ground pressure and wheel passages at the field scale. The application is based on Open Source software, application and data formats, using python programming language. Minimum input parameters are GPS-positions, vehicles and tires (producer and model) and the tire inflation pressure. Five working processes were distinguished: soil tillage, manuring, plant protection, sowing and harvest. Currently, two different models (Diserens 2009, Rücknagel et al. 2015) were implemented to calculate the soil pressure. The application was tested at a study site in Lower Saxony, Germany. Since 2015, field traffic were recorded by RTK-GPS and used machine set ups were noted. Using these input information the traffic lanes, wheel load and soil pressure were calculated for all working processes. For instance, the maize harvest in 2016 with a crop chopper and one transport vehicle crossed about 55 % of the total field area. At some places the machines rolled over up to 46 times. Approximately 35 % of the total area was affected by wheel loads over 7 tons and soil pressures between 163 and 193 kPa. With the information about the spatial distribution of wheel passages, wheel load and soil pressure it is possible to identify hot spots of intensive field traffic. Additionally, the use of the application enables the analysis of soil compaction risk induced by agricultural machines for long- and short-term periods.

[Relation between species distribution of plant community and soil factors under grazing in alpine meadow].

PubMed

Niu, Yu Jie; Yang, Si Wei; Wang, Gui Zhen; Liu, Li; Du, Guo Zhen; Hua, Li Min

2017-12-01

The research selected the alpine meadow located in the northeastern margin of the Qinghai-Tibet Plateau to study the changes of vegetation community and soil properties under different grazing intensities, as well as the quantitative relation between the distribution patterns of plant species and the physical and chemical properties of soil. The results showed that the grazing caused the differentiation of the initial vegetation community with the dominant plants, Elymus nutans and Stipa grandis. In the plots with high and low grazing intensities, the dominant plants had changed to Kobresia humilis and Melissitus ruthenica, and E. nutans and Poa crymophila, respectively. With the increase of grazing intensity, the plant richness, importance value and biomass were significantly decreased. The sequence of plant species importance value in each plot against grazing intensity could be fitted by a logarithmic model. The number of required plant species was reduced while the importance value of the remaining plant species accounted for 50% of the importance value in the whole vegetation community. The available P, available K, soil compaction, soil water content, stable infiltration rate and large aggregate index were significantly changed with grazing intensity, however, the changes were different. The CCA ordination showed that the soil compaction was the key factor affecting the distribution pattern of the plant species under grazing. The variance decomposition indicated that the soil factors together explained 30.5% of the distribution of the plant species, in particular the soil physical properties alone explained 22.8% of the distribution of the plant species, which had the highest rate of contribution to the plant species distribution. The soil physical properties affected the distribution pattern of plant species on grazed alpine meadow.

Prediction of the wetting-induced collapse behaviour using the soil-water characteristic curve

NASA Astrophysics Data System (ADS)

Xie, Wan-Li; Li, Ping; Vanapalli, Sai K.; Wang, Jia-Ding

2018-01-01

Collapsible soils go through three distinct phases in response to matric suction decrease during wetting: pre-collapse phase, collapse phase and post-collapse phase. It is reasonable and conservative to consider a strain path that includes a pre-collapse phase in which constant volume is maintained and a collapse phase that extends to the final matric suction to be experienced by collapsible soils during wetting. Upon this assumption, a method is proposed for predicting the collapse behaviour due to wetting. To use the proposed method, two parameters, critical suction and collapse rate, are required. The former is the suction value below which significant collapse deformations take place in response to matric suction decease, and the later is the rate at which void ratio reduces with matric suction in the collapse phase. The value of critical suction can be estimated from the water-entry value taking account of both the microstructure characteristics and collapse mechanism of fine-grained collapsible soils; the wetting soil-water characteristic curve thus can be used as a tool. Five sets of data of wetting tests on both compacted and natural collapsible soils reported in the literature were used to validate the proposed method. The critical suction values were estimated from the water-entry value with parameter a that is suggested to vary between 0.10 and 0.25 for compacted soils and to be lower for natural collapsible soils. The results of a field permeation test in collapsible loess soils were also used to validate the proposed method. The relatively good agreement between the measured and estimated collapse deformations suggests that the proposed method can provide reasonable prediction of the collapse behaviour due to wetting.

Interaction between sulfur and lead in toxicity, iron plaque formation and lead accumulation in rice plant.

PubMed

Yang, Junxing; Liu, Zhiyan; Wan, Xiaoming; Zheng, Guodi; Yang, Jun; Zhang, Hanzhi; Guo, Lin; Wang, Xuedong; Zhou, Xiaoyong; Guo, Qingjun; Xu, Ruixiang; Zhou, Guangdong; Peters, Marc; Zhu, Guangxu; Wei, Rongfei; Tian, Liyan; Han, Xiaokun

2016-06-01

Human activities have resulted in lead and sulfur accumulation in paddy soils in parts of southern China. A combined soil-sand pot experiment was conducted to investigate the influence of S supply on iron plaque formation and Pb accumulation in rice (Oryza sativa L.) under two Pb levels (0 and 600 mg kg(-1)), combined with four S concentrations (0, 30, 60, and 120 mg kg(-1)). Results showed that S supply significantly decreased Pb accumulation in straw and grains of rice. This result may be attributed to the enhancement of Fe plaque formation, decrease of Pb availability in soil, and increase of reduced glutathione (GSH) in rice leaves. Moderate S supply (30 mg kg(-1)) significantly increased Fe plaque formation on the root surface and in the rhizosphere, whereas excessive S supply (60 and 120 mg kg(-1)) significantly decreased the amounts of iron plaque on the root surface. Sulfur supply significantly enhanced the GSH contents in leaves of rice plants under Pb treatment. With excessive S application, the rice root acted as a more effective barrier to Pb accumulation compared with iron plaque. Excessive S supply may result in a higher monosulfide toxicity and decreased iron plaque formation on the root surface during flooded conditions. However, excessive S supply could effectively decrease Pb availability in soils and reduce Pb accumulation in rice plants. Copyright © 2016 Elsevier Inc. All rights reserved.

Mars Rover Studies Soil on Mars

NASA Technical Reports Server (NTRS)

2004-01-01

Both out on the plains of Gusev Crater and in the 'Columbia Hills,' NASA's Mars Exploration Rover Spirit has encountered a thin (approximately 1 millimeter or 0.04 inch thick), light-colored, fine-grained layer of material on top of a dark-colored, coarser layer of soil. In the hills, Spirit stopped to take a closer look at soil compacted by one of the rover's wheels. Spirit took this image with the front hazard-avoidance camera during the rover's 314th martian day, or sol (Nov. 19, 2004).

Determination of specific gravity of municipal solid waste.

PubMed

Yesiller, Nazli; Hanson, James L; Cox, Jason T; Noce, Danielle E

2014-05-01

This investigation was conducted to evaluate experimental determination of specific gravity (Gs) of municipal solid waste (MSW). Water pycnometry, typically used for testing soils was adapted for testing MSW using a large flask with 2000 mL capacity and specimens with 100-350 g masses. Tests were conducted on manufactured waste samples prepared using US waste constituent components; fresh wastes obtained prior and subsequent to compaction at an MSW landfill; and wastes obtained from various depths at the same landfill. Factors that influence specific gravity were investigated including waste particle size, compaction, and combined decomposition and stress history. The measured average specific gravities were 1.377 and 1.530 for as-prepared/uncompacted and compacted manufactured wastes, respectively; 1.072 and 1.258 for uncompacted and compacted fresh wastes, respectively; and 2.201 for old wastes. The average organic content and degree of decomposition were 77.2% and 0%, respectively for fresh wastes and 22.8% and 88.3%, respectively for old wastes. The Gs increased with decreasing particle size, compaction, and increasing waste age. For fresh wastes, reductions in particle size and compaction caused occluded intraparticle pores to be exposed and waste particles to be deformed resulting in increases in specific gravity. For old wastes, the high Gs resulted from loss of biodegradable components that have low Gs as well as potential access to previously occluded pores and deformation of particles due to both degradation processes and applied mechanical stresses. The Gs was correlated to the degree of decomposition with a linear relationship. Unlike soils, the Gs for MSW was not unique, but varied in a landfill environment due both to physical/mechanical processes and biochemical processes. Specific gravity testing is recommended to be conducted not only using representative waste composition, but also using representative compaction, stress, and degradation states. Copyright © 2014 Elsevier Ltd. All rights reserved.

Validity and extension of the SCS-CN method for computing infiltration and rainfall-excess rates

NASA Astrophysics Data System (ADS)

Mishra, Surendra Kumar; Singh, Vijay P.

2004-12-01

A criterion is developed for determining the validity of the Soil Conservation Service curve number (SCS-CN) method. According to this criterion, the existing SCS-CN method is found to be applicable when the potential maximum retention, S, is less than or equal to twice the total rainfall amount. The criterion is tested using published data of two watersheds. Separating the steady infiltration from capillary infiltration, the method is extended for predicting infiltration and rainfall-excess rates. The extended SCS-CN method is tested using 55 sets of laboratory infiltration data on soils varying from Plainfield sand to Yolo light clay, and the computed and observed infiltration and rainfall-excess rates are found to be in good agreement.

55th Annual Fuze Conference

DTIC Science & Technology

2011-05-26

concrete plate and compact soil Confirmation: Complete Success both tests The TDD functioned as programmed; traces show entry and exit from each...concrete target and difference in deceleration levels between concrete and soil configuration The final exit & fire signals were generated as planned...Technical Data Package • Determine Process Capability • FMEA Manufacturing • Determine process capability • Cp = ( USL -LSL)/(6*Sigma) • Cpl

Harvesting Impacts on Soil Properties and Tree Regeneration in Pure and Mixed Aspen Stands

Treesearch

Melissa J. Arikian; Kiaus J. Peuttmann; Alaina L. Davis; George E. Host; John Zasada

1999-01-01

Impacts of clearcutting and selective harvesting on pure aspen/mixed aspen hardwood stands were examined in northern Minnesota. We studied these impacts on 18 stands, which were harvested 4 to 11 years ago and received no further treatment. In each stand, residual composition, soil compaction, and tree regeneration were determined along a gradient of disturbance in the...

Plant community responses to soil disturbance and herbicide treatments over 10 years on the Texas LTSP study

Treesearch

D. Andrew Scott; Richard H. Stagg

2013-01-01

Determining how anthropogenic disturbances affect site productivity through bioassays requires a complete understanding of both overstory and understory vegetation. This study was installed in 1997 to determine how soil compaction and intensive harvesting affected the inherent site productivity of pine stands on the western boundary of loblolly pine’s (Pinus...

Understory plant community response to compaction and harvest removal in a loblolly pine plantation

Treesearch

Benjamin J. Vierra; Gary B. Blank

2010-01-01

In 1992 the Southern Research Station, U.S. Forest Service, constructed three Long-Term Soil Productivity (LTSP) installations in a loblolly pine (Pinus taeda L.) plantation on the Croatan National Forest in Craven County, NC. The LTSP study consists of a nationwide network of experiment sites designed to examine the long-term effects of soil...

Reestablishing understory plants in overused wooded areas of Maryland state parks

Treesearch

Silas Little; John J. Mohr

1979-01-01

In four overused areas, the treatments of small plots were fencing, scarifying the soil, and mulching; fencing and mulching plus planting of shrubs, herbaceous plants, or greenbrier with shrubs or holly. After 3 years, soil compaction was two to four times as great in check plots as in treated plots. Understory cover varied with conditions, but because of volunteer...

Effects of subsoiling on woody roots of Jeffrey pines on two different soil types

Treesearch

W.J. Otrosina; Shi-Jean S. Sung

1995-01-01

This study was initiated to determine the long term effects of subsoiling to alleviate soil compaction due to use of mechanized harvesting equipment in forest stands. Two stands having a predominance of 90 to 110 year old Jeffrey pines (Pinus jeffreyi Grev. & Balf.) were selected for this investigation. Each stand was located on the Milford...

Evaluation of the effectiveness of riparian zone restoration in the southern Appalachians by assessing soil microbial populations

Treesearch

Guanglong Tian; James M. Vose; David C. Coleman; Christopher D. Geron; John T. Walker

2004-01-01

Microbial biomass, nitrifiers and denitrifiers in surface soil (0-10 cm) were quantified in a riparian zone restoration project at Coweeta, North Carolina, USA. Four treatments are included in this study: ( I ) a degraded (+N) riparian zone with continued compaction, vegetation removal, and nutrient addition (mow, roll, and nutrient addition);(2) a degraded (-N)...

[Evaluation on a demonstration project of ecological restoration of ditches at Qianwei Village of Chongming County, Shanghai].

PubMed

Zhou, Xiang-Xiang; Zhang, Li-Quan; Yuan, Lian-Qi

2008-02-01

By using biological slope-protection techniques, oxidation pond system, and zeolite treatment system, a demonstration project of ecological restoration of ditches at the Qianwei Village of Chongming County in Shanghai was implemented, and an evaluation on the project was made via a runoff simulation experiment and the measurements of the parameters soil shear strength, biodiversity, and ditch water quality. The results showed that covering the dich slopes with shrub could significantly increase soil shear strength, compactness and moisture content, and the formed vegetation had significant effects on retarding runoff and removing TSS (P < 0.05). Applying live fascines could significantly increase soil shear strength and TSS removal rate (P < 0.05), but its effects on increasing soil compactness and moisture content and retaining runoff were not significant. After the implement of the demonstration project, the total N and P concentrations in ditch water decreased significantly, habitat quality and aesthetic value of ditch slope improved, and biodiversity enhanced greatly. The integration of the biological techniques with other ecological restoration measures could stabilize ditch slope, improve ditch habitat quality, and restore the ecological environment of the ditches.

Preliminary Surficial Geology of the Dove Spring Off-Highway Vehicle Open Area, Mojave Desert, California

USGS Publications Warehouse

Miller, David M.; Amoroso, Lee

2007-01-01

Introduction As part of a U.S. Geological Survey (USGS) monitoring plan to evaluate the environmental impact of off-highway vehicle (OHV) use on Bureau of Land Management (BLM) land in California, this report presents results of geologic studies in the Dove Spring OHV Open Area. This study produced baseline data, which when combined with historic and current patterns of land use, forms the basis for vegetation and wildlife monitoring designed to address the following questions: 1. Is the density and length of OHV routes increasing? 2. Are there cumulative effects of past and current OHV use associated with changes in the environmental integrity of soils, plants, and wildlife? 3. Is the spread of invasive species associated with levels of OHV use? 4. Is there a threshold of OHV impact that might be translated to management action by the BLM? The monitoring studies will be used to collect baseline environmental information to determine levels of environmental impact of OHV use. This approach will use a low-impact area as a proxy for pre-impact conditions (substituting space for time) to determine thresholds of OHV impacts beyond which environmental integrity is affected. Indicators of environmental integrity will emphasize factors that are fundamental to ecosystem structure and function and likely to be sensitive to OHV impacts. Surficial geology is studied because material properties such as texture and chemistry strongly control soil moisture and nutrient availability and therefore affect plant growth and distribution. An understanding of surficial geology can be used to predict and extrapolate soil properties and improve understanding of vegetation assemblages and their distribution. In the present study, vegetation associations may be examined as a function of surficial geology as well as other environmental variables such as slope, aspect, NRCS (National Resources Conservation Service) soil classification, elevation, and land-use history. Ground measurements of vegetation, biological soil crusts, compaction, and other information may be correlated with land use to identify possible ecological thresholds in OHV use that require monitoring. Surficial geology is relevant for several other studies of OHV impact, such as soil compaction, dust emissions, and acceleration of erosion. Compaction, reduced infiltration, and accelerated erosion have been documented in Dove Spring Canyon because of OHV use (Snyder and others, 1976) and elsewhere in the Mojave Desert (e.g., Webb, 1983; Langdon, 2000). A surficial geologic map enables the use of geomorphic process models, which when combined with measured soil properties, such as texture, nutrient chemistry, and bulk density, allows spatial extrapolation of the properties. Maps can be produced that predict compaction susceptibility, moisture conditions, dust emissions, flood hazards, and erodibility, among other applications.

Assessment of microbial biomass carbon and nitrogen of native and non-native perennial pasture soils using hyperspectral data

USDA-ARS?s Scientific Manuscript database

Soil microbial biomass carbon (MBC) and nitrogen (MBN) are integral parts to soil organic matter. Increased production costs and chemical runoff can result from excessive application of fertilizer if these measurements are not used in total nutrient calculations. More timely and cost-effective me...

Development of disease-resistant walnut rootstocks: Integration of conventional and genomic approaches

USDA-ARS?s Scientific Manuscript database

English walnut (Juglans regia) is not typically grown on its own roots in commercial orchards due to its high susceptibility to key soil borne pathogens. Also, it is sensitive to excessive soil moisture and salinity, which are common abiotic stresses in CA soils. Northern CA black walnut (J. hindsi...

Development a fluvial detachment rate model to predict the erodibility of cohesive soils under the influence of seepage

USDA-ARS?s Scientific Manuscript database

Seepage influences the erodibility of streambanks, streambeds, dams, and embankments. Usually the erosion rate of cohesive soils due to fluvial forces is computed using an excess shear stress model, dependent on two major soil parameters: the critical shear stress (tc) and the erodibility coefficie...

Event-based estimation of water budget components using the network of multi-sensor capacitance probes

USDA-ARS?s Scientific Manuscript database

A time-scale-free approach was developed for estimation of water fluxes at boundaries of monitoring soil profile using water content time series. The approach uses the soil water budget to compute soil water budget components, i.e. surface-water excess (Sw), infiltration less evapotranspiration (I-E...

Responses of Earthworm to Aluminum Toxicity in Latosol

Treesearch

Jia-En Zhang; Jiayu Yu; Ying Ouyang; Huaqin Xu

2012-01-01

Excess aluminum (Al) in soils due to acid rain leaching is toxic to water resources and harmful to soil organisms and plants. This study investigated adverse impacts of Al levels upon earthworms (Eisenia fetida) from the latosol (acidic red soil). Laboratory experiments were performed to examine the survival and avoidance of earthworms from high Al...

Radioactivites in returned lunar materials and in meteorites

NASA Technical Reports Server (NTRS)

Fireman, E. L.

1983-01-01

The cosmic-ray, solar-flare, and solar-wind bombardments of lunar rocks and soils and meteorites were studied by measurements of tritium, carbon-14 and argon radioactivity. The radioactivity integrates the bombardment for a time period equal to several half-lines. H-3, Ar-37, Ar-39, C-14. For the interior samples of lunar rocks and for deep lunar soil samples, the amounts of the radioactivities were equal to those calculated for galactic cosmic-ray interactions. The top near-surface samples of lunar rocks and the shallow lunar soil samples show excess amounts of the radioactivities attributable to solar flares. Lunar soil fines contain a large amount of hydrogen due to implanted solar wind. Studies of the H-3 in lunar soils and in recovered Surveyor-3 materials gave an upper limit for the H-3/H ratio in the solar wind of 10 to the -11th power. Solar wind carbon is also implanted on lunar soil fines. Lunar soils collected on the surface contained a 0.14 component attributable to implanted solar wind C-14. The C-14/H ratio attributed to the solar wind from this C-14 excess is approximately 4 x 10 to the -11th power.

30 CFR 816.74 - Disposal of excess spoil: Preexisting benches.

Code of Federal Regulations, 2010 CFR

2010-07-01

... be backfilled and graded to— (1) Achieve the most moderate slope possible which does not exceed the... underdrains as necessary to control erosion, prevent water infiltration into the fill, and ensure stability..., concurrently compacted as necessary to ensure mass stability and to prevent mass movement, and graded to allow...

30 CFR 817.74 - Disposal of excess spoil: Preexisting benches.

Code of Federal Regulations, 2010 CFR

2010-07-01

... be backfilled and graded to— (1) Achieve the most moderate slope possible which does not exceed the... underdrains as necessary to control erosion, prevent water infiltration into the fill, and ensure stability..., concurrently compacted as necessary to ensure mass stability and to prevent mass movement, and graded to allow...

Experimental shock metamorphism of lunar soil

NASA Technical Reports Server (NTRS)

Schaal, R. B.; Horz, F.

1980-01-01

Shock experiments in the pressure range 15-73 GPa were performed on lunar soil 15101 in order to investigate the effect of a single impact event on the formation of soil breccias and agglutinates. The study has demonstrated that the propagation of a shock wave emanating from a single impact in porous particulate samples causes collision and shear of grains, collapse of pore spaces, and compaction which is sufficient to indurate soil at low pressures (15-18 GPa) without significant melting (less than 5%). These low pressures create soil breccias or weakly shocked soil fragments from loose regolith. At pressures above 65 GPa, shock melting produces a pumiceous whole-soil glass which is equivalent to agglutinate glass, glass fragments, or ropy glasses depending on the abundance of lithic fragments and relict grains.

Effects of nitrogen fertilization on the acidity and salinity of greenhouse soils.

PubMed

Han, Jiangpei; Shi, Jiachun; Zeng, Lingzao; Xu, Jianming; Wu, Laosheng

2015-02-01

A greenhouse pot experiment was conducted to study the effects of conventional nitrogen fertilization on soil acidity and salinity. Three N rates (urea; N0, 0 kg N ha(-1); N1, 600 kg N ha(-1); and N2, 1,200 kg N ha(-1)) were applied in five soils with different greenhouse cultivation years to evaluate soil acidification and salinization rate induced by nitrogen fertilizer in lettuce production. Both soil acidity and salinity increased significantly as N input increased after one season, with pH decrease ranging from 0.45 to 1.06 units and electrolytic conductivity increase from 0.24 to 0.68 mS cm(-1). An estimated 0.92 mol H(+) was produced for 1 mol (NO2 (-) + NO3 (-))-N accumulation in soil. The proton loading from nitrification was 14.3-27.3 and 12.1-58.2 kmol H(+) ha(-1) in the center of Shandong Province under N1 and N2 rate, respectively. However, the proton loading from the uptake of excess bases by lettuces was only 0.3-4.5 % of that from nitrification. Moreover, the release of protons induced the direct release of base cations and accelerated soil salinization. The increase of soil acidity and salinity was attributed to the nitrification of excess N fertilizer. Compared to the proton loading by lettuce, nitrification contributed more to soil acidification in greenhouse soils.

[Soil water reservoir properties and influencing factors of typical newly-established green belts of Shanghai Chenshan Botanical Garden, China.

PubMed

Wu, Hai Bing; Fang, Hai Lan; Peng, Hong Ling

2016-05-01

The effects of different vegetation types, compaction ways and soil basic physico-chemical properties on soil water reservoir in the typical newly-established green belts of Shanghai Chenshan Botanical Garden were studied. The results showed that the total reservoir capacity, detention capacity and effective storage for the Botanical Garden were lower than those of natural forests. However, the dead storage was very high accounting for 60.6% of the total reservoir capacity, resulting in reduced flood storage and drainage capacity for the greens. The total reservoir capacity and detention capacity of different vegetation types were in order of brush land> tree land> grassland> bamboo land> bare land. The effective storages of the brush land and the tree land were relatively high, whereas those of the bare land and the bamboo land were lower. The ratios of the dead storage over the total re-servoir capacity in the bare land and the bamboo land were relatively high with the values 65.5% and 67.6%, respectively. The total reservoir capacity, detention capacity and effective storage of the brush land were significantly different from those of the bare land. The vegetation significantly improved the water storage and retention capacity for the soil, while the compaction by large machinery and man-caused trampling reduced the total reservoir capacity, detention capacity and effective storage of soils. The water reservoir properties were influenced by soil bulk density, saturated hydraulic conductivity, capillary porosity, non-capillary porosity, total porosity, clay and organic matter contents. Therefore, improving the soil physico-chemical properties might increase the soil reservoir capacity of the urban green belt effectively.

Excessive application of pig manure increases the risk of P loss in calcic cinnamon soil in China.

PubMed

Yang, Yanju; Zhang, Haipeng; Qian, Xiaoqing; Duan, Jiannan; Wang, Gailan

2017-12-31

Soil phosphorus (P) is a critical factor affecting crop yields and water environmental quality. To investigate the degree of loss risk and forms of soil P in calcic cinnamon soil, the P fraction activities in soils were analysed using chemical methods, combined with an in situ field experiment. Seven treatments were set in this study, including control (unfertilized), no P fertilizer (No-P), mineral P fertilizer (Min-P), low (L-Man) and high (H-Man) quantities of pig manure, Min-P+L-Man, and Min-P+H-Man. The results showed that manure fertilizer could not only significantly increase maize yield but could also enhance the accumulation of soil P in organic and inorganic forms. After 23years of repeated fertilization, the soil Olsen-P contents respectively showed 64.7-, 43.7- and 31.9-fold increases in the Min-P+H-Man, Min-P+L-Man and H-Man treatments, while the soil Olsen-P in Min-P treatment only increased 23.7-fold. The soil Olsen-P thresholds ranged from 22.59 to 32.48mgkg -1 in calcic cinnamon soil to maintain a higher maize yield as well as a lower risk of P loss. Therefore, long-term excessive manure application could obviously raise the content of soil Olsen-P and increase the risk of P loss in calcic cinnamon soil. Copyright © 2017 Elsevier B.V. All rights reserved.

Effect of thinning and soil treatments on Pinus ponderosa plantations: 15-year results

Treesearch

Jianwei Zhang; Jeff Webster; David H. Young; Gary O. Fiddler

2016-01-01

Thinning with removal of whole trees in a plantation or natural forest stand raises two main concerns – soil compaction from the ground-based machinery and nutrient depletion particularly with whole tree harvest as is often practiced for attendant fuels reduction. To address these concerns, two sets of experimental treatments were imposed in young ponderosa pine...

Effects of timber harvesting on the lag time of a Caspar Creek watershed...a study in progress

Treesearch

Karen D. Hardison

1982-01-01

Researchers are not agreed on the effects of logging on lag time. Numerous studies have shown that the use of heavy equipment in logging operations can cause soil compaction. Also, associated roads alter natural drainage patterns by concentrating runoff and interrupting subsurface flow. As a result these researchers say, less infiltration into the soil takes place...

Assessment of the methane oxidation capacity of compacted soils intended for use as landfill cover materials

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

Rachor, Ingke, E-mail: i.rachor@ifb.uni-hamburg.de; Gebert, Julia; Groengroeft, Alexander

2011-05-15

The microbial oxidation of methane in engineered cover soils is considered a potent option for the mitigation of emissions from old landfills or sites containing wastes of low methane generation rates. A laboratory column study was conducted in order to derive design criteria that enable construction of an effective methane oxidising cover from the range of soils that are available to the landfill operator. Therefore, the methane oxidation capacity of different soils was assessed under simulated landfill conditions. Five sandy potential landfill top cover materials with varying contents of silt and clay were investigated with respect to methane oxidation andmore » corresponding soil gas composition over a period of four months. The soils were compacted to 95% of their specific proctor density, resulting in bulk densities of 1.4-1.7 g cm{sup -3}, reflecting considerably unfavourable conditions for methane oxidation due to reduced air-filled porosity. The soil water content was adjusted to field capacity, resulting in water contents ranging from 16.2 to 48.5 vol.%. The investigated inlet fluxes ranged from 25 to about 100 g CH{sub 4} m{sup -2} d{sup -1}, covering the methane load proposed to allow for complete oxidation in landfill covers under Western European climate conditions and hence being suggested as a criterion for release from aftercare. The vertical distribution of gas concentrations, methane flux balances as well as stable carbon isotope studies allowed for clear process identifications. Higher inlet fluxes led to a reduction of the aerated zone, an increase in the absolute methane oxidation rate and a decline of the relative proportion of oxidized methane. For each material, a specific maximum oxidation rate was determined, which varied between 20 and 95 g CH{sub 4} m{sup -2} d{sup -1} and which was positively correlated to the air-filled porosity of the soil. Methane oxidation efficiencies and gas profile data imply a strong link between oxidation capacity and diffusive ingress of atmospheric air. For one material with elevated levels of fine particles and high organic matter content, methane production impeded the quantification of methane oxidation potentials. Regarding the design of landfill cover layers it was concluded that the magnitude of the expected methane load, the texture and expected compaction of the cover material are key variables that need to be known. Based on these, a column study can serve as an appropriate testing system to determine the methane oxidation capacity of a soil intended as landfill cover material.« less

The triple oxygen isotope composition of phytoliths as a proxy of continental atmospheric humidity: insights from climate chamber and climate transect calibrations

NASA Astrophysics Data System (ADS)

Alexandre, Anne; Landais, Amarelle; Vallet-Coulomb, Christine; Piel, Clément; Devidal, Sébastien; Pauchet, Sandrine; Sonzogni, Corinne; Couapel, Martine; Pasturel, Marine; Cornuault, Pauline; Xin, Jingming; Mazur, Jean-Charles; Prié, Frédéric; Bentaleb, Ilhem; Webb, Elizabeth; Chalié, Françoise; Roy, Jacques

2018-05-01

Continental atmospheric relative humidity (RH) is a key climate parameter. Combined with atmospheric temperature, it allows us to estimate the concentration of atmospheric water vapor, which is one of the main components of the global water cycle and the most important gas contributing to the natural greenhouse effect. However, there is a lack of proxies suitable for reconstructing, in a quantitative way, past changes of continental atmospheric humidity. This reduces the possibility of making model-data comparisons necessary for the implementation of climate models. Over the past 10 years, analytical developments have enabled a few laboratories to reach sufficient precision for measuring the triple oxygen isotopes, expressed by the 17O-excess (17O-excess = ln (δ17O + 1) - 0.528 × ln (δ18O + 1)), in water, water vapor and minerals. The 17O-excess represents an alternative to deuterium-excess for investigating relative humidity conditions that prevail during water evaporation. Phytoliths are micrometric amorphous silica particles that form continuously in living plants. Phytolith morphological assemblages from soils and sediments are commonly used as past vegetation and hydrous stress indicators. In the present study, we examine whether changes in atmospheric RH imprint the 17O-excess of phytoliths in a measurable way and whether this imprint offers a potential for reconstructing past RH. For that purpose, we first monitored the 17O-excess evolution of soil water, grass leaf water and grass phytoliths in response to changes in RH (from 40 to 100 %) in a growth chamber experiment where transpiration reached a steady state. Decreasing RH from 80 to 40 % decreases the 17O-excess of phytoliths by 4.1 per meg/% as a result of kinetic fractionation of the leaf water subject to evaporation. In order to model with accuracy the triple oxygen isotope fractionation in play in plant water and in phytoliths we recommend direct and continuous measurements of the triple isotope composition of water vapor. Then, we measured the 17O-excess of 57 phytolith assemblages collected from top soils along a RH and vegetation transect in inter-tropical West and Central Africa. Although scattered, the 17O-excess of phytoliths decreases with RH by 3.4 per meg/%. The similarity of the trends observed in the growth chamber and nature supports that RH is an important control of 17O-excess of phytoliths in the natural environment. However, other parameters such as changes in the triple isotope composition of the soil water or phytolith origin in the plant may come into play. Assessment of these parameters through additional growth chambers experiments and field campaigns will bring us closer to an accurate proxy of changes in relative humidity.

Late-time X-ray signatures of compact binary mergers: potential counterparts of gravitational wave events

NASA Astrophysics Data System (ADS)

Tanvir, Nial

2017-09-01

Merging compact binaries (NS-NS or NS-BH) offer the best prospects for detection of EM signals accompanying gravitational wave (GW) events. They may be seen as bright short-GRBs (SGRBs), but this is likely to be rare due to beaming. Alternatively, more isotropic near-IR emission is predicted to result from the 'kilonova' produced by radioactive decay of neutron star ejecta. However, recent XMM observations have shown unexplained excess X-ray emission several days post-burst in two low-z SGRBs. This may indicate ongoing engine activity which both enhances the nIR emission, and crucially provides a potential new isotropic X-ray signature of compact binary mergers. We propose a detailed study of a further z<0.35 SGRB, to explore this phenomenon and inform future searches for GW counterparts.

Special Provisions for Intelligent Compaction of Stabilized Soil Subgrades

DOT National Transportation Integrated Search

2017-12-30

Slowing the deterioration of highway infrastructure, reducing carbon emissions, conserving resources, repurposing industrial waste-this Exploratory Advanced Research (EAR) Program project is pursuing multiple benefits through a unique experimental ap...

40 CFR 257.3-8 - Safety.

Code of Federal Regulations, 2012 CFR

2012-07-01

... application and compaction of soil or other suitable material over disposed solid waste at the end of each... disease vectors' access to the waste. (7) Putrescible wastes means solid waste which contains organic...

40 CFR 257.3-8 - Safety.

Code of Federal Regulations, 2014 CFR

2014-07-01

... application and compaction of soil or other suitable material over disposed solid waste at the end of each... disease vectors' access to the waste. (7) Putrescible wastes means solid waste which contains organic...

40 CFR 257.3-8 - Safety.

Code of Federal Regulations, 2010 CFR

2010-07-01

... application and compaction of soil or other suitable material over disposed solid waste at the end of each... disease vectors' access to the waste. (7) Putrescible wastes means solid waste which contains organic...

40 CFR 257.3-8 - Safety.

Code of Federal Regulations, 2011 CFR

2011-07-01

... application and compaction of soil or other suitable material over disposed solid waste at the end of each... disease vectors' access to the waste. (7) Putrescible wastes means solid waste which contains organic...

40 CFR 257.3-8 - Safety.

Code of Federal Regulations, 2013 CFR

2013-07-01

... application and compaction of soil or other suitable material over disposed solid waste at the end of each... disease vectors' access to the waste. (7) Putrescible wastes means solid waste which contains organic...

Vibrational collapse of boroxol rings in compacted B2O3 glasses: a study of Raman scattering and low temperature specific heat

NASA Astrophysics Data System (ADS)

Carini, Giovanni, Jr.; Carini, Giuseppe; D’Angelo, Giovanna; Federico, Mauro; Romano, Valentino

2018-05-01

Low and high frequency Raman scattering of B2O3 glasses, compacted under GPa pressures, has been performed to investigate structural changes due to increasing atomic packing. Compacted glasses, annealed at ambient temperature and pressure, experience a time-dependent decrease of the density to a smaller constant value over a period of few months, displaying a permanent plastic deformation. Increasing densification determines a parallel and progressive decrease of the intensity of the Boson peak and the main band at 808 cm‑1, both these modes arising from localized vibrations involving planar boroxol rings (B3O6), the glassy units formed from three basic BO3 triangles. The 808 cm‑1 mode preserves its frequency, while the BP evidences a well-defined frequency increase. The high-frequency multicomponent band between 1200 and 1600 cm‑1 also changes with increasing densification, disclosing a decreasing intensity of the 1260 cm‑1 mode due to oxygen vibrations of BO3 units bridging boroxol rings. This indicates the gradual vibrational collapse of groups formed from rings connected by more complex links than a single bridging oxygen. The observed behaviours suggest that glass compaction causes severe deformation of boroxol rings, determining a decrease of groups which preserve unaltered their vibrational activity. Growing glass densification stiffens the network and leads to a decrease of the excess heat capacity over the Debye prediction below 20 K, which is not accounted for by the hardening of the elastic continuum. By using the low-frequency Raman scattering to determine the temperature dependence of the heat capacity, it has been evaluated the density of low-frequency vibrational states which discloses a significant reduction of excess modes with increasing density.

Design phase identification of high pile rebound soils : final report

DOT National Transportation Integrated Search

2010-12-15

An engineering problem has occurred when installing displacement piles in certain soils. During driving, piles are rebounding excessively during each hammer blow, causing delay and as a result may not achieve the required design capacities. Piles dri...

Highly charged swelling mica reduces free and extractable Cu levels in Cu-contaminated soils.

PubMed

Stuckey, Jason W; Neaman, Alexander; Ravella, Ramesh; Komarneni, Sridhar; Martínez, Carmen Enid

2008-12-15

Smelting of copper (Cu) results in the atmospheric deposition of Cu onto surrounding soils. Excess concentrations of Cu in soils can be absorbed by soil biota to toxic levels or leached into the groundwater, threatening the entire ecosystem. A means to restrict Cu mobility and uptake by plants is to remove it from the aqueous phase by applying an adsorptive material. A synthetic clay (highly charged swelling mica) was tested for its ability to decrease the levels of free and 0.1 M KNO3-extractable Cu in 15 surface soils from three different Cu mining areas in central Chile. The soils contained excessive total Cu levels (112-2790 mg Cu (kg soil)(-1)), while extractable Cu ranged from 0.3 to 22.9 mg Cu L(-1). The mica was applied to each soil at rates of 0.1%, 1%, and 2% (w/w). A 2% sodium-montmorillonite treatment and the nonamended soil served as controls. The order of treatment efficacy in reducing extractable Cu and free Cu2+ for low pH soils ( 1% mica > 2% montmorillonite > 0.1% mica. At 120 days, the 2% mica treatment maintained reductions of up to 93% in the free Cu2+ activity and up to 75% in the extractable Cu concentration upon acidification to the original soil pH value. In addition, Cu retention in mica-treated soils was more resistant to acidification than in lime-treated soils. This mica has promise for the remediation of acidic soils with metal contamination at the surface.

Soggy soils and sustainability: forested wetlands in southeast Alaska.

Treesearch

Sally Duncan

2002-01-01

The question has risen over whether forested wetlands in southeast Alaska are suitable for sustainable timber production. A significant factor limiting forest productivity in this region is excess soil moisture. Very little is known about the soil conditions that influence tree growth on forested wetlands. A research study was completed to provide information on the...

Hillslope erosion rates in the oak savannas of the southwestern borderlands region

Treesearch

Aaron T. Kauffman; Cody L. Stropki; Peter F. Ffolliott; Gerald J. Gottfried; Daniel G. Neary

2007-01-01

Hillslope soil erosion on watershed landscapes can lower the productivity of upland sites and adversely impact water quality and downstream (off-site) areas. It is not surprising, therefore, that excessive soil erosion and the consequent sedimentation can represent significant costs to the land and people that are affected. The first known estimates of hillslope soil...

Gypsum adherence to forage: consideration for excessive ingestion by ruminates

USDA-ARS?s Scientific Manuscript database

Gypsum (calcium sulfate dihydrate, CaSO4•2H2O) has long been used as a soil amendment to improve soil conditions and its use has recently been encouraged by the USDA-NRCS for soil conservation through a new National Conservation Practice Standard: Code 333. However, there is concern regarding the e...

Biochar can be used to recapture essential nutrients from dairy wastewater and improve soil quality

NASA Astrophysics Data System (ADS)

Ghezzehei, T. A.; Sarkhot, D. V.; Berhe, A. A.

2014-04-01

Recently, the potential for biochar use to recapture excess nutrients from dairy wastewater has been a focus of a growing number of studies. It is suggested that biochar produced from locally available waste biomass can be important in reducing release of excess nutrient elements from agricultural runoff, improving soil productivity, and long-term carbon (C) sequestration. Here we present a review of a new approach that is showing promise for the use of biochar for nutrient capture. Using batch sorption experiments, it has been shown that biochar can adsorb up to 20 to 43% of ammonium and 19-65% of the phosphate in flushed dairy manure in 24 h. These results suggest a potential of biochar for recovering essential nutrients from dairy wastewater and improving soil fertility if the enriched biochar is returned to soil. Based on the sorption capacity of 2.86 and 0.23 mg ammonium and phosphate, respectively, per gram of biochar and 10-50% utilization of available excess biomass, in the state of California (US) alone, 11 440 to 57 200 t of ammonium-N and 920-4600 t of phosphate can be captured from dairy waste each year while at the same time disposing up to 8-40 million tons of waste biomass.

Absorption of excess selenium and sulfur by plants and animals

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

Mayland, H.F.

1995-09-01

High concentrations of selenium (Se) and sulfur (S) often occur in over-burden soils and underlying shales associated with western coal mining areas. Knowing the role of Se and S in the soil-plant-animal system is important for proper management of mine spoil reclamation. This paper will discuss recent findings about Se and S forms in soils, their absorption and accumulation by plants, and their subsequent toxicity to grazing animals. Selenium absorbed by the accumulating plants is generally metabolized to non-protein forms, while that absorbed by the non-accumulating plants occurs predominantly as selenomethionine. Selenomethionine is readily absorbed by animals. In animals, bothmore » acute and chronic forms of selenosis are known. Death occurs when a large dose of highly-available Se is ingested. One chronic form includes symptoms of inappetence, hair loss, hardening and extension of nails and hooves, reduced weight gains, and poor reproductive performance. Beath and Rosenfield identified {open_quotes}blind staggers{close_quotes} as another from of selenosis, but this disorder; more appropriately called polioencephalomalcia (PEM), occurred only in ruminants. However; the historical association of selenosis to blind staggers has been questioned. Recent experimental evidence has shown that PEM is likely caused by excess SO{sub 4}. Cases of this disorder have been documented in the USA and Canada when ruminants have high S intake from herbage and/or drinking water. Western mine reclamation decisions should consider the potential for not only excess Se, but also excess SO{sub 4} in water, soil, and plants.« less

Effects of fines content on hydraulic conductivity and morphology of laterite soil as hydraulic barrier

NASA Astrophysics Data System (ADS)

Bello Yamusa, Yamusa; Yunus, Nor Zurairahetty Mohd; Ahmad, Kamarudin; Rahman, Norhan Abd; Sa'ari, Radzuan

2018-03-01

Laterite soil was investigated to find out the effects of fines content and to identify the micro-structural and molecular characteristics to evaluate its potentiality as a compacted soil landfill liner material. Tests were carried out on natural soil and reconstituted soil by dry weight of soil samples to determine the physical and engineering properties of the soil. All tests were carried out on the samples by adopting the British Standard 1377:1990. The possible mechanisms that contributed to the clay mineralogy were analyzed using spectroscopic and microscopic techniques such as field emission scanning electron microscopy (FESEM), energy-dispersive X-ray (EDX) and X-ray diffractometry (XRD). The laterite soil was found to contain kaolinite as the major clay minerals. A minimum of 50% fines content of laterite soil met the required result for hydraulic barriers in waste containment facilities.

Green Infrastructure 101 - slides

EPA Science Inventory

Background & problem statement for urban stormwater Regulatory authority for point dischargesBrief history of stormwater controlsSix case studies: Effect of soil compaction on infiltration Accotink stream restoration Fairfax, Virginia New York City Staten Island Bluebelt projec...

Green Infrastructure 101 - Rutgers

EPA Science Inventory

Background & problem statement for urban stormwater Regulatory authority for point dischargesBrief history of stormwater controlsSix case studies: Effect of soil compaction on infiltration Accotink stream restoration Fairfax, Virginia New York City Staten Island Bluebelt projects...

Hurricane Katrina sediment slowed elevation loss in subsiding brackish marshes of the Mississippi River delta

USGS Publications Warehouse

McKee, K.L.; Cherry, J.A.

2009-01-01

Although hurricanes can damage or destroy coastal wetlands, they may play a beneficial role in reinvigorating marshes by delivering sediments that raise soil elevations and stimulate organic matter production. Hurricane Katrina altered elevation dynamics of two subsiding brackish marshes in the Mississippi River deltaic plain by adding 3 to 8 cm of sediment to the soil surface in August 2005. Soil elevations at both sites subsequently declined due to continued subsidence, but net elevation gain was still positive at both Pearl River (+1.7 cm) and Big Branch (+0.7 cm) marshes two years after the hurricane. At Big Branch where storm sediments had higher organic matter and water contents, post-storm elevation loss was more rapid due to initial compaction of the storm layer in combination with root-zone collapse. In contrast, elevation loss was slower at Pearl River where the storm deposit (high sand content) did not compact and the root zone did not collapse. Vegetation at both sites fully recovered within one year, and accumulation of root matter at Big Branch increased 10-fold from 2005 to 2006, suggesting that the hurricane stimulated belowground productivity. Results of this study imply that hurricane sediment may benefit subsiding marshes by slowing elevation loss. However, long-term effects of hurricane sediment on elevation dynamics will depend not only on the amount of sediment deposited, but on sediment texture and resistance to compaction as well as on changes in organic matter accumulation in the years following the hurricane.

Impacts of feral horses on a desert environment

PubMed Central

2009-01-01

Background Free-ranging horses (Equus caballus) in North America are considered to be feral animals since they are descendents of non-native domestic horses introduced to the continent. We conducted a study in a southern California desert to understand how feral horse movements and horse feces impacted this arid ecosystem. We evaluated five parameters susceptible to horse trampling: soil strength, vegetation cover, percent of nonnative vegetation, plant species diversity, and macroinvertebrate abundance. We also tested whether or not plant cover and species diversity were affected by the presence of horse feces. Results Horse trailing resulted in reduced vegetation cover, compacted soils, and in cases of intermediate intensity disturbance, increased plant species diversity. The presence of horse feces did not affect plant cover, but it did increase native plant diversity. Conclusion Adverse impacts, such as soil compaction and increased erosion potential, were limited to established horse trails. In contrast, increased native plant diversity near trails and feces could be viewed as positive outcomes. Extensive trailing can result in a surprisingly large impact area: we estimate that < 30 horses used > 25 km2 of trails in our study area. PMID:19903355

Impacts of feral horses on a desert environment.

PubMed

Ostermann-Kelm, Stacey D; Atwill, Edward A; Rubin, Esther S; Hendrickson, Larry E; Boyce, Walter M

2009-11-10

Free-ranging horses (Equus caballus) in North America are considered to be feral animals since they are descendents of non-native domestic horses introduced to the continent. We conducted a study in a southern California desert to understand how feral horse movements and horse feces impacted this arid ecosystem. We evaluated five parameters susceptible to horse trampling: soil strength, vegetation cover, percent of nonnative vegetation, plant species diversity, and macroinvertebrate abundance. We also tested whether or not plant cover and species diversity were affected by the presence of horse feces. Horse trailing resulted in reduced vegetation cover, compacted soils, and in cases of intermediate intensity disturbance, increased plant species diversity. The presence of horse feces did not affect plant cover, but it did increase native plant diversity. Adverse impacts, such as soil compaction and increased erosion potential, were limited to established horse trails. In contrast, increased native plant diversity near trails and feces could be viewed as positive outcomes. Extensive trailing can result in a surprisingly large impact area: we estimate that < 30 horses used > 25 km2 of trails in our study area.

FORAGES AND PASTURES SYMPOSIUM: Improving soil health and productivity on grasslands using managed grazing of livestock.

PubMed

Russell, J R; Bisinger, J J

2015-06-01

Beyond grazing, managed grasslands provide ecological services that may offer economic incentives for multifunctional use. Increasing biodiversity of plant communities may maximize net primary production by optimizing utilization of available light, water, and nutrient resources; enhance production stability in response to climatic stress; reduce invasion of exotic species; increase soil OM; reduce nutrient leaching or loading in surface runoff; and provide wildlife habitat. Strategically managed grazing may increase biodiversity of cool-season pastures by creating disturbance in plant communities through herbivory, treading, nutrient cycling, and plant seed dispersal. Soil OM will increase carbon and nutrient sequestration and water-holding capacity of soils and is greater in grazed pastures than nongrazed grasslands or land used for row crop or hay production. However, results of studies evaluating the effects of different grazing management systems on soil OM are limited and inconsistent. Although roots and organic residues of pasture forages create soil macropores that reduce soil compaction, grazing has increased soil bulk density or penetration resistance regardless of stocking rates or systems. But the effects of the duration of grazing and rest periods on soil compaction need further evaluation. Because vegetative cover dissipates the energy of falling raindrops and plant stems and tillers reduce the rate of surface water flow, managing grazing to maintain adequate vegetative cover will minimize the effects of treading on water infiltration in both upland and riparian locations. Through increased diversity of the plant community with alterations of habitat structure, grazing systems can be developed that enhance habitat for wildlife and insect pollinators. Although grazing management may enhance the ecological services provided by grasslands, environmental responses are controlled by variations in climate, soil, landscape position, and plant community resulting in considerable spatial and temporal variation in the responses. Furthermore, a single grazing management system may not maximize livestock productivity and each of the potential ecological services provided by grasslands. Therefore, production and ecological goals must be integrated to identify the optimal grazing management system.

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.

Use of reinforced soil foundation (RSF) to support shallow foundation : technical summary report, November 2008.

DOT National Transportation Integrated Search

2008-11-01

The presence of a weak soil supporting structural foundations results in low load bearing capacity and : excessive settlements, which can cause structural damage, reduction in durability, and/or deterioration in : performance level. Conventional trea...

Environmental Assessment: PL 84-99 Levee Rahabilitation Program Lower Platte South Natural Resource District Salt Creek, Lincoln, Lancaster County, Nebraska

DTIC Science & Technology

2015-03-01

lost bank material with compacted, non-dispersive clay and riprap; constructing landward piggy-back levees at discrete locations if space is available...consist of approximately seven miles of levees. The levees have 3:1 side slopes that are made up of clay soil, with a two-foot minimum freeboard. The...reshaping the levee and replacing lost bank material with compacted, non-dispersive clay and riprap or building a landside piggy back levee if space is

A radio spectral index map and catalogue at 147-1400 MHz covering 80 per cent of the sky

NASA Astrophysics Data System (ADS)

de Gasperin, F.; Intema, H. T.; Frail, D. A.

2018-03-01

The radio spectral index is a powerful probe for classifying cosmic radio sources and understanding the origin of the radio emission. Combining data at 147 MHz and 1.4 GHz from the TIFR GMRT Sky Survey (TGSS) and the NRAO VLA Sky Survey (NVSS), we produced a large-area radio spectral index map of ˜80 per cent of the sky (Dec. > - 40 deg), as well as a radio spectral index catalogue containing 1396 515 sources, of which 503 647 are not upper or lower limits. Almost every TGSS source has a detected counterpart, while this is true only for 36 per cent of NVSS sources. We released both the map and the catalogue to the astronomical community. The catalogue is analysed to discover systematic behaviours in the cosmic radio population. We find a differential spectral behaviour between faint and bright sources as well as between compact and extended sources. These trends are explained in terms of radio galaxy evolution. We also confirm earlier reports of an excess of steep-spectrum sources along the galactic plane. This corresponds to 86 compact and steep-spectrum source in excess compared to expectations. The properties of this excess are consistent with normal non-recycled pulsars, which may have been missed by pulsation searches due to larger than average scattering along the line of sight.

Airships for transporting highly volatile commodities

NASA Technical Reports Server (NTRS)

Sonstegaard, M.

1975-01-01

Large airships may prove feasible as carriers of commodities that move as gases or cryogenic liquids; buoyant gaseous cargo could be ballasted with liquid cargo. Airships are compact in shape, operate in a rarified medium, and hence can be fast and perhaps economic carriers of costly cryogenic tanks. The high-pressure gas pipeline has excessive surface area when carrying hydrogen and excessive fluid density when carrying natural gas, while the cryogenic ocean tanker runs in a dense medium and makes gravity waves. But the airship, despite its fluid dynamic advantages, faces problems of safety, weather, and altitude control.

Pinestraw raking, fertilization and poultry litter amendment effects on soil physical properties for a mid-rotation loblolly pine plantation

Treesearch

William B. Patterson; Michael A. Blazier; Steven L. Holtard

2010-01-01

Frequent pinestraw raking and removal in pine plantations has led to concerns about nutrient removal from the stand. While soil chemistry of raked stands has been studied, little attention has been placed on potential compaction from raking operations. Four treatments were applied to a 16-year-old loblolly pine plantation at the Louisiana State University AgCenter...

First-year survival and growth of three species assemblages planted on reclaimed mine land as affected by three levels of silvicultural intensity

Treesearch

Chad N. Casselman; Thomas R. Fox; James A. Burger

2006-01-01

Surface mined land in the Appalachian coal-producing region have been found to exhibit growing conditions that are unfavorable for the establishment of productive forests including dense ground covers, compacted soil materials, and unfavorable soil chemical properties. To address these concerns, a 3 x 3 x 3 factor random complete block experiment was used to...

Scale and Time Effects in Hydraulic Fracturing.

DTIC Science & Technology

1984-07-01

An experimental study was conducted to determine the effects of scale and time on hydraulic fracturing in compacted samples of Teton Dam silt and...occurrence of hydraulic fracturing . Finite element analyses were used to investigate the possible effects of nonlinear soil behavior. Both experimental and...theoretical studies show that hydraulic fracturing can be initiated by seepage-induced forces without the presence of a preexisting flaw in the soil. (Author)

The interaction of water vapor with a lunar soil, a compacted soil, and a cinder-like rock fragment

NASA Technical Reports Server (NTRS)

Cadenhead, D. A.; Stetter, J. R.

1974-01-01

A volumetric adsorption system incorporating a pressure gauge was employed to determine nitrogen adsorption and evaluate surface areas. The water adsorption of the lunar samples was measured with the aid of a gravimetric adsorption system including a microbalance. The results obtained in the investigation for the three samples are discussed in detail, giving attention to aspects of dehydroxylation and rehydroxylation.

How far can we prevent further physical soil degradation in the future?

NASA Astrophysics Data System (ADS)

Horn, Rainer

2017-04-01

Arable as well as forest soils are exposed to increasing external stresses, which coincide with a further and deeper reaching soil degradation, which may result in an aggravation of hydraulic, gaseous, thermal but also physicochemical and chemical soil functions. The decline coincides with a simultaneous reduction in useable land areas and worsens food production amongst others. Therefore, it is mandatory, that stable soil structure from the surface down to depth prevents soil compaction, sustains water infiltration, reduces rates of soil erosion by water and wind in each case to the minimum possible under the soil, terrain, land use, and climatic conditions in which the soils occur. It improves organic carbon storage in soils and optimizes microbial activity and functions. These benefits coincide with sustainable soil properties and soil management systems, which prevent - deep mechanical stress propagation which can cause irreversible soil deformation, - loss of surface soil layers with coinciding organic and mineral nutrient pool available for microbial processing and plant uptake, - Truncation of soil horizons, or damage on private and public infrastructures (roads, houses) and downstream fields. In order to prevent negative impacts on soils, it is recommended, that A) concerning prevention of soil compaction - stresses applied to soils shall not exceed the mechanical soil stability to maintain the actual functioning of chemical, physical and biological processes and to utilize their resilience (i.e. the elasticity), - land use management strategies have to be related to the actual soil properties in order to optimize plant growth, yield, filtering and buffering of infiltrating water, and carbon sequestration. B) soil erosion by - water, wind, and tillage is counteracted by an adequate surface soil stability including a site specific residue management (e.g. conservation tillage), controlled traffic and harvesting, ecological grassland use strategies (e.g. fodder production and harvesting, adequate animal grazing), - wind is furthermore minimized by adequate hedgerow plantations, continuous cover crop growth, optimized particle bindings by water, infiltrating organic acids, appropriate grazing intensity. Agroforestry can be considered as an additional positive measure to reduce soil erosion risks generally and to ameliorate degraded sites. C) -plant cover on slopes remains untouched, overgrazing and consecutive soil homogenization especially under moist climatic conditions must be prevented but adjusted to the actual structure stability of the hillsides. The communication of these findings followed by application of such measures can help farmers and foresters as well as landowners to prevent (further) physical soil degradation in the future.

Analysis of the Feasibility of Using Soil from the Municipality of Goytacazes/RJ for Production of Soil-Cement Brick

NASA Astrophysics Data System (ADS)

Alexandre, J.; Azevedo, A. R. G.; Theophilo, M. M. D.; Xavier, C. G.; Paes, A. L. C.; Monteiro, S. N.; Margem, F. M.; Azeredo, N. G.

The use of bricks of soil-cement is proving to be an important constructive methodology due to low environmental impact in the production process of these blocks comparing with conventional bricks are burnt, besides being easy to produce. However during the process of production of bricks, which are compressed, knowledge of the properties of the soil used is critical to the quality and durability of the blocks. The objective of this work is to evaluate the feasibility of using soil from the municipality of Goytacazes for the production of soil-cement bricks. Assays were performed the compaction, liquid limit, plastic limit, particle size analysis, EDX and X-Ray diffraction for later pressed blocks and analyze their compressive strength and water absorption.

Effects of land use pattern on soil water in revegetation watersheds in semi-arid Chinese Loess Plateau

NASA Astrophysics Data System (ADS)

Yang, Lei; Chen, Liding; Wei, Wei

2017-04-01

Soil water stored below rainfall infiltration depth is a reliable water resource for plant growth in arid and semi-arid regions. For decreasing serious soil erosion, large-scale human-introduced vegetation restoration was initiated in Chinese Loess Plateau in late 1990s. However, these activities may result in excessive water consumption and soil water deficit if no appropriate scientific guidance were offered. This in turn impacts the regional ecological restoration and sustainable management of water resources. In this study, soil water content data in depth of 0-5 m was obtained by long-term field observation and geostatistical method in 6 small watersheds covered with different land use pattern. Profile characteristics and spatial-temporal patterns of soil water were compared between different land use types, hillslopes, and watersheds. The results showed that: (1) Introduced vegetation consumed excessive amount of water when compared with native grassland and farmland, and induced temporally stable soil desiccation in depth of 0-5 m. The introduced vegetation decreased soil water content to levels lower than the reference value representing no human impact in all soil layers. (2) The analysis of differences in soil water at hillslope and watershed scales indicated that land use determined the spatial and temporal variability of soil water. Soil water at watershed scale increased with the increasing area of farmland, and decreased with increasing percentage of introduced vegetation. Land use structure determined the soil water condition and land use pattern determined the spatial-temporal variability of soil water at watershed scale. (3) Large-scale revegetation with introduced vegetation diminished the spatial heterogeneity of soil water at different scales. Land use pattern adjustment could be used to improve the water resources management and maintain the sustainability of vegetation restoration.

Educating for Ecological Sustainability: Montessori Education Leads the Way

ERIC Educational Resources Information Center

Sutton, Ann

2009-01-01

These days, the word "green," and the more comprehensive term "sustainability," surface in numerous arenas, whether it be exhortations to recycle more, employ compact fluorescent lightbulbs, use less hot water, avoid products with excess packaging, adjust thermostats, plant trees, turn off electronic devices when not in use, or buy organic and…

Effective depth of soil compaction : [brief].

DOT National Transportation Integrated Search

2015-05-01

The Wisconsin Department of Transportation (WisDOT) spends approximately 10 percent of : its improvement project budget on embankment construction each year. A critical aspect of : embankment construction is stability. It is needed to provide an acce...

Evaluation of vibration limits and mitigation techniques for urban construction : [summary].

DOT National Transportation Integrated Search

2013-10-01

Construction activities such as pile driving and : dynamic compaction of loose soils induce ground : and structure vibrations. Their effects may annoy : local populations, disturb sensitive equipment, or : reduce structures serviceability and dura...

43 CFR 4130.3-2 - Other terms and conditions.

Code of Federal Regulations, 2011 CFR

2011-10-01

..., or restoration of vigor of plants, provide for the improvement of riparian areas to achieve proper... of applicable land use plans, or to prevent compaction of wet soils, such as where delay of spring...

Robust and compact entanglement generation from diode-laser-pumped four-wave mixing

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

Lawrie, B. J.; Yang, Y.; Eaton, M.

Four-wave-mixing processes are now routinely used to demonstrate multi-spatial-mode Einstein- Podolsky-Rosen entanglement and intensity difference squeezing. Recently, diode-laser-pumped four-wave mixing processes have been shown to provide an affordable, compact, and stable source for intensity difference squeezing, but it was unknown if excess phase noise present in power amplifier pump configurations would be an impediment to achieving quadrature entanglement. Here, we demonstrate the operating regimes under which these systems are capable of producing entanglement and under which excess phase noise produced by the amplifier contaminates the output state. We show that Einstein-Podolsky-Rosen entanglement in two mode squeezed states can be generatedmore » by a four-wave-mixing source deriving both the pump field and the local oscillators from a tapered-amplifier diode-laser. In conclusion, this robust continuous variable entanglement source is highly scalable and amenable to miniaturization, making it a critical step toward the development of integrated quantum sensors and scalable quantum information processors, such as spatial comb cluster states.« less

Robust and compact entanglement generation from diode-laser-pumped four-wave mixing

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

Lawrie, B. J., E-mail: lawriebj@ornl.gov; Pooser, R. C.; Yang, Y.

Four-wave-mixing processes are now routinely used to demonstrate multi-spatial-mode Einstein-Podolsky-Rosen entanglement and intensity difference squeezing. Diode-laser-pumped four-wave mixing processes have recently been shown to provide an affordable, compact, and stable source for intensity difference squeezing, but it was unknown if excess phase noise present in power amplifier pump configurations would be an impediment to achieving quadrature entanglement. Here, we demonstrate the operating regimes under which these systems are capable of producing entanglement and under which excess phase noise produced by the amplifier contaminates the output state. We show that Einstein-Podolsky-Rosen entanglement in two mode squeezed states can be generated bymore » a four-wave-mixing source deriving both the pump field and the local oscillators from a tapered-amplifier diode-laser. This robust continuous variable entanglement source is highly scalable and amenable to miniaturization, making it a critical step toward the development of integrated quantum sensors and scalable quantum information processors, such as spatial comb cluster states.« less

Robust and compact entanglement generation from diode-laser-pumped four-wave mixing

DOE PAGES

Lawrie, B. J.; Yang, Y.; Eaton, M.; ...

2016-04-11

Four-wave-mixing processes are now routinely used to demonstrate multi-spatial-mode Einstein- Podolsky-Rosen entanglement and intensity difference squeezing. Recently, diode-laser-pumped four-wave mixing processes have been shown to provide an affordable, compact, and stable source for intensity difference squeezing, but it was unknown if excess phase noise present in power amplifier pump configurations would be an impediment to achieving quadrature entanglement. Here, we demonstrate the operating regimes under which these systems are capable of producing entanglement and under which excess phase noise produced by the amplifier contaminates the output state. We show that Einstein-Podolsky-Rosen entanglement in two mode squeezed states can be generatedmore » by a four-wave-mixing source deriving both the pump field and the local oscillators from a tapered-amplifier diode-laser. In conclusion, this robust continuous variable entanglement source is highly scalable and amenable to miniaturization, making it a critical step toward the development of integrated quantum sensors and scalable quantum information processors, such as spatial comb cluster states.« less

Macro and micro nutrient uptake parameters and use efficiency in cacao genotypes influenced by deficient to excess levels of soil K

USDA-ARS?s Scientific Manuscript database

Cacao (Theobroma cacao L.) is an important economic crop for many of the tropical countries. Adequate levels of soil K are essential for good growth and achieving high cocoa bean yields. Soils under cacao invariably have low levels of plant available K to support good cacao growth. Growth chamber ex...

Effects of harvesting on nitrogen and phosphorus availability in riparian management zone soils in Minnesota, USA

Treesearch

Douglas N. Kastendick; Eric K. Zenner; Brian J. Palik; Randall K. Kolka; Charles R. Blinn

2012-01-01

Riparian management zones (RMZs) protect streams from excess nutrients, yet few studies have looked at soil nutrients in forested RMZs or the impacts of partial harvesting on nutrient availability. We investigated the impacts of upland clearcutting in conjunction with uncut and partially harvested RMZs (40% basal area reduction) on soil nutrients in forests in...

Poroelastic theory of consolidation in unsaturated soils incorporating gravitational body forces

NASA Astrophysics Data System (ADS)

Lo, Wei-Cheng; Chao, Nan-Chieh; Chen, Chu-Hui; Lee, Jhe-Wei

2017-08-01

The generalization of the poroelasticity theory of consolidation in unsaturated soils to well represent gravitational body forces is presented in the current study. Three partial differential equations featuring the displacement vector of the solid phase, along with the excess pore water and air pressures as dependent variables are derived, with coupling that occurs in the first-order temporal- and spatial- derivative terms. The former arises from viscous drag between solid and fluid, whereas the latter is attributed to the presence of gravity. Given the physically-consistent initial and boundary conditions, these coupled equations are numerically solved under uniaxial strain as a representative example. Our results reveal that variations in the excess pore water pressure due to the existence of gravitational forces increase with soil depth, but these variations are not significant if the soil layer is not sufficiently long. A dimensionless parameter is defined theoretically to quantify the impact of those forces on the final total settlement. This impact is shown to become greater as the soil layer is less stiff and has more length, and bears an inversely-proportional trend with initial water saturation.

Developing Soil Models for Dynamic Impact Simulations

NASA Technical Reports Server (NTRS)

Fasanella, Edwin L.; Lyle, Karen H.; Jackson, Karen E.

2009-01-01

This paper describes fundamental soils characterization work performed at NASA Langley Research Center in support of the Subsonic Rotary Wing (SRW) Aeronautics Program and the Orion Landing System (LS) Advanced Development Program (ADP). LS-DYNA(Registered TradeMark)1 soil impact model development and test-analysis correlation results are presented for: (1) a 38-ft/s vertical drop test of a composite fuselage section, outfitted with four blocks of deployable energy absorbers (DEA), onto sand, and (2) a series of impact tests of a 1/2-scale geometric boilerplate Orion capsule onto soil. In addition, the paper will discuss LS-DYNA contact analysis at the soil/structure interface, methods used to estimate frictional forces, and the sensitivity of the model to density, moisture, and compaction.

Foliar Nutrient Distribution Patterns in Sympatric Maple Species Reflect Contrasting Sensitivity to Excess Manganese.

PubMed

Fernando, Denise R; Marshall, Alan T; Lynch, Jonathan P

2016-01-01

Sugar maple and red maple are closely-related co-occurring tree species significant to the North American forest biome. Plant abiotic stress effects including nutritional imbalance and manganese (Mn) toxicity are well documented within this system, and are implicated in enhanced susceptibility to biotic stresses such as insect attack. Both tree species are known to overaccumulate foliar manganese (Mn) when growing on unbuffered acidified soils, however, sugar maple is Mn-sensitive, while red maple is not. Currently there is no knowledge about the cellular sequestration of Mn and other nutrients in these two species. Here, electron-probe x-ray microanalysis was employed to examine cellular and sub-cellular deposition of excessively accumulated foliar Mn and other mineral nutrients in vivo. For both species, excess foliar Mn was deposited in symplastic cellular compartments. There were striking between-species differences in Mn, magnesium (Mg), sulphur (S) and calcium (Ca) distribution patterns. Unusually, Mn was highly co-localised with Mg in mesophyll cells of red maple only. The known sensitivity of sugar maple to excess Mn is likely linked to Mg deficiency in the leaf mesophyll. There was strong evidence that Mn toxicity in sugar maple is primarily a symplastic process. For each species, leaf-surface damage due to biotic stress including insect herbivory was compared between sites with acidified and non-acidified soils. Although it was greatest overall in red maple, there was no difference in biotic stress damage to red maple leaves between acidified and non-acidified soils. Sugar maple trees on buffered non-acidified soil were less damaged by biotic stress compared to those on unbuffered acidified soil, where they are also affected by Mn toxicity abiotic stress. This study concluded that foliar nutrient distribution in symplastic compartments is a determinant of Mn sensitivity, and that Mn stress hinders plant resistance to biotic stress.

Foliar Nutrient Distribution Patterns in Sympatric Maple Species Reflect Contrasting Sensitivity to Excess Manganese

PubMed Central

Fernando, Denise R.; Marshall, Alan T.; Lynch, Jonathan P.

2016-01-01

Sugar maple and red maple are closely-related co-occurring tree species significant to the North American forest biome. Plant abiotic stress effects including nutritional imbalance and manganese (Mn) toxicity are well documented within this system, and are implicated in enhanced susceptibility to biotic stresses such as insect attack. Both tree species are known to overaccumulate foliar manganese (Mn) when growing on unbuffered acidified soils, however, sugar maple is Mn-sensitive, while red maple is not. Currently there is no knowledge about the cellular sequestration of Mn and other nutrients in these two species. Here, electron-probe x-ray microanalysis was employed to examine cellular and sub-cellular deposition of excessively accumulated foliar Mn and other mineral nutrients in vivo. For both species, excess foliar Mn was deposited in symplastic cellular compartments. There were striking between-species differences in Mn, magnesium (Mg), sulphur (S) and calcium (Ca) distribution patterns. Unusually, Mn was highly co-localised with Mg in mesophyll cells of red maple only. The known sensitivity of sugar maple to excess Mn is likely linked to Mg deficiency in the leaf mesophyll. There was strong evidence that Mn toxicity in sugar maple is primarily a symplastic process. For each species, leaf-surface damage due to biotic stress including insect herbivory was compared between sites with acidified and non-acidified soils. Although it was greatest overall in red maple, there was no difference in biotic stress damage to red maple leaves between acidified and non-acidified soils. Sugar maple trees on buffered non-acidified soil were less damaged by biotic stress compared to those on unbuffered acidified soil, where they are also affected by Mn toxicity abiotic stress. This study concluded that foliar nutrient distribution in symplastic compartments is a determinant of Mn sensitivity, and that Mn stress hinders plant resistance to biotic stress. PMID:27391424

On the Holmberg asymmetry of the satellites of disk galaxies

NASA Technical Reports Server (NTRS)

Byrd, Gene G.; Valtonen, Mauri J.

1987-01-01

A tidal explanation for the observation by Holmberg that the satellites of edge-on disk galaxies tend to avoid the sector within + or - 30 deg of the major axes of the disk galaxies is considered. It is shown that satellites with small orbit-to-disk inclinations are likely to become compact and consequently be left out in Holmberg's survey due to the resemblance to stars. The explanation is supported by the observation of an excess of compact galaxies near the major-axis direction of edge-on disk galaxies. The disk tidal explanation also predicts that the asymmetry should be weaker with larger satellites. It is found that the Karachentsev (1972, 1980) binary galaxy sample, where the typical companion is comparable to the primary galaxy, shows no Holmberg effect. The case of M32 as a compact satellite of the Andromeda galaxy is discussed as a nearby observationally supported example of the above processes.

Effects of traffic-induced soil compaction on crop growth and soil properties

NASA Astrophysics Data System (ADS)

Baibay, Amélia; Ren, Lidong; D'Hose, Tommy; De Pue, Jan; Ruysschaert, Greet; Cornelis, Wim

2017-04-01

Traffic-induced soil compaction on arable soils constitutes a major threat for agricultural productivity and the environmental quality of the soil, water and atmosphere. The objective of this work is to evaluate a set of prevention strategies for agricultural traffic under real farming conditions. To that end, a one-pass traffic experiment was conducted near Ghent, Belgium in winter 2015 on a sandy loam (haplic Luvisol; 43% sand, 47% silt, 10% clay). Winter rye (Secale cereale L.), which promotes the removal of residual soil nitrogen and thus reduces the potential for nitrogen leaching, was sown as cover crop using different tractor and weather settings on different field lanes: dry (D, 0.16 m3 m-3) or wet (W, 0.20-0.23 m3 m-3) conditions, normal (N, 65 cm width, axle load 8520 kg) or wide (W, 90 cm width, axle load 8520 kg) tires and high (HP, 1.4 bars for N, 1.0 bar for W) or low (LP, 1.0 bar for N, 0.5 bar for W) inflation pressure. Subsequently, crop biomass, root density and a set of hydrophysical properties (penetration resistance, saturated hydraulic conductivity and water retention at 15, 35 and 55 cm depth) were measured. Bulk density, soil quality indicators (such as air capacity) and the pore size distribution were also calculated. Results showed significant biomass reduction (p < 0.01) for trafficked plots compared to their control (un-trafficked): 40% reduction under dry conditions and ˜80% under wet conditions. However, no differences were found between traffic treatments. A similar trend was observed for root density, though less significant. Under wet conditions, the rooting depth was also reduced (10 cm instead of 30 cm), and densities were very small. These results suggest a negative effect of compaction on crop growth, worse under wet conditions, but the choice of tires did not prove to have an effect. Observations on the hydrophysical properties were more mitigated, as expected: distinct differences are primarily found under controlled lab conditions or after several passes. Moreover, high moisture conditions could not be obtained for the wet experiment, which never exceeded field capacity, conceived as threshold. Nevertheless, penetration resistance profiles indicated a plough pan about 40 cm depth, witness of previous agricultural operations on the field, and high values (3.5 to 4 MPa) were found in the subsoil too. Moreover, bulk densities were higher for all treatments (up to 1.8 Mg m-3) compared to the controls (˜1.55 Mg m-3). Saturated hydraulic conductivities were very small (<< 10 cm/d), especially for the treatments. The dry treatment also showed better values than the wet ones at 15 cm. Water retention curves tended to show decreased water content at low suctions for the treatments (mainly at 15 cm), which could reflect on a reduction of macropores and their continuity. Soil quality parameters also showed better values in the control plots. These observations support an overall compacted state and loss of structural quality, though no significant impact of the traffic experiment or prevention strategies could be drawn.

Catchment hydrological change from soil degradation: A model study for assessing urbanization on the terrestrial water cycle

NASA Astrophysics Data System (ADS)

Shu, L.; Duffy, C.

2015-12-01

It is commonly held that land cover and land use changes from agriculture and urbanization impact the terrestrial water cycle primarily through changes in the land surface and canopy energy balance. Another, and in some cases more important factor is the role that landuse changes have on soil structure, compaction, and loss of carbon on hydrologic performance. The consequential change on soil properties, such as aggregation of soil particles, reduction of voids, impacts on matrix conductivity and macropore fractions, alter the hydrological processes in a watershed. Macropores promote rapid water and gas movement under wet conditions while the soil matrix preserves the water-holding capacity necessary for plant growth. The physically-based Penn State Integrated Hydrologic Model (PIHM) simulates water movement in soil with Richard's equation using an effective matrix-macropore conductivity. The model is able to capture the preferential flow and soil water storage in vertical and horizontal directions. Soil degradation leads to a reduction of the macropore fraction with dramatic changes in overall hydrologic performance under urban development and agricultural landuse practices. The effects on the terrestrial water cycle in the catchment reduce infiltration, soil water availability, recharge and subsurface baseflow to streams, while increasing heavy surface runoff and erosion. The Lancaster area and surrounding watershed in eastern Pennsylvania, USA is a benchmark watershed comprised of urban (24%), agricultural (58%) and forest lands (18%) respectively. After parameter estimation from national geospatial soils, landuse and historical climate reanalysis, three landuse scenarios were developed. 1) Pre-development forest landuse (<1700 AD), (2) deforestation for agriculture and light urban landuse (1700-1900), (3) urban-suburban development (1900-pres.). The watershed model was used to evaluate hydrologic changes due to landuse change and soil degradation. The effects of macropore reduction and compaction on hydrologic performance were found to be of the same order or greater magnitude than for changes in landuse practices alone. The research, funded by the US EPA, illustrates the complex interaction of landuse and soil changes on the terrestrial water cycle.

Germination and seedling development

USDA-ARS?s Scientific Manuscript database

Cottonseed germination and seedling development are highly sensitive to the environment at planting and for several weeks after that. Major factors that affect germination and development are temperature, water availability, soil conditions such as compaction, rhizosphere gases, and seed and seedlin...

The effects of green infrastructure on exceedance of critical shear stress in Blunn Creek watershed

NASA Astrophysics Data System (ADS)

Shannak, Sa'd.

2017-10-01

Green infrastructure (GI) has attracted city planners and watershed management professional as a new approach to control urban stormwater runoff. Several regulatory enforcements of GI implementation created an urgent need for quantitative information on GI practice effectiveness, namely for sediment and stream erosion. This study aims at investigating the capability and performance of GI in reducing stream bank erosion in the Blackland Prairie ecosystem. To achieve the goal of this study, we developed a methodology to represent two types of GI (bioretention and permeable pavement) into the Soil Water Assessment Tool, we also evaluated the shear stress and excess shear stress for stream flows in conjunction with different levels of adoption of GI, and estimated potential stream bank erosion for different median soil particle sizes using real and design storms. The results provided various configurations of GI schemes in reducing the negative impact of urban stormwater runoff on stream banks. Results showed that combining permeable pavement and bioretention resulted in the greatest reduction in runoff volumes, peak flows, and excess shear stress under both real and design storms. Bioretention as a stand-alone resulted in the second greatest reduction, while the installation of detention pond only had the least reduction percentages. Lastly, results showed that the soil particle with median diameter equals to 64 mm (small cobbles) had the least excess shear stress across all design storms, while 0.5 mm (medium sand) soil particle size had the largest magnitude of excess shear stress. The current study provides several insights into a watershed scale for GI planning and watershed management to effectively reduce the negative impact of urban stormwater runoff and control streambank erosion.

Critical Source Area Delineation: The representation of hydrology in effective erosion modeling.

NASA Astrophysics Data System (ADS)

Fowler, A.; Boll, J.; Brooks, E. S.; Boylan, R. D.

2017-12-01

Despite decades of conservation and millions of conservation dollars, nonpoint source sediment loading associated with agricultural disturbance continues to be a significant problem in many parts of the world. Local and national conservation organizations are interested in targeting critical source areas for control strategy implementation. Currently, conservation practices are selected and located based on the Revised Universal Soil Loss Equation (RUSLE) hillslope erosion modeling, and the National Resource Conservation Service will soon be transiting to the Watershed Erosion Predict Project (WEPP) model for the same purpose. We present an assessment of critical source areas targeted with RUSLE, WEPP and a regionally validated hydrology model, the Soil Moisture Routing (SMR) model, to compare the location of critical areas for sediment loading and the effectiveness of control strategies. The three models are compared for the Palouse dryland cropping region of the inland northwest, with un-calibrated analyses of the Kamiache watershed using publicly available soils, land-use and long-term simulated climate data. Critical source areas were mapped and the side-by-side comparison exposes the differences in the location and timing of runoff and erosion predictions. RUSLE results appear most sensitive to slope driving processes associated with infiltration excess. SMR captured saturation excess driven runoff events located at the toe slope position, while WEPP was able to capture both infiltration excess and saturation excess processes depending on soil type and management. A methodology is presented for down-scaling basin level screening to the hillslope management scale for local control strategies. Information on the location of runoff and erosion, driven by the runoff mechanism, is critical for effective treatment and conservation.

A spatial dynamic model to assess piospheric land degradation processes of SW Iberian rangelands

NASA Astrophysics Data System (ADS)

Herguido Sevillano, Estela; Ibáñez, Javier; Francisco Lavado Contador, Joaquín; Pulido-Fernández, Manuel; Schnabel, Susanne

2015-04-01

Iberian open wooded rangelands (known as dehesas or montados) constitute valuable agro-silvo-pastoral systems traditionally considered as highly sustainable. Nevertheless, in the recent decades, those systems are undergoing changes of land use and management practices that compromise its sustainability. Some of those changes, as the rising construction of watering points and the high spatial fragmentation and livestock movement restriction associated to fencing, show an aggregated effect with livestock, producing an impact gradient over soil and vegetation. Soil compaction related to livestock pressure is higher around watering points, with bare soil halos and patches of scarce vegetation or nude soil developing with higher frequency in areas close to them. Using the freeware Dinamica EGO as environmental modeling platform, we have developed a theoretic spatial dynamic model that represents some of the processes of land degradation associated to livestock grazing in dehesa fenced enclosures. Spatial resolution is high since every cell in the model is a square unit area of 1 m2. We paid particular attention to the relationships between soil degradation by compaction (porosity), livestock pressure, rainfall, pasture growth and shrub cover and bare soil generation. The model considers pasture growth as related to soil compaction, measured by the pore space in the top 10 cm soil layer. Annual precipitation is randomly generated following a normal distribution. When annual precipitation and pore space increase, also does pasture growth. Besides, there is a feedback between pasture growth and pore space, given that pasture roots increases soil porosity. The cell utility for livestock function has been defined as an exponential function of the distance of a cell to watering points and the amount of pasture present in it. The closer the cell to a pond and the higher the amount of pasture, the higher is cell utility. The latter is modulated by a normal random variable to capture accidental effects. This variable has zero mean and a standard deviation linearly related to the distance to the pond. Livestock utilization of a cell is a function of its relative utility, the stocking rate and the time that animals spend at the enclosure. Since livestock trampling promotes soil compaction, livestock utilization has a negative effect on pore space. The probability of transition from herbaceous to shrubs is also modulated by pore space, and thus livestock utilization, as shrub development needs a minimum porosity value for seeds to successfully germinate. In addition, it is influenced by the proportion of cells occupied by shrubs in a radius where seed dispersal or exclusion by competition may occur. The model contemplates the probability of transition from shrubs to herbaceous through shrub mortality, and the age of the shrubs, which influences seed production and shrub cover. Pasture consumption by livestock and pasture remaining at the end of summer were also modeled, so that it is possible to obtain maps of bare soil at that time. Likewise, the model generates maps of vegetation state (shrubs or herbaceous) and pasture growth. The values of the set of 31 parameters were obtained from field measurements and from publications. Those parameters lacking quantitative information were calibrated by comparing model performance with the dynamics of true enclosures analyzed between 1984 and 2009 in ortophotographs. Stocking rates were inferred from farmers' interviews performed in 2009 about present and past land use and management practices. The model developed is intended to analyze strategies of livestock management in dehesas. Particularly, soil conservation practices as related to livestock pressure can be simulated looking for optimized schemes. Moreover, the model provides the possibility of generating simulations for future climate scenarios, studying the effects of climate change on livestock carrying capacity on these systems. Thanks to the Spanish Ministerio de Economía y Competitividad for financially supporting this study through AMID (CGL2011-23361) project.

Assessing dry density and gravimetric water content of soils in geotechnics with complex conductivity measurements : preliminary investigations

NASA Astrophysics Data System (ADS)

Kaouane, C.; Beck, Y.; Fauchard, C.; Chouteau, M.

2012-12-01

Quality controls of geotechnical works need gravimetric water content (w) and dry density (γd) measurements. Afterwards, results are compared to Proctor tests and referred to soil classification. Depending on the class of soils, different objectives must be achieved. Those measurements are usually carried out with neutron and gamma probes. Combined use of theses probes directly access (w, γd). Theses probes show great disadvantages as: nuclear hazard, heavy on-site, transporation and storage restrictions and low sampling volumes. Last decades showed a strong development of electrical and electromagnetic methods for mapping water content in soils. Still, their use in Geotechnics is limited due to interfacial effects neglected in common models but strong in compacted soils. We first showed that (w, γd) is equivalent to (φ, Sr) assuming density of particles γs=2.7 (g.cm-3). This assumption is true for common soils used in civil engineering. That first relationship allows us to work with meaningful parameters for geophysicists. Revil&Florsh recently adapted Vinegar&Waxman model for Spectal Induced Polarization (SIP) measurements at low frequencies (<50 kHz). This model relates quantitatively the electrical double layer polarization at the surface of grains. It takes into account saturation, porosity and granulometry. Standard granulometry and mineralogy are generally available in geotechnical campaigns. In-phase conductivity would be mostly related to saturation as quadrature conductivity would be related to porosity and surface conductivity. Although this model was developed for oil-bearing sands, we investigated its potential for compacted soils. Former DC-resistivity (ρ) measurements were carried out on a silty fined-grained soil (A1 in GTR classification or ML-CL in USCS) in a cylindrical cell (radius ~4 cm, heigth 7 cm). Median diameter of grain was 50 μm. For each measurement, samples were compacted at Proctor energy. We assessed (w, γd) by weighting and drying samples. We obtained γd = 1.6-1.9 (g.cm-3) and w=7-14% which lead to φ=0.3-0.4 and Sr=0.3-0.8. Tap water (ρw= 30 Ω.m) was used for the experiment. We first evaluated the saturation factor n=1.35 by fitting a power law ρ/ρw =a*Sr^n+b. a=0.223 agreed with φ^(-n)=F, F being the formation factor. This leads to a mean tortuosity α=1.47. b=0.5 might be related to surface conductivity. An empirical Rhoades-Corwin model also fit great to data. Revil&Florsh model allows us to predict a phase peak in case of complex conductivity measurements. We predicted a frequency peak at 2.4 Hz. This peak is well located in the frequency range of SIP (from 1 mHz to ~10 Hz). At the frequency peak, this model allows the direct evaluation of saturation and porosity. Hence, complex conductivity measurements might be a fine alternative to nuclear probes. Still, driving in electrodes in compacted soils remains difficult. Ongoing studies are looking further to extend this model to higher frequency range (5-200 kHz) where capacitively coupled resistivity arrays might be used allowing continuous measurements.

Contrasting the effects of organic matter removal and soil compaction on root biomass of 9-year-old red oak, white oak, and shortleaf pine in a Missouri Ozark forest

Treesearch

Felix Jr. Ponder

2011-01-01

Nine-year old artificially regenerated red oak (Quercus rubra L.), white oak (Q. alba L.), and shortleaf pine (Pinus echinata Mill.) trees were excavated from plot borders of a U.S. Forest Service long-term soil productivity study in the Carr Creek State Forest near Ellington, MO, to quantify treatment effects on...

Soil aggregation and slope stability related to soil density, root length, and mycorrhiza

NASA Astrophysics Data System (ADS)

Graf, Frank; Frei, Martin

2013-04-01

Eco-engineering measures combine the use of living plants and inert mechanical constructions to protect slopes against erosion and shallow mass movement. Whereas in geotechnical engineering several performance standards and guidelines for structural safety and serviceability of construction exist, there is a lack of comparable tools in the field of ecological restoration. Various indicators have been proposed, including the fractal dimension of soil particle size distribution, microbiological parameters, and soil aggregate stability. We present results of an soil aggregate stability investigation and compare them with literature data of the angle of internal friction ?' which is conventionally used in slope stability analysis and soil failure calculation. Aggregate stability tests were performed with samples of differently treated moraine, including soil at low (~15.5 kN/m³) and high (~19.0 kN/m³) dry unit weight, soil planted with Alnus incana (White Alder) as well as the combination of soil planted with alder and inoculated with the mycorrhizal fungus Melanogaster variegatus s.l. After a 20 weeks growth period in a greenhouse, a total of 100 samples was tested and evaluated. Positive correlations were found between the soil aggregate stability and the three variables dry unit weight, root length per soil volume, and degree of mycorrhization. Based on robust statistics it turned out that dry unit weight and mycorrhization degree were strongest correlated with soil aggregate stability. Compared to the non-inoculated control plants, mycorrhized White Alder produced significantly more roots and higher soil aggregate stability. Furthermore, the combined biological effect of plant roots and mycorrhizal mycelia on aggregate stability on soil with low density (~15.5 kN/m³) was comparable to the compaction effect of the pure soil from 15.5 to ~19.0 kN/m³. Literature data on the effect of vegetation on the angle of internal friction ?' of the same moraine showed similar correlations, i.e. that ?' of low density soil material (~15.5 kN/m³) increased by the same amount whether by planting with White Alder or by compaction to ~19.0 kN/m³. Based on this coincidence the method to quantify soil aggregate produced satisfying results which indicate that soil aggregate stability is a potential proxy for ?' and the joint impact of mycorrhizal fungi and plant roots increase the resistance against superficial soil failure. It is concluded that soil aggregate stability mirrors biological effects on soil stability reasonably well and may be used as an indicator to quantify the effectiveness of ecological restoration and stabilisation measures.

Boron- and salt-tolerant trees and shrubs for northern Nevada

Treesearch

Heidi Kratsch

2012-01-01

Boron is a mineral that, in small quantities, is essential for plant growth and development , but becomes toxic at levels above 0.5 to 1 part per million (ppm) in the soil. Excess boron may be naturally present in the soil, and it can accumulate by irrigating with water high in boron. Boron occurs naturally in arid soils originating from geologically young deposits. It...

A GIS based estimation of loss of particulate nitrogen and phosphorus in typical drainage area of Pearl River Delta

NASA Astrophysics Data System (ADS)

Liu, Xiaonan; Wu, Zhifeng; Cheng, Jiong; Liu, Ping

2008-10-01

The output of nitrogen and phosphorus from agricultural activities is the main source for water eutrophication. The fully developed agriculture in vegetables, fruits and flowers in Pearl River Delta gives rise to excessive use of chemical matter such as fertilizer and pesticide and thus bring about the serious water pollution because of the loss of nitrogen (N) and phosphorus (P) from the farmland in the region. Based on Geographic Information System (GIS) and soil pollution data, Universal Soil Loss Equation (USLE) and source type method are used to estimate the loads of particulate N and P from the soil of different land use types in the drainage area of Liuxi River in Guangzhou, China. So the key regions those the NPS pollution occurred can be confirmed and the technical support for the pollution control target and the capital flow concentration can be provided by the results. The study shows that, (1) The total loss of particulate N and P in the drainage area is 582.49 t/a and 424.74 t/a respectively. Among them the loss of particulate N from paddy soil occupies 40.02% and that of forest 6.31%, while the loss of particulate P from the soil of dry-land accounts for 28.75% and that of paddy soil 26.31%. (2) There are significantly different losses of particulate N and P per unit area from the soils of different source land use types in the drainage area. The losses of particulate N and P per unit area are both the highest from the soil of dry-land, which is 7.72 kg/hm2 and 9.50 kg/hm2 respectively, followed by those of orchard, which is 7.20 kg/hm2 and 6.56 kg/hm2 respectively. The causes are excessive use of chemical matter, unreasonable cultivation pattern, and the soil erosion of different land use. (3) The excessive N and P come from the loss of particulate N and P from the fertilization in agricultural production, and they are the main source of the pollutants in Liuxi River water.

Capacity and degree of iodine absorbed and enriched by vegetable from soil.

PubMed

Weng, Huan-Xin; Weng, Jing-Ke; Yong, Wen-Bin; Sun, Xiang-Wu; Zhong, Hang

2003-01-01

To understand the biogeochemical transfer of iodine, the absorbability and bioaccumulation of iodine in tested vegetables (radish, spinach and Chinese cabbage) are examined by applying iodic fertilizer composed of kelp and diatomaceous earth. The experimental results show that when iodine in soil is not excessive, the concentrations of iodine in tested vegetables increase as the content of iodine in soil increases. The absorbability and enrichment degree of iodine in various vegetables and in various parts of the same vegetable a redifferent, which explains that the concentration of iodine in plant is determined by the plant type and the physiological action of plant. The patience order of tested vegetables to excessive iodine is Chinese cabbage > spinach > radish. These results have theoretical and practical significance in opening up a new way for ameliorating poor iodine environment with artificial means.

Snowmelt and Infiltration Deficiencies of SSiB and Their Resolution with a New Snow-Physics Scheme

NASA Technical Reports Server (NTRS)

Sud, Y. C.; Mocko, David M.

1999-01-01

A two-year 1987-1988 integration of SSiB forced with ISLSCP Initiative I surface data (as part of the Global Soil Wetness Project, GSWP, evaluation and intercomparison) produced generally realistic land surface fluxes and hydrology. Nevertheless, the evaluation also helped to identify some of the deficiencies of the current version of the Simplified Simple Biosphere (SSiB) model. The simulated snowmelt was delayed in most regions, along with excessive runoff and lack of an spring soil moisture recharge. The SSIB model had previously been noted to have a problem producing accurate soil moisture as compared to observations in the Russian snowmelt region. Similarly, various GSWP implementations of SSIB found deficiencies in this region of the simulated soil moisture and runoff as compared to other non-SSiB land-surface models (LSMs). The origin of these deficiencies was: 1) excessive cooling of the snow and ground, and 2) deep frozen soil disallowing snowmelt infiltration. The problem was most severe in regions that experience very cold winters. In SSiB, snow was treated as a unified layer with the first soil layer, causing soil and snow to cool together in the winter months, as opposed to snow cover acting as an insulator. In the spring season, a large amount of heat was required to thaw a hard frozen snow plus deep soil layers, delaying snowmelt and causing meltwater to become runoff over the frozen soil rather than infiltrate into it.

Role of macropore flow in the transport of Escherichia coli cells in undisturbed cores of a brown leached soil.

PubMed

Martins, Jean M F; Majdalani, Samer; Vitorge, Elsa; Desaunay, Aurélien; Navel, Aline; Guiné, Véronique; Daïan, Jean François; Vince, Erwann; Denis, Hervé; Gaudet, Jean Paul

2013-02-01

The objective of this work was to evaluate the transport of Escherichia coli cells in undisturbed cores of a brown leached soil collected at La Côte St André (France). Two undisturbed soil cores subjected to repeated injections of bacterial cells and/or bromide tracer were used to investigate the effect of soil hydrodynamics and ionic strength on cell mobility. Under the tested experimental conditions, E. coli cells were shown to be transported at the water velocity (retardation factor close to 1) and their retention appeared almost insensitive to water flow and ionic strength variations, both factors being known to control bacterial transport in model saturated porous media. In contrast, E. coli breakthrough curves evolved significantly along with the repetition of the cell injections in each soil core, with a progressive acceleration of their transport. The evolution of E. coli cells BTCs was shown to be due to the evolution of the structure of soil hydraulic pathways caused by the repeated water infiltrations and drainage as may occur in the field. This evolution was demonstrated through mercury intrusion porosimetry (MIP) performed on soil aggregates before and after the repeated infiltrations of bacteria. MIP revealed a progressive and important reduction of the soil aggregate porosity, n, that decreased from approximately 0.5 to 0.3, along with a decrease of the soil percolating step from 27 to 2 μm. From this result a clear compaction of soil aggregates was evidenced that concerned preferentially the pores larger than 2 μm equivalent diameter, i.e. those allowing bacterial cell passage. Since no significant reduction of the global soil volume was observed at the core scale, this aggregate compaction was accompanied by macropore formation that became progressively the preferential hydraulic pathway in the soil cores, leading to transiently bi-modal bacterial BTCs. The evolution of the soil pore structure induced a modification of the main hydrodynamic processes, evolving from a matrix-dominant transfer of water and bacteria to a macropore-dominant transfer. This work points out the importance of using undisturbed natural soils to evaluate the mobility of bacteria in the field, since the evolving hydrodynamic properties of soils appeared to dominate most physicochemical factors.

Non-motorized winter recreation impacts to snowmelt erosion, Tronsen Basin, Eastern Cascades, Washington.

PubMed

Eagleston, Holly; Rubin, Charles

2013-01-01

Many recreation impact studies have focused on summer activities, but the environmental impact of winter recreation is poorly characterized. This study characterizes the impact of snowshoe/cross-country ski compaction and snowmelt erosion on trails. Trail cross-sectional profiles were measured before and after the winter season to map changes in erosion due to winter recreation. Compacted snow on the trail was 30 % more dense than snowpack off the trail before spring melt out. Snow stayed on the trail 7 days longer. Soil and organic material was transported after spring snowmelt with -9.5 ± 2.4 cm(2) total erosion occurring on the trail transects and -3.8 ± 2.4 cm(2) total erosion occurring on the control transect (P = 0.046). More material was transported on the trail than on the control, 12.9± 2.4 versus 6.0 ± 2.4 cm(2) (P = 0.055), however, deposition levels remained similar on the trail and on the control. Snow compaction from snowshoers and cross-country skiers intensified erosion. Trail gradient was found to be significantly correlated to net changes in material on the trail (R (2) = 0.89, ρ = -0.98, P = 0.005). This study provides a baseline, showing that non-motorized winter recreation does impact soil erosion rates but more studies are needed. Trail managers should consider mitigation such as water bars, culverts and avoiding building trails with steep gradients, in order to reduce loss of soils on trails and subsequent sedimentation of streams.

Non-motorized Winter Recreation Impacts to Snowmelt Erosion, Tronsen Basin, Eastern Cascades, Washington

NASA Astrophysics Data System (ADS)

Eagleston, Holly; Rubin, Charles

2013-01-01

Many recreation impact studies have focused on summer activities, but the environmental impact of winter recreation is poorly characterized. This study characterizes the impact of snowshoe/cross-country ski compaction and snowmelt erosion on trails. Trail cross-sectional profiles were measured before and after the winter season to map changes in erosion due to winter recreation. Compacted snow on the trail was 30 % more dense than snowpack off the trail before spring melt out. Snow stayed on the trail 7 days longer. Soil and organic material was transported after spring snowmelt with -9.5 ± 2.4 cm2 total erosion occurring on the trail transects and -3.8 ± 2.4 cm2 total erosion occurring on the control transect ( P = 0.046). More material was transported on the trail than on the control, 12.9± 2.4 versus 6.0 ± 2.4 cm2 ( P = 0.055), however, deposition levels remained similar on the trail and on the control. Snow compaction from snowshoers and cross-country skiers intensified erosion. Trail gradient was found to be significantly correlated to net changes in material on the trail ( R 2 = 0.89, ρ = -0.98, P = 0.005). This study provides a baseline, showing that non-motorized winter recreation does impact soil erosion rates but more studies are needed. Trail managers should consider mitigation such as water bars, culverts and avoiding building trails with steep gradients, in order to reduce loss of soils on trails and subsequent sedimentation of streams.

Integrated watershed management for saturation excess generated runoff, erosion and nutrient control

USDA-ARS?s Scientific Manuscript database

Understanding the basic hydrology and erosion is vital for effective management and utilization of water resources and soil conservation planning. An important question for judging effectiveness of soil and water conservation practices is whether runoff erosion and nutrient loss is affected by infil...

Biodiversity and Ecosystem Multi-Functionality: Observed Relationships in Smallholder Fallows in Western Kenya

PubMed Central

Sircely, Jason; Naeem, Shahid

2012-01-01

Recent studies indicate that species richness can enhance the ability of plant assemblages to support multiple ecosystem functions. To understand how and when ecosystem services depend on biodiversity, it is valuable to expand beyond experimental grasslands. We examined whether plant diversity improves the capacity of agroecosystems to sustain multiple ecosystem services—production of wood and forage, and two elements of soil formation—in two types of smallholder fallows in western Kenya. In 18 grazed and 21 improved fallows, we estimated biomass and quantified soil organic carbon, soil base cations, sand content, and soil infiltration capacity. For four ecosystem functions (wood biomass, forage biomass, soil base cations, steady infiltration rates) linked to the focal ecosystem services, we quantified ecosystem service multi-functionality as (1) the proportion of functions above half-maximum, and (2) mean percentage excess above mean function values, and assessed whether plant diversity or environmental favorability better predicted multi-functionality. In grazed fallows, positive effects of plant diversity best explained the proportion above half-maximum and mean percentage excess, the former also declining with grazing intensity. In improved fallows, the proportion above half-maximum was not associated with soil carbon or plant diversity, while soil carbon predicted mean percentage excess better than diversity. Grazed fallows yielded stronger evidence for diversity effects on multi-functionality, while environmental conditions appeared more influential in improved fallows. The contrast in diversity-multi-functionality relationships among fallow types appears related to differences in management and associated factors including disturbance and species composition. Complementary effects of species with contrasting functional traits on different functions and multi-functional species may have contributed to diversity effects in grazed fallows. Biodiversity and environmental favorability may enhance the capacity of smallholder fallows to simultaneously provide multiple ecosystem services, yet their effects are likely to vary with fallow management. PMID:23209662

Non-invasive analysis of root-soil interaction using three complementary imaging approaches

NASA Astrophysics Data System (ADS)

Haber-Pohlmeier, Sabina; Tötzke, Christian; Pohlmeier, Andreas; Rudolph-Mohr, Nicole; Kardjilov, Nikolay; Lehmann, Eberhard; Oswald, Sascha E.

2016-04-01

Plant roots are known to modify physical, chemical and biological properties of the rhizosphere, thereby, altering conditions for water and nutrient uptake. We aim for capturing the dynamic processes occurring at the soil-root interface in situ. A combination of neutron (NI), magnetic resonance (MRI) and micro-focus X-ray tomography (CT) is applied to monitor the rhizosphere of young plants grown in sandy soil in cylindrical containers (diameter 3 cm). A novel transportable low field MRI system is operated directly at the neutron facility allowing for combined measurements of the very same sample capturing the same hydro-physiological state. The combination of NI, MRI and CT provides three-dimensional access to the root system in respect to structure and hydraulics of the rhizosphere and the transport of dissolved marker substances. The high spatial resolution of neutron imaging and its sensitivity for water can be exploited for the 3D analysis of the root morphology and detailed mapping of three-dimensional water content at the root soil interface and the surrounding soil. MRI has the potential to yield complementary information about the mobility of water, which can be bound in small pores or in the polymeric network of root exudates (mucilage layer). We inject combined tracers (GdDPTA or D2O) to study water fluxes through soil, rhizosphere and roots. Additional CT measurements reveal mechanical impacts of roots on the local microstructure of soil, e.g. showing soil compaction or the formation of cracks. We co-register the NT, MRI and CT data to integrate the complementary information into an aligned 3D data set. This allows, e.g., for co-localization of compacted soil regions or cracks with the specific local soil hydraulics, which is needed to distinguish the contribution of root exudation from mechanical impacts when interpreting altered hydraulic properties of the rhizosphere. Differences between rhizosphere and bulk soil can be detected and interpreted in terms of root growth, root exudation, and root water uptake. Thus, we demonstrate that such a multi-imaging approach can be used as powerful tool contributing to a more comprehensive picture of the rhizosphere.

The Influences of Soil Characteristics on Nest-Site Selection in Painted Turtles (Chrysemys picta)

NASA Astrophysics Data System (ADS)

Page, R.

2017-12-01

A variety of animals dig nests and lay their eggs in soil, leaving them to incubate and hatch without assistance from the parents. Nesting habitat is important for these organisms many of which exhibit temperature dependent sex determination (TSD) whereby the incubation temperature determines the sex of each hatchling. However, suitable nesting habitat may be limited due to anthropogenic activities and global temperature increases. Soil thermal properties are critical to these organisms and are positively correlated with water retention and soil carbon; carbon-rich soils result in higher incubation temperatures. We investigated nest-site selection in painted turtles (Chrysemys picta) inhabiting an anthropogenic pond in south central Pennsylvania. We surveyed for turtle nests and documented location, depth, width, temperature, canopy coverage, clutch size, and hatch success for a total of 31 turtle nests. To address the influence of soil carbon and particle size on nest selection, we analyzed samples collected from: 1) actual nests that were depredated, 2) false nests, incomplete nests aborted during digging prior to nest completion, and 3) randomized locations. Soil samples were separated into coarse, medium, and fine grain size fractions through a stack of sieves. Samples were combusted in a total carbon analyzer to measure weight percent organic carbon. We found that anthropogenic activity at this site has created homogenous, sandy, compacted soils at the uppermost layer that may limit females' access to appropriate nesting habitat. Turtle nesting activity was limited to a linear region north of the pond and was constrained by an impassable rail line. Relative to other studies, turtle nests were notably shallow (5.8±0.9 cm) and placed close to the pond. Compared to false nests and random locations, turtle-selected sites averaged greater coarse grains (35% compared to 20.24 and 20.57%) and less fine grains (47% compared to 59 and 59, respectively). Despite remarkably high soil carbon along the rail line (47.08%) turtles nested here with slightly higher hatch success. We suggest that the turtles are limited to sandy, compact soils with low heat capacities and may compensate for this by also nesting adjacent to the rail line where high soil carbon could increase incubation temperatures.

The effect of changing land use on soil radiocarbon

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

Harrison, K.G.; Broecker, W.S.; Bonani, G.

Most carbon budgets require greening of the terrestrial biosphere as a sink for some of the excess carbon dioxide produced by fossil fuel burning and deforestation. Much of this storage is thought to occur in soils, but running counter to this conclusion is the observation that cultivation has reduced the agricultural reservoir of soil humus. Radiocarbon measurements in agricultural soils lend support to this browning of agricultural lands. Moreover, the loss is from the fast cycling portion of the humus.

Toward Green Challenge Courses.

ERIC Educational Resources Information Center

Johnson, Karl E.

1999-01-01

Designing environmentally friendly challenge courses involves considering factors such as clearing, trees versus poles, soil erosion and compaction, toilet design, waste disposal, and carrying capacity. Strategies used in "green development" such as systems thinking, solution multipliers, and brainstorming with stakeholders could promote…

30 CFR 817.71 - Disposal of excess spoil: General requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

.... (1) All vegetative and organic materials shall be removed from the disposal area prior to placement... § 817.22. If approved by the regulatory authority, organic material may be used as mulch or may be... of the soil. (2) Excess spoil shall be transported and placed in a controlled manner in horizontal...

30 CFR 817.71 - Disposal of excess spoil: General requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

.... (1) All vegetative and organic materials shall be removed from the disposal area prior to placement... § 817.22. If approved by the regulatory authority, organic material may be used as mulch or may be... of the soil. (2) Excess spoil shall be transported and placed in a controlled manner in horizontal...

30 CFR 817.71 - Disposal of excess spoil: General requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

.... (1) All vegetative and organic materials shall be removed from the disposal area prior to placement... § 817.22. If approved by the regulatory authority, organic material may be used as mulch or may be... of the soil. (2) Excess spoil shall be transported and placed in a controlled manner in horizontal...

30 CFR 816.71 - Disposal of excess spoil: General requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

.... (1) All vegetative and organic materials shall be removed from the disposal area prior to placement... with § 816.22. If approved by the regulatory authority, organic material may be used as mulch or may be... of the soil. (2) Excess spoil shall be transported and placed in a controlled manner in horizontal...

30 CFR 816.71 - Disposal of excess spoil: General requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

.... (1) All vegetative and organic materials shall be removed from the disposal area prior to placement... with § 816.22. If approved by the regulatory authority, organic material may be used as mulch or may be... of the soil. (2) Excess spoil shall be transported and placed in a controlled manner in horizontal...

30 CFR 816.71 - Disposal of excess spoil: General requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

.... (1) All vegetative and organic materials shall be removed from the disposal area prior to placement... with § 816.22. If approved by the regulatory authority, organic material may be used as mulch or may be... of the soil. (2) Excess spoil shall be transported and placed in a controlled manner in horizontal...

30 CFR 816.71 - Disposal of excess spoil: General requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

.... (1) All vegetative and organic materials shall be removed from the disposal area prior to placement... with § 816.22. If approved by the regulatory authority, organic material may be used as mulch or may be... of the soil. (2) Excess spoil shall be transported and placed in a controlled manner in horizontal...

30 CFR 816.71 - Disposal of excess spoil: General requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

.... (1) All vegetative and organic materials shall be removed from the disposal area prior to placement... with § 816.22. If approved by the regulatory authority, organic material may be used as mulch or may be... of the soil. (2) Excess spoil shall be transported and placed in a controlled manner in horizontal...

30 CFR 817.71 - Disposal of excess spoil: General requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

.... (1) All vegetative and organic materials shall be removed from the disposal area prior to placement... § 817.22. If approved by the regulatory authority, organic material may be used as mulch or may be... of the soil. (2) Excess spoil shall be transported and placed in a controlled manner in horizontal...

30 CFR 817.71 - Disposal of excess spoil: General requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

.... (1) All vegetative and organic materials shall be removed from the disposal area prior to placement... § 817.22. If approved by the regulatory authority, organic material may be used as mulch or may be... of the soil. (2) Excess spoil shall be transported and placed in a controlled manner in horizontal...

Manure and nitrogen application enhances soil phosphorus mobility in calcareous soil in greenhouses.

PubMed

Yan, Zhengjuan; Chen, Shuo; Li, Junliang; Alva, Ashok; Chen, Qing

2016-10-01

Over many years, high phosphorus (P) loading for intensive vegetable cropping in greenhouses of North China has contributed to excessive P accumulation, resulting in environmental risk. In this study, the influences of manure and nitrogen (N) application on the transformation and transport of soil P were investigated after nine years in a greenhouse tomato double cropping system (winter-spring and autumn-winter seasons). High loading of manure significantly increased the soil inorganic P (Pi), inositol hexakisphosphate (IHP), mobile P and P saturation ratio (PSR, >0.7 in 0-30 cm depth soil; PSR was estimated from P/(Fe + Al) in an oxalate extract of the soil). The high rate of N fertilizer application to the studied calcareous soil with heavy loading of manure increased the following: (i) mobile organic P (Po) and Pi fractions, as evidenced by the decrease in the ratio of monoesters to diesters and the proportion of stable Pi (i.e., HCl-Pi) in total P (Pt) in 0-30 cm depth soil; (ii) relative distribution of Po in the subsoil layer; and (iii) P leaching to soil depths below 90 cm and the proportion of Po in Pt in the leachate. More acidic soil due to excessive N application increased P mobility and leaching. The increase in Ox-Al (oxalate-extractable Al) and the proportion of microbe-associated Po related to N application at soil depths of 0-30 cm suggested decrease in the net Po mineralization, which may contribute to downward transport of Po in the soil profile. Copyright © 2016 Elsevier Ltd. All rights reserved.

Application of the Modified Compaction Material Model to the Analysis of Landmine Detonation in Soil with Various Degrees of Water Saturation

DTIC Science & Technology

2007-01-01

Equation of State R2 – Constant in JWL Equation of State σ – Yield Stress T – Temperature...v – Specific volume w – Constant in JWL Equation of State x – Spatial coordinate y – Spatial coordinate Y – Yield stress Subscripts Comp – Value at...Constant in JWL Equation of State α – Porosity B – Compaction Modulus B1 – Strain Hardening Constant B2 – Constant in JWL Equation of State

Design of novel SOI 1 × 4 optical power splitter using seven horizontally slotted waveguides

NASA Astrophysics Data System (ADS)

Katz, Oded; Malka, Dror

2017-07-01

In this paper, we demonstrate a compact silicon on insulator (SOI) 1 × 4 optical power splitter using seven horizontal slotted waveguides. Aluminum nitride (AIN) surrounded by silicon (Si) was used to confine the optical field in the slot region. All of the power analysis has been done in transverse magnetic (TM) polarization mode and a compact optical power splitter as short as 14.5 μm was demonstrated. The splitter was designed by using full vectorial beam propagation method (FV-BPM) simulations. Numerical investigations show that this device can work across the whole C-band (1530-1565 nm) with excess loss better than 0.23 dB.

Demonstration of Single-Shot Picosecond Time-Resolved MeV Electron Imaging Using a Compact Permanent Magnet Quadrupole Based Lens

NASA Astrophysics Data System (ADS)

Cesar, D.; Maxson, J.; Musumeci, P.; Sun, Y.; Harrison, J.; Frigola, P.; O'Shea, F. H.; To, H.; Alesini, D.; Li, R. K.

2016-07-01

We present the results of an experiment where a short focal length (˜1.3 cm ), permanent magnet electron lens is used to image micron-size features (of a metal sample) with a single shot from an ultrahigh brightness picosecond-long 4 MeV electron beam emitted by a radio-frequency photoinjector. Magnification ratios in excess of 30 × were obtained using a triplet of compact, small gap (3.5 mm), Halbach-style permanent magnet quadrupoles with nearly 600 T /m field gradients. These results pave the way towards single-shot time-resolved electron microscopy and open new opportunities in the applications of high brightness electron beams.

Nitrous oxide emissions from soil amended with low-phosphorus broiler litter

USDA-ARS?s Scientific Manuscript database

Regions of the United States with a high concentration of poultry farms have soils with excess nitrogen (N) and phosphorus (P) far beyond the agronomic requirement of crops because of recurrent land application of broiler litter. A new waste treatment technology developed by USDA-ARS, called “Quick ...

Phosphorus recovery prior to land application of biosolids using the "quick wash" process developed by USDA

USDA-ARS?s Scientific Manuscript database

Excess soil phosphorus (P) beyond the assimilative capacity of soils is a major factor to discontinue application of biosolids to land nearby municipal wastewater treatment plants. For this reason, municipalities incur in hefty fees for transportation and landfilling biosolids that otherwise could b...

Pore-water pressures associated with clogging of soil pipes: Numerical analysis of laboratory experiments

USDA-ARS?s Scientific Manuscript database

Clogging of soil pipes due to excessive internal erosion has been hypothesized to cause extreme erosion events such as landslides, debris flows, and gullies, but confirmation of this phenomenon has been lacking. Laboratory and field measurements have failed to measure pore water pressures within pip...