Science.gov

Sample records for air soil vegetation

  1. Evolution of HTO concentrations in soil, vegetation and air during an experimental chronic HT release

    SciTech Connect

    Davis, P.A.; Galeriu, D.C.; Spencer, F.S.; Amiro, B.D.

    1995-10-01

    A small experimental plot was continuously exposed to elevated levels of HT in air over a 12-day period to study the build up and steady-state concentrations of HTO in the environment. HTO concentrations in soil, vegetation and air all showed similar dynamics, increasing gradually over time with temporary decreases during and following rainfall. The relative magnitudes of the soil, vegetation and air concentrations depended on the height at which the air and vegetation were sampled, the depth at which the soil sample was taken and the soil depth over which the plants drew their transpiration water. The system was at or near steady-state in the last two or three days of the release. When averaged over an eight day interval that included periods of rain, the ratios of HTO concentration in soil, foliage and air moisture to HT concentration in air (measured 20 cm above the ground) were typically 0.0014, 0.0010 and 0.0011 (Bq/mL)/(Bq/m{sup 3}) for a cultivated field. 10 refs., 7 figs.

  2. Radionuclide transport from soil to air, native vegetation, kangaroo rats and grazing cattle on the Nevada test site

    SciTech Connect

    Gilbert, R.O.; Shinn, J.H.; Essington, E.H.; Tamura, T.; Romney, E.M.; Moor, K.S.; O'Farrell, T.P.

    1988-12-01

    Between 1970 and 1986 the Nevada Applied Ecology Group (NAEG), U.S. Department of Energy, conducted environmental radionuclide studies at weapons-testing sites on or adjacent to the Nevada Test Site. In this paper, NAEG studies conducted at two nuclear (fission) sites (NS201, NS219) and two nonnuclear (nonfission) sites (Area 13 (Project 57) and Clean Slate 2) are reviewed, synthesized and compared regarding (1) soil particle-size distribution and physical-chemical characteristics of 239 + 240Pu-bearing radioactive particles, (2) 239 + 240Pu resuspension rates and (3) transuranic and fission-product radionuclide transfers from soil to native vegetation, kangaroo rats and grazing cattle. The data indicate that transuranic radionuclides were transferred more readily on the average from soil to air, the external surfaces of native vegetation and to tissues of kangaroo rats at Area 13 than at NS201 or NS219. The 239 + 240Pu resuspension factor for undisturbed soil at Area 13 was three to four orders-of-magnitude larger than at NS201 and NS219, the geometric mean (GM) vegetation-over-soil 239 + 240Pu concentration ratio was from ten to 100 times larger than at NS201, and the GM GI-over-soil, carcass-over-soil and pelt-over-soil 239 + 240Pu ratios for kangaroo rats were about ten times larger than at NS201. These results are consistent with the finding that Area 13, compared with NS201 or NS219, has a higher percentage of radioactivity associated with smaller soil particles and a larger percentage of resuspendable and respirable soil. However, the resuspension factor increased by a factor of 27 at NS201 when the surface soil was disturbed, and by a factor of 12 at NS219 following a wildfire.

  3. Soil and vegetation surveillance

    SciTech Connect

    Antonio, E.J.

    1995-06-01

    Soil sampling and analysis evaluates long-term contamination trends and monitors environmental radionuclide inventories. This section of the 1994 Hanford Site Environmental Report summarizes the soil and vegetation surveillance programs which were conducted during 1994. Vegetation surveillance is conducted offsite to monitor atmospheric deposition of radioactive materials in areas not under cultivation and onsite at locations adjacent to potential sources of radioactivity.

  4. Radionuclide transport from soil to air, native vegetation, kangaroo rats and grazing cattle on the Nevada test site.

    PubMed

    Gilbert, R O; Shinn, J H; Essington, E H; Tamura, T; Romney, E M; Moor, K S; O'Farrell, T P

    1988-12-01

    Between 1970 and 1986 the Nevada Applied Ecology Group (NAEG), U.S. Department of Energy, conducted environmental radionuclide studies at weapons-testing sites on or adjacent to the Nevada Test Site. In this paper, NAEG studies conducted at two nuclear (fission) sites (NS201, NS219) and two nonnuclear (nonfission) sites (Area 13 [Project 57] and Clean Slate 2) are reviewed, synthesized and compared regarding (1) soil particle-size distribution and physical-chemical characteristics of 239 + 240Pu-bearing radioactive particles, (2) 239 + 240Pu resuspension rates and (3) transuranic and fission-product radionuclide transfers from soil to native vegetation, kangaroo rats and grazing cattle. The data indicate that transuranic radionuclides were transferred more readily on the average from soil to air, the external surfaces of native vegetation and to tissues of kangaroo rats at Area 13 than at NS201 or NS219. The 239 + 240Pu resuspension factor for undisturbed soil at Area 13 was three to four orders-of-magnitude larger than at NS201 and NS219, the geometric mean (GM) vegetation-over-soil 239 + 240Pu concentration ratio was from ten to 100 times larger than at NS201, and the GM GI-over-soil, carcass-over-soil and pelt-over-soil 239 + 240Pu ratios for kangaroo rats were about ten times larger than at NS201. These results are consistent with the finding that Area 13, compared with NS201 or NS219, has a higher percentage of radioactivity associated with smaller soil particles and a larger percentage of resuspendable and respirable soil. However, the resuspension factor increased by a factor of 27 at NS201 when the surface soil was disturbed, and by a factor of 12 at NS219 following a wildfire. The average (GM) concentration of 239 + 240Pu for the GI (and contents) of Area 13 kangaroo rats and for the rumen contents of beef cattle that grazed Area 13 were very similar (400 vs. 440 Bq kg-1 dry wt, respectively) although the variability between individuals was very large. The

  5. Predicting bioconcentration of chemicals into vegetation from soil or air using the molecular connectivity index

    SciTech Connect

    Dowdy, D.L.; McKone, T.E.; Hsieh, D.P.H.

    1995-12-31

    Bioconcentration factors (BCFs) are the ratio of chemical concentration found in an exposed organism (in this case a plant) to the concentration in an air or soil exposure medium. The authors examine here the use of molecular connectivity indices (MCIs) as quantitative structure-activity relationships (QSARS) for predicting BCFs for organic chemicals between plants and air or soil. The authors compare the reliability of the octanol-air partition coefficient (K{sub oa}) to the MC based prediction method for predicting plant/air partition coefficients. The authors also compare the reliability of the octanol/water partition coefficient (K{sub ow}) to the MC based prediction method for predicting plant/soil partition coefficients. The results here indicate that, relative to the use of K{sub ow} or K{sub oa} as predictors of BCFs the MC can substantially increase the reliability with which BCFs can be estimated. The authors find that the MC provides a relatively precise and accurate method for predicting the potential biotransfer of a chemical from environmental media into plants. In addition, the MC is much faster and more cost effective than direct measurements.

  6. Vegetation and soils

    USGS Publications Warehouse

    Burke, M.K.; King, S.L.; Eisenbies, M.H.; Gartner, D.

    2000-01-01

    Intro paragraph: Characterization of bottomland hardwood vegetation in relatively undisturbed forests can provide critical information for developing effective wetland creation and restoration techniques and for assessing the impacts of management and development. Classification is a useful technique in characterizing vegetation because it summarizes complex data sets, assists in hypothesis generation about factors influencing community variation, and helps refine models of community structure. Hierarchical classification of communities is particularly useful for showing relationships among samples (Gauche 1982).

  7. [Monitoring of heavy metals and trace elements in the air, fruits and vegetables and soil in the province of Catania (Italy)].

    PubMed

    Ferrante, Margherita; Fiore, Maria; Ledda, Caterina; Cicciù, Francesca; Alonzo, Elena; Fallico, Roberto; Platania, Francesco; Di Mauro, Rosario; Valenti, Lina; Sciacca, Salvatore

    2013-01-01

    Contamination of fruits and vegetables with heavy metals can result from anthropogenic events (car or factory emissions, poor management of sewage and industrial waste) or from natural events (volcanic activity and geological soil matrix). The chemical and toxicological characteristics of heavy metals can have an impact on human health through several mechanisms. Other metals, on the other hand, are essential for maintenance of physiological and biochemical human processes, are protective against many diseases and must be present in the diet because they cannot be synthesized by the human body. The purpose of this study was to assess the presence of heavy metals and trace elements both in fruit and vegetable products widely consumed in the province of Catania (Sicily, Italy) and in various environmental matrices (air, water and land), and to investigate possible sources of contamination. Fruit and vegetable products (tomatoes, lettuce, spinach, eggplants, potatoes, zucchini, grapes, apples and pears) were sampled (n = 60) from the towns of Adrano, Biancavilla and Mazzarrone. These locations were selected for their geomorphology, climate and cultivation characteristics. Levels of lead, cadmium, nickel, copper, zinc, vanadium and selenium in fruit, vegetables, air and water samples were determined using atomic absorption spectrometer with graphite furnace Perkin-Elmer AAnalyst 800 while soil samples were evaluated by the atomic emission spectrometer Optima 2000 DV Perkin-Elmer. The presence of mercury was evaluated by atomic absorption spectrometry with cold vapor technique. Study results revealed widespread contamination of fruit and vegetables and mainly due to use of fertilizers and to volcanic activity. A strategy targeting the entire food chain is essential for ensuring food safety and consumer protection and maintaining contaminants at levels which are not hazardous to health.

  8. Soil temperature depressions beneath vegetation

    SciTech Connect

    Starkweather, S.

    1996-10-01

    The results from a summer-long monitoring project were used to determine the effects of vegetative cover on soil temperatures and ground heat fluxes. The measurements were taken over three months in a residential neighborhood adjacent to the University of Colorado campus and correlated with data from a weather station located a mile away. By contrasting the soil temperatures beneath a moderately shaded, vegetated site to those beneath an open site covered with turf grass, the authors were able to quantify an added energy saving benefit of alternative landscapes and tree planting; reduced summer-time ground heat flux. The results from the monitoring project were used to develop a general model for relating local weather data and site-specific vegetative morphologies to site-specific ground heat fluxes. The authors found that the reduced ground heat flux can be largely attributed to the reduced net radiation flux arriving at the soil surface.

  9. Chloroacetic acids in European soils and vegetation.

    PubMed

    Peters, Ruud J B

    2003-04-01

    Trichloroacetic acid (TCA) and dichloroacetic acid (DCA) are possible minor atmospheric degradation products of perchloroethylene and trichloroethylene, respectively. These acids may be wet- or dry-deposited from the atmosphere to land surfaces and hence possibly affect plant growth. However, the existing database on TCA levels in soil is limited to a few studies carried out in the late 1980's and the early to mid-1990's and it was concluded that there is a need for further measurements of concentrations of TCA and DCA in soils. In this study soil samples from 10 locations in 5 European countries, as well as vegetation samples, and a limited number of rainwater and air samples were collected and analysed for DCA and TCA to determine the concentrations of these compounds. An isotope dilution method using GC-MS was used for the determination of these acids in the samples. The method was briefly validated and the performance characteristics are presented. The results of the analysis of the soil samples show that the DCA and TCA concentrations in soil from different sites in Europe are more or less comparable, with the exception of Germany, especially Freudenstadt, where significantly higher TCA concentrations (up to 12 microg kg(-1) dw) were found. The average DCA and TCA concentrations in soil in this study were 0.25 +/- 0.12 and 0.64 +/- 1.40 microg kg(-1) dw, respectively. Generally, the concentration in soils from forest areas are about twice those from open-land areas. The DCA and TCA concentrations in vegetation samples ranged from 2.1 to 73 microg kg(-1) dw for DCA and from 4.7 to 17 microg kg(-1) dw for TCA. Thus, the concentrations in vegetation samples are 10-20 times higher than the soil concentrations. DCA and TCA concentrations in wet deposition samples and air samples collected in The Netherlands were 0.14 and 0.15 microg l(-1) for wet deposition samples and <0.5 and 0.7 ng m(-3) for air samples respectively. For these samples taken in The Netherlands

  10. Preliminary assessment of soil moisture over vegetation

    NASA Technical Reports Server (NTRS)

    Carlson, T. N.

    1986-01-01

    Modeling of surface energy fluxes was combined with in-situ measurement of surface parameters, specifically the surface sensible heat flux and the substrate soil moisture. A vegetation component was incorporated in the atmospheric/substrate model and subsequently showed that fluxes over vegetation can be very much different than those over bare soil for a given surface-air temperature difference. The temperature signatures measured by a satellite or airborne radiometer should be interpreted in conjunction with surface measurements of modeled parameters. Paradoxically, analyses of the large-scale distribution of soil moisture availability shows that there is a very high correlation between antecedent precipitation and inferred surface moisture availability, even when no specific vegetation parameterization is used in the boundary layer model. Preparatory work was begun in streamlining the present boundary layer model, developing better algorithms for relating surface temperatures to substrate moisture, preparing for participation in the French HAPEX experiment, and analyzing aircraft microwave and radiometric surface temperature data for the 1983 French Beauce experiments.

  11. Residues of organophosphate pesticides used in vegetable cultivation in ambient air, surface water and soil in Bueng Niam Subdistrict, Khon Kaen, Thailand.

    PubMed

    Harnpicharnchai, Kallaya; Chaiear, Naesinee; Charerntanyarak, Lertchai

    2013-11-01

    Agricultural pesticide utilization is one of the important problems in rural and urban crop-cultivated areas, with the majority of pollutants dispersing via ambient air, water and other natural pathways. This study was therefore conducted in a specially selected village which is known to be a leading vegetable growing area in Khon Kaen Province. The aim of the study was to assess pesticide residues, and measure the seasonal fluctuations in organophosphate concentrations during 2010 in the environment of a risk area. Samples from selected sites were collected in two phases: Phase I was in summer (during March to May) and Phase II was in winter (during October to December). A total of 150 samples were analyzed using gas chromatography with flame photometric detection. The results showed that dicrotophos, chlorpyrifos, profenofos and ethion were found at the highest concentrations in soil and at the lowest concentrations in ambient air (p<0.001). The highest mean concentration of a pesticide in ambient air samples was 0.2580 +/- 0.2686 mg/m(3) for chlorpyrifos in summer and 0.1003 +/- 0.0449 mg/m(3) for chlorpyrifos in winter. In surface water samples, the highest mean concentration of a pesticide was 1.3757 +/- 0.5014 mg/l for dicrotophos in summer and 0.3629 +/- 0.4338 mg/l for ethion in winter. The highest mean concentration of a pesticide in soil samples was 42.2893 +/- 39.0711 mg/kg ethion in summer and 90.0000 +/- 24.1644 mg/kg of ethion in winter.

  12. A novel low-cost open-hardware platform for monitoring soil water content and multiple soil-air-vegetation parameters.

    PubMed

    Bitella, Giovanni; Rossi, Roberta; Bochicchio, Rocco; Perniola, Michele; Amato, Mariana

    2014-10-21

    Monitoring soil water content at high spatio-temporal resolution and coupled to other sensor data is crucial for applications oriented towards water sustainability in agriculture, such as precision irrigation or phenotyping root traits for drought tolerance. The cost of instrumentation, however, limits measurement frequency and number of sensors. The objective of this work was to design a low cost "open hardware" platform for multi-sensor measurements including water content at different depths, air and soil temperatures. The system is based on an open-source ARDUINO microcontroller-board, programmed in a simple integrated development environment (IDE). Low cost high-frequency dielectric probes were used in the platform and lab tested on three non-saline soils (ECe1: 2.5 < 0.1 mS/cm). Empirical calibration curves were subjected to cross-validation (leave-one-out method), and normalized root mean square error (NRMSE) were respectively 0.09 for the overall model, 0.09 for the sandy soil, 0.07 for the clay loam and 0.08 for the sandy loam. The overall model (pooled soil data) fitted the data very well (R2 = 0.89) showing a high stability, being able to generate very similar RMSEs during training and validation (RMSE(training) = 2.63; RMSE(validation) = 2.61). Data recorded on the card were automatically sent to a remote server allowing repeated field-data quality checks. This work provides a framework for the replication and upgrading of a customized low cost platform, consistent with the open source approach whereby sharing information on equipment design and software facilitates the adoption and continuous improvement of existing technologies.

  13. A Novel Low-Cost Open-Hardware Platform for Monitoring Soil Water Content and Multiple Soil-Air-Vegetation Parameters

    PubMed Central

    Bitella, Giovanni; Rossi, Roberta; Bochicchio, Rocco; Perniola, Michele; Amato, Mariana

    2014-01-01

    Monitoring soil water content at high spatio-temporal resolution and coupled to other sensor data is crucial for applications oriented towards water sustainability in agriculture, such as precision irrigation or phenotyping root traits for drought tolerance. The cost of instrumentation, however, limits measurement frequency and number of sensors. The objective of this work was to design a low cost “open hardware” platform for multi-sensor measurements including water content at different depths, air and soil temperatures. The system is based on an open-source ARDUINO microcontroller-board, programmed in a simple integrated development environment (IDE). Low cost high-frequency dielectric probes were used in the platform and lab tested on three non-saline soils (ECe1: 2.5 < 0.1 mS/cm). Empirical calibration curves were subjected to cross-validation (leave-one-out method), and normalized root mean square error (NRMSE) were respectively 0.09 for the overall model, 0.09 for the sandy soil, 0.07 for the clay loam and 0.08 for the sandy loam. The overall model (pooled soil data) fitted the data very well (R2 = 0.89) showing a high stability, being able to generate very similar RMSEs during training and validation (RMSEtraining = 2.63; RMSEvalidation = 2.61). Data recorded on the card were automatically sent to a remote server allowing repeated field-data quality checks. This work provides a framework for the replication and upgrading of a customized low cost platform, consistent with the open source approach whereby sharing information on equipment design and software facilitates the adoption and continuous improvement of existing technologies. PMID:25337742

  14. Green vegetation, nonphotosynthetic vegetation, and soils in AVIRIS data

    NASA Technical Reports Server (NTRS)

    Roberts, D. A.; Smith, M. O.; Adams, J. B.

    1993-01-01

    The problem of distinguishing between green vegetation, nonphotosynthetic vegetation (NPV, such as dry grass, leaf litter, and woody material), and soils in imaging-spectrometer data is addressed by analyzing an image taken by the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) over the Jasper Ridge Biological Preserve (California) on September 20, 1989, using spectral mixture analysis. Over 98 percent of the spectral variation could be explained by linear mixtures of three endmembers, green vegetation, shade, and soil. NPV, which could not be distinguished from soil when included as an endmember, was discriminated by residual spectra that contained cellulose and lignin absorptions. Distinct communities of green vegetation were distinguished by (1) nonlinear mixing effect caused by transmission and scattering by green leaves, (2) variations in a derived canopy-shade spectrum, and (3) the fraction of NPV.

  15. Radar for Measuring Soil Moisture Under Vegetation

    NASA Technical Reports Server (NTRS)

    Moghaddam, Mahta; Moller, Delwyn; Rodriguez, Ernesto; Rahmat-Samii, Yahya

    2004-01-01

    A two-frequency, polarimetric, spaceborne synthetic-aperture radar (SAR) system has been proposed for measuring the moisture content of soil as a function of depth, even in the presence of overlying vegetation. These measurements are needed because data on soil moisture under vegetation canopies are not available now and are necessary for completing mathematical models of global energy and water balance with major implications for global variations in weather and climate.

  16. Surface Environmental Surveillance Project: Locations Manual Volume 1 – Air and Water Volume 2 – Farm Products, Soil & Vegetation, and Wildlife

    SciTech Connect

    Fritz, Brad G.; Patton, Gregory W.; Stegen, Amanda; Poston, Ted M.

    2009-01-01

    This report describes all environmental monitoring locations associated with the Surface Environmental Surveillance Project. Environmental surveillance of the Hanford site and surrounding areas is conducted by the Pacific Northwest National Laboratory (PNNL) for the U.S. Department of Energy (DOE). Sampling is conducted to evaluate levels of radioactive and nonradioactive pollutants in the Hanford environs, as required in DOE Order 450.1, Environmental Protection Program, and DOE Order 5400.5, Radiation Protection of the Public and the Environment. The environmental surveillance sampling design is described in the Hanford Site Environmental Monitoring Plan, United States Department of Energy, Richland Operation Office (DOE/RL-91-50). This document contains the locations of sites used to collect samples for the Surface Environmental Surveillance Project (SESP). Each section includes directions, maps, and pictures of the locations. A general knowledge of roads and highways on and around the Hanford Site is necessary to successfully use this manual. Supplemental information (Maps, Gazetteer, etc.) may be necessary if user is unfamiliar with local routes. The SESP is a multimedia environmental surveillance effort to measure the concentrations of radionuclides and chemicals in environmental media to demonstrate compliance with applicable environmental quality standards and public exposure limits, and assessing environmental impacts. Project personnel annually collect selected samples of ambient air, surface water, agricultural products, fish, wildlife, and sediments. Soil and vegetation samples are collected approximately every 5 years. Analytical capabilities include the measurement of radionuclides at very low environmental concentrations and, in selected media, nonradiological chemicals including metals, anions, volatile organic compounds, and total organic carbon.

  17. Correspondence between vegetation and soils in wetlands and nearby uplands

    USGS Publications Warehouse

    Scott, Michael L.; Slauson, William L.; Segelquist, Charles A.; Auble, Gregor T.

    1989-01-01

    The association between vegetation and soils from a geographically broad sampling of wetlands and adjoining uplands is reported for 38 hydric and 26 nonhydric soils, as recognized in the hydric soils list of the Soil Conservation Service. Wetlands represented in the study include estuaries, pitcher plant bogs, prairie depressional wetlands, and western riparian lands. The agreement between vegetation and soils is clear with few exceptions. In general, hydric soils support hydrophytic plant communities, and nonhydric soils support upland communities. Only 10% of the hydric soils sampled support upland communities and only 15% of the nonhydric soils support wetland communities. Exceptions to the correspondence between vegetation and soils are discussed; local hydrology, the transitional nature of some soils, and other determinants of wetland vegetation structure (e.g., salinity, disturbance) seem to account for many of the observed discrepancies. A method that simplifies the complexity of soils and vegetation cannot be expected to represent accurately all details of their interrelations.

  18. Vegetative soil covers for hazardous waste landfills

    NASA Astrophysics Data System (ADS)

    Peace, Jerry L.

    Shallow land burial has been the preferred method for disposing of municipal and hazardous wastes in the United States because it is the simplest, cheapest, and most cost-effective method of disposal. Arid and semiarid regions of the western United States have received considerable attention over the past two decades in reference to hazardous, radioactive, and mixed waste disposal. Disposal is based upon the premise that low mean annual precipitation, high evapotranspiration, and low or negligible recharge, favor waste isolation from the environment for long periods of time. The objective of this study is to demonstrate that containment of municipal and hazardous wastes in arid and semiarid environments can be accomplished effectively without traditional, synthetic materials and complex, multi-layer systems. This research demonstrates that closure covers utilizing natural soils and native vegetation i.e., vegetative soil covers, will meet the technical equivalency criteria prescribed by the U.S. Environmental Protection Agency for hazardous waste landfills. Vegetative soil cover design combines layers of natural soil, native plant species, and climatic conditions to form a sustainable, functioning ecosystem that maintains the natural water balance. In this study, percolation through a natural analogue and an engineered cover is simulated using the one-dimensional, numerical code UNSAT-H. UNSAT-H is a Richards' equation-based model that simulates soil water infiltration, unsaturated flow, redistribution, evaporation, plant transpiration, and deep percolation. This study incorporates conservative, site-specific soil hydraulic and vegetation parameters. Historical meteorological data from 1919 to 1996 are used to simulate percolation through the natural analogue and an engineered cover, with and without vegetation. This study indicates that a 1 m (3 ft) cover is the minimum design thickness necessary to meet the U.S. Environmental Protection Agency

  19. Variation in the urban vegetation, surface temperature, air temperature nexus.

    PubMed

    Shiflett, Sheri A; Liang, Liyin L; Crum, Steven M; Feyisa, Gudina L; Wang, Jun; Jenerette, G Darrel

    2017-02-01

    Our study examines the urban vegetation - air temperature (Ta) - land surface temperature (LST) nexus at micro- and regional-scales to better understand urban climate dynamics and the uncertainty in using satellite-based LST for characterizing Ta. While vegetated cooling has been repeatedly linked to reductions in urban LST, the effects of vegetation on Ta, the quantity often used to characterize urban heat islands and global warming, and on the interactions between LST and Ta are less well characterized. To address this need we quantified summer temporal and spatial variation in Ta through a network of 300 air temperature sensors in three sub-regions of greater Los Angeles, CA, which spans a coastal to desert climate gradient. Additional sensors were placed within the inland sub-region at two heights (0.1m and 2m) within three groundcover types: bare soil, irrigated grass, and underneath citrus canopy. For the entire study region, we acquired new imagery data, which allowed calculation of the normalized difference vegetation index (NDVI) and LST. At the microscale, daytime Ta measured along a vertical gradient, ranged from 6 to 3°C cooler at 0.1 and 2m, underneath tall canopy compared to bare ground respectively. At the regional scale NDVI and LST were negatively correlated (p<0.001). Relationships between diel variation in Ta and daytime LST at the regional scale were progressively weaker moving away from the coast and were generally limited to evening and nighttime hours. Relationships between NDVI and Ta were stronger during nighttime hours, yet effectiveness of mid-day vegetated cooling increased substantially at the most arid region. The effectiveness of vegetated Ta cooling increased during heat waves throughout the region. Our findings suggest an important but complex role of vegetation on LST and Ta and that vegetation may provide a negative feedback to urban climate warming.

  20. Remote sensing of vegetation and soil moisture

    NASA Technical Reports Server (NTRS)

    Kong, J. A.; Shin, R. T. (Principal Investigator)

    1983-01-01

    Progress in the investigation of problems related to the remote sensing of vegetation and soil moisture is reported. Specific topics addressed include: (1) microwave scattering from periodic surfaces using a rigorous modal technique; (2) combined random rough surface and volume scattering effects; (3) the anisotropic effects of vegetation structures; (4) the application of the strong fluctuation theory to the the study of electromagnetic wave scattering from a layer of random discrete scatterers; and (5) the investigation of the scattering of a plane wave obliquely incident on a half space of densely distributed spherical dielectric scatterers using a quantum mechanical potential approach.

  1. Heat Waves, Urban Vegetation, and Air Pollution

    NASA Astrophysics Data System (ADS)

    Churkina, G.; Grote, R.; Butler, T. M.

    2014-12-01

    Fast-track programs to plant millions of trees in cities around the world aim at the reduction of summer temperatures, increase carbon storage, storm water control, provision of space for recreation, as well as poverty alleviation. Although these multiple benefits speak positively for urban greening programs, the programs do not take into account how close human and natural systems are coupled in urban areas. Elevated temperatures together with anthropogenic emissions of air and water pollutants distinguish the urban system. Urban and sub-urban vegetation responds to ambient changes and reacts with pollutants. Neglecting the existence of this coupling may lead to unforeseen drawbacks of urban greening programs. The potential for emissions from urban vegetation combined with anthropogenic emissions to produce ozone has long been recognized. This potential increases under rising temperatures. Here we investigate how global change induced heat waves affect emissions of volatile organic compounds (VOC) from urban vegetation and corresponding ground-level ozone levels. We also quantify other ecosystem services provided by urban vegetation (e.g., cooling and carbon storage) and their sensitivity to climate change. In this study we use Weather Research and Forecasting Model with coupled atmospheric chemistry (WRF-CHEM) to quantify these feedbacks in Berlin, Germany during the heat waves in 2003 and 2006. We highlight the importance of the vegetation for urban areas under changing climate and discuss associated tradeoffs.

  2. PIXE, 252Cf-PDMS and radiochemistry applied for soil and vegetable analysis

    NASA Astrophysics Data System (ADS)

    Dias da Cunha, K.; Cazicava, J.; Coelho, M. J.; Barros Leite, C. V.

    2006-01-01

    The aim of this work is to identify the elements present in vegetables and soils using PIXE (particle induced X-rays emission) and 252Cf-PDMS (252Cf plasma desorption mass spectrometry) techniques in order to estimate the possible influence of soil and agricultural techniques in the metal absorption by the vegetables. In this work, metal concentrations were evaluated in soil and vegetable samples from several regions, where different agricultural techniques were employed. Si, Zr, Ce, Th, Sc and Pb identified in the soil samples were not biologically available. Ga, Ge, As and Br identified in the tubercles indicate that spray pesticide used on the vegetable leaves was absorbed by them. 232Th and 238U present in the soil were not absorbed by the vegetables. The airborne particles from anthropogenic sources (as CFn, VCn) were absorbed by the vegetables. Compounds from mineral sources present in soil as V+, VCO3, HPO4, Cr+, CrOH+, Mn+, FeH+, Fe(OH)n and in the bioorganic compounds as N+, Ca (CN)n+and CnH+ were identified in vegetables. The metal absorption by the vegetables is not dependent of the metal concentration in soil. Different tubercles cultivated in the same soil show similar metal absorption. The exogenous contributions such as the elements present in water irrigation, pesticides, fertilizers and airborne particles deposited on leaves can be absorbed by vegetables. The absorption by the roots depends on the chemical compound of the elements. The use of pesticide sprays and air pollution can cause more contamination in the vegetables than in soil. The use of this methodology allows the identification of possible sources of metals in soils and in vegetables and the metal speciation.

  3. Air pollution and its influence on vegetation: Causes - Effects - Prophylaxis and therapy

    SciTech Connect

    Dassler, H.G.; Bortitz, S.

    1988-01-01

    This book presents a survey about air pollution from power stations, industry, traffic and other anthroponegic sources together with its effects on vegetation. It provides information on chronic and acute effects of air pollution in agriculture, horticulture, and forestry (including soil and animals), on symptoms of damage, immission tolerance, bioindication, methods of air and plant analysis and especially on prophylaxis and therapy in air polluted areas and on landscape planning.

  4. Reflectance of vegetation, soil, and water

    NASA Technical Reports Server (NTRS)

    Wiegand, C. L. (Principal Investigator)

    1973-01-01

    The author has identified the following significant results. The ability to read the 24-channel MSS CCT tapes, select specified agricultural land use areas from the CCT, and perform multivariate statistical and pattern recognition analyses has been demonstrated. The 5 optimum channels chosen for classifying an agricultural scene were, in the order of their selection the far red visible, short reflective IR, visible blue, thermal infrared, and ultraviolet portions of the electromagnetic spectrum, respectively. Although chosen by a training set containing only vegetal categories, the optimum 4 channels discriminated pavement, water, bare soil, and building roofs, as well as the vegetal categories. Among the vegetal categories, sugar cane and cotton had distinctive signatures that distinguished them from grass and citrus. Acreages estimated spectrally by the computer for the test scene were acceptably close to acreages estimated from aerial photographs for cotton, sugar cane, and water. Many nonfarmable land resolution elements representing drainage ditch, field road, and highway right-of-way as well as farm headquarters area fell into the grass, bare soil plus weeds, and citrus categories and lessened the accuracy of the farmable acreage estimates in these categories. The expertise developed using the 24-channel data will be applied to the ERTS-1 data.

  5. Reflectance of vegetation, soil, and water

    NASA Technical Reports Server (NTRS)

    Wiegand, C. L.; Gausman, H. W.; Leamer, R. W.; Richardson, A. J.; Gerbermann, A. H. (Principal Investigator)

    1974-01-01

    The author has identified the following significant results. Iron deficient and normal grain sorghum plants were sufficiently different spectrally in ERTS-1 band 5 CCT data to detect chlorotic sorghum areas 2.8 acres (1.1 hectares) or larger in size in computer printouts of the MSS data. The ratio of band 5 to band 7 or band 7 minus band 5 relates to vegetation ground cover conditions and helps to select training samples representative of differing vegetation maturity or vigor classes and to estimate ground cover or green vegetation density in the absence of ground information. The four plant parameters; leaf area index, plant population, plant cover, and plant height explained 87 to 93% of the variability in band 6 digital counts and from 59 to 90% of the variation in bands 4 and 5. A ground area 2244 acres in size was classified on a pixel by pixel basis using simultaneously acquired aircraft support and ERTS-1 data. Overall recognition for vegetables, immature crops and mixed shrubs, and bare soil categories was 64.5% for aircraft and 59.6% for spacecraft data, respectively. Overall recognition results on a per field basis were 61.8% for aircraft and 62.8% for ERTS-1 data.

  6. Reflectance of vegetation, soil, and water

    NASA Technical Reports Server (NTRS)

    Wiegand, C. L. (Principal Investigator)

    1974-01-01

    The author has identified the following significant results. The Kubelka-Munk model, a regression model, and a combination of these models were used to extract plant, soil, and shadow reflectance components of vegetated surfaces. The combination model was superior to the others; it explained 86% of the variation in band 5 reflectance of corn and sorghum, and 90% of the variation in band 6 reflectance of cotton. A fractional shadow term substantially increased the proportion of the digital count sum of squares explained when plant parameters alone explained 85% or less of the variation. Overall recognition of 94 agricultural fields using simultaneously acquired aircraft and spacecraft MSS data was 61.8 and 62.8%, respectively; recognition of vegetable fields larger than 10 acres and taller than 25 cm, rose to 88.9 and 100% for aircraft and spacecraft, respectively. Agriculture and rangeland, were well discriminated for the entire county but level 2 categories of vegetables, citrus, and idle cropland, except for citrus, were not.

  7. Vegetation study in support of the design and optimization of vegetative soil covers, Sandia National Laboratories, Albuquerque, New Mexico.

    SciTech Connect

    Peace, Gerald L.; Goering, Timothy James (GRAM inc., Albuquerque, NM); Knight, Paul J. (Marron and Associates, Albuquerque, NM); Ashton, Thomas S. (Marron and Associates, Albuquerque, NM)

    2004-11-01

    A vegetation study was conducted in Technical Area 3 at Sandia National Laboratories, Albuquerque, New Mexico in 2003 to assist in the design and optimization of vegetative soil covers for hazardous, radioactive, and mixed waste landfills at Sandia National Laboratories/New Mexico and Kirtland Air Force Base. The objective of the study was to obtain site-specific, vegetative input parameters for the one-dimensional code UNSAT-H and to identify suitable, diverse native plant species for use on vegetative soil covers that will persist indefinitely as a climax ecological community with little or no maintenance. The identification and selection of appropriate native plant species is critical to the proper design and long-term performance of vegetative soil covers. Major emphasis was placed on the acquisition of representative, site-specific vegetation data. Vegetative input parameters measured in the field during this study include root depth, root length density, and percent bare area. Site-specific leaf area index was not obtained in the area because there was no suitable platform to measure leaf area during the 2003 growing season due to severe drought that has persisted in New Mexico since 1999. Regional LAI data was obtained from two unique desert biomes in New Mexico, Sevilletta Wildlife Refuge and Jornada Research Station.

  8. Interactive Vegetation Phenology, Soil Moisture, and Monthly Temperature Forecasts

    NASA Technical Reports Server (NTRS)

    Koster, R. D.; Walker, G. K.

    2015-01-01

    The time scales that characterize the variations of vegetation phenology are generally much longer than those that characterize atmospheric processes. The explicit modeling of phenological processes in an atmospheric forecast system thus has the potential to provide skill to subseasonal or seasonal forecasts. We examine this possibility here using a forecast system fitted with a dynamic vegetation phenology model. We perform three experiments, each consisting of 128 independent warm-season monthly forecasts: 1) an experiment in which both soil moisture states and carbon states (e.g., those determining leaf area index) are initialized realistically, 2) an experiment in which the carbon states are prescribed to climatology throughout the forecasts, and 3) an experiment in which both the carbon and soil moisture states are prescribed to climatology throughout the forecasts. Evaluating the monthly forecasts of air temperature in each ensemble against observations, as well as quantifying the inherent predictability of temperature within each ensemble, shows that dynamic phenology can indeed contribute positively to subseasonal forecasts, though only to a small extent, with an impact dwarfed by that of soil moisture.

  9. A nonlinear coupled soil moisture-vegetation model

    NASA Astrophysics Data System (ADS)

    Liu, Shikuo; Liu, Shida; Fu, Zuntao; Sun, Lan

    2005-06-01

    Based on the physical analysis that the soil moisture and vegetation depend mainly on the precipitation and evaporation as well as the growth, decay and consumption of vegetation a nonlinear dynamic coupled system of soil moisture-vegetation is established. Using this model, the stabilities of the steady states of vegetation are analyzed. This paper focuses on the research of the vegetation catastrophe point which represents the transition between aridness and wetness to a great extent. It is shown that the catastrophe point of steady states of vegetation depends mainly on the rainfall P and saturation value v0, which is selected to balance the growth and decay of vegetation. In addition, when the consumption of vegetation remains constant, the analytic solution of the vegetation equation is obtained.

  10. A new approach to predict soil temperature under vegetated surfaces.

    PubMed

    Dolschak, Klaus; Gartner, Karl; Berger, Torsten W

    2015-12-01

    In this article, the setup and the application of an empirical model, based on Newton's law of cooling, capable to predict daily mean soil temperature (Tsoil) under vegetated surfaces, is described. The only input variable, necessary to run the model, is a time series of daily mean air temperature. The simulator employs 9 empirical parameters, which were estimated by inverse modeling. The model, which primarily addresses forested sites, incorporates the effect of snow cover and soil freezing on soil temperature. The model was applied to several temperate forest sites, managing the split between Central Europe (Austria) and the United States (Harvard Forest, Massachusetts; Hubbard Brook, New Hampshire), aiming to cover a broad range of site characteristics. Investigated stands differ fundamentally in stand composition, elevation, exposition, annual mean temperature, precipitation regime, as well as in the duration of winter snow cover. At last, to explore the limits of the formulation, the simulator was applied to non-forest sites (Illinois), where soil temperature was recorded under short cut grass. The model was parameterized, specifically to site and measurement depth. After calibration of the model, an evaluation was performed, using ~50 % of the available data. In each case, the simulator was capable to deliver a feasible prediction of soil temperature in the validation time interval. To evaluate the practical suitability of the simulator, the minimum amount of soil temperature point measurements, necessary to yield expedient model performance was determined. In the investigated case 13-20 point observations, uniformly distributed within an 11-year timeframe, have been proven sufficient to yield sound model performance (root mean square error <0.9 °C, Nash-Sutcliffe efficiency >0.97). This makes the model suitable for the application on sites, where the information on soil temperature is discontinuous or scarce.

  11. Does urban vegetation mitigate air pollution in northern conditions?

    PubMed

    Setälä, Heikki; Viippola, Viljami; Rantalainen, Anna-Lea; Pennanen, Arto; Yli-Pelkonen, Vesa

    2013-12-01

    It is generally accepted that urban vegetation improves air quality and thereby enhances the well-being of citizens. However, empirical evidence on the potential of urban trees to mitigate air pollution is meager, particularly in northern climates with a short growing season. We studied the ability of urban park/forest vegetation to remove air pollutants (NO2, anthropogenic VOCs and particle deposition) using passive samplers in two Finnish cities. Concentrations of each pollutant in August (summer; leaf-period) and March (winter, leaf-free period) were slightly but often insignificantly lower under tree canopies than in adjacent open areas, suggesting that the role of foliage in removing air pollutants is insignificant. Furthermore, vegetation-related environmental variables (canopy closure, number and size of trees, density of understorey vegetation) did not explain the variation in pollution concentrations. Our results suggest that the ability of urban vegetation to remove air pollutants is minor in northern climates.

  12. Retrieving Vegetation Parameters and Soil Reflection Coefficients with P-band SAR Polarimetry

    NASA Astrophysics Data System (ADS)

    Alemohammad, S. H.; Konings, A. G.; Jagdhuber, T.; Entekhabi, D.

    2015-12-01

    Photosynthetic activity of plants is highly dependent on the water available to the plant through its roots. Therefore, measuring the root-zone-soil-moisture across large spatial scales is of great importance for crop monitoring and yield estimation as well as hydrological and ecological modeling. Unlike L-band instruments, which are sensitive to only a few centimeters of the top soil layer, P-band Synthetic Aperture Radar (SAR) instruments have a penetration depth that can be used to retrieve soil moisture profiles in depths of several tens of centimeters (depending on soil texture and moisture content). NASA's Airborne Microwave Observatory of Subcanopy and Subsurface (AirMOSS) mission is designed to study the application of P-band SAR measurements for monitoring root-zone-soil-moisture. In this study, we introduce a new framework to retrieve vegetation parameters and smooth-surface soil reflection coefficients using SAR polarimetry and the fully polarimetric covariance matrix of the backscattering signal from AirMOSS observations. The retrieved soil reflectivities (both horizontally and vertically -polarized) can then be used to estimate the soil moisture profile. The retrieval model takes into account contributions from surface, dihedral and volume scattering coming from the vegetation and soil components, and does not require prior vegetation parameters. This approach reduces the dependency of the retrieval on allometry-based vegetation models with large numbers of uncertain parameters. The performance of this method will be validated using observations from AirMOSS field campaigns in July 2013 over Harvard Forest in Massachusetts, USA. This will enable a quality assessment of the polarimetry-based retrieval of the soil reflectivities and the estimated root-zone-soil-moisture profiles.

  13. Soil microbial properties under different vegetation types on Mountain Han.

    PubMed

    Wang, Miao; Qu, Laiye; Ma, Keming; Yuan, Xiu

    2013-06-01

    This study investigated the influence of broadleaf and conifer vegetation on soil microbial communities in a distinct vertical distribution belt in Northeast China. Soil samples were taken at 0-5, 5-10 and 10-20 cm depths from four vegetation types at different altitudes, which were characterized by poplar (Populus davidiana) (1250-1300 m), poplar (P. davidiana) mixed with birch (Betula platyphylla) (1370-1550 m), birch (B. platyphylla) (1550-1720 m), and larch (Larix principis-rupprechtii) (1840-1890 m). Microbial biomass and community structure were determined using the fumigation-extraction method and phospholipid fatty acid (PLFA) analysis, and soil fungal community level physiological profiles (CLPP) were characterized using Biolog FF Microplates. It was found that soil properties, especially soil organic carbon and water content, contributed significantly to the variations in soil microbes. With increasing soil depth, the soil microbial biomass, fungal biomass, and fungal catabolic ability diminished; however, the ratio of fungi to bacteria increased. The fungal ratio was higher under larch forests compared to that under poplar, birch, and their mixed forests, although the soil microbial biomass was lower. The direct contribution of vegetation types to the soil microbial community variation was 12%. If the indirect contribution through soil organic carbon was included, variations in the vegetation type had substantial influences on soil microbial composition and diversity.

  14. Evaluation of the Contamination by Explosives and Metals in Soils, Vegetation, Surface Water and Sediment at Cold Lake Air Weapons Range (CLAWR), Alberta, Phase 2

    DTIC Science & Technology

    2004-10-01

    Shaver River. La stratégie d’échantillonnage par section transversale linéaire a été appliquée aux sites Alpha et Jimmy Lake. Dans Shaver River, une... Programmes on site characterization allowed the development of a unique expertise and positioned our departments to better understand the impacts of...characterized within the Programme were mainly army bases such as CFB Chilliwack, Shilo, Valcartier, Gagetown in Canada and, Fort Bliss, Fort Lewis, Yakima

  15. A method to downscale soil moisture to fine resolutions using topographic, vegetation, and soil data

    NASA Astrophysics Data System (ADS)

    Ranney, Kayla J.; Niemann, Jeffrey D.; Lehman, Brandon M.; Green, Timothy R.; Jones, Andrew S.

    2015-02-01

    Soil moisture can be estimated over large regions with spatial resolutions greater than 500 m, but many applications require finer resolutions (10-100 m). Several methods use topographic data to downscale, but vegetation and soil patterns can also be important. In this paper, a downscaling model that uses fine-resolution topographic, vegetation, and soil data is presented. The method is tested at the Cache la Poudre catchment where detailed vegetation and soil data were collected. Additional testing is performed at the Tarrawarra and Nerrigundah catchments where limited soil data are available. Downscaled soil moisture patterns at Cache la Poudre improve when vegetation and soil data are used, and model performance is similar to an EOF method. Using interpolated soil data at Tarrawarra and Nerrigundah decreases model performance and results in worse performance than an EOF method, suggesting that soil data needs greater spatial detail and accuracy to be useful for downscaling.

  16. Characteristics of nitrogen balance in open-air and greenhouse vegetable cropping systems of China.

    PubMed

    Ti, Chaopu; Luo, Yongxia; Yan, Xiaoyuan

    2015-12-01

    Nitrogen (N) loss from vegetable cropping systems has become a significant environmental issue in China. In this study, estimation of N balances in both open-air and greenhouse vegetable cropping systems in China was established. Results showed that the total N input in open-air and greenhouse vegetable cropping systems in 2010 was 5.44 and 2.60 Tg, respectively. Chemical fertilizer N input in the two cropping systems was 201 kg N ha(-1) per season (open-air) and 478 kg N ha(-1) per season (greenhouse). The N use efficiency (NUE) was 25.9 ± 13.3 and 19.7 ± 9.4% for open-air and greenhouse vegetable cropping systems, respectively, significantly lower than that of maize, wheat, and rice. Approximately 30.6% of total N input was accumulated in soils and 0.8% was lost by ammonia volatilization in greenhouse vegetable system, while N accumulation and ammonia volatilization accounted for 19.1 and 11.1%, respectively, of total N input in open-air vegetable systems.

  17. Evaluation of Landsat Thematic Mapper for vegetated alluvium soils information

    NASA Technical Reports Server (NTRS)

    Thompson, D. R.; Henderson, K. E.; Houston, A. G.; Pitts, D. E.

    1983-01-01

    Landsat Thematic Mapper data acquired over Mississippi County, Arkansas, on August 22, 1982, were evaluated whether TM provides information that could be used for soil association maps and if soil properties (variability within vegetated fields) can be detected with the new bands on TM. It was found that TM data - especially the mid-IR and thermal bands - show the capability for separating vegetated soil landscapes on a broad basis. Analysis at the field level with a crop growing indicates that TM, with its additional and narrower bands and improved spatial resolution is influenced by within-field variability due to soils.

  18. Using Vegetation Maps to Provide Information on Soil Distribution

    NASA Astrophysics Data System (ADS)

    José Ibáñez, Juan; Pérez-Gómez, Rufino; Brevik, Eric C.; Cerdà, Artemi

    2016-04-01

    Many different types of maps (geology, hydrology, soil, vegetation, etc.) are created to inventory natural resources. Each of these resources is mapped using a unique set of criteria, including scales and taxonomies. Past research has indicated that comparing the results of different but related maps (e.g., soil and geology maps) may aid in identifying deficiencies in those maps. Therefore, this study was undertaken in the Almería Province (Andalusia, Spain) to (i) compare the underlying map structures of soil and vegetation maps and (ii) to investigate if a vegetation map can provide useful soil information that was not shown on a soil map. To accomplish this soil and vegetation maps were imported into ArcGIS 10.1 for spatial analysis. Results of the spatial analysis were exported to Microsoft Excel worksheets for statistical analyses to evaluate fits to linear and power law regression models. Vegetative units were grouped according to the driving forces that determined their presence or absence (P/A): (i) climatophilous (climate is the only determinant of P/A) (ii); lithologic-climate (climate and parent material determine PNV P/A); and (iii) edaphophylous (soil features determine PNV P/A). The rank abundance plots for both the soil and vegetation maps conformed to Willis or Hollow Curves, meaning the underlying structures of both maps were the same. Edaphophylous map units, which represent 58.5% of the vegetation units in the study area, did not show a good correlation with the soil map. Further investigation revealed that 87% of the edaphohygrophylous units (which demand more soil water than is supplied by other soil types in the surrounding landscape) were found in ramblas, ephemeral riverbeds that are not typically classified and mapped as soils in modern systems, even though they meet the definition of soil given by the most commonly used and most modern soil taxonomic systems. Furthermore, these edaphophylous map units tend to be islands of biodiversity

  19. INTERCOMPARISON OF ALTERNATIVE VEGETATION DATABASES FOR REGIONAL AIR QUALITY MODELING

    EPA Science Inventory

    Vegetation cover data are used to characterize several regional air quality modeling processes, including the calculation of heat, moisture, and momentum fluxes with the Mesoscale Meteorological Model (MM5) and the estimate of biogenic volatile organic compound and nitric oxide...

  20. Measurement of soil hydraulic conductivity in relation with vegetation

    NASA Astrophysics Data System (ADS)

    Chen, Xi; Cheng, Qinbo

    2010-05-01

    Hydraulic conductivity is a key parameter which influences hydrological processes of infiltration, surface and subsurface runoff. Vegetation alters surface characteristics (e.g., surface roughness, litter absorption) or subsurface characteristics (e.g. hydraulic conductivity). Field infiltration experiment of a single ring permeameter is widely used for measuring soil hydraulic conductivity. Measurement equipment is a simple single-ring falling head permeameter which consists of a hollow cylinder that is simply inserted into the top soil. An optimization method on the basis of objective of minimum error between the measured and simulated water depths in the single-ring is developed for determination of the soil hydraulic parameters. Using the single ring permeameter, we measured saturated hydraulic conductivities (Ks) of the red loam soil with and without vegetation covers on five hillslopes at Taoyuan Agro-Ecology Experimental Station, Hunan Province of China. For the measurement plots without vegetation roots, Ks value of the soil at 25cm depth is much smaller than that of surface soil (1.52×10-4 vs. 1.10×10-5 m/s). For the measurement plots with vegetation cover, plant roots significantly increase Ks of the lower layer soil but this increase is not significant for the shallow soil. Moreover, influences of vegetation root on Ks depend on vegetation species and ages. Ks value of the Camellia is about three times larger than that of seeding of Camphor (2.62×10-4 vs. 9.82×10-5 m/s). Ks value of the matured Camellia is 2.72×10-4 m/s while Ks value of the young Camellia is only 2.17×10-4 m/s. Key words: single ring permeameter; soil hydraulic conductivity; vegetation

  1. [Soil moisture estimation model based on multiple vegetation index].

    PubMed

    Wu, Hai-long; Yu, Xin-xiao; Zhang, Zhen-ming; Zhang, Yan

    2014-06-01

    Estimating soil moisture conveniently and exactly is a hot issues in water resource monitoring among agriculture and forestry. Estimating soil moisture based on vegetation index has been recognized and applied widely. 8 vegetation indexes were figured out based on the hyper-spectral data measured by portable spectrometer. The higher correlation indexes among 8 vegetation indexes and surface vegetation temperature were selected by Gray Relative Analysis method (GRA). Then, these selected indexes were analyzed using Multiple Linear Regression to establish soil moisture estimation model based on multiple vegetation indexes, and the model accuracy was evaluated. The accuracy evaluation indicated that the fitting was satisfied and the significance was 0.000 (P < 0.001). High correlation was turned out between estimated and measured soil moisture with R2 reached 0.636 1 and RMSE 2.149 9. This method introduced multiple vegetation indexes into soil water content estimating over micro scale by non-contact measuring method using portable spectrometer. The exact estimation could be an appropriate replacement for remote sensing inversion and direct measurement. The model could estimate soil moisture quickly and accurately, and provide theory and technology reference for water resource management in agriculture and forestry.

  2. Soil, water, and vegetation conditions in south Texas

    NASA Technical Reports Server (NTRS)

    Wiegand, C. L.; Gausman, H. W.; Leamer, R. W.; Richardson, A. J.; Everitt, J. H.; Gerbermann, A. H. (Principal Investigator)

    1977-01-01

    The author has identified the following significant results. The best wavelengths in the 0.4 to 2.5 micron interval were determined for detecting lead toxicity and ozone damage, distinguishing succulent from woody species, and detecting silverleaf sunflower. A perpendicular vegetation index, a measure of the distance from the soil background line, in MSS 5 and MSS 7 data space, of pixels containing vegetation was developed and tested as an indicator of vegetation development and crop vigor. A table lookup procedure was devised that permits rapid identification of soil background and green biomass or phenological development in LANDSAT scenes without the need for training data.

  3. Importance of Soil Texture in Paleo-Vegetation Modeling Studies

    NASA Astrophysics Data System (ADS)

    Shellito, C. J.; Clifthorne, S.; Sloan, L. C.; Kueppers, L.

    2005-12-01

    The utility of a dynamic global vegetation model (DGVM) depends on the accuracy of the background climatology driving the model and the boundary conditions. In this study, we examine the sensitivity of the NCAR LSM-DGVM to one aspect of the boundary condition, the global soil texture. Soil texture is a critical factor influencing the availability of soil moisture. Available soil moisture will generally determine the dominant vegetation in a region, and, both soil moisture and vegetation will have important feedbacks on climate. Most paleoclimate modeling studies incorporate a globally uniform soil texture due to a lack of a global datasets regarding paleosol types. This becomes problematic when trying to address questions regarding potential changes in the global ecosystem due to a change in climate because the influence of soil texture on equilibrium vegetation in a DGVM experiment may be as large as other climatic forcing factors in a given region. In this study, we consider the effect of soil texture on the distribution of global vegetation in an Early Eocene DGVM study. We generate a global distribution of clay abundances using annual averaged temperatures and precipitation estimates from previous Eocene modeling studies. In all previous Eocene climate modeling studies, clay is specified at globally uniform value of 18%. In our new Eocene soil distribution, clay percentages vary from near zero to 80%. We incorporate the new soil scheme into the surface boundary conditions for a DGVM experiment. As model output demonstrates, the clay has a pronounced impact on soil moisture, which has a strong impact on the presence and abundance of plant functional types in the model.

  4. Vegetation management with fire modifies peatland soil thermal regime.

    PubMed

    Brown, Lee E; Palmer, Sheila M; Johnston, Kerrylyn; Holden, Joseph

    2015-05-01

    Vegetation removal with fire can alter the thermal regime of the land surface, leading to significant changes in biogeochemistry (e.g. carbon cycling) and soil hydrology. In the UK, large expanses of carbon-rich upland environments are managed to encourage increased abundance of red grouse (Lagopus lagopus scotica) by rotational burning of shrub vegetation. To date, though, there has not been any consideration of whether prescribed vegetation burning on peatlands modifies the thermal regime of the soil mass in the years after fire. In this study thermal regime was monitored across 12 burned peatland soil plots over an 18-month period, with the aim of (i) quantifying thermal dynamics between burned plots of different ages (from <2 to 15 + years post burning), and (ii) developing statistical models to determine the magnitude of thermal change caused by vegetation management. Compared to plots burned 15 + years previously, plots recently burned (<2-4 years) showed higher mean, maximum and range of soil temperatures, and lower minima. Statistical models (generalised least square regression) were developed to predict daily mean and maximum soil temperature in plots burned 15 + years prior to the study. These models were then applied to predict temperatures of plots burned 2, 4 and 7 years previously, with significant deviations from predicted temperatures illustrating the magnitude of burn management effects. Temperatures measured in soil plots burned <2 years previously showed significant statistical disturbances from model predictions, reaching +6.2 °C for daily mean temperatures and +19.6 °C for daily maxima. Soil temperatures in plots burnt 7 years previously were most similar to plots burned 15 + years ago indicating the potential for soil temperatures to recover as vegetation regrows. Our findings that prescribed peatland vegetation burning alters soil thermal regime should provide an impetus for further research to understand the consequences of thermal regime

  5. Differentiating elements of the soil-vegetation complex

    NASA Technical Reports Server (NTRS)

    Baumgardner, M. F.

    1972-01-01

    The application of remote sensing to study soil-vegetation systems requires quantification and precise location of ground observation data such that they can be correlated with multispectral aerial acquired data. Griddling and sampling of an area for exact identification in a known address on magnetic tape containing multispectral scanner data produces quantitative physico-chemical parameters and the energy which is radiating from within the soil-vegetation complex of an area. Example classifications and spectral mappings of soils made from multispectral scanner data are included.

  6. Linking soil biodiversity and vegetation: implications for a changing planet.

    PubMed

    Sylvain, Zachary A; Wall, Diana H

    2011-03-01

    Soil biota are intimately tied to plant communities through herbivory and symbiosis and indirectly by the decomposition of dead organic plant material. Through both roots and aboveground organic material (e.g., leaves and wood), plants provide substantial inputs of organic matter to soil systems. Plants are the basis for most biotic soil food webs that comprise an enormous diversity of species whose multiple interactions function to help regulate nutrient cycling, which in turn influences plant growth. Many factors govern the biogeography of soil biota, including the physical and chemical properties of soil, climate, the composition and type of vegetation, and interactions with other soil biota. Despite awareness of factors influencing soil communities, no single factor allows predictions of soil animal diversity or distribution. However, research is showing that plants can have unique soil biotic communities. Degradation of soil, which removes predators and biotic regulation that occurs in less managed ecosystems, can result in increased pathogens and pests that affect humans, other animals and plants. Global changes such as land use, desertification, and soil pollution all have been shown to alter soil animal diversity and abundance. Because of our dependence on soils and plant production, studies linking soil biotic communities to primary productivity are needed to assure long-term soil sustainability.

  7. The role of vegetation in mitigating air quality impacts from ...

    EPA Pesticide Factsheets

    On Apri1 27-28, 2019, a multi-disciplinary group of researchers and po1icymakers met to discuss the state-of-the-science regarding the potential of roadside vegetation to mitigate near-road air quality impacts. Concerns over population exposures to traffic-generated pollutants near roads have grown with an increasing number of health studies reporting links between proximity to roads and adverse health effects. A recent EM article described how roadway design, including the presence of roadside vegetation, may be a means of mitigating air pollutant concentrations near roads. As a first step in evaluating this concept, representatives from government agencies, academia, state and local agencies, and non-governmental environmental organizations with expertise in air quality, urban forestry, ecosystem services, and environmental policy reviewed the current science and identified future activities in evaluating the potential role of vegetation in mitigating near-road air pollutant concentrations. journal article

  8. Chemical-specific representation of air--soil exchange and soil penetration in regional multimedia models.

    PubMed

    McKone, T E; Bennett, D H

    2003-07-15

    In multimedia mass-balance models, the soil compartment is an important sink as well as a conduit for transfers to vegetation and shallow groundwater. Here a novel approach for constructing soil transport algorithms for multimedia fate models is developed and evaluated. The resulting algorithms account for diffusion in gas and liquid components; advection in gas, liquid, or solid phases; and multiple transformation processes. They also provide an explicit quantification of the characteristic soil penetration depth. We construct a compartment model using three and four soil layers to replicate with high reliability the flux and mass distribution obtained from the exact analytical solution describing the transient dispersion, advection, and transformation of chemicals in soil layers with different properties but a fixed boundary condition at the air-soil surface. The soil compartment algorithms can be dynamically linked to other compartments (air, vegetation, groundwater, surface water) in multimedia fate models. We demonstrate and evaluate the performance of the algorithms in a model with applications to benzene, benzo[a]pyrene, MTBE, TCDD, and tritium.

  9. CAOS: the nested catchment soil-vegetation-atmosphere observation platform

    NASA Astrophysics Data System (ADS)

    Weiler, Markus; Blume, Theresa

    2016-04-01

    Most catchment based observations linking hydrometeorology, ecohydrology, soil hydrology and hydrogeology are typically not integrated with each other and lack a consistent and appropriate spatial-temporal resolution. Within the research network CAOS (Catchments As Organized Systems), we have initiated and developed a novel and integrated observation platform in several catchments in Luxembourg. In 20 nested catchments covering three distinct geologies the subscale processes at the bedrock-soil-vegetation-atmosphere interface are being monitored at 46 sensor cluster locations. Each sensor cluster is designed to observe a variety of different fluxes and state variables above and below ground, in the saturated and unsaturated zone. The numbers of sensors are chosen to capture the spatial variability as well the average dynamics. At each of these sensor clusters three soil moisture profiles with sensors at different depths, four soil temperature profiles as well as matric potential, air temperature, relative humidity, global radiation, rainfall/throughfall, sapflow and shallow groundwater and stream water levels are measured continuously. In addition, most sensors also measure temperature (water, soil, atmosphere) and electrical conductivity. This setup allows us to determine the local water and energy balance at each of these sites. The discharge gauging sites in the nested catchments are also equipped with automatic water samplers to monitor water quality and water stable isotopes continuously. Furthermore, water temperature and electrical conductivity observations are extended to over 120 locations distributed across the entire stream network to capture the energy exchange between the groundwater, stream water and atmosphere. The measurements at the sensor clusters are complemented by hydrometeorological observations (rain radar, network of distrometers and dense network of precipitation gauges) and linked with high resolution meteorological models. In this

  10. Mediterranean shrub vegetation: soil protection vs. water availability

    NASA Astrophysics Data System (ADS)

    García Estringana, Pablo; Nieves Alonso-Blázquez, M.; Alegre, Alegre; Cerdà, Artemi

    2014-05-01

    Soil Erosion and Land Degradation are closely related to the changes in the vegetation cover (Zhao et al., 2013). Although other factors such as rainfall intensiy or slope (Ziadat and Taimeh, 2013) the plant covers is the main factor that controls the soil erosion (Haregeweyn, 2013). Plant cover is the main factor of soil erosion processes as the vegetation control the infiltration and runoff generation (Cerdà, 1998a; Kargar Chigani et al., 2012). Vegetation cover acts in a complex way in influencing on the one hand on runoff and soil loss and on the other hand on the amount and the way that rainfall reaches the soil surface. In arid and semiarid regions, where erosion is one of the main degradation processes and water is a scant resource, a minimum percentage of vegetation coverage is necessary to protect the soil from erosion, but without compromising the availability of water (Belmonte Serrato and Romero Diaz, 1998). This is mainly controlled by the vegetation distribution (Cerdà, 1997a; Cammeraat et al., 2010; Kakembo et al., 2012). Land abandonment is common in Mediterranean region under extensive land use (Cerdà, 1997b; García-Ruiz, 2010). Abandoned lands typically have a rolling landscape with steep slopes, and are dominated by herbaceous communities that grow on pasture land interspersed by shrubs. Land abandonment use to trigger an increase in soil erosion, but the vegetation recovery reduces the impact of the vegetation. The goal of this work is to assess the effects of different Mediterranean shrub species (Dorycnium pentaphyllum Scop., Medicago strasseri, Colutea arborescens L., Retama sphaerocarpa, L., Pistacia Lentiscus L. and Quercus coccifera L.) on soil protection (runoff and soil losses) and on rainfall reaching soil surface (rainfall partitioning fluxes). To characterize the effects of shrub vegetation and to evaluate their effects on soil protection, two field experiments were carried out. The presence of shrub vegetation reduced runoff by

  11. Vegetation fires and air pollution in Vietnam.

    PubMed

    Le, Thanh Ha; Thanh Nguyen, Thi Nhat; Lasko, Kristofer; Ilavajhala, Shriram; Vadrevu, Krishna Prasad; Justice, Chris

    2014-12-01

    Forest fires are a significant source of air pollution in Asia. In this study, we integrate satellite remote sensing data and ground-based measurements to infer fire-air pollution relationships in selected regions of Vietnam. We first characterized the active fires and burnt areas at a regional scale from MODIS satellite data. We then used satellite-derived active fire data to correlate the resulting atmospheric pollution. Further, we analyzed the relationship between satellite atmospheric variables and ground-based air pollutant parameters. Our results show peak fire activity during March in Vietnam, with hotspots in the Northwest and Central Highlands. Active fires were significantly correlated with UV Aerosol Index (UVAI), aerosol extinction absorption optical depth (AAOD), and Carbon Monoxide. The use of satellite aerosol optical thickness improved the prediction of Particulate Matter (PM) concentration significantly.

  12. Soil moisture and vegetation memories in a cold, arid climate

    NASA Astrophysics Data System (ADS)

    Shinoda, Masato; Nandintsetseg, Banzragch

    2011-10-01

    Continental climate is established as a result of a complex interplay between the atmosphere and various land-surface systems such as the biosphere, soil, hydrosphere, and cryosphere. These systems function as climate memory, allowing the maintenance of interannual atmospheric anomalies. In this paper, we present new observational evidence of an interseasonal moisture memory mechanism mediated by the land surface that is manifested in the coupled cold and arid climate of Mongolia. Interannual anomalies of soil moisture and vegetation due to rainfall during a given summer are maintained through the freezing winter months to the spring, acting as an initial condition for subsequent summer land-surface and rainfall conditions. Both the soil moisture and vegetation memories were prominent over the eastern part of the Mongolian steppe zone (103-112°E and 46-50°N). That is, the cold-season climate with low evapotranspiration and strong soil freezing acts to prolong the decay time scale of autumn soil moisture anomalies to 8.2 months that is among the longest in the world. The vegetation also has a memory of the similar time scale, likely because the large rootstock of the perennial plants dominant in the Mongolian steppe may remain alive, retain belowground biomass anomalies during the winter, and have an impact on the initial vegetation growth during the spring.

  13. Assessment of regional biomass-soil relationships using vegetation indexes

    NASA Technical Reports Server (NTRS)

    Lozano-Garcia, D. Fabian; Fernandez, R. Norberto; Johannsen, Chris J.

    1991-01-01

    The development of photosynthetic active biomass in different ecological conditions, as indicated by normalized difference vegetation indices (NDVIs) is compared by performing a stratified sampling (based on soil assocations) on data acquired over Indiana. Data from the NOAA-10 AVHRR were collected for the 1987 and 1988 growing seasons. An NDVI transformation was performed using the two optical bands of the sensor (0.58-0.68 microns and 0.72-1.10 microns). The NDVI is related to the amount of active photosynthetic biomass present on the ground. Samples of NDVI values over 45 fields representing eight soil associations throughout Indiana were collected to assess the effect of soil conditions and acquisition date on the spectral response of the vegetation, as shown by the NDVIs. Statistical analysis of results indicate that land-cover types (forest, forest/pasture, and crops), soil texture, and soil water-holding capacity have an important effect on vegetation biomass changes as measured by AVHRR data. Acquisition dates should be selected with condideration of the phenological stages of vegetation. Sampling of AVHRR data over extended areas should be stratified according to physiographic units rather than man-made boundaries. This will provide more homogeneous samples for statistical analysis.

  14. Antibiotic uptake by vegetable crops from manure-applied soils.

    PubMed

    Kang, Dong Hee; Gupta, Satish; Rosen, Carl; Fritz, Vincent; Singh, Ashok; Chander, Yogesh; Murray, Helene; Rohwer, Charlie

    2013-10-23

    This study quantified the uptake of five antibiotics (chlortetracycline, monensin, sulfamethazine, tylosin, and virginiamycin) by 11 vegetable crops in two different soils that were fertilized with raw versus composted turkey and hog manures or inorganic fertilizer. Almost all vegetables showed some uptake of antibiotics from manure treatments. However, statistical testing showed that except for a few isolated treatments the concentrations of all antibiotics in vegetable tissues were generally less than the limits of quantification. Further testing of the significant treatments showed that antibiotic concentrations in vegetables from many of these treatments were not significantly different than the corresponding concentrations from the fertilizer treatment (matrix effect). All five antibiotic concentrations in the studied vegetables were <10 μg kg(-1). On the basis of the standards for maximum residue levels in animal tissues and suggested maximum daily intake based on body weight, this concentration would not pose any health risk unless one is allergic to that particular antibiotic.

  15. Feedbacks between vegetation and soil moisture in mountain grasslands

    NASA Astrophysics Data System (ADS)

    Castelli, M.; Bertoldi, G.; Notarnicola, C.; Brenner, J.; Greifeneder, F.; Niedrist, G.; Tappeiner, U.

    2015-12-01

    Soil moisture content (SMC) is a key variable for water budget and controls both physical processes, as runoff generation, and biological processes, as vegetation development. On the other hand, vegetation and land management influence soil evolution and therefore SMC dynamic. Moreover, in mountain areas complex topography adds an additional control on water fluxes and climate. For those reasons, understanding the controls on the spatio-temporal variability of SMC is essential to predict how perturbations in vegetation and climate affects mountain hydrology. In this contribution we want to analyze the impact of different land management (meadows versus pastures) on the spatial and temporal dynamic of surface and root-zone SMC, and its relationships with climate and topography. We focus on water-limited alpine grasslands in the LTER area Mazia Valley in the European Alps. The infrastructure includes a dense network of more than 20 stations measuring soil moisture, biomass production observations and two eddy-covariance stations over meadow and pasture. Moreover, more than ten high-resolution SAR (Sentinel1 and RADARSAT2) images were acquired, in combination with ground surveys to monitor SMC spatial distribution. In order to understand the different physical controls, SMC has been also modelled using the GEOtop hydrological model, coupled with a dynamic vegetation model. Results show that meadows and pastures have different behaviors. Meadows are in general wetter and in flatter locations. This leads to higher vegetation productivity, development of soils with higher water holding capacity and to a positive feedback on SMC. In contrast, pastures are drier, in steeper locations with lower vegetation density and more compact soils due animal trampling, with a negative feedback on SMC. This co-evolution of land cover and SMC leads to persistent spatial patterns controlled by both topography and management.

  16. Soil Moisture Prediction in the Soil, Vegetation and Snow (SVS) Scheme

    NASA Astrophysics Data System (ADS)

    Alavi, Nasim; Bélair, Stéphane; Fortin, Vincent; Zhang, Shunli; Husain, Syed; Carrera, Marco; Abrahamowicz, Maria

    2016-04-01

    A new land surface scheme has been developed at Environment of Canada to provide surface fluxes of momentum, heat and moisture for the Global Environmental Multiscale (GEM) atmospheric model. In this study, the performance of the soil, vegetation and snow (SVS) scheme in estimating surface and root-zone soil moisture is evaluated against the ISBA (Interactions between Surface, Biosphere, and Atmosphere) scheme currently used operationally within GEM for numerical weather prediction. In addition, the sensitivity of SVS soil moisture results to soil texture and vegetation data sources (type and fractional coverage) has been explored. The performance of SVS and ISBA was assessed against a large set of in situ as well as brightness temperature data from the Soil Moisture and Ocean Salinity (SMOS) satellite over North America. The results indicate that SVS estimates the time evolution of soil moisture more accurately, and compared to ISBA results in higher correlations with observations and reduced errors. The sensitivity tests carried out during this study revealed that SVS soil moisture results are not affected significantly by the soil texture data from different sources. The vegetation data source, however, has a major impact on the soil moisture results predicted by SVS, and accurate specification of vegetation characteristics is crucial for accurate soil moisture prediction.

  17. Aminopyralid soil residues affect rotational vegetable crops in Florida

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field experiments were conducted to determine the sensitivity of bell pepper, eggplant, tomato, muskmelon, and watermelon to aminopyralid soil residues. Aminopyralid was applied at six rates ranging from 0.0014 kg ae ha 1 to 0.0448 kg ae ha 1, and vegetable crops were planted in the treated areas. ...

  18. Organochlorine pesticides in air and soil and estimated air-soil exchange in Punjab, Pakistan.

    PubMed

    Syed, Jabir Hussain; Malik, Riffat Naseem; Liu, Di; Xu, Yue; Wang, Yan; Li, Jun; Zhang, Gan; Jones, Kevin C

    2013-02-01

    This study provides the first systematic data on the distribution of organochlorine pesticides (OCPs) in the soils and atmosphere of the Punjab province, Pakistan. Atmospheric concentrations of OCPs were estimated by using the polyurethane foam passive air sampling (PUF-PAS) technique. DDTs (dichlorodiphenyltrichloroethane), HCHs (hexachlorocyclohexane) and chlordane were the dominant OCPs found in both soil and air samples. The average concentrations of DDTs, HCHs and chlordane were 350, 55 and 99 pg m(-3) in air and 40, 7.8 and 3.8 ng g(-1) in soils, respectively. Air-soil exchange of OCPs was estimated by calculating the fugacities in soil and air. Fugacity fraction (ff) values indicate that soils are acting as a secondary source to contaminate the atmosphere at certain sampling stations.

  19. Investigation of soil influences in AVHRR red and near-infrared vegetation index imagery

    NASA Technical Reports Server (NTRS)

    Huete, A. R.; Tucker, C. J.

    1991-01-01

    The effects of soil optical properties on vegetation index imagery are analyzed with ground-based spectral measurements and both simulated and actual AVHRR data from the NOAA satellites. Soil effects on vegetation indices were divided into primary variations associated with the brightness of bare soils, secondary variations attributed to 'color' differences among bare soils, and soil-vegetation spectral mixing. Primary variations were attributed to shifts in the soil line owing to atmosphere or soil composition. Secondary soil variance was responsible for the Saharan desert 'artefact' areas of increased vegetation index response in AVHRR imagery.

  20. Reflectance of vegetation, soil, and water

    NASA Technical Reports Server (NTRS)

    Wiegand, C. L. (Principal Investigator); Gausman, H. W.; Leamer, R. W.; Richardson, A. J.; Gerbermann, A. H.; Torline, R. J.; Gautreaux, M. R.; Everitt, J. H.; Guellar, J. A.; Rodriguez, R. R.

    1974-01-01

    The author has identified the following significant results. Bands 4, 5, and 7 and 5, 6, and 7 were best for distinguishing among crop and soil categories in ERTS-1 SCENES 1182-16322 (1-21-73) and 1308-16323 (5-21-73) respectively. Chlorotic sorghum areas 2.8 acres or larger in size were identified on a computer printout of band 5 data. Reflectance of crop residues was more often different from bare soil in band 4 than in bands 5, 6, and 7. Simultaneously acquired aircraft and spacecraft MSS data indicated that spacecraft surveys are as reliable as aircraft surveys. ERTS-1 data were successfully used to estimate acreage of citrus, cotton, and sorghum as well as idle crop land.

  1. Calculations of radar backscattering coefficient of vegetation-covered soils

    NASA Technical Reports Server (NTRS)

    Mo, T.; Schmugge, T. J.; Jackson, T. J. (Principal Investigator)

    1983-01-01

    A model for simulating the measured backscattering coefficient of vegetation-covered soil surfaces includes both coherent and incoherent components of the backscattered radar pulses from a rough sil surface. The effect of vegetation canopy scattering is also incorporated into the model by making the radar pulse subject to two-way attenuation and volume scattering when it passes through the vegetation layer. Model results agree well with the measured angular distributions of the radar backscattering coefficient for HH polarization at the 1.6 GHz and 4.75 GHz frequencies over grass-covered fields. It was found that the coherent scattering component is very important at angles near nadir, while the vegetation volume scattering is dominant at incident angles 30 degrees.

  2. Variation in Soil Respiration across Soil and Vegetation Types in an Alpine Valley

    PubMed Central

    Rubin, Aurélie

    2016-01-01

    Background and Aims Soils of mountain regions and their associated plant communities are highly diverse over short spatial scales due to the heterogeneity of geological substrates and highly dynamic geomorphic processes. The consequences of this heterogeneity for biogeochemical transfers, however, remain poorly documented. The objective of this study was to quantify the variability of soil-surface carbon dioxide efflux, known as soil respiration (Rs), across soil and vegetation types in an Alpine valley. To this aim, we measured Rs rates during the peak and late growing season (July-October) in 48 plots located in pastoral areas of a small valley of the Swiss Alps. Findings Four herbaceous vegetation types were identified, three corresponding to different stages of primary succession (Petasition paradoxi in pioneer conditions, Seslerion in more advanced stages and Poion alpinae replacing the climactic forests), as well as one (Rumicion alpinae) corresponding to eutrophic grasslands in intensively grazed areas. Soils were developed on calcareous alluvial and colluvial fan deposits and were classified into six types including three Fluvisols grades and three Cambisols grades. Plant and soil types had a high level of co-occurrence. The strongest predictor of Rs was soil temperature, yet we detected additional explanatory power of sampling month, showing that temporal variation was not entirely reducible to variations in temperature. Vegetation and soil types were also major determinants of Rs. During the warmest month (August), Rs rates varied by over a factor three between soil and vegetation types, ranging from 2.5 μmol m-2 s-1 in pioneer environments (Petasition on Very Young Fluvisols) to 8.5 μmol m-2 s-1 in differentiated soils supporting nitrophilous species (Rumicion on Calcaric Cambisols). Conclusions Overall, this study provides quantitative estimates of spatial and temporal variability in Rs in the mountain environment, and demonstrates that estimations of

  3. Organic fertilization for soil improvement in a vegetable cropping system

    NASA Astrophysics Data System (ADS)

    Verhaeghe, Micheline; De Rocker, Erwin; De Reycke, Luc

    2016-04-01

    Vegetable Research Centre East-Flanders Karreweg 6, 9770 Kruishoutem, Belgium A long term trial for soil improvement by organic fertilization was carried out in Kruishoutem from 2001 till 2010 in a vegetable rotation (carrots - leek - lettuce (2/year) - cauliflower (2/year) - leek - carrots - lettuce (2/year) - cauliflower (2/year) - leek and spinach). The trial compared yearly applications of 30 m²/ha of three types of compost (green compost, vfg-compost and spent mushroom compost) with an untreated object which did not receive any organic fertilization during the trial timescale. The organic fertilization was applied shortly before the cropping season. Looking at the soil quality, effects of organic fertilization manifest rather slow. The first four years after the beginning of the trial, no increase in carbon content of the soil is detectable yet. Although, mineralization of the soil has increased. The effect on the mineralization is mainly visible in crops with a lower N uptake (e.g. carrots) leading to a higher nitrate residue after harvest. Effects on soil structure and compaction occur rather slowly although, during the first two cropping seasons compost applications increase the water retention capacity of the soil. Compost increases the pH of the soil from the first year on till the end of the trial in 2010. Thus, organic fertilization impedes acidification in light sandy soils. Also soil fertility benefits from compost by an increase in K-, Ca- and Mg- content in the soil from the second year on. After 10 years of organic fertilization, yield and quality of spinach were increased significantly (p<0.05) compared to the untreated object. Also leek (2002 and 2009) and lettuce (2003 and 2007) benefit from organic fertilization.

  4. Carbon Dynamics in Vegetation and Soils

    NASA Technical Reports Server (NTRS)

    Trumbore, Susan; Chambers, Jeffrey Q.; Camargo, Plinio; Martinelli, Luiz; Santos, Joaquim

    2005-01-01

    The overall goals of CD-08 team in Phase I were to quantify the contributions of different components of the carbon cycle to overall ecosystem carbon balance in Amazonian tropical forests and to undertake process studies at a number of sites along the eastern LBA transect to understand how and why these fluxes vary with site, season, and year. We divided this work into a number of specific tasks: (1) determining the average rate (and variability) of tree growth over the past 3 decades; (2) determining age demographics of tree populations, using radiocarbon to determine tree age; (3) assessing the rate of production and decomposition of dead wood debris; (4) determining turnover rates for organic matter in soils and the mean age of C respired from soil using radiocarbon measurements; and (5) comparing our results with models and constructing models to predict the potential of tropical forests to function as sources or sinks of C. This report summarizes the considerable progress made towards our original goals, which have led to increased understanding of the potential for central Amazon forests to act as sources or sinks of carbon with altered productivity. The overall picture of tropical forest C dynamics emerging from our Phase I studies suggests that the fraction of gross primary production allocated to growth in these forests is only 25-30%, as opposed to the 50% assumed by many ecosystem models. Consequent slow tree growth rates mean greater mean tree age for a given diameter, as reflected in our measurements and models of tree age. Radiocarbon measurements in leaf and root litter suggest that carbon stays in living tree biomass for several years up to a decade before being added to soils, where decomposition is rapid. The time lags predicted from 14C, when coupled with climate variation on similar time scales, can lead to significant interannual variation in net ecosystem C exchange.

  5. Reflectance of vegetation, soil, and water

    NASA Technical Reports Server (NTRS)

    Wiegand, C. L. (Principal Investigator)

    1973-01-01

    There are no author-identified significant results in this report. This report deals with the selection of the best channels from the 24-channel aircraft data to represent crop and soil conditions. A three-step procedure has been developed that involves using univariate statistics and an F-ratio test to indicate the best 14 channels. From the 14, the 10 best channels are selected by a multivariate stochastic process. The third step involves the pattern recognition procedures developed in the data analysis plan. Indications are that the procedures in use are satsifactory and will extract the desired information from the data.

  6. Soil air CO2 concentration as an integrative parameter of soil structure

    NASA Astrophysics Data System (ADS)

    Ebeling, Corinna; Gaertig, Thorsten; Fründ, Heinz-Christian

    2015-04-01

    The assessment of soil structure is an important but difficult issue and normally takes place in the laboratory. Typical parameters are soil bulk density, porosity, water or air conductivity or gas diffusivity. All methods are time-consuming. The integrative parameter soil air CO2 concentration ([CO2]) can be used to assess soil structure in situ and in a short time. Several studies highlighted that independent of soil respiration, [CO2] in the soil air increases with decreasing soil aeration. Therefore, [CO2] is a useful indicator of soil aeration. Embedded in the German research project RÜWOLA, which focus on soil protection at forest sites, we investigated soil compaction and recovery of soil structure after harvesting. Therefore, we measured soil air CO2 concentrations continuously and in single measurements and compared the results with the measurements of bulk density, porosity and gas diffusivity. Two test areas were investigated: At test area 1 with high natural regeneration potential (clay content approx. 25 % and soil-pH between 5 and 7), solid-state CO2-sensors using NDIR technology were installed in the wheel track of different aged skidding tracks in 5 and 10 cm soil depths. At area 2 (acidic silty loam, soil-pH between 3.5 and 4), CO2-sensors and water-tension sensors (WatermarkR) were installed in 6 cm soil depth. The results show a low variance of [CO2] in the undisturbed soil with a long term mean from May to June 2014 between 0.2 and 0.5 % [CO2] in both areas. In the wheel tracks [CO2] was consistently higher. The long term mean [CO2] in the 8-year-old-wheel track in test area 1 is 5 times higher than in the reference soil and shows a high variation (mean=2.0 %). The 18-year-old wheel track shows a long-term mean of 1.2 % [CO2]. Furthermore, there were strong fluctuations of [CO2] in the wheel tracks corresponding to precipitation and humidity. Similar results were yielded with single measurements during the vegetation period using a portable

  7. On the Opposing Roles of Air Temperature and Wind Speed Variability in Flux Estimation over Partially Vegetated Landscapes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In semi-arid regions the evapotranspiration rates depend on both the spatial distribution of the vegetation and the soil moisture, for a given radiation regime. Remote sensing can provide high resolution spatially distributed estimation of land surface states. However, data on the near surface air p...

  8. A method to downscale soil moisture to fine-resolutions using topographic, vegetation, and soil data

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil moisture can be estimated over large regions with spatial resolutions greater than 500 m, but many applications require finer resolutions (10 – 100 m grid cells). Several methods use topographic data to downscale, but vegetation and soil patterns can also be important. In this paper, a downsc...

  9. [Impact of moss soil crust on vegetation indexes interpretation].

    PubMed

    Fang, Shi-bo; Zhang, Xin-shi

    2011-03-01

    Vegetation indexes were the most common and the most important parameters to characterizing large-scale terrestrial ecosystems. It is vital to get precise vegetation indexes for running land surface process models and computation of NPP change, moisture and heat fluxes over surface. Biological soil crusts (BSC) are widely distributed in arid and semi-arid, polar and sub-polar regions. The spectral characteristics of dry and wet BSCs were quite different, which could produce much higher vegetation indexes value for the wet BSC than for the dry BSC as reported. But no research was reported about whether the BSC would impact on regional vegetation indexes and how much dry and wet BSC had impact on regional vegetation indexes. In the present paper, the most common vegetation index NDVI were used to analyze how the moss soil crusts (MSC) dry and wet changes affect regional NDVI values. It was showed that 100% coverage of the wet MSC have a much higher NDVI value (0.657) than the dry MSC NDVI value (0.320), with increased 0.337. Dry and wet MSC NDVI value reached significant difference between the levels of 0.000. In the study area, MSC, which had the average coverage of 12.25%, would have a great contribution to the composition of vegetation index. Linear mixed model was employed to analyze how the NDVI would change in regional scale as wet MSC become dry MSC inversion. The impact of wet moss crust than the dry moss crust in the study area can make the regional NDVI increasing by 0.04 (14.3%). Due to the MSC existence and rainfall variation in arid and semi-arid zones, it was bound to result in NDVI change instability in a short time in the region. For the wet MSC's spectral reflectance curve is similar to those of the higher plants, misinterpretation of the vegetation dynamics could be more severe due to the "maximum value composite" (MVC) technique used to compose the global vegetation maps in the study of vegetation dynamics. The researches would be useful for

  10. Recommendations for Constructing Roadside Vegetation Barriers to Improve Near-Road Air Quality

    EPA Pesticide Factsheets

    The EPA report, Recommendations for Constructing Roadside Vegetation Barriers to Improve Near-Road Air Quality, summarizes the research findings on the best practices for building roadside vegetative barriers to improve air quality. This fact sheet describ

  11. Biogenic NO emission from a spruce forest soil in the Fichtelgebirge (Germany) under the influence of different understorey vegetation cover

    NASA Astrophysics Data System (ADS)

    Bargsten, A.; Andreae, M. O.; Meixner, F. X.

    2009-04-01

    Within the framework of the EGER project (ExchanGE processes in mountainous Regions) soil samples have been taken from the spruce forest site "Weidenbrunnen" (Fichtelgebirge, Germany) in September 2008 to determine the NO exchange in the laboratory and for a series of soil analyses. The soil was sampled below different understorey vegetation covers: young Norway spruce, moss/litter, blueberries and grass. We investigated the net NO release rate from corresponding organic layers as well as from the A horizon of respective soils. Additionally we measured pH, C/N ratio, contents of ammonium, nitrate, and organic C, bulk density, the thickness of the organic layer and the quality of the organic matter. Net NO release rates (as well as the NO production and NO consumption rates) from the soil samples were determined by a fully automated laboratory incubation & fumigation system. Purified dry air passed five dynamic incubation chambers, four containing water saturated soil samples and one reference chamber. By this procedure, the soil samples dried out slowly (within 2-6 days), covering the full range of soil moisture (0-300% gravimetric soil moisture). To quantify NO production and NO consumption rates separately, soil samples were fumigated with zero-air (approx. 0 ppb NO) and air of 133 ppb NO. The chambers were placed in a thermostatted cabinet for incubation at 10 an 20˚ C. NO and H2O concentrations at the outlet of the five dynamic chambers were measured sequentially by chemiluminescence and IR-absorption based analyzers, switching corresponding valves every two minutes. Net NO release rates were determined from the NO concentration difference between soil containing and reference chambers. Corresponding measurements of H2O mixing ratio yielded the evaporation loss of the soil samples, which (referenced to the gravimetric soil water content before and after the incubation experiment) provided the individual soil moisture contents of each soil samples during the

  12. Chemical-Specific Representation of Air-Soil Exchange and Soil Penetration in Regional Multimedia Models

    SciTech Connect

    McKone, T.E.; Bennett, D.H.

    2002-08-01

    In multimedia mass-balance models, the soil compartment is an important sink as well as a conduit for transfers to vegetation and shallow groundwater. Here a novel approach for constructing soil transport algorithms for multimedia fate models is developed and evaluated. The resulting algorithms account for diffusion in gas and liquid components; advection in gas, liquid, or solid phases; and multiple transformation processes. They also provide an explicit quantification of the characteristic soil penetration depth. We construct a compartment model using three and four soil layers to replicate with high reliability the flux and mass distribution obtained from the exact analytical solution describing the transient dispersion, advection, and transformation of chemicals in soil with fixed properties and boundary conditions. Unlike the analytical solution, which requires fixed boundary conditions, the soil compartment algorithms can be dynamically linked to other compartments (air, vegetation, ground water, surface water) in multimedia fate models. We demonstrate and evaluate the performance of the algorithms in a model with applications to benzene, benzo(a)pyrene, MTBE, TCDD, and tritium.

  13. Reflectance of vegetation, soil, and water

    NASA Technical Reports Server (NTRS)

    Wiegand, C. L. (Principal Investigator)

    1973-01-01

    The author has identified the following significant results. A ratio of MSS channels 5 and 7 (5/7) and 5 to 6 (5/6) signals resulted in a correct recognition of 86.9% of the members of representative crop and soil conditions, compared with recognitions of 60.0, 64.1, 74.1, and 81.4% for channels 4, 5, 6, and 7 taken individually. Based on this result a satellite channel ratio procedure has been developed that enhances line printer gray maps for more efficient experimental test site location in the CCT data. Because independent estimates are not available to judge acreage estmates derived from ERTS-1 data against, except for a few crops, an interpenetrating sample constituting 3.5% of the county is ground truthed periodically. The crop of land uses and their acreages, respectively, as estimated from the interpenetrating samples, are: cotton, 129, 714; sorghum, 182,783; mixed citrus, 53,954; oranges, 16,929; grapefruit, 13,863; rangeland, 137,845; and, improved pastures, 57.169.

  14. Vegetation establishment on soil-amended weathered fly ash

    SciTech Connect

    Semalulu, O.; Barnhisel, R.I.; Witt, S.

    1998-12-31

    A field study was conducted with the following objectives in mind: (1) to study the effect of soil addition to weathered fly ash on the establishment and survival of different grasses and legumes, (2) to identify suitable grasses and/or legume species for vegetation of fly ash, (3) to study the fertilizer N and P requirements for successful vegetation establishment on fly ash and ash-soil mixtures, (4) to examine the nutrient composition of the plant species tested, and (5) to study the plant availability of P from fly ash and ash-soil mixtures. Three rooting media were used: weathered fly ash, and 33% or 50% soil blended with the ash. Four experiments were established on each of these media to evaluate warm season grasses in pure stands, warm season grasses inter-seeded with legumes, cool season grasses, and cool season grasses inter-seeded with legumes. Soil used in this study was more acidic than the fly ash. Only the results from characterization of the rooting media, ground cover, and yield will be presented here.

  15. Fungal communities in soils along a vegetative ecotone.

    PubMed

    Karst, Justine; Piculell, Bridget; Brigham, Christy; Booth, Michael; Hoeksema, Jason D

    2013-01-01

    We investigated the community composition and diversity of soil fungi along a sharp vegetative ecotone between coastal sage scrub (CSS) and nonnative annual grassland habitat at two sites in coastal California. USA- We pooled soil samples across 29 m transects on either side of the ecotone at each of the two sites, and. using clone libraries of fungal ribosomal DNA, we identified 280 operational taxonomic units (OTUs) from a total 40 g soil. We combined information from partial LSU and ITS sequences and found that the majority of OTUs belonged to the phylum Ascomycota, followed by Basidiomycota. Within the Ascomycota. a quarter of OTUs were Sordariomycetes. 17% were Leotiomycet.es, 16% were Dothideomycetes and the remaining OTUs were distributed among the classes Eurotiomycetes, Pezizomycetes, Lecanoromycetes, Orbiliomycetes and Arthoniomycetes. Within the Basidiomycota. all OTUs but one belonged to the subphylum Agaricomycotina. We also sampled plant communities at the same sites to offer a point of comparison for patterns in richness of fungal communities. Fungal communities had higher alpha and beta diversity than plant communities; fungal communities were approximately 20 times as rich as plant communities and the majority of OTUs were found in single soil samples. Soils harbored a unique mycoflora that did not reveal vegetative boundaries or site differences. High alpha and beta diversity and possible sampling artifacts necessitate extensive sampling to reveal differentiation in these fungal communities.

  16. Soil phosphorus forms as quality indicators of soils under different vegetation covers.

    PubMed

    Turrión, María-Belén; López, Olga; Lafuente, Francisco; Mulas, Rafael; Ruipérez, César; Puyo, Alberto

    2007-05-25

    The type of vegetation cover determines the physicochemical and biological properties of the soil over which they are developing. The objective of this study was to determine the effect of different vegetation covers on the forms of soil phosphorus, in order to know which of these forms can be used as a soil quality indicator. The experimental area was located on the acidic plateau at the North of Palencia (North Spain), where an area was selected vegetation covers very close to each other: pine (Pinus sylvestris), oak (Quercus pyrenaica), and three different shrub species (Arctostaphylos uva-ursi, Erica australis and Halimium alyssoides). The Ah horizon was sampled and pH, total organic C (C(org)), total N (N), cationic exchange capacity (CEC), sum of bases (S) and P forms by a sequential fractionation were analysed. Results showed that oak and A. uva-ursi improve the considered soil parameters (pH, C(org)/N ratio, CEC, and S) and provide soils of better quality. Inorganic soil P forms were influenced in greater extent by the vegetation cover than were P organic forms. Labile inorganic P forms could be used as indicators of soil quality. The organic P forms were less sensitive than inorganic ones to the indicated improvements.

  17. Soil water availability as controlling factor for actual evapotranspiration in urban soil-vegetation-systems

    NASA Astrophysics Data System (ADS)

    Thomsen, Simon; Reisdorff, Christoph; Gröngröft, Alexander; Jensen, Kai; Eschenbach, Annette

    2015-04-01

    The City of Hamburg is characterized by a large number of greens, parks and roadside trees: 600.000 trees cover about 14% of the city area, and moreover, 245.000 roadside trees can be found here. Urban vegetation is generally known to positively contribute to the urban micro-climate via cooling by evapotranspiration (ET). The water for ET is predominantly stored in the urban soils. Hence, the actual evapotranspiration (ETa) is - beside atmospheric drivers - determined by soil water availability at the soil surface and in the rooting zones of the respective vegetation. The overall aim of this study is to characterize soil water availability as a regulative factor for ETa in urban soil-vegetation systems. The specific questions addressed are: i) What is the spatio-temporal variation in soil water availability at the study sites? ii) Which soil depths are predominantly used for water uptake by the vegetation forms investigated? and iii) Which are the threshold values of soil water tension and soil water content (Θ), respectively, that limit ETa under dry conditions on both grass-dominated and tree-dominated sites? Three study areas were established in the urban region of Hamburg, Germany. We selected areas featuring both single tree stands and grass-dominated sites, both representing typical vegetation forms in Hamburg. The areas are characterized by relatively dry soil conditions. However, they differ in regard to soil water availability. At each area we selected one site dominated by Common Oak (Quercus ruber L.) with ages from 40 to 120 years, and paired each oak tree site with a neighboring grass-dominated site. All field measurements were performed during the years 2013 and 2014. At each site, we continuously measured soil water tension and Θ up to 160 cm depth, and xylem sap flux of each of three oak trees per site in a 15 min-resolution. Furthermore, we measured soil hydraulic properties as pF-curve, saturated and unsaturated conductivity at all sites

  18. A Methodology for Soil Moisture Retrieval from Land Surface Temperature, Vegetation Index, Topography and Soil Type

    NASA Astrophysics Data System (ADS)

    Pradhan, N. R.

    2015-12-01

    Soil moisture conditions have an impact upon hydrological processes, biological and biogeochemical processes, eco-hydrology, floods and droughts due to changing climate, near-surface atmospheric conditions and the partition of incoming solar and long-wave radiation between sensible and latent heat fluxes. Hence, soil moisture conditions virtually effect on all aspects of engineering / military engineering activities such as operational mobility, detection of landmines and unexploded ordinance, natural material penetration/excavation, peaking factor analysis in dam design etc. Like other natural systems, soil moisture pattern can vary from completely disorganized (disordered, random) to highly organized. To understand this varying soil moisture pattern, this research utilized topographic wetness index from digital elevation models (DEM) along with vegetation index from remotely sensed measurements in red and near-infrared bands, as well as land surface temperature (LST) in the thermal infrared bands. This research developed a methodology to relate a combined index from DEM, LST and vegetation index with the physical soil moisture properties of soil types and the degree of saturation. The advantage in using this relationship is twofold: first it retrieves soil moisture content at the scale of soil data resolution even though the derived indexes are in a coarse resolution, and secondly the derived soil moisture distribution represents both organized and disorganized patterns of actual soil moisture. The derived soil moisture is used in driving the hydrological model simulations of runoff, sediment and nutrients.

  19. The role of soil moisture on the coevolution of soil and vegetation in mountain grasslands

    NASA Astrophysics Data System (ADS)

    Bertoldi, Giacomo; Claudia, Notarnicola; Brenner, Johannes; Castelli, Mariapina; Greifeneder, Felix; Niedrist, Georg; Seeber, Julia; Tappeiner, Ulrike

    2016-04-01

    One of the key variables controlling the organization of vegetation and the coevolution of soils and landforms is soil moisture content (SMC). For this reason, understanding the controls on the spatial and temporal patterns of SMC is essential to predict how perturbations in vegetation and climate will affect mountain ecosystem functioning. In this contribution, we focus on the dynamic of surface SMC of water-limited alpine grasslands in the Long Term Ecological Research area Mazia Valley in the European Alps. We analyze the impacts of different land managements (meadows versus pastures) and its relationships with climate and topography. The area has been equipped since 2009 with a network of more than 20 stations, measuring SMC and climatic variables and with two eddy-covariance stations, measuring surface fluxes over meadows and pastures. Monthly biomass production data have been collected and detailed soil and spatial soil moisture surveys are available. Moreover, high spatial resolution SMC maps have been derived from satellites Synthetic Aperture Radar Radar (SAR) images (Sentinel 1 and RADARSAT2 images). Both ground surveys and remote sensing observations show persistent landscape-level patterns. Meadows, in general located in flatter areas, tend to be wetter. This leads to higher vegetation productivity and to the development of soils with higher water holding capacity, thus to a positive feedback on SMC. In contrast, pastures, located on steeper slopes with lower vegetation density and higher soil erosion, tend to be drier, leading to a negative feedback on SMC and soil development. This co-evolution of land cover and SMC leads therefore to persistent spatial patterns. In order to understand quantitatively such linked interactions, a sensitivity analysis has been performed with the GEOtop hydrological model. Results show how both abiotic (mainly slope and elevation) and anthropogenic (irrigation and soil management) factors exert a significant control on

  20. Coevolution of hydraulic, soil and vegetation processes in estuarine wetlands

    NASA Astrophysics Data System (ADS)

    Trivisonno, Franco; Rodriguez, Jose F.; Riccardi, Gerardo; Saco, Patricia; Stenta, Hernan

    2014-05-01

    Estuarine wetlands of south eastern Australia, typically display a vegetation zonation with a sequence mudflats - mangrove forest - saltmarsh plains from the seaward margin and up the topographic gradient. Estuarine wetlands are among the most productive ecosystems in the world, providing unique habitats for fish and many terrestrial species. They also have a carbon sequestration capacity that surpasess terrestrial forest. Estuarine wetlands respond to sea-level rise by vertical accretion and horizontal landward migration, in order to maintain their position in the tidal frame. In situations in which buffer areas for landward migration are not available, saltmarsh can be lost due to mangrove encroachment. As a result of mangrove invasion associated in part with raising estuary water levels and urbanisation, coastal saltmarsh in parts of south-eastern Australia has been declared an endangered ecological community. Predicting estuarine wetlands response to sea-level rise requires modelling the coevolving dynamics of water flow, soil and vegetation. This paper presents preliminary results of our recently developed numerical model for wetland dynamics in wetlands of the Hunter estuary of NSW. The model simulates continuous tidal inflow into the wetland, and accounts for the effect of varying vegetation types on flow resistance. Coevolution effects appear as vegetation types are updated based on their preference to prevailing hydrodynamic conditions. The model also considers that accretion values vary with vegetation type. Simulations are driven using local information collected over several years, which includes estuary water levels, accretion rates, soil carbon content, flow resistance and vegetation preference to hydraulic conditions. Model results predict further saltmarsh loss under current conditions of moderate increase of estuary water levels.

  1. Vegetation studies on Vandenberg Air Force Base, California

    NASA Technical Reports Server (NTRS)

    Schmalzer, Paul A.; Hickson, Diana E.; Hinkle, C. Ross

    1988-01-01

    Vandenburg Air Force Base, located in coastal central California with an area of 98,400 ac, contains resources of considerable biological significance. Available information on the vegetation and flora of Vandenburg is summarized and new data collected in this project are presented. A bibliography of 621 references dealing with vegetation and related topics related to Vanderburg was compiled from computer and manual literature searches and a review of past studies of the base. A preliminary floristic list of 642 taxa representing 311 genera and 80 families was compiled from past studies and plants identified in the vegetation sampling conducted in this project. Fifty-two special interest plant species are known to occur or were suggested to occur. Vegetation was sampled using permanent plots and transects in all major plant communities including chaparral, Bishop pine forest, tanbark oak forest, annual grassland, oak woodland, coastal sage scrub, purple sage scrub, coastal dune scrub, coastal dunes, box elder riparian woodland, will riparian woodland, freshwater marsh, salt marsh, and seasonal wetlands. Comparison of the new vegetation data to the compostie San Diego State University data does not indicate major changes in most communities since the original study. Recommendations are made for additional studies needed to maintain and extend the environmental data base and for management actions to improve resource protection.

  2. Environmental sensor networks for vegetation, animal and soil sciences

    NASA Astrophysics Data System (ADS)

    Zerger, A.; Viscarra Rossel, R. A.; Swain, D. L.; Wark, T.; Handcock, R. N.; Doerr, V. A. J.; Bishop-Hurley, G. J.; Doerr, E. D.; Gibbons, P. G.; Lobsey, C.

    2010-10-01

    Environmental sensor networks (ESNs) provide new opportunities for improving our understanding of the environment. In contrast to remote sensing technologies where measurements are made from large distances (e.g. satellite imagery, aerial photography, airborne radiometric surveys), ESNs focus on measurements that are made in close proximity to the target environmental phenomenon. Sensors can be used to collect a much larger number of measurements, which are quantitative and repeatable. They can also be deployed in locations that may otherwise be difficult to visit regularly. Sensors that are commonly used in the environmental sciences include ground-based multispectral vegetation sensors, soil moisture sensors, GPS tracking and bioacoustics for tracking movement in wild and domesticated animals. Sensors may also be coupled with wireless networks to more effectively capture, synthesise and transmit data to decision-makers. The climate and weather monitoring domains provide useful examples of how ESNs can provide real-time monitoring of environmental change (e.g. temperature, rainfall, sea-surface temperature) to many users. The objective of this review is to examine state-of-the-art use of ESNs for three environmental monitoring domains: (a) terrestrial vegetation, (b) animal movement and diversity, and (c) soil. Climate and aquatic monitoring sensor applications are so extensive that they are beyond the scope of this review. In each of the three application domains (vegetation, animals and soils) we review the technologies, the attributes that they sense and briefly examine the technical limitations. We conclude with a discussion of future directions.

  3. Transfer of Cadmium from Soil to Vegetable in the Pearl River Delta area, South China

    PubMed Central

    Zhang, Huihua; Chen, Junjian; Zhu, Li; Yang, Guoyi; Li, Dingqiang

    2014-01-01

    The purpose of this study was to investigate the regional Cadmium (Cd) concentration levels in soils and in leaf vegetables across the Pearl River Delta (PRD) area; and reveal the transfer characteristics of Cadmium (Cd) from soils to leaf vegetable species on a regional scale. 170 paired vegetables and corresponding surface soil samples in the study area were collected for calculating the transfer factors of Cadmium (Cd) from soils to vegetables. This investigation revealed that in the study area Cd concentration in soils was lower (mean value 0.158 mg kg−1) compared with other countries or regions. The Cd-contaminated areas are mainly located in west areas of the Pearl River Delta. Cd concentrations in all vegetables were lower than the national standard of Safe vegetables (0.2 mg kg−1). 88% of vegetable samples met the standard of No-Polluted vegetables (0.05 mg kg−1). The Cd concentration in vegetables was mainly influenced by the interactions of total Cd concentration in soils, soil pH and vegetable species. The fit lines of soil-to-plant transfer factors and total Cd concentration in soils for various vegetable species were best described by the exponential equation (), and these fit lines can be divided into two parts, including the sharply decrease part with a large error range, and the slowly decrease part with a low error range, according to the gradual increasing of total Cd concentrations in soils. PMID:25247431

  4. Soil management of copper mine tailing soils--sludge amendment and tree vegetation could improve biological soil quality.

    PubMed

    Asensio, Verónica; Covelo, Emma F; Kandeler, Ellen

    2013-07-01

    Mine soils at the depleted copper mine in Touro (Northwest Spain) are physico-chemically degraded and polluted by chromium and copper. To increase the quality of these soils, some areas at this mine have been vegetated with eucalyptus or pines, amended with sludges, or received both treatments. Four sites were selected at the Touro mine tailing in order to evaluate the effect of these different reclamation treatments on the biological soil quality: (1) Control (untreated), (2) Forest (vegetated), (3) Sludge (amended with sludges) and (4) Forest+Sludge (vegetated and amended). The new approach of the present work is that we evaluated the effect of planting trees or/and amending with sludges on the biological soil quality of mine sites polluted by metals under field conditions. The addition of sludges to mine sites recovered the biological quality of the soil, while vegetating with trees did not increase microbial biomass and function to the level of unpolluted sites. Moreover, amending with sludges increased the efficiency of the soil's microbial community to metabolize C and N, which was indicated by the decrease of the specific enzyme activities and the increase in the ratio Cmic:Nmic (shift towards predominance of fungi instead of bacteria). However, the high Cu and Cr concentrations still have negative influence on the microorganisms in all the treated soils. For the future remediation of mine soils, we recommend periodically adding sludge and planting native legume species.

  5. Improving the vegetation parametrization in the ASCAT soil moisture retrieval

    NASA Astrophysics Data System (ADS)

    Hahn, Sebastian; Wagner, Wolfgang

    2016-04-01

    The TU Wien soil moisture retrieval algorithm is based upon a backscatter model designed to exploit the multi-angle viewing capabilities of space-borne fan-beam scatterometers. In the beginning the backscatter model has been developed for the scatterometers on-board ERS-1 and ERS-2 and later successfully applied on the successor instrument ASCAT (Advanced Scatterometer) on-board the series of Metop satellites. The soil moisture retrieval algorithm represents a physically motivated change detection method, which requires model parameters derived along the way to the final soil moisture estimates. The computation of the model parameters needs to be done in the time domain and is computationally expensive. However, not all model parameters are computationally estimated from the backscatter measurements, but rather defined by empirical observations. The cross-over angles belong to this group of model parameters, which unlike other model parameters, remain spatially and temporally constant on a global scale. This study investigates the possibility to optimize the cross-over angles, which are important parameters for the vegetation correction in the TU Wien soil moisture retrieval algorithm. The optimization is carried out with various cost functions and compared against soil moisture values from land surface models. First results indicate that spatially varying cross-over angles help to improve the mean annual cycle of soil moisture.

  6. The Role of Vegetation Dynamics on the Soil Water Balance in Water-Limited Ecosystems

    NASA Astrophysics Data System (ADS)

    Montaldo, N.; Rondena, R.; Albertson, J. D.; Mancini, M.

    2003-12-01

    The structure and function of the vegetation regulates the exchange of mass, energy and momentum across the biosphere-atmosphere interface. Vegetation dynamics are usually neglected, other than seasonal phenology, in land surface models (LSMs). However, changes in vegetation densities, influencing the partitioning of incoming solar energy into sensible and latent heat fluxes, can result in long-term changes in both local and global climates (e.g., precipitation and temperature), which in turn will feedback to affect the vegetation growth. In semi-arid regions, this may result in persistent drought and desertification, with substantial impacts on the human populations of these regions through reduction in agricultural productivity and reduction in quantity and quality of water supply. With an objective of finding a simple vegetation model able to accurately simulate the leaf area index (LAI) dynamics, vegetation models of different level of complexity (e.g., including or not the modeling of the root biomass or the modeling of the dead biomass) are developed and compared. The vegetation dynamics models are coupled to a LSM, with the vegetation models providing the green biomass and the LAI evolution through time, and the LSM using this information in the computation of the land surface fluxes and updating the soil water content in the root-zone. We explore the models on a case study of a water limited grass field in California. Results show that a simple vegetation model that simulates the living aboveground green biomass (i.e., with low parameterization and computational efforts) is able to accurately simulate the LAI. Results also highlight the importance of including the plant growth model in the LSM when studying the climate-soil-vegetation interactions and the impact of watershed management practices on the scarce water resources over moderate to long time scales. The inclusion of the vegetation model in the LSM is demonstrated to be essential for assessing the

  7. Radar response to vegetation. [soil moisture mapping via microwave backscattering

    NASA Technical Reports Server (NTRS)

    Ulaby, F. T.

    1975-01-01

    Active microwave measurements of vegetation backscatter were conducted to determine the utility of radar in mapping soil moisture through vegetation and mapping crop types. Using a truck-mounted boom, spectral response data were obtained for four crop types (corn, milo, soybeans, and alfalfa) over the 4-8 GHz frequency band, at incidence angles of 0 to 70 degrees in 10-degree steps, and for all four linear polarization combinations. Based on a total of 125 data sets covering a wide range of soil moisture, content, system design criteria are proposed for each of the aforementioned objectives. Quantitative soil moisture determination was best achieved at the lower frequency end of the 4-8 GHz band using HH polarized waves in the 5- to 15-degree incidence angle range. A combination of low and high frequency measurements are suggested for classifying crop types. For crop discrimination, a dual-frequency dual-polarization (VV and cross) system operating at incidence angles above 40 degrees is suggested.

  8. Development of a Multi-experience Approach in Introductory Soil and Vegetation Geography Courses.

    ERIC Educational Resources Information Center

    Limbird, Arthur

    1982-01-01

    Describes an introductory college level course in soil and vegetation which uses lecture, audiovisual tutorial, individualized instruction, field trips, films, and games. The course consists of three segments: basic concepts of soils, basic concepts of plants, and soil and vegetation concepts in a spatial context. (KC)

  9. Soil Respiration Responses to Variation in Temperature Treatment and Vegetation Type

    NASA Astrophysics Data System (ADS)

    Liu, S.; Pavao-zuckerman, M.

    2013-12-01

    Complex linkages exist between terrestrial vegetation, soil moisture, soil organic matter (SOM), local climate, and soil microorganisms. Thus, large-scale changes in vegetation, such as the woody plant encroachment observed in many historically semiarid and arid grasslands worldwide, could potentially alter the flux of carbon from soil reserves to the atmosphere. Mathematical models that attempt to project the long-term impact of vegetative shifts on soil fluxes largely rely on assumptions such as first-order donor control rather than incorporate the biological aspects of soil respiration such as microbial activity. To examine the impact of vegetation type on soil physicochemical properties and soil microbial respiration and provide experimental data to refine existing predictive models, we compared soil (ground basalt from northern Arizona) in mesocosms established with no vegetation, velvet mesquites (Prosopis velutina; woody shrub), or sideoats gramas (Bouteloua curtipendula; grass) for 2 years, The temperature sensitivity of soil respiration was examined by incubating soil (0-10 and 10-30 cm depth fractions) from each vegetation treatment at 10, 20, 30, and 40 °C for 24 hours. Vegetated soils contained more SOM (~0.1% for mesquite and grass mesocosms) than non-vegetated soils (~0.02%). Respiration rates were generally highest from grass-established soils, intermediate from mesquite-established soils, and lowest from non-vegetated soils. Respiration rates of samples incubated without the addition of substrate peaked at approximately 30 °C, whereas respiration rates of samples incubated with dextrose were highest at 40 °C. Further, the respiration assays suggest that while respiration rates are overall higher in grass-established soils, mesquite-established soils are more temperature sensitive which may have significant implications in the context of global warming and current fire management practices.

  10. Active Distributed Temperature Sensing to Characterise Soil Moisture and Heat Dynamics of a Vegetated Hillslope.

    NASA Astrophysics Data System (ADS)

    Ciocca, F.; Krause, S.; Chalari, A.; Hannah, D. M.; Mondanos, M.

    2015-12-01

    Complex correlated water and heat dynamics characterise the land surface and shallow subsurface, as consequence of the concurrent action of multiple transport processes. Point sensors and/or remote techniques show limitations in providing precise measurements of key indicators of soil heat and water transport such as soil temperature and moisture, at both high spatiotemporal resolution and large areal coverage. Fibre optics Distributed Temperature Sensors (DTS) allow for precise temperature measurement along optical cables of up to several kilometres, sampling at resolutions of up to few centimetres in space and seconds in time. The optical cable is the sensor and can be buried in the soil with minimum disturbance, to construct soil temperature profiles, over large surveying areas. Soil moisture can be obtained from the analysis of both heating and cooling rates measured by the DTS, when copper conductors embedded in the optical cable are electrically heated (technique known as Active DTS). In July 2015, three loops of optical cable of 500m each have been buried in the soil at different depths (0.05m, 0.25m and 0.40m), along an inclined recently vegetated field in the Birmingham area, UK. Active DTS tests have been set with the aim to characterize the soil temperature and moisture regimes of the field at high spatial resolution, in response to both sporadic events such as showers or scheduled irrigation, and diurnal fluctuations induced by atmospheric forcing. Spatiotemporal variations of the aforementioned regimes will be used to trace vertical and horizontal soil heat and water movements. Finally, assumptions on the possibility to correlate soil heat and water dynamics to a specific process such as precipitation, evapotranspiration, soil inclination, will be discussed. This research is part of the Marie Curie Initial Training Network (ITN) INTERFACES project and is realised in the context of the Free Air Carbon Enrichment (FACE) experiment, in collaboration with

  11. Vegetation, soil, and flooding relationships in a blackwater floodplain forest

    USGS Publications Warehouse

    Burke, M.K.; King, S.L.; Gartner, D.; Eisenbies, M.H.

    2003-01-01

    Hydroperiod is considered the primary determinant of plant species distribution in temperate floodplain forests, but most studies have focused on alluvial (sediment-laden) river systems. Few studies have evaluated plant community relationships in blackwater river systems of the South Atlantic Coastal Plain of North America. In this study, we characterized the soils, hydroperiod, and vegetation communities and evaluated relationships between the physical and chemical environment and plant community structure on the floodplain of the Coosawhatchie River, a blackwater river in South Carolina, USA. The soils were similar to previous descriptions of blackwater floodplain soils but had greater soil N and P availability, substantially greater clay content, and lower soil silt content than was previously reported for other blackwater river floodplains. Results of a cluster analysis showed there were five forest communities on the site, and both short-term (4 years) and long-term (50 years) flooding records documented a flooding gradient: water tupelo community > swamp tupelo > laurel oak = overcup oak > mixed oak. The long-term hydrologic record showed that the floodplain has flooded less frequently from 1994 to present than in previous decades. Detrended correspondence analysis of environmental and relative basal area values showed that 27% of the variation in overstory community structure could be explained by the first two axes; however, fitting the species distributions to the DCA axes using Gaussian regression explained 67% of the variation. Axes were correlated with elevation (flooding intensity) and soil characteristics related to rooting volume and cation nutrient availability. Our study suggests that flooding is the major factor affecting community structure, but soil characteristics also may be factors in community structure in blackwater systems. ?? 2003, The Society of Wetland Scientists.

  12. The role of vegetation and soil in the biogeochemical cycling of mercury

    NASA Astrophysics Data System (ADS)

    Stamenkovic, Jelena

    The major purpose of this dissertation was to investigate the role plants play in regulating atmospheric Hg exchange with vegetated landscapes at an individual plant, and at ecosystem level. Investigation of ecosystem level measurements showed that large mesocosms could not be used for directly quantifying Hg flux from low-Hg containing substrates without a reliable system blank. Designs that minimize the mesocosm (volume)/(area of interest) ratio are recommended (Chapter 2). Smaller scale plant and soil Hg fluxes quantified using dynamic flux chambers were used to determine the air-surface Hg exchange from tallgrass prairie ecosystem housed in mesocosms (Chapter 3). Plant foliage was found to be a sink for atmospheric Hg, with uptake influenced by plant functional type and age. Emissions of Hg from vegetated and litter-covered soil were lower than fluxes from adjacent bare soil and the difference between the two was seasonally dependent and greatest when canopy coverage was greatest. Thus, an index of plant canopy development (canopy greenness) was used to model Hg flux from vegetated soil. Mass balance for the ecosystem housed in mesocosms showed that the tallgrass prairie was a net sink of atmospheric Hg, annually transferring 7.4 mug Hg m-2 to soil pool. Relative importance of stomatal versus non-stomatal routes of the foliar Hg exchange was assessed (Chapter 4). The non-stomatal route was shown to be an important way of Hg uptake into plant tissue in low humidity air, although details of uptake are not understood. The final objective addressed in this dissertation was to model Hg exchange from three biomes with background Hg concentrations using Geographic Information System (GIS) framework, and evaluate their importance in the regional and global Hg exchange (Chapter 5). Without taking into account foliar Hg uptake from the air, Hg emissions from desert, grassland and deciduous forest in the continental US were roughly estimated to be 5-7 tones per year

  13. Soil warming and CO2 enrichment induce biomass shifts in alpine tree line vegetation.

    PubMed

    Dawes, Melissa A; Philipson, Christopher D; Fonti, Patrick; Bebi, Peter; Hättenschwiler, Stephan; Hagedorn, Frank; Rixen, Christian

    2015-05-01

    Responses of alpine tree line ecosystems to increasing atmospheric CO2 concentrations and global warming are poorly understood. We used an experiment at the Swiss tree line to investigate changes in vegetation biomass after 9 years of free air CO2 enrichment (+200 ppm; 2001-2009) and 6 years of soil warming (+4 °C; 2007-2012). The study contained two key tree line species, Larix decidua and Pinus uncinata, both approximately 40 years old, growing in heath vegetation dominated by dwarf shrubs. In 2012, we harvested and measured biomass of all trees (including root systems), above-ground understorey vegetation and fine roots. Overall, soil warming had clearer effects on plant biomass than CO2 enrichment, and there were no interactive effects between treatments. Total plant biomass increased in warmed plots containing Pinus but not in those with Larix. This response was driven by changes in tree mass (+50%), which contributed an average of 84% (5.7 kg m(-2) ) of total plant mass. Pinus coarse root mass was especially enhanced by warming (+100%), yielding an increased root mass fraction. Elevated CO2 led to an increased relative growth rate of Larix stem basal area but no change in the final biomass of either tree species. Total understorey above-ground mass was not altered by soil warming or elevated CO2 . However, Vaccinium myrtillus mass increased with both treatments, graminoid mass declined with warming, and forb and nonvascular plant (moss and lichen) mass decreased with both treatments. Fine roots showed a substantial reduction under soil warming (-40% for all roots <2 mm in diameter at 0-20 cm soil depth) but no change with CO2 enrichment. Our findings suggest that enhanced overall productivity and shifts in biomass allocation will occur at the tree line, particularly with global warming. However, individual species and functional groups will respond differently to these environmental changes, with consequences for ecosystem structure and functioning.

  14. Soil water and vegetation management for cleanup of selenium contaminated soils

    SciTech Connect

    Not Available

    1989-05-01

    Over the past year scientists have initiatived a new effort aimed at developing a soil water and vegetation management plan for Kesterson Reservoir. The plan is intended to result in a gradual depletion of the inventory of soluble selenium at the Reservoir through a combination agriculturally oriented practices that enhance dissipation of selenium from near surface soils. Agriculturally oriented processes that will contribute to depletion include microbial volatilization from the soils, direct volatilization by living plants, decomposition and volatilization of selenium-bearing vegetation, harvest and removal of seleniferous vegetation, and leaching. The benefits of using this integrated approach are that (1) no single mechanism needs to be relied upon to detoxify the soils, (2) a stable plant community can be established during this period so that impacts to wildlife can be more easily evaluated and controlled, (3) cleanup and management of the site can be carried out in a cost-effective manner. The management plan is also intended to facilitate control over wildlife exposure to selenium contaminated biota by creating a well managed environment. The majority of research associated with this new effort is being carried out at a 200 m by 50 m test plot in Pond 7. A two-line irrigation system , providing local groundwater as an irrigation supply, has been installed. Through an intensive program of soil water sampling, soil gas sampling, vegetation sampling, groundwater monitoring, and soil moisture monitoring, the mass balance for selenium under irrigated conditions is being evaluated. These studies, in conjunction with supplementary laboratory experiments will provide the information needed to develop an optimal management plan for the site. 23 refs., 38 figs., 10 tabs.

  15. Investigation of residual fluoroquinolones in a soil-vegetable system in an intensive vegetable cultivation area in Northern China.

    PubMed

    Li, Xue-Wen; Xie, Yun-Feng; Li, Cang-Lin; Zhao, Hui-Nan; Zhao, Hui; Wang, Ning; Wang, Jin-Feng

    2014-01-15

    One of the largest vegetable cultivation field sites in Northeast China was selected to investigate the occurrence and distribution pattern of fluoroquinolones (FQs) in the soil-vegetable system. A total of 100 surface soil samples and 68 vegetable samples were collected from this study area. The antibiotic concentration was analyzed using high-performance liquid chromatography tandem mass spectrometry. Results indicated the presence of FQs in all soil samples. Ciprofloxacin (CIP) had the highest mean concentration, at 104.4 μg · kg(-1) in the soil, a level that represents a relatively high risk to the environment and to human health. However, in the vegetable samples, norfloxacin (NOR) was significantly higher than CIP and enrofloxacin (ENR), ranging from 18.2 to 658.3 μg · kg(-1). The transfer ability of NOR in soil-vegetables is greater than that of CIP and ENR. Moreover, we found that the solanaceous fruits had a higher antibiotic accumulation ability than the leafy vegetables. Taken together, these data indicate that greater attention should be paid to the region in which vegetables with higher accumulation ability are grown.

  16. Electromagnetic wave scattering from vegetation (Potato) and vegetation covered soil moisture for remote sensing

    NASA Astrophysics Data System (ADS)

    Singh, Keshev

    In the country with limited resources, where the nutrition level of the population has to be maintained under inhospitable situation, the potato has a special value as food. Therefore efforts should be made for improvement and spreading the cultivation of this important crop. It demands an effective program that may provide information about potato growing areas and the growth conditions. Remote sensing has been acknowledged to be a valuable source of spatially comprehensive and temporally repeatable information of crop covered soil moisture, crop growth climatic information etc, which is useful and necessary for agriculture purposes. For this purpose, microwave remote sensing has evolved as an important tool. Since microwave are able to penetrate more deeply into vegetation and underneath ground surface. It is also preferred to the optical frequency band because microwave can work in all type of weather and have a wide signal dynamic range compared optical wavelengths. However interpretation of microwave scattering from agricultural crops requires an understanding the interaction among microwave, vegetative material and the soil. In order to develop useful forward and inverse models for retrieving the vegetation characteristic, it is necessary to know in detail the dielectric properties and plant structure of the vegetation over the range of expected growing conditions. In this paper, a theoretical model based on microwave interaction with potato crop along with examination of biomass of potato crop with the varying underlying soil moisture is studied. For this purpose, X-band (9.5GHz) scatterometer is used for studying the interaction of microwave with potato crop biomass and underlying soil moisture at various sensor parameters (i.e. angular variation and polarization, HH- and VV-). Although there may be a lot of crop parameters (i.e. crop height, leaf area index, etc) which also gives their effect on microwave. All this parameters are interlinked in the crop

  17. [Responses of soil enzyme activities to re-vegetation in gully Loess Plateau of Northwest China].

    PubMed

    Li, Lin-Hai; Qiu, Li-Ping; Meng, Meng

    2012-12-01

    In combining field investigation with laboratory analysis, this paper studied the distribution characteristics of soil enzyme activities along the soil profiles and natural slopes with different re-vegetation treatments in gully Loess Plateau, aimed to assess the responses of the soil enzyme activities to re-vegetation. In the study area, the activities of soil urease, invertase and alkaline phosphatase along natural slopes were highly varied, but the activity of soil catalase was in adverse. The profile distribution of the soil enzyme activities varied significantly with vegetation type, and with increasing soil depth, the activities of soil urease, invertase and alkaline phosphatase decreased while the catalase activity increased. There existed significant positive correlation among the three hydrolases activities. The activities of the three hydrolases were all significantly negatively correlated with soil physical properties and positively correlated with soil chemical properties, while the soil catalase activity was positively correlated with soil moisture content and pH and negatively correlated with other soil physiochemical properties. It was suggested that the activities of soil urease, invertase and alkaline phosphatase in gully Loess Plateau could be used as the sensitive indicators for the soil responses to the re-vegetation in the Plateau, and re-vegetation could improve the biological properties in both surface and deeper soil layers.

  18. Productivity of wet soils: Biomass of cultivated and natural vegetation

    SciTech Connect

    Johnston, C.A.

    1988-12-01

    Wet soils, soils which have agronomic limitations because of excess water, comprise 105 million acres of non-federal land in the conterminous United States. Wet soils which support hydrophytic plants are ''wetlands'', and are some of the most productive natural ecosystems in the world. When both above- and belowground productivity are considered, cattail (Typha latifolia) is the most productive temperate wetland species (26.4 Mg/ha/year). Both cattail and reed (Phragmites australis) have aboveground productivities of about 13 Mg/ha/year. Although average aboveground yields of reed canarygrass (Phalaris arundinacea) are lower (9.5 Mg/ha/year), techniques for its establishment and cultivation are well-developed. Other herbaceous wetland species which show promise as biomass crops include sedge (Carex spp.), river bulrush (Scirpus fluviatilis) and prairie cordgrass (Spartina pectinata). About 40% of wet soils in the conterminous US are currently cultivated, and they produce one-quarter of the major US crops. Most of this land is artificially drained for crops such as corn, soybeans, and vegetables. US wetlands are drained for agriculture at the rate of 223,000 ha/yr. Paddies flooded with water are used to grow rice, cranberries, and wild rice. Forage and live sphagnum moss are products of undrained wetlands. A number of federal and state regulations apply to the draining or irrigation of wetlands, but most do not seriously restrict their use for agriculture. 320 refs., 36 tabs.

  19. Selecting iodine-enriched vegetables and the residual effect of iodate application to soil.

    PubMed

    Dai, Jiu-Lan; Zhu, Yong-Guan; Zhang, Min; Huang, Yi-Zhong

    2004-12-01

    A greenhouse pot experiment was conducted to select vegetables for iodine uptake. The residual effect of iodate fertilization on the growth of and iodine uptake by spinach plants were also investigated. Six vegetables, including leafy vegetables (pakchoi [Brassica chinensis L.], spinach [Spinacia oleracea L.]), tuber vegetables (onion [Allium cepa L.]), shoot vegetables (water spinach [Ipomoea aquatica Forsk.], celery [Apium graveolens L.]), and root vegetables (carrot [Daucus carota var. sativa DC.]) were examined. Results showed that the concentrations of iodate in soil had significant effect on the biomass of edible parts of pakchoi and spinach (p<0.01), whereas the concentrations of iodate in soil had no significant effect on that of carrots, water spinach, celery, and onion. Iodine concentrations in edible parts of vegetables and the transfer factors (TFedible parts) of soil-to-edible parts of vegetables significantly increased with increasing iodine concentrations in soil (p<0.001), and iodine concentrations in edible parts and TFedible parts of spinach were much higher than those of other vegetables at any treatment. Both transfer coefficients for edible parts (TCedible parts) and for aerial parts (TCaerial parts) of vegetables changed differently with increasing iodine concentrations in the soil, and TCedible parts and TCaerial parts of spinach were higher than those of other vegetables. Therefore, spinach was considered as an efficient vegetable for iodine biofortification. Further experiment showed that there is considerable residual effect of soil fertilization with iodate.

  20. Development and validation of a dynamical atmosphere-vegetation-soil HTO transport and OBT formation model.

    PubMed

    Ota, Masakazu; Nagai, Haruyasu

    2011-09-01

    A numerical model simulating transport of tritiated water (HTO) in atmosphere-soil-vegetation system, and, accumulation of organically bound tritium (OBT) in vegetative leaves was developed. Characteristic of the model is, for calculating tritium transport, it incorporates a dynamical atmosphere-soil-vegetation model (SOLVEG-II) that calculates transport of heat and water, and, exchange of CO(2). The processes included for calculating tissue free water tritium (TFWT) in leaves are HTO exchange between canopy air and leaf cellular water, root uptake of aqueous HTO in soil, photosynthetic assimilation of TFWT into OBT, and, TFWT formation from OBT through respiration. Tritium fluxes at the last two processes are input to a carbohydrate compartment model in leaves that calculates OBT translocation from leaves and allocation in them, by using photosynthesis and respiration rate in leaves. The developed model was then validated through a simulation of an existing experiment of acute exposure of grape plants to atmospheric HTO. Calculated TFWT concentration in leaves increased soon after the start of HTO exposure, reaching to equilibrium with the atmospheric HTO within a few hours, and then rapidly decreased after the end of the exposure. Calculated non-exchangeable OBT amount in leaves linearly increased during the exposure, and after the exposure, rapidly decreased in daytime, and, moderately nighttime. These variations in the calculated TFWT concentrations and OBT amounts, each mainly controlled by HTO exchange between canopy air and leaf cellular water and by carbohydrates translocation from leaves, fairly agreed with the observations within average errors of a factor of two.

  1. Vegetation and soils field research data base: Experiment summaries

    NASA Technical Reports Server (NTRS)

    Biehl, L. L.; Daughtry, C. S. T.; Bauer, M. E.

    1984-01-01

    Understanding of the relationships between the optical, spectral characteristics and important biological-physical parameters of earth-surface features can best be obtained by carefully controlled studies over fields and plots where complete data describing the condition of targets are attainable and where frequent, timely spectral measurement can be obtained. Development of a vegetation and soils field research data base was initiated in 1972 at Purdue University's Laboratory for Applications of Remote Sensing and expanded in the fall of 1974 by NASA as part of LACIE. Since then, over 250,000 truck-mounted and helicopter-borne spectrometer/multiband radiometer observations have been obtained of more than 50 soil series and 20 species of crops, grasses, and trees. These data are supplemented by an extensive set of biophysical and meteorological data acquired during each mission. The field research data form one of the most complete and best-documented data sets acquired for agricultural remote sensing research. Thus, they are well-suited to serve as a data base for research to: (1) quantiatively determine the relationships of spectral and biophysical characteristics of vegetation, (2) define future sensor systems, and (3) develop advanced data analysis techniques.

  2. Challenges in Ecohydrological Monitoring at Soil-Vegetation Interfaces: Exploiting the Potential for Fibre Optic Technologies

    NASA Astrophysics Data System (ADS)

    Chalari, A.; Ciocca, F.; Krause, S.; Hannah, D. M.; Blaen, P.; Coleman, T. I.; Mondanos, M.

    2015-12-01

    The Birmingham Institute of Forestry Research (BIFoR) is using Free-Air Carbon Enrichment (FACE) experiments to quantify the long-term impact and resilience of forests into rising atmospheric CO2 concentrations. The FACE campaign critically relies on a successful monitoring and understanding of the large variety of ecohydrological processes occurring across many interfaces, from deep soil to above the tree canopy. At the land-atmosphere interface, soil moisture and temperature are key variables to determine the heat and water exchanges, crucial to the vegetation dynamics as well as to groundwater recharge. Traditional solutions for monitoring soil moisture and temperature such as remote techniques and point sensors show limitations in fast acquisition rates and spatial coverage, respectively. Hence, spatial patterns and temporal dynamics of heat and water fluxes at this interface can only be monitored to a certain degree, limiting deeper knowledge in dynamically evolving systems (e.g. in impact of growing vegetation). Fibre optics Distributed Temperature Sensors (DTS) can measure soil temperatures at high spatiotemporal resolutions and accuracy, along kilometers of optical cable buried in the soil. Heat pulse methods applied to electrical elements embedded in the optical cable can be used to obtain the soil moisture. In July 2015 a monitoring system based on DTS has been installed in a recently forested hillslope at BIFoR in order to quantify high-resolution spatial patterns and high-frequency temporal dynamics of soil heat fluxes and soil moisture conditions. Therefore, 1500m of optical cables have been carefully deployed in three overlapped loops at 0.05m, 0.25m and 0.4m from the soil surface and an electrical system to send heat pulses along the optical cable has been developed. This paper discussed both, installation and design details along with first results of the soil moisture and temperature monitoring carried out since July 2015. Moreover, interpretations

  3. The concentrations, distribution and sources of PAHs in agricultural soils and vegetables from Shunde, Guangdong, China.

    PubMed

    Li, Yong Tao; Li, Fang Bai; Chen, Jun Jian; Yang, Guo Yi; Wan, Hong Fu; Zhang, Tian Bin; Zeng, Xiao Duo; Liu, Jian Ming

    2008-04-01

    The concentrations, distribution and sources of 16 polycyclic aromatic hydrocarbons (PAHs) were determined in 30 agricultural soil and 16 vegetable samples collected from subtropical Shunde area, an important manufacturing center in China. The total PAHs ranged from 33.7 to 350 microg/kg in soils, and 82 to 1,258 microg/kg in vegetables. The most abundant individual PAHs are phenanthrene, fluoranthene, chrysene, pyrene and benzo(b)fluoranthene for soil samples, and anthracene, naphthalene, phenanthrene, pyrene and chrysene for vegetable samples. Average vegetable-soil ratios of total PAHs were 2.20 for leafy vegetables and 1.27 for fruity vegetables. Total PAHs in vegetable samples are not significantly correlated to those in corresponding soil samples. Principal component analyses were conducted to distinguish samples on basis of their distribution in each town, soil type and vegetable specie. Relatively abundant soil PAHs were found in town Jun'an, Beijiao, Chencun, Lecong and Ronggui, while abundant vegetable PAHs were observed in town Jun'an, Lecong, Xingtan, Daliang and Chenchun. The highest level of total PAHs were found in vegetable soil, followed by pond sediment and "stacked soil" on pond banks. The PAHs contents in leafy vegetables are higher than those in fruity vegetables. Some PAH compound ratios suggest the PAHs derived from incomplete combustion of petroleum, coal and refuse from power generation and ceramic manufacturing, and paint spraying on furniture, as well as sewage irrigation from textile industries. Soil PAHs contents have significant logarithmic correlation with total organic carbon, which demonstrates the importance of soil organic matter as sorbent to prevent losses of PAHs.

  4. Transregional Collaborative Research Centre 32: Patterns in Soil-Vegetation

    NASA Astrophysics Data System (ADS)

    Kollet, S. J.; Simmer, C.; Masbou, M.; Boessenkool, K.; Crewell, S.; Diekkruger, B.; Huber, K.; Klitzsch, N.; Koyama, C. N.; Vereecken, H.

    2011-12-01

    The soil, vegetation and the lower atmosphere (SVA) are key compartments of the Earth, where almost all activities of mankind take place. This region is characterized by extremely complex patterns, structures and processes that act at different temporal and spatial scales. While the exchange of energy, water and carbon is continuous between the different compartments, the pertinent fluxes are strongly heterogeneous and variable in space and time. The overarching TR32 paradigm is that the characterisation of structures and patterns will lead to a deeper qualitative and quantitative understanding of the SVA system, and ultimately to better predictions of the SVA state. The TR32 combines research groups in the field of soil and plant science, remote sensing, hydrology, meteorology and mathematics located at the Universities of Aachen, Bonn, Braunschweig and Cologne and the Research Centre Juelich study the soil-vegetation atmosphere system under the novel holistic paradigm of patterns. To understand the mechanisms leading to spatial and temporal patterns in energy and matter fluxes of the SVA system we link experiments and theory via model-observation integration. Focusing our research on the Rur Catchment (Germany), patterns are monitored since 2006 continuously using existing and novel geophysical and remote sensing techniques from the local to the catchment scale based on ground penetrating radar methods, induced polarization, radiomagnetotellurics, electrical resistivity tomography, boundary layer scintillometry, lidar techniques, microwave radiometry, and precipitation radars with polarization diversity. Modeling approaches involve high resolution numerical weather prediction (NWP; 400m) and hydrological models (few meters). Example work from the first phase includes the transfer of laboratory methods to the field; the measurements of patterns of soil-carbon, evapotranspiration and respiration measured in the field; catchment-scale modeling of exchange processes

  5. Management effects on soil quality in organic vegetable systems in western Washington

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Management practices in organic vegetable cropping systems and their contributions toward sustainable farming practices can differ greatly. Soil quality monitoring may help organic farmers evaluate and choose best management practices. This study 1) assessed the sensitivity of soil biological prop...

  6. Trends in soil-vegetation dynamics in burned Mediterranean pine forests: the effects of soil properties

    NASA Astrophysics Data System (ADS)

    Wittenberg, L.; Malkinson, D.

    2009-04-01

    Fire can impact a variety of soil physical and chemical properties. These changes may result, given the fire severity and the local conditions, in decreased infiltration and increased runoff and erosion rates. Most of these changes are caused by complex interactions among eco-geomorphic processes which affect, in turn, the rehabilitation dynamics of the soil and the regeneration of the burnt vegetation. Following wildfire events in two forests growing on different soil types, we investigated runoff, erosion, nutrient export (specifically nitrogen and phosphorous) and vegetation recovery dynamics. The Biriya forest site, burned during the 2006 summer, is composed of two dominant lithological types: soft chalk and marl which are relatively impermeable. The rocks are usually overlain by relatively thick, up of to 80 cm, grayish-white Rendzina soil, which contains large amounts of dissolved carbonate. These carbonates serve as a limiting factor for vegetation growth. The planted forest in Biriya is comprised of monospecific stands of Pinus spp. and Cupressus spp. The Mt. Carmel area, which was last burned in the 2005 spring, represents a system of varied Mediterranean landscapes, differentiated by lithology, soils and vegetation. Lithology is mainly composed of limestone, dolomite, and chalk. The dominant soil is Brown Rendzina whilst in some locations Grey Rendzina and Terra Rossa can be found. The local vegetation is composed mainly of a complex of pine (Pinus halepensis), oak (Quercus calliprinos), Pistacia lentiscus and associations At each site several 3X3 m monitoring plots were established to collect runoff and sediment. In-plot vegetation changes were monitored by a sequence of aerial photographs captured using a 6 m pole-mounted camera. At the terra-rosa sites (Mt. Carmel) mean runoff coefficients were 2.18% during the first year after the fire and 1.6% in the second. Mean erosion rates also decreased, from 42 gr/m2 to 4 gr/m2. The recovering vegetation was

  7. Estimation of arsenic in agricultural soils using hyperspectral vegetation indices of rice.

    PubMed

    Shi, Tiezhu; Liu, Huizeng; Chen, Yiyun; Wang, Junjie; Wu, Guofeng

    2016-05-05

    This study systematically analyzed the performance of multivariate hyperspectral vegetation indices of rice (Oryza sativa L.) in estimating the arsenic content in agricultural soils. Field canopy reflectance spectra was obtained in the jointing-booting growth stage of rice. Newly developed and published multivariate vegetation indices were initially calculated to estimate soil arsenic content. The well-performing vegetation indices were then selected using successive projections algorithm (SPA), and the SPA selected vegetation indices were adopted to calibrate a multiple linear regression model for estimating soil arsenic content. Results showed that a three-band vegetation index (R716-R568)/(R552-R568) performed best in the newly developed vegetation indices in estimating soil arsenic content. The photochemical reflectance index (PRI) and red edge position (REP) performed well in the published vegetation indices. Moreover, the linear combination of two vegetation indices ((R716-R568)/(R552-R568) and REP) selected using SPA improved the estimation of soil arsenic content. These results indicated that the newly developed three-band vegetation index (R716-R568)/(R552-R568) might be recommended as an indicator for estimating soil arsenic content in the study area. PRI and REP could be used as universal vegetation indices for monitoring soil arsenic contamination.

  8. Scale Dependence of Soil Permeability to Air: Measurement Method and Field Investigation

    SciTech Connect

    Garbesi, K.; Sextro, R.G.; Robinson, Arthur L.; Wooley, J.D.; Owens, J.A.; Nazaroff, W.W.

    1995-11-01

    This work investigates the dependence soil air-permeability on sampling scale in near-surface unsaturated soils. A new dual-probe dynamic pressure technique was developed to measure permeability in situ over different length scales and different spatial orientations in the soil. Soils at three sites were studied using the new technique. Each soil was found to have higher horizontal than vertical permeability. Significant scale dependence of permeability was also observed at each site. Permeability increased by a factor of 20 as sampling scale increased from 0.1 to 2 m in a sand soil vegetated with dry grass, and by a factor of 15 as sampling scale increased from 0.1 to 3.5 m in a sandy loam with mature Coast Live Oak trees (Quercus agrifolia). The results indicate that standard methods of permeability assessment can grossly underestimate advective transport of gas-phase contaminants through soils.

  9. Scale Dependence of Soil Permeability to Air: Measurement Method and Field Investigation

    NASA Astrophysics Data System (ADS)

    Garbesi, Karina; Sextro, Richard G.; Robinson, Allen L.; Wooley, John D.; Owens, Jonathan A.; Nazaroff, William W.

    1996-03-01

    This work investigates the dependence of soil permeability to air on sampling scale in near-surface unsaturated soils. A new dual-probe dynamic pressure technique was developed to measure permeability in situ over different length scales and different spatial orientations in the soil. Soils at three sites were studied using the new technique. Each soil was found to have higher horizontal than vertical permeability. Significant scale dependence of permeability was also observed at each site. Permeability increased by a factor of 20 as sampling scale increased from 0.1 to 2 m in a sand soil vegetated with dry grass, and by a factor of 15 as sampling scale increased from 0.1 to 3.5 m in a sandy loam with mature Coast Live Oak trees (Quercus agrifolia). The results indicate that standard methods of permeability assessment can grossly underestimate advective transport of gas phase contaminants through soils.

  10. [Evaluation on environmental quality of heavy metals in soils and vegetables based on geostatistics and GIS].

    PubMed

    Xie, Zheng-miao; Li, Jing; Wang, Bi-ling; Chen, Jian-jun

    2006-10-01

    Contents of heavy metals (Pb, Zn, Cd, Cu) in soils and vegetables from Dongguan town in Shangyu city, China were studied using geostatistical analysis and GIS technique to evaluate environmental quality. Based on the evaluation criteria, the distribution of the spatial variability of heavy metals in soil-vegetable system was mapped and analyzed. The results showed that the distribution of soil heavy metals in a large number of soil samples in Dongguan town was asymmetric. The contents of Zn and Cu were lower than those of Cd and Pb. The concentrations distribution of Pb, Zn, Cd and Cu in soils and vegetables were different in spatial variability. There was a close relationship between total and available contents of heavy metals in soil. The contents of Pb and Cd in green vegetables were higher than those of Zn and Cu and exceeded the national sanitation standards for vegetables.

  11. Variations in Soil Microbial Biomass Carbon and Soil Dissolved Organic Carbon in the Re-Vegetation of Hilly Slopes with Purple Soil.

    PubMed

    Yang, Ning; Zou, Dongsheng; Yang, Manyuan; Lin, Zhonggui

    2016-01-01

    Crust restoration is increasingly being done but we lack quantitative information on soil improvements. The study aimed to elucidate the dynamics involving soil microbial biomass carbon and soil dissolved organic carbon in the re-vegetation chronosequences of a hillslope land with purple soil in Hengyang, Hunan Province. The soil can cause serious disasters with both soil erosion and seasonal drought, and also becomes a typical representative of ecological disaster area in South China. Using the space-for-time method, we selected six typical sampling plots, designated as follows: grassplot community, meadow thicket community, frutex community, frutex and arbor community, arbor community, and top-level vegetation community. These plots were established to analyze the changes in soil microbial biomass carbon, soil microbial quotien, dissolved organic carbon, dissolved organic carbon/soil organic carbon, and soil basal respiration in 0-10, 10-20, and 20-40 cm soil layers. The relationships of these parameters with soils physic-chemical properties were also determined. The ecological environment of the 6 plant communities is similar and typical; they denoted six different successive stages of restoration on hillslopes with purple soils in Hengyang, Hunan Province. The soil microbial biomass carbon and soil basal respiration contents decreased with increasing soil depth but increased with re-vegetation. By contrast, soil microbial quotient increased with increasing soil depth and re-vegetation. From 0-10 cm soil layer to 20-40 cm soil layer, the dissolved organic carbon content decreased in different re-vegetation stages. In the process of re-vegetation, the dissolved organic carbon content increased in the 0-10 and 10-20 cm soil layers, whereas the dissolved organic carbon content decreased after an initial increase in the 20-40 cm soil layers. Meanwhile, dissolved organic carbon/soil organic carbon increased with increasing soil depth but decreased with re-vegetation

  12. Variations in Soil Microbial Biomass Carbon and Soil Dissolved Organic Carbon in the Re-Vegetation of Hilly Slopes with Purple Soil

    PubMed Central

    Yang, Ning; Zou, Dongsheng; Yang, Manyuan; Lin, Zhonggui

    2016-01-01

    Crust restoration is increasingly being done but we lack quantitative information on soil improvements. The study aimed to elucidate the dynamics involving soil microbial biomass carbon and soil dissolved organic carbon in the re-vegetation chronosequences of a hillslope land with purple soil in Hengyang, Hunan Province. The soil can cause serious disasters with both soil erosion and seasonal drought, and also becomes a typical representative of ecological disaster area in South China. Using the space-for-time method, we selected six typical sampling plots, designated as follows: grassplot community, meadow thicket community, frutex community, frutex and arbor community, arbor community, and top-level vegetation community. These plots were established to analyze the changes in soil microbial biomass carbon, soil microbial quotien, dissolved organic carbon, dissolved organic carbon/soil organic carbon, and soil basal respiration in 0–10, 10–20, and 20–40 cm soil layers. The relationships of these parameters with soils physic-chemical properties were also determined. The ecological environment of the 6 plant communities is similar and typical; they denoted six different successive stages of restoration on hillslopes with purple soils in Hengyang, Hunan Province. The soil microbial biomass carbon and soil basal respiration contents decreased with increasing soil depth but increased with re-vegetation. By contrast, soil microbial quotient increased with increasing soil depth and re-vegetation. From 0–10 cm soil layer to 20–40 cm soil layer, the dissolved organic carbon content decreased in different re-vegetation stages. In the process of re-vegetation, the dissolved organic carbon content increased in the 0–10 and 10–20 cm soil layers, whereas the dissolved organic carbon content decreased after an initial increase in the 20–40 cm soil layers. Meanwhile, dissolved organic carbon/soil organic carbon increased with increasing soil depth but decreased

  13. [Physicochemical and biological characteristics of coastal saline soil under different vegetation cover].

    PubMed

    Zhou, Jian; Li, Gang; Zhou, Jian; Qin, Pei

    2011-04-01

    Taking seven plots of coastal saline soil under different vegetation cover in North Jiangsu as study sites, this paper studied the seasonal fluctuations of soil basic physicochemical and biological characteristics, and analyzed the relationships between these fluctuations and vegetation cover. In the test plots, there was a greater variability of soil basic physicochemical and biological characteristics. The average soil electrical conductivity was lower in crop plots (0.95 dS m(-1)) than in natural vegetation plots (2.77 dS m(-1)), but parts of the crop plots showed an increased soil electrical conductivity compared with pre-planting. Overall, the soil fertility of the plots was generally at a low level, with the hydrolysable nitrogen content averagely lower than 50 mg kg(-1), available phosphorus content (except fertilized plots) lower than 3 mg kg(-1), and organic matter content less than 1%. Due to fertilization, the soil conditions in crop plots somewhat improved. For the test coastal saline soil, its electrical conductivity and nutrient level were the key factors affecting the vegetation distribution and plant growth, and soil electrical conductivity was most important. There existed close correlations between soil nitrogen and phosphorus contents and soil microbial amount. The seasonal fluctuations of soil characteristics were closely related with vegetation type and human disturbance, being relatively stable under higher vegetation coverage and lesser human disturbance, and dramatic in bare land and castor experimental plots.

  14. Winter Soil Respiration from Different Vegetation Patches in the Yellow River Delta, China

    NASA Astrophysics Data System (ADS)

    Han, Guangxuan; Yu, Junbao; Li, Huabing; Yang, Liqiong; Wang, Guangmei; Mao, Peili; Gao, Yongjun

    2012-07-01

    Vegetation type and density exhibited a considerable patchy distribution at very local scales in the Yellow River Delta, due to the spatial variation of soil salinity and water scarcity. We proposed that soil respiration is affected by the spatial variations in vegetation type and soil chemical properties and tested this hypothesis in three different vegetation patches ( Phragmites australis, Suaeda heteroptera and bare soil) in winter (from November 2010 to April 2011). At diurnal scale, soil respiration all displayed single-peak curves and asymmetric patterns in the three vegetation patches; At seasonal scale, soil respiration all declined steadily until February, and then increased to a peak in next April. But, the magnitude of soil respiration showed significant differences among the three sites. Mean soil respiration rates in winter were 0.60, 0.45 and 0.17 μmol CO2 m-2 s-1 for the Phragmites australis, Suaeda heteroptera and bare soil, respectively. The combined effect of soil temperature and soil moisture accounted for 58-68 % of the seasonal variation of winter soil respiration. The mean soil respiration revealed positive and linear correlations with total N, total N and SOC storages at 0-20 cm depth, and plant biomass among the three sites. We conclude that the patchy distribution of plant biomass and soil chemical properties (total C, total N and SOC) may affect decomposition rate of soil organic matter in winter, thereby leading to spatial variations in soil respiration.

  15. Evaluation of soil and vegetation response to drought using SMOS soil moisture satellite observations

    NASA Astrophysics Data System (ADS)

    Piles, Maria; Sánchez, Nilda; Vall-llossera, Mercè; Ballabrera, Joaquim; Martínez, Justino; Martínez-Fernández, José; Camps, Adriano; Font, Jordi

    2014-05-01

    Soil moisture plays an important role in determining the likelihood of droughts and floods that may affect an area. Knowledge of soil moisture distribution as a function of time and space is highly relevant for hydrological, ecological and agricultural applications, especially in water-limited or drought-prone regions. However, measuring soil moisture is challenging because of its high variability; point-scale in-situ measurements are scarce being remote sensing the only practical means to obtain regional- and global-scale soil moisture estimates. The ESA's Soil Moisture and Ocean Salinity (SMOS) is the first satellite mission ever designed to measuring the Earth's surface soil moisture at near daily time scales with levels of accuracy previously not attained. Since its launch in November 2009, significant efforts have been dedicated to validate and fine-tune the retrieval algorithms so that SMOS-derived soil moisture estimates meet the standards required for a wide variety of applications. In this line, the SMOS Barcelona Expert Center (BEC) is distributing daily, monthly, and annual temporal averages of 0.25-deg global soil moisture maps, which have proved useful for assessing drought and water-stress conditions. In addition, a downscaling algorithm has been developed to combine SMOS and NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) data into fine-scale (< 1km) soil moisture estimates, which permits extending the applicability of the data to regional and local studies. Fine-scale soil moisture maps are currently limited to the Iberian Peninsula but the algorithm is dynamic and can be transported to any region. Soil moisture maps are generated in a near real-time fashion at BEC facilities and are used by Barcelona's fire prevention services to detect extremely dry soil and vegetation conditions posing a risk of fire. Recently, they have been used to explain drought-induced tree mortality episodes and forest decline in the Catalonia region. These

  16. Concentrations of lead, cadmium and barium in urban garden-grown vegetables: the impact of soil variables

    PubMed Central

    McBride, Murray B.; Shayler, Hannah A.; Spliethoff, Henry M.; Mitchell, Rebecca G.; Marquez-Bravo, Lydia G.; Ferenz, Gretchen S.; Russell-Anelli, Jonathan M.; Casey, Linda; Bachman, Sharon

    2014-01-01

    Paired vegetable/soil samples from New York City and Buffalo, NY, gardens were analyzed for lead (Pb), cadmium (Cd) and barium (Ba). Vegetable aluminum (Al) was measured to assess soil adherence. Soil and vegetable metal concentrations did not correlate; vegetable concentrations varied by crop type. Pb was below health-based guidance values (EU standards) in virtually all fruits. 47% of root crops and 9% of leafy greens exceeded guidance values; over half the vegetables exceeded the 95th percentile of market-basket concentrations for Pb. Vegetable Pb correlated with Al; soil particle adherence/incorporation was more important than Pb uptake via roots. Cd was similar to market-basket concentrations and below guidance values in nearly all samples. Vegetable Ba was much higher than Pb or Cd, although soil Ba was lower than soil Pb. The poor relationship between vegetable and soil metal concentrations is attributable to particulate contamination of vegetables and soil characteristics that influence phytoavailability. PMID:25163429

  17. Concentrations of lead, cadmium and barium in urban garden-grown vegetables: the impact of soil variables.

    PubMed

    McBride, Murray B; Shayler, Hannah A; Spliethoff, Henry M; Mitchell, Rebecca G; Marquez-Bravo, Lydia G; Ferenz, Gretchen S; Russell-Anelli, Jonathan M; Casey, Linda; Bachman, Sharon

    2014-11-01

    Paired vegetable/soil samples from New York City and Buffalo, NY, gardens were analyzed for lead (Pb), cadmium (Cd) and barium (Ba). Vegetable aluminum (Al) was measured to assess soil adherence. Soil and vegetable metal concentrations did not correlate; vegetable concentrations varied by crop type. Pb was below health-based guidance values (EU standards) in virtually all fruits. 47% of root crops and 9% of leafy greens exceeded guidance values; over half the vegetables exceeded the 95th percentile of market-basket concentrations for Pb. Vegetable Pb correlated with Al; soil particle adherence/incorporation was more important than Pb uptake via roots. Cd was similar to market-basket concentrations and below guidance values in nearly all samples. Vegetable Ba was much higher than Pb or Cd, although soil Ba was lower than soil Pb. The poor relationship between vegetable and soil metal concentrations is attributable to particulate contamination of vegetables and soil characteristics that influence phytoavailability.

  18. Ecological assessment of a region with PCB emissions using samples of soil, vegetation and breast milk: a case study.

    PubMed

    Bobovnikova, T; Dibtseva, A; Mitroshkov, A; Pleskachevskaya, G

    1993-11-01

    An ecological assessment is performed by using a data bank of air, soil, vegetation and biology data from the area of a capacitor plant in Serpukhov, Russia. Over a number of years the use of PCBs for filling capacitors has brought about environmental contamination beyond the plant's sanitary zone, in particular along a stream where vegetables and berries are grown commercially. A correlation has been found between abnormally high concentrations of PCBs in breast milk of women living in the proximity of the plant and the occurrence of diathesis in babies. A number of remedial measures have been developed in conjunction with the city's sanitary service.

  19. Solar Park Impacts on Air and Soil Microclimate

    NASA Astrophysics Data System (ADS)

    Armstrong, A.; Ostle, N. J.; Whitaker, J.

    2015-12-01

    The drive towards low carbon energy sources and increasing energy demand has resulted in a rapid rise in solar photovoltaics across the world. A substantial proportion of photovoltaics are large-scale ground-mounted systems, solar parks, causing a notable land use change. While the impacts of photovoltaic panel production and disposal have been considered, the consequences of the operation of solar parks on the hosting landscape are poorly resolved. Here, we present data which demonstrates that a solar park sited on permanent grassland in the UK significantly impacted the air and soil microclimate. Specifically, we observed (1) cooler soil under the photovoltaic panels during the summer and between the photovoltaic panel rows during the winter; (2) dampening of the diurnal variation in air temperature and absolute humidity from the spring to the autumn; (3) lower photosynthetically active radiation and a lower direct:diffuse under the panels; and (4) reduced wind speed between the panel rows and substantially reduced wind speeds under the panels. Further, there were differences in vegetation type and productivity and greenhouse gas emissions. Given the centrality of climate on ecosystem function, quantifying the microclimatic impacts of this emerging land use change is critical. We anticipate these data will help develop understanding of effects in other climates, under different solar park designs and the implications for the function and service provision of the hosting landscape.

  20. Vegetation and other development options for mitigating urban air pollution impacts

    EPA Science Inventory

    In addition to installing air pollution control devices and reducing emissions activities, urban air pollution can be further mitigated through planning and design strategies including vegetation planting, building design, installing roadside and near source structures, and modif...

  1. Reflectance of vegetation, soil, and water. [in Hidalgo County, Texas

    NASA Technical Reports Server (NTRS)

    Wiegand, C. L. (Principal Investigator)

    1973-01-01

    The author has identified the following significant results. A study was conducted in a 340-acre (139 hectares) field of grain sorghum (Sorghum bicolor (L.) Moench) to determine if multispectral data from ERTS-1 could be used to detect differences in chlorophyll concentration between iron-deficient (chlorotic) and apparently normal (green) grain sorghum. Chlorotic sorghum areas 2.8 acres (1.1 hectares) or larger in size were identified on a computer printout of band 5 data which contains the chlorophyll absorption band at the 0.65 micron wavelength. ERTS resolution is sufficient for practical applications in detecting iron-deficient sorghum in otherwise uniform fields. The first classification map of the study county has been produced. Vegetation (crops), rangeland, bare soil, water, and an undefined (all other) category occupied 15.2, 45.0, 19.1, 0.02, and 20.6% of the land area, respectively.

  2. Soil, water, and vegetation conditions in south Texas

    NASA Technical Reports Server (NTRS)

    Wiegand, C. L.; Gausman, H. W.; Leamer, R. W.; Richardson, A. J.; Everitt, J. H.; Gerbermann, A. H. (Principal Investigator)

    1976-01-01

    The author has identified the following significant results. Field spectral measurements and laboratory densitometric measurements showed that tree canopy reflectance differences among the Marrs, Redblush, and Valencia varieties in the visible spectral region were due to their different leaf chlorophyll concentrations. Field measurements of visible light reflectance were directly related to the tonal responses on infrared color photos of the varietal tree canopies. Consequently, densitometric measurements of the foliage on the infrared color transparency with red-filtered light successfully discriminated among the three varieties. Reflectance measurements with a field spectroradiometer on nine dates the growing season of two wheat varieties, Milam and Penjamo, documented their spectra over the 0.45 to 2.50 micron wavelength interval associated with plant cover and physiological development. An image analyzer system was used to optically planimeter the percentage of soil background, vegetation and shadow in the vertical photographs taken within the FOV of the spectroradiometer on each measurement date.

  3. Importance of Soil Moisture and Vegetation Cover for Energy Balance partition in Burkina Faso

    NASA Astrophysics Data System (ADS)

    Ceperley, N. C.; Mande, T.; Tyler, S. W.; Bou-Zeid, E.; Van De Giesen, N.; Parlange, M. B.

    2015-12-01

    Land surface characteristics are the main control on hydrologic processes, the driver of most livelihoods, in semi arid West Africa. We use the energy and water balance measured with two eddy-covariance towers, coupled with a dense network of small, wireless meteorological stations in a small (3.5 km2) catchment to understand these relationships. Time series of monthly averages of soil moisture, rainfall, air temperature, cloud cover, components of net radiation, wind speed, and NDVI are presented in relation to the evaporative fraction and energy balance. We found that both latent and sensible heat fluxes are greater over mixed forest and savanna areas compared agricultural land. Sensible heat is found to be most different between the two land-covers at the end of the year, when the grass and vegetation is dry, and latent heat is found to be most different at the beginning of the year, when bare ground dominates. Further examination shows that soil moisture and vegetation indexes provide the main controls on evaporative fraction. These findings have implications for modeling the evaporation over large regions based on remotely sensed land surface temperature. The site is characteristic of the contrasts in vegetation and moisture availability present in the rocky escarpments found in Northern Benin and Southeastern Burkina Faso. Historically these sites are important in location for village choice and land use designation. These findings reinforce local cultural beliefs of the importance of vegetation for climate regulation and may provide support to local farmers for improving the resilience of natural resources and livelihood security.

  4. [Concentrations of mercury in ambient air in wastewater irrigated area of Tianjin City and its accumulation in leafy vegetables].

    PubMed

    Zheng, Shun-An; Han, Yun-Lei; Zheng, Xiang-Qun

    2014-11-01

    limit of mercury in food. Spinach appeared to accumulate more mercury than the other four vegetables, in which the median and mean mercury content were both higher than 20 μg x kg(-1). The mercury concentrations in rape, lettuce and allium tuberosum were lower than the standard. Moreover, test results indicated that the Hg content in leafy vegetables was mainly the gaseous mercury through leaf adsorption but not the Hg particulates. This study clearly manifested that there should be a great concern on the pollution risk of both air-and soil borne mercury when cultivating leafy vegetables in long-term wastewater-irrigated area.

  5. Antibiotic resistance genes in manure-amended soil and vegetables at harvest.

    PubMed

    Wang, Feng-Hua; Qiao, Min; Chen, Zheng; Su, Jian-Qiang; Zhu, Yong-Guan

    2015-12-15

    Lettuce and endive, which can be eaten raw, were planted on the manure-amended soil in order to explore the influence of plants on the abundance of antibiotic resistance genes (ARGs) in bulk soil and rhizosphere soil, and the occurrence of ARGs on harvested vegetables. Twelve ARGs and one integrase gene (intI1) were detected in all soil samples. Five ARGs (sulI, tetG, tetC, tetA, and tetM) showed lower abundance in the soil with plants than those without. ARGs and intI1 gene were also detected on harvested vegetables grown in manure-amended soil, including endophytes and phyllosphere microorganisms. The results demonstrated that planting had an effect on the distribution of ARGs in manure-amended soil, and ARGs were detected on harvested vegetables after growing in manure-amended soil, which had potential threat to human health.

  6. Response of spectral vegetation indices to soil moisture in grasslands and shrublands

    USGS Publications Warehouse

    Zhang, Li; Ji, Lei; Wylie, Bruce K.

    2011-01-01

    The relationships between satellite-derived vegetation indices (VIs) and soil moisture are complicated because of the time lag of the vegetation response to soil moisture. In this study, we used a distributed lag regression model to evaluate the lag responses of VIs to soil moisture for grasslands and shrublands at Soil Climate Analysis Network sites in the central and western United States. We examined the relationships between Moderate Resolution Imaging Spectroradiometer (MODIS)-derived VIs and soil moisture measurements. The Normalized Difference Vegetation Index (NDVI) and Normalized Difference Water Index (NDWI) showed significant lag responses to soil moisture. The lag length varies from 8 to 56 days for NDVI and from 16 to 56 days for NDWI. However, the lag response of NDVI and NDWI to soil moisture varied among the sites. Our study suggests that the lag effect needs to be taken into consideration when the VIs are used to estimate soil moisture.

  7. Modeling radium and radon transport through soil and vegetation

    USGS Publications Warehouse

    Kozak, J.A.; Reeves, H.W.; Lewis, B.A.

    2003-01-01

    A one-dimensional flow and transport model was developed to describe the movement of two fluid phases, gas and water, within a porous medium and the transport of 226Ra and 222Rn within and between these two phases. Included in this model is the vegetative uptake of water and aqueous 226Ra and 222Rn that can be extracted from the soil via the transpiration stream. The mathematical model is formulated through a set of phase balance equations and a set of species balance equations. Mass exchange, sink terms and the dependence of physical properties upon phase composition couple the two sets of equations. Numerical solution of each set, with iteration between the sets, is carried out leading to a set-iterative compositional model. The Petrov-Galerkin finite element approach is used to allow for upstream weighting if required for a given simulation. Mass lumping improves solution convergence and stability behavior. The resulting numerical model was applied to four problems and was found to produce accurate, mass conservative solutions when compared to published experimental and numerical results and theoretical column experiments. Preliminary results suggest that the model can be used as an investigative tool to determine the feasibility of phytoremediating radium and radon-contaminated soil. ?? 2003 Elsevier Science B.V. All rights reserved.

  8. A multi-frequency radiometric measurement of soil moisture content over bare and vegetated fields

    NASA Technical Reports Server (NTRS)

    Wang, J. R.; Schmugge, T. J.; Mcmurtrey, J. E., III; Gould, W. I.; Glazar, W. S.; Fuchs, J. E. (Principal Investigator)

    1981-01-01

    A USDA Beltsville Agricultural Research Center site was used for an experiment in which soil moisture remote sensing over bare, grass, and alfalfa fields was conducted over a three-month period using 0.6 GHz, 1.4 GHz, and 10.6 GHz Dicke-type microwave radiometers mounted on mobile towers. Ground truth soil moisture content and ambient air and sil temperatures were obtained concurrently with the radiometric measurements. Biomass of the vegetation cover was sampled about once a week. Soil density for each of the three fields was measured several times during the course of the experiment. Results of the radiometric masurements confirm the frequency dependence of moisture sensing sensitivity reduction reported earlier. Observations over the bare, wet field show that the measured brightness temperature is lowest at 5.0 GHz and highest of 0.6 GHz frequency, a result contrary to expectation based on the estimated dielectric permittivity of soil water mixtures and current radiative transfer model in that frequency range.

  9. Representing the effects of alpine grassland vegetation cover on the simulation of soil thermal dynamics by ecosystem models applied to the Qinghai-Tibetan Plateau

    USGS Publications Warehouse

    Yi, S.; Li, N.; Xiang, B.; Wang, X.; Ye, B.; McGuire, A.D.

    2013-01-01

    Soil surface temperature is a critical boundary condition for the simulation of soil temperature by environmental models. It is influenced by atmospheric and soil conditions and by vegetation cover. In sophisticated land surface models, it is simulated iteratively by solving surface energy budget equations. In ecosystem, permafrost, and hydrology models, the consideration of soil surface temperature is generally simple. In this study, we developed a methodology for representing the effects of vegetation cover and atmospheric factors on the estimation of soil surface temperature for alpine grassland ecosystems on the Qinghai-Tibetan Plateau. Our approach integrated measurements from meteorological stations with simulations from a sophisticated land surface model to develop an equation set for estimating soil surface temperature. After implementing this equation set into an ecosystem model and evaluating the performance of the ecosystem model in simulating soil temperature at different depths in the soil profile, we applied the model to simulate interactions among vegetation cover, freeze-thaw cycles, and soil erosion to demonstrate potential applications made possible through the implementation of the methodology developed in this study. Results showed that (1) to properly estimate daily soil surface temperature, algorithms should use air temperature, downward solar radiation, and vegetation cover as independent variables; (2) the equation set developed in this study performed better than soil surface temperature algorithms used in other models; and (3) the ecosystem model performed well in simulating soil temperature throughout the soil profile using the equation set developed in this study. Our application of the model indicates that the representation in ecosystem models of the effects of vegetation cover on the simulation of soil thermal dynamics has the potential to substantially improve our understanding of the vulnerability of alpine grassland ecosystems to

  10. Evaluation of Landsat Multispectral Scanner data for mapping vegetated soil landscapes

    USGS Publications Warehouse

    Thompson, D. R.; Haas, Robert H.; Milford, M. H.

    1981-01-01

    Landsat multispectral scanner data for Brazos County, Texas, were evaluated in terms of effectiveness for classifying soils on vegetated landscapes at three times during the year: a time of normally adequate soil water, a time of expected soil water deficit, and a time when soil water is normally being replenished. Six test sites were used to evaluate LARSYS supervised and unsupervised classification of vegetated soil landscapes. Open grassland soils were best separated in the fall during a period when soil moisture was being replenished after the summer period of soil water deficit. Woodland soils were separated by Landsat data in late spring when adequate moisture was available. However, a high degree of accuracy was not achieved using Landsat for separating soil map units. Accurate separation of soil mapping units on vegetated landscapes was not possible during late summer when soil water was deficient. Selected soil properties important to plant growth were separable on the test sites using June and October Landsat data. Particle size and soil moisture regime were separated at both dates. Soils with argillic horizons were separated from soils without argillic horizons.

  11. Accumulation of Heavy Metals in Vegetable Species Planted in Contaminated Soils and the Health Risk Assessment

    PubMed Central

    Zhou, Hang; Yang, Wen-Tao; Zhou, Xin; Liu, Li; Gu, Jiao-Feng; Wang, Wen-Lei; Zou, Jia-Ling; Tian, Tao; Peng, Pei-Qin; Liao, Bo-Han

    2016-01-01

    The objectives of the present study were to investigate heavy metal accumulation in 22 vegetable species and to assess the human health risks of vegetable consumption. Six vegetable types were cultivated on farmland contaminated with heavy metals (Pb, Cd, Cu, Zn, and As). The target hazard quotient (THQ) method was used to assess the human health risks posed by heavy metals through vegetable consumption. Clear differences were found in the concentrations of heavy metals in edible parts of the different vegetables. The concentrations of heavy metals decreased in the sequence as leafy vegetables > stalk vegetables/root vegetables/solanaceous vegetables > legume vegetables/melon vegetables. The ability of leafy vegetables to uptake and accumulate heavy metals was the highest, and that of melon vegetables was the lowest. This indicated that the low accumulators (melon vegetables) were suitable for being planted on contaminated soil, while the high accumulators (leafy vegetables) were unsuitable. In Shizhuyuan area, China, the total THQ values of adults and children through consumption of vegetables were 4.12 and 5.41, respectively, suggesting that the residents may be facing health risks due to vegetable consumption, and that children were vulnerable to the adverse effects of heavy metal ingestion. PMID:26959043

  12. Accumulation of Heavy Metals in Vegetable Species Planted in Contaminated Soils and the Health Risk Assessment.

    PubMed

    Zhou, Hang; Yang, Wen-Tao; Zhou, Xin; Liu, Li; Gu, Jiao-Feng; Wang, Wen-Lei; Zou, Jia-Ling; Tian, Tao; Peng, Pei-Qin; Liao, Bo-Han

    2016-03-04

    The objectives of the present study were to investigate heavy metal accumulation in 22 vegetable species and to assess the human health risks of vegetable consumption. Six vegetable types were cultivated on farmland contaminated with heavy metals (Pb, Cd, Cu, Zn, and As). The target hazard quotient (THQ) method was used to assess the human health risks posed by heavy metals through vegetable consumption. Clear differences were found in the concentrations of heavy metals in edible parts of the different vegetables. The concentrations of heavy metals decreased in the sequence as leafy vegetables > stalk vegetables/root vegetables/solanaceous vegetables > legume vegetables/melon vegetables. The ability of leafy vegetables to uptake and accumulate heavy metals was the highest, and that of melon vegetables was the lowest. This indicated that the low accumulators (melon vegetables) were suitable for being planted on contaminated soil, while the high accumulators (leafy vegetables) were unsuitable. In Shizhuyuan area, China, the total THQ values of adults and children through consumption of vegetables were 4.12 and 5.41, respectively, suggesting that the residents may be facing health risks due to vegetable consumption, and that children were vulnerable to the adverse effects of heavy metal ingestion.

  13. Radar backscattering measurement of bare soil and vegetation covered soil using X-band and full polarization

    NASA Astrophysics Data System (ADS)

    Goswami, B.; Kalita, M.

    2014-11-01

    The objective of the study is to measure backscattered power of bare soil and vegetation covered soil using X-band scatterometer system with full polarization and various angles during monsoon season and relate backscattered power to the density of vegetation over soil. The measurement was conducted at an experimental field located in the campus of Assam Engineering College, Guwahati, India. The soil sample consists of Silt and Clay in higher proportions as compared to Sand. The scatterometer system consists of dual-polarimetric square horn antennas, Power meter, Klystron, coaxial cables, isolator and waveguide detector. The polarization of the horn antennas as well as the look angle can be changed in the set-up. The backscattering coefficients were calculated by applying a radar equation for the measured values at incident angles between 30° and 60° for full polarization (HH, VV, HV, VH), respectively, and compared with vegetation cover over soil for each scatterometer measurement simultaneously. The VH polarization and 60° look angle are found to be the most suitable combination of configuration of an X-band scatterometer for distinguishing the land cover targets such as bare soil and vegetation covered soil. From the analysis of the results, polarimetric scatterometer data appear to be promising to distinguish the land cover types such as bare soil and soil completely covered by vegetation. The results of this study will help the scientists working in the field of active microwave remote sensing.

  14. Impacts of grassland types and vegetation cover changes on surface air temperature in the regions of temperate grassland of China

    NASA Astrophysics Data System (ADS)

    Shen, Xiangjin; Liu, Binhui; Li, Guangdi; Yu, Pujia; Zhou, Daowei

    2016-10-01

    The sensitivity of surface air temperature response to different grassland types and vegetation cover changes in the regions of temperate grassland of China was analyzed by observation minus reanalysis (OMR) method. The basis of the OMR approach is that reanalysis data are insensitive to local surface properties, so the temperature differences between surface observations and reanalysis can be attributed to land effects. Results showed that growing-season air temperature increased by 0.592 °C/decade in the regions of temperate grassland of China, with about 31 % of observed warming associated with the effects of grassland types and vegetation cover changes. For different grassland types, the growing-season OMR trend was the strongest for temperate desert steppe (0.259 °C/decade) and the weakest for temperate meadow (0.114 °C/decade). Our results suggest that the stronger intraseasonal changes of grassland vegetation are present, the more sensitive the OMR trend responds to the intraseasonal vegetation cover changes. In August and September, the OMR of temperate meadow showed a weak cooling trend. For temperate meadow, about 72.2 and 72.6 % of surface cooling were explained by both grassland type and increase of vegetation cover for August and September, respectively. For temperate steppe and temperate desert steppe, due to the limited soil moisture and little evaporative cooling feedback, the vegetation changes have no significant effect on the surface air temperature. These results indicate that the impact of grassland types and vegetation cover changes should be considered when projecting further climate change in the temperate grassland region of China.

  15. Assessing the effect of vegetation in the estimation of soil properties with field VNIR radiometry

    NASA Astrophysics Data System (ADS)

    Melendez-Pastor, I.; Córdoba-Sola, P.; Navarro-Pedreño, J.; Gómez, I.; Koch, M.

    2009-04-01

    Spectroradiometric soil surveys (field radiometry) are a valuable technique for soil classification and properties estimation. Field radiometry combines -in a relatively easy-to-use procedure- a fast, accurate and non-destructive sampling method. A wide range of soil properties have been quantitatively estimated with field or laboratory radiometry. In addition, field radiometry is a basic stage in remote sensing studies. It allows the up-scaling process of soil, vegetation or water parameters from the ground level to the airborne or spaceborne sensors level. Field radiometry plays a crucial role in training and validation stages of quantitative remote sensing. A complex problem in remote sensing appears when several components are mixed within a pixel and the resulting pixel's spectrum is a combination of the individual components. This work assess the effect of vegetation in soil properties estimation with linear regression models. Field spectra were taken from soil-vegetation mixtures under natural illumination with a portable spectroradiometer in the visible and near-infrared (VNIR) spectral range. Soil and vegetation samples for each radiometric sampling point were taken and analyzed in laboratory. Soil moisture content and soil organic carbon measured by the LOI (Loss-On-Ignition) method (Konen et al. 2002) were used in this approach. A derivative analysis of field spectra was used to determine the position and magnitude of absorption bands according to the method employed by Melendez-Pastor et al. (2008). Pearson correlations between soil parameters and each spectral band were computed and correlograms for the first and second derivate were obtained. Maximum (approximates to +1) and minimum (approximates to -1) Pearson correlations were used to normalize correlograms between 0 to 1. High relatively correlated bands (with values ranging from 0 to 0.1 or from 0-9 to 1 for the normalized correlograms) were identified and used as explicative variables in the

  16. Effects of vegetation types on soil moisture estimation from the normalized land surface temperature versus vegetation index space

    NASA Astrophysics Data System (ADS)

    Zhang, Dianjun; Zhou, Guoqing

    2015-12-01

    Soil moisture (SM) is a key variable that has been widely used in many environmental studies. Land surface temperature versus vegetation index (LST-VI) space becomes a common way to estimate SM in optical remote sensing applications. Normalized LST-VI space is established by the normalized LST and VI to obtain the comparable SM in Zhang et al. (Validation of a practical normalized soil moisture model with in situ measurements in humid and semiarid regions [J]. International Journal of Remote Sensing, DOI: 10.1080/01431161.2015.1055610). The boundary conditions in the study were set to limit the point A (the driest bare soil) and B (the wettest bare soil) for surface energy closure. However, no limitation was installed for point D (the full vegetation cover). In this paper, many vegetation types are simulated by the land surface model - Noah LSM 3.2 to analyze the effects on soil moisture estimation, such as crop, grass and mixed forest. The locations of point D are changed with vegetation types. The normalized LST of point D for forest is much lower than crop and grass. The location of point D is basically unchanged for crop and grass.

  17. Soils and vegetation of Santa Barbara Island, Channel Islands National Park, California, USA

    NASA Astrophysics Data System (ADS)

    Halvorson, William L.; Fenn, Dennis B.; Allardice, William R.

    1988-01-01

    The multifaceted development of an erosion surface on Santa Barbara Island, Channel Islands National Park, California, has led to this study of the relationship between soils and vegetation. A dry Mediterranean climate and past attempts at farming and introductions of alien species have led to vegetative degradation accompanied by both gully and surface erosion. Soil and vegetation analyses show this erosion to be in a location of transition. The soils are Typic Chromoxererts (Vertisol Order) with high clay, salinity, and sodium contents. The vegetation is ecotonal in nature, grading from a principally alien annual grassland with Avena fatua and Atriplex semibaccata to a shrub community dominated by the native Suaeda californica. Management toward revegetation and stabilization of this island ecosystem will be difficult with high clay, saline-sodic soils and disturbed vegetation.

  18. Soil detachment by overland flow under different vegetation restoration models in the loess plateau of China

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Land use change has significant effects on soil properties and vegetation cover and thus probably affects soil detachment by overland flow. Few studies were conducted to evaluate the effect of restoration models on the soil detachment process in the Loess Plateau in the past decade during which a Gr...

  19. Community structure analysis of soil ammonia oxidizers during vegetation restoration in southwest China.

    PubMed

    Liang, Yueming; He, Xunyang; Liang, Shichu; Zhang, Wei; Chen, Xiangbi; Feng, Shuzheng; Su, Yirong

    2014-03-01

    Soil ammonia oxidizers play a critical role in nitrogen cycling and ecological restoration. The composition and structure of soil ammonia oxidizers and their impacting factors were studied in four typical ecosystem soils, tussock (T), shrub (S), secondary forest (SF), and primary forest (PF), during vegetation restoration in the Karst region of Southwest China. The composition and structure of the ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) communities were characterized by sequencing the amoA and arch-amoA genes, respectively. The diversity of soil ammonia oxidizers (except in S) and plant Shannon diversity index gradually increased with vegetation restoration, and the ammonia oxidizer communities differed significantly (p < 0.001). Amplicons of AOA from the Nitrososphaera cluster dominated all four ecosystem soils. AOB Nitrosospira cluster 3b only appeared in PF and SF soils, while Nitrosospira cluster 3a species were found in all soils. Changes in AOB paralleled the changes in soil ammonium content that occurred with vegetation restoration. Redundancy analysis showed that the distribution of dominant AOB species was linked to pH, soil urease activity, and soil C/N ratio, whereas the distribution of dominant AOA species was mainly influenced by litter nitrogen content and C/N ratio. These results suggested that the composition and structure of the AOB community were more sensitive to changes in vegetation and soil ammonium content, and may be an important indicator of nitrogen availability in Karst ecosystem soils.

  20. Derivation of soil moisture retrieval uncertainties associated to the simplification of the dynamic vegetation signal.

    NASA Astrophysics Data System (ADS)

    Vreugdenhil, Mariette; Dorigo, Wouter; de Jeu, Richard; Hahn, Sebastian; Salinas, Jose Luis; Wagner, Wolfgang

    2014-05-01

    Satellite-based microwave remote sensing has proven to provide reliable soil moisture observations on a global scale over the last decades. In microwave remote sensing of soil moisture the satellite signal holds information on both soil moisture and vegetation. Separating these components from each other is not straightforward. In the last years the importance of a robust and reliable vegetation parameterization within the soil moisture retrieval algorithms has become evident. In the TU-Wien soil moisture retrieval algorithm, developed by the Vienna University of Technology, the backscatter observations are corrected for vegetation effects by way of the slope and curvature. The slope and curvature are derivates of noisy backscatter measurements in relation to incidence angle and hence have a high level of noise. Therefore, they are averaged over several years resulting in a fixed seasonal vegetation correction, where no inter-annual variability is present in the characterisation of vegetation. This study assesses the strengths and weaknesses of the fixed seasonal vegetation correction in the TU-Wien soil moisture retrieval algorithm. The Vegetation Optical Depth (VOD) retrieved from AMSR-E passive microwave observations with the VUA-NASA retrieval algorithm is analysed to identify regions with high inter-annual variability in vegetation. For these regions the effect of a fixed seasonal correction on the soil moisture retrieval is investigated. First, the TU-Wien soil moisture products before and after the application of the vegetation correction, the TU-Wien normalised backscatter and TU-Wien soil moisture respectively, are compared to modelled soil moisture from ECMWFs ERA-Interim. With this analysis regions where the vegetation correction decreases the quality of the TU-Wien soil moisture product with regard to modeled soil moisture can be identified. Secondly, the vegetation correction within the TU-Wien retrieval algorithm is replaced by the VOD to simulate an

  1. Dual frequency microwave radiometer measurements of soil moisture for bare and vegetated rough surfaces

    NASA Technical Reports Server (NTRS)

    Lee, S. L.

    1974-01-01

    Controlled ground-based passive microwave radiometric measurements on soil moisture were conducted to determine the effects of terrain surface roughness and vegetation on microwave emission. Theoretical predictions were compared with the experimental results and with some recent airborne radiometric measurements. The relationship of soil moisture to the permittivity for the soil was obtained in the laboratory. A dual frequency radiometer, 1.41356 GHz and 10.69 GHz, took measurements at angles between 0 and 50 degrees from an altitude of about fifty feet. Distinct surface roughnesses were studied. With the roughness undisturbed, oats were later planted and vegetated and bare field measurements were compared. The 1.4 GHz radiometer was less affected than the 10.6 GHz radiometer, which under vegetated conditions was incapable of detecting soil moisture. The bare surface theoretical model was inadequate, although the vegetation model appeared to be valid. Moisture parameters to correlate apparent temperature with soil moisture were compared.

  2. Evaluation of MODIS NDVI and NDWI for vegetation drought monitoring using Oklahoma Mesonet soil moisture data

    USGS Publications Warehouse

    Gu, Y.; Hunt, E.; Wardlow, B.; Basara, J.B.; Brown, J.F.; Verdin, J.P.

    2008-01-01

    The evaluation of the relationship between satellite-derived vegetation indices (normalized difference vegetation index and normalized difference water index) and soil moisture improves our understanding of how these indices respond to soil moisture fluctuations. Soil moisture deficits are ultimately tied to drought stress on plants. The diverse terrain and climate of Oklahoma, the extensive soil moisture network of the Oklahoma Mesonet, and satellite-derived indices from the Moderate Resolution Imaging Spectroradiometer (MODIS) provided an opportunity to study correlations between soil moisture and vegetation indices over the 2002-2006 growing seasons. Results showed that the correlation between both indices and the fractional water index (FWI) was highly dependent on land cover heterogeneity and soil type. Sites surrounded by relatively homogeneous vegetation cover with silt loam soils had the highest correlation between the FWI and both vegetation-related indices (r???0.73), while sites with heterogeneous vegetation cover and loam soils had the lowest correlation (r???0.22). Copyright 2008 by the American Geophysical Union.

  3. Integrated analysis of climate, soil, topography and vegetative growth in Iberian viticultural regions.

    PubMed

    Fraga, Helder; Malheiro, Aureliano C; Moutinho-Pereira, José; Cardoso, Rita M; Soares, Pedro M M; Cancela, Javier J; Pinto, Joaquim G; Santos, João A

    2014-01-01

    The Iberian viticultural regions are convened according to the Denomination of Origin (DO) and present different climates, soils, topography and management practices. All these elements influence the vegetative growth of different varieties throughout the peninsula, and are tied to grape quality and wine type. In the current study, an integrated analysis of climate, soil, topography and vegetative growth was performed for the Iberian DO regions, using state-of-the-art datasets. For climatic assessment, a categorized index, accounting for phenological/thermal development, water availability and grape ripening conditions was computed. Soil textural classes were established to distinguish soil types. Elevation and aspect (orientation) were also taken into account, as the leading topographic elements. A spectral vegetation index was used to assess grapevine vegetative growth and an integrated analysis of all variables was performed. The results showed that the integrated climate-soil-topography influence on vine performance is evident. Most Iberian vineyards are grown in temperate dry climates with loamy soils, presenting low vegetative growth. Vineyards in temperate humid conditions tend to show higher vegetative growth. Conversely, in cooler/warmer climates, lower vigour vineyards prevail and other factors, such as soil type and precipitation acquire more important roles in driving vigour. Vines in prevailing loamy soils are grown over a wide climatic diversity, suggesting that precipitation is the primary factor influencing vigour. The present assessment of terroir characteristics allows direct comparison among wine regions and may have great value to viticulturists, particularly under a changing climate.

  4. Integrated Analysis of Climate, Soil, Topography and Vegetative Growth in Iberian Viticultural Regions

    PubMed Central

    Fraga, Helder; Malheiro, Aureliano C.; Moutinho-Pereira, José; Cardoso, Rita M.; Soares, Pedro M. M.; Cancela, Javier J.; Pinto, Joaquim G.; Santos, João A.

    2014-01-01

    The Iberian viticultural regions are convened according to the Denomination of Origin (DO) and present different climates, soils, topography and management practices. All these elements influence the vegetative growth of different varieties throughout the peninsula, and are tied to grape quality and wine type. In the current study, an integrated analysis of climate, soil, topography and vegetative growth was performed for the Iberian DO regions, using state-of-the-art datasets. For climatic assessment, a categorized index, accounting for phenological/thermal development, water availability and grape ripening conditions was computed. Soil textural classes were established to distinguish soil types. Elevation and aspect (orientation) were also taken into account, as the leading topographic elements. A spectral vegetation index was used to assess grapevine vegetative growth and an integrated analysis of all variables was performed. The results showed that the integrated climate-soil-topography influence on vine performance is evident. Most Iberian vineyards are grown in temperate dry climates with loamy soils, presenting low vegetative growth. Vineyards in temperate humid conditions tend to show higher vegetative growth. Conversely, in cooler/warmer climates, lower vigour vineyards prevail and other factors, such as soil type and precipitation acquire more important roles in driving vigour. Vines in prevailing loamy soils are grown over a wide climatic diversity, suggesting that precipitation is the primary factor influencing vigour. The present assessment of terroir characteristics allows direct comparison among wine regions and may have great value to viticulturists, particularly under a changing climate. PMID:25251495

  5. Integrated Analysis of Climate, Soil, Topography and Vegetative Growth in Iberian Viticultural Regions

    NASA Astrophysics Data System (ADS)

    Fraga, Helder; Malheiro, Aureliano C.; Moutinho-Pereira, José; Cardoso, Rita M.; Soares, Pedro M. M.; Cancela, Javier J.; Pinto, Joaquim G.; Santos, João A.

    2015-04-01

    The Iberian viticultural regions are convened according to the Denomination of Origin (DO) and present different climates, soils, topography and management practices. All these elements influence the vegetative growth of different varieties throughout the peninsula, and are tied to grape quality and wine type. In the current study, an integrated analysis of climate, soil, topography and vegetative growth was performed for the Iberian DO regions, using state-of-the-art datasets. For climatic assessment, a categorized index, accounting for phenological/thermal development, water availability and grape ripening conditions was computed. Soil textural classes were established to distinguish soil types. Elevation and aspect (orientation) were also taken into account, as the leading topographic elements. A spectral vegetation index was used to assess grapevine vegetative growth and an integrated analysis of all variables was performed. The results showed that the integrated climate-soil-topography influence on vine performance is evident. Most Iberian vineyards are grown in temperate dry climates with loamy soils, presenting low vegetative growth. Vineyards in temperate humid conditions tend to show higher vegetative growth. Conversely, in cooler/warmer climates, lower vigour vineyards prevail and other factors, such as soil type and precipitation acquire more important roles in driving vigour. Vines in prevailing loamy soils are grown over a wide climatic diversity, suggesting that precipitation is the primary factor influencing vigour. The present assessment of terroir characteristics allows direct comparison among wine regions and may have great value to viticulturists, particularly under a changing climate.

  6. The Effect of Vegetation on Soil Moisture Retrievals from GPS Signal-to-Noise Ratio Data

    NASA Astrophysics Data System (ADS)

    Chew, C. C.; Small, E. E.; Larson, K. M.; Zavorotny, V.

    2012-12-01

    GPS-Interferometric Reflectometry (GPS-IR) is a method of environmental monitoring that relates changes in ground-reflected (multipath) GPS signals to changes in surface soil moisture and vegetative state for an area of approximately 1000 m2 surrounding a GPS antenna. GPS-IR operates as a bi-static radar: L2C frequency signals transmitted by GPS satellites and subsequent reflections (multipath) are measured by antennas at permanent GPS stations. Changes in multipath signals are seen in signal-to-noise ratio (SNR) interferograms, which are recorded by the GPS receiver. Results from previous field studies have shown that shallow soil moisture can be estimated from SNR phase for bare soil conditions or when vegetation is sparse. Vegetation surrounding a GPS antenna affects the phase shift, amplitude, and frequency/apparent reflector height of SNR oscillations. Therefore, it is necessary to quantify the vegetation conditions, for example vegetation height or water content, that preclude retrieval of soil moisture estimates using GPS-IR. We use both field data and an electrodynamic model that simulates SNR interferograms for variable soil and vegetation conditions to: 1. Determine how changes in vegetation height, biomass, and water content affect GPS phase, amplitude, and apparent reflector height and 2. Quantify the amount of vegetation that obscures the soil moisture signal in SNR data. We report results for rangeland and agricultural sites. At the rangeland sites, vegetation water content only varies between 0 and 0.6 kg/m2. Both observed and simulated SNR data from these sites show that apparent reflector height is nearly constant. Therefore, SNR interferograms are strongly affected by permittivity at the soil surface, and thus soil moisture can be retrieved. Even though reflector height does not change, SNR phase shift and amplitude are affected by fluctuations in rangeland vegetation and must be accounted for in soil moisture retrievals. At several agricultural

  7. Modeling the Effect of Vegetation on Passive Microwave Remote Sensing of Soil Moisture

    NASA Technical Reports Server (NTRS)

    Liu, Y. P.; Inguva, R.; Crosson, W. L.; Coleman, T. L.; Laymon, C.; Fahsi, A.

    1998-01-01

    The effect of vegetation on passive microwave remote sensing of soil moisture is studied. The radiative transfer modeling work of Njoku and Kong is applied to a stratified medium of which the upper layer is treated as a layer of vegetation. An effective dielectric constant for this vegetation layer is computed using estimates of the dielectric constant of individual components of the vegetation layer. The horizontally-polarized brightness temperature is then computed as a function of the incidence angle. Model predictions are used to compare with the data obtained in the Huntsville '96, remote sensing of soil moisture experiment, and with predictions obtained using a correction procedure of Jackson and Schmugge.

  8. Modeling soil water content for vegetation modeling improvement

    NASA Astrophysics Data System (ADS)

    Cianfrani, Carmen; Buri, Aline; Zingg, Barbara; Vittoz, Pascal; Verrecchia, Eric; Guisan, Antoine

    2016-04-01

    Soil water content (SWC) is known to be important for plants as it affects the physiological processes regulating plant growth. Therefore, SWC controls plant distribution over the Earth surface, ranging from deserts and grassland to rain forests. Unfortunately, only a few data on SWC are available as its measurement is very time consuming and costly and needs specific laboratory tools. The scarcity of SWC measurements in geographic space makes it difficult to model and spatially project SWC over larger areas. In particular, it prevents its inclusion in plant species distribution model (SDMs) as predictor. The aims of this study were, first, to test a new methodology allowing problems of the scarcity of SWC measurements to be overpassed and second, to model and spatially project SWC in order to improve plant SDMs with the inclusion of SWC parameter. The study was developed in four steps. First, SWC was modeled by measuring it at 10 different pressures (expressed in pF and ranging from pF=0 to pF=4.2). The different pF represent different degrees of soil water availability for plants. An ensemble of bivariate models was built to overpass the problem of having only a few SWC measurements (n = 24) but several predictors to include in the model. Soil texture (clay, silt, sand), organic matter (OM), topographic variables (elevation, aspect, convexity), climatic variables (precipitation) and hydrological variables (river distance, NDWI) were used as predictors. Weighted ensemble models were built using only bivariate models with adjusted-R2 > 0.5 for each SWC at different pF. The second step consisted in running plant SDMs including modeled SWC jointly with the conventional topo-climatic variable used for plant SDMs. Third, SDMs were only run using the conventional topo-climatic variables. Finally, comparing the models obtained in the second and third steps allowed assessing the additional predictive power of SWC in plant SDMs. SWC ensemble models remained very good, with

  9. Individual contributions of climate and vegetation change to soil moisture trends across multiple spatial scales

    PubMed Central

    Feng, Huihui

    2016-01-01

    Climate and vegetation change are two dominating factors for soil moisture trend. However, their individual contributions remain unknown due to their complex interaction. Here, I separated their contributions through a trajectory-based method across the global, regional and local scales. Our results demonstrated that climate change accounted for 98.78% and 114.64% of the global drying and wetting trend. Vegetation change exhibited a relatively weak influence (contributing 1.22% and −14.64% of the global drying and wetting) because it occurred in a limited area on land. Regionally, the impact of vegetation change cannot be neglected, which contributed −40.21% of the soil moisture change in the wetting zone. Locally, the contributions strongly correlated to the local environmental characteristics. Vegetation negatively affected soil moisture trends in the dry and sparsely vegetated regions and positively in the wet and densely vegetated regions. I conclude that individual contributions of climate and vegetation change vary at the global, regional and local scales. Climate change dominates the soil moisture trends, while vegetation change acts as a regulator to drying or wetting the soil under the changing climate. PMID:27600157

  10. Using GPS Interferometric Reflectometry to estimate soil moisture and vegetation water content fluctuations

    NASA Astrophysics Data System (ADS)

    Chew, C. C.; Small, E. E.; Larson, K. M.; Braun, J. J.; Shreve, C. M.

    2010-12-01

    High-precision GPS receivers can be used to estimate fluctuations in near surface soil moisture, snow and vegetation water content. This approach, referred to as GPS-Interferometric Reflectometry (GPS-IR), relates precise changes in the geometry of reflected GPS signals to observe soil moisture and snow while simultaneously using signal attenuation and diffuse scattering to infer changes in vegetative state. Previous remote sensing research has shown that microwave signals (e.g., L-band) are optimal for measuring hydrologic variables, such as soil moisture, and because GPS satellites transmit similar signals, they can be useful for sensing water in the environment. In addition, standard GPS antenna configurations that are used in NSF's Plate Boundary Observatory network yield sensing footprints of ~1000 m2. Given this sensitivity, hundreds of GPS receivers that exist in the U.S. could be used to provide near-real time estimates of soil moisture and vegetation water content for satellite validation, drought monitoring and related studies. A significant obstacle to using L-band (or similar) signals for remote sensing is differentiating the effects of soil moisture and vegetation on the retrieval of hydrologic variables. This same challenge exists when using GPS-IR data. We have established nine research sites with identical GPS and hydrologic infrastructure to study this problem. These sites span a wide range of soil, vegetation, and climate types. In addition to daily GPS and hourly soil moisture data, we have collected weekly vegetation water content samples at all sites. Our data demonstrate that soil moisture fluctuations can be estimated from GPS-IR records when vegetation water content is low (< 2 kg m-2). We outline different approaches for separating the soil moisture and vegetation signals and quantifying errors in our retrieval algorithm.

  11. Role of native and exotic woody vegetation in soil restoration in active gully systems (southern Ecuador)

    NASA Astrophysics Data System (ADS)

    Borja Ramon, Pablo; Alvarado Moncayo, Dario; Vanacker, Veerle; Cisneros, Pedro; Molina, Armando; Govers, Gerard

    2015-04-01

    Revegetation projects in degraded lands have the potential to recover essential soil functions. If vegetation restoration is combined with bioengineering techniques, such as the construction of retention dams in active gully systems, soil restoration could be enhanced. One important aspect of this process is the role of vegetation on restoration of soil chemical and physical properties. There is currently a lack of knowledge on the potential of soil restoration in active badland systems, as most studies have concentrated on the direct and visible effect of revegetation on erosion control. The aim of this study is to evaluate the role of revegetation and bioengineering works on the restoration of soil physical and chemical properties. The analyses are realized in a highly degraded area of 3 km2, located in the lower part of the Loreto catchment (Southern Ecuadorian Andes). First, the soil physical and/or chemical parameters that are most sensitive to track environmental change were evaluated. Second, the role of vegetation on soil restoration was quantified. . Soil samples were taken in sites with different vegetation cover, land use and physiographic position. The following physical and chemical parameters were measured: volumetric water content (θsat, θact), bulk density, pH, texture, organic matter, C and N content. Our first results do not show a clear relationship between volumetric water content at saturation (θsat), bulk density, or C content. The saturation water content does not vary significantly between different sites, or land use types. However, significant differences are found between sites at different stages of restoration; and this for most chemical and physical soil properties. Vegetation cover (%) appears to exert a strong control on the C content in the mineral soils. The highest C values are found in soils of forest plantations with Eucalyptus and Pinus species. These plantations are located in areas that were previously affected by active

  12. Mercury in vegetation and soils at abandoned mercury mines in southwestern Alaska, USA

    USGS Publications Warehouse

    Bailey, E.A.; Gray, J.E.; Theodorakos, P.M.

    2002-01-01

    We chemically analysed vegetation (willow and alder) and soil samples collected at three abandoned mercury (Hg) mines and at background sites in southwestern Alaska and compared Hg concentrations, speciation and distribution. Total Hg and methylmercury (MeHg) concentrations were higher in vegetation and soil samples from all the mine sites compared to samples from the background sites, but there was no correlation between total-Hg concentrations in vegetation and total-Hg concentrations in soil or between total-Hg and MeHg concentrations. However, the percent MeHg of the total Hg was higher in samples from the background sites compared to samples from the mine sites and is higher in vegetation samples than in corresponding soil samples. The percent MeHg is an order of magnitude higher in the willow samples than in corresponding alder or soil samples. The percent of divalent Hg [Hg(II)] is highest in soil samples from the retort and background areas. The higher percent MeHg in vegetation and soil in samples from background sites may be explained by the higher proportions of reactive Hg species, such as Hg(II), at these sites compared to the surface mined and tailings areas where most of the Hg is in the elemental and cinnabar (HgS) forms. Dissolved gaseous Hg species are more readily accumulated in vegetation and are more readily methylated than solid phases like HgS and liquid Hg.

  13. [Heidaigou Opencast Coal Mine: Soil Enzyme Activities and Soil Physical and Chemical Properties Under Different Vegetation Restoration].

    PubMed

    Fang, Ying; Ma, Ren-tian; An, Shao-shan; Zhao, Jun-feng; Xiao, Li

    2016-03-15

    Choosing the soils under different vegetation recovery of Heidaigou dump as the research objects, we mainly analyzed their basic physical and chemical properties and enzyme activities with the method of Analysis of Variance as well as their relations using Pearson correlation analysis and path analysis hoping to uncover the driving factors of the differences between soil enzyme activities under different vegetation restoration, and provide scientific suggestions for the plant selection as well as make a better evaluation to the reclamation effect. The results showed that: (1) Although the artificial vegetation restoration improved the basic physical and chemical properties of the soils while increasing their enzyme activities to a certain extent, the soil conditions still did not reach the level of the natural grassland; (2) Contents of soil organic carbon (SOC) and soil total nitrogen (TN) of the seabuckthorns were the nearest to those of the grassland, which reached 54. 22% and 70. 00% of those of the grassland. In addition, the soil bulk density of the seabuckthorns stand was 17. 09% lower than the maximum value of the amorpha fruitcosa land. The SOC and TN contents as well as the bulk density showed that seabuckthorns had advantages as the species for land reclamation of this dump; Compared with the seabuckthorn, the pure poplar forest had lower contents of SOC and TN respectively by 35.64% and 32.14% and displayed a 16.79% higher value of soil bulk density; (3) The activities of alkaline phosphotase under different types of vegetation rehabilitation had little variation. But soil urease activities was more sensitive to reflect the effects of vegetation restoration on soil properties; (4) Elevation of the SOC and TN turned out to be the main cause for soil fertility restoration and increased biological activities of the dump.

  14. Bioremediation of petroleum contaminated soil using vegetation. A microbial study

    SciTech Connect

    Lee, E.; Banks, M.K. )

    1993-12-01

    The degradation of selected petroleum hydrocarbons in the rhizosphere of alfalfa was investigated in a greenhouse experiment. Petroleum contaminated and uncontaminated soils were spiked with 100 ppm of polynuclear aromatic and aliphatic hydrocarbons. Unspiked, uncontaminated soil was used as a control. Microbial counts for soils with and without plants for each soil treatment were performed 4, 8, 16, and 24 weeks after planting. Microbial numbers were substantially greater in soil with plants when compared to soil containing no plants, indicating that plant roots enhanced microbial populations in contaminated soil. Soil treatments had no effect on microbial numbers in the presence of plants. 12 refs., 3 figs., 1 tab.

  15. Measuring and modelling water related soil-vegetation feedbacks in a fallow plot

    NASA Astrophysics Data System (ADS)

    Ursino, N.; Cassiani, G.; Deiana, R.; Vignoli, G.; Boaga, J.

    2013-08-01

    Land fallowing is one possible response to shortage of water for irrigation. Leaving the soil unseeded implies a change of the soil functioning that has an impact on the water cycle. The development of a soil crust in the open spaces between the patterns of grass weed affects the soil properties and the field scale water balance. The objectives of this study are to test the potential of integrated non invasive geophysical methods and ground-image analysis and to quantify the effect of the soil vegetation interaction on the water balance of a fallow land at the local and plot scale. We measured repeatedly in space and time local soil saturation and vegetation cover over two small plots located in southern Sardinia, Italy, during a controlled irrigation experiment. One plot was left unseeded and the other was cultivated. The comparative analysis of ERT maps of soil moisture evidenced a considerably different hydrologic response to irrigation of the two plots. Local measurements of soil saturation and vegetation cover were repeated in space to evidence a positive feedback between weed growth and infiltration at the fallow plot. A simple bucket model captured the different soil moisture dynamics at the two plots during the infiltration experiment and was used to estimate the impact of the soil vegetation feedback on the yearly water balance at the fallow site.

  16. Measuring and modeling water-related soil-vegetation feedbacks in a fallow plot

    NASA Astrophysics Data System (ADS)

    Ursino, N.; Cassiani, G.; Deiana, R.; Vignoli, G.; Boaga, J.

    2014-03-01

    Land fallowing is one possible response to shortage of water for irrigation. Leaving the soil unseeded implies a change of the soil functioning that has an impact on the water cycle. The development of a soil crust in the open spaces between the patterns of grass weed affects the soil properties and the field-scale water balance. The objectives of this study are to test the potential of integrated non-invasive geophysical methods and ground-image analysis and to quantify the effect of the soil-vegetation interaction on the water balance of fallow land at the local- and plot scale. We measured repeatedly in space and time local soil saturation and vegetation cover over two small plots located in southern Sardinia, Italy, during a controlled irrigation experiment. One plot was left unseeded and the other was cultivated. The comparative analysis of ERT maps of soil moisture evidenced a considerably different hydrologic response to irrigation of the two plots. Local measurements of soil saturation and vegetation cover were repeated in space to evidence a positive feedback between weed growth and infiltration at the fallow plot. A simple bucket model captured the different soil moisture dynamics at the two plots during the infiltration experiment and was used to estimate the impact of the soil vegetation feedback on the yearly water balance at the fallow site.

  17. Pesticides in western Canadian mountain air and soil.

    PubMed

    Daly, Gillian L; Lei, Ying D; Teixeira, Camilla; Muir, Derek C G; Wania, Frank

    2007-09-01

    The distribution of organochlorine pesticides (OCP; in past and current use) in the mountains of western Canada was determined by sampling air, soil, and lichen along three elevational transects in 2003-2004. Two transects west of the Continental Divide were located in Mount Revelstoke and Yoho National Park, while the Observation Peak transect in Banff National Park is east of the divide. XAD-based passive air samplers, yielding annually averaged air concentrations, were deployed, and soils were collected at all 22 sampling sites, whereas lichen were only sampled in Revelstoke. Back trajectory analysis showed limited air mass transport from the Prairies to the east, but a high frequency of air arriving from the southwest, which includes agricultural regions in British Columbia and Washington State. Endosulfan, dieldrin, and a-hexachlorocyclohexane were the most prevalent OCPs in air and soil; hexachlorobenzene was only abundant in air; chlorothalonil, dacthal, and pentachloronitrobenzene were also consistently present. OCP air concentrations were similar across the three transects, suggesting efficient atmospheric mixing on a local and regional scale. Soil concentrations and soil/air concentration ratios of many OCPs were significantly higher west of the Continental Divide. The soil and lichen concentrations of most OCPs increased with altitude in Revelstoke, and displayed maxima at intermediate elevations at Yoho and Observation Peak. These distribution patterns can be understood as being determined by the balance between atmospheric deposition to, and retention within, the soils. Higher deposition, due to more precipitation falling at lower temperatures, likely occurs west of the divide and at higher elevations. Higher retention, due to higher soil organic matter content, is believed to occur in soils below the tree line. Highest pesticide concentrations are thus found intemperate mountain soils that are rich in organic matter and receive large amounts of cold

  18. [Characteristics of soil microbial community under different vegetation types in Wuyishan National Nature Reserve, East China].

    PubMed

    Wu, Ze-yan; Lin, Wen-xiong; Chen, Zhi-fang; Fang, Chang-xun; Zhang, Zhi-xing; Wu, Lin-kun; Zhou, Ming-ming; Shen, Li-hua

    2013-08-01

    By using Biolog Ecoplate system, this paper studied the structure and functional diversity of soil microbial community under different vegetation types in Wuyishan National Nature Reserve, aimed to probe into the effects of vegetation type on the diversity of soil microbial community. The results showed that the soil chemical properties, soil enzyme activities, and average well color development (AWCD) were higher in natural forest than in planted forest, and were the lowest in abandoned field. The AWCD reflecting soil microbial activity and functional diversity was increased with increasing incubation time, but there existed significant differences among different vegetation types. The carbon sources mostly used by soil microbes were carbohydrates and carboxylic acids, followed by amino acids, phenolic acids and polymers, and amines had the lowest utilization rate. The Simpson index, Shannon index, Richness index and McIntosh index in natural forest were holistically higher than those in planted forest. Principal component analysis (PCA) identified 2 principal component factors in relation to carbon sources, explaining 56.3% and 30.2% of the variation, respectively. The carbon sources used by soil microbial community differed with vegetation types. Amino acids and amides were the two main carbon sources separating the 2 principal component factors. The results of this study could provide basis for further approaching the relationships between vegetation diversity and soil microbial community diversity.

  19. Soil-vegetation correlations in selected wetlands and uplands of North-Central Florida

    USGS Publications Warehouse

    Best, G. Ronnie; Wolfe, Charlotte; Segal, Debra S.

    1990-01-01

    Vegetation on four hydric and two nonhydric soils series in north-central Florida was sampled as part of a national study examining the correspondence between wetland vegetation and soils. The wetland character of the vegetation was estimated by weighted average calculations using published wetland indicator values for individual plant species. The weighted averages produced an ordering of plant communities in general agreement with the hydric character of the soils. However, the two nonhydric soils has weighted average scores slightly below 3, normally considered the lowest end of the range of nonhydric vegetation. There was no clear or consistent effect of fire management on the weighted average scores. Vegetation strata (herbaceous, low shrub, tall shrub, and trees) were generally similar in weighted average values, with the wettest of the hydric soils tending to be low in all strata and the nonhydric soils tending to be high in all strata. However, strata differed considerably in the specific values for a single soil and in the specific rank ordering of soils in different strata.

  20. TECHNOLOGY ASSESSMENT OF SOIL VAPOR EXTRACTION AND AIR SPARGING

    EPA Science Inventory

    Air sparging, also called "in situ air stripping and in situ volatilization" injects air into the saturated zone to strip away volatile organic compounds (VOCs) dissolved in groundwater and adsorbed to soil. hese volatile contaminants transfer in a vapor phase to the unsaturated ...

  1. Ecological optimality in water-limited natural soil-vegetation systems. II - Tests and applications

    NASA Technical Reports Server (NTRS)

    Eagleson, P. S.; Tellers, T. E.

    1982-01-01

    The long-term optimal climatic climax soil-vegetation system is defined for several climates according to previous hypotheses in terms of two free parameters, effective porosity and plant water use coefficient. The free parameters are chosen by matching the predicted and observed average annual water yield. The resulting climax soil and vegetation properties are tested by comparison with independent observations of canopy density and average annual surface runoff. The climax properties are shown also to satisfy a previous hypothesis for short-term optimization of canopy density and water use coefficient. Using these hypotheses, a relationship between average evapotranspiration and optimum vegetation canopy density is derived and is compared with additional field observations. An algorithm is suggested by which the climax soil and vegetation properties can be calculated given only the climate parameters and the soil effective porosity. Sensitivity of the climax properties to the effective porosity is explored.

  2. On soil moisture-vegetation feedbacks and their possible effects on the dynamics of dryland ecosystems

    NASA Astrophysics Data System (ADS)

    D'Odorico, Paolo; Caylor, Kelly; Okin, Gregory S.; Scanlon, Todd M.

    2007-12-01

    Soil moisture is the environmental variable synthesizing the effect of climate, soil, and vegetation on the dynamics of water-limited ecosystems. Unlike abiotic factors (e.g., soil texture and rainfall regime), the control exerted by vegetation composition and structure on soil moisture variability remains poorly understood. A number of field studies in dryland landscapes have found higher soil water contents in vegetated soil patches than in adjacent bare soil, providing a convincing explanation for the observed preferential establishment of grasses and seedlings beneath tree canopies. Thus, because water is the limiting factor for vegetation in arid and semiarid ecosystems, a positive feedback could exist between soil moisture and woody vegetation dynamics. It is still unclear how the strength of such a feedback would change under different long-term rainfall regimes. To this end, we report some field observations from savanna ecosystems located along the south-north rainfall gradient in the Kalahari, where the presence of relatively uniform sandy soils limits the effects of covarying factors. The data available from our field study suggest that the contrast between the soil moisture in the canopy and intercanopy space increases (with wetter soils under the canopy) with increasing levels of aridity. We hypothesize that this contrast may lead to a positive feedback and explore the implications of such a feedback in a minimalistic model. We found that when the feedback is relatively strong, the system may exhibit two stable states corresponding to conditions with and without tree canopy cover. In this case, even small changes in environmental variables may lead to rapid and largely irreversible shifts to a state with no tree canopy cover. Our data suggest that the tendency of the system to exhibit two (alternative) stable states becomes stronger in the more arid regions. Thus, at the desert margins, vegetation is more likely to be prone to discontinuous and abrupt

  3. Concentration and transportation of heavy metals in vegetables and risk assessment of human exposure to bioaccessible heavy metals in soil near a waste-incinerator site, South China.

    PubMed

    Li, Ning; Kang, Yuan; Pan, Weijian; Zeng, Lixuan; Zhang, Qiuyun; Luo, Jiwen

    2015-07-15

    There is limited study focusing on the bioaccumulation of heavy metals in vegetables and human exposure to bioaccessible heavy metals in soil. In the present study, heavy metal concentrations (Cr, Ni, Cu, Pb and Cd) were measured in five types of vegetables, soil, root, and settled air particle samples from two sites (at a domestic waste incinerator and at 20km away from the incinerator) in Guangzhou, South China. Heavy metal concentrations in soil were greater than those in aerial parts of vegetables and roots, which indicated that vegetables bioaccumulated low amount of heavy metals from soil. The similar pattern of heavy metal (Cr, Cd) was found in the settled air particle samples and aerial parts of vegetables from two sites, which may suggest that foliar uptake may be an important pathway of heavy metal from the environment to vegetables. The highest levels of heavy metals were found in leaf lettuce (125.52μg/g, dry weight) and bitter lettuce (71.2μg/g) for sites A and B, respectively, followed by bitter lettuce and leaf lettuce for sites A and B, respectively. Swamp morning glory accumulated the lowest amount of heavy metals (81.02μg/g for site A and 53.2μg/g for site B) at both sites. The bioaccessibility of heavy metals in soil ranged from Cr (2%) to Cu (71.78%). Risk assessment showed that Cd and Pb in soil samples resulted in the highest non-cancer risk and Cd would result in unacceptable cancer risk for children and risk. The non-dietary intake of soil was the most important exposure pathway, when the bioaccessibility of heavy metals was taken into account.

  4. Phosphorus in China's Intensive Vegetable Production Systems: Overfertilization, Soil Enrichment, and Environmental Implications.

    PubMed

    Yan, Zhengjuan; Liu, Pengpeng; Li, Yuhong; Ma, Lin; Alva, Ashok; Dou, Zhengxia; Chen, Qing; Zhang, Fusuo

    2013-07-01

    China's vegetable production has experienced a rapid growth in recent years. Total production amounted to 522.7 million Mg (1 Mg = 10 g) in 2009, which was more than nine times that in 1980 and represented >50% of the world production. Meanwhile, excessive use of animal manures and chemical fertilizers in vegetable fields has brought various production and environmental challenges, including excessive accumulation of nutrients in soils and accelerated water pollution problems. In this study, we have evaluated the current status of phosphorus (P) in China's intensive vegetable production systems based on data summarized from nearly 100 publications plus results from our recent experiments. Gross overfertilization occurred in greenhouse (571 kg P ha) and open-field (117 kg P ha) vegetable systems compared with P removal in harvested crops (44 and 25 kg P ha) per season. Excess P input led to soil enrichment of labile P, measured as Olsen-P, averaging 179 (greenhouses) and 100 mg P kg (open fields) in the 0- to 20-cm soil depth, and in some cases led to P leaching, as evidenced by increases in Olsen-P and CaCl-P at the 40- to 60-cm soil depth. The vast majority of vegetable soils had Olsen-P exceeding the critical level (46.0-58.0 mg P kg) for optimum vegetable yield. Innovative policies and strategies are urgently needed to implement science-based nutrient management practices to attain sustainable vegetable production while protecting natural and environmental resources.

  5. Estimation of Soil Moisture for Vegetated Surfaces Using Multi-Temporal L-Band SAR Measurements

    NASA Technical Reports Server (NTRS)

    Shi, Jian-Cheng; Sun, G.; Hsu, A.; Wang, J.; ONeill, P.; Ranson, J.; Engman, E. T.

    1997-01-01

    This paper demonstrates the technique to estimate ground surface and vegetation scattering components, based on the backscattering model and the radar decomposition theory, under configuration of multi-temporal L-band polarimetric SAR measurement. This technique can be used to estimate soil moisture of vegetated surface.

  6. Trampling resistance of tropical rainforest soils and vegetation in the wet tropics of north east Australia.

    PubMed

    Talbot, L M; Turton, S M; Graham, A W

    2003-09-01

    Controlled trampling was conducted to investigate the trampling resistance of contrasting high fertility basaltic and low fertility rhyolitic soils and their associated highland tropical rainforest vegetation in north east Australia's Wet Tropics. Although this approach has been taken in numerous studies of trampling in a variety of ecosystem types (temperate and subtropical forest, alpine shrubland, coral reef and seagrass beds), the experimental method does not appear to have been previously applied in a tropical rainforest context. Ground vegetation cover and soil penetration resistance demonstrated variable responses to trampling. Trampling, most noticeably after 200 and 500 passes reduced organic litter cover. Bulk density increased with trampling intensity, particularly on basalt soils as rhyolite soils appeared somewhat resistant to the impacts of trampling. The permeability of the basalt and rhyolite soils decreased markedly with increased trampling intensity, even after only 75 passes. These findings suggest physical and hydrological changes may occur rapidly in tropical rainforest soils following low levels of trampling, particularly on basalt soils.

  7. Improved Prediction of Quasi-Global Vegetation Conditions Using Remotely-Sensed Surface Soil Moisture

    NASA Technical Reports Server (NTRS)

    Bolten, John; Crow, Wade

    2012-01-01

    The added value of satellite-based surface soil moisture retrievals for agricultural drought monitoring is assessed by calculating the lagged rank correlation between remotely-sensed vegetation indices (VI) and soil moisture estimates obtained both before and after the assimilation of surface soil moisture retrievals derived from the Advanced Microwave Scanning Radiometer-EOS (AMSR-E) into a soil water balance model. Higher soil moisture/VI lag correlations imply an enhanced ability to predict future vegetation conditions using estimates of current soil moisture. Results demonstrate that the assimilation of AMSR-E surface soil moisture retrievals substantially improve the performance of a global drought monitoring system - particularly in sparsely-instrumented areas of the world where high-quality rainfall observations are unavailable.

  8. Spatial variability of the properties of marsh soils and their impact on vegetation

    NASA Astrophysics Data System (ADS)

    Sidorova, V. A.; Svyatova, E. N.; Tseits, M. A.

    2015-03-01

    Spatial variability of the properties of soils and the character of vegetation was studied on seacoasts of the Velikii Island in the Kandalaksha Bay of the White Sea. It was found that the chemical and physicochemical properties of marsh soils (Tidalic Fluvisols) are largely dictated by the distance from the sea and elevation of the sampling point above sea level. The spatial distribution of the soil properties is described by a quadratic trend surface. With an increase in the distance from the sea, the concentration of ions in the soil solution decreases, and the organic carbon content and soil acidity become higher. The spatial dependence of the degree of variability in the soil properties is moderate. Regular changes in the soil properties along the sea-land gradient are accompanied by the presence of specific spatial patterns related to the system of temporary water streams, huge boulders, and beached heaps of sea algae and wood debris. The cluster analysis made it possible to distinguish between five soil classes corresponding to the following plant communities: barren surface (no permanent vegetation), clayey-sandy littoral with sparse halophytes, marsh with large rhizomatous grasses, and grass-forb-bunchberry vegetation of forest margins. The subdivision into classes is especially distinct with respect to the concentration of chloride ions. The following groups of factors affect the distribution of vegetation: the composition of the soil solution, the height above sea level, the pH of water suspensions, and the humus content.

  9. [Soil infiltration capacity under different vegetations in southern Ningxia Loess hilly region].

    PubMed

    Yang, Yong-Hui; Zhao, Shi-Wei; Lei, Ting-Wu; Liu, Han

    2008-05-01

    A new apparatus for measuring the run off-on-out under simulated rainfall conditions was used to study the soil infiltration capacity under different rainfall intensities and vegetations in loess hilly region of southern Ningxia, with the relationships between soil water-stable aggregate content and soil stable infiltration rate under different vegetations analyzed. The results showed that the regression equations between rainfall duration and soil infiltration rate under different vegetations all followed y = a + be(-cx), with R2 ranged from 0.9678 to 0.9969. With the increase of rainfall intensity, the soil stable infiltration rate on slope cropland decreased, while that on Medicago lupulina land, natural grassland, and Caragana korshinskii land increased. Under the rainfall intensity of 20 mm h(-1), the rainfall infiltration translation rate (RITR) was decreased in the order of M. lupulina land > slope cropland > natural grassland > C. korshinskii land; while under the rainfall intensity of 40 mm h(-1) and 56 mm h(-1), the RITR was in the sequence of M. lupulina land > natural grassland > slope cropland > C. korshinskii land, and decreased with increasing rainfall intensity. After the reversion of cropland to grassland and forest land, and with the increase of re-vegetation, the amount of >0.25 mm soil aggregates increased, and soil infiltration capacity improved. The revegetation in study area effectively improved soil structure and soil infiltration capacity, and enhanced the utilization potential of rainfall on slope.

  10. Magnesium retention on the soil exchange complex controlling Mg isotope variations in soils, soil solutions and vegetation in volcanic soils, Iceland

    NASA Astrophysics Data System (ADS)

    Opfergelt, S.; Burton, K. W.; Georg, R. B.; West, A. J.; Guicharnaud, R. A.; Sigfusson, B.; Siebert, C.; Gislason, S. R.; Halliday, A. N.

    2014-01-01

    Understanding the biogeochemical cycle of magnesium (Mg) is not only crucial for terrestrial ecology, as this element is a key nutrient for plants, but also for quantifying chemical weathering fluxes of Mg and associated atmospheric CO2 consumption, requiring distinction of biotic from abiotic contributions to Mg fluxes exported to the hydrosphere. Here, Mg isotope compositions are reported for parent basalt, bulk soils, clay fractions, exchangeable Mg, seasonal soil solutions, and vegetation for five types of volcanic soils in Iceland in order to improve the understanding of sources and processes controlling Mg supply to vegetation and export to the hydrosphere. Bulk soils (δ26Mg = -0.40 ± 0.11‰) are isotopically similar to the parent basalt (δ26Mg = -0.31‰), whereas clay fractions (δ26Mg = -0.62 ± 0.12‰), exchangeable Mg (δ26Mg = -0.75 ± 0.14‰), and soil solutions (δ26Mg = -0.89 ± 0.16‰) are all isotopically lighter than the basalt. These compositions can be explained by a combination of mixing and isotope fractionation processes on the soil exchange complex. Successive adsorption-desorption of heavy Mg isotopes leads to the preferential loss of heavy Mg from the soil profile, leaving soils with light Mg isotope compositions relative to the parent basalt. Additionally, external contributions from sea spray and organic matter decomposition result in a mixture of Mg sources on the soil exchange complex. Vegetation preferentially takes up heavy Mg from the soil exchange complex (Δ26Mgplant-exch = +0.50 ± 0.09‰), and changes in δ26Mg in vegetation reflect changes in bioavailable Mg sources in soils. This study highlights the major role of Mg retention on the soil exchange complex amongst the factors controlling Mg isotope variations in soils and soil solutions, and demonstrates that Mg isotopes provide a valuable tool for monitoring biotic and abiotic contributions of Mg that is bioavailable for plants and is exported to the hydrosphere.

  11. Temporal Variations in Soil Moisture for Three Typical Vegetation Types in Inner Mongolia, Northern China

    PubMed Central

    Zheng, Hao; Gao, Jixi; Teng, Yanguo; Feng, Chaoyang; Tian, Meirong

    2015-01-01

    Drought and shortages of soil water are becoming extremely severe due to global climate change. A better understanding of the relationship between vegetation type and soil-moisture conditions is crucial for conserving soil water in forests and for maintaining a favorable hydrological balance in semiarid areas, such as the Saihanwula National Nature Reserve in Inner Mongolia, China. We investigated the temporal dynamics of soil moisture in this reserve to a depth of 40 cm under three types of vegetation during a period of rainwater recharge. Rainwater from most rainfalls recharged the soil water poorly below 40 cm, and the rainfall threshold for increasing the moisture content of surface soil for the three vegetations was in the order: artificial Larix spp. (AL) > Quercus mongolica (QM) > unused grassland (UG). QM had the highest mean soil moisture content (21.13%) during the monitoring period, followed by UG (16.52%) and AL (14.55%); and the lowest coefficient of variation (CV 9.6-12.5%), followed by UG (CV 10.9-18.7%) and AL (CV 13.9-21.0%). QM soil had a higher nutrient content and higher soil porosities, which were likely responsible for the higher ability of this cover to retain soil water. The relatively smaller QM trees were able to maintain soil moisture better in the study area. PMID:25781333

  12. Soil environmental quality in greenhouse vegetable production systems in eastern China: Current status and management strategies.

    PubMed

    Hu, Wenyou; Zhang, Yanxia; Huang, Biao; Teng, Ying

    2017-03-01

    Greenhouse vegetable production (GVP) has become an important source of public vegetable consumption and farmers' income in China. However, various pollutants can be accumulated in GVP soils due to the high cropping index, large agricultural input, and closed environment. Ecological toxicity caused by excessive pollutants' accumulation can then lead to serious health risks. This paper was aimed to systematically review the current status of soil environmental quality, analyze their impact factors, and consequently to propose integrated management strategies for GVP systems. Results indicated a decrease in soil pH, soil salinization, and nutrients imbalance in GVP soils. Fungicides, remaining nutrients, antibiotics, heavy metals, and phthalate esters were main pollutants accumulating in GVP soils comparing to surrounding open field soils. Degradation of soil ecological function, accumulation of major pollutants in vegetables, deterioration of neighboring water bodies, and potential human health risks has occurred due to the changes of soil properties and accumulation of pollutants such as heavy metals and fungicides in soils. Four dominant factors were identified leading to the above-mentioned issues including heavy application of agricultural inputs, outmoded planting styles with poor environmental protection awareness, old-fashion regulations, unreasonable standards, and ineffective supervisory management. To guarantee a sustainable GVP development, several strategies were suggested to protect and improve soil environmental quality. Implementation of various strategies not only requires the concerted efforts among different stakeholders, but also the whole lifecycle assessment throughout the GVP processes as well as effective enforcement of policies, laws, and regulations.

  13. STOMP Sparse Vegetation Evapotranspiration Model for the Water-Air-Energy Operational Mode

    SciTech Connect

    Ward, Anderson L.; White, Mark D.; Freeman, Eugene J.; Zhang, Z. F.

    2005-09-15

    The Water-Air-Energy (WAE) Operational Mode of the Subsurface Transport Over Multiple Phases (STOMP) numerical simulator solves the coupled conservation equations for water mass, air mass, and thermal energy in multiple dimensions. This addendum describes the theory, input file formatting, and application of a soil-vegetation-atmosphere transfer (SVAT) scheme for STOMP that is based on a sparse vegetation evapotranspiration model. The SVAT scheme is implemented as a boundary condition on the upper surface of the computational domain and has capabilities for simulating evaporation from bare surfaces as well as evapotranspiration from sparsely vegetated surfaces populated with single or multiple plant species in response to meteorological forcings. With this extension, the model calculates water mass, air mass and thermal energy across a boundary surface in addition to root-water transport between the subsurface and atmosphere. This mode represents the barrier extension of the WAE mode and is designated as STOMP-WAE-B. Input for STOMP-WAE-B is specified via three input cards and include: atmospheric conditions through the Atmospheric Conditions Card; time-invariant plant species data through the Plant Properties Card; and time varying plant species data through the Boundary Conditions Card. Two optional cards, the Observed Data and UCODE Control Cards allow use of STOMP-WAE with UCODE in an inverse mode to estimate model parameters. STOMP-WAE was validated by solving a number of test problems from the literature that included experimental observations as well as analytical or numerical solutions. Several of the UNSAT-H verification problems are included along with a benchmark simulation derived from a recently published intercode comparison for barrier design tools. Results show that STOMP is able to meet, and in most cases, exceed performance of other commonly used simulation codes without having to resort to may of their simplifying assumptions. Use of the fully

  14. Multi-discipline resource inventory of soils, vegetation and geology

    NASA Technical Reports Server (NTRS)

    Simonson, G. H. (Principal Investigator); Paine, D. P.; Lawrence, R. D.; Norgren, J. A.; Pyott, W. Y.; Herzog, J. H.; Murray, R. J.; Rogers, R.

    1973-01-01

    The author has identified the following significant results. Computer classification of natural vegetation, in the vicinity of Big Summit Prairie, Crook County, Oregon was carried out using MSS digital data. Impure training sets, representing eleven vegetation types plus water, were selected from within the area to be classified. Close correlations were visually observed between vegetation types mapped from the large scale photographs and the computer classification of the ERTS data (Frame 1021-18151, 13 August 1972).

  15. Radiation budget and soil heat fluxes in different Arctic tundra vegetation types

    NASA Astrophysics Data System (ADS)

    Juszak, Inge; Iturrate Garcia, Maitane; Gastellu-Etchegorry, Jean-Philippe; Schaepman, Michael E.; Schaepman-Strub, Gabriela

    2016-04-01

    While solar radiation is one of the primary energy sources for warming and thawing permafrost soil, the amount of shortwave radiation reaching the soil is reduced by vegetation shading. Climate change has led to greening, shrub expansion and encroachment in many Arctic tundra regions and further changes are anticipated. These vegetation changes feed back to the atmosphere and permafrost as they modify the surface energy budget. However, canopy transmittance of solar radiation has rarely been measured or modelled for a variety of tundra vegetation types. We assessed the radiation budget of the most common vegetation types at the Kytalyk field site in North-East Siberia (70.8°N, 147.5°E) with field measurements and 3D radiative transfer modelling and linked it to soil heat fluxes. Our results show that Arctic tundra vegetation types differ in canopy albedo and transmittance as well as in soil heat flux and active layer thickness. Tussock sedges transmitted on average 56% of the incoming light and dwarf shrubs 27%. For wet sedges we found that the litter layer was very important as it reduced the average transmittance to only 6%. Model output indicated that both, albedo and transmittance, also depend on the spatial aggregation of vegetation types. We found that permafrost thaw was more strongly related to soil properties than to canopy shading. The presented radiative transfer model allows quantifying effects of the vegetation layer on the surface radiation budget in permafrost areas. The parametrised model can account for diverse vegetation types and variation of properties within types. Our results highlight small scale radiation budget and permafrost thaw variability which are indicated and partly caused by vegetation. As changes in species composition and biomass increase can influence thaw rates, small scale patterns should be considered in assessments of climate-vegetation-permafrost feedbacks.

  16. [Soil infiltration characteristics under main vegetation types in Anji County of Zhejiang Province].

    PubMed

    Liu, Dao-Ping; Chen, San-Xiong; Zhang, Jin-Chi; Xie, Li; Jiang, Jiang

    2007-03-01

    The study on the soil infiltration under different main vegetation types in Anji County of Zhejiang Province showed that the characteristics of soil infiltration differed significantly with land use type, and the test eight vegetation types could be classified into four groups, based on soil infiltration capability. The first group, deciduous broadleaved forest, had the strongest soil infiltration capability, and the second group with a stronger soil infiltration capability was composed of grass, pine forest, shrub community and tea bush. Bamboo and evergreen broadleaved forest were classified into the third group with a relatively strong soil infiltration capability, while bare land belonged to the fourth group because of the bad soil structure and poorest soil infiltration capability. The comprehensive parameters of soil infiltration (alpha) and root (beta) were obtained by principal component analysis, and the regression model of alpha and beta could be described as alpha = 0. 1708ebeta -0. 3122. Soil infiltration capability was greatly affected by soil physical and chemical characteristics and root system. Fine roots (< or = 1 mm in diameter) played effective roles on the improvement of soil physical and chemical properties, and the increase of soil infiltration capability was closely related to the amount of the fine roots.

  17. Research of the diurnal soil respiration dynamic in two typical vegetation communities in Tianjin estuarine wetland

    NASA Astrophysics Data System (ADS)

    Zhang, Q.; Meng, W. Q.; Li, H. Y.

    2016-08-01

    Understanding the differences and diurnal variations of soil respiration in different vegetation communities in coastal wetland is to provide basic reliable scientific evidence for the carbon "source" function of wetland ecosystems in Tianjin.Measured soil respiration rate which changed during a day between two typical vegetation communities (Phragmites australis, Suaeda salsa) in coastal wetland in October, 2015. Soil temperature and moisture were measured at the same time. Each of the diurnal curves of soil temperature in two communities had a single peak value, and the diurnal variations of soil moisture showed a "two peak-one valley" trend. The diurnal dynamic of soil respiration under the two communities had obvious volatility which showed a single peak form with its maximum between 12:00-14:00 and minimum during 18:00. The diurnal average of soil respiration rate in Phragmites australis communities was 3.37 times of that in Suaeda salsa communities. Significant relationships were found by regression analysis among soil temperature, soil moisture and soil respiration rate in Suaeda salsa communities. There could be well described by exponential models which was y = -0.245e0.105t between soil respiration rate and soil temperature, by quadratic models which was y = -0.276×2 + 15.277× - 209.566 between soil respiration rate and soil moisture. But the results of this study showed that there were no significant correlations between soil respiration and soil temperature and soil moisture in Phragmites australis communities (P > 0.05). Therefore, under the specific wetland environment conditions in Tianjin, soil temperature and moisture were not main factors influencing the diurnal variations of soil respiration rate in Phragmites australis communities.

  18. Modeling the effects of vegetation on methane oxidation and emissions through soil landfill final covers across different climates.

    PubMed

    Abichou, Tarek; Kormi, Tarek; Yuan, Lei; Johnson, Terry; Francisco, Escobar

    2015-02-01

    Plant roots are reported to enhance the aeration of soil by creating secondary macropores which improve the diffusion of oxygen into soil as well as the supply of methane to bacteria. Therefore, methane oxidation can be improved considerably by the soil structuring processes of vegetation, along with the increase of organic biomass in the soil associated with plant roots. This study consisted of using a numerical model that combines flow of water and heat with gas transport and oxidation in soils, to simulate methane emission and oxidation through simulated vegetated and non-vegetated landfill covers under different climatic conditions. Different simulations were performed using different methane loading flux (5-200 g m(-2) d(-1)) as the bottom boundary. The lowest modeled surface emissions were always obtained with vegetated soil covers for all simulated climates. The largest differences in simulated surface emissions between the vegetated and non-vegetated scenarios occur during the growing season. Higher average yearly percent oxidation was obtained in simulations with vegetated soil covers as compared to non-vegetated scenario. The modeled effects of vegetation on methane surface emissions and percent oxidation were attributed to two separate mechanisms: (1) increase in methane oxidation associated with the change of the physical properties of the upper vegetative layer and (2) increase in organic matter associated with vegetated soil layers. Finally, correlations between percent oxidation and methane loading into simulated vegetated and non-vegetated covers were proposed to allow decision makers to compare vegetated versus non-vegetated soil landfill covers. These results were obtained using a modeling study with several simplifying assumptions that do not capture the complexities of vegetated soils under field conditions.

  19. Combined effect of soil erosion and climate change induces abrupt changes in soil and vegetation properties in semiarid Mediterranean shrublands.

    NASA Astrophysics Data System (ADS)

    Bochet, Esther; García-Fayos, Patricio

    2013-04-01

    Semiarid Mediterranean ecosystems are experiencing major alterations as a result of the complex interactions between climatic fluctuations and disturbances caused by human activities. Future scenarios of global change forecast a rapid degradation of these ecosystems, with a reduction of their functionality, as a result of changes in relevant vegetation and soil properties. Some theoretical models indicate that these ecosystems respond non-linearly to regular variations in the external conditions, with an abrupt shift when conditions approach a certain critical level or threshold. Considering these predictions, there is an urgent need to know the effects that these alterations might have on semi-arid ecosystems and their components. In this study, we aim at analyzing the consequences of climate change and increasing soil erosion on soil and vegetation properties and the functional dynamics of semiarid Mediterranean shrublands. We predict that the combined effect of both drivers will be additive or synergistic, increasing the negative effects of each one. We compared vegetation and soil properties of flat areas (low erosion) and steep hillslopes (high erosion) in two climatic areas (484 mm and 10.3°C, and 368mm and 11.9°C, respectively) that reproduce the predicted climate change in temperature and precipitation for the next 40 years. Species richness, vegetal cover, plant life-form composition were determined in 20 m2 plots and soil was sampled in the same plots to determine bulk density, aggregate stability, fertility and water holding capacity. All soil and vegetation properties were negatively affected by soil erosion and climate change. However, contrary to our hypothesis, the joined effect of both drivers on all soil and vegetation properties was antagonistic, except for the vegetal cover that showed an additive response to their interaction. Our results evidence that soil erosion affects more negatively the soil and vegetation properties in the cooler and

  20. The fate of exogenous iodine in pot soil cultivated with vegetables.

    PubMed

    Hong, Chun-lai; Weng, Huan-xin; Yan, Ai-lan; Islam, Ejaz-ul

    2009-02-01

    A pot experiment was conducted to explore a more effective approach to enhancing vegetable uptake of soil iodine, with the ultimate goal of using agricultural fortification as a measure to prevent iodine deficiency disorders in local communities. Two types of iodine fertilizers were added separately to pot soil samples at various dosages. The fortified soil in each of the flower pots was seeded with one of four test crops (pakchoi, celery, pepper, and radish) in an effort to examine the effect of vegetable cultivation. The fate and residual levels of the exogenous iodine in the fortified soil samples were then monitored and quantified. The data showed that the soil iodine contents decreased with time (and hence with plant growth as well). At the second cutting, iodine from the inorganic form (KI) as the exogenous source was reduced to approximately 50% (41.6-61.0%) of the applied dose, whereas that in soil fortified with the seaweed fertilizer was down to approximately 60% (53.9-71.5%). The abilities of the edible portion of the four vegetables in accumulating the soil iodine were as follows: pakchoi > celery > radish > pepper. On the whole, iodine residues were found less in soil cultivated with vegetables. Vegetable cultivation appeared to have enhanced the soil content of the water-soluble form of iodine somewhat, especially in soil fortified with the inorganic forms. There also appeared to be a significant negative correlation between the residual iodine and its dissolution rate in soil. Overall, the results of the present study pointed toward the direction that the seaweed fertilizer tends to be a (more) preferred source of agricultural fortification in promoting human iodine nutrition.

  1. Relative skills of soil moisture and vegetation optical depth retrievals for agricultural drought monitoring

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil moisture condition is an important indicator for agricultural drought monitoring. Through the Land Parameter Retrieval Model (LPRM), vegetation optical depth (VOD) as well as surface soil moisture (SM) can be retrieved simultaneously from brightness temperature observations from the Advanced Mi...

  2. [Characteristics of soil microelements contents in the rhizospheres of different vegetation in hilly-gully region of Loess Plateau].

    PubMed

    Zhang, Chao; Liu, Guo-Bin; Xue, Sha; Zhang, Chang-Sheng

    2012-03-01

    To explore the rhizosphere effect of the microelements in the soils under different vegetation types in Loess Plateau, this paper analyzed the organic C, total N, Mn, Cu, Fe, and Zn contents in the rhizosphere soil and bulk soil of six vegetation types in hilly-gully region of Loess Plateau. Among the six vegetation types, Caragana korshinskii, Heteropappus altaicus, and Artemisia capillaries had higher organic C and total N contents in rhizosphere soil than in bulk soil. With the exception of C. korshinskii and H. rhamnoides, all the six vegetation types had a significantly lower pH in rhizosphere soil than in bulk soil. The six vegetation types had a lower available Mn content in rhizosphere soil than in bulk soil, and the C. korshinskii, Astragalus adsurgen, and Panicum virgatum had a significantly higher available Cu content in rhizosphere soil than in bulk soil. The six vegetation types except A. adsurgens had a slightly higher available Fe content in rhizosphere soil than in bulk soil, and A. adsurgens, P. virgatum, H. altaicus, and A. capillaries had a significant accumulation of available Zn in rhizosphere soil. There existed significant positive correlations between the rhizosphere soil and bulk soil of the six vegetation types in the relationships between the organic C and total N contents and the available Mn and Zn contents and between the contents of available Mn and Zn. In rhizosphere soil, available Mn and Zn contents were significantly negative- ly correlated with pH value. Due to the differences in root growth characteristics, rhizosphere pH value, and microbial structure composition, the microelements contents in the rhizosphere soil of the six vegetation types differed, with the contents of Mn, Cu, Fe, and Zn being higher in the rhizosphere soil of H. altaicus than in that of the other vegetation types.

  3. [Characteristics of soil pH and exchangeable acidity in red soil profile under different vegetation types].

    PubMed

    Ji, Gang; Xu, Ming-gang; Wen, Shi-lin; Wang, Bo-ren; Zhang, Lu; Liu, Li-sheng

    2015-09-01

    The characteristics of soil pH and exchangeable acidity in soil profile under different vegetation types were studied in hilly red soil regions of southern Hunan Province, China. The soil samples from red soil profiles within 0-100 cm depth at fertilized plots and unfertilized plots were collected and analyzed to understand the profile distribution of soil pH and exchangeable acidity. The results showed that, pH in 0-60 cm soil from the fertilized plots decreased as the following sequence: citrus orchard > Arachis hypogaea field > tea garden. As for exchangeable acidity content, the sequence was A. hypogaea field ≤ citrus orchard < tea garden. After tea tree and A. hypogaea were planted for long time, acidification occurred in surface soil (0-40 cm), compared with the deep soil (60-100 cm), and soil pH decreased by 0.55 and 0.17 respectively, but such changes did not occur in citrus orchard. Soil pH in 0-40 cm soil from the natural recovery vegetation unfertilized plots decreased as the following sequence: Imperata cylindrica land > Castanea mollissima garden > Pinus elliottii forest ≥ Loropetalum chinensis forest. As for exchangeable acidity content, the sequence was L cylindrica land < C. mollissima garden < L. chinensis forest ≤ P. elliottii forest. Soil pH in surface soil (0-20 cm) from natural forest plots, secondary forest and Camellia oleifera forest were significantly lower than that from P. massoniana forest, decreased by 0.34 and 0.20 respectively. For exchangeable acidity content in 0-20 cm soil from natural forest plot, P. massoniana forest and secondary forest were significantly lower than C. oleifera forest. Compared with bare land, surface soil acidification in unfertilized plots except I. cylindrica land had been accelerated, and the natural secondary forest was the most serious among them, with surface soil pH decreasing by 0.52. However, the pH increased in deep soils from unfertilized plots except natural secondary forest, and I. cylindrica

  4. Influence of Vegetations' Metabolites on the Composition and Functioning of Soil Microbial Complex

    NASA Astrophysics Data System (ADS)

    Biryukov, Mikhail

    2013-04-01

    Microbiota is one of the major factors of soils fertility. It transforms organic substances in soil and, therefore, serves as the main component in the cycles of carbon and nitrogen. Microbial communities (MC) are characterized as highly diverse and extremely complex structures. This allows them to adapt to any affection and provide all the necessary biospheric functions. Hence, the study of their functional diversity and adaptivity of microbiota provides the key to the understanding of the ecosystems' functioning and their adaptivity to the human impact. The formation of MC at the initial stage is regulated by the fluxes of substrates and biologically active substances (BAS), which vary greatly in soils under different vegetations. These fluxes are presented by: low molecular weights organic substances (LMWOS), which can be directly included in metabolism of microbes; polymers, that can be decomposed to LMWOS by exoenzymes; and more complex compounds, having different "drug effects" (e.g. different types of phenolic acids) and regulating growth and enzymatic properties of microbiota. Therefore, the main hypothesis of the research was formulated as follows: penetration of different types of substrates and BAS into soil leads to the emergence of MC varying in enzymatic properties and structure. As a soil matrix we used the soil from the untreated variant of the lysimeter model experiment taking place in the faculty of Soil Science of the MSU for over the last 40 years. It was sieved with a 2mm sieves, humidified and incubated at 25C during one week. Subsequently, the samples were air-dried with occasional stirring for one more week. Thereafter, aliquots of the prepared soil were taken for the different experimental variants. The samples were rewetted with solutions of various substrates (glucose, cellulose, starch, etc.) and thoroughly mixed. The control variant was established with addition of deionised water. The samples were incubated at the 25C. During the

  5. Soil moisture inferences from thermal infrared measurements of vegetation temperatures

    NASA Technical Reports Server (NTRS)

    Jackson, R. D. (Principal Investigator)

    1981-01-01

    Thermal infrared measurements of wheat (Triticum durum) canopy temperatures were used in a crop water stress index to infer root zone soil moisture. Results indicated that one time plant temperature measurement cannot produce precise estimates of root zone soil moisture due to complicating plant factors. Plant temperature measurements do yield useful qualitative information concerning soil moisture and plant condition.

  6. Remote measurement of soil moisture over vegetation using infrared temperature measurements

    NASA Technical Reports Server (NTRS)

    Carlson, Toby N.

    1991-01-01

    Better methods for remote sensing of surface evapotranspiration, soil moisture, and fractional vegetation cover were developed. The objectives were to: (1) further develop a model of water movement through the soil/plant/atmosphere system; (2) use this model, in conjunction with measurements of infrared surface temperature and vegetation fraction; (3) determine the magnitude of radiometric temperature response to water stress in vegetation; (4) show at what point one can detect that sensitivity to water stress; and (5) determine the practical limits of the methods. A hydrological model that can be used to calculate soil water content versus depth given conventional meteorological records and observations of vegetation cover was developed. An outline of the results of these initiatives is presented.

  7. Effect of vegetation on rock and soil type discrimination

    NASA Technical Reports Server (NTRS)

    Siegal, B. S.; Goetz, A. F. H.

    1977-01-01

    The effect of naturally occurring vegetation on the spectral reflectance of earth materials in the wavelength region of 0.45 to 2.4 microns is determined by computer averaging of in situ acquired spectral data. The amount and type of vegetation and the spectral reflectance of the ground are considered. Low albedo materials may be altered beyond recognition with only ten per cent green vegetation cover. Dead or dry vegetation does not greatly alter the shape of the spectral reflectance curve and only changes the albedo with minimum wavelength dependency. With increasing amounts of vegetation the Landsat MSS band ratios 4/6, 4/7, 5/6, and 5/7 are significantly decreased whereas MSS ratios 4/5 and 6/7 remain entirely constant.

  8. Comparisons among a new soil index and other two- and four-dimensional vegetation indices

    NASA Technical Reports Server (NTRS)

    Wiegand, C. L.; Richardson, A. J.

    1982-01-01

    The 2-D difference vegetation index (DVI) and perpendicular vegetation index (PVI), and the 4-D green vegetation index (GVI) are compared in Landsat MSS data from grain sorghum (Sorghum bicolor, L. Moench) fields for the years 1973 to 1977. PVI and DVI were more closely related to LAI than was GVI. A new 2-D soil line index (SLI), the vector distance from the soil line origin to the point of intersection of PVI with the soil line, is defined and compared with the 4-D soil brightness index, SBI. SLI (based on MSS and MSS7) and SL16 (based on MSS5 and MSS6) were smaller in magnitude than SBI but contained similar information about the soil background. These findings indicate that vegetation and soil indices calculated from the single visible and reflective infrared band sensor systems, such as the AVHRR of the TIROS-N polar orbiting series of satellites, will be meaningful for synoptic monitoring of renewable vegetation. Previously announced in STAR as N83-14567

  9. Comparisons among a new soil index and other two- and four-dimensional vegetation indices

    NASA Technical Reports Server (NTRS)

    Wiegand, C. L.; Richardson, A. J. (Principal Investigator)

    1982-01-01

    The 2-D difference vegetation index (DVI) and perpendicular vegetation index (PVI), and the 4-D green vegetation index (GVI) are compared in LANDSAT MSS data from grain sorghum (Sorghum bicolor, L. Moench) fields for the years 1973 to 1977. PVI and DVI were more closely related to LAI than was GVI. A new 2-D soil line index (SLI), the vector distance from the soil line origin to the point of intersection of PVI with the soil line, is defined and compared with the 4-D soil brightness index, SBI. SLI (based on MSS and MSS7) and SL16 (based on MSS 5 and MSS 6) were smaller in magnitude than SBI but contained similar information about the soil background. These findings indicate that vegetation and soil indices calculated from the single visible and reflective infrared band sensor systems, such as the AVHRR of the TIROS-N polar orbiting series of satellites, will be meaningful for synoptic monitoring of renewable vegetation.

  10. Can artificial soil be used in the vegetative vigor test for U.S. pesticide registration?

    PubMed

    Bidelspach, Conor; Olszyk, David; Pfleeger, Thomas

    2008-10-01

    Current testing guidelines for pesticide registration for the protection of nontarget plants calls for the use of sterilized, standardized soil consisting of primarily sandy loam, loamy sand, loamy clay, or clay loam that contains up to 3% organic matter. Low organic matter soils can be difficult to manage in a greenhouse setting because when soils dry, they contract, causing impeded water infiltration, or when overwatered, poor drainage increases the chances of anaerobic conditions. The purpose of this study was to determine if the results for the vegetative vigor test differed when using either natural or artificial soils. The herbicide sulfometuron methyl was applied 14 d after emergence at 0.1 and 0.0032 of the suggested field application rate. Six plant species were tested, 4 of the common test species, Zea mays (corn), Glycine max (soybean), Avena sativa (oat), and Lactuca sativa (lettuce), and 2 native plants of the Willamette Valley, Oregon prairie, Bromus carinatus (California brome) and Ranunculus occidentalis (western buttercup). Herbicide application rate was the most significant factor in the experiment regardless of soil type. The different soils generally produced different results, even though the 2 native soils, one from Oregon and the other from Maryland, are both acceptable soils for the pesticide registration tests. The plants grown on artificial soil produced results generally between the Oregon and Maryland soil results. This study indicates that artificial soils may produce results similar to or more sensitive than soils currently used in the vegetative vigor test.

  11. An overview of research on the beneficial effects of vegetation in contaminated soil.

    PubMed

    Erickson, L E

    1997-11-21

    Vegetation can enhance in situ bioremediation processes in many applications. Microbial transformations occur in soil and water external to plant roots. Organic contaminants also enter vegetation and are transformed within plants. Research progress is reviewed with emphasis on recent experimental results and mathematical models of contaminant fate in systems where vegetation is present. Plant evapotranspiration provides a solar driven pump-and-treat system which moves contaminants to the rhizosphere and helps to contain them on site. Significant savings have been reported at several field sites where vegetation has been utilized.

  12. [Characteristics of soil nematode communities in coastal wetlands with different vegetation types].

    PubMed

    Liu, Bei-Bei; Ye, Cheng-Long; Yu, Li; Jiao, Jia-Guo; Liu, Man-Qiang; Hu, Feng; Li, Hui-Xin

    2012-11-01

    An investigation was conducted on the characteristics of soil nematode communities in different vegetation belts (Spartina alterniflora belt, Sa; Suaeda glauca belt, Sg; bare land, B1; Phragmites australis belt, Pa; and wheat land, Wl) of Yancheng Wetland Reserve, Jiangsu Province of East China. A total of 39 genera and 20 families of soil nematodes were identified, and the individuals of dominant genera and common genera occupied more than 90% of the total. The total number of the nematodes differed remarkably with vegetation belts, ranged from 79 to 449 individuals per 100 grams of dry soil. Wheat land had the highest number of soil nematodes, while bare land had the lowest one. The nematode ecological indices responded differently to the vegetation belts. The Shannon index (H) and evenness index (J) decreased in the order of Pa > Sg > Wl > Sa > Bl, and the dominance index (lambda) was in the order of Bl > Sa > Wl > Sg > Pa, suggesting that the diversity and stability of the nematode community in bare land were lower than those in the other vegetation belts, and the nematode community in the bare land tended to be simplified. The maturity index (MI) was higher in uncultivated vegetation belts than in wheat land, suggesting that the wheat land was disturbed obviously. The nematode community structure differed significantly with vegetation belts, and the main contributing species in different vegetation belts also differed. There existed significant correlations between the soil physical and chemical characteristics and the nematode numbers, trophic groups, and ecological indices. Our results demonstrated that the changes of soil nematode community structure could be used as an indicator well reflecting the diversity of vegetation belt habitat, and an important bio-indicator of coastal wetland ecosystem.

  13. Soil erosion-vegetation interactions in Mediterranean-dry reclaimed mining slopes

    NASA Astrophysics Data System (ADS)

    Moreno de las Heras, Mariano; Merino-Martín, Luis; Espigares, Tíscar; Nicolau, José M.

    2014-05-01

    Mining reclamation in Mediterranean-dry environments represents a complex task. Reclaimed mining slopes are particularly vulnerable to the effects of accelerated soil erosion processes, especially when these processes lead to the formation of rill networks. On the other hand, encouraging early vegetation establishment is perceived as indispensable to reduce the risk of degradation in these man-made ecosystems. This study shows a synthesis of soil erosion-vegetation research conducted in reclaimed mining slopes at El Moral field site (Teruel coalfield, central-east Spain). Our results highlight the role of rill erosion processes in the development of reclaimed ecosystems. Runoff routing is conditioned by the development of rill networks, maximizing the loss of water resources at the slope scale by surface runoff and altering the spatial distribution of soil moisture. As a result, the availability of water resources for plant growth is drastically reduced, affecting vegetation development. Conversely, vegetation exerts a strong effect on soil erosion: erosion rates rapidly decrease with vegetation cover and no significant rill erosion is usually observed after a particular cover threshold is reached. These interactive two-way vegetation-soil erosion relationships are further studied using a novel modeling approach that focuses on stability analysis of water-limited reclaimed slopes. Our framework reproduces two main groups of trends along the temporal evolution of reclaimed slopes: successful trends, characterized by widespread vegetation development and the effective control of rill erosion processes; and gullying trends, characterized by the progressive loss of vegetation and a sharp logistic increase in erosion rates. This stability-analysis also facilitates the determination of threshold values for both vegetation cover and rill erosion that drive the long-term reclamation results, assisting the identification of critical situations that require specific human

  14. A time-series approach to estimating soil moisture from vegetated surfaces using L-band radar backscatter

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many previous studies have shown the sensitivity of radar backscatter to surface soil moisture content, particularly at L-band. Moreover, the estimation of soil moisture from radar for bare soil surfaces is well-documented, but estimation underneath a vegetation canopy remains unsolved. Vegetation s...

  15. [Soil microbial properties under different vegetation types in Loess hilly region].

    PubMed

    Zhang, Yan-Yan; Qu, Lai-Ye; Chen, Li-Ding; Wei, Wei

    2010-01-01

    By using fumigation-extract (FE) method and Biolog Ecoplate, this paper investigated the microbial biomass and diversity in 0-20 cm soil layer under five vegetation types, including artificial woodland, shrubland, cropland, abandoned farmland, and natural grassland, in Dingxi of Gansu Province. In the meanwhile, the relationships between soil microbes and soil nutrients were studied by path analysis, and the five typical vegetation types were evaluated from the aspect of soil microbes. Relative to cropland, "grain for green" project played a key role in improving soil microbial resources. Microbial biomass carbon was the highest in ridge grassland, abandoned farmland, and pine woodland, followed by in Caragana korshinskii land, Medicago sativa land, restored land, and roadside land, and in wheat field and potato field. Microbial biomass nitrogen was the highest in ridge land, abandoned farmland, Pinus tabulaeformis woodland, Caragana korshinskii land, and Medicago sativa land, followed by in restored land and roadside land, and in wheat field and potato field. Caragana korshinskii land and Medicago sativa land, due to the existence of N-fixing rhizobium, had the highest ratio of soil microbial biomass nitrogen to soil total nitrogen. Owing to the continual biomass loss and rare feedback, cropland had the lowest quantity and activity of soil microbes. Through planting trees, shrubs and grasses or through fallowing, soil microbial biomass and activity were recovered, and the effect was increased with time. In 20-year old Caragana korshinskii land, the quantity and activity of soil microbes were similar to those in 50-year old Pinus tabulaeformis woodland, and the microbial community catabolic activity and soil nutrient use efficiency were higher. Considering the features of soil microbes under test vegetation types, Caragana korshinskii would be a good choice for local vegetation restoration.

  16. Investigation of Soil and Vegetation Characteristics in Discontinuous Permafrost Landscapes Near Fairbanks, Alaska

    DTIC Science & Technology

    2015-08-01

    soil carbon and nitrogen concentrations increased in low microtopographic positions. These results suggest that soil and vegetation conditions may...Ranging N Nitrogen NRCS Natural Resources Conservation Service OBL Obligate Wetland Pt Platinum PT ERDC Permafrost Tunnel UPL Obligate Upland USACE...1,28) = 7.96; p = 0.009—and nitrogen (U = 51.5; p = 0.010) concentrations in low microtopographic positions. These results suggest that soil and

  17. Soil and vegetation response to soil compaction and forest floor removal after aspen harvesting. Forest Service research paper

    SciTech Connect

    Alban, D.H.; Host, G.E.; Elioff, J.D.; Shadis, D.

    1994-01-01

    Reduced soil porosity and organic matter removal have been identified as common factors associated with loss of forest productivity (Powers et al. 1990). In both agriculture and forestry, management activities can modify soil porosity and organic matter with resultant impacts on vegetative growth. As part of a nationwide long-term soil productivity (LTSP) study soil porosity and organic matter are being experimentally manipulated on large plots to determine the impacts of such manipulations on growth and species diversity for a wide range of forest types.

  18. Roadside vegetation barrier designs to mitigate near-road air pollution impacts.

    PubMed

    Tong, Zheming; Baldauf, Richard W; Isakov, Vlad; Deshmukh, Parikshit; Zhang, K Max

    2016-01-15

    With increasing evidence that exposures to air pollution near large roadways increases risks of a number of adverse human health effects, identifying methods to reduce these exposures has become a public health priority. Roadside vegetation barriers have shown the potential to reduce near-road air pollution concentrations; however, the characteristics of these barriers needed to ensure pollution reductions are not well understood. Designing vegetation barriers to mitigate near-road air pollution requires a mechanistic understanding of how barrier configurations affect the transport of traffic-related air pollutants. We first evaluated the performance of the Comprehensive Turbulent Aerosol Dynamics and Gas Chemistry (CTAG) model with Large Eddy Simulation (LES) to capture the effects of vegetation barriers on near-road air quality, compared against field data. Next, CTAG with LES was employed to explore the effects of six conceptual roadside vegetation/solid barrier configurations on near-road size-resolved particle concentrations, governed by dispersion and deposition. Two potentially viable design options are revealed: a) a wide vegetation barrier with high Leaf Area Density (LAD), and b) vegetation-solid barrier combinations, i.e., planting trees next to a solid barrier. Both designs reduce downwind particle concentrations significantly. The findings presented in the study will assist urban planning and forestry organizations with evaluating different green infrastructure design options.

  19. A multi-frequency radiometric measurement of soil moisture content over bare and vegetated fields

    NASA Technical Reports Server (NTRS)

    Wang, J. R.; Schmugge, T. J.; Gould, W. I.; Glazar, W. S.; Fuchs, J. E.; Mcmurtrey, J. E., III

    1982-01-01

    An experiment on soil moisture remote sensing was conducted during July to September 1981 on bare, grass, and alfalfa fields at frequencies of 0.6, 1.4, 5.0, and 10.6 GHz with radiometers mounted on mobile towers. The results confirm the frequency dependence of sensitivity reduction due to the presence of vegetation cover. For the type of vegetated fields reported here, the vegetation effect is appreciable even at 0.6 GHz. Measurements over bare soil show that when the soil is wet, the measured brightness temperature is lowest at 5.0 GHz and highest at 0.6 GHz, a result contrary to the expectation based on the estimated dielectric permittivity of soil-water mixtures and the current radiative transfer model in that frequency range.

  20. [Evaluation and source analysis of the mercury pollution in soils and vegetables around a large-scale zinc smelting plant].

    PubMed

    Liu, Fang; Wang, Shu-Xiao; Wu, Qing-Ru; Lin, Hai

    2013-02-01

    The farming soil and vegetable samples around a large-scale zinc smelter were collected for mercury content analyses, and the single pollution index method with relevant regulations was used to evaluate the pollution status of sampled soils and vegetables. The results indicated that the surface soil and vegetables were polluted with mercury to different extent. Of the soil samples, 78% exceeded the national standard. The mercury concentration in the most severely contaminated area was 29 times higher than the background concentration, reaching the severe pollution degree. The mercury concentration in all vegetable samples exceeded the standard of non-pollution vegetables. Mercury concentration, in the most severely polluted vegetables were 64.5 times of the standard, and averagely the mercury concentration in the vegetable samples was 25.4 times of the standard. For 85% of the vegetable samples, the mercury concentration, of leaves were significantly higher than that of roots, which implies that the mercury in leaves mainly came from the atmosphere. The mercury concentrations in vegetable roots were significantly correlated with that in soils, indicating the mercury in roots was mainly from soil. The mercury emissions from the zinc smelter have obvious impacts on the surrounding soils and vegetables. Key words:zinc smelting; mercury pollution; soil; vegetable; mercury content

  1. Vegetation cover and land use impacts on soil water repellency in an Urban Park located in Vilnius, Lithuania

    NASA Astrophysics Data System (ADS)

    Pereira, Paulo; Cerda, Artemi

    2015-04-01

    It is strongly recognized that vegetation cover, land use have important impacts on the degree of soil water repellency (SWR). Soil water repellency is a natural property of soils, but can be induced by natural and anthropogenic disturbances as fire and soil tillage (Doerr et al., 2000; Urbanek et al., 2007; Mataix-Solera et al., 2014). Urban parks are areas where soils have a strong human impact, with implications on their hydrological properties. The aim of this work is to study the impact of different vegetations cover and urban soils impact on SWR and the relation to other soil variables as pH, Electrical Conductivity (EC) and soil organic matter (SOM) in an urban park. The study area is located in Vilnius city (54°.68' N, 25°.25' E). It was collected 15 soil samples under different vegetation cover as Pine (Pinus Sylvestris), Birch (Alnus glutinosa), Penduculate Oak (Quercus robur), Platanus (Platanus orientalis) and other human disturbed areas as forest trails and soils collected from human planted grass. Soils were taken to the laboratory, air-dried at room temperature and sieved with the <2 mm mesh in order to remove the coarse material. Subsequently were placed in petri dishes and exposed to a controlled laboratory environment (temperature of 20C and 50% of air relative humidity) for one week to avoid potential impacts of the atmospheric conditions on SWR (Doerr, 1998). The persistence of SWR was measured using the water drop penetration time (WDPT) (Wessel, 1998). The classification of WDPT was according to Bisdom et al. (1993) <5 (wettable), 5-60 (slightly water repellent), 60-600 (strongly water repellent), 600-3600 (severely water repellent) and >3600 (extremely water repellent). The results showed significant differences among the different vegetation cover (Kruskal-Wallis H=20.64, p<0.001). The WDPT soil median values collected under Pine, Birch, Penduculate Oak, forest trails and soils from planted grass were significantly higher than Platanus

  2. Integrated Field Lysimetry and Porewater Sampling for Evaluation of Chemical Mobility in Soils and Established Vegetation

    PubMed Central

    Gannon, Travis W.; Polizzotto, Matthew L.

    2014-01-01

    Potentially toxic chemicals are routinely applied to land to meet growing demands on waste management and food production, but the fate of these chemicals is often not well understood. Here we demonstrate an integrated field lysimetry and porewater sampling method for evaluating the mobility of chemicals applied to soils and established vegetation. Lysimeters, open columns made of metal or plastic, are driven into bareground or vegetated soils. Porewater samplers, which are commercially available and use vacuum to collect percolating soil water, are installed at predetermined depths within the lysimeters. At prearranged times following chemical application to experimental plots, porewater is collected, and lysimeters, containing soil and vegetation, are exhumed. By analyzing chemical concentrations in the lysimeter soil, vegetation, and porewater, downward leaching rates, soil retention capacities, and plant uptake for the chemical of interest may be quantified. Because field lysimetry and porewater sampling are conducted under natural environmental conditions and with minimal soil disturbance, derived results project real-case scenarios and provide valuable information for chemical management. As chemicals are increasingly applied to land worldwide, the described techniques may be utilized to determine whether applied chemicals pose adverse effects to human health or the environment. PMID:25045915

  3. Integrated field lysimetry and porewater sampling for evaluation of chemical mobility in soils and established vegetation.

    PubMed

    Matteson, Audrey R; Mahoney, Denis J; Gannon, Travis W; Polizzotto, Matthew L

    2014-07-04

    Potentially toxic chemicals are routinely applied to land to meet growing demands on waste management and food production, but the fate of these chemicals is often not well understood. Here we demonstrate an integrated field lysimetry and porewater sampling method for evaluating the mobility of chemicals applied to soils and established vegetation. Lysimeters, open columns made of metal or plastic, are driven into bareground or vegetated soils. Porewater samplers, which are commercially available and use vacuum to collect percolating soil water, are installed at predetermined depths within the lysimeters. At prearranged times following chemical application to experimental plots, porewater is collected, and lysimeters, containing soil and vegetation, are exhumed. By analyzing chemical concentrations in the lysimeter soil, vegetation, and porewater, downward leaching rates, soil retention capacities, and plant uptake for the chemical of interest may be quantified. Because field lysimetry and porewater sampling are conducted under natural environmental conditions and with minimal soil disturbance, derived results project real-case scenarios and provide valuable information for chemical management. As chemicals are increasingly applied to land worldwide, the described techniques may be utilized to determine whether applied chemicals pose adverse effects to human health or the environment.

  4. Interactive effects of soil temperature, atmospheric carbon dioxide and soil N on root development, biomass and nutrient uptake of winter wheat during vegetative growth.

    PubMed

    Gavito, M E; Curtis, P S; Mikkelsen, T N; Jakobsen, I

    2001-09-01

    Nutrient requirements for plant growth are expected to rise in response to the predicted changes in CO(2) and temperature. In this context, little attention has been paid to the effects of soil temperature, which limits plant growth at early stages in temperate regions. A factorial growth-room experiment was conducted with winter wheat, varying soil temperature (10 degrees C and 15 degrees C), atmospheric CO(2) concentration (360 and 700 ppm), and N supply (low and high). The hypothesis was that soil temperature would modify root development, biomass allocation and nutrient uptake during vegetative growth and that its effects would interact with atmospheric CO(2) and N availability. Soil temperature effects were confirmed for most of the variables measured and 3-factor interactions were observed for root development, plant biomass components, N-use efficiency, and shoot P content. Importantly, the soil temperature effects were manifest in the absence of any change in air temperature. Changes in root development, nutrient uptake and nutrient-use efficiencies were interpreted as counterbalancing mechanisms for meeting nutrient requirements for plant growth in each situation. Most variables responded to an increase in resource availability in the order: N supply >soil temperature >CO(2).

  5. Bacterial Community Responses to Soils along a Latitudinal and Vegetation Gradient on the Loess Plateau, China.

    PubMed

    Zeng, Quanchao; Dong, Yanghong; An, Shaoshan

    2016-01-01

    Soil bacterial communities play an important role in nutrient recycling and storage in terrestrial ecosystems. Loess soils are one of the most important soil resources for maintaining the stability of vegetation ecosystems and are mainly distributed in northwest China. Estimating the distributions and affecting factors of soil bacterial communities associated with various types of vegetation will inform our understanding of the effect of vegetation restoration and climate change on these processes. In this study, we collected soil samples from 15 sites from north to south on the Loess Plateau of China that represent different ecosystem types and analyzed the distributions of soil bacterial communities by high-throughput 454 pyrosequencing. The results showed that the 142444 sequences were grouped into 36816 operational taxonomic units (OTUs) based on 97% similarity. The results of the analysis showed that the dominant taxonomic phyla observed in all samples were Actinobacteria, Proteobacteria, Chloroflexi, Acidobacteria and Planctomycetes. Actinobacteria and Proteobacteria were the two most abundant groups in all samples. The relative abundance of Actinobacteria increased from 14.73% to 40.22% as the ecosystem changed from forest to sandy, while the relative abundance of Proteobacteria decreased from 35.35% to 21.40%. Actinobacteria and Proteobacteria had significant correlations with mean annual precipitation (MAP), pH, and soil moisture and nutrients. MAP was significantly correlated with soil chemical and physical properties. The relative abundance of Actinobacteria, Proteobacteria and Planctomycetes correlated significantly with MAP, suggesting that MAP was a key factor that affected the soil bacterial community composition. However, along with the MAP gradient, Chloroflexi, Bacteroidetes and Cyanobacteria had narrow ranges that did not significantly vary with the soil and environmental factors. Overall, we conclude that the edaphic properties and/or vegetation

  6. Bacterial Community Responses to Soils along a Latitudinal and Vegetation Gradient on the Loess Plateau, China

    PubMed Central

    Zeng, Quanchao; Dong, Yanghong; An, Shaoshan

    2016-01-01

    Soil bacterial communities play an important role in nutrient recycling and storage in terrestrial ecosystems. Loess soils are one of the most important soil resources for maintaining the stability of vegetation ecosystems and are mainly distributed in northwest China. Estimating the distributions and affecting factors of soil bacterial communities associated with various types of vegetation will inform our understanding of the effect of vegetation restoration and climate change on these processes. In this study, we collected soil samples from 15 sites from north to south on the Loess Plateau of China that represent different ecosystem types and analyzed the distributions of soil bacterial communities by high-throughput 454 pyrosequencing. The results showed that the 142444 sequences were grouped into 36816 operational taxonomic units (OTUs) based on 97% similarity. The results of the analysis showed that the dominant taxonomic phyla observed in all samples were Actinobacteria, Proteobacteria, Chloroflexi, Acidobacteria and Planctomycetes. Actinobacteria and Proteobacteria were the two most abundant groups in all samples. The relative abundance of Actinobacteria increased from 14.73% to 40.22% as the ecosystem changed from forest to sandy, while the relative abundance of Proteobacteria decreased from 35.35% to 21.40%. Actinobacteria and Proteobacteria had significant correlations with mean annual precipitation (MAP), pH, and soil moisture and nutrients. MAP was significantly correlated with soil chemical and physical properties. The relative abundance of Actinobacteria, Proteobacteria and Planctomycetes correlated significantly with MAP, suggesting that MAP was a key factor that affected the soil bacterial community composition. However, along with the MAP gradient, Chloroflexi, Bacteroidetes and Cyanobacteria had narrow ranges that did not significantly vary with the soil and environmental factors. Overall, we conclude that the edaphic properties and/or vegetation

  7. [Contribution of soil seed bank to the regeneration of damaged vegetation on floodplain].

    PubMed

    Wang, Zeng-ru; Xu, Hai-liang; Yin, Lin-ke; Li, Ji-mei; Zhang, Zhan-jiang; Li, Yuan

    2008-12-01

    A field germination experiment of soil seed bank was carried out on two typical floodplains in the lower reaches of Tarim River, and a comparison was made between the soil seed banks and corresponding seedling banks on the two floodplains, aimed to assess the contribution of soil seed bank to the regeneration of damaged vegetation. The results showed that there were 12 plant species in the soil seed banks, and the life forms were mainly perennial herbs and shrubs. The soil seed banks had a density of 282.5 seeds m(-2) and 173.2 seeds x m(-2), and the seeds in top soil (0-2 cm) accounted for 76.9% and 71.0% of the total, respectively. The soil seed banks had significant effects on the seedlings species composition and density, and 84.7% and 99.4% of the seedlings on the two floodplains were emerged from corresponding soil seed banks. The similarity coefficient between soil seed bank and seedling bank of the two floodplains was 0.72 and 0.63, respectively, and there existed significant positive correlation between seedling density and soil seed bank density, illustrating that soil seed bank made important contribution to the natural regeneration of vegetation.

  8. Uptake of 137Cs by Leafy Vegetables and Grains from Calcareous Soils

    SciTech Connect

    Robison, W; Hamilton, T; Conrado, C; Kehl, S

    2004-04-19

    Cesium-137 was deposited on Bikini Island at Bikini Atoll in 1954 as a result of nuclear testing and has been transported and cycled in the ecosystem ever since. Atoll soils are of marine origin and are almost pure CaCO{sub 3} with high concentrations of organic matter in the top 40 cm. Data from previous experiments with mature fruit trees show very high transfer factors (TF's), [Bq g{sup -1} plant/ Bq g{sup -1} soil, both in dry weight] into fruits from atoll calcareous soil. These TF's are much higher than reported for continental, silica-based soils. In this report TF's for 5 types of leafy vegetable crops and 2 types of grain crops are provided for use in predictive dose assessments and for comparison with other data from other investigators working with other types of soil in the IAEA CRP ''The Classification of Soil Systems on the Basis of Transfer Factors of Radionuclides from Soil to Reference Plants''. Transfer factors for plants grown on calcareous soil are again very high relative to clay-containing soils and range from 23 to 39 for grain crops and 21 to 113 for leafy vegetables. Results from these experiments, in this unique, high pH, high organic content, low potassium (K) soil, provide a boundary condition for models relating soil properties to TF.

  9. [Study on nutrient and salinity in soil covered with different vegetations in Shuangtaizi estuarine wetlands].

    PubMed

    Song, Xiao-Lin; Lü, Xian-Guo; Zhang, Zhong-Sheng; Chen, Zhi-Ke; Liu, Zheng-Mao

    2011-09-01

    Nutrient elements and salinity in soil covered by different vegetations including Phragmites australis (Clay.) Trin., Typha orientalis Presl., Puccinellia distans Parl, and Suaeda salsa in Shuangtaizi estuarine wetlands were investigated to study their distribution characteristics and to reveal the nutrient element variation during the vegetation succession processes. Results indicated that total potassium, total phosphorus and salinity were different significantly in soil between different plant communities while available phosphorus, total nitrogen, available nitrogen, available potassium, total sulfur, iron and soil organic carbon were different insignificantly. Correlation analysis suggested that soil organic carbon were related significantly to total nitrogen, available phosphorus, available potassium, which implied that decomposition of plant litter might be the mail source of soil nitrogen and available nutrient. Salinity was significantly related to total phosphorus and iron in soil. In Shuangtaizi estuarine wetland soil, ratios of carbon to nitrogen (R(C/N)) was in the range of 12.21-26.33 and the average value was 18.21, which was higher than 12.0. It indicated that soil organic carbon in Shuangtaizi estuarine mainly came from land but not ocean and plants contributed the most of soil organic matters. There was no significant difference in R(C/N) between soil from the four plant communities (F = 1.890, p = 0.151). R(C/N) was related significantly to sol salinity (r = 0.346 3, p = 0.035 8) and was increasing with soil salinity.

  10. Contribution of understorey vegetation and soil processes to boreal forest isoprenoid exchange

    NASA Astrophysics Data System (ADS)

    Mäki, Mari; Heinonsalo, Jussi; Hellén, Heidi; Bäck, Jaana

    2017-03-01

    Boreal forest floor emits biogenic volatile organic compounds (BVOCs) from the understorey vegetation and the heterogeneous soil matrix, where the interactions of soil organisms and soil chemistry are complex. Earlier studies have focused on determining the net exchange of VOCs from the forest floor. This study goes one step further, with the aim of separately determining whether the photosynthesized carbon allocation to soil affects the isoprenoid production by different soil organisms, i.e., decomposers, mycorrhizal fungi, and roots. In each treatment, photosynthesized carbon allocation through roots for decomposers and mycorrhizal fungi was controlled by either preventing root ingrowth (50 µm mesh size) or the ingrowth of roots and fungi (1 µm mesh) into the soil volume, which is called the trenching approach. Isoprenoid fluxes were measured using dynamic (steady-state flow-through) chambers from the different treatments. This study aimed to analyze how important the understorey vegetation is as a VOC sink. Finally, a statistical model was constructed based on prevailing temperature, seasonality, trenching treatments, understory vegetation cover, above canopy photosynthetically active radiation (PAR), soil water content, and soil temperature to estimate isoprenoid fluxes. The final model included parameters with a statistically significant effect on the isoprenoid fluxes. The results show that the boreal forest floor emits monoterpenes, sesquiterpenes, and isoprene. Monoterpenes were the most common group of emitted isoprenoids, and the average flux from the non-trenched forest floor was 23 µg m-2 h-1. The results also show that different biological factors, including litterfall, carbon availability, biological activity in the soil, and physico-chemical processes, such as volatilization and absorption to the surfaces, are important at various times of the year. This study also discovered that understorey vegetation is a strong sink of monoterpenes. The

  11. Assessing risk to human health from tropical leafy vegetables grown on contaminated urban soils.

    PubMed

    Nabulo, G; Young, S D; Black, C R

    2010-10-15

    Fifteen tropical leafy vegetable types were sampled from farmers' gardens situated on nine contaminated sites used to grow vegetables for commercial or subsistence consumption in and around Kampala City, Uganda. Trace metal concentrations in soils were highly variable and originated from irrigation with wastewater, effluent discharge from industry and dumping of solid waste. Metal concentrations in the edible shoots of vegetables also differed greatly between, and within, sites. Gynandropsis gynandra consistently accumulated the highest Cd, Pb and Cu concentrations, while Amaranthus dubius accumulated the highest Zn concentration. Cadmium uptake from soils with contrasting sources and severity of contamination was consistently lowest in Cucurbita maxima and Vigna unguiculata, suggesting these species were most able to restrict Cd uptake from contaminated soil. Concentrations of Pb and Cr were consistently greater in unwashed, than in washed, vegetables, in marked contrast to Cd, Ni and Zn. The risk to human health, expressed as a 'hazard quotient' (HQ(M)), was generally greatest for Cd, followed successively by Pb, Zn, Ni and Cu. Nevertheless, it was apparent that urban cultivation of leafy vegetables could be safely pursued on most sites, subject to site-specific assessment of soil metal burden, judicious choice of vegetable types and adoption of washing in clean water prior to cooking.

  12. Heavy metals and metalloid content in vegetables and soil collected from the gardens of Zagreb, Croatia.

    PubMed

    Puntarić, Dinko; Vidosavljević, Domagoj; Gvozdić, Vlatka; Puntarić, Eda; Puntarić, Ida; Mayer, Dijana; Bosnir, Jasna; Lasić, Dario; Jergović, Matijana; Klarić, Ivana; Vidosavljević, Marina; Krivdić, Ivancica

    2013-09-01

    Aim of this study was to determine concentration of Pb, Cd, As and Hg in green leafy vegetables and soil in the urban area of Zagreb, Croatia and to determine if there is a connection between the contamination of soil and vegetables. Green leafy vegetables and soil samples were taken from the gardens located in the outskirts of the city. Concentrations of Pb, Cd, As and Hg were determined by atomic absorption spectrometry; showing that average concentrations of metals and metalloids in vegetables and in soil, regardless of the location of sampling were below the maximum allowed concentration (MAC). The analysis determined that metal concentrations in only nine vegetable samples (9%) were above maximum allowed values prescribed by national and European legislation (three with higher concentrations of Pb, one with a higher concentration of Cd and five with higher concentrations of Hg). Concentrations of contaminants present in the analysed samples, in general, are lower than the ones published in similar studies. The final distribution and concentration of contaminants in vegetables of Zagreb, besides industry and traffic, is affected by the dominant wind direction.

  13. Groundwater decline, vegetation change, and surface soil stability in a semi-arid environment

    NASA Astrophysics Data System (ADS)

    Elmore, A. J.; Kaste, J. M.; Vest, K. R.

    2008-12-01

    Groundwater resources provide water to human populations within arid and semi-arid environments globally. In many regions, shallow groundwater has been overexploited, breaking a poorly understood link between above- and belowground processes in ecosystems dominated by groundwater dependent vegetation. Of particular importance are connections between groundwater and vegetation cover, soil resources, and surface soil stability. Although groundwater is thought to increase the risk of dust emissions from non- vegetated playas (a process that characterizes many of the dustiest places on earth) little is known regarding dust emissions from terrain covered by groundwater dependent vegetation. In a multi-year study of these effects in Owens Valley California, we are integrating field measurements of plant community composition, soil stability, and groundwater depth with remotely sensed measurements of vegetation cover with the goal of elucidating the processes behind ecosystem change in a groundwater dependent ecosystem. We have identified a strong non-linear response between vegetation cover from remote sensing and groundwater decline. This response includes a threshold in groundwater depth, which separates groundwater and precipitation driven vegetation dynamics. At sites where groundwater went below this threshold, a shift towards dominance by more deeply rooted shrub vegetation and unstable surface soils is qualitatively evident. Quantitative evidence from fallout radionuclide concentrations suggests that surface soil stability is lower in regions of groundwater decline, but there is significant within-site variability. Although fine sediments might be winnowed away, groundwater affected sites appear to be characterized by a reorganization of sediments from the inter-canopy zone, where more shallowly rooted grasses were once dominant, to the canopy zones surrounding deeper-rooted shrubs. Therefore, our preliminary finding is that the resource island desertification

  14. Influence of vegetation spatial heterogeneity on soil enzyme activity in burned Mediterranean areas

    NASA Astrophysics Data System (ADS)

    Mayor, Á. G.; Goirán, S.; Bautista, S.

    2009-04-01

    Mediterranean ecosystems are commonly considered resilient to wildfires. However, depending on fire severity and recurrence, post-fire climatic conditions and plant community type, the recovery rate of the vegetation can greatly vary. Often, the post-fire vegetation cover remains low and sparsely distributed many years after the wildfire, which could have profound impacts on ecosystem functioning. In this work, we studied the influence of vegetation patchiness on soil enzyme activity (acid phosphatase, β-glucosidase and urease), at the patch and landscape scales, in degraded dry Mediterranean shrublands affected by wildfires. At the patch scale, we assessed the variation in soil enzyme between bare soils and vegetation patches. At the landscape scale, we studied the relationships between soil enzyme activity and various landscape metrics (total patch cover, average interpatch length, average patch width, and patch density). The study was conducted in 19 sites in the Valencia Region (eastern Spain), which had been affected by large wildfires in 1991. Site selection aimed at capturing a wide range of the variability of post-fire plant recovery rates in Mediterranean areas. The activities of the three enzymes were significantly higher in soils under the vegetation canopies than in adjacent bare areas, which we attributed to the effect of plants on the soil amount of both enzyme substrates and enzymes. The differences between bare and plant microsites were larger in the case of the acid phosphatase and less marked for urease. The activity of acid phosphatase was also higher under patches of resprouter species than under patches of seeder species, probably due to the faster post-fire recovery and older age of resprouter patches in fire-prone ecosystems. Soil enzyme activities of β-glucosidase and urease in both bare soils and vegetation patches showed no relationships with any of the landscape metrics analysed. However, the activity of acid phosphatase increased

  15. Micaceous Soil Strength And Permeability Improvement Induced By Microbacteria From Vegetable Waste

    NASA Astrophysics Data System (ADS)

    Omar, R. C.; Roslan, R.; Baharuddin, I. N. Z.; Hanafiah, M. I. M.

    2016-11-01

    Green technology method using vegetable waste are introduced in this paper for improvement of phyllite residual soil from UNITEN, Campus. Residual soil from phyllite are known as micaceous soils and it give problem in managing the stability of the slope especially in wet and extensively dry seasons. Micaceous soil are collected using tube sampler technique and mixed with liquid contain microorganism from fermented vegetable waste name as vege-grout to form remolded sample. The remolded sample are classify as 15.0%, 17.5%, 20.00% and 22.5% based on different incremental percentages of vege-grout. The curing time for the sample are 7, 14, 21, 28, and 35 days before the tests were conducted. Observation of the effect of treatment shows 20.0% of liquid contain Bacillus pasteurii and Bacillus Subtilis with 21 days curing time is the optimum value in strengthening the soil and improve the permeability.

  16. Vegetation and soil recovery in wilderness campsites closed to visitor use

    USGS Publications Warehouse

    Stohlgren, Thomas J.; Parsons, David J.

    1986-01-01

    Recreational use of wilderness results in impacts to vegetation and soil in trails and campsites. Traditionally, campsite impact studies have compared campsites receiving various levels of use with unused control areas. Field studies in Sequoia National Park, California, indicate that the degree of impact to vegetation and soils also varies within campsites. The central areas of campsites, where trampling is concentrated, show lower plant species diversity, differences in relative species cover, more highly compacted soils, and lower soil nutrient concentrations than do peripheral, moderately trampled, and untrampled areas within the same campsite. Three years after closure to visitor use, the central areas show less increase in mean foliar plant cover, and soils remain more highly compacted than in previously moderately trampled areas of the same sites. Changes in relative species cover over time are used to assess both resiliency to trampling and species composition recovery within campsites closed to visitor use.

  17. Measuring and Modelling water related soil - vegetation feedbacks in a fallow plot

    NASA Astrophysics Data System (ADS)

    Ursino, Nadia; Cassiani, Giorgio; Deiana, Rita; Vignoli, Giulio; Boaga, Jacopo

    2013-04-01

    Land fallowing is one possible response to shortage of water for irrigation. Leaving the soil unseeded implies a change of the soil functioning that has an impact on the water cycle. The development of a soil crust in the open spaces between the patterns of grass weed affects the soil properties and the field scale water balance. The objective of this study was to test the potential of integrated non invasive geophysics and ground-image analysis and to quantify the effect of the soil vegetation interaction on the water balance of a fallow land at the local and plot scale. We measured repeatedly in space and time local soil saturation and vegetation cover over two small plots located in southern Sardinia, Italy, during an infiltration experiment. One plot was left unseeded and the other was cultivated. The comparative analysis of the experimental data evidenced a positive feedback between weed growth and infiltration at the fallow plot. A simple bucket model captured the different soil moisture dynamics at the two plots during the infiltration experiment and was used to estimate the impact of the soil vegetation feedback on the yearly water balance at the site.

  18. DUS II SOIL GAS SAMPLING AND AIR INJECTION TEST RESULTS

    SciTech Connect

    Noonkester, J.; Jackson, D.; Jones, W.; Hyde, W.; Kohn, J.; Walker, R.

    2012-09-20

    Soil vapor extraction (SVE) and air injection well testing was performed at the Dynamic Underground Stripping (DUS) site located near the M-Area Settling Basin (referred to as DUS II in this report). The objective of this testing was to determine the effectiveness of continued operation of these systems. Steam injection ended on September 19, 2009 and since this time the extraction operations have utilized residual heat that is present in the subsurface. The well testing campaign began on June 5, 2012 and was completed on June 25, 2012. Thirty-two (32) SVE wells were purged for 24 hours or longer using the active soil vapor extraction (ASVE) system at the DUS II site. During each test five or more soil gas samples were collected from each well and analyzed for target volatile organic compounds (VOCs). The DUS II site is divided into four parcels (see Figure 1) and soil gas sample results show the majority of residual VOC contamination remains in Parcel 1 with lesser amounts in the other three parcels. Several VOCs, including tetrachloroethylene (PCE) and trichloroethylene (TCE), were detected. PCE was the major VOC with lesser amounts of TCE. Most soil gas concentrations of PCE ranged from 0 to 60 ppmv with one well (VEW-22A) as high as 200 ppmv. Air sparging (AS) generally involves the injection of air into the aquifer through either vertical or horizontal wells. AS is coupled with SVE systems when contaminant recovery is necessary. While traditional air sparging (AS) is not a primary component of the DUS process, following the cessation of steam injection, eight (8) of the sixty-three (63) steam injection wells were used to inject air. These wells were previously used for hydrous pyrolysis oxidation (HPO) as part of the DUS process. Air sparging is different from the HPO operations in that the air was injected at a higher rate (20 to 50 scfm) versus HPO (1 to 2 scfm). . At the DUS II site the air injection wells were tested to determine if air sparging affected

  19. Shallow Subsurface Soil Moisture Dynamics in the Root-Zone and Bulk Soil of Sparsely Vegetated Land Surfaces as Impacted by Near-Surface Atmospheric State

    NASA Astrophysics Data System (ADS)

    Trautz, A.; Illangasekare, T. H.; Tilton, N.

    2015-12-01

    Soil moisture is a fundamental state variable that provides the water necessary for plant growth and evapotranspiration. Soil moisture has been extensively studied in the context of bare surface soils and root zones. Less attention has focused on the effects of sparse vegetation distributions, such as those typical of agricultural cropland and other natural surface environments, on soil moisture dynamics. The current study explores root zone, bulk soil, and near-surface atmosphere interactions in terms of soil moisture under different distributions of sparse vegetation using multi-scale laboratory experimentation and numerical simulation. This research is driven by the need to advance our fundamental understanding of soil moisture dynamics in the context of improving water conservation and next generation heat and mass transfer numerical models. Experimentation is performed in a two-dimensional 7.3 m long intermediate scale soil tank interfaced with a climate-controlled wind tunnel, both of which are outfitted with current sensor technologies for measuring atmospheric and soil variables. The soil tank is packed so that a sparsely vegetated soil is surrounded by bulk bare soil; the two regions are separated by porous membranes to isolate the root zone from the bulk soil. Results show that in the absence of vegetation, evaporation rates vary along the soil tank in response to longitudinal changes in humidity; soil dries fastest upstream where evaporation rates are highest. In the presence of vegetation, soil moisture in the bulk soil closest to a vegetated region decreases more rapidly than the bulk soil farther away. Evapotranspiration rates in this region are also higher than the bulk soil region. This study is the first step towards the development of more generalized models that account for non-uniformly distributed vegetation and land surfaces exhibiting micro-topology.

  20. The influence of vegetation and soil characteristics on active-layer thickness of permafrost soils in boreal forest.

    PubMed

    Fisher, James P; Estop-Aragonés, Cristian; Thierry, Aaron; Charman, Dan J; Wolfe, Stephen A; Hartley, Iain P; Murton, Julian B; Williams, Mathew; Phoenix, Gareth K

    2016-09-01

    Carbon release from thawing permafrost soils could significantly exacerbate global warming as the active-layer deepens, exposing more carbon to decay. Plant community and soil properties provide a major control on this by influencing the maximum depth of thaw each summer (active-layer thickness; ALT), but a quantitative understanding of the relative importance of plant and soil characteristics, and their interactions in determine ALTs, is currently lacking. To address this, we undertook an extensive survey of multiple vegetation and edaphic characteristics and ALTs across multiple plots in four field sites within boreal forest in the discontinuous permafrost zone (NWT, Canada). Our sites included mature black spruce, burned black spruce and paper birch, allowing us to determine vegetation and edaphic drivers that emerge as the most important and broadly applicable across these key vegetation and disturbance gradients, as well as providing insight into site-specific differences. Across sites, the most important vegetation characteristics limiting thaw (shallower ALTs) were tree leaf area index (LAI), moss layer thickness and understory LAI in that order. Thicker soil organic layers also reduced ALTs, though were less influential than moss thickness. Surface moisture (0-6 cm) promoted increased ALTs, whereas deeper soil moisture (11-16 cm) acted to modify the impact of the vegetation, in particular increasing the importance of understory or tree canopy shading in reducing thaw. These direct and indirect effects of moisture indicate that future changes in precipitation and evapotranspiration may have large influences on ALTs. Our work also suggests that forest fires cause greater ALTs by simultaneously decreasing multiple ecosystem characteristics which otherwise protect permafrost. Given that vegetation and edaphic characteristics have such clear and large influences on ALTs, our data provide a key benchmark against which to evaluate process models used to predict

  1. An Intercomparison of Vegetation Products from Satellite-based Observations used for Soil Moisture Retrievals

    NASA Astrophysics Data System (ADS)

    Vreugdenhil, Mariette; de Jeu, Richard; Wagner, Wolfgang; Dorigo, Wouter; Hahn, Sebastian; Bloeschl, Guenter

    2013-04-01

    Vegetation and its water content affect active and passive microwave soil moisture retrievals and need to be taken into account in such retrieval methodologies. This study compares the vegetation parameterisation that is used in the TU-Wien soil moisture retrieval algorithm to other vegetation products, such as the Vegetation Optical Depth (VOD), Net Primary Production (NPP) and Leaf Area Index (LAI). When only considering the retrieval algorithm for active microwaves, which was developed by the TU-Wien, the effect of vegetation on the backscattering coefficient is described by the so-called slope [1]. The slope is the first derivative of the backscattering coefficient in relation to the incidence angle. Soil surface backscatter normally decreases quite rapidly with the incidence angle over bare or sparsely vegetated soils, whereas the contribution of dense vegetation is fairly uniform over a large range of incidence angles. Consequently, the slope becomes less steep with increasing vegetation. Because the slope is a derivate of noisy backscatter measurements, it is characterised by an even higher level of noise. Therefore, it is averaged over several years assuming that the state of the vegetation doesn't change inter-annually. The slope is compared to three dynamic vegetation products over Australia, the VOD, NPP and LAI. The VOD was retrieved from AMSR-E passive microwave data using the VUA-NASA retrieval algorithm and provides information on vegetation with a global coverage of approximately every two days [2]. LAI is defined as half the developed area of photosynthetically active elements of the vegetation per unit horizontal ground area. In this study LAI is used from the Geoland2 products derived from SPOT Vegetation*. The NPP is the net rate at which plants build up carbon through photosynthesis and is a model-based estimate from the BiosEquil model [3, 4]. Results show that VOD and slope correspond reasonably well over vegetated areas, whereas in arid

  2. [Effects of planting years of vegetable solar greenhouse on soil microbial flora and enzyme activities].

    PubMed

    Yang, Qin; Li, Liang

    2013-09-01

    Taking the vegetable solar greenhouses having been planted for 2, 4, 6, 11, 13, 16, and 19 years as test objects, and with the open vegetable field as the control, this paper studied the variations of soil microbial flora and enzyme activities. With the increasing years of planting, the numbers of soil bacteria, actinomycetes, and total microbes in vegetable solar greenhouses decreased after an initial increase, and reached the maximum in the greenhouse of 11 years planting, with a significant increment of 54.8%, 63.7%, and 55.4%, respectively, as compared to the control. The number of soil fungi in the vegetable solar greenhouses increased steadily with increasing planting years, being about 2.2 times higher in the greenhouse of 11 years planting. Among the microbial physiological groups, the numbers of aerobic cellulose-decomposer, aerobic azotobacter, nitrite bacteria, denitrifier, and sulphur reducer showed the same variation trend as the soil bacteria's, and those in the greenhouse of 11 years planting being 1.5, 1.6, 1.9, 1.4, and 1.1 times of the control, respectively. The number of ammonifiers increased after an initial decrease, reached the minimum in the greenhouse of 13 years planting, being only 56.0% of the control. The enzyme activities of soil urease, polyphenol oxidase, sucrase, protease, cellulase, and alkaline phosphatase increased firstly and then decreased with the increasing years of planting, but soil catalase activity was relatively stable. Correlation analysis showed that the numbers of soil bacteria, actinomycetes, and total microbes were significantly positively correlated with all test soil enzyme activities, while the number of soil fungi had significant negative correlation with the activity of soil catalase.

  3. PAHs in soils and estimated air-soil exchange in the Pearl River Delta, South China.

    PubMed

    Liu, Guoqing; Yu, Lili; Li, Jun; Liu, Xiang; Zhang, Gan

    2011-02-01

    In this study, 74 soil samples collected from the Pearl River Delta were analyzed for polycyclic aromatic hydrocarbons (PAHs). The PAH mixture in the soils is mainly of low molecular weight compounds, with naphthalene (21.4%) and phenanthrene (21.8%) being dominant. Soil PAH levels from the Pearl River Delta are relatively low (28-711 ng/g, averaged 192 ng/g) compared to those from urban soils in temperate regions. The mean concentration of ΣPAHs generally decrease with increasing distance from the city center, with ΣPAHs of paddy soils>crop soil>natural soil. PAHs in the air were measured during a year-round sampling campaign using semipermeable membrane devices, and the transfer of chemicals between the soil and air compartments were estimated. Soil-air fugacity quotient calculations showed a highly uncertain equilibrium position of PAHs, with net volatilization of naphthalene and fluorene, whereas net deposition of phenanthrene, fluoranthene, and pyrene, indicating a capacity for the air to supply the soil with more substances.

  4. [Relationships between typical vegetations, soil salinity, and groundwater depth in the Yellow River Delta of China].

    PubMed

    Ma, Yu-Lei; Wang, De; Liu, Jun-Min; Wen, Xiao-Hu; Gao, Meng; Shao, Hong-Bo

    2013-09-01

    Soil salinity and groundwater depth are the two important factors affecting the vegetation growth and distribution in the Yellow River Delta. Through field investigation and statistical analysis, this paper studied the relationships between the typical vegetations (Suaeda heteroptera-Tamarix chinensis, Robinia pseudoacacia, Phragmites australis, and cotton) , soil salinity, and groundwater depth in the Delta. In the study area, groundwater depth had significant effects on soil salinity, with the average influence coefficient being 0.327. When the groundwater depth was 0.5-1.5 m, soil salinization was most severe. The vegetation growth in the Delta was poorer, with the NDVI in 78% of the total area being less than 0.4. Groundwater depth and soil salinity had significant effects on the vegetation distribution. Soil salinity had significant effects on the NDVI of R. pseudoacacia, S. heteroptera-T. chinensis, P. australis, and cotton, while groundwater depth had significant effects on the NDVI of S. heteroptera - T. chinensis, but lesser effects on the NDVI of P. australis, cotton and R. pseudoacacia.

  5. Sulfamethazine Sorption to Soil: Vegetative Management, pH, and Dissolved Organic Matter Effects.

    PubMed

    Chu, Bei; Goyne, Keith W; Anderson, Stephen H; Lin, Chung-Ho; Lerch, Robert N

    2013-01-01

    Elucidating veterinary antibiotic interactions with soil is important for assessing and mitigating possible environmental hazards. The objectives of this study were to investigate the effects of vegetative management, soil properties, and >1000 Da dissolved organic matter (DOM) on sulfamethazine (SMZ) behavior in soil. Sorption experiments were performed over a range of SMZ concentrations (2.5-50 μmol L) using samples from three soils (Armstrong, Huntington, and Menfro), each planted to one of three vegetation treatments: agroforestry buffers strips (ABS), grass buffer strips (GBS), and row crops (RC). Our results show that SMZ sorption isotherms are well fitted by the Freundlich isotherm model (log = 0.44-0.93; Freundlich nonlinearity parameter = 0.59-0.79). Further investigation of solid-to-solution distribution coefficients () demonstrated that vegetative management significantly ( < 0.05) influences SMZ sorption (ABS > GBS > RC). Multiple linear regression analyses indicated that organic carbon (OC) content, pH, and initial SMZ concentration were important properties controlling SMZ sorption. Study of the two most contrasting soils in our sample set revealed that increasing solution pH (pH 6.0-7.5) reduced SMZ sorption to the Armstrong GBS soil, but little pH effect was observed for the Huntington GBS soil containing 50% kaolinite in the clay fraction. The presence of DOM (150 mg L OC) had little significant effect on the Freundlich nonlinearity parameter; however, DOM slightly reduced SMZ values overall. Our results support the use of vegetative buffers to mitigate veterinary antibiotic loss from agroecosystems, provide guidance for properly managing vegetative buffer strips to increase SMZ sorption, and enhance understanding of SMZ sorption to soil.

  6. Evolution of hydrological pathways in engineered hillslopes due to soil and vegetation development

    NASA Astrophysics Data System (ADS)

    Appels, Willemijn M.; Ireson, Andrew M.; McDonnell, Jeffrey J.; Barbour, S. Lee

    2015-04-01

    The structure and hydraulic properties of soils and bedrock within a hillslope combined with the timing and rates of water availability control the partitioning of precipitation into vertical and lateral flowpaths. In natural hillslope sites, heterogeneity in both soil texture and structure are the result of long-term landscape evolution processes and consequently can be assumed to be static relative to the timescale of rainfall-runoff processes. However; engineered hillslopes, constructed commonly as reclamation covers overlying mine waste, have been observed to undergo rapid changes in hydraulic properties over relatively short timescales (i.e. 3-5 years) as a result of weathering (e.g. freeze-thaw and wet-dry cycles) and vegetation growth (e.g. increasing rooting depth and density). Rainfall-runoff responses on such hillslopes would therefore not only be expected to reflect seasonal dynamics, but also the evolution of the system from a relatively homogeneous initial condition to a system with increasing heterogeneity of soil texture and structure. We present results of a combined field and modeling study of three prototype soil covers on a saline-sodic shale overburden dump at the Syncrude Canada Ltd. Mildred Lake mine, north of Fort McMurray, Canada. Since their construction in 1999, soil properties, hydrological response to atmospheric and vegetative demands, and vegetation properties have been extensively monitored. The three covers have undergone substantial evolution due to freeze-thaw processes and aggrading vegetation. In this work, we quantify hydrological processes in the reclamation covers, focusing on inter- and intra-annual patterns. To this purpose we analyzed the long-term hydrometric data with field sampling of the distribution of salts and the stable isotopes of water within soil water and subsurface flow in the base of the cover. We use a 2D Hydrus model to explore the co-evolution of soil and vegetation and quantify its effect on flow

  7. Monitoring soil-vegetation interactions using non-invasive geophysical techniques

    NASA Astrophysics Data System (ADS)

    Perri, M.; Cassiani, G.; Boaga, J.; Rossi, M.; Vignoli, G.; Deiana, R.; Ursino, N.; Putti, M.; Majone, B.; Bellin, A.; Blaschek, M.; Duttmann, R.; Meyer, S.; Ludwig, R.; Soddu, A.; Dietrich, P.; Werban, U.

    2012-12-01

    The understanding of soil-vegetation-atmosphere interactions is of utmost importance in the solution of a number of hydrological questions and practical issues, including flood control, agricultural best practice, slope stability and impacts of climatic changes. Geophysical time-lapse monitoring can greatly contribute to the understanding of these interactions particularly for its capability to map in space and time the effects of vegetation on soil moisture content. In this work we present the results of two case studies showing the potential of hydro-geophysics in this context. The first example refers to the long term monitoring of the soil static and dynamic characteristics in an experimental site located in Sardinia (Italy). The main objective of this study is to understand the effects of soil - water - plants interactions on soil water balance. A combination of time-lapse electromagnetic induction (EMI) monitoring over wide areas and localized irrigation tests monitored by electrical resistivity tomography (ERT) and TDR soil moisture measurements is here used, in order to achieve quantitative field-scale estimates of moisture content from topsoil layer. Natural gamma-ray emission mapping, texture analysis and laboratory calibration of an electrical constitutive relationship on soil samples complete the dataset. We therefore observed that the growth of vegetation, with the associated below ground allocation of biomass, has a significant impact on the soil moisture dynamics. In particular vegetation extracts a large amount of water from the soil in the hot season, but it also reduces evaporation by shadowing the soil surface. In addition, vegetation enhances the soil wetting process as the root system facilitates water infiltration, thus creating a positive feedback system. The second example regards the time-lapse monitoring of soil moisture content in an apple orchard located in the Alpine region of Northern Italy (Trento). A three-dimensional cross-hole ERT

  8. Estimation of effective hydrologic properties of soils from observations of vegetation density

    NASA Technical Reports Server (NTRS)

    Tellers, T. E.; Eagleson, P. S.

    1980-01-01

    A one-dimensional model of the annual water balance is reviewed. Improvements are made in the method of calculating the bare soil component of evaporation, and in the way surface retention is handled. A natural selection hypothesis, which specifies the equilibrium vegetation density for a given, water limited, climate soil system, is verified through comparisons with observed data. Comparison of CDF's of annual basin yield derived using these soil properties with observed CDF's provides verification of the soil-selection procedure. This method of parameterization of the land surface is useful with global circulation models, enabling them to account for both the nonlinearity in the relationship between soil moisture flux and soil moisture concentration, and the variability of soil properties from place to place over the Earth's surface.

  9. Utilization of vegetation indices to improve microwave soil moisture estimates over agricultural lands

    NASA Technical Reports Server (NTRS)

    Theis, S. W.; Blanchard, B. J.; Newton, R. W.

    1984-01-01

    A technique is presented by means of which visible/near-IR data are used to develop corrections in remotely sensed microwave soil moisture signals, in order to account for vegetation effects. Visible/IR data collected with the NASA NS001 Thematic Mapper Simulator were used to calculate the Perpendicular Vegetation Index (PVI), which was then related to the change of sensitivity of the microwave measurement to surface soil moisture. Effective estimation of soil moisture in the presence of vegetation can be made with L-band microwave radiometers and visible/IR sensors when the PVI is lower than 4.3. This technique offers a means for the estimation of moisture from a space platform over many agricultural areas, without expensive ground data collection.

  10. The effect of bullet removal and vegetation on mobility of Pb in shooting range soils.

    PubMed

    Fayiga, Abioye O; Saha, Uttam

    2016-10-01

    Lead (Pb) contamination at shooting ranges is a public health concern because Pb is a toxic metal. An experiment was conducted to determine the effect of two best management practices; bullet removal and vegetation, on bioavailability and leachability of Pb in three shooting range (SR) soils. St. Augustine grass was grown in sieved (2 mm) and un-sieved SR soils for 8 weeks after which leachates, soil and plant samples were analyzed. Bullet removal reduced total soil Pb, increased Mehlich-3 Pb in unvegetated soils and increased dissolved organic carbon (DOC) in all soils. Bullet removal increased leaching in two SR soils while grasses reduced leaching but increased water soluble Pb in two SR soils. The roots of the grasses were able to accumulate more Pb in the root (1893-5021 mg kg(-1)) than the aboveground biomass (252-880 mg kg(-1)) due to mobilization of Pb in the rhizosphere. Grasses had a higher plant biomass in unsieved soils suggesting tolerance to the presence of bullets in the unsieved soils. Results suggest that bullet removal probably increased microbial activity and Pb bioavailability in the soil. The leaching and bioavailability of Pb in shooting range soils depends on biological activities and chemical processes in the soil.

  11. Does vegetation type matter? Plant-soil interactions change urban rain garden hydrology

    NASA Astrophysics Data System (ADS)

    Johnston, M. R.; Balster, N. J.

    2009-12-01

    Residential infiltration basins or rain gardens are being installed at an ever-increasing rate across the urban landscape, yet their impact on the urban hydrologic cycle remains largely untested. Specifically, because rain garden design varies considerably, we know little about how plant-soil dynamics control their hydrologic function. In a controlled field experiment with closed-system rain gardens, we tested the hydrologic response of three vegetation treatments common in rain garden design (shrubs, wet-mesic prairie, turfgrass). We used a complete, randomized block design in which each vegetative treatment was replicated three times. Each rain garden represented 17% of a contributing roof area where stormwater was collected and then applied following precipitation events. We continuously monitored stormwater input, soil water content, and soil exfiltration to assess differences in the hydrologic function of each rain garden. Overall, vegetation type significantly changed the magnitude and timing of the hydrologic response. During the months of June and July, 2009, the rain gardens planted with shrubs, prairie, and turfgrass all reduced the volume of soil exfiltration by 50%, 30%, and 17%, respectively, relative to the non-vegetated controls. Similarly, depending on storm magnitude and antecedent soil moisture, vegetation type significantly decreased the mean peak flow rate of exfiltration (p < 0.001), as well as the duration of the exfiltration response (p < 0.0001). The flashiest hydrologic responses (i.e. shortest lag time, highest peak flow rate) were observed in the turfgrass gardens. We explain these vegetative-mediated responses in hydrology relative to differences in infiltration, aboveground dry mass, root dynamics, and transpirative loss. Our data suggest that changing the vegetation type of urban rain gardens yields marked differences in the hydrologic budget via shifts in ecohydrological processes.

  12. Mapping the spectral variability in photosynthetic and non-photosynthetic vegetation, soils, and shade using AVIRIS

    NASA Technical Reports Server (NTRS)

    Roberts, Dar A.; Smith, Milton O.; Sabol, Donald E.; Adams, John B.; Ustin, Susan L.

    1992-01-01

    The primary objective of this research was to map as many spectrally distinct types of green vegetation (GV), non-photosynthetic vegetation (NPV), shade, and soil (endmembers) in an Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) scene as is warranted by the spectral variability of the data. Once determined, a secondary objective was to interpret these endmembers and their abundances spatially and spectrally in an ecological context.

  13. Soil temperature prediction from air temperature for alluvial soils in lower Indo-Gangetic plain

    NASA Astrophysics Data System (ADS)

    Barman, D.; Kundu, D. K.; Pal, Soumen; Pal, Susanto; Chakraborty, A. K.; Jha, A. K.; Mazumdar, S. P.; Saha, R.; Bhattacharyya, P.

    2017-01-01

    Soil temperature is an important factor in biogeochemical processes. On-site monitoring of soil temperature is limited in spatiotemporal scale as compared to air temperature data inventories due to various management difficulties. Therefore, empirical models were developed by taking 30-year long-term (1985-2014) air and soil temperature data for prediction of soil temperatures at three depths (5, 15, 30 cm) in morning (0636 Indian standard time) and afternoon (1336 Indian standard time) for alluvial soils in lower Indo-Gangetic plain. At 5 cm depth, power and exponential regression models were best fitted for daily data in morning and afternoon, respectively, but it was reverse at 15 cm. However, at 30 cm, exponential models were best fitted for both the times. Regression analysis revealed that in morning for all three depths and in afternoon for 30 cm depth, soil temperatures (daily, weekly, and monthly) could be predicted more efficiently with the help of corresponding mean air temperature than that of maximum and minimum. However, in afternoon, prediction of soil temperature at 5 and 15 cm depths were more precised for all the time intervals when maximum air temperature was used, except for weekly soil temperature at 15 cm, where the use of mean air temperature gave better prediction.

  14. Plant functional diversity enhances associations of soil fungal diversity with vegetation and soil in the restoration of semiarid sandy grassland.

    PubMed

    Zuo, Xiaoan; Wang, Shaokun; Lv, Peng; Zhou, Xin; Zhao, Xueyong; Zhang, Tonghui; Zhang, Jing

    2016-01-01

    The trait-based approach shows that plant functional diversity strongly affects ecosystem properties. However, few empirical studies show the relationship between soil fungal diversity and plant functional diversity in natural ecosystems. We investigated soil fungal diversity along a restoration gradient of sandy grassland (mobile dune, semifixed dune, fixed dune, and grassland) in Horqin Sand Land, northern China, using the denaturing gradient gel electrophoresis of 18S rRNA and gene sequencing. We also examined associations of soil fungal diversity with plant functional diversity reflected by the dominant species' traits in community (community-weighted mean, CWM) and the dispersion of functional trait values (FD is). We further used the structure equation model (SEM) to evaluate how plant richness, biomass, functional diversity, and soil properties affect soil fungal diversity in sandy grassland restoration. Soil fungal richness in mobile dune and semifixed dune was markedly lower than those of fixed dune and grassland (P < 0.05). Soil fungal richness was positively associated with plant richness, biomass, CWM plant height, and soil gradient aggregated from the principal component analysis, but SEM results showed that plant richness and CWM plant height determined by soil properties were the main factors exerting direct effects. Soil gradient increased fungal richness through indirect effect on vegetation rather than direct effect. The negative indirect effect of FDis on soil fungal richness was through its effect on plant biomass. Our final SEM model based on plant functional diversity explained nearly 70% variances of soil fungal richness. Strong association of soil fungal richness with the dominant species in the community supported the mass ratio hypothesis. Our results clearly highlight the role of plant functional diversity in enhancing associations of soil fungal diversity with community structure and soil properties in sandy grassland ecosystems.

  15. Vegetation Types Alter Soil Respiration and Its Temperature Sensitivity at the Field Scale in an Estuary Wetland

    PubMed Central

    Han, Guangxuan; Xing, Qinghui; Luo, Yiqi; Rafique, Rashad; Yu, Junbao; Mikle, Nate

    2014-01-01

    Vegetation type plays an important role in regulating the temporal and spatial variation of soil respiration. Therefore, vegetation patchiness may cause high uncertainties in the estimates of soil respiration for scaling field measurements to ecosystem level. Few studies provide insights regarding the influence of vegetation types on soil respiration and its temperature sensitivity in an estuary wetland. In order to enhance the understanding of this issue, we focused on the growing season and investigated how the soil respiration and its temperature sensitivity are affected by the different vegetation (Phragmites australis, Suaeda salsa and bare soil) in the Yellow River Estuary. During the growing season, there were significant linear relationships between soil respiration rates and shoot and root biomass, respectively. On the diurnal timescale, daytime soil respiration was more dependent on net photosynthesis. A positive correlation between soil respiration and net photosynthesis at the Phragmites australis site was found. There were exponential correlations between soil respiration and soil temperature, and the fitted Q10 values varied among different vegetation types (1.81, 2.15 and 3.43 for Phragmites australis, Suaeda salsa and bare soil sites, respectively). During the growing season, the mean soil respiration was consistently higher at the Phragmites australis site (1.11 µmol CO2 m−2 s−1), followed by the Suaeda salsa site (0.77 µmol CO2 m−2 s−1) and the bare soil site (0.41 µmol CO2 m−2 s−1). The mean monthly soil respiration was positively correlated with shoot and root biomass, total C, and total N among the three vegetation patches. Our results suggest that vegetation patchiness at a field scale might have a large impact on ecosystem-scale soil respiration. Therefore, it is necessary to consider the differences in vegetation types when using models to evaluate soil respiration in an estuary wetland. PMID:24608636

  16. Vegetation types alter soil respiration and its temperature sensitivity at the field scale in an estuary wetland.

    PubMed

    Han, Guangxuan; Xing, Qinghui; Luo, Yiqi; Rafique, Rashad; Yu, Junbao; Mikle, Nate

    2014-01-01

    Vegetation type plays an important role in regulating the temporal and spatial variation of soil respiration. Therefore, vegetation patchiness may cause high uncertainties in the estimates of soil respiration for scaling field measurements to ecosystem level. Few studies provide insights regarding the influence of vegetation types on soil respiration and its temperature sensitivity in an estuary wetland. In order to enhance the understanding of this issue, we focused on the growing season and investigated how the soil respiration and its temperature sensitivity are affected by the different vegetation (Phragmites australis, Suaeda salsa and bare soil) in the Yellow River Estuary. During the growing season, there were significant linear relationships between soil respiration rates and shoot and root biomass, respectively. On the diurnal timescale, daytime soil respiration was more dependent on net photosynthesis. A positive correlation between soil respiration and net photosynthesis at the Phragmites australis site was found. There were exponential correlations between soil respiration and soil temperature, and the fitted Q10 values varied among different vegetation types (1.81, 2.15 and 3.43 for Phragmites australis, Suaeda salsa and bare soil sites, respectively). During the growing season, the mean soil respiration was consistently higher at the Phragmites australis site (1.11 µmol CO2 m(-2) s(-1)), followed by the Suaeda salsa site (0.77 µmol CO2 m(-2) s(-1)) and the bare soil site (0.41 µmol CO2 m(-2) s(-1)). The mean monthly soil respiration was positively correlated with shoot and root biomass, total C, and total N among the three vegetation patches. Our results suggest that vegetation patchiness at a field scale might have a large impact on ecosystem-scale soil respiration. Therefore, it is necessary to consider the differences in vegetation types when using models to evaluate soil respiration in an estuary wetland.

  17. Relations between soil moisture and satellite vegetation indices in the U.S. Corn Belt

    USGS Publications Warehouse

    Adegoke, Jimmy O.; Carleton, A.M.

    2002-01-01

    Satellite-derived vegetation indices extracted over locations representative of midwestern U.S. cropland and forest for the period 1990–94 are analyzed to determine the sensitivity of the indices to neutron probe soil moisture measurements of the Illinois Climate Network (ICN). The deseasoned (i.e., departures from multiyear mean annual cycle) soil moisture measurements are shown to be weakly correlated with the deseasoned full resolution (1 km × 1 km) normalized difference vegetation index (NDVI) and fractional vegetation cover (FVC) data over both land cover types. The association, measured by the Pearson-moment-correlation coefficient, is stronger over forest than over cropland during the growing season (April–September). The correlations improve successively when the NDVI and FVC pixel data are aggregated to 3 km × 3 km, 5 km × 5 km, and 7 km × 7 km areas. The improved correlations are partly explained by the reduction in satellite navigation errors as spatial aggregation occurs, as well as the apparent scale dependence of the NDVI–soil moisture association. Similarly, stronger relations are obtained with soil moisture data that are lagged by up to 8 weeks with respect to the vegetation indices, implying that soil moisture may be a useful predictor of warm season satellite-derived vegetation conditions. This study suggests that a “long-term” memory of several weeks is present in the near-surface hydrological characteristics, especially soil water content, of the Midwest Corn Belt. The memory is integrated into the satellite vegetation indices and may be useful for predicting crop yield estimates and surface temperature anomalies.

  18. Assessment of Fluoride Concentration of Soil and Vegetables in Vicinity of Zinc Smelter, Debari, Udaipur, Rajasthan

    PubMed Central

    Bhat, Nagesh; Asawa, Kailash; Tak, Mridula; Shinde, Kushal; Singh, Anukriti; Gandhi, Neha; Gupta, Vivek Vardhan

    2015-01-01

    Background As of late, natural contamination has stimulated as a reaction of mechanical and other human exercises. In India, with the expanding industrialization, numerous unsafe substances are utilized or are discharged amid generation as cleans, exhaust, vapours and gasses. These substances at last are blended in the earth and causes health hazards. Objective To determine concentration of fluoride in soils and vegetables grown in the vicinity of Zinc Smelter, Debari, Udaipur, Rajasthan. Materials and Methods Samples of vegetables and soil were collected from areas situated at 0, 1, 2, 5, and 10 km distance from the zinc smelter, Debari. Three samples of vegetables (i.e. Cabbage, Onion and Tomato) and 3 samples of soil {one sample from the upper layer of soil (i.e. 0 to 20 cm) and one from the deep layer (i.e. 20 – 40 cm)} at each distance were collected. The soil and vegetable samples were sealed in clean polythene bags and transported to the laboratory for analysis. One sample each of water and fertilizer from each distance were also collected. Results The mean fluoride concentration in the vegetables grown varied between 0.36 ± 0.69 to 0.71 ± 0.90 ppm. The fluoride concentration in fertilizer and water sample from various distances was found to be in the range of 1.4 – 1.5 ppm and 1.8 – 1.9 ppm respectively. Conclusion The fluoride content of soil and vegetables was found to be higher in places near to the zinc smelter. PMID:26557620

  19. Agricultural use of soil, consequences in soil organic matter and hydraulic conductivity compared with natural vegetation in central Spain

    NASA Astrophysics Data System (ADS)

    Vega, Verónica; Carral, Pilar; Alvarez, Ana Maria; Marques, Maria Jose

    2014-05-01

    When ecosystems are under pressure due to high temperatures and water scarcity, the use of land for agriculture can be a handicap for soil and water conservation. The interactions between plants and soils are site-specific. This study provides information about the influence of the preence vs. The absence of vegetation on soil in a semi-arid area of the sout-east of Madrid (Spain, in the Tagus River basin. In this area soil materials are developed over a calcareous-evaporitic lithology. Soils can be classified as Calcisols, having horizons of accumulation with powdered limestone and irregular nodules of calcium carbonate. They can be defined as Haplic Cambisols and Leptic Calcisols (WRB 2006-FAO). The area is mainly used for rainfed agriculture, olive groves, vineyards and cereals. There are some patches of bushes (Quercus sp.) and grasses (Stipa tenacissima L.) although only found on the top of the hills. This study analyses the differences found in soils having three different covers: Quercus coccifera, Stipa tenacissima and lack of vegetation. This last condition was found in the areas between cultivated olive trees. Soil organic matter, porosity and hydraulic conductivity are key properties of soil to understand its ability to adapt to climate or land use changes. In order to measure the influence of different soil covers, four replicates of soil were sampled in each condition at two soil depth, (0-10 cm and 10-20 cm). Hydraulic conductivity was measured in each soil condition and replicate using a Mini-disk® infiltrometer. There were no differences between the two depths sampled. Similarly, there were no changes in electric conductivity (average 0.1±0.03 dS m-1); pH (8.7±0.2) or calcium carbonate content (43±20 %). Nevertheless, significant differences (p>0.001) were found in soil organic matter. The maximum was found in soils under Quercus (4.7±0.5 %), followed by Stipa (2.2±1.1 %). The soil without vegetation in the areas between olive trees had only 0

  20. Vegetation-induced spatial variability of soil redox properties in wetlands

    NASA Astrophysics Data System (ADS)

    Szalai, Zoltán; Jakab, Gergely; Kiss, Klaudia; Ringer, Marianna; Balázs, Réka; Zacháry, Dóra; Horváth Szabó, Kata; Perényi, Katalin

    2016-04-01

    Vegetation induced land patches may result spatial pattern of on soil Eh and pH. These spatial pattern are mainly emerged by differences of aeration and exudation of assimilates. Present paper focuses on vertical extent and temporal dynamics of these patterns in wetlands. Two study sites were selected: 1. a plain wetland on calcareous sandy parent material (Ceglédbercel, Danube-Tisza Interfluve, Hungary); 2. headwater wetland with calcareous loamy parent material (Bátaapáti, Hungary). Two vegetation patches were studied in site 1: sedgy (dominated by Carex riparia) and reedy (dominated by Phragmites australis). Three patches were studied in site2: sedgy1 (dominated by C vulpina), sedgy 2 (C. riparia); nettle-horsetail (Urtica dioica and Equisetum arvense). Boundaries between patches were studied separately. Soil redox, pH and temperature studied by automated remote controlled instruments. Three digital sensors (Ponsell) were installed in each locations: 20cm and 40cm sensors represent the solum and 100 cm sensor monitors the subsoil). Groundwater wells were installed near to triplets for soil water sampling. Soil Eh, pH and temperature values were recorded in each 10 minutes. Soil water sampling for iron and DOC were carried out during saturated periods. Spatial pattern of soil Eh is clearly caused by vegetation. We measured significant differences between Eh values of the studied patches in the solum. We did not find this kinds horizontal differences in the subsoil. Boundaries of the patches usually had more reductive soil environment than the core areas. We have found temporal dynamics of the spatial redox pattern. Differences were not so well expressed during wintertime. These spatial patterns had influence on the DOC and iron content of porewater, as well. Highest temporal dynamics of soil redox properties and porewater iron could be found in the boundaries. These observations refer to importance patchiness of vegetation on soil chemical properties in

  1. Understory vegetation leads to changes in soil acidity and in microbial communities 27 years after reforestation.

    PubMed

    Fu, Xiaoli; Yang, Fengting; Wang, Jianlei; Di, Yuebao; Dai, Xiaoqin; Zhang, Xinyu; Wang, Huimin

    2015-01-01

    Experiments with potted plants and removed understories have indicated that understory vegetation often affects the chemical and microbial properties of soil. In this study, we examined the mechanism and extent of the influence of understory vegetation on the chemical and microbial properties of soil in plantation forests. The relationships between the vegetational structure (diversity for different functional layers, aboveground biomass of understory vegetation, and species number) and soil properties (pH, microbial community structure, and levels of soil organic carbon, total nitrogen, and inorganic nitrogen) were analyzed across six reforestation types (three pure needleleaf forests, a needle-broadleaf mixed forest, a broadleaf forest, and a shrubland). Twenty-seven years after reforestation, soil pH significantly decreased by an average of 0.95 across reforestation types. Soil pH was positively correlated with the aboveground biomass of the understory. The levels of total, bacterial, and fungal phospholipid fatty acids, and the fungal:bacterial ratios were similar in the shrubland and the broadleaf forest. Both the aboveground biomass of the understory and the diversity of the tree layer positively influenced the fungal:bacterial ratio. Improving the aboveground biomass of the understory could alleviate soil acidification. An increase in the aboveground biomass of the understory, rather than in understory diversity, enhanced the functional traits of the soil microbial communities. The replacement of pure plantations with mixed-species stands, as well as the enhancement of understory recruitment, can improve the ecological functions of a plantation, as measured by the alleviation of soil acidification and increased fungal dominance.

  2. [Sizes of soil macropores and related main affecting factors on a vegetated basalt slope].

    PubMed

    Guan, Qi; Xu, Ze-Min; Tian, Lin

    2013-10-01

    The landslide on vegetated slopes caused by extreme weather has being increased steadily, and the preferential flow in soil macropores plays an important role in the landslide. By using water breakthrough curve and Poiseuille equation, this paper estimated the radius range, amount, and average volume of soil macropores on a vegetated basalt slope of Maka Mountain, Southwest China, and analyzed the distribution of the soil macropores and the main affecting factors. In the study area, the radius of soil macropores ranged from 0.3 to 1.8 mm, mainly between 0.5 and 1.2 mm. The large-radius macropores (1.4-1.8 mm) were lesser, while the small-radius macropores (< 1.4 mm) were more. With the development of soil profile, soil macropores were more in upper layers and lesser in deeper layers. The average volume of the macropores contributed 84.7% to the variance of steady effluent rate. Among the factors affecting the average volume of the large macropores, vegetations root mass had a linear relationship, with the correlation coefficient being 0.70, and soil organic matter content also had a linear relationship, with the correlation coefficient being 0.64.

  3. The Soil Biota Composition along a Progressive Succession of Secondary Vegetation in a Karst Area

    PubMed Central

    He, Xunyang; Liu, Lu; Wang, Kelin

    2014-01-01

    Karst ecosystems are fragile and are in many regions degraded by anthropogenic activities. Current management of degraded karst areas focuses on aboveground vegetation succession or recovery and aims at establishing a forest ecosystem. Whether progressive succession of vegetation in karst areas is accompanied by establishment of soil biota is poorly understood. In the present study, soil microbial and nematode communities, as well as soil physico-chemical properties were studied along a progressive succession of secondary vegetation (from grassland to shrubland to forest) in a karst area in southwest China. Microbial biomass, nematode density, ratio of fungal to bacterial biomass, nematode structure index, and nematode enrichment index decreased with the secondary succession in the plant community. Overall, the results indicated a pattern of declines in soil biota abundance and food web complexity that was associated with a decrease in soil pH and a decrease in soil organic carbon content with the progressive secondary succession of the plant community. Our findings suggest that soil biota amendment is necessary during karst ecosystem restoration and establishment and management of grasslands may be feasible in karst areas. PMID:25379741

  4. The soil biota composition along a progressive succession of secondary vegetation in a karst area.

    PubMed

    Zhao, Jie; Li, Shengping; He, Xunyang; Liu, Lu; Wang, Kelin

    2014-01-01

    Karst ecosystems are fragile and are in many regions degraded by anthropogenic activities. Current management of degraded karst areas focuses on aboveground vegetation succession or recovery and aims at establishing a forest ecosystem. Whether progressive succession of vegetation in karst areas is accompanied by establishment of soil biota is poorly understood. In the present study, soil microbial and nematode communities, as well as soil physico-chemical properties were studied along a progressive succession of secondary vegetation (from grassland to shrubland to forest) in a karst area in southwest China. Microbial biomass, nematode density, ratio of fungal to bacterial biomass, nematode structure index, and nematode enrichment index decreased with the secondary succession in the plant community. Overall, the results indicated a pattern of declines in soil biota abundance and food web complexity that was associated with a decrease in soil pH and a decrease in soil organic carbon content with the progressive secondary succession of the plant community. Our findings suggest that soil biota amendment is necessary during karst ecosystem restoration and establishment and management of grasslands may be feasible in karst areas.

  5. A Broad Approach to Abrupt Boundaries: Looking Beyond the Boundary at Soil Attributes within and Across Tropical Vegetation Types

    PubMed Central

    Warman, Laura; Bradford, Matt G.; Moles, Angela T.

    2013-01-01

    Most research on boundaries between vegetation types emphasizes the contrasts and similarities between conditions on either side of a boundary, but does not compare boundary to non-boundary vegetation. That is, most previous studies lack suitable controls, and may therefore overlook underlying aspects of landscape variability at a regional scale and underestimate the effects that the vegetation itself has on the soil. We compared 25 soil chemistry variables in rainforest, sclerophyll vegetation and across rainforest-sclerophyll boundaries in north-eastern Queensland, Australia. Like previous studies, we did find some contrasts in soil chemistry across vegetation boundaries. However we did not find greater variation in chemical parameters across boundary transects than in transects set in either rainforest or woodland. We also found that soil on both sides of the boundary is more similar to “rainforest soil” than to “woodland soil”. Transects in wet sclerophyll forests with increasing degrees of rainforest invasion showed that as rainforest invades wet sclerophyll forest, the soil beneath wet sclerophyll forest becomes increasingly similar to rainforest soil. Our results have implications for understanding regional vegetation dynamics. Considering soil-vegetation feedbacks and the differences between soil at boundaries and in non-boundary sites may hold clues to some of the processes that occur across and between vegetation types in a wide range of ecosystems. Finally, we suggest that including appropriate controls should become standard practice for studies of vegetation boundaries and edge effects worldwide. PMID:23593312

  6. Field determination and QSPR prediction of equilibrium-status soil/vegetation partition coefficient of PCDD/Fs.

    PubMed

    Li, Li; Wang, Qiang; Qiu, Xinghua; Dong, Yian; Jia, Shenglan; Hu, Jianxin

    2014-07-15

    Characterizing pseudo equilibrium-status soil/vegetation partition coefficient KSV, the quotient of respective concentrations in soil and vegetation of a certain substance at remote background areas, is essential in ecological risk assessment, however few previous attempts have been made for field determination and developing validated and reproducible structure-based estimates. In this study, KSV was calculated based on measurements of seventeen 2,3,7,8-substituted PCDD/F congeners in soil and moss (Dicranum angustum), and rouzi grass (Thylacospermum caespitosum) of two background sites, Ny-Ålesund of the Arctic and Zhangmu-Nyalam region of the Tibet Plateau, respectively. By both fugacity modeling and stepwise regression of field data, the air-water partition coefficient (KAW) and aqueous solubility (SW) were identified as the influential physicochemical properties. Furthermore, validated quantitative structure-property relationship (QSPR) model was developed to extrapolate the KSV prediction to all 210 PCDD/F congeners. Molecular polarizability, molecular size and molecular energy demonstrated leading effects on KSV.

  7. Effect of vegetation on the presence and genetic diversity of Bacillus thuringiensis in soil.

    PubMed

    Ricieto, Ana Paula Scaramal; Fazion, Fernanda Aparecida Pires; Carvalho Filho, Celso Duarte; Vilas-Boas, Laurival Antonio; Vilas-Bôas, Gislayne Trindade

    2013-01-01

    Bacillus thuringiensis isolates were obtained from soil samples collected at different sites located in the same region but with different vegetation. The sites showed different frequencies of B. thuringiensis, depending on the type of vegetation. Strains of B. thuringiensis were found to be less common in samples of riparian forest soil than in soil of other types of vegetation. The rate of occurrence of B. thuringiensis in the samples also varied according to the vegetation. These results show that whenever this bacterium was found, it showed a high rate of occurrence, indicating that this species could be better adapted to using soil as a reservoir than other Bacillus species. The presence of cry genes was analyzed by polymerase chain reaction, and genes that exhibited activity against Diptera species were the most commonly found. The isolates obtained were characterized by random amplified polymorphic DNA, and 50% were clustered into clonal groups. These results demonstrated the possible occurrence of a high number of genetically similar strains when samples are collected from the same region, even if they are from locations with different vegetation.

  8. Arsenic and Lead Uptake by Vegetable Crops Grown on Historically Contaminated Orchard Soils

    PubMed Central

    2015-01-01

    Transfer of Pb and As into vegetables grown in orchard soils historically contaminated by Pb arsenate pesticides was measured in the greenhouse. Lettuce, carrots, green beans and tomatoes were grown on soils containing a range of total Pb (16.5–915 mg/kg) and As (6.9–211 mg/kg) concentrations. The vegetables were acid-digested and analyzed for total Pb and As using ICP-mass spectrometry. Vegetable contamination was dependent on soil total Pb and As content, pH, and vegetable species. Arsenic concentrations were highest in lettuce and green beans, lower in carrots, and much lower in tomato fruit. Transfer of Pb into lettuce and beans was generally lower than that of As, and Pb and As were strongly excluded from tomato fruit. Soil metal concentrations as high as 400 mg/kg Pb and 100 mg/kg As produced vegetables with concentrations of Pb and As below the limits of international health standards. PMID:26949393

  9. Soils under conservation agriculture with vegetables in Siem Reap, Cambodia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Smallholder vegetable farmers in Siem Reap, Cambodia experienced declining crop productivity. It could be a result of a mixture of factors such as nutrient and pest problems and extreme weather events such as droughts and/or heavy rains. The no-till, continuous mulch and diverse species principles o...

  10. Vegetation and climate controls on potential CO2, DOC and DON production in northern latitude soils

    USGS Publications Warehouse

    Neff, J.C.; Hooper, D.U.

    2002-01-01

    Climatic change may influence decomposition dynamics in arctic and boreal ecosystems, affecting both atmospheric CO2 levels, and the flux of dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) to aquatic systems. In this study, we investigated landscape-scale controls on potential production of these compounds using a one-year laboratory incubation at two temperatures (10?? and 30??C). We measured the release of CO2, DOC and DON from tundra soils collected from a variety of vegetation types and climatic regimes: tussock tundra at four sites along a latitudinal gradient from the interior to the north slope of Alaska, and soils from additional vegetation types at two of those sites (upland spruce at Fairbanks, and wet sedge and shrub tundra at Toolik Lake in northern Alaska). Vegetation type strongly influenced carbon fluxes. The highest CO2 and DOC release at the high incubation temperature occurred in the soils of shrub tundra communities. Tussock tundra soils exhibited the next highest DOC fluxes followed by spruce and wet sedge tundra soils, respectively. Of the fluxes, CO2 showed the greatest sensitivity to incubation temperatures and vegetation type, followed by DOC. DON fluxes were less variable. Total CO2 and total DOC release were positively correlated, with DOC fluxes approximately 10% of total CO2 fluxes. The ratio of CO2 production to DOC release varied significantly across vegetation types with Tussock soils producing an average of four times as much CO2 per unit DOC released compared to Spruce soils from the Fairbanks site. Sites in this study released 80-370 mg CO2-C g soil C-1 and 5-46 mg DOC g soil C-1 at high temperatures. The magnitude of these fluxes indicates that arctic carbon pools contain a large proportion of labile carbon that could be easily decomposed given optimal conditions. The size of this labile pool ranged between 9 and 41% of soil carbon on a g soil C basis, with most variation related to vegetation type rather than

  11. Effects of vegetation on radon transport processes in soil

    SciTech Connect

    Borak, T.B.

    1991-01-01

    This research was conducted to measure radon concentrations. Radon concentrations in soil gas were measured on a weekly schedule. Samples were extracted through the tubes used for measuring pressure differentials at depths of 30, 100, 180 cm. The average soil moisture content was measured with the neutron gauge. Other soil parameters such as soil temperature and meteorological data were analyzed in order to determine their influence on soil radon concentrations. For indoor radon concentrations, 15 minute measurements were used to obtain a monthly average for one structure from January 1989--August 1990. Also measured were wind speed and pressure differential correlations with radon concentration. The salient features of the data obtained thus far are as follows: radon gas concentrations in the silty clay surrounding the structures increased with depth; monthly averaged radon concentrations in the underground structures do not exhibit obvious seasonal variations; indoor radon concentrations are not correlation with pressure differences between the structure and surrounding soil; for these structures the radon entry rate has two components; one that is constant and the other that changes with time; and the wind speeds that increase the radon entry rate, also increase the ventilation rate. 11 figs.

  12. Influences of biochar addition on vegetable soil nitrogen balance and pH buffering capacity

    NASA Astrophysics Data System (ADS)

    Yu, Y.; Odindo, AO; Xue, L.; Yang, L.

    2016-08-01

    Leaching is a major path for chemical nitrogen fertilizer loss from in vegetable soil, which would destroy soil pH buffering capacity soil and result in acidification. It has been a common phenomenon in Tai Lake Region, China. However, few study focused on the change soil pH buffering capacity, especially the effect of soil amendment on pH buffering capacity. In this study, a pot experiment was conducted to research the effects of biochar addition to a vegetable soil on nitrogen leaching and pH buffering capacity with pakchoi (B.chinensis L.) growth as the experimental crop. The results showed that biochar could significantly increase the pakchoi nitrogen utilization efficiency, decrease 48%-65% nitrogen loss from leaching under the urea continuous applied condition. Biochar also could effectively maintain the content of soil organic matter and base cations. Therefore, it rose up soil pH buffering capacity by 9.4%-36.8% and significantly slowed down acidification rate. It was suggested that 1%-2% addition ratio was recommended from this study when used as similar soil condition.

  13. Influence of PAH speciation in soils on vegetative uptake of PAHs using successive extraction.

    PubMed

    Zhang, Juan; Fan, Shu-Kai

    2016-12-15

    Polycyclic aromatic hydrocarbon (PAH) speciation in soils and the relationship between PAH speciation in soils and the accumulation of PAHs in vegetables have rarely been reported. In this study, the organic solvent extractable PAHs in soils, PAHs that bind to endogenetic soil humus, soil properties, and PAHs in B. chinensis were comprehensively studied. Mobile fulvic acid (FA) and crude humin preferred adsorbing 3-ring and 4-ring PAHs whereas stable humic acid (HA) preferred adsorbing 5-ring PAHs. The PAH speciation in soils was in the order of organic solvent extractable PAHs (59.08%)>humin-bound PAHs (26.20%)>FA-bound PAHs (10.03%)>HA-bound PAHs (4.68%). The relative amounts of FA-bound PAHs versus HA-bound PAHs were linked to soil type. FA-bound PAHs and humin mineral-bound PAHs had a positive correlation with fine particles and were preferentially accumulated in B. chinensis. Other speciation was preferentially retained in soils and adsorbed onto the surface of and within coarse particles. The PAHs in vegetables were ideally forecasted using solvent extractable PAHs, FA-bound PAHs, and soil properties (silt, moisture, and pH). The FA-bound PAHs were more soluble in water and can be easily taken up by plants together with water and nutrients.

  14. Evaluation of Thematic Mapper for detecting soil properties under grassland vegetation

    NASA Technical Reports Server (NTRS)

    Thompson, D. R.; Henderson, K. E.

    1984-01-01

    Analysis of Thematic Mapper data acquired November 15, 1982, over a vegetated site located in the East Texas Timberlands and Claypan area of Texas has indicated that montmorillonitic clay textured soils can be separated from soils with different textures. The difference of TM band 4 (0.76-0.90 micron) and band 7 (2.08-2.35 microns) had an agreement of 55.8 percent with the USDA soil survey for upland clay soils. This compared to 55.9-percent agreement when all six bands (excluding the thermal) were used. The disagreement occurred at the boundary lines as defined by the USDA soil survey and the spectral data. This result is considered to be fairly good, considering the difficulty in placement of soil boundaries by the soil scientist in the field. While the exact influence on the vegetation, and thus the spectral response observed by TM, is not understood at this time, it appears that TM band 7 is responding to the type of mineralogy of the soil and that soil properties important to the plant can be detected using TM.

  15. Atmospheric carbon exchange associated with vegetation and soils in urban and suburban land uses

    SciTech Connect

    Rowntree, R.A.

    1993-12-31

    In studies of the global C cycle prior to the 1980s, urban ecosystems were largely ignored, in part because them were inadequate measures of phytomass and soil carbon for the various land uses associated with cities. In the last decade, progress has been made in gathering urban vegetation data and recently, estimates of urban land use carbon storage and fluxes have been attempted. Demographic trends in many countries suggest that urban areas are growing. Thus it is important to discover the appropriate concepts and methods for understanding greenhouse gas fluxes from urban-related vegetation and soils.

  16. SIR-C Measurements of Soil Moisture, Vegetation and Surface Roughness and their Hydrological Application

    NASA Technical Reports Server (NTRS)

    Wang, James R.

    1996-01-01

    The objectives of the study are: (1) Analysis of SIR-C/X-SAR response to soil moisture, vegetation and surface roughness and development of an algorithm to retrieve these parameters; (2) Combination of the visible and near-infrared data and the SIR-C/X-SAR data to improve the range and accuracy of vegetation classification; (3) Testing of theoretical models for microwave propagation with SIR-C/X-SAR and microwave radiometric measurements over rough surfaces; and (4) Evaluation of a water balance model using SIR-C/X-SAR derived soil moisture values and other ancillary data. Progress, significant results and future plans are presented.

  17. Continuous measurements of net CO2 exchange by vegetation and soils in a suburban landscape

    NASA Astrophysics Data System (ADS)

    Peters, Emily B.; McFadden, Joseph P.

    2012-09-01

    In a suburban neighborhood of Minneapolis-Saint Paul, Minnesota, USA, we simultaneously measured net CO2 exchange of trees using sap flow and leaf gas exchange measurements, net CO2exchange of a turfgrass lawn using eddy covariance from a portable tower, and total surface-atmosphere CO2 fluxes (FC) using an eddy covariance system on a tall tower. Two years of continuous measurements showed that net CO2exchange varied among vegetation types, with the largest growing-season (Apr-Nov) net CO2 uptake on a per cover area basis from evergreen needleleaf trees (-603 g C m-2), followed by deciduous broadleaf trees (-216 g C m-2), irrigated turfgrass (-211 g C m-2), and non-irrigated turfgrass (-115 g C m-2). Vegetation types showed seasonal patterns of CO2exchange similar to those observed in natural ecosystems. Scaled-up net CO2 exchange from vegetation and soils (FC(VegSoil)) agreed closely with landscape FC measurements from the tall tower at times when fossil fuel emissions were at a minimum. Although FC(VegSoil) did not offset fossil fuel emissions on an annual basis, the temporal pattern of FC(VegSoil) did significantly alter the seasonality of FC. Total growing season FC(VegSoil)in recreational land-use areas averaged -165 g C m-2 and was dominated by turfgrass CO2 exchange (representing 77% of the total), whereas FC(VegSoil) in residential areas averaged -124 g C m-2 and was dominated by trees (representing 78% of the total). Our results suggest urban vegetation types can capture much of the variability required to predict seasonal patterns and differences in FC(VegSoil) that could result from changes in land use or vegetation composition in temperate cities.

  18. Response of Soil Fungi Community Structure to Salt Vegetation Succession in the Yellow River Delta.

    PubMed

    Wang, Yan-Yun; Guo, Du-Fa

    2016-10-01

    High-throughput sequencing technology was used to reveal the composition and distribution of fungal community structure in the Yellow River Delta under bare land and four kinds of halophyte vegetation (saline seepweed, Angiospermae, Imperata and Apocynum venetum [A. venetum]). The results showed that the soil quality continuously improved with the succession of salt vegetation types. The soil fungi richness of mild-salt communities (Imperata and A. venetum) was relatively higher, with Shannon index values of 5.21 and 5.84, respectively. The soil fungi richness of severe-salt-tolerant communities (saline seepweed, Angiospermae) was relatively lower, with Shannon index values of 4.64 and 4.66, respectively. The UniFrac metric values ranged from 0.48 to 0.67 when the vegetation was in different succession stages. A total of 60,174 valid sequences were obtained for the five vegetation types, and they were classified into Ascomycota, Basidiomycota, Chytridiomycota, Glomeromycota and Mucoromycotina. Ascomycota had the greatest advantage among plant communities of Imperata and A. venetum, as indicated by relative abundances of 2.69 and 69.97 %, respectively. Basidiomycota had the greatest advantage among mild-salt communities of saline seepweed and Angiospermae, with relative abundances of 9.43 and 6.64 %, respectively. Soil physical and chemical properties were correlated with the distribution of the fungi, and Mucor was significantly correlated with soil moisture (r = 0.985; P < 0.01). Soil quality, salt vegetation and soil fungi were influenced by each other.

  19. Effect of land-use practice on soil moisture variability for soils covered with dense forest vegetation of Puerto Rico

    NASA Technical Reports Server (NTRS)

    Tsegaye, T.; Coleman, T.; Senwo, Z.; Shaffer, D.; Zou, X.

    1998-01-01

    Little is known about the landuse management effect on soil moisture and soil pH distribution on a landscape covered with dense tropical forest vegetation. This study was conducted at three locations where the history of the landuse management is different. Soil moisture was measured using a 6-cm three-rod Time Domain Reflectometery (TDR) probe. Disturbed soil samples were taken from the top 5-cm at the up, mid, and foothill landscape position from the same spots where soil moisture was measured. The results showed that soil moisture varies with landscape position and depth at all three locations. Soil pH and moisture variability were found to be affected by the change in landuse management and landscape position. Soil moisture distribution usually expected to be relatively higher in the foothill (P3) area of these forests than the uphill (P1) position. However, our results indicated that in the Luquillo and Guanica site the surface soil moisture was significantly higher for P1 than P3 position. These suggest that the surface and subsurface drainage in these two sites may have been poor due to the nature of soil formation and type.

  20. [Distribution and Risk Assessment of Sulfonamides Antibiotics in Soil and Vegetables from Feedlot Livestock].

    PubMed

    Jin, Cai-xia; Si, Xiao-wei; Wang, Zi-ying; Zhang, Qin-wen

    2016-04-15

    Soil and vegetable samples were collected from 13 different livestock farms of different sizes in Xinxiang of China, and the residues of three sulfonamides including sulfadiazine, sulfamonomethoxine, and sulfamethoxazole were analyzed by HPLC with a fluorimetric detector, The results indicated that the total concentration ranges of the three sulfonamides in soil and vegetable were 7.60-176.26 µg · kg⁻¹ and ND-32, 70 µg · kg⁻¹, respectively. The mean concentrations were 70.73 µg · kg⁻¹ and 7.08 µg · kg⁻¹ for soil and vegetables. The residue levels in soil were all lower than the ecotoxic effect trigger value (100 µg · kg⁻¹) set by the Veterinary Medicine International Coordination Commission, indicating the low risk for organisms in soil. The concentrations of three sulfonamides varied significantly in different kinds of vegetables and were all lower than the acceptable daily intake values [50 µg · (kg ·d)⁻¹] set by Joint FAO/WHO Expert CommIttee on Food Additives. But we cannot neglect the potential ecotoxicity and resistance for human via food chain.

  1. Soil moisture and evapotranspiration of wetlands vegetation habitats retrieved from satellite images

    NASA Astrophysics Data System (ADS)

    Dabrowska-Zielinska, K.; Budzynska, M.; Kowalik, W.; Turlej, K.

    2010-08-01

    The research has been carried out in Biebrza Ramsar Convention test site situated in the N-E part of Poland. Data from optical and microwave satellite images have been analysed and compared to the detailed soil-vegetation ground truth measurements conducted during the satellite overpasses. Satellite data applied for the study include: ENVISAT.ASAR, ENVISAT.MERIS, ALOS.PALSAR, ALOS.AVNIR-2, ALOS.PRISM, TERRA.ASTER, and NOAA.AVHRR. Optical images have been used for classification of wetlands vegetation habitats and vegetation surface roughness expressed by LAI. Also, heat fluxes have been calculated using NOAA.AVHRR data and meteorological data. Microwave images have been used for the assessment of soil moisture. For each of the classified wetlands vegetation habitats the relationship between soil moisture and backscattering coefficient has been examined, and the best combination of microwave variables (wave length, incidence angle, polarization) has been used for mapping and monitoring of soil moisture. The results of this study give possibility to improve models of water cycle over wetlands ecosystems by adding information about soil moisture and surface heat fluxes derived from satellite images. Such information is very essential for better protection of the European sensitive wetland ecosystems. ENVISAT and ALOS images have been obtained from ESA for AO ID 122 and AOALO.3742 projects.

  2. Extraction of soil and vegetation parameters from high resolution bi-directional reflectance spectra

    NASA Technical Reports Server (NTRS)

    Huete, A. R.

    1992-01-01

    High spectral resolution reflectance spectra were collected over a semi-desert grassland at both dry and wet season periods. Spectral reflectance measurements were made from several viewing angles at both low and high solar zenith angles. A mixture model was used to separate and extract green vegetation from dry/dead vegetation and soil. The extracted vegetation signal varied greatly with view and sun angle variations such that off-nadir viewing and illuminating angles resulted in the highest vegetation loadings. These variations were normalized with cosine functions for both sun and view angle. These results offer a methodology for standardizing multi-temporal and multi-angular satellite measurements of vegetation activity.

  3. Activated carbon adsorption of PAHs from vegetable oil used in soil remediation.

    PubMed

    Gong, Zongqiang; Alef, Kassem; Wilke, Berndt-Michael; Li, Peijun

    2007-05-08

    Vegetable oil has been proven to be advantageous as a non-toxic, cost-effective and biodegradable solvent to extract polycyclic aromatic hydrocarbons (PAHs) from contaminated soils for remediation purposes. The resulting vegetable oil contained PAHs and therefore required a method for subsequent removal of extracted PAHs and reuse of the oil in remediation processes. In this paper, activated carbon adsorption of PAHs from vegetable oil used in soil remediation was assessed to ascertain PAH contaminated oil regeneration. Vegetable oils, originating from lab scale remediation, with different PAH concentrations were examined to study the adsorption of PAHs on activated carbon. Batch adsorption tests were performed by shaking oil-activated carbon mixtures in flasks. Equilibrium data were fitted with the Langmuir and Freundlich isothermal models. Studies were also carried out using columns packed with activated carbon. In addition, the effects of initial PAH concentration and activated carbon dosage on sorption capacities were investigated. Results clearly revealed the effectiveness of using activated carbon as an adsorbent to remove PAHs from the vegetable oil. Adsorption equilibrium of PAHs on activated carbon from the vegetable oil was successfully evaluated by the Langmuir and Freundlich isotherms. The initial PAH concentrations and carbon dosage affected adsorption significantly. The results indicate that the reuse of vegetable oil was feasible.

  4. Exploring field vegetation reflectance as an indicator of soil contamination in river floodplains.

    PubMed

    Kooistra, L; Salas, E A L; Clevers, J G P W; Wehrens, R; Leuven, R S E W; Nienhuis, P H; Buydens, L M C

    2004-01-01

    This study investigated the relation between vegetation reflectance and elevated concentrations of the metals Ni, Cd, Cu, Zn and Pb in river floodplain soils. High-resolution vegetation reflectance spectra in the visible to near-infrared (400-1350 nm) were obtained using a field radiometer. The relations were evaluated using simple linear regression in combination with two spectral vegetation indices: the Difference Vegetation Index (DVI) and the Red-Edge Position (REP). In addition, a multivariate regression approach using partial least squares (PLS) regression was adopted. The three methods achieved comparable results. The best R(2) values for the relation between metals concentrations and vegetation reflectance were obtained for grass vegetation and ranged from 0.50 to 0.73. Herbaceous species displayed a larger deviation from the established relationships, resulting in lower R(2) values and larger cross-validation errors. The results corroborate the potential of hyperspectral remote sensing to contribute to the survey of elevated metal concentrations in floodplain soils under grassland using the spectral response of the vegetation as an indicator. Additional constraints will, however, have to be taken into account, as results are resolution- and location-dependent.

  5. Derivation of a global soil moisture and vegetation database from passive microwave signals

    NASA Astrophysics Data System (ADS)

    De Jeu, Richard A. M.; Owe, Manfred

    2003-03-01

    A series of validation studies for a recently developed soil moisture retrieval algorithm is presented. The approach is largely theoretical, and uses a non-linear iterative optimisation procedure to solve for soil moisture and vegetation optical depth with a radiative transfer model from satellite microwave observations. The new theoretical approach is not dependent on field observations of soil moisture or canopy biophysical measurements and can be used at any wavelength in the microwave region. Details of the model and its development are discussed. Satellite retrievals were derived from 6.6 GHz Nimbus/SMMR brightness temperatures, and were validated with soil moisture data sets from the U.S., Mongolia, and Turkmenistan. Time series of the satellite-derived surface moisture compared well with the available ground observations and precipitation data. The vegetation optical depth showed similar seasonal patterns as the NDVI.

  6. Infrared temperature measurements over bare soil and vegetation - A HAPEX perspective

    NASA Technical Reports Server (NTRS)

    Carlson, Toby N.; Perry, Eileen M.; Taconet, Odile

    1987-01-01

    Preliminary analyses of aircraft and ground measurements made in France during the HAPEX experiment show that horizontal radiometric surface temperature variations, as viewed by aircraft, can reflect the vertical profile of soil moisture (soil versus root zone) because of horizontal variations in vegetation density. Analyses based on one day's data show that, although horizontal variations in soil moisture were small, the vertical differences between a dry surface and a wet root zone were large. Horizontal temperature differences between bare soil, corn and oats reflect differences in the fractional vegetation cover, as seen by the radiometer. On the other hand, these horizontal variations in radiometric surface temperature seem to reflect real horizontal variations in surface turbulent energy fluxes.

  7. Using high-resolution radar images to determine vegetation cover for soil erosion assessments.

    PubMed

    Bargiel, D; Herrmann, S; Jadczyszyn, J

    2013-07-30

    Healthy soils are crucial for human well-being. Because soils are threatened worldwide, politicians recognize the need for soil protection. For example, the European Commission has launched the Thematic Strategy for Soil Protection, which requests the European member states to identify high risk areas for soil degradation. Most states use the Universal Soil Loss Equation (USLE) to assess soil erosion risk at the national scale. The USLE includes different factors, one of them is the vegetation cover and management factor (C factor). Modern satellite-based radar sensors now provide highly accurate vegetation cover data, enabling opportunities to improve the accuracy of the C factor. The presented study proves the suitability for C factor determination based on a multi-temporal classification of high-resolution radar images. Further USLE factors were derived from existing data sources (meteorological data, soil maps, digital elevation model) to conduct an USLE-based soil erosion assessment. The resulting map illustrates a qualitative assessment for soil erosion risk within a plot of about 7*12 km in an agricultural region in Poland that is very susceptible to soil erosion processes. A high erosion risk of more than 10 tonnes per ha and year was assessed to occur on 13.6% (646 ha) of the agricultural areas within the investigated plot. Further 7.8% (372 ha) of agricultural land is threaten by a medium risk of 5-10 tonnes per ha and year. Such a spatial information about areas of high or medium soil erosion risk are crucial for the development of strategies for the protection of soils.

  8. Organochlorine pesticides in soils and air of southern Mexico: Chemical profiles and potential for soil emissions

    NASA Astrophysics Data System (ADS)

    Wong, Fiona; Alegria, Henry A.; Jantunen, Liisa M.; Bidleman, Terry F.; Salvador-Figueroa, Miguel; Gold-Bouchot, Gerardo; Ceja-Moreno, Victor; Waliszewski, Stefan M.; Infanzon, Raul

    The extent of organochlorine pesticides (OCs) contamination in southern Mexico was investigated in this study. Biweekly air samplings were carried out in two sites in the state of Chiapas (during 2002-2003), and one in each state of Veracruz and Tabasco (during 2003-2004). Corresponding to the air sampling locations, soil samples were also collected to gauge the soil-air exchange of OCs in the region. ∑DDTs in soils ranged from 0.057 to 360 ng g -1 whereas those in air ranged from 240 to 2400 pg m -3. DDT and metabolite DDE were expressed as fractional values, FDDTe = p, p'-DDT/( p, p'-DDT + p, p'-DDE) and FDDTo = p,p'-DDT/( p,p'-DDT + o,p'-DDT). FDDTe in soils ranged from 0.30 to 0.69 while those in air ranged from 0.45 to 0.84. FDDTe in air at a farm in Chiapas (0.84) was closer to that of technical DDT (0.95) which is suggestive of fresh DDT input. Enantiomer fractions (EF) of o,p'-DDT in air were racemic at all locations (0.500-0.504). However, nonracemic o,p'-DDT was seen in the soils (EFs = 0.456-0.647). Fugacities of OCs in soil ( fs) and air ( fa) were calculated, and the fugacity fraction, ff = fs/( fs + fa) of DDTs ranged from 0.013 to 0.97 which indicated a mix of net deposition ( ff < 0.5) and volatilization ( ff > 0.5) from soil among the sites. It is suggested that DDTs in Mexico air are due to a combination of ongoing regional usage and re-emission of old DDT residues from soils. Total toxaphene in soils ranged from 0.066 to 69 ng g -1 while levels in air ranged from 6.2 to 230 pg m -3. Chromatographic profiles of toxaphenes in both air and soil showed depletion of Parlar congeners 39 and 42. Fugacity fractions of toxaphene were within the equilibrium range or above the upper equilibrium threshold boundary. These findings suggested that soil emission of old residues is the main source of toxaphenes to the atmosphere. Results from this study provide baseline data for establishing a long-term OC monitoring program in Mexico.

  9. River basin soil-vegetation condition assessment applying mathematic simulation methods

    NASA Astrophysics Data System (ADS)

    Mishchenko, Natalia; Trifonova, Tatiana; Shirkin, Leonid

    2013-04-01

    Meticulous attention paid nowadays to the problem of vegetation cover productivity changes is connected also to climate global transformation. At the same time ecosystems anthropogenic transformation, basically connected to the changes of land use structure and human impact on soil fertility, is developing to a great extent independently from climatic processes and can seriously influence vegetation cover productivity not only at the local and regional levels but also globally. Analysis results of land use structure and soil cover condition influence on river basin ecosystems productive potential is presented in the research. The analysis is carried out applying integrated characteristics of ecosystems functioning, space images processing results and mathematic simulation methods. The possibility of making permanent functional simulator defining connection between macroparameters of "phytocenosis-soil" system condition on the basis of basin approach is shown. Ecosystems of river catchment basins of various degrees located in European part of Russia were chosen as research objects. For the integrated assessment of ecosystems soil and vegetation conditions the following characteristics have been applied: 1. Soil-productional potential, characterizing the ability of natural and natural-anthropogenic ecosystem in certain soil-bioclimatic conditions for long term reproduction. This indicator allows for specific phytomass characteristics and ecosystem produce, humus content in soil and bioclimatic parameters. 2. Normalized difference vegetation index (NDVI) has been applied as an efficient, remotely defined, monitoring indicator characterizing spatio-temporal unsteadiness of soil-productional potential. To design mathematic simulator functional simulation methods and principles on the basis of regression, correlation and factor analysis have been applied in the research. Coefficients values defining in the designed static model of phytoproductivity distribution has been

  10. Runoff loss of pesticides and soil: a comparison between vegetative mulch and plastic mulch in vegetable production systems.

    PubMed

    Rice, P J; McConnell, L L; Heighton, L P; Sadeghi, A M; Isensee, A R; Teasdale, J R; Abdul-Baki, A A; Harman-Fetcho, J A; Hapeman, C J

    2001-01-01

    Current vegetable production systems use polyethylene (plastic) mulch and require multiple applications of agrochemicals. During rain events, runoff from vegetable production is enhanced because 50 to 75% of the field is covered with an impervious surface. This study was conducted to quantify off-site movement of soil and pesticides with runoff from tomato (Lycopersicon esculentum Mill.) plots containing polyethylene mulch and a vegetative mulch, hairy vetch (Vicia villosa Roth). Side-by-side field plots were instrumented with automated flow meters and samplers to measure and collect runoff, which was filtered, extracted, and analyzed to determine soil and pesticide loss. Seasonal losses of two to four times more water and at least three times as much sediment were observed from plots with polyethvlene mulch (55.4 to 146 L m(-2) and 247 to 535 g m(-2), respectively) versus plots with hairy vetch residue (13.7 to 75.7 L m(-2) and 32.8 to 118 g m(-2), respectively). Geometric means (+/-standard deviation) of total pesticide loads for chlorothalonil (tetrachloroisophthalonitrile) and alpha-and beta-endosulfan (6,7,8,9,10,10-hexachloro-1,5,5a,6,9,9a-hexahydro6,9-methano-2,4,3-benzodioxathiepin 3-oxide) for a runoff event were 19, 6, and 9 times greater from polyethylene (800+/-4.6, 17.6+/-3.9, and 39.1+/-4.9 microg m(-2), respectively) than from hairy vetch mulch plots (42+/-6.0, 2.8+/-5.0, and 4.3+/-4.6 microg m(-2), respectively) due to greater concentrations and larger runoff volumes. The increased runoff volume, soil loss, and off-site loading of pesticides measured in runoff from the polyethylene mulch suggests that this management practice is less sustainable and may have a harmful effect on the environment.

  11. Effects of vegetation on radon transport processes in soil

    SciTech Connect

    Borak, T.B.

    1991-02-01

    Radon concentrations in soil gas were measured on a weekly schedule. Samples were extracted through the tubes used for measuring pressure differentials at depths of 30, 100, 180 cm. From November to March, the concentrations increase with depth and are for the most part constant over time. The situation is similar from May through August. There is a pronounced increase in the soil radon concentration in early March. This is followed by a decrease to pre March levels at 30 cm. However, at 100 and 180 cm the radon concentrations remain elevated. Attempts were made to explain this data. The average soil moisture content measured with the neutron gauge are shown in Figure 2. Also shown is a history of precipitation events. The period from November to March was relatively dry. On March 6 there was a heavy rain deposited 3 cm of water. This was followed by a snow storm that contained over 5 cm of moisture. Precipitation events during the summer months did not seem to have a large effect on the moisture profile because these rainfall events are typical of short duration with a large amount of runoff. Other soil parameters and meteorological data were analyzed in order to determine their influence on soil radon concentrations.

  12. Methane emissions from upland forest soils and vegetation.

    PubMed

    Megonigal, J Patrick; Guenther, Alex B

    2008-04-01

    Most work on methane (CH(4)) emissions from natural ecosystems has focused on wetlands because they are hotspots of CH(4) production. Less attention has been directed toward upland ecosystems that cover far larger areas, but are assumed to be too dry to emit CH(4). Here we review CH(4) production and emissions in upland ecosystems, with attention to the influence of plant physiology on these processes in forests. Upland ecosystems are normally net sinks for atmospheric CH(4) because rates of CH(4) consumption exceed CH(4) production. Production of CH(4) in upland soils occurs in microsites and may be common in upland forest soils. Some forests switch from being CH(4) sinks to CH(4) sources depending on soil water content. Plant physiology influences CH(4) cycling by modifying the availability of electron donors and acceptors in forest soils. Plants are the ultimate source of organic carbon (electron donor) that microbes process into CH(4). The availability of O(2) (electron acceptor) is sensitive to changes in soil water content, and therefore, to transpiration rates. Recently, abiotic production of CH(4) from aerobic plant tissue was proposed, but has not yet been verified with independent data. If confirmed, this new source is likely to be a minor term in the global CH(4) budget, but important to quantify for purposes of greenhouse gas accounting. A variety of observations suggest that our understanding of CH(4) sources in upland systems is incomplete, particularly in tropical forests which are stronger sources then expected.

  13. Reorganization of vegetation, hydrology and soil carbon after permafrost degradation across heterogeneous boreal landscapes

    USGS Publications Warehouse

    Jorgenson, M. Torre; Harden, Jennifer; Kanevskiy, Mikhail; O'Donnell, Jonathan; Wickland, Kim; Ewing, Stephanie; Manies, Kristen; Zhuang, Qianlai; Shur, Yuri; Striegl, Robert; Koch, Josh

    2013-01-01

    The diversity of ecosystems across boreal landscapes, successional changes after disturbance and complicated permafrost histories, present enormous challenges for assessing how vegetation, water and soil carbon may respond to climate change in boreal regions. To address this complexity, we used a chronosequence approach to assess changes in vegetation composition, water storage and soil organic carbon (SOC) stocks along successional gradients within four landscapes: (1) rocky uplands on ice-poor hillside colluvium, (2) silty uplands on extremely ice-rich loess, (3) gravelly–sandy lowlands on ice-poor eolian sand and (4) peaty–silty lowlands on thick ice-rich peat deposits over reworked lowland loess. In rocky uplands, after fire permafrost thawed rapidly due to low ice contents, soils became well drained and SOC stocks decreased slightly. In silty uplands, after fire permafrost persisted, soils remained saturated and SOC decreased slightly. In gravelly–sandy lowlands where permafrost persisted in drier forest soils, loss of deeper permafrost around lakes has allowed recent widespread drainage of lakes that has exposed limnic material with high SOC to aerobic decomposition. In peaty–silty lowlands, 2–4 m of thaw settlement led to fragmented drainage patterns in isolated thermokarst bogs and flooding of soils, and surface soils accumulated new bog peat. We were not able to detect SOC changes in deeper soils, however, due to high variability. Complicated soil stratigraphy revealed that permafrost has repeatedly aggraded and degraded in all landscapes during the Holocene, although in silty uplands only the upper permafrost was affected. Overall, permafrost thaw has led to the reorganization of vegetation, water storage and flow paths, and patterns of SOC accumulation. However, changes have occurred over different timescales among landscapes: over decades in rocky uplands and gravelly–sandy lowlands in response to fire and lake drainage, over decades to

  14. Root-soil air gap and resistance to water flow at the soil-root interface of Robinia pseudoacacia.

    PubMed

    Liu, X P; Zhang, W J; Wang, X Y; Cai, Y J; Chang, J G

    2015-12-01

    During periods of water deficit, growing roots may shrink, retaining only partial contact with the soil. In this study, known mathematical models were used to calculate the root-soil air gap and water flow resistance at the soil-root interface, respectively, of Robinia pseudoacacia L. under different water conditions. Using a digital camera, the root-soil air gap of R. pseudoacacia was investigated in a root growth chamber; this root-soil air gap and the model-inferred water flow resistance at the soil-root interface were compared with predictions based on a separate outdoor experiment. The results indicated progressively greater root shrinkage and loss of root-soil contact with decreasing soil water potential. The average widths of the root-soil air gap for R. pseudoacacia in open fields and in the root growth chamber were 0.24 and 0.39 mm, respectively. The resistance to water flow at the soil-root interface in both environments increased with decreasing soil water potential. Stepwise regression analysis demonstrated that soil water potential and soil temperature were the best predictors of variation in the root-soil air gap. A combination of soil water potential, soil temperature, root-air water potential difference and soil-root water potential difference best predicted the resistance to water flow at the soil-root interface.

  15. [Characteristics of soil organic carbon and enzyme activities in soil aggregates under different vegetation zones on the Loess Plateau].

    PubMed

    Li, Xin; Ma, Rui-ping; An, Shao-shan; Zeng, Quan-chao; Li, Ya-yun

    2015-08-01

    In order to explore the distribution characteristics of organic carbon of different forms and the active enzymes in soil aggregates with different particle sizes, soil samples were chosen from forest zone, forest-grass zone and grass zone in the Yanhe watershed of Loess Plateau to study the content of organic carbon, easily oxidized carbon, and humus carbon, and the activities of cellulase, β-D-glucosidase, sucrose, urease and peroxidase, as well as the relations between the soil aggregates carbon and its components with the active soil enzymes were also analyzed. It was showed that the content of organic carbon and its components were in order of forest zone > grass zone > forest-grass zone, and the contents of three forms of organic carbon were the highest in the diameter group of 0.25-2 mm. The content of organic carbon and its components, as well as the activities of soil enzymes were higher in the soil layer of 0-10 cm than those in the 10-20 cm soil layer of different vegetation zones. The activities of cellulase, β-D-glucosidase, sucrose and urease were in order of forest zone > grass zone > forest-grass zone. The peroxidase activity was in order of forest zone > forest-grass zone > grass zone. The activities of various soil enzymes increased with the decreasing soil particle diameter in the three vegetation zones. The activities of cellulose, peroxidase, sucrose and urease had significant positive correlations with the contents of various forms of organic carbon in the soil aggregates.

  16. Soil, water, and vegetation conditions in South Texas

    NASA Technical Reports Server (NTRS)

    Wiegand, C. L.; Gausman, H. W.; Leamer, R. W.; Richardson, A. J.; Everitt, J. H.; Gerbermann, A. H. (Principal Investigator)

    1976-01-01

    The author has identified the following significant results. Reflectance measurements with a field spectroradiometer on nine dates (between December 9 and April 8) during the growing season of two wheat varieties, Milam and Penjamo, showed that the reflectance curves had the characteristic shape of vegetated surfaces by 4 weeks after the emergence. Green light (0.55 micron) reflectance was maximal and between water absorption bands (1.65 and 2.2 microns) reflectance was minimal when green vegetation development was greatest. Computer classification was accomplished for 81,000 hectare coastal rangeland area for October 13 and December 10, 1975, overpass dates. A hard freeze occurred between these two dates and many of the deciduous woody species defoliated so that more light penetrated to the herbaceous understory in December than in October.

  17. Vegetation, soil property and climatic controls over greenhouse gas fluxes in a blanket peatland hosting a wind farm

    NASA Astrophysics Data System (ADS)

    Armstrong, Alona; Waldron, Susan; Ostle, Nick; Whitaker, Jeanette

    2013-04-01

    Peatlands are important carbon (C) stores, with boreal and subarctic peatlands containing 15-30 % of the world soil carbon stock (Limpens et al., 2008). Research has demonstrated that greenhouse gas (GHG) fluxes in peatlands are influenced by vegetation, soil property and climatic variables, including plant functional type (PFT), water table height and temperature. In this paper we present data from Black Law Wind Farm, Scotland, where we examined the effect of a predicted wind turbine-induced microclimatic gradient and PFT on carbon dioxide (CO2) and methane (CH4) fluxes. Moreover, we determined the role of vegetation, soil property and climatic variables as predictors of the variation in CO2 and CH4 emissions. We measured CO2 and CH4 at 48 plots within Black Law Wind Farm at monthly intervals from May 2011 to April 2012. Four sampling sites were located along a predicted wind turbine-induced microclimatic gradient. At each site four blocks were established, each with plots in areas dominated by mosses, sedges and shrubs. Plant biomass and PFT (vegetation factors); soil moisture, water table height, peat depth, C content, nitrogen (N) content and C:N (soil properties); and soil temperature and photosynthetically active radiation (PAR) (climatic variables) were measured. Analysis of variance (ANOVA) models based on the microclimatic gradient site, PFT and season when measurements were made explained 58 %, 44 % and 49 % of the variation in ecosystem respiration, photosynthesis and CH4, respectively. Site, PFT, season and their interactions were all significant for respiration and photosynthesis (with the exception of the PFT*site interaction) but for CH4 only the main effects were significant. Parsimonious ANOVA models using the biotic, soil property and climatic explanatory data explained 62 %, 55 % and 49 % of the variation in respiration, photosynthesis and CH4, respectively. Published studies (Baidya Roy and Traiteur 2010; Zhou et al., 2012) and preliminary

  18. Soil, water, and vegetation conditions in south Texas

    NASA Technical Reports Server (NTRS)

    Wiegand, C. L.; Gausman, H. W.; Leamer, R. W.; Richardson, A. J.; Everitt, J. H.; Gerbermann, A. H. (Principal Investigator)

    1976-01-01

    The author has identified the following significant results. Software development for a computer-aided crop and soil survey system is nearing completion. Computer-aided variety classification accuracies using LANDSAT-1 MSS data for a 600 hectare citrus farm were 83% for Redblush grapefruit and 91% for oranges. These accuracies indicate that there is good potential for computer-aided inventories of grapefruit and orange citrus orchards with LANDSAT-type MSS data. Mean digital values of clouds differed statistically from those for crop, soil, and water entities, and those for cloud shadows were enough lower than sunlit crop and soil to be distinguishable. The standard errors of estimate for the calibration of computer compatible tape coordinate system (pixel and record) to earth coordinate system (longitude and latitude) for 6 LANDSAT scenes ranged from 0.72 to 1.50 pixels and from 0.58 to 1.75 records.

  19. Interacting vegetative and thermal contributions to water movement in desert soil

    USGS Publications Warehouse

    Garcia, C.A.; Andraski, B.J.; Stonestrom, D.A.; Cooper, C.A.; Simunek, J.; Wheatcraft, S.W.

    2011-01-01

    Thermally driven water-vapor flow can be an important component of total water movement in bare soil and in deep unsaturated zones, but this process is often neglected when considering the effects of soil-plant-atmosphere interactions on shallow water movement. The objectives of this study were to evaluate the coupled and separate effects of vegetative and thermal-gradient contributions to soil water movement in desert environments. The evaluation was done by comparing a series of simulations with and without vegetation and thermal forcing during a 4.7-yr period (May 2001-December 2005). For vegetated soil, evapotranspiration alone reduced root-zone (upper 1 m) moisture to a minimum value (25 mm) each year under both isothermal and nonisothermal conditions. Variations in the leaf area index altered the minimum storage values by up to 10 mm. For unvegetated isothermal and nonisothermal simulations, root-zone water storage nearly doubled during the simulation period and created a persistent driving force for downward liquid fluxes below the root zone (total net flux ~1 mm). Total soil water movement during the study period was dominated by thermally driven vapor fluxes. Thermally driven vapor flow and condensation supplemented moisture supplies to plant roots during the driest times of each year. The results show how nonisothermal flow is coupled with plant water uptake, potentially influencing ecohydrologic relations in desert environments. ?? Soil Science Society of America 5585 Guilford Rd., Madison, WI 53711 USA. All rights reserved.

  20. [Effect of vegetation types on soil respiration characteristics on a smaller scale].

    PubMed

    Yan, Jun-Xia; Li, Hong-Jian; Tang, Yi; Zhang, Yi-Hui

    2009-11-01

    Soil respiration was measured from April 2005 to December 2007 using a LICOR-6400-09 chamber connecting a LiCor-6400 portable photosynthesis system at 3 sites with same elevation and soil texture but different vegetation types. The results indicated that seasonal trend of soil respiration showed a distinct temporal change with the higher values in summer and autumn months and the lower values in winter and spring. Annual means (March to December) of soil respiration for 3 the sampling sites were(3.58 +/- 2.50), (3.82 +/- 2.75) and (4.42 +/- 3.38) micromol x (m2 x s)(-1) (p > 0.05), respectively. Released annual amount (March to December) of CO2 efflux from 3 sites was from 854.9 to 1 297.2 g x (m2 x a)(-1) and the amount was no difference between sites and among years. The fitted exponential equations of soil respiration and soil temperature for 3 sites were all significant with the R2 from 0.61 to 0.81, and the Q10 and R10 calculated from fitted parameters of the equations ranged from 2.60 to 4.50, and from 1.70 to 3.02 micromol x (m2 x s)(-1). The relationships between soil respiration and soil water content were not significant for all 3 sites with a maximum R2 of the regression equations only 0.12 (p > 0.05). However, when the soil temperature was above 10 degrees C, the relationships between soil respiration and soil water content was significant (p < 0.05). Four combined regression equations including soil temperature and soil water content could be used to model relationships between soil respiration and both soil temperature and soil water content together, with the R2 most above 0.7, and maximum of 0.91.

  1. The co-evolution and spatial organisation of soils, landforms, vegetation, and hydrology

    NASA Astrophysics Data System (ADS)

    Willgoose, G. R.; Cohen, S.; Hancock, G. R.; Hobley, E. U.; Saco, P. M.

    2012-12-01

    Soils are the intermediary for many important environmental processes, and in many cases may be a significant driver of the response of these processes. Moreover the soils themselves are a response (over pedogenic timescales) to these same environmental processes. Soil timescales range from decades (for some fractions of soils carbon, and microbiological processes) through millennia (for vegetation and other fractions of soil carbon) to millions of years (for soil response to landforms). Thus that if we are to model pedogenesis in an attempt to understand the spatial distribution of soils (hillslope, catchment, or landscape scales) and their dynamic response (as for instance drivers of sediment load for basin subsidence analysis) we will need to quantify timescale of response and spatial and temporal links of the process dynamics of pedogenesis, landform evolution, vegetation and hydrology. This presentation summarises progress in our group in this coupling of processes across disparate time and space scales. We will show data that we have collected for pedogenesis, soil carbon and landforms that identify timescales for different components of the processes, and computer simulations where we have inferred other timescales from process response. We will present a framework which we believe will allow us to simplify the complexity of the spatial and temporal coupling by using spatial and temporal scale breaks in the processes.

  2. Relationships between soil microbial communities and soil carbon turnover along a vegetation and moisture gradient in interior Alaska

    NASA Astrophysics Data System (ADS)

    Waldrop, M. P.; Harden, J. W.; Turetsky, M. R.; Petersen, D. G.; McGuire, A. D.; Briones, M. J.; Churchill, A. C.; Doctor, D. H.; Pruett, L. E.

    2010-12-01

    Boreal landscapes are characterized by a mosaic of uplands and lowlands, which differ in plant species composition, litter biochemistry, and biogeochemical cycling rates. Boreal ecosystems, from upland black spruce stands to lowland fens, are structured largely by water table position and contain quantitatively and qualitatively different forms of soil organic matter. Differences in carbon (C) availability among ecosystems likely translate to differences in the structure of soil microbial communities, which in turn could affect rates of organic matter decomposition and turnover. We examined relationships between microbial communities and soil C turnover in near-surface soils along a topographic soil moisture and vegetation gradient in interior Alaska. We tested the hypothesis that upland black spruce sites would be dominated by soil fungi and have slow rates of C turnover, whereas lowland ecosystems would be dominated by bacteria and mesofauna (enchytraeids) and have more rapid rates of C turnover. We utilized several isotopic measures of soil C turnover including bomb radiocarbon techniques, the δ15N of SOM, and the difference between δ13C of SOM, DOC, and respired CO2. All three measures indicated greater C turnover rates in the surface soils of the lowland fen sites compared to the more upland locations. Quantitative PCR analyses of soil bacteria and archaea, combined with enchytraed counts, confirmed that surface soils from the lowland fen ecosystems had the highest abundances of these functional groups. Fungal biomass was highly variable and tended to be more abundant in the upland forest sites. Soil enzymatic results were mixed: potential cellulase activities were higher in the more upland soils even though rates of microbial activity were generally lower. Oxidative enzyme activities were higher in fens, even though these ecosystems are saturated and partly anaerobic. Overall our data support soil food web theory which argues that rapidly cycling systems

  3. Effect of grazing on vegetation and soil of the heuweltjieveld in the Succulent Karoo, South Africa

    NASA Astrophysics Data System (ADS)

    Schmiedel, Ute; Röwer, Inga Ute; Luther-Mosebach, Jona; Dengler, Jürgen; Oldeland, Jens; Gröngröft, Alexander

    2016-11-01

    We asked how historical and recent grazing intensity affect the patchy landscape of the heuweltjieveld in the semi-arid biodiversity hotspot Succulent Karoo. The study was carried out on a communal farmland 80 km south-west of Springbok, in Namaqualand. Heuweltjies are roughly circular earth mounds that are regularly distributed in this landscape. We sampled plant species and life-form composition, diversity measures, habitat and soil variables in 100 m2 plots, placed in three visually distinguishable heuweltjie zones (centre, fringe, and matrix) and distributed across grazing camps with different recent and historic grazing intensities. Differences between heuweltjie zones were assessed with ANOVAs and multiple linear regressions. The effect of past and recent grazing intensity on soil and plant variables was analysed by Generalized Linear Models for each heuweltjie zone separately. The three zones constituted clearly distinguishable units in terms of vegetation and soil characteristics. Soil pH and cover of annual plants increased from matrix to centres, while total vegetation cover, species richness and perennial plant cover decreased in the same direction. Historic (pre-2000) grazing patterns had the strongest effects on fringes, showing the strongest soil and vegetation-related signs of overutilization with increased stocking density. Centres showed signs of overutilization irrespective of the stocking density. The much shorter exposure to recent grazing pattern (post-2000), which was nearly inverse to the historic grazing pattern, showed increase of vegetation cover (centres) and species richness (matrix) with recent grazing intensity. We interpret these effects as still visible responses of the lower grazing intensity in these camps during the historic period. No recovery under recent grazing was observed at any of the zones. We conclude that irrespective of their conducive growing conditions, once transformed to a disturbed state, heuweltjie centres recover

  4. Soil TPH concentration estimation using vegetation indices in an oil polluted area of eastern China.

    PubMed

    Zhu, Linhai; Zhao, Xuechun; Lai, Liming; Wang, Jianjian; Jiang, Lianhe; Ding, Jinzhi; Liu, Nanxi; Yu, Yunjiang; Li, Junsheng; Xiao, Nengwen; Zheng, Yuanrun; Rimmington, Glyn M

    2013-01-01

    Assessing oil pollution using traditional field-based methods over large areas is difficult and expensive. Remote sensing technologies with good spatial and temporal coverage might provide an alternative for monitoring oil pollution by recording the spectral signals of plants growing in polluted soils. Total petroleum hydrocarbon concentrations of soils and the hyperspectral canopy reflectance were measured in wetlands dominated by reeds (Phragmites australis) around oil wells that have been producing oil for approximately 10 years in the Yellow River Delta, eastern China to evaluate the potential of vegetation indices and red edge parameters to estimate soil oil pollution. The detrimental effect of oil pollution on reed communities was confirmed by the evidence that the aboveground biomass decreased from 1076.5 g m(-2) to 5.3 g m(-2) with increasing total petroleum hydrocarbon concentrations ranging from 9.45 mg kg(-1) to 652 mg kg(-1). The modified chlorophyll absorption ratio index (MCARI) best estimated soil TPH concentration among 20 vegetation indices. The linear model involving MCARI had the highest coefficient of determination (R(2) = 0.73) and accuracy of prediction (RMSE = 104.2 mg kg(-1)). For other vegetation indices and red edge parameters, the R(2) and RMSE values ranged from 0.64 to 0.71 and from 120.2 mg kg(-1) to 106.8 mg kg(-1) respectively. The traditional broadband normalized difference vegetation index (NDVI), one of the broadband multispectral vegetation indices (BMVIs), produced a prediction (R(2) = 0.70 and RMSE = 110.1 mg kg(-1)) similar to that of MCARI. These results corroborated the potential of remote sensing for assessing soil oil pollution in large areas. Traditional BMVIs are still of great value in monitoring soil oil pollution when hyperspectral data are unavailable.

  5. Soil TPH Concentration Estimation Using Vegetation Indices in an Oil Polluted Area of Eastern China

    PubMed Central

    Zhu, Linhai; Zhao, Xuechun; Lai, Liming; Wang, Jianjian; Jiang, Lianhe; Ding, Jinzhi; Liu, Nanxi; Yu, Yunjiang; Li, Junsheng; Xiao, Nengwen; Zheng, Yuanrun; Rimmington, Glyn M.

    2013-01-01

    Assessing oil pollution using traditional field-based methods over large areas is difficult and expensive. Remote sensing technologies with good spatial and temporal coverage might provide an alternative for monitoring oil pollution by recording the spectral signals of plants growing in polluted soils. Total petroleum hydrocarbon concentrations of soils and the hyperspectral canopy reflectance were measured in wetlands dominated by reeds (Phragmites australis) around oil wells that have been producing oil for approximately 10 years in the Yellow River Delta, eastern China to evaluate the potential of vegetation indices and red edge parameters to estimate soil oil pollution. The detrimental effect of oil pollution on reed communities was confirmed by the evidence that the aboveground biomass decreased from 1076.5 g m−2 to 5.3 g m−2 with increasing total petroleum hydrocarbon concentrations ranging from 9.45 mg kg−1 to 652 mg kg−1. The modified chlorophyll absorption ratio index (MCARI) best estimated soil TPH concentration among 20 vegetation indices. The linear model involving MCARI had the highest coefficient of determination (R2 = 0.73) and accuracy of prediction (RMSE = 104.2 mg kg−1). For other vegetation indices and red edge parameters, the R2 and RMSE values ranged from 0.64 to 0.71 and from 120.2 mg kg−1 to 106.8 mg kg−1 respectively. The traditional broadband normalized difference vegetation index (NDVI), one of the broadband multispectral vegetation indices (BMVIs), produced a prediction (R2 = 0.70 and RMSE = 110.1 mg kg−1) similar to that of MCARI. These results corroborated the potential of remote sensing for assessing soil oil pollution in large areas. Traditional BMVIs are still of great value in monitoring soil oil pollution when hyperspectral data are unavailable. PMID:23342066

  6. CO2 leakage-induced vegetation decline is primarily driven by decreased soil O2.

    PubMed

    Zhang, Xueyan; Ma, Xin; Zhao, Zhi; Wu, Yang; Li, Yue

    2016-04-15

    To assess the potential risks of carbon capture and storage (CCS), studies have focused on vegetation decline caused by leaking CO2. Excess soil CO2 caused by leakage can affect soil O2 concentrations and soil pH, but how these two factors affect plant development remains poorly understood. This hinders the selection of appropriate species to mitigate potential negative consequences of CCS. Through pot experiments, we simulated CO2 leakage to examine its effects on soil pH and soil O2 concentrations. We subsequently assessed how maize growth responded to these changes in soil pH and O2. Decreased soil O2 concentrations significantly reduced maize biomass, and explained 69% of the biomass variation under CO2 leakage conditions. In contrast, although leaked CO2 changed soil pH significantly (from 7.32 to 6.75), it remained within the optimum soil pH range for maize growth. This suggests that soil O2 concentration, not soil pH, influences plant growth in these conditions. Therefore, in case of potential CO2 leakage risks, hypoxia-tolerant species should be chosen to improve plant survival, growth, and yield.

  7. Effect of vegetation on the temporal stability of soil moisture in grass-stabilized semi-arid sand dunes

    NASA Astrophysics Data System (ADS)

    Wang, Tiejun; Wedin, David A.; Franz, Trenton E.; Hiller, Jeremy

    2015-02-01

    Soil moisture is a critical state variable affecting a variety of land surface and subsurface processes. Despite the complex interactions between soil moisture and its controlling factors, the phenomenon of temporal stability of soil moisture (TS SM) has been widely observed under natural conditions. In this study, the control of vegetation on TS SM is investigated by artificially manipulating surface vegetation (e.g., vegetated and de-vegetated plots) in a native grassland-stabilized sand dune area with similar soil texture and topography. Soil moisture data were collected at the depths of 30 cm (within the root zone) and 110 cm (below the root zone) over a period of four years. Using soil moisture data from the de-vegetated plots as a baseline, TS SM within the root zone is shown to be mainly affected by vegetation phenology at the study site. Therefore, the control of vegetation on TS SM varies on both seasonal and annual time scales. The change in the interseasonal patterns of TS SM is tightly related to plant phenology and the control of vegetation on the ranking of mean relative difference (MRD) of soil moisture significantly weakens during non-growing seasons due to diminished root water uptake. It suggests that the timing of sampling schemes (e.g., growing season vs. non-growing season) may alter TS SM patterns. On annual time scales, TS SM is affected by climatic conditions, as the control of vegetation on TS SM becomes stronger under drier conditions. In particular, vegetation tends to create larger contrasts in soil moisture levels between vegetated and de-vegetated plots in drier years. The soil moisture data also provide evidence that vegetation tends to reduce TS SM and increase spatial variability in soil moisture at the study site. The standard deviation of relative difference (SDRD) of soil moisture at the 30 cm depth (within the root zone) is considerably larger in the vegetated plots than those in the de-vegetated plots. As such, the

  8. Dissolved organic carbon (DOC) concentrations in UK soils and the influence of soil, vegetation type and seasonality.

    PubMed

    van den Berg, Leon J L; Shotbolt, Laura; Ashmore, Mike R

    2012-06-15

    Given the lack of studies which measured dissolved organic carbon (DOC) over long periods, especially in non-forest habitat, the aim of this study was to expand the existing datasets with data of mainly non-forest sites that were representative of the major soil and habitat types in the UK. A further aim was to predict DOC concentrations from a number of biotic and abiotic explanatory variables such as rainfall, temperature, vegetation type and soil type in a multivariate way. Pore water was sampled using Rhizon or Prenart samplers at two to three week intervals for 1 year. DOC, pH, organic carbon, carbon/nitrogen (C:N) ratios of soils and slope were measured and data on vegetation, soil type, temperature and precipitation were obtained. The majority of the variation in DOC concentrations between the UK sites could be explained by simple empirical models that included annual precipitation, and soil C:N ratio with precipitation being negatively related to DOC concentrations and C:N ratio being positively related to DOC concentrations. Our study adds significantly to the data reporting DOC concentrations in soils, especially in grasslands, heathlands and moorlands. Broad climatic and site factors have been identified as key factors influencing DOC concentrations.

  9. Radionuclide concentrations in terrestrial vegetation and soil on and around the Hanford Site, 1983 through 1993

    SciTech Connect

    Poston, T.M.; Antonio, E.J.; Cooper, A.T.

    1995-08-01

    This report reviews concentrations of {sup 60}Co, {sup 90}Sr, {sup 137}Cs, U isotopes, {sup 238}Pu, {sup 239,240}Pu, and {sup 241}Am in soil and vegetation samples collected from 1983 through 1993 during routine surveillance of the Hanford Site. Sampling locations were grouped in study areas associated with operational areas on the Site. While radionuclide concentrations were very low and representative of background concentrations from historic fallout, some study areas on the Site contained slightly elevated concentrations compared to other study areas onsite and offsite. The 100 Areas had concentrations of {sup 60}Co comparable to the minimum detectable concentration of 0.02 pCi/g in soil. Concentrations of {sup 90}Sr, {sup 137}Cs, {sup 238}Pu, {sup 239,240}Pu, and {sup 241}Am in 200 Area soils were slightly elevated. The 300 Area had a slight elevation of U in soil. These observations were expected because many of the sampling locations were selected to monitor specific facilities or operations at the operational areas. Generally, concentrations of the radionuclides studied were greater and more readily measured in soil samples compared to vegetation samples. The general pattern of concentrations of radionuclide concentrations in vegetation by area mirrored that observed in soil. Declines in {sup 90}Sr in soil appear to be attributed to radioactive decay and possibly downward migration out of the sampling horizon. The other radionuclides addressed in this report strongly sorb to soil and are readily retained in surface soil. Because of their long half-lives compared to the length of the study period, there was no significant indication that concentrations of U isotopes and Pu isotopes were decreasing over time.

  10. Soil seed bank recovery occurs more rapidly than expected in semi-arid Mediterranean gypsum vegetation

    PubMed Central

    Olano, J. M.; Caballero, I.; Escudero, A.

    2012-01-01

    Background and Aims Seed banks are critical in arid ecosystems and ensure the persistence of species. Despite the importance of seed banks, knowledge about their formation and the extent to which a seed bank can recover after severe perturbation remains scarce. If undisturbed, soil seed banks reflect a long vegetation history; therefore, we would expect that new soil seed banks and those of undisturbed soils require long periods to become similar with respect to both density and composition. In contrast, if soil seed banks are only a short- to mid-term reservoir in which long-term accumulation constitutes only a tiny fraction, they will recover rapidly from the vegetation. To shed light on this question, we evaluated seed bank formation in a semi-arid gypsum community. Methods Soils from 300 plots were replaced with sterilized soil in an undisturbed semi-arid Mediterranean community. Seasonal changes in seed bank density and composition were monitored for 3 years by comparing paired sterilized and control soil samples at each plot. Key Results Differences in seed bank density between sterilized and control soil disappeared after 18 months. The composition of sterilized seed banks was correlated with that of the control plots from the first sampling date, and both were highly correlated with vegetation. Nearly 24 % of the seed bank density could be attributed to secondary dispersal. Most seeds died before emergence (66·41–71·33 %), whereas the rest either emerged (14·08–15·48 %) or persisted in the soil (14·59–18·11 %). Conclusions Seed banks can recover very rapidly even under the limiting and stressful conditions of semi-arid environments. This recovery is based mainly on the seed rain at small scales together with secondary dispersal from intact seed banks in the vicinity. These results emphasize the relevance of processes occurring on short spatial scales in determining community structure. PMID:22003238

  11. Vegetation change impacts on soil organic carbon chemical composition in subtropical forests

    NASA Astrophysics Data System (ADS)

    Guo, Xiaoping; Meng, Miaojing; Zhang, Jinchi; Chen, Han Y. H.

    2016-07-01

    Changes in the chemical composition of soil organic carbon (SOC) might strongly affect the global carbon cycle as it controls the SOC decomposition rate. Vegetation change associated with long-term land use changes is known to strongly impact the chemical composition of SOC; however, data on the impacts of vegetation change following disturbance events of short durations and succession that occur frequently in forest ecosystems via diverse management objectives on SOC chemical composition are negligible. Here we examined the impacts of vegetation changes on the chemical composition of SOC by sampling soils of native broad-leaved forests, planted mixed broad-leaved and coniferous forests, and tea gardens in eastern China. We used nuclear magnetic resonance spectroscopy to quantify SOC chemical composition. We found that among all components of SOC chemical composition, alkyl carbon (C) and aryl C were more liable to change with vegetation than other SOC components. Soil pH was negatively correlated to the relative abundances of alkyl C and N-alkyl C, and Shannon’s index of overstory plant species was positively correlated to the relative abundances of phenolic C and aromaticity. Our results suggest that vegetation changes following short disturbance events and succession may strongly alter SOC chemical composition in forest ecosystems.

  12. Contamination of vegetables, fruits and soil with geohelmints eggs on organic farms in Poland.

    PubMed

    Kłapeć, Teresa; Borecka, Anna

    2012-01-01

    The objective of this study was to evaluate the contamination of vegetables, fruits and soil with zoonotic parasite eggs on organic and conventional farms in south-eastern Poland. To evaluate the contamination with eggs of zoonotic parasites, examinations were conducted on 8 conventional and 11 organic farms in south-eastern Poland from May-October in 2008 and 2009. The following fruit and vegetables were selected for the experiment: strawberry, leek, onion, carrot, zucchini, beetroot, parsley, potatoes, celery, rhubarb, lettuce, cabbage, broccoli, pumpkin, young beetroot leaves, cauliflower, French beans, turnip, fennel and sorrel. A total of 187 samples of vegetables, fruits and soil were examined by means of a modified flotation method according to Quinn et al. (1980). Contamination with Ascaris, Trichuris and Toxocara eggs was found, with a higher number of positive samples revealed on conventional (34.7%), compared to organic farms (18.9%). The level of contamination in soil samples from conventional farms was higher (88.5% positive samples), than of those from organic farms (32.8%). Of the 15 geohelmints eggs, positive samples were found in vegetables: 9 Toxocara eggs, 4 Ascaris eggs and 2 Trichuris eggs. No geohelmints eggs were observed in the strawberry samples. The consumption of vegetables and fruits contaminated with the eggs of parasites may be the cause of parasitoses in humans. Stricter sanitary standards on farms of all types may limit the incidence of parasitic zoonoses.

  13. Trace metals in soil and vegetables and associated health risk assessment.

    PubMed

    Islam, Md Saiful; Ahmed, Md Kawser; Habibullah-Al-Mamun, Md; Masunaga, Shigeki

    2014-12-01

    The objective of this study was to assess the contamination level of trace metals in soil and vegetables and health risk to the urban population in Bangladesh. The range of Cr, Ni, Cu, As, Cd, and Pb in agricultural soils was 158-1160, 104-443, 157-519, 41-93, 3.9-13, and 84-574 mg/kg, respectively. Sequential extraction tests revealed that the studied metals were predominantly associated with the residual fraction, followed by the organically bound phase. Concerning Cu, Ni, Cd, and Pb in vegetables, more than 50 % samples exceeded the FAO/WHO recommended permissible limits. Considering the transfer of metals from soil to vegetables, Cu and Cd exhibited higher transfer factor (TF) values than the other metals. Target hazard quotient (THQ) for individual metal was below 1, suggesting that people would not experience significant health hazards if they ingest a single metal from vegetables. However, total metal THQ signifies the potential non-carcinogenic health hazard to the highly exposed consumers. The carcinogenic risk (TR) of As (1.9 × 10(-4)) and Pb (2.3 × 10(-5)) through consumption of vegetables were higher than the USEPA threshold level (10(-6)), indicating potential cancer risks.

  14. Vegetation change impacts on soil organic carbon chemical composition in subtropical forests

    PubMed Central

    Guo, Xiaoping; Meng, Miaojing; Zhang, Jinchi; Chen, Han Y. H.

    2016-01-01

    Changes in the chemical composition of soil organic carbon (SOC) might strongly affect the global carbon cycle as it controls the SOC decomposition rate. Vegetation change associated with long-term land use changes is known to strongly impact the chemical composition of SOC; however, data on the impacts of vegetation change following disturbance events of short durations and succession that occur frequently in forest ecosystems via diverse management objectives on SOC chemical composition are negligible. Here we examined the impacts of vegetation changes on the chemical composition of SOC by sampling soils of native broad-leaved forests, planted mixed broad-leaved and coniferous forests, and tea gardens in eastern China. We used nuclear magnetic resonance spectroscopy to quantify SOC chemical composition. We found that among all components of SOC chemical composition, alkyl carbon (C) and aryl C were more liable to change with vegetation than other SOC components. Soil pH was negatively correlated to the relative abundances of alkyl C and N-alkyl C, and Shannon’s index of overstory plant species was positively correlated to the relative abundances of phenolic C and aromaticity. Our results suggest that vegetation changes following short disturbance events and succession may strongly alter SOC chemical composition in forest ecosystems. PMID:27403714

  15. Variations in Soil Salinity and Riparian Vegetation Coverage as Indicators of Stress in an Arid Watershed

    NASA Astrophysics Data System (ADS)

    Gutierrez, M.; Mickus, K.; Johnson, E.

    2003-12-01

    Soil salinity and riparian vegetation coverages of an arid area in northern Mexico through time were investigated. The study area comprises a 10 km segment of the lower Rio Conchos and surrounding undeveloped, non-irrigated land. The amount of area affected by salinity and the type of salinity were determined using EC (electrical conductivity) in conjunction with satellite images and corroborated by field analysis. The soil salinity derived from the remote sensing data was tied to precipitation, greenness of vegetation and water level of a nearby reservoir. The most appropriate method to assess soil salinity was found to be the selective principal component (SPCA) technique of Chavez and Kwarteng while the techniques utilized to discriminate vigorously-growing vegetation were tasseled cap transformation and the normalized difference vegetation index (NDVI). With this region undergoing a severe drought for the last ten years, the response of different parts of the ecosystem and changes in vegetation that so closely affect wildlife and other natural resources in this area can be better evaluated.

  16. Vegetation change impacts on soil organic carbon chemical composition in subtropical forests.

    PubMed

    Guo, Xiaoping; Meng, Miaojing; Zhang, Jinchi; Chen, Han Y H

    2016-07-11

    Changes in the chemical composition of soil organic carbon (SOC) might strongly affect the global carbon cycle as it controls the SOC decomposition rate. Vegetation change associated with long-term land use changes is known to strongly impact the chemical composition of SOC; however, data on the impacts of vegetation change following disturbance events of short durations and succession that occur frequently in forest ecosystems via diverse management objectives on SOC chemical composition are negligible. Here we examined the impacts of vegetation changes on the chemical composition of SOC by sampling soils of native broad-leaved forests, planted mixed broad-leaved and coniferous forests, and tea gardens in eastern China. We used nuclear magnetic resonance spectroscopy to quantify SOC chemical composition. We found that among all components of SOC chemical composition, alkyl carbon (C) and aryl C were more liable to change with vegetation than other SOC components. Soil pH was negatively correlated to the relative abundances of alkyl C and N-alkyl C, and Shannon's index of overstory plant species was positively correlated to the relative abundances of phenolic C and aromaticity. Our results suggest that vegetation changes following short disturbance events and succession may strongly alter SOC chemical composition in forest ecosystems.

  17. GeoInformation studies of soil and vegetation patterns along Climatic Gradients: A Review

    NASA Astrophysics Data System (ADS)

    Shoshany, M.

    2009-04-01

    , spectral reflectance at the visible, NIR and SWIR ranges and emissions in the thermal spectrum. However, despite the magnitude of these projects very few of the methods were proved to be operational yet. The main shortcomings of exiting methods are: - They are highly dependent on accurate calibration which for large region is impractical. - Most of the methods are semi-empirical: case dependent rather than representing robust physical indicators. - There is no one imagery source which is good for all mapping purposes, most of the methods use single imagery source and there is relatively little synergy (fusion) between imagery sources. - Data continuity for long time periods exits mainly for low resolution sources which are limited in supporting modeling of processes. - Difficulties in scaling-up results and methods from the local to the broad-regional scales Within the scope of interest here the most important shortcoming concern the fact that relatively little work treated explicitly regions of high climatic gradient partly due to their high spatio-temporal heterogeneity. Three areas of recent advancements in studying explicitly transition zones between humid and arid regions : - Mapping bio-physical properties of vegetation forms (herbaceous, dwarf-shrubs and shrubs): cover proportions, biomass, primary productivity using synergy between optical (phonologies) and SAR imagery. - Mapping chemical and physical soil properties and estimating their erodibility using hyper and multi spectral methods, and SAR backscattering. - Mapping soil and vegetation patch patterns and their changes within the last decades using historical air-photographs. These advancement s lead to the detection of threshold zones between regions along these gradients according to following indicators: - Life-forms compositions, biomass and primary productivity. Analysis of relationships between biomass and rainfall allow differentiation between cases were vegetation compositions and properties which

  18. Dryland ecosystems: the coupled stochastic dynamics of soil water and vegetation and the role of rainfall seasonality.

    PubMed

    Vezzoli, R; De Michele, C; Pavlopoulos, H; Scholes, R J

    2008-05-01

    In drylands the soil water availability is a key factor ruling the architecture of the ecosystem. The soil water reflects the exchanges of water among soil, vegetation, and atmosphere. Here, a dryland ecosystem is investigated through the analysis of the local interactions between soil water and vegetation forced by rainfall having seasonal and stochastic occurrence. The evolution of dryland ecosystems is represented by a system of two differential equations, having two steady states, one vegetated and the other unvegetated. The rainfall forcing is described by a diffusion process with monthly parameters. In each of the two possible steady states, the probability density functions of soil water and vegetation are derived analytically in terms of the rainfall distribution. The results show how the seasonality of rainfall influences the oscillation of the ecosystem between its vegetated steady state during the wet season and its unvegetated steady state during the dry season.

  19. Air sparging in low permeability soils

    SciTech Connect

    Marley, M.C.

    1996-08-01

    Sparging technology is rapidly growing as a preferred, low cost remediation technique of choice at sites across the United States. The technology is considered to be commercially available and relatively mature. However, the maturity is based on the number of applications of the technology as opposed to the degree of understanding of the mechanisms governing the sparging process. Few well documented case studies exist on the long term operation of the technology. Sparging has generally been applied using modified monitoring well designs in uniform, coarse grained soils. The applicability of sparging for the remediation of DNAPLs in low permeability media has not been significantly explored. Models for projecting the performance of sparging systems in either soils condition are generally simplistic but can be used to provide general insight into the effects of significant changes in soil and fluid properties. The most promising sparging approaches for the remediation of DNAPLs in low permeability media are variations or enhancements to the core technology. Recirculatory sparging systems, sparging/biosparging trenches or curtains and heating or induced fracturing techniques appear to be the most promising technology variants for this type of soil. 21 refs., 9 figs.

  20. Soil moisture response to experimentally altered snowmelt timing is mediated by soil, vegetation, and regional climate patterns

    USGS Publications Warehouse

    Conner, Lafe G; Gill, Richard A.; Belnap, Jayne

    2016-01-01

    Soil moisture in seasonally snow-covered environments fluctuates seasonally between wet and dry states. Climate warming is advancing the onset of spring snowmelt and may lengthen the summer-dry state and ultimately cause drier soil conditions. The magnitude of either response may vary across elevation and vegetation types. We situated our study at the lower boundary of persistent snow cover and the upper boundary of subalpine forest with paired treatment blocks in aspen forest and open meadow. In treatments plots, we advanced snowmelt timing by an average of 14 days by adding dust to the snow surface during spring melt. We specifically wanted to know whether early snowmelt would increase the duration of the summer-dry period and cause soils to be drier in the early-snowmelt treatments compared with control plots. We found no difference in the onset of the summer-dry state and no significant differences in soil moisture between treatments. To better understand the reasons soil moisture did not respond to early snowmelt as expected, we examined the mediating influences of soil organic matter, texture, temperature, and the presence or absence of forest. In our study, late-spring precipitation may have moderated the effects of early snowmelt on soil moisture. We conclude that landscape characteristics, including soil, vegetation, and regional weather patterns, may supersede the effects of snowmelt timing in determining growing season soil moisture, and efforts to anticipate the impacts of climate change on seasonally snow-covered ecosystems should take into account these mediating factors. 

  1. Decadal predictability of soil water, vegetation, and wildfire frequency over North America

    NASA Astrophysics Data System (ADS)

    Chikamoto, Yoshimitsu; Timmermann, Axel; Stevenson, Samantha; DiNezio, Pedro; Langford, Sally

    2015-10-01

    The potential decadal predictability of land hydrological and biogeochemical variables in North America is examined using a 900-year-long pre-industrial control simulation, conducted with the NCAR Community Earth System Model (CESM) version 1.0.3. The leading modes of simulated North American precipitation and soil water storage are characterized essentially by qualitatively similar meridional seesaw patterns associated with the activity of the westerly jet. Whereas the corresponding precipitation variability can be described as a white noise stochastic process, power spectra of vertically integrated soil water exhibit significant redness on timescales of years to decades, since the predictability of soil water storage arises mostly from the integration of precipitation variability. As a result, damped persistence hindcasts following a 1st order Markov process are skillful with lead times of up to several years. This potential multi-year skill estimate is consistent with ensemble hindcasts conducted with the CESM for various initial conditions. Our control simulation further suggests that decadal variations in soil water storage also affect vegetation and wildfire occurrences. The long-term potential predictability of soil water variations in combination with the slow regrowth of vegetation after major disruptions leads to enhanced predictability on decadal timescales for vegetation, terrestrial carbon stock, and fire frequency, in particular in the Southern United States (US)/Mexico region. By contrast, the prediction skill of fire frequency in the Northern US is limited to 1 year. Our results demonstrate that skillful decadal predictions of soil water storage, carbon stock, and fire frequency are feasible with proper initialization of soil conditions. Although the potential predictability in our idealized modeling framework would overestimate the real predictability of the coupled climate-land-vegetation system, the decadal climate prediction may become

  2. Benchmarking LSM root-zone soil mositure predictions using satellite-based vegetation indices

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The application of modern land surface models (LSMs) to agricultural drought monitoring is based on the premise that anomalies in LSM root-zone soil moisture estimates can accurately anticipate the subsequent impact of drought on vegetation productivity and health. In addition, the water and energy ...

  3. Precontact vegetation and soil nutrient status in the shadow of Kohala Volcano, Hawaii

    NASA Astrophysics Data System (ADS)

    Chadwick, Oliver A.; Kelly, Eugene F.; Hotchkiss, Sara C.; Vitousek, Peter M.

    2007-09-01

    Humans colonized Hawaii about 1200 years ago and have progressively modified vegetation, particularly in mesic to dry tropical forests. We use δ 13C to evaluate the contribution of C 3 and C 4 plants to deep soil organic matter to reconstruct pre-human contact vegetation patterns along a wet to dry climate transect on Kohala Mountain, Hawaii Island. Precontact vegetation assemblages fall into three distinct zones: a wet C 3 dominated closed canopy forest where annual rainfall is > 2000 mm, a dry C 4 dominated grassland with annual rainfall < 500 mm, and a broad transition zone between these communities characterized by either C 3 trees with higher water-use efficiency than the rainforest trees or C 3 trees with a small amount of C 4 grasses intermixed. The likelihood of C 4 grass understory decreases with increasing rainfall. We show that the total concentration of rock-derived nutrients in the < 2-mm soil fraction differs in each of these vegetation zones. Nutrient losses are driven by leaching at high rainfall and by plant cycling and wind erosion at low rainfall. By contrast, nutrients are best preserved in surface soils of the intermediate rainfall zone, where rainfall supports abundant plant growth but does not contribute large amounts of water in excess of evapotranspiration. Polynesian farmers exploited these naturally enriched soils as they intensified their upland agricultural systems during the last three centuries before European contact.

  4. On the role of patterns in understanding the functioning of soil-vegetation-atmosphere systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this paper, we review the role of patterns to improve our understanding of water, mass and energy exchange processes in soil-vegetation-atmosphere systems. We explore the main mechanisms that lead to the formation of patterns in these systems and discuss different approaches to characterizing and...

  5. Assessing the evolution of soil moisture and vegetation conditions during the 2012 United States flash drought

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study examines the evolution of several model-based and satellite-derived drought metrics sensitive to soil moisture and vegetation conditions during the extreme flash drought event that impacted major agricultural areas across the central U.S. during 2012. Standardized anomalies from the remo...

  6. Soil erosion and runoff in different vegetation patches from semiarid Central Mexico

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vegetation patches in arid and semiarid areas are important in the regulation of surface hydrological processes. Canopy and ground cover in these fertility islands develop a natural cushion against the impact energy of rainfall, and the higher levels of organic matter improve soil physicochemical pr...

  7. Environmental behavior of technetium in soil and vegetation: implications for radiological impact assessment

    SciTech Connect

    Hoffman, F.O.

    1982-04-01

    Significant radiological exposures have been estimated for hypothetical atmospheric releases of Tc-99 from gaseous diffusion facilities when vegetation-to-soil concentration ratios representative of laboratory experiments are substituted for generic default values assumed in current regulatory models. To test the relevancy of these laboratory ratios, field investigations were conducted to obtain measurements of the vegetation-to-soil concentration ratio for Tc-99 in samples collected near operating gaseous diffusion facilities and to observe the dynamic behavior of technetium in soil and vegetation following a single application of a sprayed solution of /sup 95m/TcO/sub 4//sup -/ Comparison of observed field concentration ratios and calculated steady-state concentration ratios with ratios obtained from previous laboratory experiments indicates that concentration ratios obtained from field data are one to two orders of magnitude less than those obtained from the laboratory. Furthermore, a substantial accumulation of technetium in soil and vegetation may not occur over long periods of time, since concentrations of technetium in both environmental media were observed to decrease with time subsequent to initial application of /sup 95m/TcO/sub 4//sup -/.

  8. The influence of vegetation on sedimentation and resuspension of soil particles in small constructed wetlands.

    PubMed

    Braskerud, B C

    2001-01-01

    When initiatives to mitigate soil erosion are insufficient or fail, constructed surface flow wetlands (CWs) could be a final buffer to reduce pollution before reaching recipients. The objective of this study was to determine the influence of CW vegetation on the retention of soil particles from arable land. Retention was measured with water flow-proportional sampling systems in the inlet and outlet, sedimentation traps, and sedimentation plates in four small CWs over a period of 5 yr. The surface area of the CWs was 265 to 900 m2, and the average hydraulic loads were 1.2 to 3.4 m d(-1). Watershed areas were 0.5 to 1.5 km2. Annual soil particle retention was 30 to 80% or 14 to 121 kg m(-2). Results show that macrophytes stimulate sediment retention by mitigating resuspension of CW sediment. Five years after construction, resuspension had decreased approximately 40% and was negligible. As vegetation cover increases, the influence of macrophytes on soil particle retention reaches a level where other factors, such as hydraulic load and sediment load, were more important. Macrophytes increased the hydraulic efficiency by reducing short-circuit or preferential flow. However, vegetation did not have any influence on the clay concentration in the sediment. Hence, a possible stimulation of particle flocculation was not detected. Vegetation makes it possible to use the positive effect of a short particle settling distance in shallow ponds by hindering resuspension.

  9. Microbial Communities in Cerrado Soils under Native Vegetation Subjected to Prescribed Fires and Under Pasture

    EPA Science Inventory

    The objective of this work was to evaluate the effects of fire regimes and vegetation cover on the structure and dynamics of soil microbial communities, through phospholipid fatty acid (PLFA) analysis. Comparisons were made between native areas with different woody covers ("cerra...

  10. [Soil organic carbon storage changes with land reclamation under vegetation reconstruction on opencast coal mine dump].

    PubMed

    Li, Jun-Chao; Dang, Ting-Hui; Guo, Sheng-Li; Xue, Jiang; Tang, Jun

    2014-10-01

    Vegetation reconstruction was an effective solution to reclaim the opencast coal mine dump which was formed in the process of mining. To understand the impact of the vegetation reconstruction patterns' on the mine soil organic carbon (SOC) storage was essential for selecting the methods of vegetation restoration and also important for accurately estimating the potential of the soil carbon sequestration. The study area was on the Heidaigou opencast coal mine, which was 15 years reclaimed coal mine dump in Zhungeer, Inner Mongolia autonomous region, we selected 5 vegetation reconstruction patterns (natural recovery land, grassland, bush land, mixed woodland of arbor and bush, arbor land), and 16 vegetation types, 408 soil samples (0-100 m), to study the effect of the vegetation reconstruction patterns on the SOC storage. The results were showed as follows: (1) on the reclaimed coal mine dump, the vegetation reconstruction patterns significantly affected the SOC content and its distribution in the soil profile (P < 0.05). The surface 0-10 cm SOC content was grassland > shrub land > arbor forest > mixed forest of arbor and shrub > natural recovery land, in which the grassland, shrub land and arbor forest were about 2.2, 1.3, and 1.3 times of natural recovery land (2.14 g · kg(-1)) respectively. The total nitrogen (TN) showed the similar trends. (2) Among the vegetation types, Medicago sativa had the highest surface SOC content (5.71 g · kg(-1)) and TN content (0.49 g · kg(-1)), that were 171.3% and 166.7% higher than the natural recovery land, and two times of Hippophae rhamnoides, Amorpha fruticosa + Pinus tabulaeformis and Robinia pseudoacacia. (3) The effect of vegetation types on SOC mainly concentrated in the 0-20 cm depth, and the effect on TN accounted for 40 cm. (4) For the SOC storage, the order was original landform area > reclaimed dump > new dump and grassland > woodland (including arbor and shrub land). After 15 years revegetation, the soil carbon

  11. Reflectance of vegetation, soil, and water. [Hidalgo County, Texas

    NASA Technical Reports Server (NTRS)

    Wiegand, C. L. (Principal Investigator)

    1974-01-01

    The author has identified the following significant results. The majority of the rangelands of Hidalgo County, Texas are used in cow-calf operations. Continuous year-long grazing is practiced on about 60% of the acreage and some type of deferred system on the rest. Mechanical brush control is used more than chemical control. Ground surveys gave representative estimates for 15 vegetable crops produced in Hidalgo County. ERTS-1 data were used to estimate the acreage of citrus in the county. Combined Kubleka Munk and regression models, that included a term for shadow areas, gave a higher correlation of composite canopy reflectance with ground truth than either model alone.

  12. Control of aromatic waste air streams by soil bioreactors

    SciTech Connect

    Miller, D.E. ); Canter, L.W. )

    1991-11-01

    Three soils were examined for the ability to degrade hydrocarbon vapors of benzene, toluene, ethylbenzene, and o-xylene (BTEX). Each of these compounds are major aromatic constituents of gasolines. The soils examined were Rubicon Sand from Traverse City, Michigan, Durant Loam from Ada, Oklahoma, and Dougherty Sand from Stratford, Oklahoma. Soil columns were used to examine the effects of soil type, air flow rate and inlet vapor concentrations. Adjustment of the hydrocarbon loading rate produced removals which corresponded to first-order removal kinetics. Estimated residence times of 10 to 20 minutes produced removals of the individual inlet BTEX compounds which ranged from 8 to 39%. Increasing the residence time produced increased removals corresponding to first-order removal rates. Further increases in the residence time revealed transport limitations which restricted additional removals. Soil which had moisture less than 50% of saturation displayed preferential utilization of benzene followed in order by ethylbenzene, toluene, and o-xylene.

  13. Contributions of Understory and/or Overstory Vegetations to Soil Microbial PLFA and Nematode Diversities in Eucalyptus Monocultures

    PubMed Central

    Liu, Zhanfeng; Zhou, Lixia; Fu, Shenglei

    2014-01-01

    Ecological interactions between aboveground and belowground biodiversity have received many attentions in the recent decades. Although soil biodiversity declined with the decrease of plant diversity, many previous studies found plant species identities were more important than plant diversity in controlling soil biodiversity. This study focused on the responses of soil biodiversity to the altering of plant functional groups, namely overstory and understory vegetations, rather than plant diversity gradient. We conducted an experiment by removing overstory and/or understory vegetation to compare their effects on soil microbial phospholipid fatty acid (PLFA) and nematode diversities in eucalyptus monocultures. Our results indicated that both overstory and understory vegetations could affect soil microbial PLFA and nematode diversities, which manifested as the decrease in Shannon–Wiener diversity index (H′) and Pielou evenness index (J) and the increase in Simpson dominance index (λ) after vegetation removal. Soil microclimate change explained part of variance of soil biodiversity indices. Both overstory and understory vegetations positively correlated with soil microbial PLFA and nematode diversities. In addition, the alteration of soil biodiversity might be due to a mixing effect of bottom-up control and soil microclimate change after vegetation removal in the studied plantations. Given the studied ecosystem is common in humid subtropical and tropical region of the world, our findings might have great potential to extrapolate to large scales and could be conducive to ecosystem management and service. PMID:24427315

  14. The role of vegetation in mitigating air quality impacts from traffic emissions--journal

    EPA Science Inventory

    On Apri1 27-28, 2019, a multi-disciplinary group of researchers and po1icymakers met to discuss the state-of-the-science regarding the potential of roadside vegetation to mitigate near-road air quality impacts. Concerns over population exposures to traffic-generated pollutants ne...

  15. Roadside vegetation barrier designs to mitigate near-road air pollution impacts

    EPA Science Inventory

    With increasing evidence that exposures to air pollution near large roadways increases risks of a number of adverse human health effects, identifying methods to reduce these exposures has become a public health priority. Roadside vegetation barriers have shown the potential to re...

  16. Estimating Sahelian and East African soil moisture using the Normalized Difference Vegetation Index

    NASA Astrophysics Data System (ADS)

    McNally, A.; Funk, C.; Husak, G. J.; Michaelsen, J.; Cappelaere, B.; Demarty, J.; Pellarin, T.; Young, T. P.; Caylor, K. K.; Riginos, C.; Veblen, K. E.

    2013-06-01

    Rainfall gauge networks in Sub-Saharan Africa are inadequate for assessing Sahelian agricultural drought, hence satellite-based estimates of precipitation and vegetation indices such as the Normalized Difference Vegetation Index (NDVI) provide the main source of information for early warning systems. While it is common practice to translate precipitation into estimates of soil moisture, it is difficult to quantitatively compare precipitation and soil moisture estimates with variations in NDVI. In the context of agricultural drought early warning, this study quantitatively compares rainfall, soil moisture and NDVI using a simple statistical model to translate NDVI values into estimates of soil moisture. The model was calibrated using in-situ soil moisture observations from southwest Niger, and then used to estimate root zone soil moisture across the African Sahel from 2001-2012. We then used these NDVI-soil moisture estimates (NSM) to quantify agricultural drought, and compared our results with a precipitation-based estimate of soil moisture (the Antecedent Precipitation Index, API), calibrated to the same in-situ soil moisture observations. We also used in-situ soil moisture observations in Mali and Kenya to assess performance in other water-limited locations in sub Saharan Africa. The separate estimates of soil moisture were highly correlated across the semi-arid, West and Central African Sahel, where annual rainfall exhibits a uni-modal regime. We also found that seasonal API and NDVI-soil moisture showed high rank correlation with a crop water balance model, capturing known agricultural drought years in Niger, indicating that this new estimate of soil moisture can contribute to operational drought monitoring. In-situ soil moisture observations from Kenya highlighted how the rainfall-driven API needs to be recalibrated in locations with multiple rainy seasons (e.g., Ethiopia, Kenya, and Somalia). Our soil moisture estimates from NDVI, on the other hand, performed

  17. [Effects of fertilization on the P accumulation and leaching in vegetable greenhouse soil].

    PubMed

    Zhao, Ya-jie; Zhao, Mu-qiu; Lu, Cai-yan; Shi, Yi; Chen, Xin

    2015-02-01

    A packed soil column experiment was conducted to investigate the effect of different fertilization practices on phosphorus (P) accumulation and leaching potential in a vegetable greenhouse soil with different fertility levels. The results showed that the leaching loss of total P in the leachates elevated with the increment of leaching time while the accumulative leaching loss of total P was relatively low, indicating P was mainly accumulated in the soil instead of in the leachate. At the end of the leaching experiment, soil fertility and fertilization treatment affected the content of total phosphorus and Olsen-P significantly. Compared with the low-level-fertility soil, the contents of total P and Olsen-P increased by 14.3% and 12.2% in the medium-level-fertility soil, 33.3% and 37.7% in the high-level-fertility soil. Total P in the combined application of poultry manure and chemical fertilizer (M+NPK) was elevated by 5.7% and 4.3%, compared with the NPK and M treatment. Compared with NPK treatment, Olsen-P in M and M + NPK treatments augmented by 13.0% and 3.1%, respectively. Soil total P and Olsen-P mainly accumulated in the 0-10 cm and 10-20 cm soil layers, and much less in the 20-40 cm soil layer.

  18. Comparative statistical analysis of chrome and vegetable tanning effluents and their effects on related soil.

    PubMed

    Tariq, Saadia R; Shah, Munir H; Shaheen, Nazia

    2009-09-30

    Two tanning units of Pakistan, namely, Kasur and Mian Channun were investigated with respect to the tanning processes (chrome and vegetable, respectively) and the effects of the tanning agents on the quality of soil in vicinity of tanneries were evaluated. The effluent and soil samples from 16 tanneries each of Kasur and Mian Channun were collected. The levels of selected metals (Na, K, Ca, Mg, Fe, Cr, Mn, Co, Cd, Ni, Pb and Zn) were determined by using flame atomic absorption spectrophotometer under optimum analytical conditions. The data thus obtained were subjected to univariate and multivariate statistical analyses. Most of the metals exhibited considerably higher concentrations in the effluents and soils of Kasur compared with those of Mian Channun. It was observed that the soil of Kasur was highly contaminated by Na, K, Ca and Mg emanating from various processes of leather manufacture. Furthermore, the levels of Cr were also present at much enhanced levels than its background concentration due to the adoption of chrome tanning. The levels of Cr determined in soil samples collected from the vicinity of Mian Channun tanneries were almost comparable to the background levels. The soil of this city was found to have contaminated only by the metals originating from pre-tanning processes. The apportionment of selected metals in the effluent and soil samples was determined by a multivariate cluster analysis, which revealed significant differences in chrome and vegetable tanning processes.

  19. Scaling relationships for soil formation and edaphic controls on vegetation growth

    NASA Astrophysics Data System (ADS)

    Hunt, A. G.; Ghanbarian, B.

    2015-12-01

    Critical path analysis (CPA) is suited to calculating the hydraulic conductivity, K, of heterogeneous porous media by quantifying of paths of least resistance. Whenever CPA could be used to calculate K, advective transport scaling relationships from percolation theory should describe solute transport. Two solute transport relationships are applied to predict soil development and edaphic constraints on natural vegetation growth. These results use known exponents from percolation theory and known subsurface flow velocities. The typical flow velocity itself constrains optimal growth rates of cultivars. The percolation scaling relationship constraining vegetation growth is shown to be in accord with data over time scales from hours to 100,000 years, including over a dozen studies (and two models) of tree growth. The scaling function for soil development explains time scales for formation of soils from years to hundreds of millions of years. Data on soil development comes from 23 different studies. The key unification is the common origin of the time and space coordinates for all three relationships in the time of transport through a single pore of roughly micron size at a typical subsurface pore-scale flow velocity. The distinction in evolving time scales is primarily a result of the hierarchical nature of vascular plant root systems, which speed up nutrient access relative to physical transport rates in the soil. The results help explain reduction in forest productivity with age, diminishing soil production with time, and the temporal distinction between the relevance of chemical and biological processes in soils to the global carbon cycle.

  20. Quantification of the uncertainties in soil and vegetation parameterizations for regional climate predictions

    NASA Astrophysics Data System (ADS)

    Breil, Marcus; Schädler, Gerd

    2016-04-01

    The aim of the german research program MiKlip II is the development of an operational climate prediction system that can provide reliable forecasts on a decadal time scale. Thereby, one goal of MiKlip II is to investigate the feasibility of regional climate predictions. Results of recent studies indicate that the regional climate is significantly affected by the interactions between the soil, the vegetation and the atmosphere. Thus, within the framework of MiKlip II a workpackage was established to assess the impact of these interactions on the regional decadal climate predictability. In a Regional Climate Model (RCM) the soil-vegetation-atmosphere interactions are represented in a Land Surface Model (LSM). Thereby, the LSM describes the current state of the land surface by calculating the soil temperature, the soil water content and the turbulent heat fluxes, serving the RCM as lower boundary condition. To be able to solve the corresponding equations, soil and vegetation processes are parameterized within the LSM. Such parameterizations are mainly derived from observations. But in most cases observations are temporally and spatially limited and consequently not able to represent the diversity of nature completely. Thus, soil and vegetation parameterizations always exhibit a certain degree of uncertainty. In the presented study, the uncertainties within a LSM are assessed by stochastic variations of the relevant parameterizations in VEG3D, a LSM developed at the Karlsruhe Institute of Technology (KIT). In a first step, stand-alone simulations of VEG3D are realized with varying soil and vegetation parameters, to identify sensitive model parameters. In a second step, VEG3D is coupled to the RCM COSMO-CLM. With this new model system regional decadal hindcast simulations, driven by global simulations of the Max-Planck-Institute for Meteorology Earth System Model (MPI-ESM), are performed for the CORDEX-EU domain in a resolution of 0.22°. The identified sensitive model

  1. Stable isotopic compositions of carbon in vegetation and soil organic matter along the bioclimatic transect, North Caucasus

    NASA Astrophysics Data System (ADS)

    Kovda, Irina; Morgun, Evgeny; Golubeva, Natalia

    2010-05-01

    Stable isotopic composition of carbon in plant species and soil organic matter was investigated along the bioclimatic transect in the North Caucasus. The aim of this research was to find the possible shift of stable isotopic composition of carbon reflecting the gradual successive changes of landscapes connected with the changes of climatic conditions (temperature, precipitation, air humidity) at a various absolute heights above sea level i.e. along the vertical zonation. The study site was located in the North Caucasus near Arkhiz, Big Zelentchuk valley (43o33-40'N; 41o16-27'E). Soil and vegetation samples were collected along Precaucasus and Caucasus slopes at an absolute heights interval of 1280 - 2065 m. Soils are formed at eluvo-deluvium of noncarbonated silicate massive rocks under warm temperate climate with MAT 4-5oC and MAP ~ 860 mm and more. Samples of vegetation (whole grasses and tree leaves) represented several altitudinal vegetation belts including forest and subalpine belts with coniferous (pine, spruce, fir), mixed coniferous-deciduous (fir + beech), broad-leaved (beech, maple), small-leaved (birch, aspen) forests, elfin birch wood and subalpine meadows. Stable isotope composition of carbon was determined using IRMS Finnigan Delta V+. Stable isotopic composition of vegetal species ranges from -33.04 to -27.29 o/oo with the general trend of lighter δ13С with the decreasing of absolute heights. The most heavier δ13С = ~ -27o/oo were found in subalpine meadow plants, while at a smaller altitudes in the forest belt δ13С shifts to ~ 30-31, and up to ~ - 32-33o/oo. More clear regularities were found for vegetation specimens grouped into three categories such as "trees", "grasses" and "litter". δ13С of each category clearly shifts to the lighter values with the decrease of absolute heights i.e from subalpine meadows to spruce-broad-leaved forests. δ13С shift is about 2,49o/oo for trees, 1,75-4,92 o/oo for grasses and ~ 1,8 o/oo for the litter. The

  2. Laboratory and Airborne BRDF Analysis of Vegetation Leaves and Soil Samples

    NASA Technical Reports Server (NTRS)

    Georgiev, Georgi T.; Gatebe, Charles K.; Butler, James J.; King, Michael D.

    2008-01-01

    Laboratory-based Bidirectional Reflectance Distribution Function (BRDF) analysis of vegetation leaves, soil, and leaf litter samples is presented. The leaf litter and soil samples, numbered 1 and 2, were obtained from a site located in the savanna biome of South Africa (Skukuza: 25.0degS, 31.5degE). A third soil sample, number 3, was obtained from Etosha Pan, Namibia (19.20degS, 15.93degE, alt. 1100 m). In addition, BRDF of local fresh and dry leaves from tulip tree (Liriodendron tulipifera) and acacia tree (Acacia greggii) were studied. It is shown how the BRDF depends on the incident and scatter angles, sample size (i.e. crushed versus whole leaf,) soil samples fraction size, sample status (i.e. fresh versus dry leaves), vegetation species (poplar versus acacia), and vegetation s biochemical composition. As a demonstration of the application of the results of this study, airborne BRDF measurements acquired with NASA's Cloud Absorption Radiometer (CAR) over the same general site where the soil and leaf litter samples were obtained are compared to the laboratory results. Good agreement between laboratory and airborne measured BRDF is reported.

  3. Probabilistic characterization of base flows in river basins: Roles of soil, vegetation, and geomorphology

    NASA Astrophysics Data System (ADS)

    Botter, G.; Porporato, A.; Daly, E.; Rodriguez-Iturbe, I.; Rinaldo, A.

    2007-06-01

    In this paper we extend previous mathematical results on the probabilistic modeling of base flows driven by spatial and temporal fluctuations of soil moisture and affected by intermittent rainfall forcings and by heterogeneous transport, soil, and vegetation properties. Rainfall is modeled as a zero-dimensional marked Poisson process with exponentially distributed intensity, and various descriptors of spatial heterogeneity are used. The master equation for the probability distribution (pdf) of the base flow (here epitomized by the mean daily flow rate in suitably sized catchments) and its moment-generating function are derived by coupling soil moisture balances with a traveltime formulation of transport. Exact solutions for the flow moments are derived in the following cases: (1) two tributary areas in parallel, (2) the rigorous extension to N subbasins, and (3) a simplified geomorphic arrangement of subbasins. Base flow statistics obtained by naive spatial averages of heterogeneous properties exhibit the same mean of the exact solution but may significantly overestimate higher-order moments. Relatively wet climate conditions seem to enhance the effects of the heterogeneity of soil, vegetation, transport, and geomorphic properties, particularly for low-stage flow regimes. The probabilistic structure of the base flow is explicitly linked to relevant climatic and geomorphologic features in addition to the spatial distribution of soil and vegetation properties, with possible ecohydrological implications on long-term water and nutrient mass balances in river basins.

  4. Reclamation history and development intensity determine soil and vegetation characteristics on developed coasts.

    PubMed

    Fang, Shubo; Jia, Xiaobo; Qian, Qingteng; Cui, Jun; Cagle, Grace; Hou, Aixin

    2017-02-20

    The question of where and how to carry out reclamation work in coastal areas is still not well addressed in coastal research. To answer the question, it is essential to quantify the impact of reclamation and the associated ecological and/or environmental responses. In this study, ordinary least square (OLS) analysis and geographical weighted regression (GWR) analysis were performed to identify the reclamation variables that affect soil and vegetation characteristics. Reclamation related variables, including residential population (RP), years of reclamation (YR), income per capita (IP), and land use-based human impact index (HII), were used to explain nitrate, ammonium, total phosphorous, and heavy metals in soil, and the height, density, and above-ground biomass of native hydrophytic vegetation. It was found that variables IP, RP, and HII could be used to explain the height of Scirpus and Phragmites australis as well as above-ground biomass with a R(2) value of no >0.55, and almost all the variables could explain the hydrophytic vegetation characteristics with a higher R(2) value. In comparison to OLS, GWR more reliably reflected the reclamation effects on soil and vegetation characteristics. By GWR analysis, total soil phosphorous, and nitrate and ammonium nitrogen could be explained by RP, YR, and HII, with the highest Ad-R(2) value of 0.496, 0.631 and 0.632, respectively. Both of the GWR and OLS analysis revealed that HII and RP were the better variables for explaining the soil and vegetation characteristics. This work demonstrated that coastal reclamation was highly spatial dependent, which sheds a light on the future development of spatial explicit and process-based models to guide coastal reclamation around the world.

  5. Effect of VOC emissions from vegetation on urban air quality during hot periods

    NASA Astrophysics Data System (ADS)

    Churkina, Galina; Kuik, Friderike; Bonn, Boris; Lauer, Axel; Grote, Ruediger; Butler, Tim

    2016-04-01

    Programs to plant millions of trees in cities around the world aim at the reduction of summer temperatures, increase of carbon storage, storm water control, and recreational space, as well as at poverty alleviation. These urban greening programs, however, do not take into account how closely human and natural systems are coupled in urban areas. Compared with the surroundings of cities, elevated temperatures together with high anthropogenic emissions of air and water pollutants are quite typical in urban systems. Urban and sub-urban vegetation respond to changes in meteorology and air quality and can react to pollutants. Neglecting this coupling may lead to unforeseen negative effects on air quality resulting from urban greening programs. The potential of emissions of volatile organic compounds (VOC) from vegetation combined with anthropogenic emissions of air pollutants to produce ozone has long been recognized. This ozone formation potential increases under rising temperatures. Here we investigate how emissions of VOC from urban vegetation affect corresponding ground-level ozone and PM10 concentrations in summer and especially during heat wave periods. We use the Weather Research and Forecasting Model with coupled atmospheric chemistry (WRF-CHEM) to quantify these feedbacks in the Berlin-Brandenburg region, Germany during the two summers of 2006 (heat wave) and 2014 (reference period). VOC emissions from vegetation are calculated by MEGAN 2.0 coupled online with WRF-CHEM. Our preliminary results indicate that the contribution of VOCs from vegetation to ozone formation may increase by more than twofold during heat wave periods. We highlight the importance of the vegetation for urban areas in the context of a changing climate and discuss potential tradeoffs of urban greening programs.

  6. [Characteristics of N2O emissions from vegetal soils on Fildes peninsula, Antarctica].

    PubMed

    Sun, L; Zhu, R; Xie, Z; Zhao, J; Xing, G; Shi, S; Du, L

    2001-07-01

    The N2O fluxes from the vegetal soils were first measured on the Fildes peninsula, Antarctica, and the total N2O emission was also estimated in the summer 2 months. The daily variations of N2O fluxes appeared single-peak trend under the sunshine or rainy weather conditions but they were irregular under the snow weather conditions and inconsistent with the atmospheric temperatures. The seasonal variations of the N2O fluxes were affected by the temperature and rainfall. The conditions during the transitions between dry and wet seasons improved the N2O emission. The total N2O emissions from moss and lichen soils were 3.7152 kg and 2.5344 kg, respectively. It follows that the vegetal soils are the sources for the atmospheric N2O on the Fildes peninsula, Antarctica.

  7. Concentrations of Radionuclides and Trace Elements in Soils and Vegetation Around the DARHT Facility during 2004

    SciTech Connect

    P.R. Fresquez

    2004-10-01

    Samples of soil, sediment, and unwashed overstory and understory vegetation were collected at four locations around the Dual-Axis Radiographic Hydrodynamic Test (DARHT) facility at Los Alamos National Laboratory (LANL). All samples were analyzed for concentrations of {sup 3}H, {sup 137}Cs, {sup 90}Sr, {sup 238}Pu, {sup 239,240}Pu, {sup 241}Am, {sup 234}U, {sup 235}U, {sup 238}U, Ag, As, Ba, Be, Cd, Cr, Cu, Hg, Ni, Pb, Sb, Se, and Tl. These results, which represent five years since the start of operations, were compared with baseline statistical reference level (BSRL) data established over a four-year-long preoperational period prior to DARHT operations, and to LANL and U.S. Environmental Protection Agency Screening Action Levels (SALs). Most radionuclides and trace elements in soil, sediment, and vegetation were below BSRL values and those soils/sediments that were above BSRLs were far below SALs.

  8. Pollution Status of Pakistan: A Retrospective Review on Heavy Metal Contamination of Water, Soil, and Vegetables

    PubMed Central

    Arshad, Jahanzaib; Iqbal, Farhat; Sajjad, Ashif; Mehmood, Zahid

    2014-01-01

    Trace heavy metals, such as arsenic, cadmium, lead, chromium, nickel, and mercury, are important environmental pollutants, particularly in areas with high anthropogenic pressure. In addition to these metals, copper, manganese, iron, and zinc are also important trace micronutrients. The presence of trace heavy metals in the atmosphere, soil, and water can cause serious problems to all organisms, and the ubiquitous bioavailability of these heavy metal can result in bioaccumulation in the food chain which especially can be highly dangerous to human health. This study reviews the heavy metal contamination in several areas of Pakistan over the past few years, particularly to assess the heavy metal contamination in water (ground water, surface water, and waste water), soil, sediments, particulate matter, and vegetables. The listed contaminations affect the drinking water quality, ecological environment, and food chain. Moreover, the toxicity induced by contaminated water, soil, and vegetables poses serious threat to human health. PMID:25276818

  9. Pollution status of Pakistan: a retrospective review on heavy metal contamination of water, soil, and vegetables.

    PubMed

    Waseem, Amir; Arshad, Jahanzaib; Iqbal, Farhat; Sajjad, Ashif; Mehmood, Zahid; Murtaza, Ghulam

    2014-01-01

    Trace heavy metals, such as arsenic, cadmium, lead, chromium, nickel, and mercury, are important environmental pollutants, particularly in areas with high anthropogenic pressure. In addition to these metals, copper, manganese, iron, and zinc are also important trace micronutrients. The presence of trace heavy metals in the atmosphere, soil, and water can cause serious problems to all organisms, and the ubiquitous bioavailability of these heavy metal can result in bioaccumulation in the food chain which especially can be highly dangerous to human health. This study reviews the heavy metal contamination in several areas of Pakistan over the past few years, particularly to assess the heavy metal contamination in water (ground water, surface water, and waste water), soil, sediments, particulate matter, and vegetables. The listed contaminations affect the drinking water quality, ecological environment, and food chain. Moreover, the toxicity induced by contaminated water, soil, and vegetables poses serious threat to human health.

  10. Phosphorus saturation and mobilization in two typical Chinese greenhouse vegetable soils.

    PubMed

    Kalkhajeh, Yusef Kianpoor; Huang, Biao; Hu, Wenyou; Holm, Peter E; Bruun Hansen, Hans Christian

    2017-04-01

    Chinese greenhouse vegetable production can cause eutrophication of fresh waters due to heavy use of fertilizers. To address this, phosphorus (P) leaching was compared between two major greenhouse vegetable soils from Jiangsu Province, Southeast China: clayey and acid-neutral Guli Orthic Anthrosols and sandy and alkaline Tongshan Ustic Cambosols. A total of 20 intact soil columns were collected based on differences in total P content varying between 1360 and 11,220 mg kg(-1). Overall, six leaching experiments were carried out with collection of leachates over 24 h. Very high P concentrations, with a mean of 3.43 mg L(-1), were found in the leachates from P rich Tongshan soils. In contrast, P leaching from fine-textured but less P rich Guli soils rarely exceeded the suggested environmental P threshold of 0.1 mg L(-1). Strong linear correlations were found between different soil test P measures (STPs) or degree of P saturations (DPSs) and dissolved reactive P (DRP) for Tongshan soil columns. The correlations with Olsen P (r(2) = 0.91) and DPS based on MehlichIII extractable calcium (DPSM3-Ca) (r(2) = 0.87) were the most promising. An Olsen P value above 41 mg kg(-1) or a DPSM3-Ca above 3.44% led to DRP leaching exceeding 0.1 mg L(-1). Accordingly, more than 80% of Tongshan soils resulted in DRP leaching exceeding the environmental P threshold. In conclusion P rich alkaline sandy soils used for greenhouse vegetable production are at high risk of P mobilization across China.

  11. Growing up green on serpentine soils: Biogeochemistry of serpentine vegetation in the Central Coast Range of California

    USGS Publications Warehouse

    Oze, C.; Skinner, C.; Schroth, A.W.; Coleman, R.G.

    2008-01-01

    Serpentine soils derived from the weathering of ultramafic rocks and their metamorphic derivatives (serpentinites) are chemically prohibitive for vegetative growth. Evaluating how serpentine vegetation is able to persist under these chemical conditions is difficult to ascertain due to the numerous factors (climate, relief, time, water availability, etc.) controlling and affecting plant growth. Here, the uptake, incorporation, and distribution of a wide variety of elements into the biomass of serpentine vegetation has been investigated relative to vegetation growing on an adjacent chert-derived soil. Soil pH, electrical conductivity, organic C, total N, soil extractable elements, total soil elemental compositions and plant digestions in conjunction with spider diagrams are utilized to determine the chemical relationships of these soil and plant systems. Plant available Mg and Ca in serpentine soils exceed values assessed in chert soils. Magnesium is nearly 3 times more abundant than Ca in the serpentine soils; however, the serpentine soils are not Ca deficient with Ca concentrations as high as 2235 mg kg-1. Calcium to Mg ratios (Ca:Mg) in both serpentine and chert vegetation are greater than one in both below and above ground tissues. Soil and plant chemistry analyses support that Ca is not a limiting factor for plant growth and that serpentine vegetation is actively moderating Mg uptake as well as tolerating elevated concentrations of bioavailable Mg. Additionally, results demonstrate that serpentine vegetation suppresses the uptake of Fe, Cr, Ni, Mn and Co into its biomass. The suppressed uptake of these metals mainly occurs in the plants' roots as evident by the comparatively lower metal concentrations present in above ground tissues (twigs, leaves and shoots). This research supports earlier studies that have suggested that ion uptake discrimination and ion suppression in the roots are major mechanisms for serpentine vegetation to tolerate the chemistry of

  12. External exposure to radionuclides in air, water, and soil

    SciTech Connect

    Eckerman, K.F.; Ryman, J.C.

    1996-05-01

    Federal Guidance Report No. 12 tabulates dose coefficients for external exposure to photons and electrons emitted by radionuclides distributed in air, water, and soil. The dose coefficients are intended for use by Federal Agencies in calculating the dose equivalent to organs and tissues of the body.

  13. Effectiveness of Vegetation Index Transformation for Land Use Identifying and Mapping in the Area of Oil palm Plantation based on SPOT-6 Imagery (Case Study: PT.Tunggal Perkasa Plantations, Air Molek, Indragiri Hulu)

    NASA Astrophysics Data System (ADS)

    Setyowati, H. A.; S, S. H. Murti B.; Sukentyas, E. S.

    2016-11-01

    The reflection of land surface, atmosphere and vegetation conditions affect the reflectance value of the object is recorded on remote sensing image so that it can affect the outcome of information extraction from remote sensing imagery one multispectral classification. This study aims to assess the ability of the transformation of generic vegetation index (Wide Dynamic Range Vegetation Index), the vegetation index transformation that is capable reducing the influence of the atmosphere (Atmospherically Resistant Vegetation Index), and the transformation of vegetation index that is capable of reducing the influence of the background soil (Second Modified Soil Adjusted Vegetation Index) for the identification and mapping of land use in the oil palm plantation area based on SPOT-6 archived on June 13, 2013 from LAPAN. The study area selected oil palm plantations PT. Tunggal Perkasa Plantations, Air Molek, Indragiri Hulu, Riau Province. The method is using the transformation of the vegetation index ARVI, MSAVI2, and WDRVI. Sample selection method used was stratified random sampling. The test method used mapping accuracy of the confusion matrix. The results showed that the best transformation of the vegetation index for the identification and mapping of land use in the plantation area is ARVI transformation with a total of accuracy is 96%. Accuracy of mapping land use settlements 100%, replanting 82.35%, 81.25% young oil palm, old oil palm 99.46%, 100% bush, body of water 100%, and 100% bare-soil.

  14. Tri-Variate Relationships among Vegetation, Soil, and Topography along Gradients of Fluvial Biogeomorphic Succession.

    PubMed

    Kim, Daehyun; Kupfer, John A

    2016-01-01

    This research investigated how the strength of vegetation-soil-topography couplings varied along a gradient of biogeomorphic succession in two distinct fluvial systems: a forested river floodplain and a coastal salt marsh creek. The strength of couplings was quantified as tri-variance, which was calculated by correlating three singular axes, one each extracted using three-block partial least squares from vegetation, soil, and topography data blocks. Within each system, tri-variance was examined at low-, mid-, and high-elevation sites, which represented early-, intermediate-, and late-successional phases, respectively, and corresponded to differences in ongoing disturbance frequency and intensity. Both systems exhibited clearly increasing tri-variance from the early- to late-successional stages. The lowest-lying sites underwent frequent and intense hydrogeomorphic forcings that dynamically reworked soil substrates, restructured surface landforms, and controlled the colonization of plant species. Such conditions led vegetation, soil, and topography to show discrete, stochastic, and individualistic behaviors over space and time, resulting in a loose coupling among the three ecosystem components. In the highest-elevation sites, in contrast, disturbances that might disrupt the existing biotic-abiotic relationships were less common. Hence, ecological succession, soil-forming processes, and landform evolution occurred in tight conjunction with one another over a prolonged period, thereby strengthening couplings among them; namely, the three behaved in unity over space and time. We propose that the recurrence interval of physical disturbance is important to-and potentially serves as an indicator of-the intensity and mechanisms of vegetation-soil-topography feedbacks in fluvial biogeomorphic systems.

  15. An integrated probabilistic assessment to analyse stochasticity of soil erosion in different restoration vegetation types

    NASA Astrophysics Data System (ADS)

    Zhou, Ji; Fu, Bojie; Gao, Guangyao; Lü, Yihe; Wang, Shuai

    2017-03-01

    The stochasticity of soil erosion reflects the variability of soil hydrological response to precipitation in a complex environment. Assessing this stochasticity is important for the conservation of soil and water resources; however, the stochasticity of erosion event in restoration vegetation types in water-limited environment has been little investigated. In this study, we constructed an event-driven framework to quantify the stochasticity of runoff and sediment generation in three typical restoration vegetation types (Armeniaca sibirica (T1), Spiraea pubescens (T2) and Artemisia copria (T3)) in closed runoff plots over five rainy seasons in the Loess Plateau of China. The results indicate that, under the same rainfall condition, the average probabilities of runoff and sediment in T1 (3.8 and 1.6 %) and T3 (5.6 and 4.4 %) were lowest and highest, respectively. The binomial and Poisson probabilistic model are two effective ways to simulate the frequency distributions of times of erosion events occurring in all restoration vegetation types. The Bayes model indicated that relatively longer-duration and stronger-intensity rainfall events respectively become the main probabilistic contributors to the stochasticity of an erosion event occurring in T1 and T3. Logistic regression modelling highlighted that the higher-grade rainfall intensity and canopy structure were the two most important factors to respectively improve and restrain the probability of stochastic erosion generation in all restoration vegetation types. The Bayes, binomial, Poisson and logistic regression models constituted an integrated probabilistic assessment to systematically simulate and evaluate soil erosion stochasticity. This should prove to be an innovative and important complement in understanding soil erosion from the stochasticity viewpoint, and also provide an alternative to assess the efficacy of ecological restoration in conserving soil and water resources in a semi-arid environment.

  16. Phthalic acid esters in soils from vegetable greenhouses in Shandong Peninsula, East China.

    PubMed

    Chai, Chao; Cheng, Hongzhen; Ge, Wei; Ma, Dong; Shi, Yanxi

    2014-01-01

    Soils at depths of 0 cm to 10 cm, 10 cm to 20 cm, and 20 cm to 40 cm from 37 vegetable greenhouses in Shandong Peninsula, East China, were collected, and 16 phthalic acid esters (PAEs) were detected using gas chromatography-mass spectrometry (GC-MS). All 16 PAEs could be detected in soils from vegetable greenhouses. The total of 16 PAEs (Σ16PAEs) ranged from 1.939 mg/kg to 35.442 mg/kg, with an average of 6.748 mg/kg. Among four areas, including Qingdao, Weihai, Weifang, and Yantai, the average and maximum concentrations of Σ16PAEs in soils at depths of 0 cm to 10 cm appeared in Weifang, which has a long history of vegetable production and is famous for extensive greenhouse cultivation. Despite the different concentrations of Σ16PAEs, the PAE compositions were comparable. Among the 16 PAEs, di(2-ethylhexyl) phthalate (DEHP), di-n-octyl phthalate (DnOP), di-n-butyl phthalate (DnBP), and diisobutyl phthalate (DiBP) were the most abundant. Compared with the results on agricultural soils in China, soils that are being used or were used for vegetable greenhouses had higher PAE concentrations. Among PAEs, dimethyl phthalate (DMP), diethyl phthalate (DEP) and DnBP exceeded soil allowable concentrations (in US) in more than 90% of the samples, and DnOP in more than 20%. Shandong Peninsula has the highest PAE contents, which suggests that this area is severely contaminated by PAEs.

  17. Integrating Vegetation, Soil and Topography to Assess the Impact of Lateral Flow on Plant Solute Uptake

    NASA Astrophysics Data System (ADS)

    Rebel, K. T.; Riha, S. J.; Stedinger, J. R.

    2005-05-01

    Simulation of solute uptake by vegetation in complex terrain typically fails to account for subsurface lateral movement of solutes. This study uses a spatially explicit plant-soil-water simulation model to investigate whether subsurface lateral flow at the sand-clay interface impacts tritium uptake by mixed forest vegetation. Ten hectares of a mixed pine - laurel oak forest on Coastal Plain soils periodically received irrigation with tritium-enriched water (activity ranged from 5,000 to 20,000 pCi/ml) over a three year time period. To simulate water and tritium fluxes we developed a spatially explicit water balance model. Tritium was completely mixed daily with water in each soil layer. Vertical flow of water was simulated using a capacitance model with lateral flow dependent on head development and the local slope of the impeding clay layer. The model was evaluated by comparing biweekly measurements of tritium activity (measured to 3 meter depth) and soil water content (measured to 2 meter depth) in 18 measurement clusters distributed over the catchment. We evaluated the importance of including subsurface flow in model simulations. Lateral flow was locally important (mean distance tritium traveled laterally was 1.35 m). However, after three years of simulation, the maximum predicted lateral movement of tritium did not exceed 70 meters. On the catchment scale, the average simulated amount of tritium taken up by vegetation was not impacted by lateral flow, but smaller scale spatial variability in tritium uptake increased with the inclusion of lateral flow. Simulated tritium uptake was most sensitive to changes in vegetation cover, and was less sensitive to differences in soil properties (e.g. field capacity, hydraulic conductivity and root distribution). When integrated over the study area, the simulation of solute uptake by a mixed forest in Coastal Pain soils was not sensitive to inclusion of subsurface lateral flow of water.

  18. Rapid assessment of soil and groundwater tritium by vegetation sampling

    SciTech Connect

    Murphy, C.E. Jr.

    1995-09-01

    A rapid and relatively inexpensive technique for defining the extent of groundwater contamination by tritium has been investigated. The technique uses existing vegetation to sample the groundwater. Water taken up by deep rooted trees is collected by enclosing tree branches in clear plastic bags. Water evaporated from the leaves condenses on the inner surface of the bag. The water is removed from the bag with a syringe. The bags can be sampled many times. Tritium in the water is detected by liquid scintillation counting. The water collected in the bags has no color and counts as well as distilled water reference samples. The technique was used in an area of known tritium contamination and proved to be useful in defining the extent of tritium contamination.

  19. Effects of Air Drying on Soil Available Phosphorus in Two Grassland Soils

    NASA Astrophysics Data System (ADS)

    Schaerer, M.; Frossard, E.; Sinaj, S.

    2003-04-01

    Mobilization of P from the soil to ground and surface water is principally determined by the amount of P in the soil and physico-chemical as well as biological processes determining the available P-pool that is in equilibrium with soil solution. Soil available P is commonly estimated on air dry soil using a variety of methods (extraction with water, dilute acids and bases, anion exchange resin, isotopic exchange or infinite sinks). Recently, attempts have been made to use these measurements to define the potential for transport of P from soil to water by overland flow or subsurface flow. The effect of air drying on soil properties in general, and plant nutrient status in particular, have been subject of a number of studies. The main objective of this paper was to evaluate the effect of air-drying on soil properties and available P. For this experiment, grassland soils were sampled on two study sites located on slopes in the watershed of Lake Greifensee, 25 km south-east of Zurich. Both soils (0-4 cm depth) are rich in P with 1.7 and 1.3 g kg-1 total P at site I and site II, respectively. The concentrations on isotopically exchangeable P within 1 minute (E1min, readily available P) for the same depth were also very high, 58 and 27 mg P kg soil-1 for the site I and II, respectively. In the present study both field moist and air dried soil samples were analyzed for microbial P (Pmic), resin extractable P (P_r), isotopically exchangeable P (E1min) and amorphous Al and Fe (Alox, Feox). Generally, the microbial P in field moist soils reached values up to 120 mg P/kg soil, whereas after drying they decreased by 73% in average for both soils. On the contrary to Pmic, available P estimated by different methods strongly increased after drying of the soil samples. The concentration of phosphate ions in the soil solution c_p, E1min and P_r were 4.2, 2.2 and 2 times higher in dry soils than in field moist soils. The increase in available P shows significant semilogarithmic

  20. Biomarker patterns in present-day vegetation: consistency and variation - A study on plaggen soils

    NASA Astrophysics Data System (ADS)

    Kirkels, Frédérique; Jansen, Boris; Kalbitz, Karsten

    2013-04-01

    Biomarker patterns in present-day vegetation are commonly used as proxies to reconstruct paleo-vegetation composition, land use history and to elucidate carbon cycling. Plaggen soils are formed by diverse vegetational inputs during century-long plaggen (i.e. sod) application associated with plaggen-agriculture on poor soils in north-western Europe. This resulted in remarkably stable organic matter. Plant source identification by biomarkers could provide insight in yet unknown stabilization mechanisms and the fate of organic matter upon ongoing land use change. The current rationale behind biomarker-based source identification is that patterns observed in present-day vegetation are generally representative with little random variation. However, our knowledge on variability and consistency of biomarker patterns is yet scarce. Therefore, to assess the applicability of biomarkers for source identification in plaggen soils, we analyzed published n-alkane and n-alcohol patterns of species and their various parts which contribute(d) input to plaggen soils. We considered shrubs, trees and grass species and evaluated rescaled patterns (i.e. relative abundances in chain-length range C17-36), odd-over-even predominance (OEP) and predominant n-alkanes. In addition, we explicitly looked into potential sources of systematic variation, e.g. spatial variation (climate, site conditions), temporal variation (seasonality, ontogeny) and laboratory methodology (extraction technique: washing/shaking, Soxhlet/ASE, saponification). We found meaningful clustering of n-alkanes C27, C29, C31 and C33, allowing for clear distinction of input by shrubs, trees and grasses to plaggen soils. Combination of these homologues with complete n-alkane patterns (C17-36) and OEP enabled further differentiation, while n-alcohols patterns were less distinct. Current limitation is the lack of extended and diverse quantitative records on biomarker patterns, especially for n-alcohols, non-leaf and belowground

  1. Soil, Water, and Vegetation Conditions in South Texas

    NASA Technical Reports Server (NTRS)

    Wiegand, C. L.; Gausman, H. W.; Leamer, R. W.; Richardson, A. J. (Principal Investigator)

    1976-01-01

    The author has identified the following significant results. Reflectance differences between the dead leaves of six crops (corn, cotton, sorghum, sugar cane, citrus, and avocado) and the respective bare soils where the dead leaves were lying on the ground were determined from laboratory spectrophotometric measurements over the 0.5- to 2.5 micron wavelength interval. The largest differences were in the near infrared waveband 0.75- to 1.35 microns. Leaf area index was predicted from plant height, percent ground cover, and plant population for irrigated and nonirrigated grain sorghum fields for the 1975 growing season.

  2. Bacterial and enchytraeid abundance accelerate soil carbon turnover along a lowland vegetation gradient in interior Alaska

    USGS Publications Warehouse

    Waldrop, M.P.; Harden, Jennifer W.; Turetsky, M.R.; Petersen, D.G.; McGuire, A.D.; Briones, M.J.I.; Churchill, A.C.; Doctor, D.H.; Pruett, L.E.

    2012-01-01

    Boreal wetlands are characterized by a mosaic of plant communities, including forests, shrublands, grasslands, and fens, which are structured largely by changes in topography and water table position. The soil associated with these plant communities contain quantitatively and qualitatively different forms of soil organic matter (SOM) and nutrient availability that drive changes in biogeochemical cycling rates. Therefore different boreal plant communities likely contain different soil biotic communities which in turn affect rates of organic matter decomposition. We examined relationships between plant communities, microbial communities, enchytraeids, and soil C turnover in near-surface soils along a shallow topographic soil moisture and vegetation gradient in interior Alaska. We tested the hypothesis that as soil moisture increases along the gradient, surface soils would become increasingly dominated by bacteria and mesofauna and have more rapid rates of C turnover. We utilized bomb radiocarbon techniques to infer rates of C turnover and the 13C isotopic composition of SOM and respired CO2 to infer the degree of soil humification. Soil phenol oxidase and peroxidase enzyme activities were generally higher in the rich fen compared with the forest and bog birch sites. Results indicated greater C fluxes and more rapid C turnover in the surface soils of the fen sites compared to the wetland forest and shrub sites. Quantitative PCR analyses of soil bacteria and archaea, combined with enchytraeid counts, indicated that surface soils from the lowland fen ecosystems had higher abundances of these microbial and mesofaunal groups. Fungal abundance was highly variable and not significantly different among sites. Microbial data was utilized in a food web model that confirmed that rapidly cycling systems are dominated by bacterial activity and enchytraeid grazing. However, our results also suggest that oxidative enzymes play an important role in the C mineralization process in

  3. Derivation of soil thresholds for lead applying species sensitivity distribution: A case study for root vegetables.

    PubMed

    Ding, Changfeng; Ma, Yibing; Li, Xiaogang; Zhang, Taolin; Wang, Xingxiang

    2016-02-13

    The combination of food quality standard and soil-plant transfer models can be used to derive critical limits of heavy metals for agricultural soils. In this paper, a robust methodology is presented, taking the variations of plant species and cultivars and soil properties into account to derive soil thresholds for lead (Pb) applying species sensitivity distribution (SSD). Three species of root vegetables (four cultivars each for radish, carrot, and potato) were selected to investigate their sensitivity differences for accumulating Pb through greenhouse experiment. Empirical soil-plant transfer model was developed from carrot New Kuroda grown in twenty-one soils covering a wide variation in physicochemical properties and was used to normalize the bioaccumulation data of non-model cultivars. The relationship was then validated to be reliable and would not cause over-protection using data from field experimental sites and published independent studies. The added hazardous concentration for protecting 95% of the cultivars not exceeding the food quality standard (HC5add) were then calculated from the Burr Type III function fitted SSD curves. The derived soil Pb thresholds based on the added risk approach (total soil concentration subtracting the natural background part) were presented as continuous or scenario criteria depending on the combination of soil pH and CEC.

  4. Effectiveness of soil-vegetative covers for waste sites

    SciTech Connect

    Hauser, V.L.; Shaw, M.A.; Weand, B.L.

    1994-12-31

    The authors propose an inexpensive and practical cover for landfills, reclaimed mine land, oil shale residues, fire training areas, and similar sites. This cover stores precipitation in the soil until it is removed by evapotranspiration (ET). The authors call it the ET Cover. The ET Cover contains no impermeable materials, but it requires adequate soil water-holding capacity to store precipitation until ET can remove the water from storage. This evaluation of the ET Cover concept demonstrated that it is appropriate for use in much of the United States west of the 95th meridian (western Missouri). It is not appropriate for use in wet, cool climates such as the northern California coast. The ET Cover controls infiltration effectively under high-precipitation conditions where potential evapotranspiration and surface runoff are high and the growing season is long. The authors evaluated the appropriateness of the ET Cover for each site with a comprehensive computer model that is capable of simulating the variability of climate over periods in excess of 100 years.

  5. Soil, vegetation and total organic carbon stock development in self-restoring abandoned vineyards

    NASA Astrophysics Data System (ADS)

    József Novák, Tibor; Incze, József; Spohn, Marie; Giani, Luise

    2016-04-01

    Abandoned vineyard's soil and vegetation development was studied on Tokaj Nagy-Hill, which is one of the traditional wine-producing regions of Hungary, it is declared as UNESCO World Heritage site as cultural landscape. Spatial distribution and pattern of vineyards were changing during the last several hundreds of years, therefore significant part of abandoned vineyards were subjected to long-term spontaneous secondary succession of vegetation and self-restoration of soils in absence of later cultivation. Two chronosequences of spontaneously regenerating vineyard abandonments, one on south (S-sequence) and one on southwest (SW-sequence) slope with differing times since their abandonment (193, 142, 101, 63, 39 and 14 years), were compiled and studied. The S-sequence was 25-35% sloped and strongly eroded, and the SW-sequence was 17-25% sloped and moderately eroded. The sites were investigated in respect of vegetation characteristics, soil physico-chemical characteristics, total organic carbon stocks (TOC stocks), accumulation rates of total organic carbon (TOC accumulation rates), and soil profiles, which were classified according to the World Reference Base (WRB) 2014. Vegetation development resulted in shrub-grassland mosaics, supplemented frequently by protected forb species and forest development at the earliest abandonment in S-sequence, and predominantly to forest vegetation in SW-sequence, where trees were only absent at the 63 and 14 years old abandonment sites. In all sites soils on level of reference groups according to WRB were classified, and Cambisols, Regosols, Calcisols, Leptosols, Chernozems and Phaeozems were found. Soils of the S-sequence show shallow remnants of loess cover with colluvic and redeposited soil materials containing 15-65% skeletal volcanic rock of weathering products coated by secondary calcium carbonates. The SW-sequence profiles are developed on deep loess or loess derivatives. The calcium-carbonate content was higher in profiles of

  6. Vegetation stress from soil moisture and chlorophyll fluorescence: synergy between SMAP and FLEX approaches

    NASA Astrophysics Data System (ADS)

    Moreno, Jose; Moran, Susan

    2014-05-01

    Vegetation stress detection continues being a focal objective for remote sensing techniques. It has implications not only for practical applications such as irrigation optimization or precision agriculture, but also for global climate models, providing data to better link water and carbon exchanges between the surface and the atmospheric and improved parameterization of the role of terrestrial vegetation in the coupling of water and carbon cycles. Traditional approaches to map vegetation stress using remote sensing techniques have been based on measurements of soil moisture status, canopy (radiometric) temperature and, to a lesser extent, canopy water content, but new techniques such as the dynamics of vegetation fluorescence emission, are also now available. Within the context of the preparatory activities for the SMAP and FLEX missions, a number of initiatives have been put in place to combine modelling activities and field experiments in order to look for alternative and more efficient ways of detecting vegetation stress, with emphasis on synergistic remote sensing approaches. The potential of solar-induced vegetation fluorescence as an early indicator of stress has been widely demonstrated, for different type of stress conditions: light amount (excess illumination) and conditions (direct/diffuse), temperature extremes (low and high), soil water availability (soil moisture), soil nutrients (nitrogen), atmospheric water vapour and atmospheric CO2 concentration. The effects caused by different stress conditions are sometimes difficult to be decoupled, also because different causes are often combined, but in general they then to change the overall fluorescence emission (modulating amplitude) or changing the relative contributions of photosystems PSI and PSII or the relative fluorescence re-absorption effects caused by modifications in the structure of pigment bed responsible for light absorption, in particular for acclimation for persistent stress conditions. While

  7. AirMOSS P-Band Radar Retrieval of Subcanopy Soil Moisture Profile

    NASA Astrophysics Data System (ADS)

    Tabatabaeenejad, A.; Burgin, M. S.; Duan, X.; Moghaddam, M.

    2013-12-01

    Knowledge of soil moisture, as a key variable of the Earth system, plays an important role in our under-standing of the global water, energy, and carbon cycles. The importance of such knowledge has led NASA to fund missions such as Soil Moisture Active and Passive (SMAP) and Airborne Microwave Observatory of Subcanopy and Subsurface (AirMOSS). The AirMOSS mission seeks to improve the estimates of the North American Net Ecosystem Exchange (NEE) by providing high-resolution observations of the root zone soil moisture (RZSM) over regions representative of the major North American biomes. AirMOSS flies a P-band SAR to penetrate vegetation and into the root zone to provide estimates of RZSM. The flights cover areas containing flux tower sites in regions from the boreal forests in Saskatchewan, Canada, to the tropical forests in La Selva, Costa Rica. The radar snapshots are used to generate estimates of RZSM via inversion of a scattering model of vegetation overlying soils with variable moisture profiles. These retrievals will be used to generate a time record of RZSM, which will be integrated with an ecosystem demography model in order to estimate the respiration and photosynthesis carbon fluxes. The aim of this work is the retrieval of the moisture profile over AirMOSS sites using the collected P-band radar data. We have integrated layered-soil scattering models into a forest scattering model; for the backscattering from ground and for the trunk-ground double-bounce mechanism, we have used a layered small perturbation method and a coherent scattering model of layered soil, respectively. To estimate the soil moisture profile, we represent it as a second-order polynomial in the form of az2 + bz + c, where z is the depth and a, b, and c are the coefficients to be retrieved from radar measurements. When retrieved, these coefficients give us the soil moisture up to a prescribed depth of validity. To estimate the unknown coefficients of the polynomial, we use simulated

  8. The Dependence of Peat Soil Hydraulic Conductivity on Dominant Vegetation Type in Mountain Fens

    NASA Astrophysics Data System (ADS)

    Crockett, A. C.; Ronayne, M. J.; Cooper, D. J.

    2014-12-01

    The peat soil within fen wetlands provides water storage that can substantially influence the hydrology of mountain watersheds. In this study, we investigated the relationship between hydraulic conductivity and vegetation type for fens occurring in Rocky Mountain National Park (RMNP), Colorado, USA. Vegetation in RMNP fens can be dominated by woody plants and shrubs, such as willows; by mosses; or by herbaceous plants such as sedges. Fens dominated by each vegetation type were selected for study. Six fens were investigated, all of which are in the Colorado River watershed on the west side of RMNP. For each site, soil hydraulic conductivity was measured at multiple locations using a single-ring infiltrometer. As a result of the shallow water table in these fens (the water table was always within 10 cm of the surface), horizontal hydraulic gradients were produced during the field tests. The measured infiltration rates were analyzed using the numerical model HYDRUS. In order to determine the hydraulic conductivity, a parameter estimation problem was solved using HYDRUS as the forward simulator. Horizontal flow was explicitly accounted for in the model. This approach produced more accurate estimates of hydraulic conductivity than would be obtained using an analytical solution that assumes strictly vertical flow. Significant differences in hydraulic properties between fens appear to result at least in part from the effects of different dominant vegetation types on peat soil formation.

  9. Effects of varying soil moisture contents and vegetation canopies on microwave emissions

    NASA Technical Reports Server (NTRS)

    Burke, H.-H. K.; Schmugge, T. J.

    1982-01-01

    Results of NASA airborne passive microwave scans of bare and vegetated fields for comparison with ground truth tests are discussed and a model for atmospheric scattering of radiation by vegetation is detailed. On-board radiometers obtained data at 21, 2.8, and 1.67 cm during three passes over each of 46 fields, 28 of which were bare and the others having wheat or alfalfa. Ground-based sampling included moisture in five layers down to 15 cm in addition to soil temperature. The relationships among the brightness temperature and soil moisture, as well as the surface roughness and the vegetation canopy were examined. A model was developed for the dielectric coefficient and volume scattering for a vegetation medium. L- to C-band data were found useful for retrieving soil information directly. A surface moisture content of 5-35% yielded an emissivity of 0.9-0.7. The data agreed well with a combined multilayer radiative transfer model with simple roughness correction.

  10. Anaerobic Soil Disinfestation (ASD) Combined with Soil Solarization for Root-Knot Nematode Control in Vegetable and Ornamental Crops in Florida

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Anaerobic soil disinfestation (ASD) combined with soil solarization continues to be evaluated for management of plant-parasitic nematodes in vegetable and ornamental crops in Florida. ASD combines organic amendments and soil saturation to stimulate microbial activity and create anaerobic conditions...

  11. Uptake of explosives from contaminated soil by existing vegetation at the Iowa Army Ammunition Plant

    SciTech Connect

    Schneider, J.F.; Zellmer, S.D.; Tomczyk, N.A.; Rastorier, J.R.; Chen, D.; Banwart, W.L.

    1995-02-01

    This study examines the uptake of explosives by existing vegetation growing in soils contaminated with 2,4,6-trinitrotoluene (TNT) and 1,3,5-trinitro-3,5-triazine (RDX) in three areas at the Iowa Army Ammunition Plant (IAAP). To determine explosives uptake under natural environmental conditions, existing plant materials and soil from the root zone were sampled at different locations in each area, and plant materials were separated by species. Standard methods were used to determine the concentrations of explosives, their derivatives, and metabolites in the soil samples. Plant materials were also analyzed. The compound TNT was not detected in the aboveground portion of plants, and vegetation growing on TNT-contaminated soils is not considered a health hazard. However, soil and plant roots may contain TNT degradation products that may be toxic; hence, their consumption is not advised. The compound RDX was found in the tops and roots of plants growing on RDX-contaminated soils at all surveyed sites. Although RDX is not a listed carcinogen, several of its potentially present degradation products are carcinogens. Therefore, the consumption of any plant tissues growing on RDX-contaminated sites should be considered a potential health hazard.

  12. Tree vegetation and waste amendments to improve the physical condition of copper mine soils.

    PubMed

    Asensio, V; Vega, F A; Andrade, M L; Covelo, E F

    2013-01-01

    Mine soils are often physically degraded, which hinders plants development. The untreated soils at the depleted copper mine in Touro (Galicia, north-west Spain) have no vegetation and are probably physically degraded. These mine soils were reclaimed both by planting trees and amending with waste (sewage sludge and paper mill residues). The purpose was to determine the effect of these treatments on the physical quality of the soils of the Touro mine under field conditions. We evaluated the physical situation of both the settling pond and the mine tailings in Touro, then comparing them with their respective treated areas: vegetated, amended or with both treatments at the same time. We corroborated that the physical degradation of untreated soils was considerable: low porosity, high density and less than 50% of water stable aggregates. The trees that were planted increased porosity, probably due to root activity. The added amendments increased the mean weight diameter (MWD), the percentage of water stable aggregates (WSA) and the stability index (SI) due to the high organic carbon content in the added wastes. We verified that using both treatments at the same time is better than using only one to improve the physical situation of mine soils.

  13. Infectivity of soilborne Frankia and mycorrhizae in Discaria trinervis along a vegetation gradient in Patagonian soil.

    PubMed

    Chaia, Eugenia Esther; Fontenla, Sonia Beatriz; Vobis, Gernot; Wall, Luis Gabriel

    2006-01-01

    The infective capacities of the nitrogen fixing Actinomycete Frankia and arbuscular mycorrhizal fungi from soils near watercourses, along a vegetation gradient, were studied using plant bioassays. Frankia and arbuscular mycorrhizas capable of infecting Discaria trinervis were found at seventeen sites sampled. More specific enumeration of the infective capacities of both microorganisms in relation to environmental factors was performed in seven representative soils of the analysed vegetation zones (rainforest, xeric forest and steppe) using the most probable number method. The highest nodulation capacities ranged from 340 infective units g(-1 )soil, in a steppe marsh devoid of actinorhizas, to 61 in a coastal actinorhizal scrub (in xeric forest). The highest number of infective mycorrhizal units--also found in marsh--was 145. In general, rainforest soils had the lowest values for both microorganisms. Infective units of Frankia and arbuscular mycorrhizal fungi in soil were positively correlated (r = 0.89, P < 0.05). Both soilborne symbionts showed the highest infective capacity in semi-arid conditions nearby watercourse and at the valley bottom location. Tripartite symbiosis was effective in plants inoculated with steppe and xeric forest soils and plants inoculated with Frankia BCU110501 and Glomus mosseae. Interaction between both symbionts and influence of environmental conditions, in general, would contribute to define comparable trends of their infective capacities.

  14. The effects of vegetation cover on soil nematode communities in various biotopes disturbed by industrial emissions.

    PubMed

    Šalamún, Peter; Hanzelová, Vladimíra; Miklisová, Dana; Šestinová, Oľga; Findoráková, Lenka; Kováčik, Peter

    2017-08-15

    Better understanding of interactions among belowground and aboveground components in biotopes may improve our knowledge about soil ecosystem, and is necessary in environment assessment using indigenous soil organisms. In this study, we proposed that in disturbed biotopes, vegetation play important role in the buffering of contamination impact on soil communities and decrease the ecological pressure on soil biota. To assess the effects of these interactions we compared nematode communities, known for their bioindication abilities, from four types of disturbed and undisturbed biotopes (coniferous forest, permanent grassland, agricultural field, clearings), where the main stress agent was represented by long-term acidic industrial emissions containing heavy metals (As, Cd, Cu, and Pb). To understand the ecological interactions taking place in studied biotopes, we studied abiotic factors (soil properties) and biotic factors (vegetation, nematode communities). Except significant increase in metals total and mobile concentrations in disturbed biotopes soil, we found acidification of soil horizon, mainly in the clearings (pH=3.68), due to SO2 precipitation. These factors has caused in clearings degradation of native phytocoenoses and decrease in decomposition rate characterized by high amount of organic matter (Cox=4.29%). Nematodes reacts to these conditions by shifts in trophic structure (bacteriovores to fungal feeders), increase in c-p 2 genera (Aphelenchoides, Acrobeloides, and Cephalobus), absence of sensitive groups (c-p 3-5, omnivores, predators), and decrease in ecological indices (SI, MI, MI2-5, H'). Similar contamination was found in forest biotope, but the nematodes composition indicates more suitable conditions; more complex community structure (presence of sensitive trophic and higher c-p groups), higher abundance and indices values, comparable with less stressed field and grassland biotopes. As showed our results, the vegetation undoubtedly plays an

  15. Estimation of Soil Moisture Content Using Air-Launched GPR Techniques in Variable Soil Conditions

    NASA Astrophysics Data System (ADS)

    Hardel, B.; Kelly, B.

    2008-12-01

    Air-launched Ground Penetrating Radar (GPR) techniques have most frequently been used for infrastructure characterization, but these techniques show promise for soil moisture estimation in the near subsurface. Air- launched GPR data can be acquired very quickly, and data processing can be easily automated, so these techniques have potential for efficient estimation of water content in the shallow subsurface over large areas. In this experiment, we investigate the efficacy of air-launched GPR techniques for estimating soil water content under saturated and dry conditions in both sandy and organic-rich soils. Data were also acquired to investigate the depth of penetration of air-launched data in these soils using multiple GPR frequencies. The experiment was performed in a large tank under controlled climatic conditions. Initially, the tank was filled with wet sand to a depth of 24-cm, and GPR data were acquired over the sand using 250-, 500-, and 1000-MHz antennas. Then, a thin plastic tarp was placed on the wet sand, a 3-cm layer of dry sand was placed on the tarp, and data collection was repeated. Additional 3-cm layers of dry sand were placed in the tank, with data acquisition after each layer, until the dry sand layer was 15-cm thick. The tank was then excavated, and a basal layer of dry sand was added. Data were again acquired over the dry sand, and the incremental filling of the tank and data acquisition were repeated using 3-cm layers of wet sand. Finally, the entire process was repeated using a basal layer of wet organic soil overlain by dry organic soil and using a basal layer of dry organic soil overlain by wet organic soil. For all air-launch data, the dielectric constant was determined using the amplitudes of the reflection from the soil surface, and Topp's equation was used to convert the dielectric constant to water content. Data analysis is ongoing, but preliminary results indicate that water content can be estimated with reasonable accuracy in both

  16. Effect of liming on sulfate transformation and sulfur gas emissions in degraded vegetable soil treated by reductive soil disinfestation.

    PubMed

    Meng, Tianzhu; Zhu, Tongbin; Zhang, Jinbo; Cai, Zucong

    2015-10-01

    Reductive soil disinfestation (RSD), namely amending organic materials and mulching or flooding to create strong reductive status, has been widely applied to improve degraded soils. However, there is little information available about sulfate (SO4(2-)) transformation and sulfur (S) gas emissions during RSD treatment to degraded vegetable soils, in which S is generally accumulated. To investigate the effects of liming on SO4(2-) transformation and S gas emissions, two SO4(2-)-accumulated vegetable soils (denoted as S1 and S2) were treated by RSD, and RSD plus lime, denoted as RSD0 and RSD1, respectively. The results showed that RSD0 treatment reduced soil SO4(2-) by 51% and 61% in S1 and S2, respectively. The disappeared SO4(2-) was mainly transformed into the undissolved form. During RSD treatment, hydrogen sulfide (H2S), carbonyl sulfide (COS), and dimethyl sulfide (DMS) were detected, but the total S gas emission accounted for <0.006% of total S in both soils. Compared to RSD0, lime addition stimulated the conversion of SO4(2-) into undissolved form, reduced soil SO4(2-) by 81% in S1 and 84% in S2 and reduced total S gas emissions by 32% in S1 and 57% in S2, respectively. In addition to H2S, COS and DMS, the emissions of carbon disulfide, methyl mercaptan, and dimethyl disulfide were also detected in RSD1 treatment. The results indicated that RSD was an effective method to remove SO4(2-), liming stimulates the conversion of dissolved SO4(2-) into undissolved form, probably due to the precipitation with calcium.

  17. Effects of ozone-vegetation coupling on surface ozone air quality via biogeochemical and meteorological feedbacks

    NASA Astrophysics Data System (ADS)

    Sadiq, Mehliyar; Tai, Amos P. K.; Lombardozzi, Danica; Martin, Maria Val

    2017-02-01

    Tropospheric ozone is one of the most hazardous air pollutants as it harms both human health and plant productivity. Foliage uptake of ozone via dry deposition damages photosynthesis and causes stomatal closure. These foliage changes could lead to a cascade of biogeochemical and biogeophysical effects that not only modulate the carbon cycle, regional hydrometeorology and climate, but also cause feedbacks onto surface ozone concentration itself. In this study, we implement a semi-empirical parameterization of ozone damage on vegetation in the Community Earth System Model to enable online ozone-vegetation coupling, so that for the first time ecosystem structure and ozone concentration can coevolve in fully coupled land-atmosphere simulations. With ozone-vegetation coupling, present-day surface ozone is simulated to be higher by up to 4-6 ppbv over Europe, North America and China. Reduced dry deposition velocity following ozone damage contributes to ˜ 40-100 % of those increases, constituting a significant positive biogeochemical feedback on ozone air quality. Enhanced biogenic isoprene emission is found to contribute to most of the remaining increases, and is driven mainly by higher vegetation temperature that results from lower transpiration rate. This isoprene-driven pathway represents an indirect, positive meteorological feedback. The reduction in both dry deposition and transpiration is mostly associated with reduced stomatal conductance following ozone damage, whereas the modification of photosynthesis and further changes in ecosystem productivity are found to play a smaller role in contributing to the ozone-vegetation feedbacks. Our results highlight the need to consider two-way ozone-vegetation coupling in Earth system models to derive a more complete understanding and yield more reliable future predictions of ozone air quality.

  18. Development of a deterministic downscaling algorithm for remote sensing soil moisture footprint using soil and vegetation classifications

    NASA Astrophysics Data System (ADS)

    Shin, Yongchul; Mohanty, Binayak P.

    2013-10-01

    Soil moisture (SM) at the local scale is required to account for small-scale spatial heterogeneity of land surface because many hydrological processes manifest at scales ranging from cm to km. Although remote sensing (RS) platforms provide large-scale soil moisture dynamics, scale discrepancy between observation scale (e.g., approximately several kilometers) and modeling scale (e.g., few hundred meters) leads to uncertainties in the performance of land surface hydrologic models. To overcome this drawback, we developed a new deterministic downscaling algorithm (DDA) for estimating fine-scale soil moisture with pixel-based RS soil moisture and evapotranspiration (ET) products using a genetic algorithm. This approach was evaluated under various synthetic and field experiments (Little Washita-LW 13 and 21, Oklahoma) conditions including homogeneous and heterogeneous land surface conditions composed of different soil textures and vegetations. Our algorithm is based on determining effective soil hydraulic properties for different subpixels within a RS pixel and estimating the long-term soil moisture dynamics of individual subpixels using the hydrological model with the extracted soil hydraulic parameters. The soil moisture dynamics of subpixels from synthetic experiments matched well with the observations under heterogeneous land surface condition, although uncertainties (Mean Bias Error, MBE: -0.073 to -0.049) exist. Field experiments have typically more variations due to weather conditions, measurement errors, unknown bottom boundary conditions, and scale discrepancy between remote sensing pixel and model grid resolution. However, the soil moisture estimates of individual subpixels (from the airborne Electronically Scanned Thinned Array Radiometer (ESTAR) footprints of 800 m × 800 m) downscaled by this approach matched well (R: 0.724 to -0.914, MBE: -0.203 to -0.169 for the LW 13; R: 0.343-0.865, MBE: -0.165 to -0.122 for the LW 21) with the in situ local scale soil

  19. Regional accumulation characteristics of cadmium in vegetables: Influencing factors, transfer model and indication of soil threshold content.

    PubMed

    Yang, Yang; Chen, Weiping; Wang, Meie; Peng, Chi

    2016-12-01

    A regional investigation in the Youxian prefecture, southern China, was conducted to analyze the impact of environmental factors including soil properties and irrigation in conjunction with the use of fertilizers on the accumulation of Cd in vegetables. The Cd transfer potential from soil to vegetable was provided by the plant uptake factor (PUF), which varied by three orders of magnitude and was described by a Gaussian distribution model. The soil pH, content of soil organic matter (SOM), concentrations of Zn in the soil, pH of irrigation water and nitrogenous fertilizers contributed significantly to the PUF variations. A path model analysis, however, revealed the principal control of the PUF values resulted from the soil pH, soil Zn concentrations and SOM. Transfer functions were developed using the total soil Cd concentrations, soil pH, and SOM. They explained 56% of the variance for all samples irrespective of the vegetable genotypes. The transfer functions predicted the probability of exceeding China food safety standard concentrations for Cd in four major consumable vegetables under different soil conditions. Poor production practices in the study area involved usage of soil with pH values ≤ 5.5, especially for the cultivation of Raphanus sativus L., even with soil Cd concentrations below the China soil quality standard. We found the soil standard Cd concentrations for cultivating vegetables was not strict enough for strongly acidic (pH ≤ 5.5) and SOM-poor (SOM ≤ 10 g kg(-1)) soils present in southern China. It is thus necessary to address the effect of environmental variables to generate a suitable Cd threshold for cultivated soils.

  20. Accumulation of carbon and nitrogen in vegetation and soils of deglaciated area in Ellesmere Island, high-Arctic Canada

    NASA Astrophysics Data System (ADS)

    Osono, Takashi; Mori, Akira S.; Uchida, Masaki; Kanda, Hiroshi

    2016-09-01

    The amount of biomass, carbon (C), and nitrogen (N) in vegetation and soil were measured at two spatial scales in the high Arctic. At the scale of proglacial landscape, the amount of C and N in aboveground and belowground parts of vegetation, surface litter, and soil were significantly affected by the habitat (moraines vs hummocks), the relative age of the terrain after the deglaciation, and/or the vegetation. At another scale, we focused on mudboils as an agent of local disturbance in the vegetation and soil of the glacier foreland. The biomass and the amount of C and N in aboveground vegetation, surface litter, biological soil crust, and soil were generally increased with the stage of mudboils' inactivation. Biomass, C, and N in aboveground vegetation and surface litter were generally greater at moraine than at hummock, whereas those in biological soil crust and soil were greater at hummock. Principal component analysis identified two pathways, xeric and mesic ones on moraines and hummocks, respectively, of C and N accumulation both at the two spatial scales. These results suggested that the C and N accumulation was not linearly related to the time since deglaciation and that moisture condition, vegetation, and mudboil activity were locally important.

  1. Spatio-temporal evaluation of resolution enhancement for passive microwave soil moisture and vegetation optical depth

    NASA Astrophysics Data System (ADS)

    Gevaert, A. I.; Parinussa, R. M.; Renzullo, L. J.; van Dijk, A. I. J. M.; de Jeu, R. A. M.

    2016-03-01

    Space-borne passive microwave radiometers are used to derive land surface parameters such as surface soil moisture and vegetation optical depth (VOD). However, the value of such products in regional hydrology is limited by their coarse resolution. In this study, the land parameter retrieval model (LPRM) is used to derive enhanced resolution (∼10 km) soil moisture and VOD from advanced microwave scanning radiometer (AMSR-E) brightness temperatures sharpened by a modulation technique based on high-frequency observations. A precipitation mask based on brightness temperatures was applied to remove precipitation artefacts in the sharpened LPRM products. The spatial and temporal patterns in the resulting products are evaluated against field-measured and modeled soil moisture as well as the normalized difference vegetation index (NDVI) over mainland Australia. Results show that resolution enhancement accurately sharpens the boundaries of different vegetation types, lakes and wetlands. Significant changes in temporal agreement between LPRM products and related datasets are limited to specific areas, such as lakes and coastal areas. Spatial correlations, on the other hand, increase over most of Australia. In addition, hydrological signals from irrigation and water bodies that were absent in the low-resolution soil moisture product become clearly visible after resolution enhancement. The increased information detail in the high-resolution LPRM products should benefit hydrological studies at regional scales.

  2. Interacting vegetative and thermal contributions to water movement in desert soil

    USGS Publications Warehouse

    Garcia, C.A.; Andraski, B.J.; Stonestrom, D.A.; Cooper, C.A.; Šimůnek, J.; Wheatcraft, S.W.

    2011-01-01

    Thermally driven water-vapor flow can be an important component of total water movement in bare soil and in deep unsaturated zones, but this process is often neglected when considering the effects of soil–plant–atmosphere interactions on shallow water movement. The objectives of this study were to evaluate the coupled and separate effects of vegetative and thermal-gradient contributions to soil water movement in desert environments. The evaluation was done by comparing a series of simulations with and without vegetation and thermal forcing during a 4.7-yr period (May 2001–December 2005). For vegetated soil, evapotranspiration alone reduced root-zone (upper 1 m) moisture to a minimum value (25 mm) each year under both isothermal and nonisothermal conditions. Variations in the leaf area index altered the minimum storage values by up to 10 mm. For unvegetated isothermal and nonisothermal simulations, root-zone water storage nearly doubled during the simulation period and created a persistent driving force for downward liquid fluxes below the root zone (total net flux ~1 mm). Total soil water movement during the study period was dominated by thermally driven vapor fluxes. Thermally driven vapor flow and condensation supplemented moisture supplies to plant roots during the driest times of each year. The results show how nonisothermal flow is coupled with plant water uptake, potentially influencing ecohydrologic relations in desert environments.

  3. Assessment of heavy metal pollution in vegetables and relationships with soil heavy metal distribution in Zhejiang province, China.

    PubMed

    Ye, Xuezhu; Xiao, Wendan; Zhang, Yongzhi; Zhao, Shouping; Wang, Gangjun; Zhang, Qi; Wang, Qiang

    2015-06-01

    There are increasing concerns on heavy metal contaminant in soils and vegetables. In this study, we investigated heavy metal pollution in vegetables and the corresponding soils in the main vegetable production regions of Zhejiang province, China. A total of 97 vegetable samples and 202 agricultural soil samples were analyzed for the concentrations of Cd, Pb, As, Hg, and Cr. The average levels of Cd, Pb, and Cr in vegetable samples [Chinese cabbage (Brassica campestris spp. Pekinensis), pakchoi (Brassica chinensis L.), celery (Apium graveolens), tomato (Lycopersicon esculentum), cucumber (Colletotrichum lagenarium), cowpea (Vigna unguiculata), pumpkin (Cucurbita pepo L.), and eggplant (Solanum melongena)] were 0.020, 0.048, and 0.043 mg kg(-1), respectively. The Pb and Cr concentrations in all vegetable samples were below the threshold levels of the Food Quality Standard (0.3 and 0.5 mg kg(-1), respectively), except that two eggplant samples exceeded the threshold levels for Cd concentrations (0.05 mg kg(-1)). As and Hg contents in vegetables were below the detection level (0.005 and 0.002 mg kg(-1), respectively). Soil pollution conditions were assessed in accordance with the Chinese Soil Quality Criterion (GB15618-1995, Grade II); 50 and 68 soil samples from the investigated area exceeded the maximum allowable contents for Cd and Hg, respectively. Simple correlation analysis revealed that there were significantly positive correlations between the metal concentrations in vegetables and the corresponding soils, especially for the leafy and stem vegetables such as pakchoi, cabbage, and celery. Bio-concentration factor values for Cd are higher than those for Pb and Cr, which indicates that Cd is more readily absorbed by vegetables than Pb and Cr. Therefore, more attention should be paid to the possible pollution of heavy metals in vegetables, especially Cd.

  4. The effects of soil moisture, surface roughness, and vegetation on L-band emission and backscatter

    NASA Technical Reports Server (NTRS)

    Wang, James R.; Shiue, J. C.; Engman, Edwin T.; Schmugge, Thomas J.; Mo, Tsan

    1987-01-01

    Measurements performed with SIR-B at 1.28 GHz and an airborne multiple-beam push-broom radiometer at 1.4 GHz over agricultural fields near Fresno, California are examined. A theoretical model (Kirchhoff approximation) was used to assess the effects of surface roughness and vegetation (alfalfa and lettuce) with respect to the responses of microwave emission and backscatter to soil-moisture variations. It is found that the surface roughness plays a dominant role compared to the vegetation cover in the microwave backscatter.

  5. Contamination of commonly consumed raw vegetables with soil transmitted helminth eggs in Mazandaran province, northern Iran.

    PubMed

    Rostami, Ali; Ebrahimi, Maryam; Mehravar, Saeed; Fallah Omrani, Vahid; Fallahi, Shirzad; Behniafar, Hamed

    2016-05-16

    Soil-transmitted helminth (STH) infections are responsible for significant burden of morbidity and mortality worldwide. Consumption of raw vegetables without proper washing is one of the major routes of such infections. We evaluate the prevalence of STH contamination in commonly used vegetables in Mazandaran province, northern Iran. A total of 772 fresh raw vegetables were obtained from retail markets. Each sample was divided into two groups. One group was used as the unwashed sample and the second group was washed with standard washing procedures. Then, samples were examined for helminth eggs by using standard methods. Data analysis was performed using SPSS20. The overall prevalence of STHs was 14.89% (115/772). The rate of STH contamination was significantly higher in warm seasons (20.5%, 79/386) than in cold seasons (9.32%, 36/386) among the unwashed vegetables (OR=2.50; CI 95%=1.64-3.8; P<0.001). No parasites were observed in standard washed samples (OR=271.40; CI 95%=16.84-4373.64; P<0.001). Prevalence of STH contamination was significantly higher in leafy vegetables than root vegetables (OR=1.67; CI 95%=1.09-2.55; P<0.05). The prevalence of STHs species in all the vegetables were as follows: Ascaris lumbricoides (3.36%), Trichuris trichiura (2.2%), hookworms (2.9%), Toxocara spp. (1.68%), Trichostrongylus spp. (1.55), Taenia sp. (0.9%) and Hymenolepis nana (2.2%). The results of the present study emphasized that vegetables are potential risk factor for transmission of helminth infection to human in northern Iran. It is necessary that health authorities trained the consumers to proper and standard washing of vegetables before consumption.

  6. Analysis of modified wet-air oxidation for soil detoxification

    SciTech Connect

    Unterberg, W.; Willms, R.S.; Balinsky, A.M.; Reible, D.D.; Wetzel, D.M.

    1987-09-01

    This report presents the results of research on wet-air oxidation as a method for the destruction of hazardous wastes. For organics in the presence of large amounts of water, the water need not be vaporized during wet-air oxidation, an attractive characteristic for energy conservation. The feasibility of using wet-air oxidation was investigated in terms of the effects of temperature, pressure, and the presence or absence of soil on the oxidation rate of three model compounds. Wet-air oxidation is a semi-commercial process that has been used to treat a variety of weakly toxic chemical wastes and for the regeneration of activated carbon. In the study, wet-air oxidation research was carried out in a 1-liter batch reactor at temperatures from 130 to 275/sup 0/C and pressures from 703-1760 x 10/sup 3/ kg/sq m on three substances: m-xylene, tetrachloroethylene (TCE), and malathion, both with and without addition of soil. Any attempt to balance the effect of residence time and the cost of energy requires an accurate description of the oxidation kinetics for the compound or waste stream in question. Due to the sampling technique used during the investigation and the inherent nature of the wet-air oxidation process, a variety of potential problems with the interpretation and analysis of the raw concentration-time data were encountered during the study.

  7. Occurrence and risk assessment of phthalate esters (PAEs) in vegetables and soils of suburban plastic film greenhouses.

    PubMed

    Wang, Jun; Chen, Gangcai; Christie, Peter; Zhang, Manyun; Luo, Yongming; Teng, Ying

    2015-08-01

    Phthalate esters (PAEs) are suspected of having adverse effects on human health and have been frequently detected in soils and vegetables. The present study investigated their occurrence and composition in plastic film greenhouse soil-vegetable systems and assessed their potential health risks to farmers exposed to these widespread pollutants. Six priority control phthalates, namely dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DnBP), butyl benzyl phthalate (BBP), di-(2-ethylhexyl) phthalate (DEHP) and di-n-octyl phthalate (DnOP), were determined in 44 plastic film greenhouse vegetables and corresponding soils. Total PAEs ranged from 0.51 to 7.16mgkg(-1) in vegetables and 0.40 to 6.20mgkg(-1) in soils with average concentrations of 2.56 and 2.23mgkg(-1), respectively. DnBP, DEHP and DnOP contributed more than 90% of the total PAEs in both vegetables and soils but the proportions of DnBP and DnOP in vegetables were significantly (p<0.05) higher than in soils. The average concentrations of PAEs in pot herb mustard, celery and lettuce were >3.00mgkg(-1) but were <2.50mgkg(-1) in the corresponding soils. Stem and leaf vegetables accumulated more PAEs. There were no clear relationships between vegetable and soil PAEs. Risk assessment indicates that DnBP, DEHP and DnOP exhibited elevated non-cancer risk with values of 0.039, 0.338 and 0.038, respectively. The carcinogenic risk of DEHP was about 3.94×10(-5) to farmers working in plastic film greenhouses. Health risks were mainly by exposure through vegetable consumption and soil ingestion.

  8. Evaluating the potential health risk of toxic trace elements in vegetables: Accounting for variations in soil factors.

    PubMed

    Yang, Yang; Chen, Weiping; Wang, Meie; Li, Yanling; Peng, Chi

    2017-02-06

    Vegetable crop consumption is one of the main sources of dietary exposure to toxic trace elements (TEs). A paired survey of soil and vegetable samples was conducted in 589 agricultural sites in the Youxian prefecture, southern China, to investigate the effect of soil factors on the accumulation of arsenic, cadmium, mercury, and lead in different vegetables. A site-specific model was developed to estimate the health risk from vegetable consumption. The TE concentration varied in different plant species, and rape can be cultivated in contaminated areas for its potential use in restricting the transfer of TE from soil to edible plant parts. The accumulation of TEs in vegetables was governed by multiple factors, mainly element interaction, metal availability (extractable CaCl2 fraction), and soil pH. Soil Zn may promote Cd accumulation in vegetables when soil Cd/Zn ratio>0.02. Cadmium is a major hazardous component. About 80.8% of the adult populations consuming locally produced vegetables had a daily Cd intake risk above the safe standard. Among investigated vegetables, radish is potentially hazardous for populations because of its high consumption rate and high Cd content but low Zn accumulation. The consumption of radish cultivated in highly acidic soil (4soil of near-neutral pH (6soil factors suggests that a site-specific risk assessment is needed for better and safer vegetable production.

  9. Effect of heat waves on VOC emissions from vegetation and urban air quality

    NASA Astrophysics Data System (ADS)

    Churkina, G.; Kuik, F.; Lauer, A.; Bonn, B.; Butler, T. M.

    2015-12-01

    Programs to plant millions of trees in cities around the world aim at the reduction of summer temperatures, increase carbon storage, storm water control, provision of space for recreation, as well as poverty alleviation. Although these multiple benefits speak positively for urban greening programs, the programs do not take into account how close human and natural systems are coupled in urban areas. Elevated temperatures together with anthropogenic emissions of air and water pollutants distinguish the urban system. Urban and sub-urban vegetation responds to ambient changes and reacts with pollutants. Neglecting this coupling may lead to unforeseen drawbacks of urban greening programs. The potential for emissions of volatile organic compounds (VOC) from vegetation combined with anthropogenic emissions to produce ozone has long been recognized. This potential increases under rising temperatures. Here we investigate how heat waves affect emissions of VOC from urban vegetation and corresponding ground-level ozone. In this study we use Weather Research and Forecasting Model with coupled atmospheric chemistry (WRF-CHEM) to quantify these feedbacks in Berlin, Germany during the 2006 heat wave. VOC emissions from vegetation are simulated with MEGAN 2.0 coupled with WRF-CHEM. Our preliminary results indicate that contribution of VOCs from vegetation to ozone formation may increase by more than twofold during the heat wave period. We highlight the importance of the vegetation for urban areas under changing climate and discuss associated tradeoffs.

  10. Mucilaginibacter yixingensis sp. nov., isolated from vegetable soil.

    PubMed

    Jing, Yi-Ting; Wang, Ping; Zhang, Hao; Dong, Wei-Liang; Jing, Yin-Juan; Xiao, Yong-Liang; Cao, Hui

    2016-04-01

    A Gram-reaction-negative, aerobic, non-motile, non-spore-forming, rod-shaped bacterium, designated YX-36T, was isolated from a vegetable plot in Yixing, Jiangsu province, China. The strain grew at 15-37 °C (optimally at 37 °C), at pH 6.0-9.5 (optimally at pH 6.5) and in the presence of 0-1% (w/v) NaCl (optimally without NaCl). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain YX-36T was related most closely to Mucilaginibacter herbaticus DR-9T (96.88% similarity), followed by Mucilaginibacter sabulilitoris SMS-12T (95.78%), Mucilaginibacter polysacchareus DR-f3T (95.77%) and Mucilaginibacter polysacchareus DRP28T (95.77%). The DNA G+C content of strain YX-36T was 47.2 mol%. The only isoprenoid quinone was menaquinone 7 (MK-7). The major polar lipids were phosphatidylethanolamine and aminophospholipid. The major fatty acids were iso-C15:0, summed feature 3 (iso-C15:0 2-OH/C16:1ω7c) and iso-C17:0 3-OH. On the basis of phenotypic, chemotaxonomic and phylogenetic data, strain YX-36T represents a novel species of the genus Mucilaginibacter, for which the name Mucilaginibacter yixingensis sp. nov. is proposed. The type strain is YX-36T (=DSM 26809T=CCTCC AB 2012880T).

  11. Modeled Impacts of Cover Crops and Vegetative Barriers on Corn Stover Availability and Soil Quality

    SciTech Connect

    Ian J. Bonner; David J. Muth Jr.; Joshua B. Koch; Douglas L. Karlen

    2014-06-01

    Environmentally benign, economically viable, and socially acceptable agronomic strategies are needed to launch a sustainable lignocellulosic biofuel industry. Our objective was to demonstrate a landscape planning process that can ensure adequate supplies of corn (Zea mays L.) stover feedstock while protecting and improving soil quality. The Landscape Environmental Assessment Framework (LEAF) was used to develop land use strategies that were then scaled up for five U.S. Corn Belt states (Nebraska, Iowa, Illinois, Indiana, and Minnesota) to illustrate the impact that could be achieved. Our results show an annual sustainable stover supply of 194 million Mg without exceeding soil erosion T values or depleting soil organic carbon [i.e., soil conditioning index (SCI)?>?0] when no-till, winter cover crop, and vegetative barriers were incorporated into the landscape. A second, more rigorous conservation target was set to enhance soil quality while sustainably harvesting stover. By requiring erosion to be <1/2 T and the SCI-organic matter (OM) subfactor to be >?0, the annual sustainable quantity of harvestable stover dropped to148 million Mg. Examining removal rates by state and soil resource showed that soil capability class and slope generally determined the effectiveness of the three conservation practices and the resulting sustainable harvest rate. This emphasizes that sustainable biomass harvest must be based on subfield management decisions to ensure soil resources are conserved or enhanced, while providing sufficient biomass feedstock to support the economic growth of bioenergy enterprises.

  12. Use of Radar Vegetation Index (RVI) in Passive Microwave Algorithms for Soil Moisture Estimates

    NASA Astrophysics Data System (ADS)

    Rowlandson, T. L.; Berg, A. A.

    2013-12-01

    The Soil Moisture Active Passive (SMAP) satellite will provide a unique opportunity for the estimation of soil moisture by having simultaneous radar and radiometer measurements available. As with the Soil Moisture and Ocean Salinity (SMOS) satellite, the soil moisture algorithms will need to account for the contribution of vegetation to the brightness temperature. Global maps of vegetation volumetric water content (VWC) are difficult to obtain, and the SMOS mission has opted to estimate the optical depth of standing vegetation by using a relationship between the VWC and the leaf area index (LAI). LAI is estimated from optical remote sensing or through soil-vegetation-atmosphere transfer modeling. During the growing season, the VWC of agricultural crops can increase rapidly, and if cloud cover exists during an optical acquisition, the estimation of LAI may be delayed, resulting in an underestimation of the VWC and overestimation of the soil moisture. Alternatively, the radar vegetation index (RVI) has shown strong correlation and linear relationship with VWC for rice and soybeans. Using the SMAP radar to produce RVI values that are coincident to brightness temperature measurements may eliminate the need for LAI estimates. The SMAP Validation Experiment 2012 (SMAPVEX12) was a cal/val campaign for the SMAP mission held in Manitoba, Canada, during a 6-week period in June and July, 2012. During this campaign, soil moisture measurements were obtained for 55 fields with varying soil texture and vegetation cover. Vegetation was sampled from each field weekly to determine the VWC. Soil moisture measurements were taken coincident to overpasses by an aircraft carrying the Passive and Active L-band System (PALS) instrumentation. The aircraft flew flight lines at both high and low altitudes. The low altitude flight lines provided a footprint size approximately equivalent to the size of the SMAPVEX12 field sites. Of the 55 field sites, the low altitude flight lines provided

  13. Uptake of explosives from contaminated soil by vegetation at the Joliet Army Ammunition Plant

    SciTech Connect

    Schneider, J.F.; Tomczyk, N.A.; Zellmer, S.D.; Banwart, W.L.; Houser, W.P.

    1994-06-01

    This study examines the uptake of explosives by vegetation growing on soils contaminated by 2,4,6-trinitrotoluene (TNT) in Group 61 at the Joliet Army Ammunition Plant (JAAP). Plant materials and soil from the root zone were sampled and analyzed to determine TNT uptake under natural field conditions. Standard USATHAMA methods were used to determine concentrations of explosives, their derivatives, and metabolites in the soil samples. No- explosives were detected in the aboveground portion of any plant sample. However, results indicate that TNT, 2-aminodinitrotoluene (2-ADNT), and/or 4-ADNT were present in some root samples. The presence of 2-ADNT and 4-ADNT increases the likelihood that explosives were taken up by plant roots, as opposed to their presence resulting from external soil contamination.

  14. Measurement of directional thermal infrared emissivity of vegetation and soils

    SciTech Connect

    Norman, J.M.; Balick, L.K.

    1995-10-01

    A new method has been developed for measuring directional thermal emissivity as a function of view angle for plant canopies and soils using two infrared thermometers each sensitive to a different wavelength band. By calibrating the two infrared thermometers to 0.1C consistency, canopy directional emissivity can be estimated with typical errors less than 0.005 in the 8--14 um wavelength band, depending on clarity of the sky and corrections for CO{sub 2} absorption by the atmosphere. A theoretical justification for the method is developed along with an error analysis. Laboratory measurements were used to develop corrections for CO{sub 2}, absorption and a field calibration method is used to obtain the necessary 0.1C consistency for relatively low cost infrared thermometers. The emissivity of alfalfa (LAI=2.5) and corn (LAI=3.2) was near 0.995 and independent of view angle. Individual corn leaves had an emissivity of 0.97. A wheat (LAI=3.0) canopy had an emissivity of 0.985 at nadir and 0.975 at 75 degree view angle. The canopy emissivity values tend to be higher than values in the literature, and are useful for converting infrared thermometer measurements to kinetic temperature and interpreting satellite thermal observations.

  15. Environmental factors influencing soil testate amoebae in herbaceous and shrubby vegetation along an altitudinal gradient in subarctic tundra (Abisko, Sweden).

    PubMed

    Tsyganov, Andrey N; Milbau, Ann; Beyens, Louis

    2013-05-01

    Shifts in community composition of soil protozoa in response to climate change may substantially influence microbial activity and thereby decomposition processes. However, effects of climate and vegetation on soil protozoa remain poorly understood. We studied the distribution of soil testate amoebae in herbaceous and shrubby vegetation along an altitudinal gradient (from below the treeline at 500 m to the mid-alpine region at 900 m a.s.l.) in subarctic tundra. To explain patterns in abundance, species diversity and assemblage composition of testate amoebae, a data set of microclimate and soil chemical characteristics was collected. Both elevation and vegetation influenced the assemblage composition of testate amoebae. The variation was regulated by interactive effects of summer soil moisture, winter soil temperature, soil pH and nitrate ion concentrations. Besides, soil moisture regulated non-linear patterns in species richness across the gradient. This is the first study showing the effects of winter soil temperatures on species composition of soil protozoa. The effects could be explained by specific adaptations of testate amoebae such as frost-resistant cysts allowing them to survive low winter temperatures. We conclude that the microclimate and soil chemical characteristics are the main drivers of changes in protozoan assemblage composition in response to elevation and vegetation.

  16. Salmonella enterica Serovar Typhimurium and Escherichia coli Contamination of Root and Leaf Vegetables Grown in Soils with Incorporated Bovine Manure

    PubMed Central

    Natvig, Erin E.; Ingham, Steven C.; Ingham, Barbara H.; Cooperband, Leslie R.; Roper, Teryl R.

    2002-01-01

    Bovine manure, with or without added Salmonella enterica serovar Typhimurium (three strains), was incorporated into silty clay loam (SCL) and loamy sand (LS) soil beds (53- by 114-cm surface area, 17.5 cm deep) and maintained in two controlled-environment chambers. The S. enterica serovar Typhimurium inoculum was 4 to 5 log CFU/g in manure-fertilized soil. The conditions in the two environmental chambers, each containing inoculated and uninoculated beds of manure-fertilized soil, simulated daily average Madison, Wis., weather conditions (hourly temperatures, rainfall, daylight, and humidity) for a 1 March or a 1 June manure application and subsequent vegetable growing seasons ending 9 August or 28 September, respectively. Core soil samples were taken biweekly from both inoculated and uninoculated soil beds in each chamber. Radishes, arugula, and carrots were planted in soil beds, thinned, and harvested. Soils, thinned vegetables, and harvested vegetables were analyzed for S. enterica serovar Typhimurium and Escherichia coli (indigenous in manure). After the 1 March manure application, S. enterica serovar Typhimurium was detected at low levels in both soils on 31 May, but not on vegetables planted 1 May and harvested 12 July from either soil. After the 1 June manure application, S. enterica serovar Typhimurium was detected in SCL soil on 7 September and on radishes and arugula planted in SCL soil on 15 August and harvested on 27 September. In LS soil, S. enterica serovar Typhimurium died at a similar rate (P ≥ 0.05) after the 1 June manure application and was less often detected on arugula and radishes harvested from this soil compared to the SCL soil. Pathogen levels on vegetables were decreased by washing. Manure application in cool (daily average maximum temperature of <10°C) spring conditions is recommended to ensure that harvested vegetables are not contaminated with S. enterica serovar Typhimurium. Manure application under warmer (daily average maximum

  17. Effects of disturbance and vegetation type on total and methylmercury in boreal peatland and forest soils.

    PubMed

    Braaten, Hans Fredrik Veiteberg; de Wit, Heleen A

    2016-11-01

    Mercury (Hg) concentrations in freshwater fish relates to aquatic Hg concentrations, which largely derives from soil stores of accumulated atmospheric deposition. Hg in catchment soils as a source for aquatic Hg is poorly studied. Here we test if i) peatland soils produce more methylmercury (MeHg) than forest soils; ii) total Hg (THg) concentrations in top soils are determined by atmospheric inputs, while MeHg is produced in the soils; and iii) soil disturbance promotes MeHg production. In two small boreal catchments, previously used in a paired-catchment forest harvest manipulation study, forest soils and peatlands were sampled and analysed for Hg species and additional soil chemistry. In the undisturbed reference catchment, soils were sampled in different vegetation types, of varying productivity as reflected in tree density, where historical data on precipitation and throughfall Hg and MeHg fluxes were available. Upper soil THg contents were significantly correlated to throughfall inputs of Hg, i.e. lowest in the tree-less peatland and highest in the dense spruce forest. For MeHg, top layer concentrations were similar in forest soils and peatlands, likely related to atmospheric input and local production, respectively. The local peatland MeHg production was documented through significantly higher MeHg-to-THg ratios in the deeper soil layer samples. In the disturbed catchment, soils were sampled in and just outside wheeltracks in an area impacted by forest machinery. Here, MeHg concentrations and the MeHg-to-THg ratios in the upper 5 cm were weakly significantly (p = 0.07) and significantly (p = 0.04) different in and outside of the wheeltracks, respectively, suggesting that soil disturbance promotes methylation. Differences in catchment Hg and MeHg streamwater concentrations were not explained by soil Hg and MeHg information, perhaps because hydrological pathways are a stronger determinant of streamwater chemistry than small variations in soil chemistry

  18. Constructing vegetation productivity equations by employing undisturbed soils data: An Oliver County, North Dakota case study

    SciTech Connect

    Burley, J.B.; Polakowski, K.J.; Fowler, G.

    1996-12-31

    Surface mine reclamation specialists have been searching for predictive methods to assess the capability of disturbed soils to support vegetation growth. We conducted a study to develop a vegetation productivity equation for reclaiming surface mines in Oliver County, North Dakota, thereby allowing investigators to quantitatively determine the plant growth potential of a reclaimed soil. The study examined the predictive modeling potential for both agronomic crops and woody plants, including: wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), oat (Avena sativa L.), corn (Zea mays L.), grass and legume mixtures, Eastern red cedar (Juniperus virginiana L.), Black Hills spruce (Picea glauca var. densata Bailey), Colorado spruce (Picea pungens Engelm.), ponderosa pine (Pinus ponderosa var. scope Engelm.), green ash (Fraxinus pennsylvanica Marsh.), Eastern cottonwood Populus deltoides (Bart. ex Marsh.), Siberian elm (Ulmus pumila L.), Siberian peashrub (Caragana arborescens Lam), American plum (Prunus americans Marsh.), and chokecherry ( Prunus virginiana L.). An equation was developed which is highly significant (p<0.0001), explaining 81.08% of the variance (coefficient of multiple determination=0.8108), with all regressors significant (p{le}0.048, Type II Sums of Squares). The measurement of seven soil parameters are required to predict soil vegetation productivity: percent slope, available water holding capacity, percent rock fragments, topographic position, electrical conductivity, pH, and percent organic matter. While the equation was developed from data on undisturbed soils, the equation`s predictions were positively correlated (0.71424, p{le}0.0203) with a small data set (n=10) from reclaimed soils.

  19. Vegetation Influences on Long-Term Carbon Stabilization in Soils: a Coast Redwood-Prairie Comparison

    NASA Astrophysics Data System (ADS)

    Mambelli, S.; Burton, S. D.; McFarlane, K. J.; Torn, M. S.; Dawson, T. E.

    2010-12-01

    Complex interactions and feedbacks among soil, biota, climate, and parent material determine the long-term pathways and mechanisms of carbon persistence in soils. While it is well known that litter chemistry influences litter decay on annual-decadal timescales, its impact on long-term SOM storage is still under debate. We tested the role of the substrate available to decomposers in determining decomposition and sequestration of carbon by comparing two contrasting ecosystems representing end-members in terms of tissue lifespan and litter recalcitrance, an old-growth redwood forest and an adjacent tree-less prairie, at one site with identical climate, topography, and parent material. Solid-state CP MAS 13C NMR was applied to investigate the chemical structure of vegetation tissues (aboveground and belowground), and of soil fractions (particulate organic carbon free in the soil matrix and particulate organic carbon located inside soil aggregates, or free and occluded light fraction (LF), respectively) at different depths. In addition, the carbon stability of these soil density fractions was estimated based on radiocarbon modeling. Preliminary NMR results showed strong differences between redwood and prairie tissues, and between litters and surface soil fractions. On average, redwood litter contained more aromatic carbon (C and O substituted aryl C), more lipids (alkyl C) and fewer carbohydrates (O-alkyl C) than prairie litter. Under both vegetation types we found that the chemical structure changed consistently from litter to free LF, and from free LF to occluded LF. The alkyl C signal intensity increased, while the O-alkyl C fraction decreased, but more strongly at the redwood forest. The proportion of aromatic functional groups in the total organic matter (aromaticity) was always higher in the soil fractions compared with the original litters. Redwood soil fractions aromaticity was 0.32 (+80% from litter), while prairie soil fractions aromaticity varied from 0

  20. Using Distributed-Hydrology-Soil-Vegetation Model to Study Road Effects on Stream flow and Soil Moisture

    NASA Astrophysics Data System (ADS)

    Cuo, L.; Giambelluca, T. W.; Ziegler, A. D.; Nullet, M. A.

    2003-12-01

    The distributed-hydrology-soil-vegetation model (DHSVM) was applied in Pang Khum Experimental Watershed (PKEW), located near 19.05\\deg N, 98.65\\deg E in the mountainous region of northern Thailand, headwaters of the Chao Phraya River system. PKEW has a highly seasonal rainfall regime, with 90% of the annual 1200-1400 mm rainfall occurring during the southwest summer monsoon. The elevation of PKEW ranges from approximately 1100 to 1500 m. Total road area including road banks is about 1.2% of the basin area. About 57% of the road area occurs on slopes steeper than 10%. All roads are unpaved. Land cover in PKEW is affected by swidden agriculture. Six land cover and nine soil classes are identified in the basin. We have been working in the area since 1997 as part of the Thailand Roads Project (TRP). Within the basin, we are monitoring microclimate at two sites, soil moisture at four sites, and rainfall at five sites. Streamflow is measured at the outlet. Based on digital elevation data, DHSVM explicitly accounts for the spatial distribution of the stream and road networks, soil depth, soil and vegetation types. The model run period, including warm up, calibration and validation, is from August 1997 to January 2001. Field measurements provide forcing data, calibration data, and guidance in parameter selection. Model calibration and validation were done by aggregating simulated hourly soil moisture and stream flow into daily values and comparing them with aggregated daily measurements. For the calibration period, RMSEs of soil moisture and streamflow were lower than the observed variability as represented by the standard deviation, median absolute deviation, and (for stream flow) interquartile range. Model performance drops in validation period, but RMSEs remain near or lower than observed variability. We ran DHSVM with and without roads to examine their effects. Significant effects of roads were found despite the very low proportion of the watershed covered by roads

  1. The effects of vegetation and soil hydraulic properties on passive microwave sensing of soil moisture: Data report for the 1982 fiels experiments

    NASA Technical Reports Server (NTRS)

    Oneill, P.; Jackson, T.; Blanchard, B. J.; Vandenhoek, R.; Gould, W.; Wang, J.; Glazar, W.; Mcmurtrey, J., III

    1983-01-01

    Field experiments to (1) study the biomass and geometrical structure properties of vegetation canopies to determine their impact on microwave emission data, and (2) to verify whether time series microwave data can be related to soil hydrologic properties for use in soil type classification. Truck mounted radiometers at 1.4 GHz and 5 GHz were used to obtain microwave brightness temperatures of bare vegetated test plots under different conditions of soil wetness, plant water content and canopy structure. Observations of soil moisture, soil temperature, vegetation biomass and other soil and canopy parameters were made concurrently with the microwave measurements. The experimental design and data collection procedures for both experiments are documented and the reduced data are presented in tabular form.

  2. Changes in soils and vegetation in a Mediterranean coastal salt marsh impacted by human activities

    NASA Astrophysics Data System (ADS)

    Álvarez-Rogel, J.; Jiménez-Cárceles, F. J.; Roca, M. J.; Ortiz, R.

    2007-07-01

    This paper reports changes in vegetation distribution and species cover in relation to soil factors and hydrology in a semiarid Mediterranean salt marsh adjacent to the Mar Menor saline lagoon. Species cover, soil salinity, and the groundwater level were monitored between 1991 and 1993 and between 2002 and 2004, and total organic carbon, total nitrogen, total phosphorus, nitrates, ammonium and exchangeable phosphorus were measured in the soils in both study periods. In addition, three soil profiles were described in August 1992 and August 2004. The results indicate an elevation of the water table throughout the 13-year period, which was attributable to water flowing from areas with intensive agriculture. Flooding increased and soil salinity dropped in the most saline sites and increased in the least saline ones. The morphology of the soil profiles reflected the increase in flooding periods, due to the appearance of a greyer matrix in the deeper horizons and a more diffuse pattern of Fe mottles. Following these environmental changes, Sarcocornia fruticosa, Phragmites australis and Juncus maritimus strongly expanded at the wettest sites, which led to the disappearance of the original zonation pattern. The cover of Limonium delicatulum, in turn, decreased with the increase in moisture but increased following the increase in salinity. Changes in soil nutrients were only very evident in the sandy soils of the beach, probably due to the influence of organic debris deposited on the shoreline by the storms and due to the strong increase in the colonisation of this habitat by perennial species. According to the results obtained, control measures are needed in order to preserve habitat diversity in this and other salt marshes of this area. Monitoring of the vegetation distribution could be a useful tool to identify environmental impacts, in order to implement remedial actions.

  3. Heavy metal concentrations in soils and vegetation in urban areas of Quezon City, Philippines.

    PubMed

    Navarrete, Ian A; Gabiana, Christella C; Dumo, Joan Ruby E; Salmo, Severino G; Guzman, Maria Aileen Leah G; Valera, Nestor S; Espiritu, Emilyn Q

    2017-04-01

    Limited data have been published on the chemistry of urban soils and vegetation in the Philippines. The aim of this study is to quantify the concentrations of heavy metals (i.e., Cr, Ni, Cu, Zn, and Pb) in soils and vegetation in the urban landscape of Quezon City, Philippines, and to elucidate the relationships between soil properties and the concentration of heavy metals pertaining to different land uses [i.e., protected forest (LM), park and wildlife area (PA), landfill (PL), urban poor residential and industrial areas (RA), and commercial areas (CA)]. Soil (0-15 cm) and senescent plant leaves were collected and were analyzed for soil properties and heavy metal concentrations. Results revealed that the concentrations of heavy metals (i.e., Cr, Ni, Cu, Zn, and Pb) in urban soils were higher in areas where anthropogenic activities or disturbance (PL, RA, and CA) were dominant as compared to the less disturbed areas (LM and PA). Organic matter and available phosphorous were strongly correlated with heavy metal concentrations, suggesting that heavy metal concentrations were primarily controlled by these soil properties. The average foliar heavy metal concentrations varied, ranging from 0 to 0.4 mg/kg for Cd, 0-10 mg/kg for Cr, 2-22 mg/kg for Cu, 0-5 mg/kg for Pb, and 11-250 mg/kg for Zn. The concentrations of Cd and Cr exceeded the critical threshold concentrations in some plants. Leaves of plants growing in PL (i.e., landfill) showed the highest levels of heavy metal contamination. Our results revealed that anthropogenic activities and disturbance caused by the rapid urbanization of the city are major contributors to the heavy metal accumulation and persistence in the soils in these areas.

  4. Seasonality in ENSO-related precipitation, river discharges, soil moisture, and vegetation index in Colombia

    NASA Astrophysics Data System (ADS)

    Poveda, GermáN.; Jaramillo, Alvaro; Gil, Marta MaríA.; Quiceno, Natalia; Mantilla, Ricardo I.

    2001-08-01

    An analysis of hydrologic variability in Colombia shows different seasonal effects associated with El Niño/Southern Oscillation (ENSO) phenomenon. Spectral and cross-correlation analyses are developed between climatic indices of the tropical Pacific Ocean and the annual cycle of Colombia's hydrology: precipitation, river flows, soil moisture, and the Normalized Difference Vegetation Index (NDVI). Our findings indicate stronger anomalies during December-February and weaker during March-May. The effects of ENSO are stronger for streamflow than for precipitation, owing to concomitant effects on soil moisture and evapotranspiration. We studied time variability of 10-day average volumetric soil moisture, collected at the tropical Andes of central Colombia at depths of 20 and 40 cm, in coffee growing areas characterized by shading vegetation ("shaded coffee"), forest, and sunlit coffee. The annual and interannual variability of soil moisture are highly intertwined for the period 1997-1999, during strong El Niño and La Niña events. Soil moisture exhibited greater negative anomalies during 1997-1998 El Niño, being strongest during the two dry seasons that normally occur in central Colombia. Soil moisture deficits were more drastic at zones covered by sunlit coffee than at those covered by forest and shaded coffee. Soil moisture responds to wetter than normal precipitation conditions during La Niña 1998-1999, reaching maximum levels throughout that period. The probability density function of soil moisture records is highly skewed and exhibits different kinds of multimodality depending upon land cover type. NDVI exhibits strong negative anomalies throughout the year during El Niños, in particular during September-November (year 0) and June-August (year 0). The strong negative relation between NDVI and El Niño has enormous implications for carbon, water, and energy budgets over the region, including the tropical Andes and Amazon River basin.

  5. Herbaceous vegetation productivity, persistence, and metals uptake on a biosolids-amended mine soil

    SciTech Connect

    Evanylo, G.K.; Abaye, A.O.; Dundas, C.; Zipper, C.E.; Lemus, R.; Sukkariyah, B.; Rockett, J.

    2005-10-01

    The selection of plant species is critical for the successful establishment and long-term maintenance of vegetation on reclaimed surface mined soils. A study was conducted to assess the capability of 16 forage grass and legume species in monocultures and mixes to establish and thrive on a reclaimed Appalachian surface mine amended with biosolids. The 0.15-ha coarse-textured, rocky, non-acid forming mined site was prepared for planting by grading to a 2% slope and amending sandstone overburden materials with a mixture of composted and dewatered, anaerobically digested biosolids at a rate of 368 Mg ha{sup -1} (dry weight). The high rate of biosolids applied provided favorable soil chemical properties but could not overcome physical property limitations due to shallow undeveloped soil perched atop a compacted soil layer at 25 cm depth. The plant species whose persistence and biomass production were the greatest after a decade or more of establishment (i.e., switchgrass, sericea lespedeza, reed canarygrass, tall fescue, and crownvetch) shared the physiological and reproductive characteristics of low fertility requirements, drought and moisture tolerance, and propagation by rhizome and/or stolons. Of these five species, two (tall fescue and sericea lespedeza) are or have been seeded commonly on Appalachian coal surface mines, and often dominate abandoned pasture sites. Despite the high rates of heavy metal-bearing biosolids applied to the soil, plant uptake of Cd, Cu, Ni, and Zn were well within critical concentrations more than a decade after establishment of the vegetation.

  6. Use of LANDSAT images of vegetation cover to estimate effective hydraulic properties of soils

    NASA Technical Reports Server (NTRS)

    Eagleson, Peter S.; Jasinski, Michael F.

    1988-01-01

    The estimation of the spatially variable surface moisture and heat fluxes of natural, semivegetated landscapes is difficult due to the highly random nature of the vegetation (e.g., plant species, density, and stress) and the soil (e.g., moisture content, and soil hydraulic conductivity). The solution to that problem lies, in part, in the use of satellite remotely sensed data, and in the preparation of those data in terms of the physical properties of the plant and soil. The work was focused on the development and testing of a stochastic geometric canopy-soil reflectance model, which can be applied to the physically-based interpretation of LANDSAT images. The model conceptualizes the landscape as a stochastic surface with bulk plant and soil reflective properties. The model is particularly suited for regional scale investigations where the quantification of the bulk landscape properties, such as fractional vegetation cover, is important on a pixel by pixel basis. A summary of the theoretical analysis and the preliminary testing of the model with actual aerial radiometric data is provided.

  7. Algal biochar enhances the re-vegetation of stockpiled mine soils with native grass.

    PubMed

    Roberts, David A; Cole, Andrew J; Paul, Nicholas A; de Nys, Rocky

    2015-09-15

    In most countries the mining industry is required to rehabilitate disturbed land with native vegetation. A typical approach is to stockpile soils during mining and then use this soil to recreate landforms after mining. Soil that has been stockpiled for an extended period typically contains little or no organic matter and nutrient, making soil rehabilitation a slow and difficult process. Here, we take freshwater macroalgae (Oedogonium) cultivated in waste water at a coal-fired power station and use it as a feedstock for the production of biochar, then use this biochar to enhance the rehabilitation of two types of stockpiled soil - a ferrosol and a sodosol - from the adjacent coal mine. While the biomass had relatively high concentrations of some metals, due to its cultivation in waste water, the resulting biochar did not leach metals into the pore water of soil-biochar mixtures. The biochar did, however, contribute essential trace elements (particularly K) to soil pore water. The biochar had very strong positive effects on the establishment and growth of a native plant (Kangaroo grass, Themeda australis) in both of the soils. The addition of the algal biochar to both soils at 10 t ha(-1) reduced the time to germination by the grass and increased the growth and production of plant biomass. Somewhat surprisingly, there was no beneficial effect of a higher application rate (25 t ha(-1)) of the biochar in the ferrosol, which highlights the importance of matching biochar application rates to the requirements of different types of soil. Nevertheless, we demonstrate that algal biochar can be produced from biomass cultivated in waste water and used at low application rates to improve the rehabilitation of a variety of soils typical of coal mines. This novel process links biomass production in waste water to end use of the biomass in land rehabilitation, simultaneously addressing two environmental issues associated with coal-mining and processing.

  8. Evaluation of the assimilation of As by vegetables in contaminated soils submitted to a remediation process

    NASA Astrophysics Data System (ADS)

    Pérez-Sirvent, Carmen; Martinez Sanchez, Maria Jose; Agudo, Ines; Belen Martinez, Lucia; Bech, Jaume

    2016-04-01

    A greenhouse trial was carried out to evaluate the assimilation of heavy metals by three types of plants (lettuce, onion and broccoli), different parts of which are destined for human and farm animals consumption (leaves, roots, fruits). The experiments were carried out to check the validity of the use of calcareous materials to recover soils contaminated with heavy metals. The aim of this work was to apply a technology for decontamination to ensure that As do not enter into the trophic chain at risky levels and analyze and to assess the risk pre and post operational of the different treatments proposed. The materials used was a soils to be remediated (mining soils) and the materials used for remediation were lime filler and Construction and Demolition Waste (CDW). The plants were cultivated in greenhouse with several types of soil. Five experiments were used, namely, Tc (contaminated soil), T1 (uncontaminated soil (blank soil)), T2 (50% T1 + 50% Tc), T3 (Tc + (25%) lime residues coming from quarries) and T4 (Tc + (25%) residues coming from demolition and construction activities). The entire project involves twenty experiments which were prepared from soils highly contaminated mixed with two types of calcareous materials. The total As content of the soils samples, rhizosphere and vegetable samples, were measured and the translocation factor (TF), which is defined as the ratio of metal concentration in the leaves or shoots to the roots, and the Bioconcentration factor (BCF), which is defined as the ratio of metal concentration in the roots to that in soil were calculated. The use of CDR is shown to be a suitable way for remediating soils contaminated by metals. The methodology permits a revalorization of CDW.

  9. Soil drainage and vegetation controls of nitrogen transformation rates in forest soils, southern Quebec

    NASA Astrophysics Data System (ADS)

    Ullah, Sami; Moore, Tim R.

    2009-03-01

    We investigated the influence of soil drainage class and tree species on nitrogen (N) mineralization and nitrification rates in two forest catenas in southern Quebec. Monthly net N mineralization and nitrification rates were determined along transects running from well-drained to poorly drained soils for 2 years through in situ incubation of homogenized soils. Potential N transformation rates in soils under American beech, sugar maple, and eastern hemlock trees were determined through incubation of homogenized soils in the laboratory under two different moisture regimes (50 and 100% water by volume) mimicking well-drained and poorly drained soil conditions in the two watersheds. Field-based N mineralization rates averaged 38 ± 6 mg m-2 d-1 in well-drained soils, while those in the poorly drained soils averaged 17 ± 5 mg N m-2 d-1. Similarly, net nitrification rates in well-drained soils (18 ± 4 mg N m-2 d-1) were 3 times greater than those in poorly drained soils (6 ± 3 mg N m-2 d-1). Laboratory-based potential N mineralization rates in soils ranked sugar maple > American beech > eastern hemlock under both well-drained (incubated at 50% water by volume) and poorly drained soil conditions (incubated at 100% water by volume). Potential nitrification rates ranked sugar maple > American beech > eastern hemlock under well-drained soil conditions, while under poorly drained conditions, American beech > sugar maple ≥ eastern hemlock. Nitrification enzyme activity determined through a soil slurry method correlated significantly with field-based nitrification rates. Differences in soil volumetric water contents, leaf litter N input, and soil C:N ratios, as surrogates of soil drainage and floristic heterogeneity, respectively, correlated significantly with field-based N mineralization and nitrification rates. Field-based N mineralization and nitrification rates were higher in summer than in early spring and autumn. Soil drainage class and tree species exert marked

  10. Variability in apparent soil organic carbon turnover times across climate zones and vegetation classes

    NASA Astrophysics Data System (ADS)

    Khomik, M.; Reichstein, M.; Schrumpf, M.; Beer, C.; Curiel Yuste, J.; Janssens, I.; Luyssaert, S.; Subke, J.; Trumbore, S.; Wutzler, T.; Fluxnet Lathuile: Www. Fluxdata. Org

    2011-12-01

    Our understanding about the climatic controls on the rate of soil organic carbon (SOC) decomposition is still limited and greatly debated, especially the temperature sensitivity of SOC decomposition. Some argue that SOC turnover time (TO) decreases exponentially with increasing temperatures, while others disagree. Based on a number of assumptions, we calculated the ratio between soil CO2 efflux and soil bulk carbon stocks, from which we obtained an estimate of apparent TO for bulk soils across a selection of forested sites around the globe. We used data collected from site-PIs and from recently-available databases of: soil chamber flux measurements (Global soil respiration database: code.google.com/p/srdb/), ecosystem carbon flux measurements (FLUXNET LaThuile dataset: www.fluxdata.org), and global soil carbon stock estimates (Harmonized world soil database: www.iiasa.ac.at/Research/LUC/External-World-soil-database/HTML/). We investigated across-site variability of these apparent TO values in relation to climate (i.e. site's mean annual temperature, MAT, and total annual precipitation, TAP) and vegetation classes (i.e. broadleaf deciduous, needle-leaf deciduous, broadleaf evergreen, and needle-leaf evergreen). We found that, when all data points were considered, TO decreased exponentially with increasing MAT and TAP, in accordance with past studies, although the relationship with TAP was not as strong as with MAT. The overall negative exponential relationship was maintained even when the data was analyzed under the combined effects of MAT and TAP and vegetation class. TO at sites with low annual precipitation and low mean annual temperatures were high (i.e. the rate of decomposition was low). However, we also found that this overall global exponential relationship was largely driven by the difference in TO between sites located in the boreal climate zone and sites located in the other climate zones considered (i.e. tropical, Mediterranean and temperate climate

  11. How sedge meadow soils, microtopography, and vegetation respond to sedimentation

    USGS Publications Warehouse

    Werner, K.J.; Zedler, Joy B.

    2002-01-01

    The expansion of urban and agricultural activities in watersheds of the Midwestern USA facilitates the conversion of species-rich sedge meadows to stands of Phalaris arundinacea and Typha spp. We document the role of sediment accumulation in this process based on field surveys of three sedge meadows dominated by Carex stricta, their adjacent Phalaris or Typha stands, and transitions from Carex to these invasive species. The complex microtopography of Carex tussocks facilitates the occurrence of other native species. Tussock surface area and species richness were positively correlated in two marshes (r2 = 0.57 and 0.41); on average, a 33-cm-tall tussock supported 7.6 species. Phalaris also grew in tussock form in wetter areas but did not support native species. We found an average of 10.5 Carex tussocks per 10-m transect, but only 3.5 Phalaris tussocks. Microtopographic relief, determined with a high-precision GPS, measured 11% greater in Carex meadows than Phalaris stands. Inflowing sediments reduced microtopographic variation and surface area for native species. We calculated a loss of one species per 1000 cm2 of lost tussock surface area, and loss of 1.2 species for every 10-cm addition of sediment over the sedge meadow surface. Alluvium overlying the sedge meadow soil had a smaller proportion of organic matter content and higher dry bulk density than the buried histic materials. We conclude that sedimentation contributes to the loss of native species in remnant wetlands. ?? 2002, The Society of Wetland Scientists.

  12. Relating trends in land surface-air temperature difference to soil moisture and evapotranspiration

    NASA Astrophysics Data System (ADS)

    Veal, Karen; Taylor, Chris; Gallego-Elvira, Belen; Ghent, Darren; Harris, Phil; Remedios, John

    2016-04-01

    Soil water is central to both physical and biogeochemical processes within the Earth System. Drying of soils leads to evapotranspiration (ET) becoming limited or "water-stressed" and is accompanied by rises in land surface temperature (LST), land surface-air temperature difference (delta T), and sensible heat flux. Climate models predict sizable changes to the global water cycle but there is variation between models in the time scale of ET decay during dry spells. The e-stress project is developing novel satellite-derived diagnostics to assess the ability of Earth System Models (ESMs) to capture behaviour that is due to soil moisture controls on ET. Satellite records of LST now extend 15 years or more. MODIS Terra LST is available from 2000 to the present and the Along-Track Scanning Radiometer (ATSR) LST record runs from 1995 to 2012. This paper presents results from an investigation into the variability and trends in delta T during the MODIS Terra mission. We use MODIS Terra and MODIS Aqua LST and ESA GlobTemperature ATSR LST with 2m air temperatures from reanalyses to calculate trends in delta T and "water-stressed" area. We investigate the variability of delta T in relation to soil moisture (ESA CCI Passive Daily Soil Moisture), vegetation (MODIS Monthly Normalized Difference Vegetation Index) and precipitation (TRMM Multi-satellite Monthly Precipitation) and compare the temporal and spatial variability of delta T with model evaporation data (GLEAM). Delta T anomalies show significant negative correlations with soil moisture, in different seasons, in several regions across the planet. Global mean delta T anomaly is small (magnitude mostly less than 0.2 K) between July 2002 and July 2008 and decreases to a minimum in early 2010. The reduction in delta T anomaly coincides with an increase in soil moisture anomaly and NDVI anomaly suggesting an increase in evapotranspiration and latent heat flux with reduced sensible heat flux. In conclusion there have been

  13. Spatial variation in vegetation productivity trends, fire disturbance, and soil carbon across arctic-boreal permafrost ecosystems

    NASA Astrophysics Data System (ADS)

    Loranty, Michael M.; Liberman-Cribbin, Wil; Berner, Logan T.; Natali, Susan M.; Goetz, Scott J.; Alexander, Heather D.; Kholodov, Alexander L.

    2016-09-01

    In arctic tundra and boreal forest ecosystems vegetation structural and functional influences on the surface energy balance can strongly influence permafrost soil temperatures. As such, vegetation changes will likely play an important role in permafrost soil carbon dynamics and associated climate feedbacks. Processes that lead to changes in vegetation, such as wildfire or ecosystem responses to rising temperatures, are of critical importance to understanding the impacts of arctic and boreal ecosystems on future climate. Yet these processes vary within and between ecosystems and this variability has not been systematically characterized across the arctic-boreal region. Here we quantify the distribution of vegetation productivity trends, wildfire, and near-surface soil carbon, by vegetation type, across the zones of continuous and discontinuous permafrost. Siberian larch forests contain more than one quarter of permafrost soil carbon in areas of continuous permafrost. We observe pervasive positive trends in vegetation productivity in areas of continuous permafrost, whereas areas underlain by discontinuous permafrost have proportionally less positive productivity trends and an increase in areas exhibiting negative productivity trends. Fire affects a much smaller proportion of the total area and thus a smaller amount of permafrost soil carbon, with the vast majority occurring in deciduous needleleaf forests. Our results indicate that vegetation productivity trends may be linked to permafrost distribution, fire affects a relatively small proportion of permafrost soil carbon, and Siberian larch forests will play a crucial role in the strength of the permafrost carbon climate feedback.

  14. The influence of biological soil crusts on successional vegetation patterns in a revegetated desert area in the Tengger Desert, China

    NASA Astrophysics Data System (ADS)

    Lei, Huang; Zhi-shan, Zhang; Xin-rong, Li

    2014-05-01

    Biological soil crusts (BSCs) are an important cover in arid desert landscapes, and have a profound effect on the soil water redistribution, plant growth and vegetation succession. Although a large number of studies have focused on the single-process of BSCs experimentally, relatively few studies have examined the eco-hydrological mechanisms of BSCs influence on successional vegetation patterns in revegetated desert areas. In this study, based on the long term monitoring and focused research on sand-binding vegetation in the Shapotou region (southeastern edge of the Tengger Desert, China) since the 1950s, the characteristics of plant community and BSCs at different successional stages, and the soil water dynamics were investigated. Then a simplified mathematical model describing the coupled dynamics of soil moisture and vegetation in drylands was developed. And finally the role of BSCs on soil water dynamics and vegetation patterns were discussed. Results have showed that BSCs was closely associated with the vegetation succession, such as in the Caragana korshinskii community, moss crusts were the dominate species and in the Artemisia ordosica community, algae crusts were the dominate species. BSCs had a significant effect on soil water infiltration and it was one of the main driving forces to vegetation pattern formations, as algae crusts would induced the tiger bush stripes and moss crusts would lead to the leopard bush spots in arid ecosystems.

  15. Variations of deep soil moisture under different vegetation types and influencing factors in a watershed of the Loess Plateau, China

    NASA Astrophysics Data System (ADS)

    Fang, Xuening; Zhao, Wenwu; Wang, Lixin; Feng, Qiang; Ding, Jingyi; Liu, Yuanxin; Zhang, Xiao

    2016-08-01

    Soil moisture in deep soil layers is a relatively stable water resource for vegetation growth in the semi-arid Loess Plateau of China. Characterizing the variations in deep soil moisture and its influencing factors at a moderate watershed scale is important to ensure the sustainability of vegetation restoration efforts. In this study, we focus on analyzing the variations and factors that influence the deep soil moisture (DSM) in 80-500 cm soil layers based on a soil moisture survey of the Ansai watershed in Yan'an in Shanxi Province. Our results can be divided into four main findings. (1) At the watershed scale, higher variations in the DSM occurred at 120-140 and 480-500 cm in the vertical direction. At the comparable depths, the variation in the DSM under native vegetation was much lower than that in human-managed vegetation and introduced vegetation. (2) The DSM in native vegetation and human-managed vegetation was significantly higher than that in introduced vegetation, and different degrees of soil desiccation occurred under all the introduced vegetation types. Caragana korshinskii and black locust caused the most serious desiccation. (3) Taking the DSM conditions of native vegetation as a reference, the DSM in this watershed could be divided into three layers: (i) a rainfall transpiration layer (80-220 cm); (ii) a transition layer (220-400 cm); and (iii) a stable layer (400-500 cm). (4) The factors influencing DSM at the watershed scale varied with vegetation types. The main local controls of the DSM variations were the soil particle composition and mean annual rainfall; human agricultural management measures can alter the soil bulk density, which contributes to higher DSM in farmland and apple orchards. The plant growth conditions, planting density, and litter water holding capacity of introduced vegetation showed significant relationships with the DSM. The results of this study are of practical significance for vegetation restoration strategies, especially

  16. Advances in Remote Sensing of Vegetation Merging NDVI, Soil Moisture, and Chlorophyll Fluorescence

    NASA Astrophysics Data System (ADS)

    Tucker, Compton

    2016-04-01

    I will describe an advance in remote sensing of vegetation in the time domain that combines simultaneous measurements of the normalized difference vegetation index, soil moisture, and chlorophyll fluorescence, all from different satellite sensors but acquired for the same areas at the same time step. The different sensor data are MODIS NDVI data from both Terra and Aqua platforms, soil moisture data from SMOS & SMP (aka SMAP but with only the passive radiometer), and chlorophyll fluorescence data from GOME-2. The complementary combination of these data provide important crop yield information for agricultural production estimates at critical phenological times in the growing season, provide a scientific basis to map land degradation, and enable quantitative determination of the end of the growing season in temperate zones.

  17. The applicability of ERTS-1 data covering the major landforms of Kenya. [landforms, vegetation, soils, forests

    NASA Technical Reports Server (NTRS)

    Omino, J. H. O. (Principal Investigator)

    1973-01-01

    The author has identified the following significant results. Five investigators report on the applicability of ERTS-1 data covering the major landforms of Kenya. Deficiencies due to lack of equipment, repetitive coverage and interpretation know-how are also reported on. Revision of lake shorelines is an immediate benefit. Basement system metasediments are rapidly differentiated, but dune areas are not readily distinguishable from sandy soils. Forest, moorland, high altitude grass, tea, and conifer plantations are readily distinguished, with podocarpus forest especially distinguishable from podocarpus/juniperus forest. In the arid areas physiographic features, indicating the major soil types, are readily identified and mapped. Preliminary vegetation type analysis in the Mara Game Reserve indicates that in a typical savannah area about 36% of the vegetation types are distinguishable at a scale of 1:1 million as well as drainage patterns and terrain features.

  18. Interactions between soil moisture and Atmospheric Boundary Layer at the Brazilian savana-type vegetation Cerrado

    NASA Astrophysics Data System (ADS)

    Pinheiro, L. R.; Siqueira, M. B.

    2013-05-01

    Before the large people influx and development of the central part of Brazil in the sixties, due to new capital Brasília, Cerrado, a typical Brazilian savanna-type vegetation, used to occupy about 2 million km2, going all the way from the Amazon tropical forest, in the north of the country, to the edges of what used to be of the Atlantic forest in the southeast. Today, somewhat 50% of this area has given place to agriculture, pasture and managed forests. It is forecasted that, at the current rate of this vegetation displacement, Cerrado will be gone by 2030. Understanding how Cerrado interacts with the atmosphere and how this interaction will be modified with this land-use change is a crucial step towards improving predictions of future climate-change scenarios. Cerrado is a vegetation adapted to a climate characterized by two very distinct seasons, a wet season (Nov-Mar) and dry season (May-Ago), with April and October being transitions between seasons. Typically, based on measurements in a weather station located in Brasilia, 75% of precipitation happens in the wet-season months and only 5% during dry-season. Under these circumstances, it is clear that the vegetation will have to cope with long periods of water stress. In this work we studied using numerical simulations, the interactions between soil-moisture, responsible for the water stress, with the Atmospheric Boundary Layer (ABL). The numerical model comprises of a Soil-Vegetation-Atmosphere model where the biophysical processes are represented with a big-leaf approach. Soil water is estimated with a simple logistic model and with water-stress effects on stomatal conductance are parameterized from local measurements of simultaneous latent-heat fluxes and soil moisture. ABL evolution is calculate with a slab model that considers independently surface and entrainment fluxes of sensible- and latent- heat. Temperature tropospheric lapse-rate is taken from soundings at local airport. Simulations of 30-day dry

  19. Anaerobic Soil Disinfestation (ASD) Combined with Soil Solarization as a Methyl Bromide Alternative: Vegetable Crop Performance and Soil Nutrient Dynamics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil treatment by anaerobic soil disinfestation (ASD) combined with soil solarization can effectively control soilborne plant pathogens and plant-parasitic nematodes in specialty crop production systems. At the same time, research is limited on the impact of soil treatment by ASD + solarization on c...

  20. Heavy metals in vegetables and respective soils irrigated by canal, municipal waste and tube well waters.

    PubMed

    Ismail, Amir; Riaz, Muhammad; Akhtar, Saeed; Ismail, Tariq; Amir, Mamoona; Zafar-ul-Hye, Muhammad

    2014-01-01

    Heavy metal contamination in the food chain is of serious concern due to the potential risks involved. The results of this study revealed the presence of maximum concentration of heavy metals in the canal followed by sewerage and tube well water. Similarly, the vegetables and respective soils irrigated with canal water were found to have higher heavy metal contamination followed by sewerage- and tube-well-watered samples. However, the heavy metal content of vegetables under study was below the limits as set by FAO/WHO, except for lead in canal-water-irrigated spinach (0.59 mg kg(-1)), radish pods (0.44 mg kg(-1)) and bitter gourd (0.33 mg kg(-1)). Estimated daily intakes of heavy metals by the consumption of selected vegetables were found to be well below the maximum limits. However, a complete estimation of daily intake requires the inclusion of other dietary and non-dietary exposure sources of heavy metals.

  1. Effects of rainfall intensity and intermittency on woody vegetation cover and deep soil moisture in dryland ecosystems

    NASA Astrophysics Data System (ADS)

    Zhang, Ding-Hai; Li, Xin-Rong; Zhang, Feng; Zhang, Zhi-Shan; Chen, Yong-Le

    2016-12-01

    Identifying the relationship between the stochastic daily rainfall regime and the dynamics of plants and soil moisture is fundamental for the sustainable management of dryland ecosystems in a context of global climate change. An eco-hydrological model that couples the dynamics of woody vegetation cover and deep soil moisture (typically with a depth interval of 30-150 cm) was used to investigate the effect of stochastic intensity and the intermittency of precipitation on soil moisture in this deep interval, which affects woody vegetation cover. Our results suggest that the precipitation intensity and intermittency play an important role in the dynamics of wood vegetation cover and deep soil moisture. In arid and semiarid regions, as the annual precipitation increased, the rate of woody vegetation cover increased as a power-law function, and the deep soil moisture increased exponentially. For a given annual rainfall, there were positive correlations between the rainfall intensity (or rainfall intermittency) and both the woody vegetation cover and deep soil moisture. The positive correlations between wood vegetation cover and both rainfall intensity and intermittency may decrease with increases in the precipitation intensity or precipitation intermittency. The positive correlations between deep soil moisture and both rainfall intensity and rainfall intermittency increase as the precipitation intensity or precipitation intermittency increases. Moreover, these positive correlations may increase with increases in the mean annual rainfall. Our results emphasize the importance of daily precipitation variations in controlling the responses of woody vegetation cover and deep soil moisture to climate variations in arid and semiarid regions. Our model can aid the understanding of rainfall processes and indicates that increases in rainfall intensity or rainfall intermittency may lead to an increase in woody vegetation cover and deep soil moisture given an invariable annual

  2. Colorimetric Analysis and Spectral Transformation of Soil-Vegetation Mixture Reflectance for Canopy Coverage Estimation

    NASA Astrophysics Data System (ADS)

    Kancheva, R.; Borisova, D.; Mishev, D.

    Vegetation monitoring is one of the essential applications of remote sensing techniques in practice. Concerning agricultural plants an important task is crop state assessment during the growing period. Vegetation status and physiological development are defined by a set of bioparameters such as biomass amount, leaf area index, chlorophyll content, etc. Various methods of spectral data processing are used for their stimulation aiming mainly at the establishment of quantitative relationships between crop biophysical and reflectance properties. Canopy coverage is of a particular interest here because it is an important indicator of plant growth and is closely related with other bioparameters being at the same time a factor of soil-vegetation mixtures reflectance. This paper has the following objectives: - to study the colorimetric characteristics (color coordinates, trichromatic coefficients, excitation purity, dominant wavelength) of different soil types and species as well as their potential for canopy coverage estimation; - to compare and test the correspondence between coverage values evaluated through colorimetric analysis and by using various spectral data transformations (ratio indices, contrasts, normalized differences, linear combinations); - to demonstrate the joint application of both methods for increasing the accuracy and the reliability of canopy coverage assessment. Ground-based reflectance data from peas, spring barley and winter wheat grown on chernozem, alluvial-medow and grey forest soils were gathered. The measurements were performed with a multichannel radiometer in the 400-820 nm spectral band with a 10 nm step. Correlation and regression analysis of plot coverage, color features and spectral indices was carried out. Statistical relationships were derived and used later for canopy coverage estimation on independent data sets. The colorimetric analysis of the reflectance characteristics permited reliable and quite satisfactory coverage evaluations

  3. Soil and vegetation carbon stocks in Brazilian Western Amazonia: relationships and ecological implications for natural landscapes.

    PubMed

    Schaefer, C E G R; do Amaral, E F; de Mendonça, B A F; Oliveira, H; Lani, J L; Costa, L M; Fernandes Filho, E I

    2008-05-01

    The relationships between soils attributes, soil carbon stocks and vegetation carbon stocks are poorly know in Amazonia, even at regional scale. In this paper, we used the large and reliable soil database from Western Amazonia obtained from the RADAMBRASIL project and recent estimates of vegetation biomass to investigate some environmental relationships, quantifying C stocks of intact ecosystem in Western Amazonia. The results allowed separating the western Amazonia into 6 sectors, called pedo-zones: Roraima, Rio Negro Basin, Tertiary Plateaux of the Amazon, Javari-Juruá-Purus lowland, Acre Basin and Rondonia uplands. The highest C stock for the whole soil is observed in the Acre and in the Rio Negro sectors. In the former, this is due to the high nutrient status and high clay activity, whereas in the latter, it is attributed to a downward carbon movement attributed to widespread podzolization and arenization, forming spodic horizons. The youthful nature of shallow soils of the Javari-Juruá-Purus lowlands, associated with high Al, results in a high phytomass C/soil C ratio. A similar trend was observed for the shallow soils from the Roraima and Rondonia highlands. A consistent east-west decline in biomass carbon in the Rio Negro Basin sector is associated with increasing rainfall and higher sand amounts. It is related to lesser C protection and greater C loss of sandy soils, subjected to active chemical leaching and widespread podzolization. Also, these soils possess lower cation exchangeable capacity and lower water retention capacity. Zones where deeply weathered Latosols dominate have a overall pattern of high C sequestration, and greater than the shallower soils from the upper Amazon, west of Madeira and Negro rivers. This was attributed to deeper incorporation of carbon in these clayey and highly pedo-bioturbated soils. The results highlight the urgent need for refining soil data at an appropriate scale for C stocks calculations purposes in Amazonia. There

  4. Contribution of Vegetation to the Microbial Composition of Nearby Outdoor Air

    PubMed Central

    Adams, Rachel I.

    2016-01-01

    ABSTRACT Given that epiphytic microbes are often found in large population sizes on plants, we tested the hypothesis that plants are quantitatively important local sources of airborne microorganisms. The abundance of microbial communities, determined by quantifying bacterial 16S RNA genes and the fungal internal transcribed spacer (ITS) region, in air collected directly above vegetation was 2- to 10-fold higher than that in air collected simultaneously in an adjacent nonvegetated area 50 m upwind. Nonmetric multidimensional scaling revealed that the composition of airborne bacteria in upwind air samples grouped separately from that of downwind air samples, while communities on plants and downwind air could not be distinguished. In contrast, fungal taxa in air samples were more similar to each other than to the fungal epiphytes. A source-tracking algorithm revealed that up to 50% of airborne bacteria in downwind air samples were presumably of local plant origin. The difference in the proportional abundances of a given operational taxonomic unit (OTU) between downwind and upwind air when regressed against the proportional representation of this OTU on the plant yielded a positive slope for both bacteria and fungi, indicating that those taxa that were most abundant on plants proportionally contributed more to downwind air. Epiphytic fungi were less of a determinant of the microbiological distinctiveness of downwind air and upwind air than epiphytic bacteria. Emigration of epiphytic bacteria and, to a lesser extent, fungi, from plants can thus influence the microbial composition of nearby air, a finding that has important implications for surrounding ecosystems, including the built environment into which outdoor air can penetrate. IMPORTANCE This paper addresses the poorly understood role of bacterial and fungal epiphytes, the inhabitants of the aboveground plant parts, in the composition of airborne microbes in outdoor air. It is widely held that epiphytes contribute

  5. Impact of air pollution on vegetation near the Columbia Generating Station - Wisconsin power plant impact study

    SciTech Connect

    Tibbitts, T.W.; Will-Wolf, S.; Karnowsky, D.F.; Olszyk, D.M.

    1982-06-01

    The impact of air pollution from the coal-fired Columbia Generating Station upon vegetation was investigated. Air monitoring of 03 and 02 documented levels that occurred before and with operation of the generating station. Field sampling of alfalfa, lichens, and white pines was undertaken before and after initiation of generating station operations. Controlled environmental exposures were undertaken with separate cultivars of crop species grown in the vicinity of the generating station. Alfalfa, carrots, mint, peas, beans, and trembling aspen were exposed to SO2 and O3 to establish minimum threshold pollutant levels for injury from these pollutants.

  6. The potential for reducing urban air temperatures and energy consumption through vegetative cooling

    SciTech Connect

    Kurn, D.M.; Bretz, S.E.; Huang, B.; Akbari, H.

    1994-05-01

    A network of 23 weather stations was used to detect existing oases in Southern California. Four stations, separated from one another by 15--25 miles (24--40 km), were closely examined. Data were strongly affected by the distance of the stations from the Pacific Ocean. This and other city-scale effects made the network inadequate for detection of urban oases. We also conducted traverse measurements of temperature and humidity in the Whittier Narrows Recreation Area in Los Angeles County on September 8--10, 1993. Near-surface air temperatures over vegetated areas were 1--2{degrees}C lower than background air temperatures. We estimate that vegetation may lower urban temperatures by 1{degrees}C, while the establishment of vegetative canopies may lower local temperatures by an additional 2{degrees}C. An increase in vegetation in residential neighborhoods may reduce peak loads in the Los Angeles area by 0.3 GW, and reduce energy consumption by 0.2 BkWh/year, saving $20 million annually. Large additional savings would result from regional cooling.

  7. Heavy Metals in Soils and Vegetables Irrigated with Urban Grey Waste Water in Fagge, Kano, Nigeria.

    PubMed

    Chiroma, T M; Ebewele, R O; Hymore, F K

    2014-01-01

    There is currently an increased consumption of vegetables within the local urban community. However, contamination of these vegetables with heavy metals poses a potential health hazard. Consequently, the potential contamination problem due to the effect of levels of some heavy metals (Fe, Mg, Zn, Mn, Cu and Cr) in soils and vegetables irrigated with drainage urban grey waste water were investigated. The maximum levels of Fe, Zn, Mn, Cu and Cr in the urban grey waste waters were respectively 2.8, 2.1, 19.5, 2.3 and 143.1 times, higher than the maximum recommended concentrations of these metals: 5.0 μg/mL, 2.0 μg/mL, 0.2 μg/mL, 0.2 μg/mL and 0.1 μg/mL, respectively, for irrigation waters. The soils were found to be contaminated with these metals to levels that range between 24 to 84 percent contaminations. Although the heavy metals concentration ranking in vegetable parts vary with plant specie, the concentrations of Fe, Zn, Mn, Cu and Cr in most parts of the vegetables were above their critical concentrations of 750 - 1000 μg/g, 100 - 400 μg/g, 300 - 500 μg/g, 20 - 100 μg/g and 5 - 30 μg/g, respectively, in plants. This suggests potential toxicity of these parts of vegetables. It was however found that over 40 percent of the concentrations of Fe, Mg, Zn and Cu in Onions, Fe in Okro, Cr in Bushgreen, Cu in Roselle and Zn, Cu in Carrot leaves can be easily removed by washing the leaves with water. However, only Cu concentration in Onions and Bushgreen leaves met the acceptable permissible level in plants after washing.

  8. Sensitivity of Three Vegetation Indices to Cimate and Soil moisture at a Tallgrass Prairie Site

    NASA Astrophysics Data System (ADS)

    Bajgain, R.; Xiao, X.; Wagle, P.; Basara, J. B.

    2014-12-01

    Climatic variability influence vegetation condition and growth, which are often characterized by satellite derived vegetation indices (VIs) such as normalized difference vegetation Index (NDVI), enhanced vegetation Index (EVI) and land surface water index (LSWI). A fourteen-year (2000 - 2013) of NDVI, EVI and LSWI data from Moderate-Resolution Imaging Spectroradiometer (MODIS) were analyzed for assessing grassland vegetation dynamics to climatic variability ( i.e., drought) and soil moisture over the time series at the Marena site, Stillwater Oklahoma,USA. This is also the Marena, Oklahoma In-situ Sensor Testbed (MOISST) site in support of NASA SMAP mission. Change in magnitudes of VIs provided the dynamics of inter-annual variability of the grassland vegetation. The magnitude of VIs declined in dry years (2006 and 2012) .Variation in NDVI and EVI over years resulting from climatic variability was strongly correlated to cumulative seasonal rainfall (NDVI, r = 0.82, EVI, r = 0.77) and average seasonal soil volumetric water content up to 60 cm depth. The EVI declined more than did NDVI during the dry events of 2006 and 2012, indicating that the use of EVI in place of NDVI appears to increase the performance of ecosystem models under drought condition. Furthermore, LSWI was the most sensitive index to drought among the three VIs tested. The LSWI values were negative (LSWI < 0) even within the middle of plant growing season in dry years, showing its potential to track the hydrological status of the ecosystem. Duration of LSWI < 0 in summer was greater in dry years (2006= 53 & 2012= 34 days) compared to wet years (2007 & 2013= 0 days). The result also revealed that LSWI values quantitatively corresponded well with the drought severity categories identified by the United States Drought Monitoring (USDM). In conclusion, the number of days with LSWI < 0 during the plant growing season and LSWI-based drought severity classification scheme can provide useful information for

  9. Feasibility of using LANDSAT images of vegetation cover to estimate effective hydraulic properties of soils

    NASA Technical Reports Server (NTRS)

    Eagleson, P. S.

    1985-01-01

    Research activities conducted from February 1, 1985 to July 31, 1985 and preliminary conclusions regarding research objectives are summarized. The objective is to determine the feasibility of using LANDSAT data to estimate effective hydraulic properties of soils. The general approach is to apply the climatic-climax hypothesis (Ealgeson, 1982) to natural water-limited vegetation systems using canopy cover estimated from LANDSAT data. Natural water-limited systems typically consist of inhomogeneous vegetation canopies interspersed with bare soils. The ground resolution associated with one pixel from LANDSAT MSS (or TM) data is generally greater than the scale of the plant canopy or canopy clusters. Thus a method for resolving percent canopy cover at a subpixel level must be established before the Eagleson hypothesis can be tested. Two formulations are proposed which extend existing methods of analyzing mixed pixels to naturally vegetated landscapes. The first method involves use of the normalized vegetation index. The second approach is a physical model based on radiative transfer principles. Both methods are to be analyzed for their feasibility on selected sites.

  10. Municipal composts reduce the transfer of Cd from soil to vegetables.

    PubMed

    Al Mamun, Shamim; Chanson, Guilhem; Muliadi; Benyas, Ebrahim; Aktar, Munmun; Lehto, Niklas; McDowell, Richard; Cavanagh, Jo; Kellermann, Liv; Clucas, Lynne; Robinson, Brett

    2016-06-01

    Cadmium (Cd) is a non-essential trace element that accumulates in agricultural soils through the application of Cd-rich phosphate fertiliser. Vegetables can accumulate Cd to concentrations that sometimes exceed food safety standards. We investigated the potential of low-cost soil amendments to reduce Cd uptake by spinach (Spinacia oleracea L.), lettuce (Lactuca sativa L.) and onion (Allium cepa L.). Batch sorption experiments revealed the relative sorption of Cd by biosolids, charcoal, lignite, sawdust, two types of compost, bentonite and zeolite. Lignite and compost had the greatest ability to sorb Cd and were subsequently selected for pot trials, which elucidated their effect on Cd uptake by onions, spinach and lettuce in two market garden soils with native Cd concentrations of 1.45 mg/kg and 0.47 mg/kg. The addition of 2.5% (dry w/w) municipal compost reduced the Cd concentration in onions, spinach and lettuce by up to 60% in both soils. The addition of lignite gave variable results, which depended on the soil type and rate of addition. This Cd immobilisation was offset by soil acidification caused by the lignite. The results indicate that municipal compost is a low-cost soil conditioner that is effective in reducing plant Cd uptake.

  11. Gravel admix, vegetation, and soil water interactions in protective barriers: Experimental design, construction, and initial conditions

    SciTech Connect

    Waugh, W.J.

    1989-05-01

    The purpose of this study is to measure the interactive effects of gravel admix and greater precipitation on soil water storage and plant abundance. The study is one of many tasks in the Protective Barrier Development Program for the disposal of Hanford defense waste. A factorial field-plot experiment was set up at the site selected as the borrow area for barrier topsoil. Gravel admix, vegetation, and enhanced precipitation treatments were randomly assigned to the plots using a split-split plot design structure. Changes in soil water storage and plant cover were monitored using neutron probe and point intercept methods, respectively. The first-year results suggest that water extraction by plants will offset gravel-caused increases in soil water storage. Near-surface soil water contents were much lower in graveled plots with plants than in nongraveled plots without plants. Large inherent variability in deep soil water storage masked any effects gravel may have had on water content below the root zone. In the future, this source of variation will be removed by differencing monthly data series and testing for changes in soil water storage. Tests of the effects of greater precipitation on soil water storage were inconclusive. A telling test will be possible in the spring of 1988, following the first wet season during which normal precipitation is doubled. 26 refs., 9 figs., 9 tabs.

  12. Remote Sensing of Soil Moisture based on Dynamic Vegetation Scattering Properties for AMSR sensors

    NASA Astrophysics Data System (ADS)

    Du, J.; Kimball, J. S.; Jones, L. A.

    2015-12-01

    Accurate mapping of soil moisture and its spatial-temporal variations are of great significance to scientific studies on global water, energy and carbon cycles as well as operational applications including flood and drought monitoring, water resources management and crop yield forecasts. An approach for deriving volumetric soil moisture using satellite passive microwave radiometry from the Advanced Microwave Scanning Radiometers AMSR-E and AMSR2 was developed in this study. The algorithm adopts a weighted averaging strategy for soil moisture estimation based on a dynamic selection of empirically determined vegetation single-scatter albedo values. The resulting soil moisture retrievals demonstrate more realistic global patterns and seasonal dynamics relative to the baseline University of Montana (UMT) soil moisture product. Quantitative analysis of the new approach against in situ soil moisture measurements over four global study regions also indicates significant improvement over the baseline algorithm, with coefficients of determination (R2) between the retrievals and in-situ measurements increasing by approximately 16.9% and 41.5% respectively; and bias-corrected RMSEs decreasing by about 25.0% and 38.2% for respective ascending and descending orbital data records. Initial comparisons between soil moisture retrievals from AMSR2 and SMAP indicate coherent global and seasonal patterns.

  13. Accumulation of heavy metals in dietary vegetables and cultivated soil horizon in organic farming system in relation to atmospheric deposition in a seasonally dry tropical region of India.

    PubMed

    Pandey, J; Pandey, Usha

    2009-01-01

    Increasing consciousness about future sustainable agriculture and hazard free food production has lead organic farming to be a globally emerging alternative farm practice. We investigated the accumulation of air-borne heavy metals in edible parts of vegetables and in cultivated soil horizon in organic farming system in a low rain fall tropical region of India. The factorial design of whole experiment consisted of six vegetable crops (tomato, egg plant, spinach, amaranthus, carrot and radish) x two treatments (organic farming in open field and organic farming in glasshouse (OFG)) x seven independent harvest of each crop. The results indicated that except for Pb, atmospheric deposition of heavy metals increased consistently on time scale. Concentrations of heavy metals in cultivated soil horizon and in edible parts of open field grown vegetables increased over time and were significantly higher than those recorded in OFG plots. Increased contents of heavy metals in open field altered soil porosity, bulk density, water holding capacity, microbial biomass carbon, substrate-induced respiration, alkaline phosphatase and fluorescein diacetate hydrolytic activities. Vegetable concentrations of heavy metal appeared in the order Zn > Pb > Cu > Ni > Cd and were maximum in leaves (spinach and amaranths) followed by fruits (tomato and egg plant) and minimum in roots (carrot and radish). Multiple regression analysis indicated that the major contribution of most heavy metals to vegetable leaves was from atmosphere. For roots however, soil appeared to be equally important. The study suggests that if the present trend of atmospheric deposition is continued, it will lead to a destabilizing effect on this sustainable agricultural practice and will increase the dietary intake of toxic metals.

  14. Sensing soil moisture and vegetation using GNSS-R polarimetric measurement

    NASA Astrophysics Data System (ADS)

    Jia, Yan; Savi, Patrizia

    2017-02-01

    GNSS-Reflectometry is an efficient tool for remote sensing and plays a key role in several applications. The estimation of soil moisture and vegetation in the land field is attracting widespread interest in hydrology, climatology and carbon cycles. In order to investigate the scattering polarization properties from different types of surface environments, an airborne measurement was performed, equipped with a new 4-channel prototype for collecting the direct, reflected left-hand circular polarization (LHCP) and right-hand circular polarization (RHCP) signals. Both the reflected LHCP and RHCP signals were acquired at the same time by a dual polarization antenna. A data averaging procedure was used to reduce the incoherent part of the received power and two reflected signals were normalized by direct signals obtained from each front-end (FE). Then three polarimetric observables were used to analyze vegetation biomass and soil moisture fluctuations. It was concluded that the polarimetric ratio (PR) is sensitive to soil moisture content (SMC) and considerably independent of roughness and vegetation biomass. The trunk component is confirmed to be the most important factor affecting the amplitude of scattering polarizations. Furthermore, the measurement results showed that the PR variation between different elevation angles was affected by roughness and biomass. The PR variation in forests with big biomass shows the least amount of changes when compared to other geographical environments. The results show another possibility of further geophysical parameter evaluations employing polarimetric applications in GNSS-R.

  15. Lead and cadmium in soils and vegetables from urban gardens of Salamanca (Spain).

    PubMed

    Sánchez-Camazano, M; Sánchez-Martín, M J; Lorenzo, L F

    1994-05-23

    The Pb and Cd contents of soils and vegetables from 16 urban gardens of Salamanca (Spain) have been determined. The metals were found to occur at concentrations in the ranges 20.1-96.2 and 0.20-0.95 microgram/g for Pb and Cd, respectively. The mean Pb concentration found was 2.60 times higher than that in natural soils of the Salamanca province, whereas that of Cd exceeded its mean concentration in natural and cultivated soils by a factor of 2.73 and 2.04, respectively. The Pb and Cd contents of the vegetables (branches) ranged between 4.17 and The Pb and Cd contents of the vegetables (branches) ranged between 4.17 and 52.7 micrograms/g, and between 0.35 and 3.05 micrograms/g, respectively. According to these results, Pb and Cd occur at pollution levels in the surveyed gardens. The total and soluble Pb (extractable with 1 N ammonium acetate) levels were found to be related to the traffic density. On the other hand, the Cd levels appear to be more closely related to the distance from roadways, as well as to the age of the garden and the flow of visitors.

  16. [Variation of soil organic carbon under different vegetation types in Karst Mountain areas of Guizhou Province, southwest China].

    PubMed

    Liao, Hong-kai; Long, Jian

    2011-09-01

    This paper studied the variation characteristics of soil organic carbon (SOC) and different particle sizes soil particulate organic carbon (POC) in normal soil and in micro-habitats under different vegetation types in typical Karst mountain areas of southwest Guizhou. Under different vegetation types, the SOC content in normal soil and in micro-habitats was all in the order of bare land < grass < shrub < forest, with the variation range being 7.18-43.42 g x kg(-1) in normal soil and being 6.62-46.47 g x kg(-1) and 9.01-52.07 g x kg(-1) in earth surface and stone pit, respectively. The POC/MOC (mineral-associated organic carbon) ratio under different vegetation types was in the order of bare land < grass < forest < shrub. Under the same vegetation types, the POC/MOC in stone pit was the highest, as compared to that in normal soil and in earth surface. In the process of bare land-grass-shrub-forest, the contents of different particle sizes soil POC increased, while the SOC mainly existed in the forms of sand- and silt organic carbon, indicating that in Karst region, soil carbon sequestration and SOC stability were weak, soil was easily subjected to outside interference and led to organic carbon running off, and thus, soil quality had the risk of decline or degradation.

  17. Bioindication of air pollution effects near a copper smelter in Brazil using mango trees and soil microbiological properties.

    PubMed

    Klumpp, Andreas; Hintemann, Therese; Lima, Josanídia Santana; Kandeler, Ellen

    2003-01-01

    A field study near the copper smelter of a large industrial complex examined air pollution effects on vegetation and soil parameters in Camaçari (northeast Brazil). Close to the smelter, soil pH-value was lower and total acidity as well as organic carbon contents were higher compared with a site far from the source and two reference sites. The acidification of top soil particularly and the drastically enhanced plant-available copper concentrations were caused by atmospheric deposition. High sulphur and copper deposition significantly reduced microbial biomass and altered functional diversity of soil microorganisms (arylsulphatase and xylanase). Large accumulations of sulphur, arsenic and copper were detected in mango leaves (Mangifera indica) growing downwind from the smelter suggesting potential food chain-mediated risk.

  18. Soil bacterial community shifts in response to vegetation and soil temperature change in moist acidic tundra of Northern Alaska

    NASA Astrophysics Data System (ADS)

    Ricketts, M. P.; Gonzalez-Meler, M. A.

    2013-12-01

    The effects of rising temperatures on Earth's ecosystems remain largely unknown and are an active area of research. In temperate systems, plant species often respond directly to climate forcing factors causing complex cascading effects in ecosystem C and nutrient cycling. Similarly, in the Arctic tundra, shifts in aboveground species composition and distribution have been observed in response to warming and other climate change factors, following increases in active layer depth and soil temperature. These abiotic changes provide soil microorganisms access to previously unavailable soil organic matter via thawing soils and increases soil microbial mineralization rates, suggesting that soil microorganisms may be eliciting the plant response. It is hypothesized that this release of nutrients may be providing a competitive advantage to N rich woody species, such as dwarf birch and diamond-leaf willow, over grassy species such as cottongrass tussock. Here we examine how microbial communities respond to i