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United States Department of Agriculture

Agricultural Research Service

2010 Annual Report

3.Progress Report

Sustaining the Earth's Watersheds Agricultural Research Data System (STEWARDS) web site was made available to the public. Currently, it is populated with data from 13 ARS benchmark watersheds, comprising more than 500 individual measurement sites of up to 35 years of records, totaling well in excess of 10M geospatially and temporally documented data records and comprehensive metadata. Soil quality assessments on the CEAP Cropland sites are progressing very well. Samples have been collected from 13 of the original 14 CEAP Cropland Watershed sites. They have also been collected from a transitional organic farm in New Hampshire (sampled in lieu of the Town Brook Watershed in NY), the NRCS CEAP Special Emphasis Watershed site in Puerto Rico, and the NRCS Chaney Lake watershed in Kansas. Texture, bulk density, water stable aggregation, microbial biomass carbon, acidity (pH), electrical conductivity (EC), total organic carbon and N, nitrate and ammonium N, Mehlich extractable P, K, Ca, and Mg, diethylene triamine pentaacetic acid (DTPA) extractable micronutrient levels, and beta-glucosidase analyses for all samples are projected to be completed by the end of 2010. Data analysis is progressing using appropriate statistical approaches for comparisons at each watershed location. Measured data, scored values after entering the data into the Soil Management Assessment Framework (SMAF) and overall soil quality index (SQI) values based on the average of all SMAF scored indicators are being examined. To complete the initial Cropland CEAP soil quality assessment, samples collected from the Mahantango creek watershed in Pennsylvania during November 2010, will be analyzed in FY11. The CEAP Ecology Working Group developed five guiding principles that will lead to hypothesis driven sampling protocols capable of documenting habitat and biological responses to conservation practices within wadeable streams. The guiding principles were recently published within the Journal of American Water Resources Association. ARS researchers at Kimberly, Idaho, calibrated the modified universal soil loss equation for furrow irrigated fields. This will allow water quality models like SWAT or APEX to be used in irrigated watersheds. Beasley Lake water quality continues to be monitored for water quality and ecology. Fish stocks were assessed in late 2009. To improve lake water quality by trapping sediments, an NRCS-funded sediment retention basin was constructed in 2010. In one ~750 ac Indiana watershed, CEAP scientists worked with local SWCD and farmers to replace all surface tile risers with blind inlets and added equipment to monitor sediment losses. This project has resulted in the adaptation of this technology to be included for cost share as an NRCS CP 690 in the eFOTG for Indiana. Research from the CEAP project has been used to inform the NRCS Mississippi River Basin Initiative Projects in Ohio, Indiana, Iowa, Missouri, and Mississippi, both in prioritizing targeted watersheds, and in supporting with ARS data for individual MRBI projects in some states. CEAP researchers are working with NRCS and project staffs on monitoring protocols for the 2010 projects.

1. Columbus, Ohio: Documented public health risks posed by channelized headwater streams. Public health issues related to channelized headwater streams that are common throughout the midwestern United States have not been explored. ARS scientists from Columbus, Ohio documented the public health risks posed by channelized headwater streams by comparing water chemistry and the larval abundances of potential insect disease vectors between channelized and unchannelized headwater streams within central Ohio. Concentrations of commonly occurring nutrients and pesticides was often greater in channelized headwater streams and exceeded national drinking water standards more often. Potential insect vectors of the West Nile virus, Lacrosse encephalitis, St. Louis encephalitis, and Eastern Equine encephalitis constituted a small fraction of the overall larval insect captures and abundances did not differ between stream types. These results suggest that management of channelized headwater streams may be necessary to reduce the public health risks related to the downstream transport of agricultural nutrients and pesticides. Specifically, agricultural conservation practices capable of reducing nutrient and pesticide loads within channelized headwater streams may assist with the protection of downstream surface drinking water sources. These results also suggest headwater streams in general may not serve as a significant source of potential disease vectors and insecticide application and channelizing these streams for larval mosquito control does not appear to be warranted.

2. Determined the feasibility of an end-of-tile filter approach to reduce nutrient and pesticide transport via subsurface drainage. Subsurface drainage is a necessity for crop production agriculture in humid climates with poorly drained soils. In excess of 20.6 million ha (37%) of the tillable acres in the Midwest are managed with subsurface tile. While partially responsible for consistent high crop production yields, subsurface tile drainage has been recognized as a primary source of agricultural nutrient transport to streams and waterbodies to which they discharge. ARS scientists in cooperation with United States Golf Association (USGA) personnel investigated the feasibility of an end-of-tile filter for treating subsurface drainage waters. The findings suggest that the end-of-tile filter approach could be adapted as a best management practice to reduce nutrient and pesticide transport in subsurface tile drainage where the contributing area and flow rates are relatively small. Additionally, the findings support further investigation into alternative sorbent materials and delivery designs that permit larger drainage areas and greater flow rates to be filtered. The beneficiaries of this research are all downstream water users that use surface water for drinking, recreation, and navigation.

3. Developed baseline water quality signatures from various landscapes (urban, agriculture, turf) within an urban to rural gradient. Significant amounts of agricultural lands within the Upper Big Walnut Creek (UBWC) watershed are being lost annually to urban development. Understanding the role of each landuse within the watershed is critical to the development, placement, and assessment of best management practices (BMPs) aimed at reducing and mitigating nonpoint source pollution. ARS scientists in cooperation with Soil Water Conservation District and NRCS personnel and UBWC landowners and operators measured water quality signatures from different landuses. Within the UBWC watershed, datasets have been assembled for agriculture, urban, and turf landscape classifications. The results suggest that nitrogen is primarily a result of agricultural activities; however, phosphorus contributions are more evenly distributed from across landuses. These datasets will provide state, federal, and private entities a “measuring stick” for assessing the impacts of implementing BMPs across the watershed.

4. Examined influence of riparian habitat type on aquatic community colonization. Previous studies have not examined aquatic community colonization within riparian zones of agricultural headwater streams. Understanding how aquatic community colonization differs between channelized and unchannelized streams is needed to assist with developing riparian management guidelines for these small streams. An ARS scientist and student intern from the Ohio State University evaluated if aquatic community colonization within riparian zones of headwater agricultural streams is influenced by stream channelization. Macroinvertebrate abundance, taxa richness, and relative abundances of mosquitoes, dipterans, and crustaceans were greater within experimental mesocosms placed in the riparian zones of unchannelized headwater streams than channelized headwater streams. These results suggest stream channelization reduces aquatic community diversity and abundance in riparian zones of headwater agricultural streams. This information can be used by state, federal, and private agencies responsible for managing agricultural watersheds and restoring streams.

5. El Reno, Oklahoma: Spatial resolution of input data sets may impact Soil and Water Assessment Tool (SWAT) performance. The level of uncertainty of input parameters in hydrologic models has a significant impact on model simulation accuracy and the uncertainty of the resulting model outputs. Two separate studies were conducted in the Fort Cobb Reservoir watershed, located in southwestern Oklahoma, to evaluate the impact of spatial resolution of precipitation and soils data sets on SWAT parameters and simulation accuracy. The study findings indicated that varying precipitation data set input resolution impacted some SWAT calibration parameters at both the daily and monthly time scales, but only affected model performance at the daily time scale. Varying the input resolution of the soils input data set had less impact on model parameters and model performance. Precipitation input spatial resolution could impact the value of certain model parameters used to evaluate the effectiveness of some conservation practices, so caution is urged.

6. Tifton, Georgia: Assessment of Conservation Practice Approaches in the Little River Watershed. USDA has been tasked to determine the effectiveness of federally funded conservation programs. We used the SWAT model to simulate the water quality effect of upland conservation practices (CPs) commonly adopted in the Little River Experimental Watershed (LREW) for either erosion or nutrient control and compared those results to the simulated impact of the riparian forest buffers currently in the LREW. Erosion CPs resulted in the greatest reductions in sediment and phosphorus while nutrient reduction practices were most effective in reducing total stream nitrogen. We also evaluated three different prioritization scenarios for implementing. Prioritizing based upon nonpoint source pollutant load yielded more efficient water quality improvements while the other implementation schemes were less efficient. Riparian forest buffers offered the most comprehensive reduction of all three pollutants. Simulation results indicate that the current level of riparian forest cover in the LREW may be the single greatest contributor to nonpoint source pollutant reduction.

7. Assessment of Conservation Practice Approaches in the Jobos Bay Watershed. Groundwater and surface runoff samples collected from February 2008 through December 2009 from an intensively managed agricultural field within the Jobos Bay Watershed were analyzed for nutrient and pesticide concentrations. Nitrate concentrations in the monitoring wells located across the cultivated field ranged from non detectable to 11.40 mg L-1. Nitrate concentrations were consistently highest in monitoring wells located north of the cultivated fields and decreased downslope, indicating minimal impact on nitrate concentrations due to the studied agricultural field. Seasonal nitrate concentrations in riparian wells downslope from the cultivated field were much less than those observed upgradient. Maximum observed groundwater concentrations for atrazine plus its degradates were 0.03 ug L-1 upgradient of the field, 22 ug L-1 within the field, and 0.17 ug L-1 downgradient from the field. These pesticide concentrations indicate significant transport from the field surface to the groundwater within the confines of the agricultural field. The current EPA maximum contaminant level (MCL) drinking water standard for this compound and its degradates is 3 ug L-1. Surface runoff samples collected from field drainage indicated significant loss of pesticides due to surface runoff and transport.

8. Oxford, Mississippi (Beasley Lake): Documented long-term improvement in Mississippi Delta lake water quality caused by conservation practice implementation. Fifteen years ago, Beasley Lake was a sediment-damaged oxbow lake with poor water quality and fisheries. The watershed was subjected to a variety of conservation practices with the goal of improving the lake water quality. This research indicates that as conservation practices were implemented within the watershed, water quality continued to improve, as measured by decreases in nutrients and sediments. The latest analyses indicate that nutrient concentrations continue to decline over time and have not yet reached their lowest levels. While showing little initial improvement, fish stocks improved dramatically after conservation practices (particularly CRP) were more broadly incorporated within the watershed and water quality improved. Most recently, the numbers of bluegill have declined slightly as largemouth bass have increased in both number and size indicating a need to harvest bass from the system.

9. Oxford, Mississippi (Goodwin Creek and Little Topashaw Canal): Tillage significantly affects ephemeral gully erosion. Ephemeral gully erosion has been shown to be a significant source of sediment from many agricultural fields as a result of soil disturbing tillage operations. The important processes that influence ephemeral gully erosion have been incorporated into the USDA Annualized Agricultural Non-Point Source pollution model (AnnAGNPS) by utilizing procedures developed from basic laboratory research studies. Evaluations of agricultural practices have been performed using AnnAGNPS in watersheds throughout the United States as part of the USDA Conservation Evaluation and Assessment Project (CEAP) as well as watersheds in Spain, Italy and China for their effect on sediment delivered from sheet and rill erosion, as well as from ephemeral gully erosion. This provides an important tool for action agencies, such as the USDA-Natural Resources Conservation Service, to evaluate the effect of agricultural conservation practices at field or watershed scales and implement cost effective conservation programs targeted to the most appropriate sources of sediment. (A. Effectiveness of Conservation Practices)

10. Soil erosion by water shown to remain a major problem in many regions of the U.S. Estimates by the USDA suggest that ephemeral gully erosion ranges from 18 to 73% of the total erosion. Refilling or removing ephemeral gullies by tillage causes high erosion rates to continue damaging the soil next to the gully. The impact of filling ephemeral gullies on crop yield and the health or quality of the soil adjacent to gullies was measured on two gullies in Topashaw Canal Watershed, Mississippi, two gullies in Cheney Lake watershed, KS and two gullies in the Black Soils region of NE China. Soil physical, chemical, and biological indicators of soil quality were measured along transects perpendicular to the gullies and at background locations representing natural conditions. This dataset is being used to determine the best indicators of soil quality and the impact of ephemeral gully erosion on soil quality. This information is important when implementing conservation practices by action agencies when controlling ephemeral gully erosion. (E. Watershed Management, Water Availability, and Ecosystem Restoration).

11. Ames, Iowa: Denitrifying bioreactors - an approach for reducing nitrate loads in stream waters. Low-cost and simple technologies are needed to reduce export of excess nitrogen in subsurface drainage water to sensitive aquatic ecosystems. Denitrifying bioreactors are an approach where solid carbon substrates are added into the flow path of contaminated water. ARS scientists in Ames, Iowa, summarized design alternatives for bioreactors, their effectiveness, and factors limiting performance. Two common designs have proven successful in field settings, with nitrate removal rates ranging up to 22.0 g N m-3 day-1, depending on the type of design, rate of water flow, and incoming nitrate concentration. Additionally, bioreactors may reduce transport of veterinary antibiotics (sulfamethazine, enrofloxacin) applied to soil in manure, and transport of the herbicide atrazine, commonly applied to corn, without affecting denitrification rates. Denitrifying bioreactors are cost effective and complementary to other practices that can decrease nitrate loads to surface waters. This information will be of use to farmers and state and federal action agencies in setting priorities for the expenditure of conservation monies to improve surface waters affected by excess nitrate.

12. Potential water quality impact of drainage water management in the Midwest USA. Drainage water management (DWM) is a promising technology for reducing nitrate losses from artificially drained (or “tiled”) fields. While there is an extensive history for the practice in North Carolina, little is known about the efficacy or cost effectiveness of the practice under Midwest conditions where artificial drainage is widely used. ARS scientists in Ames, Iowa, used soil and land cover databases with modeling to estimate that 4.8 million ha of land used to grow corn within the Midwest would be suitable for DWM, potentially reducing nitrate loss by approximately 83,000 metric tons (91,300 tons) per year. Considering the cost of control structures, redesign of new drainage systems, and payments to farmers to adjust the control structures to reduce nitrate losses, the cost per kg of nitrate reduced in drainage water for DWM was estimated at $2.71 ($1.23/lb). This information will be of use to farmers and state and federal action agencies in setting priorities for the expenditure of conservation monies to improve surface water quality.

13. Potential water quality impact of cover crop use in corn-soybean rotations in the Midwest. Cover crops are a promising management practice for reducing nitrate losses from agricultural fields in the Midwest, because they in effect lengthen the growing season with living plants in fields with a corn-soybean rotation. Oat and rye cover crops are potential cover crops for the Midwest because they grow well in cool weather. Oat does not overwinter, whereas rye is extremely winter-hardy and overwinters easily. Over four years an oat cover crop reduced nitrate losses in tile drainage by 39% and the rye cover crop reduced it by 48%. Additionally, cover crops have the potential to increase soil carbon and improve long-term soil productivity. This information will be of use to farmers and state and federal action agencies in setting priorities for the expenditure of conservation monies to improve surface water quality.

14. Improving nitrogen (N) management using simulation models. N fertilizer rates determined using the Late Spring Nitrate Test (LSNT) differ each year because variable spring weather influences the amount of soil N available to the crop. Previous work showed the LSNT was effective in reducing nitrate losses, but adoption of this practice is limited because of the time requirement for soil sampling and fertilizer application. ARS researchers in Ames, Iowa, used the ARS Root Zone Water Quality Model (RZWQM) to simulate how weather impacts nitrogen in the soil profile and subsequent N fertilizer rates. The model simulated lower nitrate leached when the Late Spring Nitrate Test was used to determine N application rates, compared to fall N fertilizer applications, as observed in a paired watershed study. Early season precipitation and temperature accounted for 90% of the yearly variation in spring N requirements. This research will help us better understand how weather patterns should be considered in managing nitrogen. This will help us develop simple tools to optimize N fertilizer recommendations with less reliance on soil sampling and analysis that can delay critical crop-management decisions. This would benefit producers by making it easier for farmers to adopt this effective conservation practice.

15. Persistence and leaching of the veterinary antibiotic sulfamethazine in soil evaluated in laboratory studies. Degradation occurred in two phases and was described using an availability adjusted first-order model. Under anerobic conditions sulfamethazine was more persistent than under aerobic conditions. The formation of soil-bound (non-extractable) residues was the primary mechanism of sulfamethazine removal from soil. Leaching studies showed that sulfamethazine is highly mobile in soil. This information is of interest to the public and policy makers who need to understand how antibiotics applied to soil in manure may affect water quality and aquatic ecosystems.

16. Improving landscape scale descriptions of soil water variability and movement using topographic data. Crop growth often depends on water supplied to the soil from shallow groundwater, through a process commonly called sub-irrigation. However, in glacial landscapes with "pothole" depressions, this water source becomes variable spatially and difficult to predict. Water table depths depend on place in the landscape and time of year. The water table is roughly parallel with the soil surface after spring snowmelt, but not during the growing season when the water table gradients are reduced and are influenced by the positioning of subsurface drains. Scientists in Ames Iowa found upland positions have the greatest variation in water table depth, whereas lower sites dominated by tile drains have less variation. These descriptions will help scientists estimate groundwater recharge following rainfall, and how much groundwater is taken up to replenish growing crops. This information, obtained using a novel technology to monitor soil water storage and movement, is of interest to scientists who want to describe soil water patterns and better understand crop water use and potential leaching of nutrients and agricultural chemicals at the landscape scale.

17. Groundwater quality during conversion of cropland to a prairie reconstruction. How would water quality change if agricultural land were converted back to native prairie? Opportunities to answer this question rarely occur. ARS scientists in Ames, Iowa, tracked nitrate and phosphorus (P) in groundwater during establishment of tall-grass prairie vegetation. We found nitrate and P contrasted one another. Nitrate decreased within three years, when the prairie first became well established. Thereafter, nitrate was seldom detected in shallow groundwater beneath low-lying drainageways. In groundwater beneath higher parts of the landscape nitrate took three years to begin to decrease, but did not fully diminish, and averaged 2 ppm nitrate-N after five years. The landscape differences resulted from greater amounts of leachable N in upland subsoils. Phosphorus showed a different story, and did not change with time during the study. The largest P concentrations in groundwater occurred in low-lying positions, where sediments were deposited that resulted from upslope soil erosion under past tillage. These transported topsoils provide a source of P, and shallow groundwater conditions in these areas help make this P more mobile. P concentrations in these drainageways indicated risk to surface water quality, especially when shallow groundwater rises to the surface and contributes to runoff. The conclusion that in-field deposition of eroded soil can pose a long-term risk for water quality is of concern to stakeholders with interests in agricultural water quality and ecosystem restoration.

18. Managing soils as a part of urban construction projects. During urban construction, topsoil is removed, subsoil is compacted, and only a thin layer of topsoil is returned to the site. Compaction results in poor growth of lawns and trees, increased runoff of nutrients and pesticides, and increased soil erosion. ARS scientists in Ames, Iowa, showed that compost combined with prairie grasses improved water holding capacity and reduced soil erosion compared with a control lawn site. While runoff was not measurably decreased in this short-term experiment, increased water storage should be of long term benefit for restoring the hydrologic functioning of soils disturbed by urban development. This information is of interest to urban planners who desire to remediate urban soil after construction projects are done.

19. West Lafayette, Indiana: Evaluation of Conservation Reserve Program on Phosphorus Loading and NEXRAD Precipitation as Input for SWAT Modeling. This study assessed the impacts of conservation buffers and grasslands on discharge and Total Phosphorus (TP) loads using the SWAT model with a land cover data developed from an Object-Based Image Analysis (OBIA) along with different precipitation datasets from the National Climatic Data Center (NCDC), the National Soil Erosion Research Laboratory (NSERL), the Next-Generation Radar (NEXRAD), and adjustment of the NEXRAD (NEXRAD-Adjusted) in the St. Joseph River Watershed (SJRW) and the Cedar Creek Watershed (CCW) in northeast Indiana. The objectives of this study were:.
1)to develop a method to identify vegetated buffers and conservation grasslands using object-based image analysis with high resolution ortho-rectified aerial photography and Landsat satellite imagery; and.
2)to assess the impacts of vegetated buffers and conservation grasslands on water quality using the Soil and Water Assessment Tool hydrologic nonpoint source model (SWAT) along with different precipitation datasets. This research provided a better means of monitoring existing programs and developing more effective management strategies that can considerably reduce nutrient inputs into water systems. Because the OBIA rules can be applied to different acquisition date of imagery, it should help policy makers and natural resource managers to rapidly quantify areas under the vegetative buffers and conservation grasslands or other similar conservation practices. This information can then be used to assess their impact on the environment.

20. Plot-Scale Research Can Provide Useful Information About Field-Scale Phosphorus Losses. There has been a tremendous amount of research in recent years to determine how management at the field level will impact water quality. The vast majority of this research has been conducted at the plot (i.e. approximately 20 sq ft) scale. We conducted this research to determine if plot scale research could be used to determine differences in phosphorus transport from fields that were managed differently. Soluble phosphorus and total phosphorus losses were generally "directionally" correct, meaning that plots that had greater phosphorus losses were located in the fields with greater phosphorus losses. The impact of this research is that it appears to validate the use of plot scale data to evaluate how management practices affect phosphorus transport at the field scale.

21. Ditch Dredging Not as Detrimental to Water Quality as Originally Thought. In many areas of the country, drainage ditches are necessary for agriculture to exist, otherwise, the fields would be too wet to support the crops. In areas where the soils or ditch banks are erodible, sediment buildup requires that dredging occur every 5 to 10 years. Our previous research has shown that immediately after dredging, nutrient transport is much greater in the ditches than prior to dredging. In this study, we examined six years (2003 " 2008) of intensive water quality samples on two agricultural drainage ditches. During this period, one of the ditches had two dredging operations. Using this dataset, we observed removal of nutrients from the water during the 12 months following the dredging (207 lb of NH4-N removed; 14.5 lb of soluble phosphorus removed; and 12 lb of total phosphorus removed). The removal of nutrients from the water resulted in better water quality conveyed to downstream water bodies when considering either the entire year after dredging, or the individual months " up to 12 months after the dredging activity. We attribute this improvement in water quality to:.
1)an improvement in the physicochemical status of the sediments after being exposed,.
2)"fresh" sediments that were deposited in the ditch bed after dredging,.
3)regrowth and recolonization by the algae and plants, and.
4)formation of microbial biofilms on sediments and rocks in the ditch bed. To avoid the detrimental impacts on water quality immediately after dredging, and to maximize the benefit of ditch recovery, we propose that ditch managers work with agricultural producers to delay nutrient applications to adjacent fields for at least one month after dredging activities. This should allow the ditches sufficient time to recover their ecological function following dredging.

22. Blind Inlet Implemented as Best Management Practice for Draining Pot-Holes at the Watershed Scale. Isolated pot-holes are a common landscape feature throughout much of the Midwestern United States. While these areas were generally wetlands before settlement, if an isolated pot-hole is located in a field that is farmed, it is generally drained using surface inlets. A surface inlet is generally a pipe that acts as a conduit for water and associated contaminants directly to the agricultural drainage ditch, which may be several miles away. Previous research has shown that these areas are large contributors to contaminants in agricultural drainage ditches. An alternative is to use a blind inlet, also known as a French drain, to drain the surface water from these isolated potholes. Our research has demonstrated that blind inlets can reduce sediment losses from these fields by as much as two thirds compared to what would be expected if tile inlets were used. With up to several hundred acres of isolated pot-holes contributing water and contaminants to a single agricultural drainage ditch, such a reduction in sediment loss could result in a significant improvement in water quality. Furthermore, the reduction in sediment loads to the drainage ditches could reduce maintenance costs, such as those associated with dredging activities that are required when sediments build up in agriculture drainage ditches and limit the flow of water away from the agricultural fields. Field scale testing of this technology through this project led to cooperating with the DeKalb County SWCS and local farmers to replace all tile risers in a medium size (~750 ac) monitored watershed with blind inlets. This was completed in April 2010. We will complete our first full field season of testing this technology at the watershed scale in November 2010.

23. Beltsville, Maryland:Use of NEXRAD Improves Streams Flow Calibrations in SWAT Model: A Better Precipitation Data-Source for Accurate Water Balance in Watershed Models. Hydrologic and water quality models are very sensitive to input parameter values, especially precipitation input data. We compared several sources of rainfall data with the next generation radar (NEXRAD) rainfall data to examine the impact of such sources on SWAT model streamflow calibrations for a watershed located in the coastal plain of Maryland. Model simulation results indicated that distance and location of the rain gauges located outside the watershed boundary have a significant impact in simulating hydrologic and water quality response of the watershed. In the absence of a spatially representative network of rain gauges within the watershed, NEXRAD data produced more accurate estimates of streamflow than using single gage data. This study concludes that one has to be mindful of the source and methods of interpolation of rainfall data for input into hydrologic and water quality models if high–quality simulations are desired.

24. Geospatial Tools for Conservation Effects Assessment in the Chesapeake Bay Region. Choptank River Conservation Effects Assessment Project has completed five years of field work to support the development and implementation of geospatial adaptive management tools for cover crop management. Developed in collaboration with United States Geologic Survey and the Maryland Department of Agriculture, the tools combine field-specific conservation program enrollment data with satellite imagery analysis for rapid quantification, verification and certification of cover crop performance. Now that the methodologies have been successfully developed, Maryland is currently beta-testing technology transfer of the geospatial cover crop management toolkits at the Talbot County, Maryland Soil Conservation District. Part of our strategy is to automate the aggregation of the analytical output (site-specific conservation program performance data) to match watershed and county boundaries, so as to provide useful, rapid appraisal of cover crop success in protecting water quality, while also maintaining farm data privacy as required in Section 1619 of the Farm Bill. By continuing the work conducted in collaboration among the Maryland Department of Agriculture, the United States Department of Agriculture, the United States Geologic Survey, the National Fish and Wildlife Agency, and other partners, we hope to substantially improve the effectiveness of winter cover crop nutrient uptake in the Chesapeake Bay Region.

25. Ft. Collins, Colorado: Release of Object Modeling System (OMS) Version 3.0. ARS scientists and collaborators at Fort Collins, Colorado released OMS3 as a new framework for computer model development and broad application. OMS3 provides an open-source approach for object- and component-based modeling, and contains multi-threading capability for high performance computing on multi-CPU desktops (in particular for complex spatially-distributed models). OMS3 also supports Natural Resources Conservation Service (NRCS) infrastructure for information technology and the use of existing model code. On-demand documentation of simulation projects, including model variables and parameter sets, has been implemented to produce indexed PDF technical documents. Simulation projects currently being implemented in OMS3 by ARS, NRCS, United States Geological Survey (USGS) and university partners will result in large cost reductions in terms of model development, deployment, maintenance, and ongoing application.

26. Enhancement of CEAP Prototype Watershed Model. The CEAP Prototype Watershed model developed under OMS 2.2 was:.
1)enhanced with new Java components for erosion, nitrogen (N) cycling, and multi-flow direction routing;.
2)restructured to run under OMS3; and.
3)renamed as the AgES-W (AgroEcoSystem-Watershed) component-based model. AgES-W is currently being evaluated for N and sediment transport. Additional Java scientific components for water table depth and tile drainage were developed and are undergoing verification before incorporation into AgES-W. AgES-W has a fully-distributed simulation capability to better quantify conservation impacts on water quality at field to watershed scales, incorporating the most effective approaches for CEAP regionalized model customization.

27. Columbia, Missouri: Dissipation of Sulfamethazine and Tetracycline in the Root Zone of Grass and Tree Species. Veterinary antibiotics are introduced into the environment through land application of livestock manures. The effect of three grass and one tree species commonly used in vegetative buffers on the degradation of two antibiotics typically used in livestock production, sulfamethazine and tetracycline, was examined. Tetracycline dissipated rapidly under all vegetative treatments, indicating its relative instability in the soil environment. Sulfamethazine, however, was more persistent in soils and degraded most rapidly in the root zone of poplar saplings. The degradation rate was highly correlated to the microbial activity in the poplar root zone, indicating that this plant species supports a microbial community capable of rapidly breaking down sulfamethazine. Thus, use of poplar trees in vegetative buffers adjacent to fields receiving livestock manure applications could help alleviate the transport of antibiotics in the environment.

28. Herbicide Transport to Surface Runoff from a Claypan Soil: Scaling from Plots to Fields. A key challenge in evaluating the effect of various cropping systems on the transport of soil-applied herbicides has been the applicability of plot-scale results to the field scale. In this study, field-scale transport of atrazine and metolachlor were measured from two fields and the results compared to those predicted by an herbicide transport model developed at the plot-scale. The model developed from plot-scale data reasonably estimated herbicide concentrations at the field scale, particularly for atrazine. Inclusion of temperature and soil moisture into the plot-scale model significantly improved prediction of metolachlor concentrations at the field scale. The study also confirmed that atrazine and metolachlor losses were higher when the herbicide was not incorporated. The study showed that the model developed using plot-scale data was generally applicable to predicting herbicide concentrations at the field scale.

Last Modified: 7/1/2015
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