1a. Objectives (from AD-416):
Streams in the Salt River Basin in northeastern Missouri have a well-documented history of herbicide and sediment contamination problems and are representative of the Central Claypan Areas (Major Land Resource Area (MLRA) 113), which encompass 3.3 million ha in northeastern Missouri and south-central Illinois. Research has shown this area to be the most vulnerable within the Corn Belt to transport of atrazine by surface runoff. The key hydrologic feature of soils within MLRA 113 is the presence of a subsurface claypan with smectitic mineralogy. Soils with smectitic mineralogy and the presence of argillic horizons or fragipans that also serve as restrictive layers will have similar hydrology to that of claypan soils. This potentially extends the applicability of this proposed research to an area of over 18 million ha throughout the Midwest, including the following MLRAs: 106 (Nebraska and Kansas Loess-Drift Hills), 109 (Iowa and Missouri Heavy Till Plain), 112 (Cherokee Prairies), and 114 (Southern Illinois and Indiana Thin Loess and Till Plain, Western Part). Objective 1: Conduct field- and watershed-scale studies to assess the contribution of surface runoff, interflow, and groundwater recharge to contaminant transport in claypan watersheds. 1: Measure interflow transport of atrazine and nitrate (NO3-) at the landscape scale. Objective 2: Develop and assess the effectiveness of management practices and bio- and phytoremediation technologies for reducing hydrologic transport of agricultural contaminants. 2a: Assess the efficacy of vegetative buffer strips for reducing the transport of dissolved-phase and sediment-bound organic contaminants (herbicides and veterinary antibiotics). 2b: Compare the impact of bioenergy cropping systems to conventional cropping systems on sediment, nutrient, and herbicide transport. 2c: Assess the soil and water quality impact of a field-scale precision agriculture system on sediment, nutrient, and herbicide transport. Objective 3: Improve watershed models for targeting conservation practices on the landscape and to better assess the aggregate impact of field- and watershed-scale management practices on surface water quality. 3a: Improve the capability of models to simulate sediment, nutrient, and herbicide transport from diversified cropping systems, including bioenergy crops. 3b: Develop methods to target BMPs to vulnerable areas. Objective 4: Improve watershed management and ecosystem services through long-term observation, characterization, delivery, and application of information from agricultural watersheds and landscapes. 4a: Conduct long-term water quality monitoring and characterization of agricultural watersheds and landscapes to assess trends and cause-effect relationships in contaminant transport. 4b: Multi-Location Project: Estimate the impacts of projected climate change on regional water availability and quality (including watershed sediment yield), across diverse physiographic regions of the U.S., and their associated implications for conservation needs and agricultural productivity.
1b. Approach (from AD-416):
The impact of alternative and prevailing crop management systems on soil and water quality will be studied at field, farm and watershed scales. This research will focus on assessing water quality from plot to watershed scales, coordinated with soil quality assessments at plot and field scales. It also focuses on the development of tools and techniques to quantify the impact of implementing conservation practices within a watershed in the most economically efficient manner to achieve sustainable and targeted reductions of nutrients, sediment, and herbicide loadings to the region’s streams, rivers, and impounded waters. The proposed research will also examine the environmental effects of bioenergy crops compared to conventional grain crop production and assess the potential benefits of targeting bioenergy production to vulnerable landscape areas. Lastly, the nation-wide ARS watershed network will utilize its decades-long weather and stream discharge data to estimate the impacts of projected climate change on regional water availability across diverse physiographic regions of the United States, and their associated implications for conservation needs and agricultural productivity.
3. Progress Report:
FY13 was a year characterized by the installation of monitoring equipment at several sites and restoration of experimental sites damaged by the 2012 drought. Stream monitoring in the Salt River monitoring network was reduced to 4 sites, all located in the Long Branch watershed. Samples from the 3 Little River Drainage District sites have also been analyzed. Plot surface water monitoring installation at the Centralia research site was completed and monitoring has been initiated in FY13. Modifications are continuing to ensure quality results and operating equipment during freezing conditions. Weather-induced challenges from 2011 and 2012 resulted in failure to establish willow as a biofuel cropping system. Discussions with stakeholders resulted in a decision to change to a miscanthus bioenergy crop, planted in 2013, and expected to mature in 2014. Likewise some switchgrass plots failed to establish in 2012 because of drought, and were replanted in 2013. Thus droughty conditions for two consecutive growing seasons have set back the ability to evaluate side-by-side the grain and bioenergy cropping systems two years. Monitoring of the quantity and quality of interflow was also initiated at the one site identified as suitable for this purpose, along with monitoring of precipitation, soil moisture and temperature in the catchment area, and general soil characterization. Equipment was purchased for 2 sites and the search for a second site is continuing. At the experimental site of vegetative buffers, biological and physical characterization has been completed. Sorption data are pending. After the drought, the plots were in need of maintenance and care to restore vegetative cover. Testing is underway to determine where to implement the equipment for concentrated flow monitoring. At the Centralia Research site, the 2013 cropping season completed 10 years of the Precision Agriculture System. Grid soil sampling for fertility was completed in the spring of FY13. Additional soil sampling for soil quality was also done. Analysis of water and soil quality will be conducted in FY14 to evaluate the impact of site-specific management using precision technologies on water and soil resources and decide on the future of this research site. Modeling work focused on the conversion to a new version of Agricultural Policy/Environmental eXtender (APEX), the understanding of new input parameters, and the development of auto calibration and uncertainty analysis software. This software was used on the Greenley research site, owned and managed by the University of Missouri. APEX models of the plots were parameterized with the new version of APEX and with new landscape positions that take the buffers into consideration. However, calibration of APEX for the plots with buffers needs to wait for sufficient flow and water quality data. A method to develop index maps has been formalized for Goodwater Creek and is being applied to Long Branch Watershed, with application to other tributaries of Mark Twain Lake planned for FY14 after which the fractions of watershed classified as vulnerable will be correlated to constituent loadings.
1. Vegetative buffers reduce transport of Sulfamethazine. Veterinary antibiotics (VAs) can be introduced into the soil environment when animal manures are land applied , creating the potential for the development of antibiotic-resistant genes in soil microorganisms. Two studies were conducted in collaboration with researchers at the University of Missourito assess the mobility of the VA, sulfamethazine (SMZ), in soils collected from cropland, grass buffers, and tree-grass buffers. Soils collected from grass buffer or tree-grass buffers tended to have greater organic matter and lower pH than cropped soils, resulting in increased SMZ sorption. Because of its greater binding to the buffers soils, SMZ leaching through soil columns was also less for the soil collected from the tree-grass buffer compared to that of the cropland soil. These results showed that vegetative buffers create soil conditions that can enhance the binding of SMZ and impede its transport in surface runoff. This research will benefit land management, growers, and the public by providing evidence to support the use of vegetative buffers for mitigating VA transport from treated cropland; thus, decreasing the threat of spreading antibiotic resistant genes that could lead to difficulty in treating human pathogens with existing antibiotics. Publications supporting this accomplishment: 282436 and 285132
2. Agricultural Policy / Environmental eXtender (APEX) model parameterization and calibration. The APEX model has been developed to assess a wide variety of agricultural water resource, water quality, and other environmental problems over a complex area: landscape, whole farm, and watersheds. The model includes many input parameters whose values must be determined and adjusted to obtain a good match between model results and observed data. Scientists and researchers who want to use APEX need guidance about the steps of this process. USDA ARS scientists collaborated with University of Missouri scientists and others to highlight important parameters and provide guidance about the input parameters and how they can be adjusted to obtain results that match measured data. Several case studies are presented: a 35-ha field in north central Missouri, the 5720-ha Clear Creek watershed in central Texas, and several catchments at the Greenley research site in north Missouri. Together they provide examples of APEX applications to simulate streamflow, crop yields, and sediment, nutrient and atrazine yields. These results are important to ensure that APEX, a model used to estimate the environmental and productivity impacts of agricultural management practices, is correctly used. Publications supporting this accomplishment: 274823 and 283001
3. Sediment organic carbon (C) distribution in small lakes and ponds. Small man-made impoundments including farm ponds, drinking water reservoirs, and recreational lakes ranging in size from 0.5 to 250 acres occupy over five million acres of the land surface in the United States. Organic carbon buried in the sediments of these impoundments is an important component of the global C cycle and its measurement is critical to understand how the buried C can help alleviate carbon dioxide levels in the atmosphere. Essentially no standard methods are available for sediment sampling and calculation of sediment C in small (<12 acres) lakes and ponds. ARS researchers, collaborating with University of Missouri researchers, developed an accurate method to calculate and quantify the organic C content in lake sediments. The sampling method also aids in determining the distribution of organic C within sediments and improves our understanding of small lake contributions to global C accumulation. Results of this study are important to accurately quantify that portion of the C cycle represented by sediments in numerous small lakes in a given region, thereby aiding in research planning and decision-making. Publication supporting this accomplishment: 280161
Senaviratne, A., Udawatta, R.P., Baffaut, C., Anderson, S.H. 2013. Agricultural Policy Environmental eXtender simulation of three adjacent row-crop watersheds in the claypan region. Journal of Environmental Quality. 42:726-736.