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United States Department of Agriculture

Agricultural Research Service

Research Project: Integrated Strategies for Improved Water Quality and Ecosystem Integrity within Agricultural Watersheds

Location: Water Quality and Ecology Research

2013 Annual Report

1a. Objectives (from AD-416):
Objective 1. Develop and evaluate farm and land management practices that reduce erosion, conserve soil, improve water quality, and protect ecological resources. Sub-objective 1a. Quantify the effects of conservation practices on runoff water quality and soil resources in Beasley Lake Conservation Effects Assessment Project (CEAP) watershed. Sub-objective 1b. Assess the influence of conservation practices on ecology and agricultural contaminant fate and transport in alluvial plain landscapes. Objective 2. Characterize and/or quantify the structure, function, and key processes of ecosystems in agricultural settings. Sub-objective 2a. Evaluate how nutrients, pesticides, and sediments interact with watershed hydrology to influence mechanisms regulating water quality and aquatic ecosystem structure and function in agricultural watersheds. Sub-objective 2b. Examine effects of water flow, climate-change-induced drought, and agricultural nutrient contaminants on stream microbial productivity and nutrient processing. Sub-objective 2c. Examine associations between fish species composition, hydrologic connectivity, and hypoxia in agricultural watersheds. Objective 3. Integrated assessment of the effects of agriculture on ecosystem services for watershed-scale endpoints. Sub-objective 3a. Develop integrataed remote sensing tools to better evaluate wetlands and riparian buffers. Sub-objective 3b. Develop agricultural conservation strategies to adapt to climate change. Sub-objective 3c. Develop integrated modeling tools to assess the effectiveness of conservation practices that enhance ecosystem services at multiple scales.

1b. Approach (from AD-416):
Long-term viability of U.S. agriculture depends upon implementation of management strategies that address goals of environmental sustainability and economic viability. Despite significant financial investment in conservation practices and water quality protection over recent decades, water quality issues remain unsolved in many agricultural landscapes. Off-site and downstream impacts of agricultural water pollution continue to raise concerns, most notably marine dead zones linked to excess nitrogen (N) and phosphorus (P). Biodiversity continues to decline due to water quality and habitat degradation. Future influences on environmental quality include synergistic effects of climate change, biofuel production, increased human population and exotic species. To address issues of water quality and watershed ecosystem function, investigations will pursue complementary approaches that consider the entire landscape, from upland fields to receiving water bodies. First, farm and land management technologies that reduce erosion, pesticide, and nutrient losses, conserve and improve soil, and protect ecological resources will be assessed. Second, studies will be conducted to improve understanding of structure, function, and key processes of aquatic systems, guiding better management of these systems and providing a scientific basis for regulatory agencies to establish water quality criteria. Third, investigations will develop and assess technology for improving water quality and ecosystem function in agriculturally impacted aquatic systems. Fourth, investigations will assemble and use long-term databases to develop and further enhance computer models for quantifying effects of conservation measures on agricultural watershed ecosystem services. This plan calls for experiments to be conducted across a range of spatial scales from the laboratory bench to the watershed.

3. Progress Report:
Effectiveness of farm and land management practices were assessed. Assembly of a comprehensive data set for Beasley Lake Watershed, a Conservation Effects Assessment Program (CEAP) watershed, is ongoing. Monitoring of lake water quality and fish populations, evaluation of runoff water quality from Conservation Reserve Program and buffer areas, and a two-cell sediment basin, continues. Watershed data includes soils, cropping patterns, cultural practices, topography, climate, water quality, ecology, and Light Detection and Ranging (LiDAR). These data are being input on the Sustaining the Earth's Watersheds: Agricultural Research Data System (STEWARDS) data base. Several small- to large-scale field experiments are being conducted to assess the effectiveness of a range of conservation practices. Effects of conservation tillage, nutrient, cover crop, and edge-of-field buffers on runoff water quality and changes in soil characteristics are assessed in a long-term row crop corn study. In another study, long-term (6 years) effects of transgenic corn and glyphosate application on soil characteristics are evaluated. Constructed wetlands, with and without rice, are being used to study the effectiveness of rice plants in trapping and processing nutrients and pesticides associated with a simulated storm runoff. A study is being implemented to evaluate the effectiveness of tailwater-recovery systems in improving runoff water quality through contaminant sequestering and processing. Characterizing ecosystem processes in agricultural watersheds was conducted. A comprehensive data set is being assembled for three low-flow agricultural stream watersheds. Monitoring of stream water quality, hydrology, land-use, microbial activity, fish populations, and aquatic invertebrate populations initiated in 2011 continues. Large-scale and small-scale experiments were conducted to assess ecological processes such as nutrient limitation and light limitation effects on algal growth and productivity. A large-scale experiment assessing organic matter processing rates is ongoing. Several small scale experiments are being conducted in artificial streams to assess microbial activity and ecosystem productivity with increased nutrient (carbon and nitrogen) and variable flow or drought conditions as well as examine the effects of suspended sediment from Mississippi Delta on fathead minnows. Watershed assessment of agricultural ecosystem services was conducted. Techniques are being developed to use LiDAR and remotely sensed riparian buffer vegetation data that will be integrated with AnnAGNPS to model changes in water quality. Climate data are being assembled to produce models of different climate conditions and possible effects of climate changes on water quality in Beasley Lake Watershed. Modeling simulations are being conducted with AnnAGNPS using data from large watershed-scale and smaller field-scale experiments assessing the effectiveness of conservation practices on water quality.

4. Accomplishments

Review Publications
Murdock, J.N., Shields Jr, F.D., Lizotte Jr, R.E. 2013. Periphyton responses to nutrient and atrazine mixtures introduced through agricultural runoff. Ecotoxicology. 22(2):215-230.

Locke, M.A., Zablotowicz, R.M., Steinriede Jr., R.W., Testa III, S., Reddy, K.N. 2013. Conservation management in cotton production: long-term soil biological, chemical, and physical changes. Soil Science Society of America Journal. 77:974-984.

Yuan, Y., Locke, M.A., Bingner, R.L., Rebich, R. 2013. Phosphorus losses from agricultural watersheds in the Mississippi Delta. Journal of Environmental Management. 115:14-20.

Lizotte Jr, R.E., Shields Jr, F.D., Knight, S.S., Cooper, C.M., Testa III, S., Bryant, C.T. 2012. Effects of artificial flooding on water quality of a floodplain backwater. River Research and Applications. 28(10):1644-1657.

Lizotte Jr, R.E., Knight, S.S., Locke, M.A., Steinriede Jr, R.W. 2011. Ten-year assessment of agricultural management and land-use practices on pesticide loads and risk to aquatic biota of an oxbow lake in the Mississippi Delta, USA, 349-371. In: B. Hendriks (ed.) Agricultural Research Updates. New York, NY: Nova Publishers, Vol. 2. 478 pp.

Tyler, H.L., Moore, M.T., Locke, M.A. 2012. Potential for phosphate mitigation from agricultural runoff by three aquatic macrophytes. Water, Air, and Soil Pollution. 223(7):4557-4564.

Knight, S.S., Cullum, R.F., Shields Jr, F.D., Smiley, P.C. 2012. Effects of channelization on fish biomass in river ecosystems. Journal of Environmental Science and Engineering. 1(8):980-985.

Tomer, M.D., Crumpton, W.G., Bingner, R.L., Kostel, J.A., James, D.E. 2013. Estimating nitrate load reductions from placing constructed wetlands in a HUC-12 watershed using LiDAR data. Ecological Engineering. 56:69-78.

Shields Jr, F.D., Lizotte Jr, R.E., Knight, S.S. 2013. Spatial and temporal water quality variability in aquatic habitats of a cultivated floodplain. River Research and Applications. 29(3):313-329. DOI:10.1002/rra.1596.

Jenkins, M., Liotta, J., Bowman, D. 2013. Inactivation kinetics of Cryptosporidium parvum oocysts in swine waste lagoon and spray field. Journal of Parasitology. 99(2):337-342.

Lizotte Jr, R.E., Shields Jr, F.D., Testa III, S. 2012. Effects of a simulated agricultural runoff event on sediment toxicity in a managed backwater wetland. Water, Air, and Soil Pollution. 223:5375-5389.

Shields, F.D., Knight, S.S. 2013. Floodplain restoration with flood control: fish habitat value of levee borrow pits. Ecological Engineering. 53:217-227 doi:10.1016/jecoleng.2012.12.046.

Tyler, H.L., Khalid, S., Jackson, C.R., Moore, M.T. 2013. Determining potential for microbial atrazine degradation in agricultural drainage ditches. Journal of Environmental Quality. 42:828-834.

Last Modified: 10/18/2017
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