Improving Water Quality in Agricultural Watersheds Underlain by Claypan and Restrictive Layer Soils
Cropping Systems and Water Quality Research
Project Number: 3622-12130-005-00
Start Date: Jan 26, 2012
End Date: Jan 25, 2017
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.
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.