Location: National Soil Erosion Research2012 Annual Report
1a. Objectives (from AD-416):
Objective 1. Advance the knowledge and improve mathematical representation of physical and biogeochemical processes affecting sediment, nutrient, and pesticide losses in runoff. Subobjective 1.1. Quantify surface and subsurface hydrologic effects on runoff chemical transport and ephemeral gully erosion. Subobjective 1.2. To identify practices that will optimize the benefits of no-tillage, while minimizing the risk of P losses via runoff, without sacrificing crop productivity. Subobjective 1.3. Identify practices to optimize drainage while maximizing nutrient removal efficiency. Objective 2. Protect off-site water quality by developing methods to reduce pollutant losses from agricultural fields and watersheds. Subobjective 2.1. Develop a BMP (Best Management Practice) to reduce nutrient and pesticide delivery from landscapes to drainage systems and water bodies and reduce greenhouse gas emissions. Subobjective 2.2. Test the impact of established and new conservation practices at the field and watershed scale. Subobjective 2.3. Determination of optimal BMPs for control of runoff, sediment, and chemical losses from agricultural fields and watersheds, under existing and future climates. Objective 3. Improve soil erosion and water quality models for better assessment and management of cropland, forestland, and other managed lands. Subobjective 3.1. Improve our ability to predict soil erosion and water quality. Subobjective 3.2. Develop techniques that enhance field-to-watershed model parameterization for improved hydrologic model predictions. Subobjective 3.3. Develop methods to optimize chemical monitoring parameters to minimize costs and uncertainties associated with characterizing selected endocrine disrupting chemicals in artificially drained landscapes.
1b. Approach (from AD-416):
Laboratory studies will be used to gain process-level understanding on the effects of topographic driven surface water convergence and soil hydraulic gradient driven subsurface flow on sediment and chemical loadings. Landscape attributes affecting convergence of surface and subsurface flows will be used to validate the lab findings on conditions for channel initiation and chemical transport. To identify practices that optimize the benefits of no-till while minimizing risk of P losses, laboratory experiments will be used to test a large array of fertilizers and production practices. Plot scale experiments will be used to evaluate practices over a 5 to 10 yr period as they relate to soil and water quality. To identify practices that optimize drainage while maximizing nutrient removal, lab and streamside fluvaria will be utilized. Treatments of various materials including gravel and woodchips below stream sediment will be tested, as will use of various heights of sediment dams, to reduce nutrient losses in stream water. Controlled drainage on tile drained fields to optimize soil moisture status to reduce excess loss of nutrients, in combination with a soil amendment of flue gas desulfurization (FGD) gypsum will be evaluated. This project will continue to monitor runoff and water quality in subwatersheds of the St. Joseph River (SJR) in northeastern Indiana, and also conduct ecological studies through an SCA with Indiana-Purdue University Ft. Wayne and a cooperative project with ARS-Columbus. Detailed flow and pollutant data in the SJR subwatersheds are available from 2003-present, allowing for both uncalibrated, calibration, and validation studies with a number of watershed hydrology, sediment, and water quality models. The models can also be applied in a forecasting mode, to examine impacts of widespread or targeted placement and implementation of various land management practices (e.g. conservation tillage, different crop rotations, buffer strips, etc.) on predicted runoff and pollutant losses. Use of information from Global Environment Models will be downscaled to develop modified climate inputs to the Water Erosion Prediction Project (WEPP) model. In-house and cooperative erosion model development, testing, and validation efforts will be conducted. Work will include maintenance of WEPP, including model scientific code, user interfaces, model databases, and user support. Cooperative efforts on development of a combined wind and water erosion model will be continued. A new WEPP-Water Quality model will be developed which will also allow examination of the impacts of projected future climate change on runoff, sediment, and chemical losses and how management practices to reduce these losses may change. Geostatistical scaling techniques will be applied and evaluated to allow linkage of various soil parameters (i.e., hydraulic conductivity, porosity) across scales ranging from a few hectares to subbasins of 10,000+ ha. Loading of endocrine disruptors and selected metabolites to the SJR will be examined for significant relationships between analytes. Through statistical correlation analysis, potential surrogate analytes will be identified.
3. Progress Report:
Substantial progress has been made on laboratory and field studies on this new project. A lab study on the effects of surface topography under a drainage condition was completed. A new laboratory recirculating flume using plastic tubing was constructed and has been undergoing testing for chemical movement (bromide tracer) from a saturated sand bed into overflowing water. In the National Soil Erosion Research Laboratory fluvarium, sediments with high hydraulic conductivity were tested to examine their impacts on chemical desorption and adsorption. Data collection was accomplished in Indiana and Kansas at field sites being used to study gully characteristics and development. Plots were established at the Throckmorton Purdue Agricultural Center to study how minimize soluble phosphorus losses from no-till farming. Soils from these plots have also been collected for use in a companion laboratory study. Field plots were established at the Purdue Davis Agricultural Center to study the effects of controlled drainage and gypsum soil amendment on crop production and water quality. Water flow and samples for nutrient and herbicide analyses were collected from field, ditch, and stream sites in the Upper Cedar Creek Watershed (UCCW) in northeastern Indiana. Weather in 2012 has been extremely hot and dry, thus number of water samples for analysis have been much less than in previous years. Three additional soil moisture and meteorological stations have been installed within the UCCW. Measured field to watershed scale soil moisture data has been obtained and processed for the 2011 European Space Agency SMOS remotely sensed soil moisture project that covers the UCCW. Validation of SMOS algorithms is in progress. Significant progress toward calibration/validation of Agricultural Policy Environmental EXtender (APEX) and application of the model to assess the impacts of conservation practices at the field scale has been made. Natural Resources Conservation Service (NRCS) is currently implementing and using a version of Wind erosion Prediction System (WEPS) containing the WEPP hydrology/erosion code. Cooperative projects are underway with the Forest Service, Washington State University, Iowa State University, and the University of Iowa on new WEPP interfaces. The St. Joseph River Watershed Conservation Effects Assessment Program Watershed Assessment Study (CEAP WAS) has been selected as one of two benchmark watersheds to be used for a multi-Agency effort to assess the impacts of conservation practices on environmental quality at the watershed scale. This will be an intensive 1-yr effort, compiling monitored water quality and quantity data, ecological assessment data, cropping system attribute data, as well as field and watershed scale modeling efforts to provide the other agencies with information on the effectiveness of current conservation practices, and how those agencies may better target conservation practices in the future.
Erpul, G., Gabriels, D., Norton, L.D., Flanagan, D.C., Huang, C., Visser, S. 2012. Mechanics of interrill erosion with wind-driven rain. Earth Surface Processes and Landforms. DOI: 10.1002/esp.3280.