Location: Agroecosystems Management Research2013 Annual Report
1a. Objectives (from AD-416):
Problems to be addressed through this agreement include the following four areas: 1. Improving our understanding of the aggregate effects of conservation practices at the watershed scale; 2. Improving our ability to select and place conservation practices on the landscape for maximum effectiveness; 3. Improving conservation practices to better protect water resources; and 4. Maintaining the effectiveness of conservation practices under changing climate and land use.
1b. Approach (from AD-416):
Improving our understanding of the aggregate effects of conservation practices at the watershed scale: 1. Field studies to develop remote sensing tools to better evaluate cover crop performance (CB/ACP). 2. Develop models/decision support tools to assess the effectiveness of cover crops (CB/ACP) and other BMP’s (All) at the watershed scale. 3. Enhance the landscape version of SWAT to better represent field-to-basin scale processes (All). Improving our ability to select and place conservation practices on the landscape for maximum effectiveness: 1. Develop mapping techniques for placing specific practices within watersheds based on terrain and soils data. 2. Develop methods of terrain analysis for improved mapping of soil wetness in glacial terrain. 3. Validate the CEAP National Assessment conducted with SWAT at multiple scales. 4. Assess and compare the trade-offs of no-till adoption, and support the development of nutrient management recommendations for water quality protection, at the watershed scale. Improving conservation practices to better protect water resources: 1. Quantify nutrient management effects on water quality at field and watershed scales. 2. Watershed scale studies to systematically validate phosphorus site assessment tools in support of NRCS 590 (nutrient management) standard. 3. Watershed scale assessment of combined conservation practices. Maintaining the effectiveness of conservation practices under changing climate and land use: 1. Use reservoir sedimentation, land use change, and climate information to anticipate future reservoir sedimentation and needs for additional conservation under changing climate. 2. Enhance SWAT model routines for urban landscape BMPs. 3. Apply erosion (WEPP, etc.) and water quality (WEPP-WQ, etc.) models to catchments ranging from field- to farm-size and watershed scale, to assess the impacts of current and alternative land management systems and conservation practices under current and future climates.
3. Progress Report:
Watershed-scale data were collected at the Walnut Creek Watershed, in Story County, Walnut Creek, Jasper County, and the Southfork of the Iowa River, Hamilton and Hardin County, Iowa. Measurements of water flow, dissolved oxygen, temperature and pH were made, as well as nitrate and phosphorus (P) concentrations, E. coli and Enterococcus, and sediment. These data and meteorological data were placed in the STEWARDS (Sustaining the Earth’s Watersheds: Agricultural Research Data System) database. Geographic Information System (GIS)-based methods of processing Light Detection and Ranging (LIDAR) data for the purpose of hydrologic mapping were developed and applied to watersheds. Geographic Information System layers combining the hydrologic mapping and land surface data can be combined with other data layers containing cropping and management information to identify locations in watersheds where conservation practices would be most effective. Phosphorus transported in runoff from long-term field sites with swine manure or without swine manure in the South Fork of the Iowa River were compared. Phosphorus loading in runoff was similar. Further research was initiated to compare the runoff data soil P data from the same sites over the study period.