Water Resources Research Act Program

Details for Project ID 2015ID201B

Linking Agronomic Soil-P with Water Quality in Palouse Cropping Systems

Institute: Idaho
Year Established: 2015 Start Date: 2015-03-01 End Date: 2017-02-28
Total Federal Funds: $29,916 Total Non-Federal Funds: $62,003

Principal Investigators: Daniel Strawn, Erin Brooks

Project Summary: Excess phosphorus and nitrogen in watersheds are causing severe degradation of water quality, impairing surface water for recreation and drinking, and severely deteriorating ecosystem health. The largest contributor to water quality degradation is non-point phosphorus inputs, which is the target of many TMDLs. In this project, we will conduct experiments on soil P availability and watershed export from a long-term agriculture watershed research site. The catchment is located on the R. J. Cook Agronomy Farm (CAF) on the Palouse landscape in the Northwest Wheat and Range Region (NWRR), which covers up to 4 million hectares of non-irrigated cropland in northern Idaho, north central Oregon, and eastern Washington. Many of the surface waters in the region have impaired water quality from excess nutrients and sediments. The goal of this proposed research is to link soil and topographic attributes with potential P runoff loss. The following objectives are proposed to achieve the goal of the project: 1. Develop a spatial understanding of the net accumulation of phosphorus throughout a catchment on the Cook Agronomy Farm and associate it with soil properties and landscape position. 2. Measure surface and subsurface P transport within the catchment via artificial drains and surface runoff. 3. Measure dissolved and particulate P species in runoff from the catchment at different times of the year. The above objectives will be related to historic P fertilizer application rates, crop yield, and soil properties at sites within the catchment at the CAF research site. At this site, we have an ongoing study that is addressing the soil P adsorption and speciation. This proposed research will extend the current research to link soil P properties with off-site leaching. Results will provide modern P fertilizer guidelines, as well as information on which soils pose the greatest risks for P runoff. Information will be used to design better agricultural practices to limit dissolved and particulate P runoff into surface waters.