Theses and Dissertations Collection

Climate variability and anthropogenic climate change present challenges in achieving sustainable agriculture. One of the challenges in maintaining a healthy agroecological system is climate driven soil erosion. In the Inland Northwestern United States temperatures are expected to increase by as much 4°C and cool season precipitation is expected to increase 5-10% by the mid-21st century. The sensitivity of soil loss to projected changes in climate was simulated using the Water Erosion Prediction Project (WEPP) model. Ensembles of modeling experiments were performed by altering temperature, precipitation and precipitation extremes for a variety of hill slopes and both conventional and no-till cropping practices. Temperature was found to influence erosion through more indirect processes such as precipitation phase changes and changes in erodibility. In contrast, precipitation impacted soil loss more directly and it was found that while changes in mean precipitation increased erosion, large increases in erosion were also seen when extreme events were isolated. We additionally examined projected changes in soil loss by directly using downscaled climate projections from 20 global climate models. The GCMs found that future soil erosion amounts are projected to increase under all 20 models. These model results suggest increases in soil loss rates under future climate change that will present additional challenges to agricultural sustainability and prompt adaptation practices to conserve soil.