Soil Erosion from Winter Wheat Cropland under Climate Change in Central Oklahoma

Effects of climate change on soil erosion from a winter wheat field were investigated to determine what conservation practices would be required under climate change to maintain future soil erosion at no more than today's rates. Global Circulation Models (GCM) climate projections for climate change scenario RCP8.5 in Central Oklahoma were used. Hydrologic processes, winter wheat growth, and soil erosion were simulated with the Water Erosion Prediction Project (WEPP) model, and daily precipitation and air temperature were generated with weather generator SYNTOR. Tillage alternatives included conventional tillage with and without terraces, conservation tillage with and without terraces, double cropping winter wheat and soy beans, no till, and conversion to perennial pasture. Findings suggested that in Central Oklahoma soil erosion from winter-wheat fields under conventional tillage would double by mid-century under climate change scenario RCP8.5 with an up to 30% increase in daily rainfall amount for the upper 5 percentile of storms. A switch to conservation tillage would offset, on average, most of the anticipated increase in soil erosion. However, the uncertainty range of GCM climate projections was large and the target reduction in soil erosion could not be achieved for several of the climate projections. To overcome the uncertainty range of simulated soil erosion, more effective conservation practices such as the combination of conservation tillage and terraces, no-till, and/or land use conversion to pasture must be considered. Based on these findings, it is inferred that wide implementation of today's conservation programs and policies would likely suffice to offset the anticipated increase in soil erosion from winter wheat fields under the high greenhouse gas emission scenario.