Soil erosion from winter wheat cropland under climate change in central Oklahoma

Authors: Garbrecht, Jurgen; Zhang, Xunchang

Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/5/2015
Publication Date: 6/1/2015
Citation: Garbrecht, J.D., Zhang, X.J. 2015. Soil erosion from winter wheat cropland under climate change in central Oklahoma. Applied Engineering in Agriculture. 31(3):439-454.

Interpretive Summary: Agricultural producers and conservationist have expressed concerns that current soil and water conservation efforts, based largely on climate observations and agronomic practices of the past century, will not keep pace with anticipated climatic changes. Options to mitigate impacts of potential climate change on soil erosion and sediment yield were investigated for winter wheat crops in central Oklahoma. The goal was to determine which conservation practices would be required under climate change to maintain future sediment yield at no more than today’s rates. The future climate selected for this investigation was the climate corresponding to continued global warming through the end of this century. The time period for which sediment yield was evaluated for the 30 year period from 2041 to 2070. A computer program that simulates rainfall, runoff, soil erosion, and sediment yield was used to estimate the sediment yield under future climate conditions. Future sediment yield for seven conservation practices were examined. The conservation practices were: 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. It was found that a switch from conventional to conservation tillage would offset, on average, most of the anticipated increase in sediment yield under predicted climate change. On steep slopes and erosion prone soils, more effective conservation measures such as terraces or no till may be necessary. Based on these findings it was inferred that wide implementation of today’s conservation programs and policies would likely suffice to offset the anticipated increase in sediment yield from winter wheat fields under anticipated climate change.

Technical Abstract: Effects of climate change on sediment yield from a winter wheat field were investigated to determine what conservation practices would be required under climate change to maintain future sediment yield at no more than today’s rates. GCM climate projections for climate change scenario RCP8.5 in West-Central Oklahoma were used. Hydrologic processes, winter wheat growth, and sediment yield were simulated with the 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 sediment yield from winter-wheat fields under conventional tillage would double by mid-century under climate change scenario RCP8.5 and 15% storm intensification. A switch to conservation tillage would offset, on average, most of the anticipated increase in sediment yield. However, the uncertainty range of GCM climate projections was large and the target reduction in sediment yield could not be achieved for several of the climate projections. To overcome the uncertainty range of simulated sediment yield, 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 sediment yield from winter wheat fields under the high greenhouse gas emission scenario.