Submitted to: Catena
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/5/2016
Publication Date: N/A
Citation: N/A

Interpretive Summary: In semi-arid regions such as the Southern High Plains of Texas, soil erosion may occur due to the forces of wind or water. During the last several decades, conservation agricultural practices including specialized tillage and crop residue management have been developed to mitigate soil loss due to wind and water. In spite of these developments, soil is eroded from agricultural fields, reducing soil productivity, fouling the environment in downwind and downstream locations, and threatening agricultural sustainability. We employed a technique of estimating decadal rates of net soil redistribution developed by USDA-ARS and 30 years of water-borne sediment yield data to partition the total soil loss on graded terraces under two conservation tillage types into wind and water induced components. We found that no-till management reduced soil loss by about a third compared to stubble mulch tillage and that wind erosion was responsible for about 75 percent of soil loss in both tillage types.

Technical Abstract: Soil loss due to wind and water erosion degrades the soil and results in environmental problems downstream and downwind of the source field. Wind and water erosion may both occur to varying extents particularly in semi-arid environments. Soil conservation strategies require information about the processes of soil redistribution to mitigate its impact. However, very few studies have partitioned soil erosion between contributions of wind and water. We quantified wind and water erosion on six graded terraces under a uniform crop rotation since 1949 and two tillage management practices begun in 1981. Detailed runoff and sediment yield data have been recorded on all the terraces since 1984. We used a stratified random sampling design to collect soil which were then bulked to form six composites for each terrace. From an adjacent undisturbed native prairie, soil cores were collected and composited similarly to provide a reference. The cores were measured for 137Cs activity which was converted to 137Cs inventory. We then employed an established computer model that equates loss of 137Cs inventory with soil loss and direct measurement of water-borne sediment loss to estimate 30 year mean wind erosion losses on the terraces by tillage type. We found that no-till management reduced total soil loss by one-third compared with stubble mulch tillage, reduced water-borne sediment loss by about the same amount, and that for both tillage systems, wind erosion was responsible for about 75 percent of the total soil loss.