Submitted to: Catena
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/18/2006
Publication Date: 8/1/2007
Citation: Li, S., Lobb, D.A., Lindstrom, M.J., Farenhorst, A. 2007. Tillage and water erosion on different landscapes in the northern North American Great Plains evaluated using 137Cs technique and soil erosion models. Catena. 70:493-505. Interpretive Summary: Total soil erosion is the integrated result of all forms of soil erosion – wind, water, and tillage. The relative contribution of each erosion process varies between landscapes and between landscape positions in a single landscape. The pattern of total soil erosion is complicated due to the linkages and interactions between the erosion processes. In this study, we investigated the patterns of water and tillage erosion and their relative contributions toward total soil erosion in two hilly landscapes. Combining water and tillage erosion models generally provided better estimations of total soil erosion than the component models on their own. More than 75 percent of the agricultural land in the North American Great Plains region is classified as hilly. Both water and tillage erosion contribute to the total soil erosion in this region, so it is important that both erosion processes, their linkages and interactions be accounted for in the assessment of total soil erosion. The information developed in this research will enable scientists, extension personnel, and land managers to use data currently available in national databases around the world for the assessment of soil properties, water, tillage and total erosion in hilly landscapes. In addition, an examination of the interactions between tillage and water erosion in topographically complex landscapes will aid in better understanding other landscape-driven soil processes such as water contamination, pesticide fate and greenhouse gas emission.
Technical Abstract: Total soil erosion is the integrated result of all forms of soil erosion – wind, water, and tillage. The relative contribution of each erosion process varies within different landscapes and within different landform elements. In this study, we investigated the patterns of water and tillage erosion and their relative contributions toward total soil erosion in two field sites characterized by undulating slopes and hummocky knolls. We also evaluated the potential of using landscape segmentation to assess water, tillage and total soil erosion in topographically complex landscapes. Water and tillage erosion were estimated using the established WEPP, WaTEM and TillEM models; total soil erosion was estimated using the 137Cs technique; and the landscapes were segmented using the LandMapR program. Combining water and tillage erosion models generally provided better estimations of total soil erosion than the component models on their own. On undulating slopes, tillage and water erosion both contributed considerably to total soil erosion; tillage erosion was dominant on upper slope positions and water erosion dominated on mid-slopes. On hummocky knolls, tillage erosion dominated the pattern of total soil erosion in both upper and mid-slope positions. The major patterns and variations in water, tillage and total soil erosion within given landform elements was predictable, indicating that landscape segmentation may be useful in assessing soil erosion and soil properties in topographically complex landscapes.