|Fu, Guobin - WASHINGTON ST.UNIVERSITY|
|Chen, Shulin - WASHINGTON ST. UNIVERSITY|
Submitted to: Soil and Tillage Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 25, 2004
Publication Date: December 20, 2004
Citation: Fu, G., Chen, S., McCool, D.K. 2006. Modeling the Impacts of No-Till Practice on Soil Erosion and Sediment Yield with RUSLE, SEDD, and ArcView GIS. Soil and Tillage Research. 85(1-2):38-49. Available: http://dx.doi.org/10.1016/j.still.2004.11.009 Interpretive Summary: Reliable estimates of the effect on soil erosion and downstream sediment yield of crop management and land use changes are important in determining if these changes will result in the benefits expected. Changes in crop management practices may show reduced erosion on small plots, but the effect on sediment yield and fish habitat in downstream channels will be influenced by many factors in addition to those that cause small-plot erosion reduction. Applying the RUSLE and Arcview GIS to the Pataha Creek Watershed in southeastern Washington resulted in soil loss estimates on individual 10mx10m grid cells that showed average soil loss reduction from 11.1 to 3.1 t/ha.yr by converting from current to no-till practices on cropland. Using the Sediment Delivery Distributed (SEDD) model with the ArcView GIS indicated a sediment delivery from the watershed of 4.7 t/ha.yr under current management practices, and 1.5 t/ha.yr if all cropland were converted to no-till practices. This research is an important step in establishing procedures to determine the off-site benefits of using management practices such as no-till seeding or permanent contour grass strips. Determining off-site benefits of specific crop management practices is important because additional costs of applying these practices could be covered by external funds as part of fish habitat and species recovery efforts.
Technical Abstract: ArcView GIS and the Revised Universal Soil Loss Equation (RUSLE1) were used to estimate soil erosion and its response to no-till practice in Pataha Creek Watershed, a typical dryland agricultural watershed in southeastern Washington. With the aid of GIS and appropriate formulas specific to the Pacific Northwest region, L and S factors were calculated from DEM, and Req factors from precipitation map. K factors were obtained from SSURGO database, and C factors were calculated from RUSLE 105 using crop rotation and land use maps. ArcView GI was used to obtain soil erosion from each 10mX10m cell. The results show average cell soil loss of about 11.09 t/ha·yr under current land use. The Sediment Delivery Distributed (SEDD) Model integrated with GIS was employed to estimate the transport of eroded soil past the gaging station. The result showed that the average cell sediment yield from the 327 sq km area above the gaging station is 4.71 t/ha·yr, about 42.4% of the total soil loss. Channel erosion was not included in this study. The impacts of adopting no-till practices were then calculated by running RUSLE under the scenario of all the agricultural land under no-till practices. The average cell soil loss decreased from 11.09 to 3.10 t/ha·yr for the whole watershed and from 17.67 to 3.89 t/ha·yr for cropland under no-till. The average cell sediment yield to river channel decreased from 4.71 to 1.49 t/ha·yr for the entire watershed and from 7.11 to 1.55 t/ha·yr for cropland under no-till scenario. The contribution of cropland decreased from 92.4% to 72.8% for soil loss and from 87.4% to 60.1% for sediment yield if all the cropland in the Pataha Creek Watershed were under no-till practice. These modeled results are consistent with other studies either in this or other regions.