Wednesday, November 7, 2007
308-7

Using Landscape Restoration to Increase Crop Yield on Severely Eroded Hilltops.

Diane Smith1, David Lobb1, Thomas E. Schumacher2, and Sharon Papiernik3. (1) Soil Science, University of Manitoba, 13 Freedman Cres., Winnipeg, MB R3T 2N2, Canada, (2) Plant Science Department, South Dakota State University, NPB 247A, Brookings, SD 57007, (3) USDA-ARS-NPA-SPNRU, USDA-ARS, 803 Iowa Avenue, Morris, MN 56267

Tillage is a dominant soil erosion process in cultivated hilly landscapes and is responsible for local soil redistribution with the landscape. Topsoil is lost from upper slope positions and accumulates in lower slope positions and depressions. Ultimately, the loss of topsoil on eroded upper slope positions results in reduced crop yield which is not offset by yield increases in areas of accumulation. Landscape restoration is an alternative and logical management practice that can be used to restore the productivity of eroded hilltops by removing accumulated topsoil from depressions and replacing it on the hilltops where it had originated. Four field-scale sites were established in southwestern Manitoba to evaluate the net benefit of landscape restoration on crop productivity. A paired comparison design was used to compare yield differences on severely eroded upper slope positions and upper slope positions which have been restored with 10 cm of added topsoil as well as, a comparison between depressional areas and areas where 10 cm of accumulated topsoil was removed. Significant yield increases where observed on restored hilltops, ranging from 380 to 1077 kg haˉ¹, without any yield loss where 10 cm of topsoil was removed. These results have demonstrated landscape restoration can provide producers with a practical and agronomically effective management practice to restoring crop productivity in eroded landscapes.