Tuesday, November 6, 2007
211-7

The Validation of Risk of Soil Erosion Indicator for Use on Agricultural Landscapes in Canada.

Sheng Li1, David Lobb1, Brian McConkey2, Kevin H. D. Tiessen3, Bruce Walker4, and Michael Bock5. (1) University of Manitoba, Department of Soil Science, University of Manitoba, Winnipeg, MB R3T 2N2, Canada, (2) Agriculture and Agri-Food Canada, Agriculture Canada, Box 1030, Swift Current, SK S9H 3X2, CANADA, (3) Department of Natural Resource Sciences, McGill University, MacDonald Campus, 21 111 Lakeshore Road, Ste Anne de Bellevue, QC H9X 3V9, Canada, (4) BeauTerre Soilscapes Consulting Inc., Beaumont, AB T4X 1J4, Canada, (5) Alberta Agriculture and Food, Edmonton, AB T6H 5T6, Canada

A Risk of Soil Erosion Indicator (SoilERI) was developed in Canada through the National Agri-Environmental Health Analysis and Reporting Program (NAHARP) and was applied to Soil Landscapes of Canada (SLC) polygon scale. The SoilERI is an integration of tillage, water and wind erosion indicators (TillERI, WaterERI and WindERI). To validate the SoilERI, three representative SLC polygons were selected from each EcoZone and the TillERI, WaterERI and WindERI were validated against more sophisticated tillage, water and wind erosion models, i.e. the Tillage Erosion Model (TillEM), Revised Universal Soil Loss Equation 2 (RUSLE2) and the Wind Erosion Equation (WEQ), respectively. These more sophisticated erosion models were validated against Cs-137 data collected from 6 sites located in Manitoba, New Brunswick, Alberta and Ontario. Preliminary results show that the SoilERI estimates reflect the major patterns of total soil erosion in different EcoZones and the changes of total soil erosion over time. However, there are discrepancies, in some cases, large discrepancies between the SoilERI-estimated and the model-estimated soil erosion rates. When tested against the Cs-137 data, tillage and water erosion appeared to be the major forms of erosion in most Canada's agricultural land. The pattern of the model-estimated soil erosion generally agreed well with that of the Cs-137-estimated soil erosion. Systematic discrepancies did exist and were mainly due to the inaccuracy of the model input data. It was concluded that the SoilERI is sufficiently accurate for the assessment of soil erosion patterns on the SLC scale but the estimated soil erosion rate is only accurate relatively not absolutely.