|Williams, J. - TAES|
|Larney, F. - AG. CANADA RESEARCH STATI|
|Bullock, M. - AGRIC. CANADA RESEARCH ST|
Submitted to: Canadian Journal of Soil Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 23, 1998
Publication Date: N/A
Interpretive Summary: Agricultural simulation models are often used to assess management and government policy impacts on soil erosion. The information gained from simulation models is useful but only to the extent that the results are accurate. Wind erosion models have been difficult to evaluate until recent because of the lack of reliable field data with which to compare the computer simulated results. We evaluated the wind erosion submodel of the Erosion Productivity Impact Calculator (EPIC) model by comparing simulation results with field measured wind erosion data from southern Alberta,Canada. With measured wind speeds, the EPIC model predicted erosion on each day of the 7 days that erosion was measured in the field. Erosion was also predicted on days when erosion was not measured, indicating that not all the factors affecting wind erosion were being modeled. The effect of field length and surface water content, two parameters which have large effects on wind erosion losses, appeared to be adequately modeled with the EPIC submodel. The results of this study are encouraging and indicate that EPIC does a reasonable job estimating wind erosion.
Technical Abstract: Wind erosion models have been used to assess policy impacts on soil erosion, but validation of models has been difficult until recently. We evaluated the Erosion-Productivity Impact Calculator (EPIC) wind erosion submodel by comparing simulation results to field measured wind erosion sediment losses. Using standard model inputs and actual wind velocities, wind erosion was simulated for a field near Lethbridge, Alberta (49° 37' N, 112° 38'W) where field measurements of wind erosion were made in April 1992 on a Dark Brown Chernozemic soil. The EPIC submodel predicted erosion losses for each day that erosion was measured. The magnitude of erosion losses for days that erosion was measured was usually approximated closely. EPIC did overestimate erosion for one event, and also simulated erosion on 3 d when no erosion was recorded. The effect of field length was simulated adequately. The effect of surface soil water content on wind erosion appeared to be captured in the model, but only limited data available to evaluate this aspect of the model. Other portions of the model such as surface roughness and vegetative factor could not be evaluated in this study. However, the EPIC wind erosion submodel appeared to adequately simulate wind erosion on this field in southern Alberta.