What effect do long-term cropping systems have on changes in soil erodible fraction and surface roughness?
This study suggests that long-term cropping systems may affect initial erodible fraction and subsequent overwinter changes and to a lesser extent surface roughness. The sites in this study had quite similar soil texture and organic carbon levels but variable cropping histories. The Fairfield site had almost all the surface residue removed for three years previous to the study initiation. This management technique resulted in a rapid increase in the erodible fraction and high erosion risk for a majority of the study. The Wilson site, which had the lowest initial erodible fraction of all sites, had been in a zero tillage system for seven years prior to the fallow season in 1993. Surface residue can protect the soil from climatic elements either directly or by trapping an insulative snow cover, but Figure 2. Parallel to tillage direction surface roughness (random) at two overwinter sites near Lethbridge, Alberta since surface residue amounts were similar to amounts at the other sites at s
