ABSTRACT:
Effects of simulated soil erosion on wheat yields were studied on a Reinland loamy very fine sand, a Newdale clay loam, and a Pembina clay loam in Manitoba. Erosion was simulated by scalping 0,5,10, and 20 cm of the Ah horizon with a road grader. Each soil removal treatment was split into three levels of fertilizer application-control, soil test recommendation, and a high rate. The amount and kind of nutrient added in each fertilizer treatment was based on soil test. Wheat yields, averaged over all fertilizer treatments, decreased consistently with increasing amounts of topsoil removed. The data showed the detrimental effects of soil erosion on productivity and how technology can mask these effects. With no fertilizer, yields differed vastly between the plots with 0 and 20 cm of topsoil removed. However, for the higher-than-recommended fertilizer level, there were no significant differences in yield for the same two topsoil removal treatments. An attempt was made to estimate the cost of soil erosion by determining the cost of fertilizer required to restore production. In some cases as much as $90/ha for fertilizer was required to restore productivity. In other cases even a very high rate of fertilizer did not produce a yield equal to the control without fertilizer. In most instances nutrient content in the grain was not affected by topsoil removal treatment. Thus, the major nutritional effect of topsoil removal was a yield reduction.
Footnotes
R. Morrison Ives is a former graduate assistant and C. F. Shaykewich is a professor, Department of Soil Science, University of Manitoba, Winnipeg, R3T 2N2.
- Copyright 1987 by the Soil and Water Conservation Society
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