EFFECTS OF SOIL EROSION ON YIELD OF CORN

Abstract

Historically, special or intensive soil conservation methods have been recommended to control soil and water losses and maintain crop yields. However, farmers have not adopted these recommendations due to the high-energy input and the resulting reduction in high-value crop acreage. Crop yields do not appear to justify the cost of erosion control. Over a 10-yr period at Guelph, corn grown one year in a 4-yr rotation of corn, oats, hay and hay on runoff plots yielded 200–400 kg/ha above the average annual yield of corn grown continuously. Soil erosion losses averaged < 0.01 cm/yr from corn in rotation compared with 0.125 cm/yr from continuous corn. Under uniform cropping at the end of the period, corn grain yields did not reflect differences in soil erosion. In a subsequent 6-yr period, continuous corn with stover left on the soil surface and no tillage controlled soil erosion to < 0.01 cm/yr. The greatest soil and nutrient losses (0.36 cm soil, 87 kg N/ha and 59 kg P/ha/yr) occurred when stover was removed and the plots plowed in the fall. Corn grain yield was not reduced by these losses.