CROP MANAGEMENT-SYSTEMS FOR CORN (ZEA-MAYS L) FOLLOWING ESTABLISHED ALFALFA (MEDICAGO-SATIVA L)

Crop manage ment systems utilizing no-till and legumes for soil improvement and double cropping represent promising systems for the preservation of soil, productivity and sustainability in Ontario agriculture. Field experiments were conducted in 1988 and 1989 to investigate the effect of planting date and tillage system on corn silage and grain yield for corn planted into either an established alfalfa sod or bare soil. There were no differences in grain and total biomass yields between corn planted in May under the no-till treatment and corn planted in May under the fall-plowed treatment, in both years. In 1988, delaying corn planting until after first-cut hay harvest on fall-plowed plots did not result in grain yield reduction compared with May-planted corn under the same tillage regime. Grain yield was reduced significantly in 1989 by a delay in planting. Corn silage yield was equivalent among all systems in 1989, indicating that no-till systems can be used effectively for producing alfalfa hay and silage corn. In 1988, rainfall in June was 7% of the average value, and as a result planting difficulties resulted in low silage yields, particularly in the no-till treatment. However, under conditions of adequate soil moisture, no-till corn following alfalfa should produce yields comparable to those with conventional tillage systems, while enhancing soil properties.