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 improv ement and double cropping represent promising systems for the preserva tion of soil, productivity and sustainability in Ontario agriculture. Field experiments were conducted in 1988 and 1989 to investigate the e ffect of planting date and tillage system on corn silage and grain yie ld for corn planted into either an established alfalfa sod or bare soi l. There were no differences in grain and total biomass yields between corn planted in May under the no-till treatment and corn planted in M ay under the fall-plowed treatment, in both years. In 1988, delaying c orn planting until after first-cut hay harvest on fall-plowed plots di d not result in grain yield reduction compared with May-planted corn u nder the same tillage regime. Grain yield was reduced significantly in 1989 by a delay in planting. Corn silage yield was equivalent among a ll systems in 1989, indicating that no-till systems can be used effect ively for producing alfalfa hay and silage corn. In 1988, rainfall in June was 7% of the average value, and as a result planting difficultie s resulted in low silage yields, particularly in the no-till treatment . However, under conditions of adequate soil moisture, no-till corn fo llowing alfalfa should produce yields comparable to those with convent ional tillage systems, while enhancing soil properties.