Organic producers are interested in no-till cropping systems. In this study, we found that perennial clover can be converted to corn without tillage. Conversion tactics involved fall mowing in the third year of red clover, followed by between-row mowing of weeds and volunteer red clover in corn grown during the fourth year. Corn yielded 85% of the weed-free control with mowing conversion. In contrast, weed interference in tillage-based conversion and between-row tillage reduced corn yield 53%. Weed emergence was sixfold greater in the tilled conversion. Weeds were present in the corn row with mowing, but recently developed implements could control these weeds and further support a no-till conversion method.

Organic producers are interested in developing a no-till system for crop production. In this study, we examined management tactics to convert perennial legumes to annual crops without tillage. Our hypothesis was that reducing carbohydrate production in the fall by mowing would favor winterkill. Mowing treatments were imposed in the fall of the third year of alfalfa or red clover, and corn planted in year 4. The conventional practice of tillage to convert legumes to cropland was also included as a treatment. Mowing in autumn reduced red clover biomass 93% compared with alfalfa when measured 3 weeks after corn planting (WAP). Red clover biomass was still 75% less than alfalfa 6 WAP. Fall mowing suppressed red clover sufficiently to enable corn seedlings to establish, but corn seedlings did not survive in mowed alfalfa due to alfalfa competition. Corn grain yield following red clover was similar in the mowed and tilled treatments when weeds were present. Late season clover and weed growth reduced corn yields 46% compared with weed-free corn. Weed emergence in corn was three times higher after tillage compared with the mowed treatment. Converting red clover to annual crops with fall mowing will support a no-till system for organic farming.