In corn/soybean/wheat rotations in Ontario, Canada, tillage is often conducted intermittently to remediate compaction, address residues, incorporate nutrients or to level the surface. To determine the impact of intermittent tillage on no-till soil structure and crop yield, a 10-year study was initiated in 1995 at the Woodstock Research Station, University of Guelph. Specific objectives were (1) to compare the yield potential of corn, soyabean and wheat under short term and long-term no-till, and (2) to determine the best time to conduct intermittent tillage in a corn/soybean/wheat rotation. Tillage increased corn, soyabean and wheat yields in comparison to both short-term and long-term no-till. No-till soyabean yields did not improve with increasing years under no-till. Corn yields were reduced under first year no-till, but by the second year of no-till, corn yields were equal to long term no-till yields. In a corn/soybean/wheat rotation occasional tillage should be conducted in advance of corn.
