Tillage effects on corn production in a coarse-textured soil in southern Ontario

Minimum tillage has been shown to slow early corn (Zea mays L.) growth and reduce grain yields in some soil types and under some climatic conditions. To overcome these limitations, the no-till (NT) system can be modified by incorporating residues and loosening the soil in a zone over the center of the row while leaving the interrow area untilled. This study compares soil temperatures and corn growth and productivity under zone till (ZT), NT, and conventional tillage (CT) systems in a coarse-textured soil (Psammentic Hapludalf) located in southwestern Ontario, Canada. Soil temperature at the 4-cm depth decreased with decreasing tillage intensity from CT to NT during warmer years but was similar in CT and ZT during a cooler year. This resulted in reduced growing degree days in the seed zone with decreasing tillage. Lower soil temperatures in NT did not delay the initiation of corn seedling emergence but did reduce the rate of emergence compared with CT plots. Corn growth rates were found to be similar among tillage systems in the early part of the growing system but were higher for both the ZT and NT systems during late vegetative and early reproductive growth. Grain yields increased as tillage intensity decreased in a year with drier conditions at tasseling but were similar across tillage systems in the other 2 yr. These results suggest drat converting a NT system to a ZT system would neither result in significantly higher yields, nor cause a serious grain yield reduction relative to CT.