Red Clover and Tillage Influence on Soil Temperature, Water Content, and Corn Emergence

No-tillage systems on fine-textured soil are not well suited for corn (Zea mays L.) because of problems with excess water, lower temperatures, and residue management during the early stages of corn growth. This is a problem, as corn is commonly used in rotation with wheat (Triticum aestivum L.) and soybean [Glycine max (L.) Merr.]. Furthermore, when corn follows winter wheat there may be additional problems associated with residue management during the early stages of corn growth. Hence, the objectives of this study were to measure the effect of the red clover (Trifolium pratense L.) cover crop underseeded in wheat and no-tillage on soil temperature, water content, corn emergence, surface residue, and yields in a wheat-cornsoybean rotation in southwestern Ontario. Treatments included conventional vs. no-tillage both with and without underseeded red clover in a wheat-corn-soybean rotation in a clay loam soil. A no-tillage and red clover treatment that had the wheat straw baled was also included. No-tillage (with and without red clover) increased soil water content by 2 to 5% and reduced soil temperatures by 1 to 2°C during early corn emergence. Soil drying occurred along the planting slot of the no-tillage treatments, which enabled the soil seed furrow to open and the corn seedlings to become water stressed even though the notillage treatments were wetter in the spring. Corn emergence in the no-tillage treatment without red clover was delayed by 3 to 4 d and the final plant stand was reduced by 24% compared with the conventional tillage treatment. The no-tillage treatment without red clover had 13% lower corn grain yield than the conventional tillage treatment averaged over three years. However, when red clover was included with no-tillage, corn emergence was increased and corn grain yields were not significantly different from conventional tillage in both 1994 and 1996. There was also 15% less dry weight of surface plant residue present in the no-tillage treatments when red clover was included. Hence, red clover alleviated some of the problems of no-tillage for corn production.