CROP SEQUENCE AND TILLAGE EFFECTS ON WINTER-WHEAT DEVELOPMENT AND YIELD

A 3-yr field experiment was conducted on a Burford loam soil to examine how tillage practices and crop sequences affected the winter wheat (Triticum aestivum L.) crop in Ontario. Three-year crop sequences of wheat-wheat-wheat, soybeans (Glycine max Merrill)-wheat-wheat, corn (Zea mays L.)-barley (Hordeum vulgare L.)-wheat, corn-soybean-wheat, and alfalfa (Medicago sativa L.)-alfalfa-wheat were planted with zero-till, minimum tillage, or conventional tillage systems. When wheat followed wheat, plant populations and head numbers were lower and head emergence delayed relative to wheat following another crop. Grain yields were 20% higher on average when crops other than wheat preceded wheat. Reduced tillage treatments resulted in delayed head emergence, but final grain yield components and yield did not differ significantly among tillage treatments. Results from this study support the relatively common production practice of rotating winter wheat with other crops. In addition, the use of conservation tillage systems appeared to be feasible for winter wheat production under the soil and climatic conditions prevailing in this study.