Producers are interested in tactics for managing crop residues when growing maize after spring wheat. We compared five systems of managing spring wheat residues: conventional tillage, no-till, strip-till, cover crop (hairy vetch) with no-till, and cover crop with strip-till following spring wheat. Conventional tillage consisted of chisel ploughing and discing, whereas strip-till consisted of tilling a 15-cm band centred on maize rows, which were spaced 76 cm apart. Plots were split into weed-free and weed-infested subplots. Grain yield in weed-free conditions did not differ among treatments. However, weed-free yield was nearly 40% greater than weed-infested maize in conventional tillage. In contrast, weeds reduced yield only 15% with strip-till. Weed density and biomass was two-fold greater with conventional tillage compared with the no-till and strip-till treatments. Weed seedlings also emerged earlier with conventional tillage. Increased weed tolerance with strip-till may be related to fertilizer placement. Maize growth and tolerance to weeds in no-till systems may be improved if a starter fertilizer is placed in the seed furrow.
