Winter cover crops to reduce herbicide inputs in maize crops
Keywords:cover crop, maize, weed control, sustainable production
Winter cover crops potentially have a number of positive production and environmental benefits on subsequent maize (Zea mays) crops. A field study was undertaken in 2016/17 to evaluate the effects of winter cover crop residues on the emergence and growth of weeds, required herbicide inputs, and yields of maize in comparison to a winter fallow. Weed ground cover at maize canopy closure was 81—85% less than the winter fallow in plots with ryegrass (Lolium multiflorum), oats (Avena sativa) and gland clover (Trifolium glanduliferum) residues and 57% less in faba bean (Vicia faba). Ryegrass and oats residues maintained ground coverage of >70%, while clover had only 6% at canopy closure, but suppressed weeds similarly. In the absence of herbicides maize silage yields in plots with cover crop residues were similar to those in herbicide treatments, although maize establishment and growth was slower in oats and ryegrass.