Intercropping corn with soybean, lupin and forages: weed control by intercrops combined with interrow cultivation.

摘要

Two experiments were each carried out in 1993-94 at two sites in Quebec, Canada. In the first experiment, silage maize was intercropped with soyabeans, lupins [Lupinus], Lolium multiflorum, L. perenne or Trifolium pratense, or with one of the legumes + one of the grasses or a mixture of grasses. In the second experiment, 1 or 2 rows of soyabeans or lupins were sown simultaneously with maize or 3 weeks later. When sowing was delayed, weekly interrow cultivations were used to control weeds. The density and biomass of monocot weeds, either in or between the maize rows, were not affected by cultivation or intercropping. The density and biomass of dicot weeds in maize rows were reduced by some intercropping systems. For the various cropping systems tested, the dicot weed biomass and density between maize rows showed the greatest effect (in some cases a reduction of 73-100% compared with the weedy control). A more effective dicot weed control was observed with delayed sowing, which allowed extra interrow cultivations. Intercrops that included soyabeans were more successful at reducing weed populations than those containing lupins. Undersown forages did not reduce weed biomass or density.