The effect of cover crop rye, hairy vetch and residuals on weeds, yield and yield components of wheat

In order to evaluation the effect of cover crops and their residues on weed management, wheat yield and yield components, an experiment was conducted in two stages. Evaluations were performed in randomized complete block design as split plot. At the first stage, cover crops grew for 45 days as second factor involved rye, hairy vetch, mixed of rye- hairy vetch and control without cover crop. In the next stage, wheat has planted after residuals management as first factor (include incorporated residuals, mowed residuals and herbicide application). The Results showed standing cover crops, before residuals management, rye and mixed treatments reduced density (as average 60%) and dry weight (87%) of grasses significantly rather than control treatment. After residue management, mowing and herbicide application had highest and least density of narrow weeds respectively. On both samplings, cover crops decreased intensively density and dry weight of grasses at the stages of booting (59 and 62% respectively) and maturity (60 and 68%) of wheat. The cover crop and residuals management interaction showed higher harvest index when rye-cover crop killed by herbicide and rye- hairy vetch mix treated by mowing. Since cover crops and also their residuals in soil declined severely density and biomass of narrow weeds especially as rye-hairy vetch mix (72 and 75 percent respectively), then cover crops appear to be profitable for weed management due to delay or decline weed germination and reduction of wheat-weed competition ensued from it even for short time