Effect of cover crops on weed control and corn grain yield in conservative tillage system

The use of cover crops before planting the main plant along with selecting the type of tillage can be considered as one of the effective methods in sustainable agriculture. In order to show the efficacy of this system, an experiment was conducted in a no-tillage system and with six treatments, barely (Hordeum vulgare L.), rye (Secale cereal L.), rape (Brassica napus L.), vetch (Vicia villosa L.), crimson clover (Trifolium incarnatum L.) and control, in a randomized complete block design with three replications, at the farms of agriculture and education research center and natural resources of Ardabil Province (Moghan) during the 2015-2017. Variance analysis showed that the effect of the treatments on the total weed density was significant. On average, in four sampling stages, total control of winter and spring weed at barley, rye, rape, vetch and clover treatments were 83.5,77.25,66,25,51, and 26.25 respectively. The results also showed that the soil cover percentage was significantly