Effect of cover crops and date of planting them in a variety of tillage on to control weeds corn

Combinations of reduced tillage with cover crops may be reduced or controlled weed in main crops in different conditions. One of the beneficial aspects of cover crops and applying different tillage methods is reducing weeds ratio. In this way, an experiment was conducted in two separate field and two factorial designs with 2 factors. First factor is cover crop consist of control (without plant cover), Vicia villosa (Foddervetch), Trifolium resupinatum (Persian clover) and Secale cereal (Rye) and second factor is three cover crop planting date in minimum or low tillage with disk and Conventional tillage separately with Moldboard plow and corn was grown as main crop. Results showed that biomass and weed number reduced significantly in first weeding in minimum tillage for Vicia villosa and Trifolium resupinatum in contrast to secale and control treatment. Pigweed, Chenopodium, and Johnsongrass are the most dominant weeds on that studied field was reduced with dramatically with Vicia villosa, Trifolium resupinatum and Secale cereal in minimum tillage in contrast to control treatment, but in point of total weed dry weight, Vicia villosa and Trifolium resupinatum had decreased their biomass significantly in contrast to ray and control treatment. Results showed that however conventional tillage reduced significantly total dry weight and number of weeds in cover plants than control, but the lowest weight and number were observed in minimum tillage and rye cover treatment (but non-significant). In this type of tillage weeds total dry weight in rye treatments showed decreasing trend.