Effect of cover crop in control of weed density and some qualitative and quantitative characteristics of sunflower

ABSTRACT: In order to study the effects of rye cover crops and winter wheat and spring barley on the density and type if weeds on field condition, a factorial experiment in a randomized complete blocks design, in which the first factor, the type of cover crops in three levels (rye, barley and wheat), the second factor, the mulch management of cover crops at two levels (living mulch, cutting of cover crops), third factor planting time of cover crops at two levels (Simultaneous with the cultivation of sunflower, 45 days after planting sunflowers) with two control treatment:1) without cover crop and without control weeds 2) without cover crop and with control weeds, with three replication was done in 2012, the Natural Resoures Research Institute, medicinal herbs of Samian in Ardabil. In this study is obtained highest weed density related to control to control (without cover crops and without control weeds), lowest weeds density related to control (no cover crop with a complete control weeds), rye, wheat, barley, respectively. The management style has no significant effect on the studied parameters. 45 days after the date of planting sunflower cove crops, weeds density has decreased approximately two- fold. Concurrent cultivation of cover crop with sunflower has caused the increase of factures related to sunflower.