Effect of Cover Crops and Nitrogen Fertilizer on Total Production of Forage Corn and Dry Weight of Weeds

To evaluate the effect of cover crops, split application of nitrogen and control weeds on forage corn and weed biomass a factorial experiment based on randomized complete block design with three replications and three factors was conducted at the Agricultural Research Station of Ardabil (Iran) during 2012 crop year. The first factor was cover crops (consisting of winter rye, hairy vetch, berseem clover, with and without weeding) as controls. The second factor was two levels of split application of 225 kg.ha-1 urea at two growth stages forage corn: the first level (N1= 1/2 at planting and 1/2 at 8-10 leaf stage), second level (N2= 1/3 at planting, 1/3 at 8-10 leaf and 1/3 one week before tasselling stage). The third factor consisted of two levels of weed control: weeding at 8 leaves and weeding one week before tasselling. Results showed that winter rye, hairy vetch and berseem clover cover crops decreased total weed dry weights up to 87, 82 and 65 % respectively as compared to control (without weeding). Cover crops and nitrogen application time had a significant effect on yield of fresh forage corn and cover crops. Based on the advantages of effective weed control and higher forage production of hairy vetch it can be recommended as proper cover crop.