SUMMARY
To investigate the effect of different green manures from Gramineae and Brassicaceae families on yield, some agronomic traits of forage maize, overgrowth with weeds and soil organic matter, an experiment was conducted based on a randomized complete block design with three replications for three consecutive years (2017-2020) at the Agricultural and Natural Resources Research and Education Centre of Southern Khorasan. Experimental treatments included control (without application of green manure) and application of green manures from the cultivation of barley, triticale, canola, arugula with their optimum and twice optimum densities. The results showed that barley and triticale at twice optimum density with 865.7 and 802.9 g m-2, respectively, had a higher green manure dry mass at the time of returning to the soil. Just before maize cultivation, soil organic matter with an average of 0.73 % was higher in barley green manure at twice optimum density compared to other treatments. Based on the results, the highest maize forage yield with 45.7 and 44.9 t ha-1 were achieved after treatment with barley green manure in twice optimum and optimum density (22.8 and 20.7 percent more than control treatment) and after that triticale in both densities, and canola and arugula at twice optimum density had the highest yield.