ZEAMAYS دوره بحراني كنترل علفهاي هرز در ذرت سيلويي

Critical period of weed control in silage corn (Zea mays)

A study was conducted to determine the critical period in silage corn (Zea mays) during 1998 in tehran (in Aburihan Campus). Treatments included weed free and weed infested period up to 3 leaf; 6 leaf; 10 leaf; 14 leaf; tassseling plus 1 week and to the end of growth season (weed free and weedy check). Treatment were replicated, four times in a complete randomized block design. Results based on Gompertz and logistic equation showed a critical period of weed control for forage yield from 4-5 to 12 leaf stages (based on 5% of acceptable damage); and for grain yield (5% of acceptable damage); from 4 to 13 - 14 leaf stage of corn development. Correlation between dry matter of weed and corn was shown that between this two variables there was a negative relation. Number of weed in early season increased and then decreased.