The effects of plant density, number and stages of weed control in corn (Zea mays L.) Varieties on seed yield and weeds dry matter in Kerman

In order to evaluate the effects of plant density, number and stages of weed control, on weeds dry matter and seed yield of corn varieties, an experiment was conducted in 2011 on research farm, College of Agric. Univ. of Shahid Bahonar, Kerman, Iran. It was in randomized complete block (RCBD) in factorial design, with 3 replications. Weed control treatments were W1: weed control 4 times (2, 4, 6 and 8 weeks after planting), W2: weed control 3 times (2, 4 and 8 weeks after planting), W3: weed control 2 times (4 and 8 after weeks after planting) and W4: no weed control during corn growth season. Corn varieties were Single cross 704 and Maxima from FAO580, and were planted under 70,000 and 90,000 plants in hectare densities. Corn seed yield, plant leaves area, leaves dry matter, steam dry matter, total plant dry matter and weeds dry matter were calculated. The results showed that W4 treatment showed significant different in seed yield reduction compared to other weed control treatments. W1, W2 and W3 showed no significant difference between each others, so it can be concluded that W3 treatment could be used as an effective and economic weed control treatment in Kerman. Increasing weed-crop interaction time, caused low plant leaves, leaf and stem dry matter, and total plant dry matter of corn. Higher corn density produced lower total dry matter, leaf and stem dry matter and weeds dry matter. Seed yield increased with higher density. Maxima variety had higher seed yield and plant leaves area than Single cross 704. It seems that higher density caused a better ability and weed competition, and produced higher seed yield.