Examination of weed control in maize using new herbicide nicosulfuron in selected planting patterns at conditions of north of Khuzestan

This experiment was conducted in 2010 and 2011 to evaluate the effect of new herbicide nicosulfuron and planting patterns of planting in furrow and on beds on weeds which decrease grain yield of corn at Safi Abad agricultural research center of Dezful, I. R. Iran. The experimental design was a randomized complete block with strip plot arrangement of treatments with three replications. Planting method was as vertical factor at three levels consisting: planting of corn in furrows, on beds and in furrows and changing of furrows to beds at 7– 8 leaf stage of corn. Application of herbicide nicosulfuron was as horizontal factor at five levels consisting: postemergence application of nicosulfuron at 0.0, 0.40, 0.60 and 0.80 kg ai ha-1 at 4 – 6 leaf stage of corn and broadleaf weeds growth and weed free check. The most effective planting pattern in reducing density and dry weight of weeds was planting of corn in furrows and changing of furrows to beds. Compared to the weedy check, all nicosulfuron treatments reduced total weed density and dry weight significantly, but there was not significant difference among different doses of nicosulfuron. The most effective planting pattern in increasing corn grain yield was planting of corn in furrows and changing of furrows to beds with 4.006 t ha-1 of grain yield. Application of nicosulfuron at 0.80 kg ai ha-1 and weed free check with 3.965 and 2.691 t ha-1 had the highest and lowest level of corn grain yield, respectively. According to this experiment for weed control and grain yield increase of corn fields planting of corn in furrows and changing of furrows to beds at 7– 8 leaf stage of corn in conjuction with postemergence application of nicosulfuron at 0.60 kg ai ha-1 at 4 – 6 leaf stage of corn and broadleaf weeds growth are recommended.