Effect of tillage system on yield and weed populations of soybean (Glycin Max L.)

Field experiment was conducted at Agricultural and Natural Resources Research Center of Golestan Province, Iran, to determine the effects of tillage system and weed management regime on yield and weed populations in soybean (Glycin max L.). The experimental design was a split plot where the whole plot portion was a randomized complete block with three replicates. Main plots were tillage system: 1- No-till row crop seeding, 2- No-till seed drilling, 3- Tillage with disc harrow and drill planting, 4- Tillage with chisel packer and drill planting. The subplots were weed management regimes: 1-Weed control with herbicide application, 2- Hand weeding, 3- Herbicide application plus hand weeding, and 4- Non-weeding. Results indicated that the main effects of tillage system and weed management regime were significant for seed yield, pod number per plant, seed number per pod, weed density and biomass, while their interaction were signifi cant only for weed density, weed biomass, and seed number per pod. The highest grain yields (3838 kg ha(-1)) were recorded for No-till row crop seeding. The highest seed yield (3877 kg ha(-1)) also was recorded for weed control with herbicide and hand weeding treatment, followed by hand weeding (3379 kg ha(-1)).