Chemical and Mechanical Control of Soybean (Glycin max L.) Weeds

To evaluate effects of the various concentrations of two herbicides of the trifluralin and Imazethapyr and weeding on weeds control, yield and yield components of soybean (Glycin max L.), an experiment was carried out based on randomized complete block design with three replications at the Agriculture Land of Ghravolhaji Village in Kallale district of Golestan province in 2014. Treatments consisted of planting soybean under weeding, without weeding and application of trifluralin and Imazethapyr as 100% trifluralin, 75% trifluralin + 25% Imazethapyr, 50% trifluralin + 50% Imazethapyr, 25% trifluralin + 75% Imazethapyr, 100% pursuit, 100% Imazethapyr + 25% trifluralin, 25% Imazethapyr + 100% trifluralin, 100% Imazethapyr + 50% trifluralin and 50% Imazethapyr + 100% trifluralin. density of each weed, their total density and inhibition percentage were measured. Results showed that the effect of chemical weed control on all traits measured, except seed number per pot, 1000 seed weight, content of chlorophyll a and total chlorophyll, were significant. The highest leaf area, plant height, number of pods per plant, aerial plant dry weight, seed number per plant and seed weight per plant were observed in the treatment of the 100% Imazethapyr (238.67 cm2), weeding (57.69 cm), both treatments of weeding (33.10) and 25% Imazethapyr +100% trifluralin (28.3), both treatment of weeding (163.92 g) and 100% Imazethapyr (163.70 g), weeding (67.10 seed per plant), both treatment of weeding and 100% Imazethapyr + 50% trifluralin (10.27 seed per plant) respectively. The highest seed yield was obtained from weeding treatment (2383 kg/h). Based on the results, the highest content of protein and chlorophyll b in soybean were obtained from weeding treatment. The highest inhibition percentage of weeds was found in the additional treatment of 50% Imazethapyr + 100% trifluralin (75.19) and 100% Imazethapyr + 25% trifluralin (72.86). The lowest and highest total phenols content and proteins also were obtained in the treatment of 100% trifluralin. Although treatments mentioned above had inhibitory effects on weeds they also decreased the yield components and seed yield of the soybean.