Study on Controlling Weeds in Soybean Land by Covering Soil Surface with Sprays of 50% EC of Prometryne, 2,4-D and Acetochlor Between Sowing and Emergence

Good controlling effect to monocotyledon and dicotyledon weeds was achieved by soil spraying of 50%EC of Prometryne, 2,4-D and Acetochlor between sowing and emergence. The controlling effect was 76.58%～89.63% by weed quantity and 76.89%～90.22% by fresh weight in 45 days. The controlling effect is correlated with dosage. The optimum dosage is 420g per 667 m2, at which the controlling effect is the best and growth of soybean seedlings were not affected. All treatments increased the yield by 11.05%～22.68%.