The researchers tested different herbicides to control weeds in soybean fields. They found that pre-emergence herbicides like clomazon, metolachlor, pendimethalin, and alachlor reduced weed populations effectively. Post-emergence herbicides were only effective against one type of weed. The best weed control was with metolachlor at 2.0 kg/ha. Hand weeding gave the highest seed yield, followed closely by metolachlor at 2.0 kg/ha. All herbicide treatments were better than letting the weeds grow freely.