| Abstract: In order to screen chemical herbicides for leek seedling weeding, 33% pendimethalin EC (Emulsifi able Concentrates), 96% s-metolachlor EC 80% fl umetsulam water dispersible granules and 90% acetochlor EC were sprayed and six combinations of herbicides were set up. Under the conditions of no fi lm mulching and fi lm mulching, the herbicides were sprayed on the ground after leek sowed. The results showed that on the 30th day after treatment, the control effect of plant density was 89.07%～99.89% in fi lm mulching group, and that was 95.26%～99.14% in no fi lm mulching group. On the 45th day after treatment, the control effect of plant density was 88.90%～97.81% in fi lm mulching group, that was 94.53%～97.35% in no film mulching group. The plant density control effect and fresh weight control effect of the tested combinations were ideal with a long duration, which was safe for subsequent crops. In conclusion, 96% s-metolachlor EC blended by 80% fl umetsulam water dispersible granules in fi lm mulching group had better control effect. The plant density control effect and fresh weight control effect were 97.81% and 99.92% respectively, and the number of leek plants per unit area was the highest. The plant density control effect and fresh weight control effect of 33% pendimethalin EC blended by 80% fl umetsulam water dispersible in no fi lm mulching group were 97.35% and 99.94% , respectively. |