Abstract: This study carried out a random group test design in the field pharmacodynamic experiments,aiming to confirm the control effects of precision metolachlor·nicosulfuron·atrazine 40% OD against annual weeds and its safety in spring cornfield.The results showed that the control effects of precision metolachlor·nicosulfuron·atrazine 40% OD suspension （effective component） at 600,900,1 200,and 1 800 mL/hm² doses on weeds increased proportionally with the dose,and the control effect of each treatment on weeds at 30 d post-application was greater than that at 15 d post-application.At 30 d post-treatment,the fresh weight control effects of Echinochloa crusgalli,Chenopodium album,Amaranthus retroflesus ,and Solanum nigrum were 93.1%-100.0%,93.6%-100.0%,95.4%-100.0%,and 97.0%-100.0%,respectively. The total fresh weight control effect was 94.9%-100.0%.The total control effect of the three control medicaments was less than the three mixed medicaments.Precision metolachlor·nicosulfuron·atrazine 40% OD can be used at 900-1 200 mL/hm² doses in spring cornfield. It is safe on spring corn and controls weeds effectively with increasing production.Therefore it can be used as the major herbicide in spring cornfield.

Key words: Precision metolachlor·nicosulfuron·atrazine 40% OD, Spring corn, Weed control, Security