| This paper adopted the weed sample method to investigate the weed occurrence of soybean field in Liaoning and used field plot test method of preemergence soil-applied herbicides to study control effect and security in soybean field.Finally,80% Acetochlor·Clomazone EC was seleceted which can effectively prevent and remove weeds in soybean fields and it was safe for soybean.This study laid a foundation for the effective control of weeds in soybean field.The survey of the weed species results showed that there were a total of 19 families,34 species weeds in soybean field in Liaoning,including broadleaf weeds accounted for 73.53%,poaceae weeds accounted for 14.71% and other weeds account for 11.76 %.Annual weeds accounted for 55.88%,perennial weeds accounted for 29.41 % and other weeds account for 14.71%,among which the frequency of Barnyardgrass reached 100%.The abundance species of broadleaf weeds and the highest occurrence frequency of Barnyardgrass made it difficult to control in soybean field in Liaoning.The control effect,safety and yield about the four commonly preemergence soil-applied herbicides of 20% Imazethapyr AS,50% Acetochlorl EC,480 g/L Clomazone EC,80% Acetochlor·Clomazone EC in this study on weeds were determined,80% Acetochlor·Clomazone EC was the most effective in weed control,the yield of crops was the highest after application,and which was safe for crops and the surrounding environment.Analysis of test results showed that the test agent 80% Acetochlor·Clomazone EC was recommended to prevent annual weeds in spring soybean fields at the recommended dose of 1800-2400 g a.i./hm2.After 30 days of application,the control effect on the weed number and fresh weight for Barnyardgrass were respectively 80.5-90.9% and 81-90.8%;for Crabgrass were respectively 79.4%-90.2% and 80.2%-88.9%;for Goosegrass were respectively 80.8%-90.9% and 81.3%-89.6%;for Dayflower were respectively79.5%-88.8% and 79.6%-89.4%;for Purslane were respectively 80.5%-89.9% and 80.6%-90.0%;for Quinoa were respectively 81.5%-90.8% and 80.4%-89.4%.The control effect of 80% Acetochlor·Clomazone EC on the total weed number after 15 days was 80%-90.4% and after 30 days,the weed number and fresh weight fresh weight in soybean fields were 80.1%-90.2%and 80.5%-89.9%,respectively.The application period is before the emergence of soybean after sowing.The application method was soil spray treatment for 1 time,and the dosage per hectare is 450 kg. |
