Control Effects of Five Pre-Sowing Herbicides on Weeds and Their Selectivity Evaluation in Taraxacum koksaghyz Fields
To screen out the pre-sowing herbicides suitable for Taraxacum koksaghyz fields,an experiment was conducted to investigate control effects of different treatments,relative seedling-emergence rate,and different growth indexes of T.koksaghyz seedlings via spraying s-metolachlor ( A1 ),acetochlor ( A2 ),trifluralin ( A3 ),pendimethalin (A4),and butralin(A5)before sowing 5 days(C1),10 days(C2),15 days(C3),and 20 days(C4)and at the pre-emergence stages of weeds.In the experimental design,different dose gradients were established.Specifically,these gradients were set at 0.4 times (B1),0.6 times (B2),0.8 times (B3),1.0 time (B4),and 1.2 times (B5) the recommended dose.And then weed control effect and selectivity of these five herbicides were comprehensively evaluated by DTOPSIS method based on entropy weight assignment.The results showed that the order of factors affecting the weed control effect and relative emergence rate in T.koksaghyz fields was herbicide type>spraying time>dosage.Trifluralin was a better encapsulated herbicide before sowing in T.koksaghyz fields.A3B3C5 and A3B2C4,namely trifluralin 480 g/L EC at 213.6 g/667 m2 before sowing 20 days and trifluralin 480 g/L EC at 160.2 g/667 m2 before sowing 15 days,showed an excellent control effect and rachieved high rankings in the comprehensive weed control evaluation in T.koksaghyz fields,with plant control effect of 72.14％ and 86.05％,and the relative emergence rates of 144.85％ and 95.15％,respectively.Therefore,it is recommended to use trifluralin 480 g/L EC as the preferred encapsulated herbicide for T.koksaghyz fields,but the specific application dosage and ways need further optimization.The results could provide a reference for weed control in fields,facilitating the industrialized cultivation of T.koksaghyz.
Taraxacum koksaghyzherbicideweed control effectselectivity evaluation
万方数据
维普
