Weed control efficiency and safety evaluation of pyroxasulfone in kenaf field
[Aims]In order to clarify the feasibility of the application of pyroxasulfone in kenaf field,and evaluate the impact of this herbicide on the yield of kenaf.[Methods]Soil spray method was used in laboratory bioassay and field trial was carried out to determine the weed control effects of pyroxasulfone and the crops safety in kenaf(Hibiscus cannabinus L.)field.[Results]Under laboratory conditions,pyroxasulfone had high activity against bamyardgrass(Echinochloa crusgalli),with GR50 and GR90 of 20.51 and 83.52 g a.i./ha.The GR50 and GR90 against amaranth(Amaranthus retroflexus)were 27.05 and 243.37 g a.i./ha,respectively.All of them were higher than that of the S-metolachlor.Pyroxasulfone mainly inhibited the plant height and fresh weight of kenaf,bamyardgrass and amaranth,but promoted the elongation of roots,while S-metolachlor,inhibited plant height,root length and fresh weight of crops and weeds.The selectivity index of pyroxasulfone to barnyardgrass and amaranth were 3.168 and 1.087,which was higher than the value of S-metolachlor(1.312,0.205).This result indicated that it was relatively safe to apply pyroxasulfone in kenaf field.The results of the field trial showed that pyroxasulfone significantly promoted the height,stem diameter,fresh bark thickness and fresh tare yield of kenaf in Xinyang and Yancheng.The yield of kenaf in Xinyang was higher than that in Yancheng,and the weed control efficiency(both the inhibitory rate of weeds plant and weight were higher than 85％)in Xinyang kenaf field was better than that in Yancheng.[Conclusions]It is necessary to scientifically apply pyroxasulfone according to strictly controled dosage and the species of weeds occurring in different areas.
万方数据
维普
