| As a highly active and lowly toxic herbicide applied in soybean, Imazethapyr used in preplant and preemergence soil treatment and postemergence foliar treatment can control gramineous and broad-leaved weed efficiently. It was developed by BASF(American Cyanamid). In this paper, the weed control spectrum, control efficacy, safety to different crops, Influence on aftercrop, detoxifcation of protectants, herbicide mixtures of Imazethapyr were studied in order to improve its application technique in soybean and alleviated injury of its residue to aftercrop.Weed control spectrum of Imazethapyr was studied by potted experiment. It controlled efficiently some annual gramineous and broad-leaved weed, such as Echinochloa crusgalli (L.) Beauv., Setaria faberii Herrm., Setaria glauca (L.) Beauv., Digitaria sanguinalis (L.) Scop., Polygonum bungeanum Turcz., Polygonum lapathi folium L., Xanthium sibiricum Patrin., Elsholtzia ciliata (Thunb.) Hyland, Abutilon theophrasti Medic. Solanum nigrum L. , Chenopodium album L. , Chenopodium serotinum L. , Capsella bursa-pastoris (L.) Medic., Commelina communis L.. It also inhibited growth of some perennial weeds, such as Cephalanoplos segetum (Bunge) Kitara., Sonchus brachyotus DC., and so on. Weed control spectrum of Imazethapyr was broader than other herbicides' in soybean field such as Acetochlor, chlorimuron ethyl, Clomazone, Sethoxydim and Fomesafen. Acted as soil treatment, the higher the moisture of soil, the better the control efficacy of Imazethapyr was. Contrariwise, the soil moisture was lower, the control efficacy was worse too. Applied in postemergence herbicide, the best temperature of applying Imazethapyr is 5-15. The higher the temperature, the lower the control efficacy of of Imazethapyr was when the temperature was over 15.Through a field experiment, we made certain the best dose range of imazethapyr in soybean is 75-105g a.i. /hm2. In this range, imazethapyr is safe to tested American soybean cultivars, but the injury to tested Japanese soybean cultivars was heavy. There was no effect to the growth of tested Chinese American soybean cultivars and was no reduction in yield, including Dongnong42, Hefeng39, Heinong40, Suinong14. The resistance of Dongnong42 And Hefeng39 to imazethapyr was higher than Heinong40's and Suinongl4's.The results of the field experiment showed that the injury of residue imazethapyr in soilto aftercrop was serious. The dosage of imazethapyr was less than 150g a.i. /hm2, corn and wheat could be sowed after 12 months, and potato could be sowed after 24 months in the field. When the dosage range of imazethapyr was 75-150g a.i. /hm2, the injury of residue imazethapyr to rape, sugar beat and Chinese cabbage was very heavy still, they could not be sowed after 24 months.We ascertained the mechanism elementarily that active carbon, NA and Penatron alleviated the injury of residue imazethapyr to aftercrop. When the residue dosage of imazethapyr was less than 6.25g a.i./hm2, seed treatment solution with active carbon and soil treatment with Penatron could alleviate injury of residue imazethapyr in soil, but soaking of seed with NA couldn't protect sugar beat and rape from injury.The injury of residue imazethapyr to aftercrop is been urgent with us to settle. The protectants could protect aftercrop from injury, none but, when the residue imazethapyr was less. So reducing dosage of imazethapyr plays an important role in alleviating injury of residue imazethapyr to aftercrop. The result of field experiment indicated that there were synergism when imazethapyr mixed with YZ-901 and AA-921, and its dosage was reduced. In the same control efficacy, right amount adjuvant could reduce 40% dosage of imazethapyr. Imazethapyr mixed with Vernam7-E and Trifluralin and as preplant soil treatment, mixed with Clomazone, Acetochlor and Metolachlor as preemergence soil treatment, and mixed with Flumiclorac-pentyl, Sethoxydim, Fomesafen, Clomazone and Acifluorfen sodium as postemergence foliar treatment could broaden its weed control spectrum and redu... |
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