| Chemical control is the main way to controlweeds in rice stubble wheat field.Formula screening of new herbicide mixtures and it's application techniques were studied in this thesis according to the occurance law of weeds in wheat field of Jiangsu Province.The control effects of different herbicides and the best herbicide mixtures were studied through whole plant bioassay in greenhouse.After formula screening,the application techniques of new herbicide mixture were investigatied through greenhouse bioassay and field experiments.Then,the safety and control effects of new herbicide mixture were investigatied in rice stubble wheat fields at different place in Jiangsu Province.Results obtained were listed as following:1.The study of halosulfuron-methyl mixture with pretilachlor and isoproturonThe sensitivity of Alopecurus japonicuss and Vivia sativa,which was the main weeds in rice stubble wheat fields,to different commonly used herbicides were determination.According to the principles of expanding kill-weeding table,reducing the costs and increasing the effects,the co-toxicity coefficient method was used to filter the proportions of halosulfuron-methyl,pretilachlor,and isoproturon were 1.5:14:34.5 and 1.5:16:29.5.The cotoxicity coefficient was more than 120,showed a synergistic effect.In this study,we chose the mixture 1.5:16:29.5 to develop and product the mixed herbicide.2.The safety of 47%halosulfuron-methyl-pretilachlor'isoproturon WP to wheat47%halosulfuron-methyl-pretilachlor-isoproturon WP 1350-4500 g a.i./hm2 was safety to different varieties of wheat when preemergence applied.The plant height,tiller number,fresh weight of wheat had no significant difference comparing with the conventional treatment when 47%halosulfuron-methyl.pretilachlor.isoproturon WP 1800?4500 g a.i./hm2 were applied at different leaf stage,artificial precipitation after treated with herbicides,didn't cover the soil after sowing,cultured in different soil conditions or encountered low-temperature.3.The spectrum of weeds control of 47%halosulfuron-methyl·pretilachlor·isoproturon WP20 days after preemergence application or applicated when the weeds at 2-3 leaf stage,the control effects of 47%halosulfuron-methyl·pretilachlor·isoproturon WP(1350?4500g/hm)on Beckmannia syzigachne,Alopecurus japonicuss,Alopecurus aequalis Sobo.,Sclerochloa keniana(Ohwi)Tzvel.,Poa annua L.,Stellaria media(L.)Cyr.,Capsella bursapastoris,Vicia sativa and Geranium carolinianum L.were 91.66%?100%,but the control effect on Galium aparine L.vartenerum(Gren.etGodr.)Rehb.was poor.The control effect of 47%halosulfuron-methyl·pretilachlor·isoproturon WP preemergence application on weeds was better than application at 2-3 leaf stage of weedd at the same doses.4.Efficacy and safety of 47%halosulfuron-methyl-pretilachlor-isoproturon WP in the field test.The plant height,tiller numbe,fresh weight,effective panicle,grain number per panicle and theoretical grain yield of wheat in plots after treated with 47%halosulfuron-methyl·pretilachlor·isoproturon WP at 1057.5 and 1903.5 g a.i./hm2 before wheat emergence were similar with the artificial weeding,and the control effects on B.syzigachne,Stellaria media(L.)Cyr.and Capsella bursapastoris were very well.5.Efficacy and safety of 47%halosulfuron-methyl-pretilachlor-isoproturon WP applied at different conditions in the field.In the field test,preemergence application of 47%halosulfuron-methyl·pretilachlor·isoproturon WP 2400?8100g/hm2or sprayed at 1,5-2 leaf stage of wheat were safe to wheat,and the effect on B.syzigachne,Stellaria media(L.)Cyr.and Capsella bursapastoris were more than 90%.Application of 47%halosulfuron-methyl·pretilachlor·isoproturon WP at different conditions could be used to control B.syzigachne,S.media,C.Bursapastoris.6.Efficacy and selectivity of 47%halosulfuron-methyl·pretilachlor·isoproturon WP in the field demonstrtion.The results of the field experiments at different place indicated that preemergence application of 47%halosulfuron-methyl-pretilachlor-isoproturon WP at the doses of 2250g/hm2 and 3000g/hm2 had no effect on wheat,which can effectivety control the weeds in rice stubble wheat of the resistant B.syzigachne,A.japonicuss,A.aequalis Sobo.,P.annua L.,S.keniana(Ohwi)Tzvel.,P.fugax Nees ex Steud.,S.media(L.)Cyr.,M.aquaticum(L.)Fries.et al.The control effects of 47%halosulfuron-methyl pretilachlor isoproturon WP on G.aparine L.var.tenerum(Gren.et Godr.)Rehb.was varied in different places. |
PDF Full Text Request