四川省小麦田不同耕作方式下杂草的发生规律及防治

连续2年对3种不同耕作方式下小麦田杂草的发生规律和防治进行研究,结果显示,四川省小麦田在3种不同耕作方式杂草发生的种类差异不大,主要有5科7种,翻耕处理杂草数量最多,其次为免耕不覆盖稻草处理,免耕覆盖稻草处理杂草最少.在同一耕作方式下,小麦生长前期的杂草最多,生长中期居中,生长后期最少.免耕不覆盖稻草处理的优势杂草为禾本科杂草＋繁缕,免耕覆盖稻草处理和翻耕处理优势杂草为繁缕＋禾本科杂草.杂草的发生高峰期集中在播后2～4周,占整个生育期的70％～ 80％.免耕覆盖稻草小麦的产量较免耕不覆盖稻草和翻耕产量高,翻耕和免耕不覆盖稻草差异不大.通过药剂筛选可知,炔草酯可有效防除禾本科杂草（棒头草和看麦娘）;2甲·唑草酮和唑草酮都能有效防除繁缕、通泉草、碎米荠,2甲·唑草酮比唑草酮杀草谱宽,效果更好;2甲·氯氟吡和氯氟吡氧乙酸能有效防除繁缕、通泉草,2甲·氯氟吡比氯氟吡氧乙酸杀草谱宽,效果更好;苯磺隆对繁缕、碎米荠防效优良,对通泉草、扬子毛茛防效较差.

Weed Occurrence and Control by Different Tillage Methods in Wheat Fields in Sichuan Province

Weed occurrence and control by three different tillage methods was studied for two years.Tillage method did not affect the species of weeds present,which included seven species belonging to five families.Tilled fields had the highest weed densities,followed by those with the no-tillage treatment;the fields with a cover of straw had the lowers densities.Within any tillage method,the greatest number of weed occurred during the early growth of wheat,decreasing with the growth of the crop.Gramineae and chickweed were dominant in fields under no-tillage,while in those that were till or straw covered chickweed and Gramineae were prevalent.Most of the weeds occurred during 2 ～4 weeks after wheat sowing,which accounted for 70％ ～ 80％ of the whole growing period.Wheat yidd was higher in the no-till plots than in the other two treatments,which did not differ from each other.Clodinafop propargyl effectively controlled Gramineae,and MCPA-Na carfentrazone-ethyl and carfentrazone-ethyl effectively controlled ckickweed,Japanese Mazus and Pennsylvania Bittercress,but the effect of MCPA-Na carfentrazone-ethyl was superior to carfentrazone ethyl.MCPA fluroxypyr-meptyl and fluroxypyr meptyl also effectively controlled ckickweed and Japanese Mazus,with the mixture of MCPA fluroxypyr-meptyl being much better.Finally,tribenuron-methyl was effective against ckickweed and Pennsylvania Bittercress but poorly controlled Japanese Mazus and Siebold Buttercup.