化学除草对麦田杂草群落结构的影响

１９９３－１９９７和磺酰脲类除草剂进行麦田化学除草试验。结果表明，所使用的除草剂均能有效地防治阔叶杂草，如播娘蒿，荠莱，糖芥等，除草效果大于９０％。麦杂草种类的演变为今后进行麦田化学除草提出新的课题。

EFFECT OF CHEMICAL CONTROL ON WEED CROWUNITY IN WHEAT FIELDS

The experiments on suifonylurea herbicides were conducted in wheat fields from 1993 to 1997. All herbicides studied could control the broad-leaved weed such as Descurainia sophia(L. ) Schur,Capsella bursa-p asterisk. )Medic and Erysimum cheiran-thoides L. and had more than 90 percent of controlling effect. The use of of suifony-lureas herbicides year by year caused the shift of the weed community. Once the dicotyledonous weeds, mainly Descurainia sophia (L. ) Schur had been prevalent in the field,gradually the community was changed into a mixture of the monocotyledonous and dicotyledonous weeds in which both Bromus japonicus Thunb and Descurainia sophia (L. ) Schur were dominant. The population of Bromus japonicus Thunb increased year after year and its density went up from 0. 1 - 0. 4 plants m-2 to 31. 5 - 78. 5 plants m-2 while Descurainia sophia (L. )Schur decreased from 78. 3~ 176. 4 plants m-2 to 33. 3 - 53. 2 plants m-2. This phenomenon gave a new subject for the future chemical control in wheat fields.