百草枯的控草效果及对光照和油菜产量的影响

为明确百草枯在免耕油菜田的应用前景,建立免耕油菜田的杂草管理体系,研究了百草枯对免耕油菜田杂草的控制作用及该药剂对田间光照和油菜产量的影响.结果表明,百草枯对免耕油菜田杂草具有较好的防除效果,药后第5d的总体防效在98.50%～99.49%之间,药效随时间的延长略有下降,160d内的控草效果仍可达85%以上.百草枯对田间主要杂草看麦娘(Alopecurus aequalis)、牛繁缕(Malachium aquaticum)及菵草(Beckmannia syzigachne)的防除效果较好,对通泉草(Mazusjaponicus)的效果较差.使用百草枯能显著提高油菜田间的透光率,随着用药量的增加,透光率逐渐上升.百草枯的施用对油菜株高、千粒重没有显著影响,但对油菜第一分枝高度、单株分枝数、角果数影响较大,能显著提高油菜产量.

Weed control effect of paraquat in untilled fields and its influence on the light and yield of rapeseed

The weed control effects of paraquat and subsequent dynamics in untilled rape fields,as well as the influence of paraquat on the sunlight and crop yield were studied to evaluate the application prospect of paraquat and establish a weed management system in untilled rapeseed fields.The results showed that paraquat provided good control effects on weeds in untilled rapeseed fields,the overall effects ranged from 98.50% to 99.49% five days after treatment(DAT),decreased and maintained above 85% for 160 DAT with graduall decrease.The efficacy was higher on Alopecurus aequalis,Malachium aquaticum and Beckmannia syzigachne,than on Mazus japonicus.Paraquat application significantly improved the light conditions in rapeseed field and the light penetration rate increased with the dosage of herbicide.The application of paraquat had no effect on the plant height and 1000-seed weight,whereas the height of first branch,numbers of branches and siliquae were markedly influenced,resulting in a significant yield increase of rapeseed.