玉米连作、迎茬和轮作对田间杂草群落的影响

Effects of corn rotation and continuous cropping system on weed population

采用定位试验方法研究了北方旱作玉米长期 (1 0～ 1 2年 )连作、米豆米迎茬和豆麦米轮作条件下玉米田杂草群落变化。结果表明 ,3种茬口杂草密度以米豆米迎茬最小 ,杂草密度在不同年际间存在着差异 ,随着连作年限的增加 ,使连作区一些杂草种类增加 ,同时也有些杂草种类减少 ,但这种差别主要是在双子叶杂草之间 ,单子叶杂草种类没有变化 ,如连作 1 2年较连作 1 0年杂草增加了牛繁缕 ,减少了鸡眼草。 2年调查结果可知 ,连作、迎茬和轮作 3个茬口相比 。

This experiment was conducted in Hailun Agriculture Ecological Experiment Station in northeastern China ,CAS, since 1991, with site specific different rotation systems including continuous corn (C C C……C),corn soybean corn(C S C),and rotation(soybean wheat corn,S W C).The results showed that the weed density and weed fresh weight were the least in CSC .In different years, the weed population were different at the same plots .Weed species were more in C C C……C plot than in S W C and C S C plots.For example, Kummerowia stipulacea only occured in C C C……C plot but did not occur in S W C and C S C plots in 2000. Malachium aquatium only appeared in C C C……C plot but did not occur in S W C and C S C plots in 2002.Some weed population appeared in C C C……C except C S C and S W C.But in some year, some weed disappeared in C C C……C.