小麦连作、迎茬和轮作对麦田杂草群落的影响

通过定位试验,研究了小麦8-12年长期连作、小麦-大豆-小麦迎茬和玉米-大豆-小麦轮作条件下麦田杂草群落变化。结果表明,小麦长期连作区杂草密度最大,杂草最多,小麦-大豆-小麦迎茬次之,玉米-大豆-小麦轮作杂草最少。小麦-大豆-小麦迎茬和玉米-大豆-小麦轮作区之间差别小于两者与连作区的差别。3种茬口杂草密度、杂草数量顺序为连作区＞小麦-大豆-小麦迎茬＞玉米-大豆-小麦轮作。随着连作年限的增加,小麦连作区一些杂草种类增加,同时也有些杂草种类减少。小麦连作10年增加的杂草有龙葵、鸭趾草、鬼针、苋及野苏,连作12年增加的杂草有问荆、扁竹菜和猪秧秧,而减少了龙葵、鬼针、野苏和苣荬菜。小麦连作区主要杂草为藜、龙葵、荠、稗、鬼针、鸭趾草和卷茎蓼。

Effects of wheat rotation and monocropping system on weed populations in wheat fields

This experiment has been conducted in Hailun Agricultural Ecological Experiment Station,CAS since 1991 with different site-specific rotation systems including wheat monocropping (WWW), wheat-soybean-wheat intercropping (WSW),and com-soybean-wheat intercropping (CSW). The results of the site-specific field experiments showed that weed density and fresh weight were the highest in WWW,followed by those in WSW and CSW. In different years the weed populations were different in the same plots. Some weeds appeared in WWW but not in WSW and CSW, while other weeds didn' t appear in WWW.