除草次数对杂草群落和夏玉米产量的影响

以山东省沂蒙山区夏玉米田为研究对象，设化学除草剂除草（CK）、不除草（W0）、苗期人工锄草1次（W1）、苗期+开花期人工锄草两次（W2）4种处理方式，研究除草次数对农田杂草生物多样性和对夏玉米产量的影响。结果表明，玉米田中9种杂草的多样性指数以W0处理最高，W1处理次之；花后40 d，W1、W2处理玉米地上部生物量与CK差异不显著（P>0.05），W0处理与CK差异显著（P<0.05）；产量也表现出相同规律。研究表明，当地苗期适时进行1次除草，不仅能维持杂草多样性，而且可避免作物产量损失；与人工锄草两次相比，1次除草能省工省时，减少成本。

Effects of Differential Weed Times on Weed Community, Yield of Summer Maize

Weeding by herbicides at seedling stage(CK), no weeding(W0), manual weeding once at the stage of seedling(W1), manual weeding twice at the stage of seedling and anthesis(W2) had been applied to summer maize in a temperate cropland of Shandong province, aimed to study their influences on the changes of diversity indexes of weeds and yield of summer maize. The results showed that there were 9 kinds of weeds in local cornfield. The total density and diversity index of weeds of W0 were significantly higher than others, W1 ranking the second. 40 days af-ter flowering, the aboveground biomass of maize of W1, W2 displayed no significant differences with CK(P>0.05), but W0 showed significant differences with CK(P<0.05); the yields showed a similar tendency to the aboveground biomass. The economic benefits of CK showed the highest. W1, W2 were respectively only 7% and 10% lower than CK. It showed that weeding once duly can hold weed diversity and avoid yield loss. Compared with W2, weeding once can also save labor, time and cost.