化学除草剂对农田生物群落的影响

从直接作用和间接作用两个方面,在个体、种群和群落3个水平上综述了化学除草剂对农田植物、动物和微生物群落的影响,并提出了今后需要加强研究的几个问题(1)残留在作物和杂草植株内的除草剂及其代谢产物通过食物链和生物富集作用对农田动物群落各级消费者造成的影响;(2)非作物生境使用化学除草剂对毗邻作物生境天敌群落的影响,以及作物生境使用除草剂对邻近非作物生境天敌群落的影响;(3)由除草剂长期使用引起的杂草群落演替、多样性下降、地表覆盖物和地下生物量减少对土壤动物和微生物群落的物种组成、分布、丰富度及其生态功能的影响;(4)化学除草剂与杀虫剂和化肥等其他农用化学品对农田生物群落的联合作用。

Effects of chemical herbicides on bio-communities in agroecosystems

The existing literature was reviewed to address the direct and indirect effects of chemical herbicides on the bio-communities in agroecosystems. Continual use of chemical herbicides may bring about the resistance of weeds to herbicides, accelerate the succession and decrease the biodiversity of the weed community. If abused, herbicides might change the biochemical composition of the crops, affect the nitrogen metabolism and the crop's resistance to pests and diseases, aggravate or alleviate plant diseases and insect pests, and cause serious damage to crops. The direct effects of herbicides on animals and microorganisms vary with the type and concentration of the herbicides, as well as, the type and developmental stages of the organisms. Moreover, the direct effects of herbicides on the crops and non-crop plants will cause a series of changes on the associated fauna and microorganisms. Most of the direct and indirect effects have been interpreted as negative from ecological and sustainable points of view. The following subjects are suggested for further study: (1) How might the residual herbicides and their metabolites left in crops and weeds effect all trophic levels of fauna in the fields via food chains and bioaccumulation; (2) How might herbicides used in non-crop habitats impact the neighboring plants and associated fauna, and vice versa; (3) What might the changes in the weed community, as well as, the decrease of diversity, earth-surface shroud and the underground biomass be, due to prolonged application of herbicides, which might induce impacts the composition, distribution, abundance and eco-function of the bio-communities in the soil; (4)What might the combined effects of herbicides and other agricultural chemicals be on the flora, fauna and microorganism in agroecosystems.