Effects of chemical herbicides on bio-communities in agroecosystems
HUANG Ding-Cheng, YOU Min-Sheng, HOU You-Ming, LI Zhi-Sheng (Institute of Applied Ecology, Fujian Agriculture and Forestry University, 350002, China).
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.