Abstract: Cu and Zn are popularly used as additives in animal feed in China,which could result in their excessive accumulation in manure to a toxic level,and thus,possibly threaten the environment when the manure is applied to farmland.In this paper,the acute and sub?acute lethal effects of pig manure with excessive Cu and Zn on earthworm were studied,and the results indicated that the concentration of Cu and Zn in pig manure had a significantly positive correlation with the mortality of earthworm,while a significantly negative correlation with earthworm growth rate.The individuals of earthworm had different tolerance to excessive Cu and Zn,with the threshold values causing death being 250 mg·kg^-1 and 400 mg·kg^-1 for Cu and Zn,respectively.The LD50 was 646.68 mg·kg^-1 for Cu,and 947.38 mg·kg^-1 for Zn.A strong synergistic effect was observed under the combined pollution of 250 mg·kg^-1 for Cu and 500 mg·kg^-1 for Zn,whereas antagonistic effect happened when 750 mg·kg-1 for Cu was supplied, suggesting that the joint toxic effects of Cu and Zn on earthworm were closely correlated to their concentrations in pig manure.

Key words: Trifolium repens, Cutting, Energy allocation, Architecture