Abstract:Since organoarsenicals, copper and zinc additives are widely used in modern intensive animal production, animal manures are commonly high in As, Cu and Zn content. A pot experiment with amaranth was conducted to investigate As, Cu and Zn bioavailability in a paddy soil (PS) and a lateritic red soil (LRS) applied with 2% and 4% (w/w) chicken manure (CM) and pig manure (PM), respectively. Soils without any fertilizer were included as the checks (CK). Results show that application of the two manures increased biomass of the shoots of amaranth, but decreased its As, Cu and Zn content. Variation of the contents of As, Cu and Zn and uptake rates of three elements in amaranth among treatments with manures didn’t show any distinct rule two soils. However, though the initial contents of total and available As, Cu and Zn were much lower in LRS than in PD, As, Cu and Zn contents and As, Zn uptake rates of amaranth were significantly higher in LRS than in PD at the level of 0.01, with the exception that significant difference wasn’t observed in Cu uptake rates between two soils. Soil total and available As in all treatments reduced after the harvest of amaranth, but soil total and available Cu and Zn increased in treatments applied with higher rates of two manures as compared to their initial values. And, soil total and available As, Cu and Zn and percent available As, Cu and Zn over total As, Cu and Zn increased by the application of manures compared to CK. It was assumed that the bioavailability of heavy metals be measured by the increments of available content and percent available content over total content, availability of soil As was enhanced by CM than by PM, but that of soil Cu and Zn was increased by PM than by CM. The availability of soil As, Cu and Zn was higher in treatments with higher manure rates than those with lower ones, and higher in LRS than in PS.