Abstract
A cultivation experiment was conducted to investigate the change of chemical forms of Cu, Fe, and Zn in compost produced from horse dung (HDC) and that produced from swine manure (SMC). A mixture of silica gel and sieved HDC and that of silica gel and sieved SMC were used as media to cultivate peas (Pisum sativam L.) in order to determine bioavailable chemical forms of Cu, Fe, and Zn. Cu and Fe were primarily found in an organic complex fraction and residue fraction of HDC and SMC. Zn was primarily found in an iron and manganese oxide fraction and an organic-complex fraction. There was little change in the concentration of “bioavailable fractions,” such as water-soluble, exchangeable, and carbonate. However, the amount of Cu and Fe in the organic complex fraction decreased significantly and that Zn in the iron and manganese oxide and organic complex fractions also decreased significantly. These results indicated that the transportation of Cu, Fe, and Zn to plants affected their chemical forms. The associated fraction played a role in the storage (sink) of Cu, Fe, and Zn when the amount decreased significantly.
