Behavior of Zinc and Copper in Soil with Long Term Application of Sewage Sludges

Abstract

Two kinds of sewage sludge composts were applied separately to a crop field consisting of volcanic ash soil (Andosoil) twice a year at 10 t/ha for 12 years since 1978 and the changes in the concentrations of total and soluble Zn and Cu in the sewage sludge-treated soil were studied. The total amount of Zn in the surface soil of the sewage sludge-treated plots increased year by year. The total Zn concentration in the subsoil of these plots was higher than that of the non-treated plot after 12 years of application of the sewage sludge. Cu accumulated somewhat in the surface soil, but not in the subsoil during this period. These facts suggest that Zn moved down to about 20 cm in the Andosoil within 12 years. Sewage sludge application increased the ratio of soluble Zn to total Zn in both the surface soil and subsoil during a 9 year period. © 1992, Japanese Society of Soil Science and Plant Nutrition. All rights reserved.