Evaluation of Organic and Inorganic Amendments on Maize Growth and Uptake of Cd and Zn from Contaminated Paddy Soils

Pot and field experiments were conducted to investigate the effects of soil amendments (cow manure, rice straw, zeolite, dicalcium phosphate) on the growth and metal uptake (Cd, Zn) of maize (Zea mays) grown in Cd/Zn contaminated soil. The addition of cow manure and rice straw significantly increased the dry biomass, shoot and root length, and grain yield of maize when compared with the control. In pot study, cow manure, rice straw, and dicalcium phosphate all proved effective in reducing Cd and Zn concentrations in shoots and roots. Cd and Zn concentrations in the grains of maize grown in field study plots with cow manure and dicalcium phosphate amendments to highly contaminated soil (Cd 36.5 mg kg⁻¹ and Zn 1520.8 mg kg⁻¹) conformed to acceptable standards for animal feed. Additionally both cow manure and dicalcium phosphate amendments resulted in the significant decrease of Cd and Zn concentrations in shoots of maize.