Modulation Effects of CaCO_3 on Cd and Some Nutrient Elements in the Red Soil-Soybean System

Modulation effects of CaCO3 application on Cd migration and distribution in a red soil-soybean system and on changes in contents of several nutrient elements in this system were studied through a pot experiment.The results indicated that CaCO3 application enhanced pH values and exchangeable Ca contents in the soils,and significantly reduced soil exchangeable Cd contents,so that adsorption and transfer of soil Cd to soybean plants were effectively reduced.Therefore,CaCO3 application could be used to remedy Cd polluted soils.With increasing in applied amounts of CaCO3,contents of exchangeable K,Mg,Zn,Mn in soils and those elements in soybean leaves decreased.Due to decreasing activity of soil Cd,CaCO3 application effectively restrained movement of Cd from the under-earth to the over-earth in the red soil-soybean system,significantly decreased Cd contents in different organs of soybean plants.However,people should pay attention to the phenomena of decrease of nutrient elements in soybean leaves caused by CaCO3 application.