CaCO_3对Cd和几种营养元素在红壤-黄豆系统中的调控作用

利用盆栽试验,通过研究CaCO3施用对Cd在红壤-黄豆系统中的迁移与分配和对几种营养元素在土壤以及黄豆叶片中含量变化的影响,探讨了CaCO3对Cd和几种营养元素在红壤-黄豆系统中的调控作用。结果表明,CaCO3施用能提高土壤pH值和交换态Ca含量,显著降低土壤交换态Cd含量,有效抑制黄豆植株对Cd的吸收和转运,从而达到修复土壤Cd污染的目的。同时,随着CaCO3施用量的增加,土壤交换态K,Mg,Zn,Mn等营养元素含量下降,黄豆叶片中这些元素含量也同时降低。CaCO3施用虽然能够降低土壤Cd的活性,有效抑制土壤Cd向植物地上部分迁移,显著降低黄豆各器官的Cd含量,但是黄豆叶片中营养元素含量下降的现象应该引起人们的注意。

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.