Morphological Pattern of Heavy Metal Zn in Soil and Its Driving Factors During Rice-Rapeseed Rotation

Abstract

To study the speciation characteristics of soil Zn and its distribution in different tillage layers during paddy and drought rotation. Taking the cultivated soil under rice-rape rotation in Bozhou District, Zunyi City, Guizhou Province as the research object, the speciation characteristics and driving factors of soil Zn during rice-rape rotation were studied. In the process of rice-rape rotation, the total amount of heavy metal Zn in surface soil was greater than that in bottom soil. In the depth of 0-40 cm soil layer, the exchangeable fraction of Zn in soils was small, and residue fraction was the greatest. The exchangeable fraction of Zn in surface soils was positively correlated with carbonate bounded fraction and iron-manganese oxide bounded fraction, and negatively correlated with residue fraction. While the exchangeable fraction of Zn in bottom soil was positively correlated with iron-manganese oxide bounded fraction and organic bounded fraction, and positively correlated with residue fraction. During rice-rape rotation process, the content of Zn showed a significant surface aggregation, and was affected by different forms and contents.