Transfer Characteristics of Cd in Paddy Soil-Rice System under Field Condition

Abstract

It is important to control Cadmium (Cd) content in rice and ensure the grain security. The transfer characteristics of Cd in paddy soil-rice system between different soil types (red soil and purple soil) under field condition were researched to provide a theoretical basis for Cd environmental management in paddy. In this study, many rice plant samples and corresponding paddy soil samples were collected from fields around the industrial and mining area in central Hunan province in 2011 and 2012. The Cd concentration of samples was analyzed, and the degree of Cd contamination was evaluated. Moreover, the differences of enrichment factor and influencing factors in paddy soil-rice system between red soil and purple soil were discussed. The results revealed that paddy soils and brown rice in the survey area were serious contaminated by Cd. The Cd content and enrichment factor were arranged in the order of root> straw >chaff >brown rice. The Cd content and enrichment factor were in the order of red soil >purple soil. In addition, multivariate linear regression was analyzed and predictions models of Cd concentration of brown rice are based on different types of soil were worked out. It showed that total Cd of soil, organic matter and clay were the main factors that affecting the content of Cd in brown rice. In conclusion, the contamination characteristics, transfer disciplinarian and influencing factors of Cd in the soil-rice system are different between red soil and purple soil. So it needs to pay more attention to the characteristics of different soil parent material when making environmental management related to Cd contamination in soil-rice system.