影响不同农作物镉富集系数的土壤因素

农作物的Cd富集系数（BCF）受多种因素影响.为明确田间条件下不同农作物的Cd富集系数特征差异及土壤性质对其影响，分别在我国水稻、小麦和玉米主产区不同污染程度的地块上作物收获期采集土壤和作物籽粒点对点样品，研究水稻、小麦、夏玉米和春玉米的Cd富集系数特征及土壤性质对不同农作物的Cd富集系数的影响，并通过多元回归方程建立以上农作物Cd富集系数与土壤性质的定量关系.结果表明，在田间土壤中Cd含量范围为0.15~2.66 mg·kg^-1条件下，水稻、小麦、夏玉米和春玉米Cd富集系数的均值分别为0.915、0.155、0.113和0.102，水稻明显高于小麦和玉米，春玉米的Cd富集系数最低.土壤中的Cd含量与小麦、夏玉米和春玉米的BCF呈极显著负相关；土壤有机质（SOM）与小麦、夏玉米BCF之间的关系呈极显著负相关；土壤pH和阳离子交换量（CEC）对作物BCF也有影响.引入土壤Cd含量、pH、SOM、CEC等因素，建立水稻、小麦、夏玉米和春玉米的Cd富集系数预测方程.水稻、小麦、夏玉米和春玉米的BCF预测方程相关系数分别为0.423^*、0.796^**、0.826^**和0.551^**，均达到显著或极显著水平，可以较好地预测不同土壤条件下不同农作物的BCF值.

Influencing Factors of Cadmium Bioaccumulation Factor in Crops

The Cd bioaccumulation factor (BCF) of crops is affected by many aspects. In order to clarify the differences in the Cd bioaccumulation factor characteristics of different crops under field conditions and the influence of soil properties, point-to-point samples of soil and crop grains were collected during crop harvesting on plots with varying pollution levels in the primary production areas of rice, wheat, and maize in China. The characteristics of the Cd bioaccumulation factors of rice, wheat, summer maize, and spring maize and the effects of soil properties on the Cd bioaccumulation factors of different crops were studied, and the quantitative relationship between the Cd bioaccumulation factors and soil properties was established through multiple regression equations. The results revealed that the average BCF values of Cd in rice, wheat, summer maize, and spring maize were 0.915, 0.155, 0.113, and 0.102, respectively, with the Cd content in the field soil of 0.15-2.66 mg·kg^-1. Rice is significantly higher than wheat and maize, and spring maize has the lowest Cd bioaccumulation factor. The Cd content in the soil is extremely negatively correlated with the BCF of wheat, summer maize, and spring maize. The relationship between soil organic matter (SOM) and the BCF of wheat and summer maize demonstrated a significant negative correlation. The soil pH and cation exchange capacity (CEC) also affect the BCF of crops. Introducing the soil Cd content, pH, SOM, CEC, and other factors, the Cd bioaccumulation factor prediction equations of rice, wheat, summer maize, and spring maize were established. The correlation coefficients of the BCF prediction equations for rice, wheat, summer maize, and spring maize are 0.423^*, 0.796^**, 0.826^**, and 0.551^**, respectively. The above models reached significant or extremely significant levels, which can better predict the BCF value of different crops under varying soil conditions.