南方典型稻区稻米镉累积量的预测模型研究

为了更好地指导镉污染稻田土壤修复、管控稻米镉风险,本文以我国镉污染风险较大的南方稻田为研究对象,基于土壤与稻米配对样品,分析稻米镉含量与土壤理化因子的相关关系,并通过逐步回归分析,建立稻米镉累积量的预测模型。结果表明,我国南方稻区稻米镉累积量主要取决于土壤有效态镉含量而非全镉含量,有效铁、有效锰及有机质含量也是影响稻米镉含量的重要因素;在不考虑水稻品种条件下,采用土壤有效态镉含量、有效锰、有效铁及有机质可较好预测稻米镉积累量,模型的预测能力达到极显著水平(P0.001),决定系数(R2)为0.52;针对常规稻和杂交稻,以上述4个土壤因子分别建立的模型也可实现较好预测(P0.001),R2分别为0.47和0.67。

Prediction model for the accumulation of cadmium in rice in typical paddy fields of south China

Cadmium(Cd) pollution in paddy soil is an increasingly serious problem in southern China. Establishing a prediction model for the accumulation of Cd in paddy rice is of great significance to guide the remediation of Cd-contaminated paddy soils and control the risk of Cd pollution. To construct simulation models of Cd accumulation in paddy rice for southern China, 90 pairs of soil and brown rice samples were collected from typical paddy fields in Hunan Province. The concentrations of Cd in brown rice, total Cd, CaCl₂ extractable Cd in soil, and basic soil properties were determined. Further, the relationships between Cd concentration in rice and soil properties were analyzed using correlation analysis and stepwise regression. The results indicated that the concentrations of Cd in brown rice were mainly related to the available Cd content rather than the total Cd content in paddy soils. Moreover, the presence of available iron(Fe), manganese(Mn), and organic matter in soil, and the varieties of paddy rice also played important roles in Cd accumulation in brown rice. The simulation model of Cd accumulation in brown rice based on available Cd, Mn, Fe, and organic matter in soils showed high accuracy(P<0.001, R²=0.52) independent of rice variety. Furthermore, simulation models based on the above four soil factors could also predict the accumulation of Cd in conventional rice varieties(P<0.001, R²=0.47) and hybrid rice varieties(P<0.001, R²=0.67).