金衢盆地典型地区土壤-稻米重金属含量及土壤酸碱度的影响研究

作物对土壤中重金属的吸收受作物种类、采集部位及土壤理化性质等多方面因素的影响。近年来，金衢盆地土壤酸化面积逐年增大，酸化程度逐渐加深，其对土壤-作物系统中重金属元素的活动影响尚不明确。本文基于金衢盆地典型地区264组根系土壤-稻米样品分析数据，开展土壤、作物的重金属含量特征及其影响因素的研究，重点讨论了土壤pH对作物吸收重金属的影响。结果表明：①264件土壤中多数重金属元素的变异系数大于0.5，As、Cd、Cr、Cu、Ni和Zn元素之间呈显著正相关（P<0.01）。土壤Cd超标样品23件，超标率为8.7%；As、Cr、Cu、Hg、Ni、Pb和Zn超标样品均未超过2件。②稻米中Cu、Zn与Cd含量呈显著正相关，Cd的富集系数（BCF）高于植物营养元素Cu、Zn。③稻米中Zn和Cu在P<0.1水平上与pH值呈显著正相关。Cd、Cr、Hg的BCF与pH值之间存在一定的负相关性。研究认为，适当调低土壤的酸碱度会削减土壤中Cd、Hg等重金属元素的活性，从而减少农作物对重金属的吸收转运。研究结果可为当地粮食安全生产决策提供科学数据，为土地管护提供参考依据。

Concentration of Heavy Metals in Soils and Rice and Its Influence by Soil pH in Jinqu Basin

BACKGROUND: The absorption of heavy metals in soil by crops is affected by various factors such as crop types, collection sites and physical and chemical soil properties. In recent years, soil acidification of an area in the Jinqu Basin has increased year by year, and the degree of acidification has gradually deepened.OBJECTIVES: In order to find out the content characteristics of heavy metals in soil and crops, the influence of soil acidification on the absorption of heavy metals by crops was studied.METHODS: Based on 264 samples of root soil-rice samples from a typical area of the Jinqu Basin, the characteristics and influencing factors of heavy metal content in soil and crops were studied.RESULTS: The results showed that:(1) The variation coefficient of most heavy metal elements in 264 soil samples was greater than 0.5. Significant positive correlations (P<0.01) occurred among the elements of As, Cd, Cr, Cu, Ni, and Zn in soil. 23 soil samples of Cd exceeded the standard, and the over-standard rate was 8.7%. The soil samples number of other elements(As, Cr, Cu, Hg, Ni, Pb and Zn) exceeding the standard were no more than 2. (2) The contents of Cu, Zn and Cd in rice were positively correlated, and the enrichment coefficient of the toxic heavy metal element Cd was higher than that of plant nutrient elements Cu and Zn. (3) Zn and Cu in rice were positively correlated with soil pH at P<0.1. Bioconcentration factor (BCF) of Cd, Cr and Hg were negatively correlated with pH.CONCLUSIONS: It is believed that adjusting soil acidity will reduce the activity of Cd, Hg and other heavy metal elements in the soil, in order to achieve the goal of minimizing the absorption and transport of heavy metal elements in crops. The research results provide scientific data for local food production safety decision and reference for land management and protection.