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通过采集南宁市郊农田中玉米、蔬菜、水稻可食部分及其根系土150组,研究重金属元素在不同土壤-农作物系统中迁移特征及其影响因素,结果表明:土壤中Hg、Cd、Cr、Cu、Ni、Pb、Zn平均含量分别为0.116、0.202、56.76、22.12、14.49、25.18和56.28 mg·kg-1。农作物对应平均含量分别为0.0011、0.037、0.054、1.153、0.205、0.011和9.37mg·kg-1。根系土富集因子表明Cd受到不同程度人为活动影响,Cr和Ni主要受地质背景控制;不同作物系统元素富集因子表明Pb在土壤-农作物系统中迁移能力最低,Zn迁移能力最强。Cd、Cr、Cu、Ni、Pb和Zn在土壤-水稻系统重迁移能力显著高于蔬菜和玉米。土壤中pH、CaO、有机质、Fe2O3、K2O、MgO与重金生物富集系数呈显著性负相关,但在土壤-叶类蔬菜系统中土壤中K2O、MgO与Hg生物富集系数呈显著正相关。
The characteristics and influencing factors of heavy metal elements migration in different soil-crop systems were studied by collecting 150 edible corn roots, vegetables, edible parts of rice and their root soils in the suburbs of Nanning. The results showed that the contents of Hg, Cd, Cr, Cu , Ni, Pb and Zn were 0.116,0.202,56.76,22.12,14.49,25.18 and 56.28 mg · kg-1, respectively. The corresponding average crop yields were 0.0011,0.037,0.054,1.153,0.205,0.011 and 9.37 mg · kg -1, respectively. The enrichment factor of root soil indicated that Cd was affected by anthropogenic activities to varying degrees. Cr and Ni were mainly controlled by the geological background. The enrichment factor of Pb in different crop systems indicated that Pb had the lowest migration ability and the strongest Zn migration ability in soil-crop system. The heavy migration ability of Cd, Cr, Cu, Ni, Pb and Zn in soil-rice system was significantly higher than that of vegetables and maize. Soil pH, CaO, organic matter, Fe2O3, K2O and MgO had significant negative correlation with heavy metal bioaccumulation coefficient, but there was a significant positive correlation between bioaccumulation factor of K2O, MgO and Hg in soil-leaf vegetable system.