苏南经济快速发展区土壤Ni的形态分布影响因素——以昆山市为例

Factors Influencing Chemical Forms of Soil Ni in the Rapidly Developing Region of South Jiangsu Province——A Case Study from Kunshan City

以江苏省昆山市为典型区,通过现场采样及室内分析测定,定量研究了几种因素对农田土壤Ni形态分布的影响。结果表明:(1)土壤有效态Ni含量为1.31 mg.kg-1,土壤全Ni含量为40.95 mg.kg-1,土壤Ni的活化率为3.38%。(2)土壤重金属Ni各形态含量相对大小为残渣态(36.20 mg.kg-1)>有机质结合态(2.80 mg.kg-1)>铁锰氧化物结合态(1.31 mg.kg-1)>可交换态(0.54 mg.kg-1)、碳酸盐结合态(0.10 mg.kg-1),残渣态含量明显高于其他形态,达88.16%。(3)pH值是影响可交换态Ni含量的最主要因素,达极显著负相关水平;全Ni含量是影响碳酸盐结合态Ni含量、铁锰氧化物结合态Ni含量和残渣态Ni含量的最主要因素,达极显著正相关水平;有机质含量是影响有机质结合态Ni含量的最主要因素,呈显著正相关水平。(4)<0.01 mm粘粒含量是影响可交换态Ni含量的重要因素,有机质含量是碳酸盐结合态Ni含量的重要影响因素,pH值和有机质含量都是影响铁锰氧化物结合态Ni含量的重要因素,<0.01 mm粘粒含量、pH值都是影响有机质结合态Ni含量的重要因素,pH值是影响残渣态Ni含量的重要因素。

Taking Kunshan city of Jiangsu Province as study area,the chemical forms of Ni in the agricultural soils were identified and the factors influencing content distribution of soil Ni forms were studied.The results showed that,average content of available Ni in the studied soils was 1.31 mg.kg-1,while average content of total Ni 40.95 mg.kg-1,indicative of an available rate of 3.38%.The different forms of Ni fol-lowed in order of their contents in soil：residue Nithat bound to organic matter bound to iron and manganese oxides exchangeable and bound to carbonates.Amongst all sorts of the detected Ni forms,content of the residue Ni had a dominant percentage（88.16%）of the total Ni in studied soils.It was found that pH value had extremely significant negative correlation with the content of soil exchangeable Ni,demon-strating its important influence on this Ni form,while the contents of Ni bound to carbonates,bound to oxides,and residue Ni were all posi-tively tied to that of total soil Ni.As expected,a higher SOM content commonly leaded to a higher content of Ni bound to SOM.Besides pH value,soil clay（ 0.01 mm）content also was one of important factors influencing the content of soil exchangeable Ni.And,SOM content not only had the dominant influence on content of Ni bound to SOM,but also exert an influence on Ni bound to carbonates and to Fe-Mn oxides.Besides exchangeable Ni,contents of Ni bound to SOM,to Fe-Mn oxides and soil residue Ni were affected by pH value to different degree.