天水苹果园土壤重金属富集状况评价及来源分析

对天水果园表层（0~20 cm）219件土壤样品进行研究,测定5种重金属（Zn、Cu、Pb、Cr和Cd）及有机质含量,以天水小陇山土壤为对照,运用相关分析和主成分分析方法区分土壤中重金属的来源。结果表明,①Zn、Cu、Pb、Cr和Cd含量分别为77.39、23.03、23.62、61.49 mg.kg-1和0.07 mg.kg-1,其中Cd极显著（P〈0.01）高于小陇山土壤,其余4种重金属虽高于小陇山土壤但无显著差异性（P〉0.05）;②研究区土壤Cu、Pb、Cr三者间在0.01或0.001水平上具有显著正相关性,且这3种重金属与土壤有机质具有显著正相关性,其余重金属间不存在显著相关性;③主成分分析显示Cu、Pb和Cr来源相似,主要来自于成土母质,Cd来源于人为施肥因素,Zn的富集受多种因素影响。研究评价结果显示,天水地区果园土壤Cd受人为施肥影响较大,具有一定程度的富集。

Source and Enrichment Situation of Heavy Metals in Apple Orchard Soils of Tianshui Area,China

Concentrations of Zn,Cu,Pb,Cr,Cd and organic matter were investigated in apple orchard topsoils（0~20 cm）in Tianshui area.Correlation analysis and principal component analysis were taken to identify the sources of these heavy metals in soils compared with soils of Xiaolong mountain from Tianshui area.The results suggested that：①the contents of Zn,Cu,Pb,Cr,Cd in apple orchard soils were 77.39,23.03,23.62,61.49,0.07 mg·kg-1 respectively,and the Cd content was significantly（P0.01） higher than Xiaolong mountain soil;②There were significantly correlation among Cu,Pb,Cr and organic matter in apple orchard soils;③Cu,Pb and Cr in soils were mainly related to the geology of the parent material of the soils.Cd in the apple orchards soil originated from agricultural fertilizer according principal component analysis.Enrichment of Zn in the soils was affected by other factors.Agricultural action was the major reason of Cd content in the orchard soils which was higher than other metals.