人工苹果园持续时间对土壤重金属分布的影响

以陕西渭北旱塬典型苹果园为研究对象,运用SPSS数理统计软件进行数据分析,对该区洛川县不同种植年限苹果园土壤重金属含量进行研究,试图阐明种植年限对果园土壤发育过程的影响。结果表明:该区苹果园的高投入种植管理模式,能够影响重金属在土壤中的迁移与富集,使土壤重金属含量发生明显变化。随着树龄的增加(0→60 a),在0~20,20~40、40~60 cm各土层砷含量的差异逐渐减小(4.1→0.4 mg/kg);40 a树龄果园土壤铬含量在各个土层均达最高值(分别为:87.3、89.7和94.6 mg/kg),而60 a果园则在各个土层均达最低值(分别为:76.0、79.5和73.3 mg/kg);0~20 cm,铜含量与镍含量随树龄增加呈线性递增趋势(22.9→31.7 mg/kg与29.6→31.9 mg/kg);不同种植年限果园土壤铅含量均随土层深度的增加而降低;不同种植年限果园土壤锌含量随土层深度的变化没有明显的变化规律。不同树龄果园土壤环境指标的综合污染指数均小于0.7,土壤环境质量为清洁。

Effects of artificial apple orchard planting ages on soil heavy metals distribution

The paper studied the effect of different planting ages of apple orchards on distribution of soil heavy metal in order to lay the theoretical foundation for the hiigh quality of apple production in the Weibei Highland.Numerous studies focused on the spatial distribution of soil heavy metal of specific aged vegetable greenhouse.However,few studies were done for different artificial planting ages of apple orchards.In this paper,the principle and methods of geo-statistics(SPSS)were used to investigate the content of soil heavy metal at three soil depths(0-20 cm,20-40 cm,and 40-60 cm)of different aged apple trees(0,20,40,and 60 years)at the arid Weibei Highland in the Loess Plateau,Luoehuan County,Shaanxi Province,China.The results showed that high input and different apple tree ages have an obviously effect on soil heavy metal content and its migration.Soil As content change pres- ents reducing tendency(4.1→0.4 mg/kg)on the different soil layers along with the tree age increases(O→60years).Soil Cr content is higher in 40-year apple orchard at the different soil layers(87.3,89.7 and 94.6 mg/kg,respectively),but is lower in 60-year apple orchard at the different soil layers(76.0,79.5 and 73.3 mg/kg,re-spectively).As to 0-20 cm,the soil Cu and Ni contents increase progressively along with the tree age growing in a line(22.9→31.7 mg/kg and 29.6→31.9 mg/kg).Soil Pb content of apple orchards ofdifferent planting ages all reduces along with the soil layer increases.The change of soil Zn content of apple orchard of different planting ages has no obvious rule in different soil layer.But the synthetic pollution indices of soil heavy metals of all soil samples were below 1,the soil environment quality of artificial orchard of 0,20,40 and 60 years in Luochuan was good,reaching the"clean"level.The apple orchards of Luochuan are in accordance with the demand of the pollution-free apple production by the national environment quality standard for soils.