基于土壤肥力和重金属污染风险的农用地土壤质量综合评价研究

对博兴县土壤质量综合评价，为当地土壤资源的科学管理和可持续利用提供重要依据。本研究以土壤pH、有机质、有效磷、速效钾、碱解氮和土壤重金属Cr、Pb、Cd、As、Hg含量数据为基础，采用指数和法对土壤肥力、内梅罗指数法对土壤重金属污染风险进行评价，再引入逼近理想解排序法（TOPSIS）对土壤质量综合评价。结果表明:研究区农用地土壤有机质平均含量为17.85 g kg?1，较为缺乏；土壤有效磷、速效钾、碱解氮的平均含量为36.89、192.46、98.47 mg kg?1，较为丰富；土壤综合肥力指数平均值为0.63，土壤肥力总体表现为中上等水平，在空间上呈现由南到北，由东到西逐渐降低的趋势；Cd的单因子指数P_i (1.03) > 1，表明部分地区土壤存在Cd的轻度污染，其他4种重金属虽有不同程度的积累，但均未超过土壤环境质量标准；博兴县农用地共分为优质区、良好区、中等区、一般区、较差区5种类型，分别占农用地总面积的23.53%、33.01%、15.82%、18.75%、8.89%。总体上看，博兴县大部分农用地无明显的重金属污染，且土壤肥力水平较高，土壤综合质量处于良好及以上水平。

Comprehensive Evaluation of Soil Quality of Agricultural Land Based on Soil Fertility and Heavy Metal Pollution Risk: A Case Study of Boxing County,Shandong Province

Comprehensive evaluation of soil quality was conducted to provide an important basis for the scientific management and sustainable use of soil resources in Boxing County in this study. Soil nutrient indices (SOM, AP, AK, AN and pH) and five toxic heavy metals (Cr, Pb, Cd, As and Hg) were evaluated by using the index method and Nemerow comprehensive index method, respectively. At last, the TOPSIS method was applied to evaluate soil quality comprehensively. The results showed that the mean value of the organic matter content area was 17.85 g kg?1, which was at a lower level. Soil AP was 36.89 mg kg?1, which was at a higher level. The average value of soil fertility index was 0.63, suggesting overall soil fertility level was at a middle-high level. It showed a trend of gradual decline from south to north and from east to west in spatial distribution. The single factor index of Cd was greater than 1, which indicated soil was at light pollution. The other four heavy metals accumulated in varying degrees while still within the safe ranges of the environmental quality standard for soils. The agricultural land area in Boxing was divided into five types: high-quality area (25.33%), good-quality area (33.01%), medium-quality area (15.82%), general-quality area (18.75%), and poor–quality area (8.89%). On the whole, there was no obvious heavy metal pollution in the soil in Boxing County. The soil fertility level was relatively high and soil comprehensive quality in most areas was at a high-quality level.