南丹矿区周边农田土壤质量综合评价研究

Comprehensive evaluation study on soil quality of agricultural land around Nandan mining areas

目前的土壤质量综合评价存在评价灵敏度高度依赖样本选取、评价结果不够全面、肥力指标选取比较主观等问题,应用受到限制.因此,本研究在现有土壤质量综合评价方法基础上,引入动态加权评估法,对土壤质量指数法进行改进,提出改进土壤质量指数法(I-SQI).通过实例进行I-SQI与改进的内梅罗综合指数法(I-NPI)和逼近理想解排序法(TOPSIS)的对比分析,发现I-SQI对不同状况的土壤都表现出较好的适用性,评价结果全面且灵敏性高,有效地解决了目前方法存在的问题.应用该方法对广西南丹矿区周边农田土壤进行综合评价,结果发现:(1)研究区土壤肥力处于中等及以下水平,可交换钙、粘粒、电导率、总氮、速效钾、容重这6个指标是影响研究区农田土壤肥力的关键指标;(2)研究区大部分农田存在重金属污染,As、Cd、Pb和Zn4种重金属元素是影响矿区土壤环境质量的主要污染因子;(3)研究区农田土壤质量以不及格和及格为主,亟需得到改善.本研究为土壤质量综合评价的发展提供了新的阶梯.

The current comprehensive soil quality evaluation is highly dependent on sample selection for evaluation sensitivity,the evaluation results are not comprehensive enough,and the selection of fertility index is rather subjective,leading to limited applications.Therefore,the improved soil quality index method(I-SQI)was proposed by introducing the dynamic weighted assessment method based on the existing comprehensive soil quality evaluation method.The comparative analysis of I-SQI with the improved Nemerow pollution index method(I-NPI)and technique for order preference by similarity to an ideal solution(TOPSIS)of the current method was carried out by example,and it was found that I-SQI could show better applicability to soils with different conditions,and the evaluation results were comprehensive and sensitive,which effectively solved the problems of the current method.Applying this method to the comprehensive evaluation of farmland soils around Nandan mine in Guangxi,it was found that①soil fertility in the study area was at an intermediate level or below,and the six indicators of exchangeable calcium,clay particles,conductivity,total nitrogen,available potassium,and bulk density were the key indicators affecting the fertility of farmland soils in the study area;②most of the farmland in the study area had heavy metal pollution,As,Cd,Pb and Zn were the main pollution factors affecting the soil environmental quality in the mining area;③the soil quality of farmland in the study area was mainly failing and passing,which needed to be improved urgently.This study provides a new stepping stone for the development of comprehensive soil quality evaluation.