基于突变理论的土地质量地球化学评价方法研究

Land Quality Geochemical Evaluation Based on Catastrophe Theory

为实现土壤肥力和土壤环境质量相结合的土地质量地球化学综合评价结果的高精度量化,依据赣南南康地区采集的6266组表层土壤样品测试结果,构建了以As、Hg、Cd、Pb、Cr含量等为基础的内梅罗指数和以有机质(SOM)、P、N、K、Mo、Mn、B、Cu、Zn含量等为基础的土壤综合肥力指数为控制因素的突变理论法土地质量地球化学综合评价方法,将内梅罗指数3.0修订为3.1,通过突变理论对数据进行标准化和归一化分析,比较原始内梅罗指数和修订内梅罗指数评价结果以及本文方法与DZ/T 0295—2016《土地质量地球化学评价规范》方法的土地质量地球化学综合等级划分结果。结果表明:研究区土壤综合肥力指数均值为0.75,总体综合肥力为Ⅲ等,土壤肥力较低;土壤综合内梅罗指数均值为0.59,总体尚清洁。采用修订后的内梅罗指数3.1计算的土壤肥力指数分界值基本呈等级等间距划分。与DZ/T 0295—2016《土地质量地球化学评价规范》评价结果比较,83.57%的结果等级未发生变化,近16%等级结果增加1个等级,主要为1级和2级升为3级和4级,未出现2个及以上等级的变化,评价结果显示3级、4级面积占比为94.11%、5.30%。本文方法可用于土地质量地球化学综合等级评价,评价结果更加数值化、精细化,评价过程更简便,是对已有土地质量地球化学综合评价方法的补充,可为土地利用、农业生产和管理提供借鉴和参考。

According to the test results of 6266 groups surface soil samples collected in Nankang area of southern Jiangxi,to achieve high-precision quantification of land quality geochemical evaluation coupling soil fertility and soil environmental quality,a cusp catastrophe model was established and applied to evaluate land quality geochemical evaluation.In this model,soil fertility index(P_f),including SOM,P,N,K,Mo,Mn,B,Cu,Zn in solid samples was the main variable,Nemerow index(P_n),including As,Hg,Cd,Pb,Cr in solid samples was the secondary variable,for values greater than 3 of P_f,P_f were revised to 3.1,and the influences of adjusting on the results were compared.The results showed that the average of P_f was 0.75 and the overall level of soil fertility wasⅢ,the soil fertility was lower,the average of P_n was 0.59 and the overall level of soil contamination was cleaner.The linear relationship between the boundary value of soil fertility index calculated by the adjusting Nemerow index and the land quality grade was better.The results of comparing with DZ/T 0295—2016 showed that 83.57%of the evaluation grades were the same,and nearly 16%of the grade was increased by one grade,the range of grade increase or decrease did not exceed 1.The area of grade 2 was mainly distributed in the southeastern edge and the middle-northern part of the study area,the area of grade 3 was widely distributed,and the area of grade 4 was sporadically distributed.The research results showed that the method can be used for the comprehensive evaluation of land quality geochemistry,with more numerical and simpler evaluation process,it was a supplement to existing methods for comprehensive evaluation of land quality geochemistry which can provide effective reference.