基于粗糙集属性约简法的植烟土壤肥力评价分析

Analysis on evaluations of fertility of tobacco-growing soil based on attribute reduction in rough set

为建立更合理的植烟土壤评价方法,以江苏中烟某原料基地的植烟土壤为研究对象,采用层次分析法和基于粗糙集的属性约简法对土壤肥力的综合状况进行评价,并利用当年的烟叶产量对评价结果进行检验。结果表明:①15个采样点土壤肥力指标间的差异不同,其中有机质、碱解氮、水溶性氯、速效磷、速效钾、有效硫和有效镁含量(质量分数)7项指标差异较大,全钾、有效硼、有效钼、有效钙含量(质量分数)和土壤pH 5项指标差异较小,采样点的全氮和全磷含量(质量分数)指标差异不显著。②经多重比较筛选并利用层次分析法确定有机质、碱解氮、速效磷、速效钾、有效镁和水溶性氯含量的初始权重分别为0.229、0.357、0.120、0.189、0.055、0.050。③基于粗糙集的属性约简法确定的最小近似约简为有机质、速效磷、速效钾和水溶性氯含量指标,权重系数分别为0.214、0.214、0.321和0.251。④利用层次分析法和基于粗糙集的属性约简法得到的土壤综合肥力评价结果不尽相同,不同方法计算得到的土壤综合肥力指数与当年的烟叶产量均呈显著线性相关,相关系数(r)值分别为0.65和0.92,决定系数(R^(2))分别为0.42和0.86,均方根误差(RMSE)分别为5.92和5.89,基于粗糙集属性约简法的相关性更好,精度更高。

In order to develop a more reliable evaluation method for tobacco-growing soil,soil samples were collected from a raw material site of China Tobacco Jiangsu Industrial Limited Corporation and the comprehensive state of the soil sample fertility was evaluated by analytic hierarchy process(AHP)and attribute reduction method in rough set.The evaluation results were verified by the tobacco leaf yield of the corresponding year.The results showed that:1)The differences of soil fertility indices from 15sampling sites were not the same.There were significant differences in 7 indices,such as the contents(mass fraction)of organic matter,alkali-hydrolyzed nitrogen,water-soluble chlorine,readily-available phosphorus,readily-available potassium,available sulfur and available magnesium.There were smaller differences in soil pH and contents of total potassium,available boron,available molybdenum and available calcium,while there were no significant differences in total nitrogen and total phosphorus.2)All the indices screened by multiple comparisons and their initial weight coefficients determined by the AHP were contents of organic matter(0.229),alkali hydrolyzed nitrogen(0.357),readily-available phosphorus(0.120),readily-available potassium(0.189),available magnesium(0.055)and water-soluble chlorine(0.050).3)The minimum approximate reductions determined by the attribute reduction method in rough set were contents of organic matter,readily-available phosphorus,readily-available potassium and water-soluble chlorine,and their weight coefficients were 0.214,0.214,0.321 and 0.251 respectively.4)The evaluation results of comprehensive state of soil fertility obtained through the AHP and the attribute reduction method in rough set were different.The comprehensive soil fertility results obtained by different methods were significantly linearly correlated with tobacco leaf yields,the correlation coefficients(r)were 0.65 and 0.92,determination coefficients(R^(2))were 0.42 and0.86,and root mean square error(RMSE)were 5.92 and 5.89,respectively.The attribute reduction method in rough set had higher correlation coefficients and accuracy.