山东省泰安市28个桑园的土壤肥力数值化综合评价

Comprehensive Evaluation of Soil Nutrient Scalarization of 28 Mulberry Fields in Taian City of Shandong Province

为了准确评估不同桑园的土壤肥力状况,采用比色法、原子吸收法等化学分析方法测定山东省泰安市岱岳区28个桑园的土壤养分含量,利用模糊数学方法中的综合指数评价模型,结合因子分析、主成分分析、聚类分析等方法,对28个桑园土壤的15项土壤肥力属性进行分析之后,对各桑园的土壤肥力状况进行综合评价和分级。调查的28个桑园的土壤pH适宜,大部分桑园土壤有机质和氮、镁、锌元素含量偏低,个别桑园缺乏其它营养元素。桑园土壤肥力综合评价的最小数据库集(MDS)包含全氮、pH值、碱解氮、有效铁、速效磷、速效钾、有机质和全磷8项指标,指标权重为各自公因子方差的百分比,据此测算28个桑园的土壤综合肥力指数平均值为0.25,变幅为0.18～0.34,可划分为高、较高、中等和偏低4个肥力等级,各等级桑园的比率分别为21.4%、25.0%、39.3%及14.3%。采用上述数值化综合评价与分析方法,可提高土壤肥力评价的定量化水平和科学性,减少评价过程中主观因素的影响。今后应根据桑树生长需求规范桑园土壤肥力丰缺标准及隶属度函数阈值,形成更加全面、客观、科学的评价标准。

In order to accurately evaluate soil fertility status of different mulberry fields, soil nutrient contents of 28 mul berry fields in Daiyue District of Taian City, Shandong Province, were determined by chemical analysis methods including colorimetry and atomic absorption spectrometry, and 15 indexes of soil fertility property of the 28 mulberry fields were an alyzed by factor analysis, principal component analysis and cluster analysis by employing the model of comprehensive index evaluation in fuzzy mathematics. Based on these analyses, the soil fertility status of different mulberry fields was comprehensively assessed and graded. The results demonstrated that pH values of soil in 28 surveyed mulberry fields were suitable, and the contents of organic matter, nitrogen, phosphorus and potassium elements were low in mostmulberry fields, while lack of other nutrient elements was found in a few mulberry fields. The minimum data set （MDS） contained 8 indexes, namely total nitrogen, pH value, alkalized nitrogen, available iron, available phos phorus, available potassium, organic matter and total phosphorus. The index weight was percentage of vari ance of each common factor. It was thus calculated that the average integrated soil fertility index of 28 surveyedmulberry fields was O. 25 with a variation range of O. 18 to O. 34. The soil fertility was divided into four grades, namely the highest, higher, medium and low levels, and mulberry field of each grade accounted for 21.4%, 25.0%, 39.3% and 14.3%, respectively. With the help of above comprehensive scalarization and analyses, comprehensive evaluation of soil fertility could be improved both quantitatively and scientifically, and the influence of subjective factors could be re duced in the evaluation process. In the future, the abundance and deficiency standards and the threshold values of membership function should be standardized according to the demand of mulberry growth, so as to form a more com prehensive, objective and scientific evaluation criterion.