湖南桂阳烟区土壤养分状况的综合评价

对湖南省桂阳县烟区的345个土壤样品、9项土壤养分指标进行了测定,确定了各指标所属的隶属函数类型及其阈值,采用偏相关分析法求得各指标的权重,运用加乘法算出各土样的土壤肥力综合指标值(IFI),进而对桂阳县植烟土壤适宜性进行了综合评价。结果表明:桂阳烟区土壤肥力存在广泛的变异,其IFI值平均为0.495,变幅为0.223~0.804,变异系数22.5%。采用聚类分析方法将土壤肥力分为高、较高、中等和较低4类,各类土样所占比例依次为16.16%、27.08%、32.16%和24.60%。该区土壤pH值、有机质、全氮和碱解氮含量偏高,全磷含量较低,全钾和有效钾含量供应不足,建议该区平衡施肥应注意控氮、补磷、增钾。

Comprehensive evaluation of the status of soil fertility in Guiyang tobacco-growing areas of Hunan province

9 indexes of the soil nutrient contents including organic matter,total N,total P,total K,hydrolytic N,available P,available K,pH value and water soluble Cl of 345 soil samples from Guiyang tobacco-growing areas in Hunan Province were analyzed.Types of membership function and threshold values for each fertility index were determined.The method of partial correlation analysis was employed to calculate the weight of each fertility item;the additive and multiplicative theorem was used to estimate integrated fertility index(IFI) of each soil sample.The results of comprehensive evaluation indicated that there existed significant variation for the soil fertility of Guiyang tobacco-growing area.IFI values of the whole soil samples range from 0.223 to 0.804,with the mean of 0.495 and the coefficient of variation of 22.5 %.The soil fertility could be classified into four gradings of high,higher,medium and low by cluster analysis,which took up 16.16 %,27.08 %,32.16 % and 24.60 % of the total,respectively.The pH value,the contents of organic matter,total N and hydrolytic N were too high in general;the content of total P was lower;the contents of total K and available K were obviously deficient.It was suggested that controlling N,supplying P and increasing K for balanced fertilization in Guiyang tobacco-growing areas.