贵州烟区紫色土养分状况的综合评价

Comprehensive Evaluation on Purple Soil Fertility of Tobacco Planting Areas in Guizhou

对贵州烟区紫色土的养分状况进行了综合评价。将55个紫色土样品的10项养分指标进行主成分分析，按承积贡献率达到85％以上提取6个主成分，求出各土样的主成分得分，并对综合得分进行聚类分析，把供试土样分为高（Ⅰ）、较高（Ⅱ）、中等（Ⅲ）和较低（Ⅳ）4个等级，各等级所占比例分别为12．7％、29．1％、36．4％和21．8％。第Ⅰ等级的综合得分≥0．5323，各养分含量最高；第Ⅱ等级的综合得分为0．0631～0．3845，除有机质和CEC含量显著低于第Ⅰ等级外，其它养分含量与第Ⅰ等级差异不显著；第Ⅲ等级的综合得分为-0．2349-0．0056，除速效磷含量显著低于第Ⅱ等级外，各养分含量中等；第Ⅳ等级的综合分≤-．3003，总体上养分含量较低。

Ten nutrient indexes of 55 purple soil samples were used to analyze the principal components. Six principal components were picked up according to over 85% of the contribution rate to calculate the scores of principal components of each soil sample, and then the scores were analyzed by the cluster method. The tested soil samples could he divided into 4 grades including higher （Ⅰ ）, high （Ⅱ）, medium （Ⅲ） and low （Ⅳ）, which took up 12.7%, 29. 1%, 36.4% and 21.8% of the total soil samples respectively. The total score of grade Ⅰ with the highest contents of soil nutrients was ≥ 0. 5323. The total score of grade Ⅱ without the significant difference from that of grade Ⅰ except contents of organic matter and CEC was 0. 0631 -0. 3845. The total score of grade Ⅲ with medium contents of soil nutrients except available P being significantly lower than that of grade Ⅱ was -0. 2349-0. 0056. The total score of grade Ⅳ with the lowest contents of soil nutrients was≤ -0. 3003.