云南省植烟区土壤养分差异性分析与肥力综合评价OA

The representative tobacco fields covering 88 tobacco-growing counties(districts)of 12 prefecture-level cities were selected as research objects.A total of 564 topsoil samples were collected,and nine soil nutrient indicators were determined,including pH,soil organic matter,alkali-hydrolysable nitrogen,water-soluble chlorine,total nitrogen,available phosphorus,available potassium,total phosphorus and total potassium.Multiple comparisons were performed to analyze the differences in each soil nutrient indicator among tobacco-growing regions.Hierarchical cluster analysis was adopted to clarify the spatial differentiation grouping characteristics of soil nutrients in different prefecture-level cities.Furthermore,fuzzy mathematics membership functions combined with principal component analysis(PCA)were used to quantify the integrated fertility index(IFI)of soil.The results showed that:(1)Significant regional variations existed in soil nutrients of tobacco-growing areas in Yunnan,with coefficients of variation(CV)of the nine indicators ranging from 12.17%to 81.92%.Total phosphorus,available phosphorus and water-soluble chlorine exhibited extremely uneven spatial distributions.The pH value,organic matter,total nitrogen,available phosphorus and available potassium fell within the optimal ranges.Alkali-hydrolysable nitrogen was generally excessive,while total phosphorus,total potassium and water-soluble chlorine were insufficient in most regions.(2)Cluster analysis showed that the spatial distribution of soil nutrients failed to follow geographical adjacency,indicating that micro-environmental conditions and anthropogenic management exerted stronger impacts on soil properties than geographical proximity.(3)Soils with medium-high and medium fertility dominated all tobacco-growing areas,accounting for 53.72%and 36.17%of the total samples,respectively.High-fertility and low-medium-fertility soils accounted for 5.32%and 4.79%,respectively.Chuxiong and Lijiang presented relatively low integrated soil fertility.In conclusion,it is recommended to increase the application of phosphorus and potassium fertilizers and strictly control nitrogen input in low-fertility zones,while maintaining the current fertilization regimes in high-fertility zones,so as to support the green and high-quality development of the flue-cured tobacco industry.