Assessment of Soil Fertility in Eucalyptus Plantation in Guangxi by Principal Component Analysis and Fuzzy Mathematics

From November to December 2017, 270 soil samples were collected under Eucalyptus plantation from eight forest farms, Guangxi Zhuang Autonomous Region. Soil pH and 14 soil fertility indicators were determined and comprehensive evaluation of the soil fertility for Eucalyptus plantation was carried out by the methods of principal component analysis and fuzzy mathematics. The results showed that Eucalyptus plantation soil showed acid, rich in exchangeable Ca content. Contents of soil organic matter, total N, total K, alkali-hydrolyzable N, exchangeable Mg, available Cu, available B and available Zn were at medium level, while that of soil total P, available P, available K and available Fe contents were insufficient. Contents of soil organic matter, alkali-hydrolyzable N, available P, available K, available Fe and available B contents were the main factors affecting the soil fertility. According to integrated fertility index, the soil fertility of Eucalyptus plantation from eight forest farms was 0.160-0.678, dominated by grade IV, followed by grade III and V.