桉树人工林与杉木林、毛竹林土壤理化性质对比研究

在对永安市尾巨桉人工林、杉木林、毛竹林野外调查取样和室内实验分析基础上，对11年生尾巨桉林、3年生尾巨桉林与杉木林和毛竹林的土壤理化性质进行全面比较．结果表明，3年生尾巨桉林各层土壤中的土壤有机质、全氮和碱解氮、全磷和速效磷、全钾和速效钾含量大多低于其他3种林地，反映了处于速生期的桉树对养分的旺盛需求和消耗；并且，速生期桉树还会造成一定程度的土壤表层粘粒下移和酸化；但随着桉树种植年限的增加，这种状况有所改善．在此基础上，提出变炼山全垦为块状整地，速生期人工施肥，延长轮伐期，实行间种、轮栽并适当休闲养地，提高桉树人工林生物多样性等措施，以实现桉树人工林土壤养分平衡与生态系统的良性循环．

A Comparative Study on Physical and Chemical Properties of Soils in Eucalyptus Plantations,Chinese Fir Plantations and Bamboo Forest

By field and lab work, the differences of soil properties in a 3-year-old and an 11- year-old Eucalyptus grandis plantations, Chinese fir plantations and bamboo forest, all of which located in Yongran city of Fujian province, were examined. It was found that contents of soil organic matter, total nitrogen and available nitrogen, total phosphorus and available phosphorus, potassium and available potassium in the 3-year old Eucalyptus grandis plantation were almost the lowest, indicating that during the fast-growing period, great amount of soil nutrients had been consumed by Eucalyptus trees. In addition, the moving down of surface clay and soil acidification, to some degree, could be observed in the plantation. The study also showed that, as the Eucalyptus trees continue to grow, such soil degradation in the plantation would be slightly improved under natural condition. However, to combat the deterioration of soil conditions and improve nutrients balance in Eucalyptus plantations, artificial interference would be needed. So a series of countermeasures were put forward in conclusion part of the present article, among which, shifting from so called whole-and-burning reclamation to plot-by-plot reclamation, fertilizing in fast-growing stage, extending wood-cutting rotation period, practicing inter-species or inter-planting, allowing related lands to lie fallow appropriately and improving biodiversity in Eucalyptus plantations, were stressed.