Changes of soil nutrients and enzymes activity on Chinese-fir-clear-cutting land and their utilization

Effects of soil on growth and fruiting of trees and biochemical characteristics of the soil were studied by planting non-timber species on both Chinese-fir-clear-cutting land and non-Chinese-fir-clear-cutting land .Its shown that organic matter , total nitrogen , hydrolysable nitrogen , available phosphate and contents of urease , proteinase , hydrogen peroxidase , etc .decreased to different extents , thus soil fortility declining .As a result , early growth of trees was suppressed to some extent , which was particularly obvious in such fast growing species as Vatica astrotricha and Phyllostachys pubescens .When Chinese-fir-clear-cutting land was reutilized , measures such as deep scarification and improvement of soil and application of basal manure were taken , with early fruiting , high yield and good quality obtained inVatica astrotricha ,Castanea mollissima , Ginkgo biloba , etc .Thus the sustainable utilization of Chinese-fir-clear-cutting land could be realized .