不同栽杉代数根际土壤肥力及生物学特性变化

通过对位于南平溪后安曹下和邓窠２９ａ龄１代、２代、３代实生杉木的根际养分、微生物、酶及生化活性的为期２ａ的研究，结果表明：随杉木连栽代数增加，根际微域土壤酸化趋势增强，有机质和全氮沉积量下降，速效性养分亏缺程度减弱，根际土壤中三大类微生物所占的比例发生一定的变化，真菌和放线菌所占比例增加，细菌所占比例减少，生理类群数量下降，除接触酶活性变化不大外，其它土壤酶和生化活性均有明显下降，体现了杉木多代连栽根际土壤的基本特征；亦是杉木连栽导致地力衰退重要原因之一

VARIATION OF RHIZOSPHERIC SOIL FERTILITY UNDER DIFFERENT CHINESE FIR ROTATIONS

A 2a study on nutrients, microbes, enzyme and biochemical activities of rhizospheric soil under 29 year old Chinese fir stand of generations 1,2 and 3 growing in Ancaoxia and Denke, Xihou, Nanping indicated that with the increasing generations of Chinese fir, the pH value of rhizospheric soil went down and the soil acidification increased. The contents of soil organic matters and total nitrogen decreased, the depletion of soil available nutrients decreased, the proportion of bacteria, fungi and actinomyces changed to a certain extent, the proportion of fungi and actinomyces increased, but the proportion of bacteria decreased, the soil physiological groups, soil enzyme and biochemical activities declined obviously except catalase. All above reflected the main characteristics of rhizospheric soil under continuous plantation of Chinese fir. It may be one of the important factors causing the soil fertility decreased under Chinese fir plantantion.