杉木人工林的土壤性质变化

系统研究和分析了不同代、不同发育阶段杉木林的土壤物理性质、化学性质和生物特性的变化过程,揭示了杉木人工林随着栽植代数增加(2～3代),土壤物理性质变劣,pH值下降,养分含量降低,速效P和水解N的下降尤为明显,微生物区系及酶活性也朝着生物活性下降的方向变化,也反映出杉木人工林不同发育阶段土壤肥力的差别。一般从幼龄林到中龄林土壤肥力呈下降趋势,到了成熟林阶段土壤肥力稍有上升,但不能恢复到原来的状态。在现行栽培制度下,杉木人工林连作能导致土壤功能衰退,这是杉木人工林不能保持长期生产力的主要原因之一。

Variation of Soil Properties of Chinese Fir plantation

The variations of physical,chemical properties and biological characteristics of soil in Chinese fir Cunninghamia lanceolata plantation with different cultural rotations (from one to three) and development stages are studied and analyzed.It is showed that with the increase of rotation,the soik physical properties deteriorate,the pH value decreases and the nutrient content becomes poorer,especially the contents of available P and hydrolytic N.The microorganism quantity and soil enzyme activity change to toward the declination of biological activity.In different development stages,the soil fertility differs.In the stage from young plantation to middle aged plantation,the soil fertiliity decrease while it will increase in the mature stage.But the soil fertility can not be recovered thoroughly.Under present culture system,the successive culture of C.lanceolata plantation will result in the declination of soil complex function,which is an important reason why C.lanceolata plantation can not keep high productivity for a long term.