川西亚高山针叶林人工恢复过程的土壤性性质变化

研究川西岷江上游高山针叶林区不同年龄阶段的人工云杉林地凋落物及其养分贮量和土壤养分及主要理化性质的变化趋势，结果表明：（1）人工云杉林的凋落物及其氮、磷、钾贮量、以60年代抚育成熟林最高，40年代抚育成熟林大幅度下降，分别下降34．1％及49．8％，70．5％，46．7％；（2）人工云杉林地表土的有机质、全氮、全磷随林龄的增加而降低，据典型土壤剖面资料，40年代比60年代抚育林土壤分别降低72．4％，78．6％，42．2％；（3）相应于土壤有机质的变化，与60年代人工云杉成熟林相比，40年代成熟林土壤的自然含水量、总孔工、保肥力（CEC）和交换性盐某养分等均明显降低，表现出肥力退化的趋势，因此，当人工云杉林达到成熟林后，后采取诸如适当间伐等措施，以改善林地生态条件，避免土壤肥力退化，图4表6参11。

Changes of soil properties during artificial recovery of subalpine coniferous forests in western Sichuan

The change trends of the litter and its storage ,soil nutrient and its main physical chemical properties at different age stages of artificial spruce at subalpine were studied in the area to Min river upstream in the west of Sichuan. The results indicated that: (1) The storage quantity of litter , N, P 20 5 and K 20 of 1960's artificial spruce forest was the highest, but those 1940's artificial spruce forest declined greatly, with 34.1 %, 49.8% 70.5% and 46.7% respectively; (2) The contents of soil surface organic matter, N, P 20 5 and K 20 deceased with the increase of stand age. By typical soil profile survey, the content of soil surface organic matter, N and P 20 5 of 1940's artificial spruce forest declined 72.4%,78.6% and 42.2% respectively than those of 1960's; (3)Compared with those of 1960's, soil natural water content , total porosity, CEC, exchangeable bases and so on of 1940's artificial spruce mature forest decreased distinctly, and soil fertility degraded greatly. Therefore, in order to avoid soil fertility degradation and improve the stand ecology environment, the rational inter cut down and measure management of such as fostering ought to be adopted after artificial spruce forest matured. Fig 4, Tab 6, Ref 11