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研究川西岷江上游亚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 6 0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 6 0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 6 0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、总孔隙度、保肥力 (CEC)和交换性盐基养分等均明显降低 ,表现出肥力退化的趋势 .因此 ,当人工云杉林达到成熟林后 ,应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
The results showed that: (1) The litter of Artificial spruce-fir stand and its nutrient storage, soil nutrients and its main physical and chemical properties at different ages in the sub-alpine coniferous forest in the upper reaches of the Minjiang River in western Sichuan were studied. The results showed that: The nitrogen, phosphorus and potassium reserves were the highest in the mature forests in the 1960s and the mature forests in the 40s declined significantly by 34.1% and 49.8%, 70.5% and 46.7% respectively. (2) Soil organic matter, total nitrogen and total phosphorus of artificial spruce forest surface soil decreased with the increase of forest age. According to the data of typical soil profiles, the soil in the 40 years was 72.4%, 78.6%, 42.2% ; (3) Corresponding to the changes of soil organic matter, the natural water content, total porosity, fertility conservation (CEC) and exchangeable basal nutrient of mature soil in 40 years were significantly higher than those in artificial spruce mature forest in 60 years Therefore, when the artificial spruce forest reaches the mature forest, measures such as appropriate thinning should be taken to improve the ecological conditions of the forest land and avoid the degradation of soil fertility.