第二代杉木人工幼林生态系统土壤水文学功能的研究

Hydrological Functions of Soil in the Second Generation Chinese Fir Plantation Ecosystem

以连续 8 a的测定数据 ,探讨了皆伐对生态系统土壤水文学功能的影响 ,并着重研究了营造第二代杉木人工林后林木对土壤水文学功能的生物调节和恢复状况 .结果表明 :皆伐使土壤的蓄水能力下降 2 5 % ,渗透能力下降 2 0 %～ 2 5 % (初渗 )和 10 %～2 4% (稳渗 ) .营造第二代杉木人工林后 ,林地土壤蓄水能力逐步恢复 ,5年生杉木林对土壤蓄水的渗透和调节能力相当于成林的2 7% ,3 8.3 %～ 42 .7% (初渗 )和 3 5 .7%～ 45 .2 % (稳渗 ) .8年生林 ,土壤蓄水能力已接近成林的 93 % ,渗透能力已达到成林的 91.4%～ 94.6% (初渗 )和 90 %～ 98% (稳渗 ) .第二代杉木人工林土壤水分垂直变化与第一代成林相比有很大的不同 .从土壤水分动态变化推断 ,幼林的地下径流量将大于成林 .同时 ,根据影响土壤含水量变化的几个主要因子 ,建立了预测土壤水分动态的数学模型 .

Based on eight years' data, this paper studies the effect of cut over on the hydrological functions of soil in an ecosystem and focuses on the biological regulation and restoration effects of trees on soil hydrological functions after the second generation Chinese fir stand is reforested. The results show that cut over causes the water holding capacity of soil to be reduced by 25%, and the initial and stable permeable capability to be decreased by 20%~25%, 10%~24% respectively. After the reforestation of the second generation Chinese fir stand, the water holding capacity recovers step by step.In five years, the regulation of the yound stand on the soil water holding capacity, the initial and stable permeable capability reaches respectively 27%,38.3%~42.7% and 35.7%~45.2% of that of a mature stand; and in 8 years, the regulation of that stand reaches respectively 93%, 91.4%~94.6% and 90%~98% of that of a mature stand. The vertical change of soil water in the second generation Chinese fir stand is significantly related to the cut over.Based on the dynamic change of soil water, the ground runoff of the yound stand is expected to exceed that of a mature stand. And a model for predicting soil water content is developed according to the main factors that influence the soil water.