秦岭南麓典型林分枯落物和土壤层持水能力评价

    Evaluation of litter and soil water-holding capacity of typical forest stands in southern foot of Qinling Mountains

    • 摘要: 秦岭地区森林水源涵养功能的现有研究集中于区域尺度的模拟评估,缺乏对林分尺度不同森林类型间枯落物和土壤层持水能力差异及影响因素的研究,导致对秦岭水塔功能的机制认识不清。通过野外观测与样地调查,量化比较秦岭生态站内5种优势森林类型枯落物和土壤层持水特性的差异,并采用相关性分析解析影响其持水能力的主要因素。结果表明:秦岭生态站不同森林类型的枯落物和土壤层总持水量为296.74~414.74 t/hm2,其中青杄纯林>油松纯林>锐齿栎纯林>油松-锐齿栎混交林>红桦纯林。不同森林类型枯落物持水率在浸泡吸水阶段均呈快速吸水(0~1 h)、缓慢吸水(1~12 h)和趋于饱和(>12 h)3个阶段,其下降速率在静置失水阶段则受环境因子调控保持稳定。枯落物持水能力主要由枯落物蓄积量、鲜重、最大持水率以及坡度、林龄、林分密度等因素决定,土壤层持水能力则主要受土壤非毛管孔隙度、土壤深度和海拔的影响。研究明确了不同森林类型枯落物及土壤层持水能力的差异,并揭示了其主要影响因素,为区域水源涵养林经营管理和水源涵养功能提升提供了科学依据。

       

      Abstract: Existing studies on the water conservation function of forests in the Qinling region have primarily focused on regional-scale simulations, with limited attention paid to the differences and influencing factors of litter and soil water-holding capacities among different forest types at the stand scale. This has resulted in an unclear understanding of the functional mechanisms of the "Qinling Water Tower". In this study, based on field observations and plot investigations, we quantitatively compared the litter and soil water-holding characteristics of five dominant forest types within the Qinling Ecological Station. Correlation analysis was used to identify the key factors influencing water-holding capacity. The results showed that the total water-holding capacity of the litter and soil layers at the Qinling ecological station ranged from 296.74 to 414.74 t/hm2, with the order being Picea wilsonii>Pinus tabuliformis>Quercus aliena var. acuteserrata>Pinus tabuliformis-Quercus aliena var. acuteserrata mixed forest>Betula albosinensis. Litter water absorption during the soaking phase exhibited three stages: rapid absorption (0~1 h), slow absorption (1~12 h), and saturation (>12 h). Meanwhile, the water loss rate during the static drainage phase remained relatively stable under the influence of environmental factors.Litter water-holding capacity primarily depended on litter storage, fresh weight, maximum water-holding capacity, slope, stand age, and stand density, while soil water-holding capacity was mainly influenced by soil non-capillary porosity, soil depth, and altitude. This study clarifies the differences in litter and soil water-holding capacities among different forest types and identifies their dominant influencing factors, providing a scientific basis for regional water conservation management.

       

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