衡阳紫色土丘陵坡地不同植被恢复过程中土壤水文效应

Soil hydrological function at different vegetation restoration stages in purple soil slopelands in Hengyang

  • 摘要: 采用空间代替时间序列方法, 对衡阳紫色土丘陵坡地不同植被恢复阶段土壤层的水文效应进行研究。结果表明: (1)从裸露地、草坡、灌草、灌丛至乔灌恢复阶段, 土壤蓄水性与渗透性显著增加(P<0.05); (2)Horton入渗模型对各植被恢复阶段的入渗过程拟合效果较好(R2≥0.765), 有较好的适用性; (3)土壤理化性状、植被根系显著影响土壤的渗透性能, 植被根系提高土壤入渗性能的实质是: ≤1 mm细根可有效改善土壤的理化性状; (4)基于主成分分析, 从裸露地、草坡、灌草、灌丛至乔灌恢复阶段, 土壤综合水文效应显著提高(P<0.05)。此研究结果将丰富该地区植物生态学与恢复生态学的内容, 并为衡阳紫色土丘陵坡地生态系统的恢复与重建提供重要依据。

     

    Abstract: Soil hydrological functions at different vegetation restoration stages in purple soil slopelands in Hengyang were explored by using spatial series in replace of temporal series. The results showed significant increases (P < 0.05) in soil water storage capacity and permeability from bare-land (CK) to grassland stage (Ⅰ), bushwood and grassland stage (Ⅱ), bushwood (Ⅲ) and to arbor and bushwood stage (Ⅳ). The orders of initial and stable infiltration rates were respectively arbor and bushwood stage (IV) (1 347.09 mm·h-1 and 338.00 mm·h-1) > bushwood stage (III) (876.98 mm·h-1 and 323.30 mm·h-1) > bushwood and grassland stage (II) (834.99 mm·h-1 and 320.64 mm·h-1) > grassland stage (I) (729.09 mm·h-1 and 306.18 mm·h-1) > bare-land stage (CK) (412.43 mm·h-1 and 122.98 mm·h-1). The fitness of Horton infiltration model derived for soil infiltration at each stage was strong (R2 ≥ 0.765), and the model was highly applicable. Soil infiltration capability was greatly affected by soil physio-chemical properties and root system. Fine roots (≤ 1 mm in diameter) was effective in improving soil physio-chemical properties, and soil infiltration capability increased with increasing density of the fine roots. Principal component analysis (PCA) showed that from bare-land stage to grassland stage, bushwood and grassland stage, bushwood stage to arbor and bushwood stage, hydrological properties significantly increased (P < 0.05). The order of comprehensive hydrological function was arbor and bushwood stage (IV) (57.45) > bushwood stage (III) (48.54) > bushwood and grassland stage (II) (40.68) > grassland stage (36.81) (I) > bare-land stage (CK) (31.43). The study enriched and broadened vegetation ecology and ecological restoration in the area. It also provided the critical basis for vegetation restoration and reconstruction of ecosystem in purple soil slopelands in Hengyang.

     

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