广东省蕉岭长潭省级自然保护区森林土壤持水性的垂直空间格局研究

Vertical Pattern of Soil Water-Holding Capacity in Changtan Nature Reserve,Jiaoling,Guangdong

采用DMAP网格法分析广东省蕉岭长潭省级自然保护区森林土壤持水性能的分布格局,探讨了不同深度森林土壤物理性质和持水特征的变化规律.结果表明:森林土壤垂直持水特征表现为:1)土壤最大持水量、土壤通气孔隙度、土壤总孔隙贮水量及非毛管持水量随土层深度的增加而降低,最小持水量和毛管持水量则表现为先降低,再上升;2)综合各持水特性来看,0～25 cm土层与其他层次有显著差异,土壤容重极显著低于其他各土层(P<0.000 1),通气孔隙度、最小持水量、最大持水量、非毛管持水量、总孔隙持水量极显著高于下层土层(P<0.001),毛管持水量与25～50 cm土层持平(P>0.1),50～75和75～100 cm土层则各指标差异不显著(P>0.1).可见,0～25 cm土层比其他土层具有更优的土壤持水性能,对于土壤涵养水源显得尤其重要.

Vertical patterns of soil water-holding capacity in relation to soil physical characteristics were explored based on samples collected from 66 profiles at depths of 0-25, 25-50, 50-75 and 75-100 cm, using a grid system of 150 m × 150 m superimposed in Changtan Nature Reserve according to DMAP method. The following 8 attributes, i. e., bulk density （ BD ）, ventilation porosity （ VP）, water depth （WD） , minimum and maximum water-holding capacity（mWHC and MWHC）, capillary and non-capillary water holding capacity （CWHC and NCWHC）, as well as total water holding capacity （TWHC）, were determined. The results showed that in different soil layers, with the increase of soil depth, VP, mWHC and MWHC, CWHC and NCWHC as well as TWHC decreased but BD increased; highly significant differences （P 〈 0. 001 ） in water-holding capacity among soil physical attributes were found in different land uses, and there were highly significant differences （P 〈 0. 001） in BD, VP, WD, MWHC, TWHC and NCWHC, with the exception of mWHC and CWHC, which were not significantly different in different soil layers. BD, VP, WD, MWHC, CWHC, NCWHC and TWHC showed highly significant differences （P 〈 0. 001 ）, indicating that the 0 -25 cm soil layer had significant implications for soil water conservation as compared with other layers.