大伙房水库流域不同植被类型枯落物层和土壤层水文效应

为了研究大伙房水库流域森林生态系统枯落物层和土壤层水文效应,以流域内3种不同植被类型为研究对象,采用浸泡法、环刀法对其枯落物层和土壤层水文功能进行定量研究。结果表明:(1)3种植被类型枯落物蓄积量为23.20～39.11t/hm~2,表现为刺槐天然次生林油松人工林落叶松人工林,且阔叶林枯落物半分解层蓄积量大于未分解层,而针叶林则相反。(2)枯落物层最大持水量为50.24～109.19t/hm~2,有效拦蓄量为41.70～90.71t/hm~2,均表现为刺槐天然次生林油松人工林落叶松人工林,刺槐天然次生林枯落物层持水功能较好。(3)枯落物未分解层、半分解层分别在浸水10,8h基本达到饱和,持水量与浸水时间呈明显对数关系(R20.91);枯落物在浸水1h内吸水速率变化最大,4h左右吸水速率明显减缓,吸水速率与浸泡时间呈明显幂函数关系(R20.93)。(4)3种植被类型土壤容重均值变化范围为1.10～1.25g/cm~3,总孔隙度变化范围为27.96%～30.19%,土壤有效持水量变化范围为21.11～29.39t/hm~2,不同植被类型土壤层持水能力表现为刺槐天然次生林油松人工林落叶松人工林,土壤入渗速率与入渗时间呈明显幂函数关系(R20.90)。综合3种植被类型枯落物层及土壤层水文功能表明刺槐天然次生林的水源涵养功能较强,建议在该流域加强天然次生林的保护和恢复。

Hydrological Effects of Litters Layer and Soil Layer in Different Vegetation Types in Dahuofang Watershed

A pilot study of hydrological effects of litters layer and soil layer was carried out in three different vegetation types (Pinus tabulaeformis plantation, Larix gmelinii plantation and Robinia pseudoacacia natural secondary forests) in Dahuofang Watershed. The hydrological functions of litters layer and soil layer were quantitatively determined by immersion method and cutting-ring method. The results showed that:(1) The litter volume of three different vegetation types was about 23.20~39.11 t/hm², which followed the order of R. pseudoacacia natural secondary forests > P. tabulaeformis plantation > L. gmelinii plantation, and the volume of semi-decomposed litter was higher than that of undecomposed litter in broad-leaved forest, while the opposite trend was observed in coniferous forest. (2) The maximum water-holding capacity and modified interception amount was 50.24~109.19 t/hm² and 41.70~90.71 t/hm², respectively, both of them followed the order of R. pseudoacacia natural secondary forests > P. tabulaeformis plantation > L. gmelinii plantation. (3) Semi-decomposed litter could be saturated in 8 hours and undecomposed litter reached saturation in 10 hours, the water-holding capacity had logarithmic relationship with soaking time (R²>0.91), the absorption rate changed the most within the first 1 hour of soaking, and it obviously slowed down after 4 hours, and there was a power function relationship between water absorption rate and soaking time (R²>0.93). (4) The average soil bulk density of the three vegetation types ranged from 1.10 g/cm³ to 1.25 g/cm³, total porosity was about 27.96%~30.19%. The soil effective water-holding capacity was about 21.11~29.39 t/hm², which followed the order of R. pseudoacacia natural secondary forests > P. tabulaeformis plantation > L. gmelinii plantation. A significant power function relation between infiltration rate and infiltration fitting time was found (R²>0.90). Considering the hydrological effects of litters layer and soil layer of three different vegetation types, the water conservation function of R. pseudoacacia natural secondary forests was stronger than that of the other vegetation types, which suggested that more attention should be paid to protect and restore the natural secondary forests in the Dahuofang watershed in order to improve water conservation function of forest.