研究森林土壤水文功能及影响因素对区域森林水源涵养及水土保持功能评价具有重要意义。选择秦岭火地塘不同海拔7种典型森林类型进行土壤取样,通过室内环刀法、重铬酸钾氧化法、筛选法、定水头法分别测定不同森林类型的土壤理化性质、持水特性、大孔隙和饱和导水率等水文功能指标并进行统计分析。结果表明:1)各森林类型土壤持水能力均随土层深度增加而降低,其田间持水量为29.95%~76.66%;位于较高海拔(>1 900 m)的青杄林、冷杉林、铁杉林和华北落叶松林具有较高的土壤持水能力,而位于低海拔(1 400~1 700 m)的油松林、日本落叶松林和锐齿槲栎林则具有较低的土壤持水能力,但高海拔森林(除铁杉林外)土壤的蓄水能力小于低海拔森林土壤;2)不同森林类型土层的土壤饱和导水率为0.02~9.82 mm/min,其平均饱和导水率大小依次为锐齿槲栎林>铁杉林>日本落叶松林>青杄林>油松林>华北落叶松林>冷杉林;3)森林土壤持水能力与土壤容重、总孔隙度和有机质含量显著相关,土壤饱和导水率则与单位面积土壤大孔隙数量、砾石含量、粉粒和黏粒含量显著相关,且森林土壤饱和导水率与大孔隙数量呈显著正相关关系。

The study of forest soil hydrology functions and their influencing factors is of great significance for regional forest water conservation and ecological evaluation of soil and water conservation.Soil samples were collected from seven typical forest types at different elevations in Huoditang,Qinling Mountains.The soil physical and chemical properties,water retention characteristics,macropore and saturated hydraulic conductivity from different forest types were determined by the ring knife method,potassium dichromate oxidation method,screening method and fixed water head method.The hydrological function indices were then statistically analyzed.1)Soil water holding capacity of all forest types decreases with the increasing soil depth,and the field water holding capacity ranges from 29.95% to 76.66%.The soil water holding capacity of the Picea wilsonii forest,Abies fabri forest,Tsuga chinensis forest and Larix gmelinii var.principis-rupprechtii forest located at a higher altitude(>1 900 m)is greater than that of Pinus tabuliformis forest,Larix kaempferi forest and Quercus aliena var.acuteserrata forest at low altitude(from 1 400 to 1 700 m)was lower.Conversely,the water holding capacity of higher altitude forest types(except Tsuga chinensis forest,which has the largest water storage capacity)is lower,while that of lower altitude forest types is higher.2)The saturated hydraulic conductivity of the soil layer of different forest types ranges from 0.02 to 9.82 mm/min.The average saturated hydraulic conductivity is as follows:Quercus aliena var.acuteserrata forest>Tsuga chinensis forest>Larix kaempferi forest>Picea wilsonii forest>Pinus tabuliformis forest>Larix gmelinii var.principis-rupprechtii forest>Abies fabri forest.3)Forest soil water holding capacity was significantly correlated with soil bulk density,total porosity,and organic matter content.Soil saturated hydraulic conductivity was significantly correlated with soil macropore,gravel content,silt and clay content.Moreover,forest soil saturated hydraulic conductivity was significantly positively correlated with the number of macropore.