涪江流域丘陵区不同植被类型水源涵养功能

Water Conservation Capacity of Five Main Forest in the Hilly Area of Fujiang River Basin

采用野外调查和水浸法,研究涪江流域丘陵地区5种典型植被系统的雨水截留能力、凋落物蓄积量和持水能力、土壤物理特性、蓄水能力和渗透性能,并基于坐标综合评定法对不同植被类型的水源涵养和保土功能进行综合评价。各植被类型降雨截留量、凋落物蓄积量和持水量均以阔叶灌丛最高,草地最低,阔叶灌丛的平均截留量、凋落物蓄积量和持水量分别为草地的4.9,2.9,1.8倍。不同植被类型的土壤容重和孔隙度差异较大,容重表现为草地>针叶林>针阔混交林>常绿阔叶林>阔叶灌丛;总孔隙度为阔叶灌丛>常绿阔叶林>针阔混交林>针叶林>草地。土壤渗透速率和贮水能力随土壤深度增加而降低,以阔叶灌丛最高,其次为常绿阔叶林、针阔混交林、针叶林,草地贮水能力最弱。5种植被类型水源涵养能力依次为阔叶灌丛>常绿阔叶林>针阔混交林>针叶林>草地,阔叶灌丛明显优于其他植被类型。

The canopy interception, litter stock and water holding capacity, soil physical properties, soil storage capacity and permeability in grassland, broad-leaved shrub, evergreen broadleaved forest, evergreen broadleaved and coniferous mixed forest, and coniferous forest were studied in the Fujiang river basin by field survey and water immersion methods. The broadleaved shrub had the highest canopy interception, litter water-holding capacity and litter volume, while the grassland showed the opposite. The average value of canopy interception, litter water-holding capacity and litter volume of the broad-leaved shrub were about 4.9, 2.9, 1.8 times than that of the grassland. Moreover, there were obvious differences in soil bulk density and soil porosity in the different vegetation types. The ranked order of soil bulk density was grassland 〉coniferous forest 〉 evergreen broadleaved and coniferous mixed forest 〉 evergreen broadleaved forest 〉 broadleaved shrub, whereas the total soil porosity showed the opposite trend. In addition, the storage capacity and permeability of soil decreased with the increase of soil depth. The ranked order of the storage capacity and permeability was broadleaved shrub 〉evergreen broadleaved forest 〉evergreen broadleaved and coniferous mixed forest 〉 coniferous forest 〉 grassland. The coordinate composite evaluation indicated that water conservation capacity was broad-leaved shrub 〉 evergreen broadleaved forest 〉 evergreen broadleaved and coniferous mixed forest 〉coniferous forest 〉grassland.