帽儿山林场不同河岸带植被类型土壤水分-物理性质

Water-physical Properties of Soils under Different Vegetation Types in Riparian Areas in Maoershan Experimental Forest Farm of Shangzhi City,Heilongjiang Province

利用环刀法对帽儿山林场内的森林、灌丛、草地3种河岸带植被类型土壤水分-物理性质进行分析,结果表明:同一植被类型河岸带,土壤密度随土层深度的增加而增大,持水量和孔隙度、渗透速度随土层加深而减小,持水能力随土壤深度的增加而减弱;随着与溪流距离的增加,土壤密度、孔隙度、渗透性有增加的趋势,而持水量有减小的趋势,但无显著差异。不同类型河岸带中,森林、灌丛、草地河岸带的总孔隙度都大于60%,毛管孔隙度超过50%,其中森林河岸带的土壤密度0.8g/cm3左右,显著的低于灌丛和草地河岸带(1.0g/cm3左右),森林河岸带土壤渗透速度接近于2.0mm/min,饱和持水量大于80%,毛管持水量70%左右,都显著高于灌丛、草地河岸带。其中,草地河岸带非毛管孔隙度为5%左右,而渗透速度仅为0.1mm/min。由于森林河岸带在土壤透气性、持水性、入渗性能方面明显好于灌丛和草地,对于溶解在地表径流中的污染物消除应当具有更高的效率。

An experiment was conducted to study the water-physical properties of soils under three different vegetation types （for- est, shrub and grassy riparian areas） by the method of intact soil core. Results show that soil density is higher in the lower layer than in the upper one in riparian area with the same vegetation type, while water holding capacity, porosity and permeability decrease with increasing depth of soil. Soil density, porosity, permeability tend to increase as the distance from sampling position to stream increase, while water holding capacity tends to decrease. Soil total porosity for all the three vegetation types is greater than 60%, and the capillary porosity more than 50%. Significant differences in soil density were found between riparian areas with different vegetation types, with the lowest （0.8 g/cm^3 ） in the forested riparian area, which is lower than that under shrub and grassy vegetation （ 1.01 g/cm^3 and 0.91 g/cm^3 , respectively）. The permeabili- ty, water holding capacity and capillary porosity in the forested riparian soil were 1.81 mm · min^-1 , 89.33%, 77.14%, respectively, which are significantly greater than those in shrub and grassy riparian zones. Soil capillary porosity and permeability in the grassy 5parian zone was only 5.41% and 0.1 mm·min^-1, respectively. The forested riparian soil was found to be superior in aeration, water holding capacity and permeability compared with shrub and grass riparian, and it may be more efficient in removal of contaminants dissolved in surface runoff.