不同林龄白桦次生林土壤特性及其水源涵养功能

Soil properties and water conservation function of Betula platyphylla secondary forest with different stand ages

以小兴安岭地区4个林龄的白桦次生林为研究对象,对其土壤特性、土壤贮水性能、凋落物持水量进行研究。结果表明：白桦次生林凋落物的蓄积量、最大持水量均以38 a为最大,70 a相对较低,凋落物蓄积量与最大持水量有显著正相关关系;土壤非毛管孔隙度随林龄变化呈波动性变化,38 a白桦次生林0-30 cm土层非毛管孔隙最大,有利于降水的下渗,而25 a白桦次生林0-30 cm土层非毛管孔隙最小,不利于水分下渗。土壤水源涵养功能大小排序为70 a（3 628.445 t/hm^2）〉56 a（3 524.015 t/hm^2）〉25 a（3 433.626 t/hm^2）〉38 a（3 275.820 t/hm^2）。

Soil characteristics, water holding capacity of litter and soil water storage properties of four different ages of Betula platyphylla secondary forest in Xiaoxing＇an Mountain were analyzed. The results showed that： the volume and maximum water holding capacity of litter in 38 years old of Betula platyphylla secondary forest were biggest, while that in 70 years old were lower, relatively. There were significant positive correlation between the volume and maximum water holding capacity of litter. And the non-capillary porosity was fluctuating changes with ages. It was beneficial to rainfall infiltration through the 0 - 30 cm soil layer in 38 years old of the Betula platyphylla secondary forest, while that in 25 years old with the smallest non-capillary porosity is not beneficial to rainfall infiltration according to the soil bulk density and non-capillary characteristics analysis. Based on the investigated data, the decreasing order of soil water conservation function of the four ages of the Betula platyphyUa secondary forest was 70 a （3 628.445 t/hm^2）, 56 a （3 524.015 t/ hm^2）, 25 a （3 433.626 t/hm^2）, 38 a（3 275.820 t/hm^2）.