北京西山6种天然纯林枯落物及土壤水文效应

Hydrological Effects of Litter and Soil of Six Natural Forests in Xishan Mountainous Area of Beijing

选取北京西山6种天然纯林为研究对象,对其林下枯落物层和土壤水文效应进行研究。结果表明,（1）枯落物总储量变化范围为4.42-9.72t/hm2,大小排序为油松纯林〉栓皮栎纯林〉栾树纯林〉杨树纯林〉侧柏纯林〉银杏纯林;最大持水量变化范围为10.95-25.79t/hm2,其大小排序为油松纯林〉栓皮栎纯林〉栾树纯林〉杨树纯林〉银杏纯林〉侧柏纯林;（2）未分解层枯落物浸泡时间达到6h后,其持水量基本达到最大值,而半分解层出现在浸泡12h左右;在0.5h内吸水速率较高,之后急剧下降,4h后下降速度有所减缓,枯落物吸水速率与浸泡时间呈明显幂函数关系;（3）土壤容重介于0.91-1.41g/cm3之间,总孔隙度介于43.47%-55.1%;（4）土壤有效持水量均值介于14.00-45.67t/hm2之间,最大为银杏纯林,最小为栓皮栎纯林;（5）土壤入渗速率与入渗时间呈明显幂函数关系,6种不同林地土壤稳渗大致在20-25min之间,其中侧柏纯林渗透性最高。

This paper mainly studied hydrological effects of litter layer and soil under 6types of natural forests in Xishan mountainous area of Beijing.The results showed that（1）the total storage capacity of litters of 6natural forests ranged from 4.42t/hm2 to 9.72t/hm2,which listed in the following order：Pinus tabuliformisQuercus variabilis Bl.Koelreuteria paniculataPopulus L.Platycladus orientalisGinkgo biloba,and the maximum water-holding capacity ranged from 10.95t/hm2 to 25.79t/hm2,which listed in the following order：Pinus tabuliformisQuercus variabilis Bl.Koelreuteria paniculataPopulus L.Ginkgo bilobaPlatycladus orientalis.（2）The water-holding capacity reached maximum in 6hfor non-decomposed litters,while reached maximum in 12 hfor semi-decomposed litters,the water absorption rate of forest litters peaked in 0.5h,then rapidly slowed down and the drop speed decreased after 4h,apower function relation existed between water absorption rate and immersion time of forest litters.（3）The average soil bulk density ranged from 0.91g/cm3 to 1.41g/cm3,and total soil porosity ranged from 43.47%to 55.1%.（4）The average soil water-holding capacity ranged from 14.00t/hm2 to 45.67t/hm2,which was the largest in Ginkgo biloba forest and the smallest in Quercus variabilis Bl.forest.（5）A power function relation existed between rate and duration time of infiltration,and steady infiltration of 6forests occurred between 20 min and 25 min,and soil infiltration of Platycladus orientalis was the largest.