青海高寒山区5种林分土壤特性及其水源涵养功能

为定量评价青海省大通县高寒山区不同森林的土壤特性和水源涵养功能,从而为森林的合理空间配置提供理论依据,采用浸水法、环刀法、定水头法、硫酸重铬酸钾法,分别测定5种林分的枯落物性质和0—40cm土层的孔隙度、渗透性及养分状况等。结果表明:(1)枯落物总储量及最大持水量依次为云杉白桦混交林云杉落叶松混交林青海云杉林华北落叶松林白桦林。(2)0—40cm土层的土壤有机质含量平均值依次为云杉落叶松混交林云杉白桦混交林白桦林青海云杉林华北落叶松林。(3)土壤容重随着深度增加而增大,0—40cm土层均值依次为白桦林华北落叶松林云杉白桦混交林青海云杉林云杉落叶松混交林。(4)土壤总孔隙度随土层加深而降低,0—40cm土层均值依次为云杉落叶松混交林青海云杉林云杉白桦混交林华北落叶松林白桦林。(5)0—40cm土层的土壤平均初渗速率和稳渗速率大小依次为白桦林云杉白桦混交林云杉落叶松混交林华北落叶松林青海云杉林。(6)依林地总贮水量评价的水源涵养功能依次为云杉落叶松混交林(4 427.40t/hm~2)青海云杉林(4 365.33t/hm~2)云杉白桦混交林(4 055.04t/hm~2)华北落叶松林(3 729.64t/hm~2)白桦林(2 650.31t/hm~2)。

Soil Characteristics and Water Conservation Function of Five Forest Types in Qinghai Alpine Region

In order to quantitatively evaluate the soil characteristics and water conservation function of different forests in the alpine mountainous areas of Datong County of Qinghai Province and to provide a theoretical basis for reasonable spatial allocation of forests,immersion method,cutting ring method,fixed head method and sulfuric acid potassium dichromate method were used to determine litter properties,soil porosity,soil permeability and soil nutrient status of the 0-40 cm soil layers of five kinds of forest.The results showed that.(1) The litter size and the maximum water holding capacity of the litter in the five forest types were in the order of Picea crassi folia-Betula platyphylla ＞ P.crassi folia-Larix principis-rupprechtill ＞ P.crassi folia forest ＞ L.principis-rupprechtii forest ＞ Betula platyphylla forest.(2) In the 0-40 cm soil layer,the average soil organic matter content was in the order of P.crassifolia-L.principis-rupprechtill ＞ P.crassifolia-B.platyphylla ＞ B.platyphylla forest ＞ P.crassifolia forest ＞ L.principis-rupprechtii forest.(3) In the 0-40 cm soil layer,soil bulk density of five kinds of forest types increased with the increment of soil depth,and followed the order of B.platyphylla forest ＞ L.principis-rupprechtii forest ＞ P.crassifolia-B.platyphylla ＞ P.crassifolia forest ＞ P.crassifolia-L.principis-rupprechtill.(4)In the 0-40 cm soil layer,total porosity of the soil under five forest types decreased with the increment of soil depth.The mean value of soil total porosity was in the order of P.crassifolia-L.principis-rupprechtill ＞P.crassifolia forest ＞ P.crassifolia-B.platyphylla ＞ L.principis-rupprechtii forest ＞ B.platyphylla forest.(5) In the 0-40 cm soil layer,soil average infiltration rate of the five types of forests was in the order of B.platyphylla forest ＞ P.crassifolia-B.platyphylla ＞ P.crassifolia-L.principis-rupprechtill ＞ L.principis-rupprechtii forest ＞ P.crassifolia forest.(6) Based on the total water-holding capacity of litter and soil,water conservation function of the five types of forests followed the order of P.crassifolia-L.principis-rupprechtill (4 427.40 t/hm2) ＞ P.crassifolia forest (4 365.33 t/hm2) ＞ P.crassifolia-B.platyphylla (4 055.04 t/hm2) ＞ L.principis-rupprechtii forest (3 729.64 t/hm2) ＞ B.platyphylla forest (2 650.31 t/hm2).