木兰围场3种典型林分枯落物及土壤持水能力

Water-holding Capacity of Three Typical Forest Litter and Soil in Mulan-weichang

为探讨木兰围场华北落叶松人工林、白桦华北落叶松次生林和白桦次生林枯落物和土壤的持水规律。以这3种典型林分的枯落物和土壤为研究对象,采用室内浸水法和环刀法分别研究3种林分枯落物和土壤的持水特性。结果表明:3种林分枯落物的蓄积量表现为华北落叶松人工林(18.84t/hm2)>白桦华北落叶松次生林(15.28t/hm2)>白桦次生林(9.53t/hm2)。白桦华北落叶松次生林的枯落物最大持水量最大,为31.10t/hm2;而白桦次生林最大持水量最小,为21.40t/hm2,枯落物持水量与浸水时间呈对数关系,关系式为Q=aln(t)+b;吸水速率与浸水时间呈幂函数关系,关系式为V=ktn。枯落物在前0.5h内吸水速率最大,在4h左右时下降速度明显减缓,在24h时的吸水速率基本趋于0。3种林分枯落物有效拦蓄量表现为华北落叶松人工林(23.42t/hm2)>白桦华北落叶松次生林(20.24t/hm2)>白桦次生林(15.51t/hm2)。在0-60cm的土壤层中,华北落叶松人工林土壤容重均值最大,为1.32g/cm3;白桦华北落叶松次生林最小,为1.10g/cm3。白桦华北落叶松次生林的土壤总孔隙度均值最大,为53.65%;华北落叶松人工林最小,为47.45%。土壤的毛管孔隙度均值呈现出白桦华北落叶松次生林(42.61%)>华北落叶松人工林(40.68%)>白桦次生林(36.01%)的趋势。白桦次生林的土壤有效持水量最大,为175.99t/hm2,华北落叶松人工林最小,为67.70t/hm2。综合3种林分枯落物层和土壤层的持水能力,可知白桦华北落叶松次生林储水能力强于华北落叶松人工林和白桦次生林。

To export the water-holding rule of litter and soil of Larix principis-rupprechtii plantations,Betula platyphylla and Larix principis-rupprechtii secondary forest and Betula platyphylla secondary forest in Mulan-weichang.A study of hydrological effects of litter and soil was carried out in the three typical forest of Mulan-weichang.The water-holding capacity of litter and soil were studied respectively by using indoor immersion method and cutting ring method in the three typical forest.The result showed that litters amount of Larix principis-rupprechtii plantations（18.84t/hm^2）〉Betula platyphylla and Larix principis-rupprechtii secondary forest（15.28t/hm^2）〉Betula platyphylla secondary forest（9.53t/hm^2）in the three typical forest.The maximum water-holding capacity of litter in Betula platyphyllaand Larix principis-rupprechtii secondary forest was 31.10t/hm^2,Betula platyphyllasecondary forest was the lowest to 21.40t/hm^2.The water-holding capacity of litters and immersion time had logarithm relationship,the relational expression was Q=aln（t）＋b;the relationship of absorption rate and immersion time was power function,the relational expression was V=ktn.The absorption rate of litter was maximal before the half-hour,the rate obviously slowed down at about 4h,basically,the absorption rate tended to zero at the 24 h.The effective impoundment of water of three forest litters showed that Larix principis-rupprechtii plantations（23.42t/hm^2）〉Betula platyphylla and Larix principis-rupprechtii secondary forest（20.24t/hm^2）〉Betula platyphylla secondaryforest（15.51t/hm^2）.In the soil layer of 0-60 cm,the mean of soil bulk density was the maximum to 1.32g/cm^3 in the Larix principis-rupprechtii plantations;Betula platyphylla and Larix principis-rupprechtii secondary forest was the minimum to 1.10g/cm^3.The mean of soil total porosity was the maximum to 53.65%in the Betula platyphylla and Larix principis-rupprechtii secondary forest;Larix principis-rupprechtii plantations was the lowest to 47.45%.The mean of soil capillary porosity showed Betula platyphylla and Larix principis-rupprechtii secondary forest（42.61%）〉Larix principis-rupprechtii plantations（40.68%）〉Betula platyphylla secondary forest（36.01%）.The effective water-holding capacity of soil was the maximum to 175.99t/hm^2 in Betula platyphylla secondary forest,Larix principis-rupprechtii plantations was the lowest to 67.70t/hm^2.Generally,the study result showed that the water-holding ability of litter and soil in Betula platyphylla and Larix principis-rupprechtii secondary forest was stronger than Larix principis-rupprechtii plantations and Betula platyphylla secondary forest.