柳江流域中游3种人工林的水源涵养功能

以柳江流域中游柳江县3种典型人工林为研究对象,通过野外样地调查和室内实验相结合的方法,从林下草本层、凋落物层、土壤层3个方面研究了不同人工林的水源涵养功能.结果表明:桉树林(巨尾桉Eucalyptus grandis×E.uroplylla)、杉木林(Cunninghamia lanceolata)和马尾松林(Pinus massoniana)林下草本层最大持水量差异不显著,分别为12.12、11.33和8.56 t/hm2;而凋落物层最大持水量的大小顺序为桉树林>马尾松林>杉木林,3种林分间差异显著(P<0.05),分别为13.92、9.86和6.82 t/hm2;3种林分凋落物的持水量和持水率与浸泡时间均呈对数关系,吸水速率与浸泡时间呈幂函数关系;土壤密度随土层厚度的增加而增大,非毛管孔隙度、毛管孔隙度、总孔隙度则相反,均随着土层厚度的增加而减小,桉树林毛管总孔隙度和总孔隙度除外;马尾松林和杉木林60 cm土层的最大持水量差异不明显,但均明显大于桉树林,分别为2968.44、2964.03、2585.20 t/hm2;不同林分的林下层持水总量大小顺序依次为马尾松林(2986.86 t/hm2)、杉木林(2982.17 t/hm2)、桉树林(2611.24 t/hm2),其中土壤层的持水量占99%及以上.

Water Conservation Function of Three Plantations in Middle Reaches of Liujiang River

Three typical plantations in the middle reaches of the Liujiang river basin were used as the re-search object. Through field investigation and experiment, the water conservation function of different plantations was studied from three aspects: the herb layer, the litter layer, and the soil layer. The results indicated that in the herb layer, the maximum water-holding capacity of Eucalyptus grandis × E. urophylla forest, Cunninghamia lanceolata forest and Pinus massoniana forest was 12.12, 11.33, 8.56 t/hm2 respectively, which had no signifi-cant difference. The maximum water-holding capacity of litter layer had the significant difference in the order of Eucalyptus forest (13.92 t/hm2) > P. massoniana forest (9.86 t/hm2) > C. lanceolata forest (6.82 t/hm2). The wa-ter-holding capacity and water-holding rate of litters changed logarithmically, while the water-absorption rate as-sumed a power function of soaking time. Soil bulk density increased from the increase of soil depth, whereas soil non-capillary porosity, capillary porosity and total porosity were reduced from the increase of soil depth, except for capillary porosity and total porosity of Eucalyptus forest. The maximum water-holding capacity of 60 cm soil layer of P. massoniana (2968.44 t/hm2) was a little higher than C. lanceolata forest (2964.03 t/hm2), the lowest was Eucalyptus forest (2585.20 t/hm2). The total maximum water-holding capacity for P. massoniana forest, C. lanceolata forest, Eucalyptus forests was 2986.86, 2982.17, 2611.24 t/hm2, and the order was the same as the soil. The maximum water-holding capacity of soil layer accounted for 99% and above.