桂西北不同年龄阶段秃杉人工林的水源涵养功能

为探究秃杉人工林水源涵养功能及其变化趋势,以广西南丹县不同年龄阶段(9,17,25,37年生)秃杉人工林为研究对象,采用室内浸泡法和环刀法分别研究4种林分的林冠层、林下植被层、凋落物层和土壤层持水特性。结果表明:(1)秃杉人工林林冠层和林下植物层持水量分别为18.79～28.37,1.27～4.72 t/hm~2,其中林下植物层持水量随林龄增加而显著增大(P0.05);凋落物现存量为2.23～10.67 t/hm~2,最大持水量为5.95～34.15 t/hm~2,随林龄增加而显著增大(P0.05)。(2)不同林龄秃杉林土壤非毛管孔隙度和总孔隙度分别为5.60%～15.68%和48.27%～66.85%,其中0—20,20—40 cm土层非毛管孔隙度和总孔隙度均显著大于40—80 cm土层(P0.05),同时随林龄增加而增大;土壤层(0—80 cm)最大持水量和有效持水量分别为4 196.74～4 416.47,540.13～648.07 t/hm~2,其中0—20,20—40 cm土层最大持水量和有效持水量随林龄增加而增大。(3)9,17,25,37年生秃杉人工林林分的总持水量依次为4 222.43,4 272.55,4 355.29,4 484.32 t/hm~2,随林龄增加而增大。综上,秃杉人工林能够改善土壤结构和水分状况,增强林分水源涵养功能。

Water Conservation Function of Taiwania flousiana Plantations at Different Ages in Northwest Guangxi

In order to study the water conservation function and its change tendencies of Taiwania flousiana plantations, T. flousiana plantations at different ages (9, 17, 25 and 37 years old) in Nandan county of Guangxi were taken as research objects, and the water holding capacities of the canopy, undergrowth vegetation lager, litter lager and soil lager of the T. flousiana plantations were studied by the indoor soaking method and the cutting ring method. The results showed that:(1) The water holding capacity of the canopy and the vegetation layer under canopy for the different ages of T. flousiana plantations ranked 18.79~28.37 and 1.27~4.72 t/hm², respectively. The water holding capacity of the understory vegetation increased significantly with the increasing of forest age (P < 0.05). The litter amount was 2.23~10.67 t/hm², and the maximum water holding capacity was 5.95~34.15 t/hm², which increased significantly with the increasing of forest age (P < 0.05). (2) Soil non-capillary porosity and total porosity of different T. flousiana plantations were 5.60%~15.68% and 48.27%~66.85%, respectively. Soil non-capillary porosity and total porosity in 0-20 and 20-40 cm soil layers were significantly higher than those in 40-80 cm soil layers (P < 0.05), and increased with the increasing of forest age. The maximum water holding capacity and the effective water holding capacity of the soil layer (0-80 cm) were 4 196.74~4 416.47 and 540.13~648.07 t/hm², respectively. The maximum water holding capacity and the effective water holding capacity of the 0-20 and 20-40 cm soil layers increased with the increasing of forest age. (3) The total water storage capacity of 9, 17, 25 and 37 years old T. flousiana plantations were 4 222.43, 4 272.55, 4 355.29 and 4 484.32 t/hm², respectively, which increased with the increasing of forest age. In conclusion, the T. flousiana plantations could improve the soil structure and moisture condition and enhance the water conservation performance of stands.