南亚热带杉木林改造对土壤及凋落物持水能力的影响

对杉木林进行改造，是提高林分质量和生态效能的重要措施。该文研究了杉木林改造前期对土壤及凋落物持水能力的影响。结果表明，在杉木林改造前期，不同林龄段试验林间土壤容重、孔隙度和土壤持水量差异不显著（P > 0.05），但随林龄的增加呈上升趋势，土壤涵养水源能力有所增加。凋落物量及其持水能力随改造林龄的增加呈上升趋势，9～11 a林龄试验林凋落物及持水能力显著高于3～5 a林龄试验林（P < 0.05），而其凋落物持水能力与5～7 a林龄试验林差异不显著（P > 0.05）。浸水试验表明，凋落物持水率随浸泡时间的增加呈对数曲线增长，吸水速率与浸泡时间呈反函数关系。凋落物最大持水量远小于土壤最大持水量，仅为土壤的0.18%，0.11%和0.08%，土壤为森林涵养水源的主体。通过分析试验林土壤和凋落物持水能力发现，杉木+米老排+阴香+山杜英+枫香、杉木+火力楠+米老排+阴香+红荷和杉木+木荷+山杜英+香椿+山黄麻改造模式对土壤和凋落物持水能力影响效果较好，其水文功能较高。

Effects of Cunninghamia lanceolata Stand Reconstructing on the Water-Holding Capacities of Soil and Litter in Southern Subtropical Region

Transformation of Cunninghamia lanceolata plantation was an important measure to improve forest stand quality and its ecological functions. In this paper, transformation methods of Cunninghamia lanceolata plantation in Foshan, were taken as the example to study the water-holding capacities of soil and litter with different forest ages. The bulk density, porosity and water holding capacity of soil for experimental forest with different age segments were not significant (P < 0.05), while those parameters of soil rose with the extension of forest ages, and water conservation of soil was improved. Litter biomass and water-holding capacity of litter increased with the increase of forest ages. Biomass and water-holding capacity of litter in experimental forest with the ages of 9～11 years were significantly higher than those of litter in experimental forest with 3～5 years (P < 0.05), while water-holding capacity of litter was not significant with 3～5 years experimental forest. The litter soaking experiments showed that the water holding capacity increased with soaking time, following a logarithmic curve, while water absorption rate decreased with soaking time, following inverse function relationship. The maximum water-holding capacity of litter layer was much less than the soil layer, which accounted for 0.18%, 0.11% and 0.08% of the maximum water-holding capacities of soil. Forest soils become the subject of water conservation. The improvement methods of Cunninghamia lanceolata, Mytilaria laosensis, Cinnamomum burmannii, Elaeocarpus sylvestris, Liquidambar formosa and Cunninghamia lanceolata, Michelia macclurei, Mytilaria laosensis, Cinnamomum burmannii, Schima wallichii and Cunninghamia lanceolata, Schima superba, Elaeocarpus sylvestris, Toona sinensis, Trema orientalis showed good water holding capacity of soil and litter by analyzing water holding capacity of soil and litter.This study results can provide scientific basis for planting tree selection, near natural transformation of stand, forest management and assessment of service function of forest ecosystem.