毛竹扩张对常绿阔叶林土壤性质的影响及相关分析

[目的]为探讨毛竹向邻近常绿阔叶林扩张对土壤性质的影响。[方法]本研究选取江西大岗山森林生态定位站常绿阔叶林、2∶8竹阔混交林、8∶2竹阔混交林和毛竹纯林为研究对象,对土壤有机碳、密度、孔隙度、持水量和贮水量等土壤性质和水分特征进行研究。[结果]常绿阔叶林在毛竹扩张过程中,土壤碳元素含量呈先增后降的趋势。相关分析表明:土壤有机碳与非毛管持水量和现有贮水量呈极显著相关,与土壤密度和总孔隙度呈显著相关,各指标相互作用共同影响了土壤有机碳含量在扩张过程中的变化特征。[结论]常绿阔叶林表层土壤密度、孔隙度和持水量等特征综合优于混交林和毛竹纯林,这为竹鞭扩张后竹笋萌发创造了条件;当常绿阔叶林演替到毛竹纯林时,10 60 cm土壤物理性质和持水能力都有所改善,但有机碳含量降为4个林分最低值,大量竹鞭虽然优化了土壤物理性质,但无性繁殖导致土壤碳元素大量消耗,加之择伐和挖笋等人工干扰,毛竹纯林土壤有机碳含量较低。调节土壤碳含量以及土壤结构和水分特征可能是今后控制毛竹林扩张,维持群落生态系统稳定性的重要生态策略。

The Influence of Phyllostachys edulis Expanding into Evergreen Broadleaf Forest on Soil Property and Its Related Analysis

[Objective]To investigate the influence of Phyllostachys edulis expanding into evergreen broadleaf forest on soil property. [Method]The evergreen broadleaf forest, the mixed forests with bamboo and broadleaf tree in the ratios of 2:8 and 8:2 and the Ph. edulis pure forest at Dagangshan Forest Ecological Station, Jiangxi Province, as sampling sites, the soil properties and water features such as soil organic carbon, bulk density, soil porosity, soil water retaining capacity and soil water storage were studied. [Result]During the process of Ph. edulis expanding, the soil organic carbon content of evergreen broadleaf forest increased at initial and then decreased. Correlation analysis showed that the soil organic carbon was extreme significantly correlated with non-capillary water holding capacity and existing storage capacity, and significantly correlated with soil bulk density and total porosity, the interaction of them affected the expansion process. [Conclusion]Soil bulk density, porosity and water retaining capacity in evergreen broadleaf forest were superior to that in mixed forests and Ph. edulis pure forest, providing the condition for shoot germination after invasion. In the success process from evergreen broadleaf forest to pure Ph. edulis forest, the soil physical properties and water retaining capacity in the soil depth of 1060 cm improved, while the organic carbon content reduced to the lowest in all the forests. Although a large number of rhizome in the soil optimized the soil physical properties, Ph. edulis consumed soil carbon for asexual reproduction, which combined with selective cutting and digging bamboo shoots and other artificial interference, lowering the soil organic carbon of pure Ph. edulis forest. Therefore, the improvement of soil organic carbon content, soil structure and water characteristics may be an important ecological strategy to control the expansion of Ph. edulis and maintain ecosystem stability in the future.