摘要
为了解喀斯特生态系统退化过程中树木细根生物量和土壤养分的变化,选择贵州中部喀斯特山地乔木林、灌木林和灌草丛3种植被生态系统,比较分析不同深度(0～5 cm、5～10 cm和10～15 cm)土壤细根数量及其养分情况.结果表明:树木细根主要分布在0～10 cm土层,并随土层加深而减少.在0～10 cm土层中,乔木林、灌木林和灌草丛的活细根生物量分别占0～15 cm总细根生物量的42.78%、56.75%和53.38%,总活细根生物量的83.36%、86.91%和93.79%.不同植被下优势种植物细根生物量存在差异.0～5 cm土层乔木林活细根氮素和磷素储量均显著高于灌草丛和灌木林(P<0.05),但灌木林和灌草丛间没有差异;5～10 cm土层乔木林活细根氮和磷储量显著高于灌草丛和灌木林(P<0.05),灌木林下又显著高于灌草丛下(P<0.05).0～10 cm土层的活细根生物量与植株地上部分生物量呈正相关,植物叶片氮、磷养分含量与细根比根长呈显著的负相关,说明细根的养分储量对地上生物量的建成和生态系统功能的发挥具有重要作用.
The degeneration of karst ecosystem is closely associated with the reduction of soil nutrients and fine root biomass,and the retention of soil nutrients is of significance in sustaining ecosystem functioning.To understand the changes in the fine root biomass and soil nutrient retention in degenerated karst ecosystems,a comparative study was conducted with three typical vegetation stands（forest,shrub,and shrub-grass） in Central Guizhou of Southwest China.Soil samples with fine roots were collected from the depths 0-5 cm,5-10 cm,and 1015 cm,with the related indices of fine roots and nutrients measured.In the three stands,fine roots dominantly distributed in 0-10 cm soil layer,and decreased sharply with soil depth.The living fine root biomass in 0-10 cm soil layer under forest,shrub,and shrub-grass occupied 83.36%,86.91%,and 93.79% of the total fine root biomass,and 42.78%,56.75%,and 53.38% of the total living fine root biomass within the 0-15 cm soil layer,respectively.The fine root biomass of predominant plant species varied with vegetation types.The N and P storage of the living fine roots in 0-5 cm soil layer under forest stand was significantly higher than those under shrub stand and shrub-grass stand,and no significant differences were observed between the latter two stands.However,the N and P storage of the living fine roots in 5-10 cm soil layer under different stands decreased in the order of forest shrub shrub-grass（P0.05）.There was a significant positive correlation between the plant aboveground biomass and the living fine root biomass in 0-10 cm soil layer,and a significant negative correlation between the N and P contents of plant leaves and the specific length of living fine roots,illustrating that the nutrient uptake and retention by the living fine roots could have particular importance in the aboveground biomass establishment and ecosystem functioning.
出处
《应用生态学报》
CAS
CSCD
北大核心
2010年第8期1926-1932,共7页
Chinese Journal of Applied Ecology
基金
国家基础研究发展计划重点项目(2006CB403205)资助
关键词
喀斯特生态系统
细根
养分储量
细根生物量
植被退化
karst ecosystem
fine root
nutrient storage
root biomass
vegetation degeneration.
