School of Geographical Sciences, Fujian Normal University, Fuzhou 350117, China.
Key Laboratory for Humid Subtropical Eco-Geographical Processes of Ministry of Education, Fujian Normal University, Fuzhou 350117, China.
Ying Yong Sheng Tai Xue Bao. 2023 Nov;34(11):2898-2906. doi: 10.13287/j.1001-9332.202311.005.
Soil respiration is a key process in forest biogeochemical cycling. Exploring the relationship between plant functional traits and soil respiration can help understand the effects of tree species conversion on soil carbon cycling. In this study, we selected 15 common subtropical tree species planted in the logging site of second-generation Chinese fir forest to measure soil CO emission fluxes, soil physicochemical properties, leaf and root functional traits of each species, and explored the effects of plant functional traits on soil respiration. The results showed that the annual flux of soil CO emissions varied from 7.93 to 22.52 Mg CO·hm, with the highest value under (22.52 Mg CO·hm) and the lowest value under (7.93 Mg CO·hm). Results of stepwise regression analysis showed that the annual flux of soil CO emission decreased with the increases of leaf nitrogen content and fine root diameter, and increased with increasing leaf non-structural carbohydrate. In the structural equation model, leaf non-structural carbohydrate had a direct and significant positive effect on soil CO emission fluxes, while leaf nitrogen content and fine root diameter had a direct negative effect by decreasing soil pH and soluble organic nitrogen content. Plantations of different tree species would affect soil CO emission directly by changing functional traits related to water and nutrient acquisition or indirectly through soil properties. When creating plantations, we should select tree species based on the relationship between plant functional traits and ecosystem functions, with a view to improving forest productivity and soil carbon sequestration potential.
土壤呼吸是森林生物地球化学循环的关键过程。探索植物功能性状与土壤呼吸之间的关系，可以帮助理解树种转换对土壤碳循环的影响。本研究选择了 15 种常见的亚热带树种，种植在第二代杉木林采伐迹地上，测量了各树种的土壤 CO 排放通量、土壤理化性质、叶片和根系功能性状，并探讨了植物功能性状对土壤呼吸的影响。结果表明，土壤 CO 排放的年通量变化范围为 7.93-22.52 Mg CO·hm，其中最高值为 （22.52 Mg CO·hm），最低值为 （7.93 Mg CO·hm）。逐步回归分析结果表明，土壤 CO 排放年通量随叶片氮含量和细根直径的增加而降低，随叶片非结构性碳水化合物的增加而升高。在结构方程模型中，叶片非结构性碳水化合物对土壤 CO 排放通量有直接的显著正向影响，而叶片氮含量和细根直径通过降低土壤 pH 和可溶性有机氮含量对土壤 CO 排放通量有直接的负向影响。不同树种的人工林通过改变与水分和养分获取有关的功能性状，或者通过土壤性质间接影响土壤 CO 排放。在营造人工林时，应根据植物功能性状与生态系统功能的关系选择树种，以提高森林生产力和土壤碳固存潜力。
