我国南亚热带几种人工林生态系统碳氮储量

以我国南亚热带格木(Erythrophleumfordii)、红椎(Castnopsis hystrix)和马尾松(Pinus massoniana)人工林为研究对象,对其碳氮储量及分配格局进行研究.结果表明,不同树种体内碳的分布与器官年龄的关系不明显,而氮的分布与年龄的关系则较为密切,表现为幼嫩器官中的氮含量大于老化器官,而老化器官的C/N比值大于幼嫩器官.格木人工林生态系统内各组分的氮含量均高于其他两种人工林生态系统,并且3种人工林生态系统碳氮在土壤表层具有明显的富集作用.格木、红椎和马尾松人工林碳储量分别为236.22、267.84、200.57 t/hm2,氮储量分别为17.91、12.38、10.59 t/hm2.乔木层碳储量分别占42.57％、36.31％和40.28％,0-100 cm土壤碳储量分别占55.77％、62.52％和57.83％；氮储量则是土壤占绝对优势,分别为92.00％、93.72％和95.53％.说明3种人工林生态系统碳氮储量主要分布在土壤中,且红椎人工林生态系统具有较高的固碳能力.

Carbon and nitrogen storage under different plantations in subtropical south China

Carbon and nitrogen storage in different plantation ecosystems of Erythrophleum fordii, Castanopsis hystrix and Pinus massoniana in subtropical south China were studied. The results showed that the allocation of C in the organs of the different tree species had no significant correlation with their age, while that of N had closer relationship with the age. The N concentration in young organs was higher than that in aged ones and the C/N ratio was higher in aged organs than that in young ones. The N concentration was higher in all components of the nitrogen-fixing species (E. fordii plantation) than that in other species (C. hystrix and P. massoniana plantations). There was an obvious enrichment of C and N in the topsoil of the plantation ecosystems. The total ecosystem carbon storage of E. fordii, C. hystrix and P. massoniana plantations was 236.22 t/hm², 267.84 t/hm² and 200.57 t/hm² and nitrogen storage was 17.91 t/hm², 12.38 t/hm² and 10.59 t/hm², respectively. Carbon storage of tree layer occupied 42.57%, 36.31% and 40.28% while 0-100 cm soil occupied 55.77%, 62.52% and 57.83%, respectively. Nitrogen storage of soil occupied 92.00%, 93.72% and 95.53%. Our study indicated that most ecosystem carbon and nitrogen storage of the plantations stored in soil. Carbon sequestration ability of C. hystrix plantation is higher compared to other two plantations.