武夷山不同海拔典型森林土壤有机碳和全氮储量分布特征

为探究武夷山森林土壤碳氮储量的分布特征,以武夷山国家公园不同海拔高度(600,1 000,1 400 m)的典型森林土壤为研究对象,研究土壤有机碳和全氮含量及储量随海拔高度的变化规律,分析了影响土壤有机碳和全氮储量变化的因子。结果表明:随着海拔的升高,土壤有机碳和全氮的含量在0—5 cm土层和5—10 cm土层变化规律不同,5—10 cm土层的土壤碳氮含量随海拔变化趋势更为明显,而0—5 cm土层的土壤碳氮含量表现为1 000 m海拔较高; 海拔1 000 m的土壤C/N明显高于海拔1 400 m和600 m; 在土壤有机碳和全氮储量方面,1 400 m明显高于1 000 m和600 m,且高海拔区域土壤碳氮储量的变化幅度显著大于低海拔区域,两土层间差异不显著; 相关分析和RDA分析表明细根C/N和土壤温度是影响土壤有机碳和全氮储量的主导因子。综上所述,土壤有机碳和全氮的分布随海拔升高并非线性增长,受到气候、植被特征及土壤状况的综合影响,高海拔地区土壤碳氮储量对气候变化的响应更为敏感。

Distribution Characteristics of Soil Organic Carbon and Total Nitrogen Storage in Typical Forest Soils at Different Altitudes in Wuyishan Mountain

In order to explore the distribution characteristics of forest soil carbon and nitrogen storage in Wuyishan Mountain, typical forest soils at different altitudes(600, 1 000, 1 400 m)were selected as research objects. The changes of soil organic carbon and total nitrogen contents and reserves with altitude were studied, and the factors affecting the changes of soil organic carbon and total nitrogen reserves were analyzed. The results show that: with the increase of altitude, the changes of soil organic carbon and total nitrogen contents in 0—5 cm soil layer and 5—10 cm soil layer were different; the changes of soil carbon and nitrogen contents in 5—10 cm soil layer were more obvious with the increase of altitude, while the soil carbon and nitrogen contents in 0—5 cm soil layer were higher at 1 000 m altitude; soil C/N at 1 000 m was significantly higher than that at 1 400 m and 600 m; soil organic carbon and total nitrogen storage at 1 400 m were significantly higher than those at 1 000 m and 600 m; the variation ranges of soil carbon and nitrogen storage at high altitude were significantly greater than those at low altitude, and there was no significant difference between the two soil layers; correlation analysis and RDA analysis showed that fine root C/N and soil temperature were the dominant factors affecting soil organic carbon and total nitrogen storages. In conclusion, the distribution of soil organic carbon and total nitrogen does not increase linearly with the elevation, but is affected by the climatic and vegetation characteristics and soil conditions. Soil carbon and nitrogen storage at high altitude is more sensitive to climate change.