高寒地区土地利用方式对土壤碳氮含量的影响

本文分析高寒地区不同土地利用方式下，土壤的更新、恢复与重建过程中土壤碳氮含量的变化；对高寒地区的小蒿草原生草地天然群落、多叶老芒麦+冷地早熟禾混播人工群落、小嵩草退化群落的土壤养分的含量进行分析；0~20 cm处土壤全氮水平、有机氮含量依次为原生小嵩草群落(2.6495、1.5905 g/kg)>退化草地群落(2.5490、1.5700 g/kg)>人工草地群落(2.34、1.5015 g/kg)；0~20 cm土层中全碳、有机碳的含量依次为原生小嵩草群落(15.6355、14.37 g/kg)>退化草地群落(13.609、11.359 g/kg)>人工草地群落(10.876、10.810 g/kg)，植物群落的C/N均为原生小嵩草群落（5.90）>退化草地群落（5.10）>人工草地群落（4.65）；本研究表明原生植物群落对氮的吸收能力最强，具有最高的有机质保持能力维持原生小嵩草群落的生态稳定性，为高寒地区土壤的更新、土壤的恢复与重建具有极其重要的意义。

Effects of Different Land-use Types on Soil Carbon and Nitrogen Contents in Alpine Region of Tibetan Plateau

Three different land-use types, primary vegetation（PV） 、 artificial grassland（AG）, degraded vegetation （DV） in alpine region of Tibetan Plateau. In the paper, soil bulk density, soil moisture content, soil pH, soil porosity, soil organic nitrogen, total nitrogen, soil organic carbon, nitrify nitrogen, ammonium nitrogen contents of the 0-10, 10-20 cm soil layers were investigated. It is suggested that： The content of soil organic nitrogen and total nitrogen in the 0-20 cm soil layer varied in the order of PV（2.6495 、 1.5905 g/kg） DV （2.5490 、 1.5700 g/kg） AG （2.34 、 1.5015 g/kg） ; the content of soil total carbon and organic carbon in the 0-20cm soil layer varied in the order of PV （15.6355 、 14.37 g/kg） DV （13.609 、 11.359 g/kg）AG （10.876 、 10.810 g/kg）. The ratio of C/N in the 0-20 cm soil layer varied in the order of PV （5.90）DV （5.10）AG （4.65）. The PV community had the best ability to maintain the soil organic matter. To maintain the stability of primary vegetation community, that was important for replacement, recovery and reconstruction of soil in alpine region of Tibetan Plateau.