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作 者 ：王启基,李世雄,王文颖,景增春

期 刊 ：生态学报 2008年 28卷 3期 页码：885~894

关键词：江河源区；高山嵩草(Kobresia pygmaea )草甸；覆被变化；植物；土壤；碳；氮储量；

Keywords:Yellow River and Yangtze River source region, Kobresia pygmaea meadow, vegetations cover change, plants, Soil, the reserves of carbon and nitrogen,

摘 要 ：以青海省果洛州藏族自治州甘德县青珍乡高山嵩草Kobresia pygmaea草甸轻度退化草地和重度退化草地为研究对象，通过植物地上部分主要功能群（禾草类、杂类草、莎草类）、植物根系和土壤碳、氮浓度及储量动态研究，结果表明：高寒小嵩草草甸轻度退化草地地上部分主要功能群碳、氮浓度和C∶N比值明显高于重度退化草地的浓度。同一草地类型主要功能群比较，碳、氮浓度依次为杂类草>禾草类>莎草类；植物地上部分的碳、氮浓度明显高于地下根系的碳、氮浓度。重度退化草地植物根系碳、氮浓度高于轻度退化草地植物根系碳、氮浓度。重度退化草地土壤总有机碳浓度显著低于轻度退化草地土壤总有机碳浓度，随着土层的加深碳、氮浓度有减少的趋势。江河源区高山嵩草草甸的土壤有机碳、氮储量最大，植物根系碳、氮储量居中，植物地上部分碳、氮储量最小。重度退化草地总有机碳储量（13554.3 g/m2）较轻度退化草地储量（14669.2 g/m2）下降7.60%。其中，0～40cm土壤层碳储量下降4.10%，植物根系碳储量下降59.97%，植物地上部分碳储量下降15.39%；重度退化草地总氮储量（3780.6 g/m2）较轻度退化草地储量（3352.7 g/m2）高12.76%，其中，0～40cm土壤中总氮储量高13.07%，植物根系全氮储量下降5509%，植物地上部分全氮下降16.00%。由于草地退化损失有机碳11149 kg/hm2，而全氮增加4278 kg/hm2。

Abstract:We conducted this study on lightly and severely degraded Kobresia pygmaea meadow in Qingzhen village, Gande County, Guoluo Prefecture, Qinghai Province. The purpose of this research was to compare carbon, nitrogen concentration, content of unit area and dynamics of aboveground parts, plants roots and soils depths to 40 cm between lightly and severely degraded Kobresia meadow. The results showed that the aboveground tissue C, N concentration and C∶N ratio was significantly higher in the lightly degraded grassland than in the severely degraded grassland. In addition, total carbon and total nitrogen concentration of aboveground tissue were forbs > grasses > sedges at the same grassland type. total carbon and total nitrogen concentration of belowground roots was significantly higher in the severely degraded grassland than in the lightly degraded grassland.. Total carbon and nitrogen concentration was higher in the aboveground tissue than belowground roots. Total soil organic carbon concentration in severely degraded grassland was significantly lower than that in lightly degraded grassland, and decreased with depths. C and N content in unit area was soil depths 0-20 cm > belowground root > aboveground issue in the same grassland types. The total carbon content of unit area of aboveground tissue, roots and soil depths 0-40 cm（14669.2 g/m2）declined after degradation from lightly to severely degraded grassland（13554.3 g/m2） 7.60%, in which that of soil 0-40 cm declined 4.10%, that of belowground roots declined 59.97% and aboveground tissue declined 15.39%. The nitrogen content of unit area of aboveground tissue, roots and soil depths 0-40 cm（3352.7 g/m2）increased after degradation from lightly to severely degraded grassland（3780.6 g/m2）12.76%, in which that of soil 0-40 cm increased 13.07%, that of belowground roots declined 55.09% and aboveground tissue declined 16.00%. Thanks to degraded grassland, The total carbon lost 11149 kg/hm2, and total nitrogen increased 4278 kg/hm2.

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