青藏高原东部不同草地类型土壤养分的分布规律

调查分析了青藏高原东部高寒草甸、高寒灌丛草甸、亚高寒草甸、沼泽化草甸、荒漠化草原、林间草地、盐渍化沼泽土壤碳氮磷含量垂直分布特征。结果表明，7种草地类型中，土壤有机碳含量大体随着土层的深入而降低，0~15 cm土层土壤有机碳的累积量从高到低依次为林间草地>高寒灌丛草甸>高寒草甸>沼泽化草甸>盐渍化沼泽>亚高寒草甸>荒漠化草甸(P<0.05)；随土层深度变化土壤全氮含量与有机碳相似，0～15 cm全氮累积量从高到低依次为沼泽化草甸>林间草地>高寒灌丛草甸>高寒草甸>盐渍化沼泽>荒漠化草原>亚高寒草甸(P<0.05)；荒漠化草原、林间草地和土壤全磷含量随土层深度无明显规律性，0～15 cm土层全磷累积量由高到低依次为高寒灌丛草甸>沼泽化草甸>高寒草甸>盐渍化沼泽>亚高寒草甸>荒漠化草原>林间草地(P<0.05)；随土层深度的增加不同草地类型养分含量顺序不同。除沼泽化草甸，不同草地类型下土壤有机碳与全氮呈显著正相关。

Distribution pattern of soil nutrients in different grassland types and soil depths in the eastern Tibetan Plateau

The vertical distributions of carbon,nitrogen and phosphorous in the soil profiles in 7 grassland types in the eastern Tibetan Plateau were investigated.These grassland types were: alpine meadow,alpine shrub meadow,sub-alpine meadow,swamp meadow,desertified steppe,interforest grassland and saline-alkaline meadow.Our results showed that soil organic carbon decreased with soil depth in the 7 different grassland types,and that the cumulative amount of soil organic carbon at 0-15 cm depth in the 7 types was decreased in the following order: interforest grassland>alpine shrub meadow>alpine meadow>swamp meadow>saline-alkaline meadow>sub-alpine meadow>desertified steppe(P<0.05).The dynamic of soil total nitrogen in soil depths was similar to that of soil organic carbon,and the cumulative amount of soil total nitrogen at 0-15 cm depth in the investigated types,from highest to lowest,was: swamp meadow>interforest grassland>alpine shrub meadow>testalpine meadow>swamp meadow>saline-alkaline meadow>desertified steppe>sub-alpine meadow(P<0.05).Soil total phosphorus showed no obvious pattern in the desertified steppe and interforest grassland types,and the cumulative amount of soil total phosphorus at 0-15 cm depth in the 7 types was decreased in the following order: alpine shrub meadow>swamp meadow>alpine meadow>saline-alkaline meadow>sub-alpine meadow>desertified steppe>interforest grassland(P<0.05).Soil nutrient distribution varies when soil depth increases in different grassland types.Soil organic carbon was significantly correlated with soil total nitrogen in all grassland types except the swamp meadow.