青藏高原高寒草原生态系统土壤碳磷比的分布特征

利用67个样点数据,研究了青藏高原高寒草原土壤碳磷比的分布特征。结果表明,1)土壤碳磷比的平均值为24.45,变化幅度为1.05～177.69。在水平方向上,土壤碳磷比呈现出西北高东南低的总体态势和斑块状交错分布的格局,高值区主要集中在藏北高原腹地和喜马拉雅北麓湖盆区,不同草地型和不同自然地带土壤磷含量差异显著; 2)19个草地型不同土层(0～10 cm,10～20 cm,20～30 cm,30～40 cm)碳磷比的平均值分别为26.15,33.59,30.33和22.76,表土层(10～20 cm)与底土层(30～40 cm)碳磷比差异显著。土壤剖面自上而下,碳磷比可分为低－高－低－高型、低－高－低型、高－低－高－低型、高－低－高型和由高到低型等5个类型; 3)土壤碳磷比与植被盖度、植被高度、20～30 cm土壤容重、10～20 cm土壤含水量、30～40 cm土壤含水量、HCO₃^-含量呈显著正相关关系,而与≥10℃年积温、年均相对湿度、10～20 cm地下生物量、0～10 cm土壤容重、0～10 cm土壤含水量、速效钾、有机质、总有机碳、水解性碳含量呈显著负相关关系。

Soil C/P distribution characteristics of alpine steppe ecosystems in the Qinhai-Tibetan Plateau

Soil C/P distribution characteristics of alpine steppe ecosystems in the Qinghai-Tibetan Plateau were researched based on data measured at 67 sampling points. 1) The average C/P was 24.45 with variances of 1.05-177.69 In a horizontal direction. It appeared higher in the northwest and lower in the southeast as a macrocosm tendency with distribution characteristics of a staggered pattern. The higher C/P levels appeared mainly in the regions concentrated in the hinterland of the northern parts of the Tibetan Plateau and in the lake basin region at the northern foot of the Himalayas. There were significant differences of C/P among different grass-types and natural transects. 2) The average C/P ratio at different soil depths (0-10 cm, 10-20 cm, 20-30 cm and 30-40 cm) among 19 grassland types were 26.15, 33.59, 30.33 and 22.76, respectively. In a vertical direction, soil depths from aboveground to underground, could be divided into 5 types of C/P distribution patterns (low-high-low-high, low-high-low, high-low-high-low, high-low-high, and high-low) among different grass types. 3) C/P was significantly positively correlated with vegetation coverage, vegetation height, and soil bulk density at depths from 20 to 30 cm, soil water content at depths from 10 to 20 cm, and at depths from 30 to 40 cm and with soil content of HCO₃^-. The C/P ratio was significantly correlated with ≥10℃ accumulated temperature, and with the average annual relative humidity, the underground biomass at soil depths from 10 to 20 cm, soil bulk density at depths from 0 to 10 cm, soil water content at depths from 0 to 10 cm. It was negatively correlated with soil content of available K, organic matter, total organic carbon and hydrolysable carbon.