西藏色季拉山北坡表层土壤有机碳垂直分布特征研究

Vertical Distribution Characteristics of Surface Soil Organic Carbon on the North Slope of Sygera Mountains,Tibet

为研究西藏色季拉山北坡表层土壤有机碳的垂直分布特征,于2017年8月,在不同海拔梯度布设2个30 m×30 m样地,样方内按S型布设5个样点后分别采集表层0~30 cm土样,研究了土壤有机碳垂直分布特征。结果表明:随着海拔的升高,土壤pH值呈降低的趋势,其变化范围为4.97~6.18。林芝云杉林的土壤pH值最高,为6.18,高山草甸的土壤pH值最低,为4.97。高山灌丛和高山草甸的土壤有机质和全氮含量丰富,达到了17.28 g/kg和0.88 g/kg,而林芝云杉林的土壤有机质和全氮和速效磷含量最低,分别为11.5 g/kg、0.70 g/kg和3.77 mg/kg,而高山灌丛的速效磷含量最高,为6.09 mg/kg。土壤总有机碳含量呈增加的趋势,林芝云杉林的土壤有机碳含量最低(5.223 mg/kg),高山草甸的土壤有机碳含量最高(12.867 mg/kg)。土壤颗粒有机碳、易氧化有机碳和可溶性有机碳含量变化特征与土壤有机碳含量变化趋势一致。不同海拔梯度土壤颗粒有机碳含量与土壤总有机碳含量、易氧化有机碳含量与土壤总有机碳含量均达到极显著相关水平,且土壤颗粒有机碳含量和易氧化有机碳含量之间也达到了极显著相关水平。土壤有机质对土壤有机碳的影响最大,其次为全氮,而全钾与土壤总有机碳含量呈负相关。

In order to study the distribution characteristics of surface soil organic carbon on the north slope of Sygera Mountains,we chose 7 plots at different altitudes in July 2017 and collect 0~30 cm sectional soil samples in 30 m×30 m sample of 2 plots to analysis the content of soil organic carbon.The results showed that the pH value of soil presented a decreasing trend with a range of 4.97~6.18 along the increase of altitude.Soil pH value of Picea likiangensis var.linzhiensis forest was the highest at 6.18 and that of Alpine meadow was the lowest at 4.97.Alpine scrub and Alpine meadow was rich in soil organic matter and total nitrogen reached 17.28 g/kg and 0.88 g/kg,while Picea likiangensis var.linzhiensis forest had the lowest content of soil organic matter and total nitrogen,which was 11.5 g/kg and 0.70 g/kg.The content of available phosphorus in Picea likiangensis var.linzhiensis forest was the lowest at 3.77 mg/kg,while that in Alpine meadow was the highest at 6.09 mg/kg.The situation of available potassium in soil was similar to that of available phosphorus.The total soil organic carbon content showed an increasing trend.The soil organic carbon content of Picea likiangensis var.linzhiensis forest was the lowest(5.223mg/kg)and that of Alpine meadow was the highest(12.867mg/kg).The variation characteristics of soil particulate organic carbon,easily oxidized organic carbon and soluble organic carbon content were consistent with the variation trend of soil organic carbon content.Soil particle organic carbon content and total organic carbon content,easily oxidized organic carbon content and soil total organic carbon content in different elevation gradients all reached the extremely significant correlation level,and the soil particle organic carbon content and easily oxidized organic carbon content also reached the extremely significant correlation level.Soil organic matter had the largest effect on soil organic carbon,which followed by total nitrogen,while total potassium was negatively correlated with total organic carbon content.