马衔山不同海拔土壤碳、氮、磷含量及生态化学计量特征

研究半干旱地区土壤碳、氮、磷化学计量特征,了解其空间变化规律,有助于揭示半干旱地区C、N、P循环对全球气候变化的响应。本研究以半干旱区的马衔山为对象,选择5个海拔的7个样地,采集0~15、15~30 cm层的土壤,测定其有机碳(SOC)、全氮(TN)、全磷(TP)、pH、含水率等理化性质,分析其SOC、TN、TP化学计量与土壤理化因子之间的关系。结果表明:(1)0~15 cm土壤SOC、TN、TP含量高于15~30 cm土壤。表层土壤SOC、TN含量随海拔升高呈增加趋势,TP含量随海拔升高变化较小。(2)C∶N随海拔增加呈先增加后降低趋势,C∶P、N∶P随海拔升高均呈增加趋势。(3)在0~15 cm土壤中,pH与SOC、TN含量及C∶P呈显著负相关,在15~30 cm土层中,pH与SOC、TN、TP含量及化学计量特征关系不显著;土壤含水率与0~15、15~30 cm层土壤中SOC、TN含量均呈极显著正相关。本研究显示,在半干旱区的马衔山地区,土壤含水率随海拔增加而增加,而SOC、TN含量及C∶P、N∶P也呈增加趋势,土壤养分含量及化学计量均受土壤含水率影响。

Elevational distribution of soil organic carbon,nitrogen and phosphorus contents and their ecological stoichiometry on Maxian Mountain.

The stoichiometric characteristics and spatial patterns of soil organic carbon(SOC),total nitrogen(TN)and total phosphorus(TP)are useful indicators for understanding their responses to global climate change in semi-arid areas.In this study,we collected 0-15 cm and15-30 cm soil samples from seven plots at five altitudes in Maxian Mountain,which is located in the semi-arid area,to determine the physicochemical properties of SOC,TN,TP,pH and soil moisture content.The relationships among soil SOC,TN,TP stoichiometry and soil physical and chemical factors were examined.The results showed that:(1)The contents of SOC,TN,TP in the 0-15 cm soil layer were higher than those in 15-30 cm layer.The SOC and TN contents in the top soils increased with elevation,while the TP content did not change.(2)The C∶N ratios first increased and then decreased,while C∶P and N∶P ratios increased with elevation.(3)Soil pH was significantly negatively correlated with SOC,TN content and C∶P ratio in the 0-15 cm soil layer.In the 15-30 cm soil layer,soil p H had no relationship with SOC,TN,TP contents and their stoichiometric characteristics.Soil moisture content was significantly positively correlated with SOC and TN contents both in 0-15 cm and 15-30 cm soil layers.Soil moistureincreased with elevation,coinciding with the increases of SOC,TN contents and C∶P,N∶P ratios.Taken together,our results indicated that soil nutrient contents and stoichiometry in the study area were mainly influenced by soil moisture.