We explored vertical distribution of soil organic carbon (C), nitrogen (N) and phosphorus (P) for examining the relationship between soil C:N:P stoichiometry and both altitudes and soil depths in Mao'er Mountain in Guangxi, South China. A total of ten sites from different altitudes were selected and soil genetic horizon samples were collected along soil profiles at each site. Soil organic C, N, P, pH, bulk density and particle size composition were measured. Results showed that soil C, N, C/P ratio and N/P ratio increased with the increases of altitude. Soil P concentrations and C/N ratio increased within low altitudes then decreased or with no obvious changes. Soil C, N, P, C/P and N/P ratios significantly decreased, whereas C/N ratio did not change with the increases of soil depth. Soil C and N highly coupled within horizons (CV of C/N was 4.0%) and soil P had little spatial variability (CV were 31.0% and 22.0% within altitudes and horizons, respectively). The results from redundancy analysis showed that the first two axes explained 74.8% of the variability of C:N:P stoichiometry. Soil pH, bulk density, and altitude had significant effects on C:N:P stoichiometry, whereas clay, silt, and sand had no effect.
为探究我国华南地区山地土壤有机碳(C)、氮(N)、磷(P)含量垂直分布特征,阐明土壤C、N、P生态化学计量特征对海拔和土层深度的响应,以广西猫儿山为研究对象,选取不同海拔的10个地点,采集了不同发生层的土壤,测定有机C、N、P、pH、容重和机械组成等土壤性质,探讨了不同海拔及深度土壤C、N、P生态化学计量特征及其影响因素.结果表明: 随着海拔升高,土壤C、N、C/P、N/P均呈增加趋势,土壤P呈先增后降趋势,C/N则呈先增后保持平稳趋势;随着土壤深度增加,土壤C、N、P、C/P、N/P均呈显著降低趋势,C/N无显著变化,C、N在不同发生层土壤间具有较高的耦合性(C/N变异系数为4.0%);土壤P在空间上的变异较小(不同海拔、发生层间变异系数分别为31.0%和22.0%).冗余分析结果显示,前2个排序轴反映了土壤C、N、P化学计量特征变异信息量的74.8%,土壤pH、容重和海拔对土壤C、N、P化学计量特征有显著影响,而黏粒、粉粒和砂粒影响效果不显著.
Keywords: C, N and P; Mao'er Mountain; altitude; redundancy analysis; stoichiometry characteristics.