Soil C:N:P stoichiometry at different altitudes in Mao'er Mountain, Guangxi, China.

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.