Stoichiometry Characteristics of C, N, and P of Soil Profiles along an Altitude Gradient in Luofu Mountain, Guangdong.

The vertical distribution and stoichiometry characteristics of soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP) of soil profiles along an altitude gradient were investigated in Luofu Mountain, Guangdong. A total of ten sites at different altitude gradients in Luofu Mountain were selected and soil genetic horizon samples were collected. Soil physic-chemical properties, such as bulk density, soil particle-size composition, pH, SOC, TN, TP, total iron oxides (Fet), free iron oxides (Fed), amorphous iron oxides(Feo), CEC, etc, were determined to analyze the correlation of SOC, TN, TP, C:N ratio, C:P ratio, N:P ratio with altitude gradients, physic-chemical properties. Our findings suggest that with the increase of soil depth, SOC, TN, TP, C:N ratio, C:P, and N:P in Luofu Mountain decreased, While with the increase of altitude, SOC, TN, TP, C:P, N:P increased, C:N ratio increased, and SOC, TN, TP highly significantly or significantly correlated with altitude. Pearson correlation analysis showed that SOC, TN, TP had highly significant positive correlations with silt, Feo, Feo:Fed, CEC. SOC and TN were highly significantly or significantly negatively correlated with clay, bulk density, Fet, Fed. TP had highly significant negative correlation with bulk density; C:N ratio, C:P ratio and N:P ratio showed highly significant positive correlation with CEC, while were highly significantly negatively correlated with bulk density, Fet, Fed. Redundancy analysis (RDA) showed that bulk density, clay, CEC, Fet, Feo and sand had highly significant effect on the stoichiometric characteristics of SOC, TN, TP, while altitude, pH, Fed, Fed:Fet ratio and Feo:Fed ratio had no significant effect. It was found that bulk density, clay, CEC, Fet and Feo are main soil physic-chemical factors that regulate the stoichiometric characteristics of SOC, TN, TP at different altitudes in the study area. [ABSTRACT FROM AUTHOR]