Ecological stoichiometry and environmental influencing factors of soil nutrients in the karst rocky desertification ecosystem, southwest China

The stoichiometry characteristics and environmental influencing factors of soil nutrients of the three typical karst rocky desertification sites in Southwest China were studied. The results showed that the average contents of soil C, N, P and K in the three typical rocky desertification sites were 45.61, 2.54, 0.79 and 3.33 g/kg, respectively. The average values of C:N, C:P, C:K, N:P, N:K and P:K were 19.56, 65.07, 23.65, 3.45, 1.32 and 0.39, respectively. The variation of soil element K was significantly higher than that of the others. There were significant differences in the soil nutrient contents or stoichiometric ratios among the different sampling sites, rocky desertification degrees, or vegetation cover ratios. There were significant nonlinear correlations among soil nutrient contents. And there were also significant nonlinear correlations between soil nutrient contents and their stoichiometric ratios. Precipitation, temperature, rock outcrops, and land cover were the main environmental influencing factors for the stoichiometric characteristics of soil nutrients in the karst rocky desertification ecosystem. Results of the present study have important significance for the theory improvement of soil ecological stoichiometry and the scientific rehabilitation and control of the karst rocky desertification in Southwest China.