Soil acidification alters C : N : P stoichiometry in the soil due to higher acid sensitivity of phosphorus

< 0.05), with the pH 2.0 treatment inducing a decline in soil pH ranging from 12.43% to 32.22% in the five soils. However, soil acidification did not significantly change soil organic C content, except in the cases of the strong acidification treatment in lateritic red soil and limestone soil, whereas it significantly or marginally significantly increased soil total N content in the five soils. Across the five soils or in each soil, the acidification treatments consistently and significantly linearly reduced soil total P content, with the pH 2.0 treatment resulting in soil total P reduction by 32.90%, 21.78%, 27.82%, 25.93% and 30.67% in acid sulfate soil, red soil, lateritic red soil, latosol and limestone soil, respectively. Correspondingly, soil available P content significantly increased under acidification treatments. Such asymmetrical responses of soil C, N and P contents resulted in significant alterations in soil C : N : P stoichiometry under acidification scenarios, with soil C : P and N : P ratios increased significantly. These results suggest that soil acidification may increase soil C : P and N : P ratios mainly by decreasing soil total P content, due to the activation of soil P as available P components.