Effects of Nitrogen and Phosphorus Addition on Soil Carbon and Nitrogen Mineralization in Temperate Forest and Subtropical Forest

The soils collected from a temperate forest in Wuying in Heilongjiang Province and a subtropical forest in Wuyi Mountain in Fujian Province were used to investigate the effects of nitrogen and phosphorus addition (NH4NO3 and NaH2PO4) on soil carbon and net nitrogen mineralization in the topsoil (0–20 cm) through a 120-day laboratory incubation experiment. The results showed that nitrogen addition reduced soil carbon mineralization in the subtropical forest by reducing soil microbial biomass and its carbon/nitrogen ratio, but had no significant effect on soil carbon mineralization in the temperate forest. Phosphorus addition had no significant effect on soil carbon mineralization in the two forests. Moreover, phosphorus addition significantly increased soil net nitrogen mineralization in the temperate forest, nitrogen addition significantly reduced soil net nitrogen mineralization in the temperate forest, but nitrogen and phosphorus addition had no significant effect on soil net nitrogen mineralization in the subtropical forest. In general, the responses of soil carbon and net nitrogen mineralization to nitrogen and phosphorus addition are different between the temperate forest and the subtropical forest, likely due to the differences in nutrient availability and soil properties between the two forests. © 2022 Peking University. All rights reserved.