Effects of simulated drought and phosphorus addition on nitrogen mineralization in tropical lowland rain forests

Aims Soil nitrogen (N) mineralization is the main process of N transformation, which determines soil N supply capacity. According to the report that the intensity and frequency of extreme hydrological events such as drought would continue to increase in the future. However, how drought impact on soil N mineralization in tropical lowland rain forests, and if this process is regulated by phosphorus (P) are less understood, given that tropical ecosystem is normally considered as P-limited. Methods Here, we employed a two-factor climate change manipulative experiment (50% throughfall reduction and P addition), which was established in 2019 in a tropical lowland rain forest in the Ganza Ridge Nature Reserve in Sanya, Hainan. The in-situ resin core method was used to study the effects of drought and P addition on soil inorganic N and N mineralization process. Important findings Our results show that: 1) Rainfall reduction significantly reduced the soil moisture at depths of 5 cm and 15 cm, but had no significant effect on soil temperature. 2) Rainfall reduction and the interactive