Litter removal harms long-term nutrient dynamics in tropical secondary forest

Aims A project developed over eight years in the Amazonia manipulated water availability through periodic irrigation (IRR) and nutrients through biweekly litter removal (REM). This study aimed to investigate whether, after 16 years of resource management (water and nutrients), the effects on litter and soil nutrient dynamics are still observable, initially hypothesizing that differences would be evident and that water supply would result in improved soil conditions in the forest. Methods We evaluated the chemical properties of soil and litter in a secondary forest in the eastern Amazonia, calculating the nutrient use efficiency (NUE) and nutrient retranslocation rate. Results The results showed that resource manipulation had residual effects on the dynamics of K, Ca, Mg, and P nutrients. IRR increased soil K availability, while REM reduced pH and monthly production of Ca, Mg, and P. Additionally, it was found that the NUE of Ca and Mg could be impaired with increased rainfall, while higher temperatures provided greater N and P NUE, reinforcing global warnings about the impacts of climate change. Conclusions In summary, the results provide important insights for the management of secondary forests and suggest that resource management may have a long-term impact on nutrient dynamics in secondary forests.