Carbon (C) sequestration in terrestrial ecosystems largely depends on nitrogen (N) availability in response to rising atmospheric CO2, which would result in progressive N limitation (PNL) that C and N are simultaneously fixed in long-lived plant biomass and soil organic matter. Hence, it is critical to examine how N processes respond to elevated CO2 to alleviate PNL. Here we evaluated the central tendencies of the responses of several variables associated with ecosystem N cycle to elevated CO2, using data extracted from peer-reviewed papers.
Results/Conclusions
Our results showed that elevated CO2 induced uptake of inorganic N, hence reduce inorganic nitrogen leaching by around 20% under elevated CO2. N addition may trigger this effect, which results in a 40% reduction under elevated CO2 compared with ambient CO2. However, only N addition increased inorganic nitrogen leaching by 150%. Elevated CO2 also affected N mineralization, N2O flux, nitrification, and denitrification. Our results indicate that elevated CO2 may alleviate PNL through reduce leaching pathway.