Exogenous nitrogen addition creates global thresholds for soil carbon stocks

Nitrogen (N) addition poses a major threat to biological diversity and functions, including to alter soil C stocks and challenge climate security. Yet, whether the response of soil C stocks to N addition follows a non-linear pattern driven by N thresholds remains an open question. Here, using a global synthesis on bulk soil organic C, particulate (POC) and mineral associated organic carbon (MAOC) stocks we found that N addition rate and duration both shape soil C cycling via global thresholdswithin the global N cycle.