Conclusion
With a combination of a field experiment, a meta-analysis, and an
empirical modeling approach we found that the substrate competition
theory is most likely the predominant mechanism explaining the P
alleviation of the N-suppression of CH4 uptake, and we
further estimated that contemporary atmospheric N deposition suppresses
the CH4 sink in global grasslands by 11.4% while P
deposition alleviates this suppression by 5.8%.
This study is among the first attempts to quantify the P impacts on the
N suppression of soil oxidation of atmospheric CH4 in
global grasslands. It advocates model development to incorporate P
mechanisms not only for the nutrient impacts on carbon cycling, but also
for a more accurate projection of the CH4 budget of
terrestrial ecosystems.