Phosphorus addition regulates the responses of soil multifunctionality to nitrogen over-fertilization in a temperate grassland

Aim Nitrogen (N) and phosphorus (P) are two major limiting factors in terrestrial ecosystems. Excessive N applications alter ecosystem functions by causing nutrient imbalances with P. Yet, little is known about why and how the balance between N and P regulates soil multifunctionality -the simultaneous provision of multiple soil functions-. Methods We explored how P additions regulated the responses of soil multifunctionality to different levels of N fertilization (10, 20, 40 g N m(-2) yr(-1)) using a mesocosm experiment in a temperate grassland in China. Results Nitrogen alone and P addition increased multifunctionality at rate of <= 10 and 20 g N m(-2) yr(-1), respectively. However, the magnitude of positive effects decreased with N additions over this level. P additions increased multifunctionality resistance to N at low rate of <= 10 g m(-2) yr(-1)compared to higher N levels. Soil N:P stoichiometry and plant diversity played dominant roles in regulating soil multifunctionality. Conclusions We found that a balanced combination of N and P additions (20:10) can help maintain the highest multifunctionality in this temperate grassland. The results provide new insights that through P addition, we could better manage soil multifunctionality and increase its resistance to expected fertilization scenarios (<= 10 g m(-2) yr(-1)).

Automated summary

Phosphorus addition can increase the responsiveness of soil multifunctionality to different levels of nitrogen fertilization, and enhance its resistance. Soil N:P stoichiometry and plant diversity play dominant roles in regulating soil multifunctionality.