Impacts of nutrient addition on soil carbon and nitrogen stoichiometry and stability in globally-distributed grasslands

Katherine S. Rocci, Kaydee S. Barker, Eric W. Seabloom, Elizabeth T. Borer, Sarah E. Hobbie, Jonathan D. Bakker, Andrew S. MacDougall, Rebecca L. McCulley, Joslin L. Moore, Xavier Raynaud, Carly J. Stevens, M. Francesca Cotrufo

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


Global changes will modify future nutrient availability with implications for grassland biogeochemistry. Soil organic matter (SOM) is central to grasslands for both provision of nutrients and climate mitigation through carbon (C) storage. While we know that C and nitrogen (N) in SOM can be influenced by greater nutrient availability, we lack understanding of nutrient effects on C and N coupling and stability in soil. Different SOM fractions have different functional relevance and mean residence times, i.e., mineral-associated organic matter (MAOM) has a higher mean residence time than particulate organic matter (POM). By separating effects of nutrient supply on the different SOM fractions, we can better evaluate changes in soil C and N coupling and stability and associated mechanisms. To this end, we studied responses of C and N ratios and distributions across POM and MAOM to 6–10 years of N, phosphorus (P), potassium and micronutrients (K), and combined NPK additions at 11 grassland sites spanning 3 continents and globally relevant environmental gradients in climate, plant growth, soil texture, and nutrient availability. We found addition of N and NPK generally reduced C:N in MAOM and POM. However, at low fertility and at warm, sandy sites, nutrient addition promoted higher MAOM and POM C:N, respectively. Addition of NPK also promoted C storage in POM relative to MAOM, and this was consistent across sites. Our results suggest that addition of macro- and micronutrients consistently decrease SOM stabilization, whereas responses of soil C:N stoichiometry were contingent on SOM fraction and environmental conditions.

Original languageEnglish
Pages (from-to)353-370
Number of pages18
Issue number3
StatePublished - Jul 2022

Bibliographical note

Publisher Copyright:
© 2022, The Author(s), under exclusive licence to Springer Nature Switzerland AG.


  • Grasslands
  • Mineral-associated organic matter
  • Nitrogen
  • Nutrient addition
  • Nutrient network (NutNet)
  • Particulate organic matter
  • Phosphorous
  • Potassium
  • Soil organic matter

ASJC Scopus subject areas

  • Environmental Chemistry
  • Water Science and Technology
  • Earth-Surface Processes


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