Stoichiometric shifts in surface soils over broad geographical scales: evidence from China's grasslands

Yuanhe Yang*, Jingyun Fang, Chengjun Ji, Arindam Datta, Pin Li, Wenhong Ma, Anwar Mohammat, Haihua Shen, Huifeng Hu, Benjamin O. Knapp, Pete Smith

*Corresponding author for this work

Research output: Contribution to journalArticle

43 Citations (Scopus)

Abstract

Aim The identification of stoichiometric flexibility is crucial for understanding carbon-nitrogen-phosphorus (C-N-P) interactions and ecosystem dynamics under a changing environment. However, current evidence of stoichiometric flexibility mainly comes from manipulation experiments, with little evidence from large-scale observations.

Location Alpine and temperate grasslands across northern China.

Methods Using soil profiles derived from a historical national soil inventory and a contemporary regional soil survey across China's grasslands, we examined temporal changes in topsoil C:N:P ratios over recent decades.

Results Topsoil C: N ratios of five major grassland types exhibited some flexibility but did not show significant changes over the sampling interval. Non-significant changes in topsoil C: N ratios were observed both in alpine grasslands on the Tibetan Plateau and in temperate grasslands on the Inner Mongolian Plateau. Consistent with the relatively stable C: N ratios, the slope of the soil C-N stoichiometric relationship did not differ significantly between the two sampling periods. Soil N: P ratios in the surface layer increased significantly over the sampling interval, however, with an overall increase of 0.60 (95% confidence interval 0.58-0.62). A larger increase in soil N: P ratio was found in temperate grasslands on the Inner Mongolian Plateau than in alpine grasslands on the Tibetan Plateau. Moreover, the slope of the soil N-P stoichiometric relationship in these grassland ecosystems became steeper over the sampling interval.

Main conclusions These results demonstrate the stability of topsoil C: N stoichiometry but variability in N: P stoichiometry over broad geographical scales, highlighting that soil C and N are tightly coupled, but N and P tend to be decoupled under a changing environment.

Original languageEnglish
Pages (from-to)947-955
Number of pages9
JournalGlobal Ecology and Biogeography
Volume23
Issue number8
Early online date20 Apr 2014
DOIs
Publication statusPublished - Aug 2014

Keywords

  • carbon-nitrogen-phosphorus interactions
  • carbon:nitrogen:phosphorus ratio
  • ecological stoichiometry
  • grassland ecosystems
  • soil inventory
  • stoichiometric flexibility
  • terrestrial ecosystems
  • nitrogen deposition
  • elevated CO2
  • microbial biomass
  • inorganic carbon
  • global change
  • phosphorus
  • limitation
  • decomposition
  • patterns

Cite this

Yang, Y., Fang, J., Ji, C., Datta, A., Li, P., Ma, W., Mohammat, A., Shen, H., Hu, H., Knapp, B. O., & Smith, P. (2014). Stoichiometric shifts in surface soils over broad geographical scales: evidence from China's grasslands. Global Ecology and Biogeography, 23(8), 947-955. https://doi.org/10.1111/geb.12175