Editor: Ian Wright
Stoichiometric shifts in surface soils over broad geographical scales: evidence from China's grasslands
Article first published online: 20 APR 2014
© 2014 John Wiley & Sons Ltd
Global Ecology and Biogeography
Volume 23, Issue 8, pages 947–955, August 2014
How to Cite
Yang, Y., Fang, J., Ji, C., Datta, A., Li, P., Ma, W., Mohammat, A., Shen, H., Hu, H., Knapp, B. O. and Smith, P. (2014), Stoichiometric shifts in surface soils over broad geographical scales: evidence from China's grasslands. Global Ecology and Biogeography, 23: 947–955. doi: 10.1111/geb.12175
- Issue published online: 4 JUL 2014
- Article first published online: 20 APR 2014
- National Basic Research Program of China on Global Change. Grant Numbers: 2014CB954001, 2010CB950600
- National Natural Science Foundation of China. Grant Numbers: 31322011, 41371213, 31021001
- Carbon–nitrogen–phosphorus interactions;
- carbon:nitrogen:phosphorus ratio;
- ecological stoichiometry;
- grassland ecosystems;
- soil inventory;
- stoichiometric flexibility
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.
Alpine and temperate grasslands across northern China.
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.
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.
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.