Articles | Volume 12, issue 3
https://doi.org/10.5194/bg-12-757-2015
https://doi.org/10.5194/bg-12-757-2015
Research article
 | 
09 Feb 2015
Research article |  | 09 Feb 2015

Strong stoichiometric resilience after litter manipulation experiments; a case study in a Chinese grassland

C. Xiao, I. A. Janssens, Y. Zhou, J. Su, Y. Liang, and B. Guenet

Abstract. Global climate change has generally modified net primary production (NPP) which leads to increasing litter inputs in some ecosystems. Therefore, assessing the impacts of increasing litter inputs on soil nutrients, plant growth and ecological carbon (C) : nitrogen (N) : phosphorus (P) stoichiometry is critical for an understanding of C, N and P cycling and their feedback processes to climate change. In this study, we added plant above-ground litter, harvested near the experimental plots, to the 10–20 cm subsoil layer of a steppe community at rates equivalent to annual litter input of 0, 15, 30, 60 and 120%, respectively, covering the entire range of the expected NPP increases in this region due to climate change (10–60%). We measured the resulting C, N and P content of different pools (above- and below-ground plant biomass, litter, microbial biomass). Small litter additions, which are more plausible compared to the expected increase predicted by Earth system models, had no effect on the variables examined. Nevertheless, high litter addition (120% of the annual litter inputs) significantly increased soil inorganic N and available P, above-ground biomass, below-ground biomass and litter. Our results suggest that while very high litter addition can strongly affect C : N : P stoichiometry, the grassland studied here is resilient to more plausible inputs in terms of stoichiometric functioning.

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Short summary
Global climate change may increase the litter inputs in some ecosystems impacting the soil–plant system functioning. We added litter, to the 10–20 cm subsoil layer of a steppe community at different rates. Small litter additions had no effect on the stoichiometry, whereas the highest additions (not realistic compared to the future predictions) modified the system slightly. It suggests that the grassland studied here is resilient to more plausible inputs in terms of stoichiometric functioning.
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