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Does the accelerated soil N cycling sustain N demand of Quercus mongolica after decade-long elevated CO2 treatment?
- Source :
-
Biogeochemistry . Jul2018, Vol. 139 Issue 2, p197-213. 17p. - Publication Year :
- 2018
-
Abstract
- The stimulation of plant growth and biomass accumulation by elevated CO2 may be limited by soil nitrogen (N) availability. However, our understanding of the response of soil N cycling to elevated CO2 and when progressive N limitation occurs remains limited. Here, we used an open top chamber experiment to examine the effects of 10 years of elevated CO2 on ecosystem carbon (C) and N dynamics in a Quercus mongolica (oak) dominated system in northeastern China. Elevated CO2 increased oak biomass, C and N stocks and C/N by 26.4, 26.2, 16.5 and 8.6% respectively, which suggests increased plant N demand. Soil gross N mineralization, re-mineralization of microbial N and nitrification were accelerated likely due to increased photosynthesis (by 34.9%) and microbial biomass (by 24.2%) under elevated CO2. Thus, the supply of soil available N can sustain the tree growth stimulated by elevated CO2, and to date progressive N limitation has not happened. Nevertheless, both the annual increase of oak biomass, C and N stocks and C/N ratio and the seasonal variations of soil available N and microbial N concentrations, and net N transformation rates indicated that gradual N deficiency may be occurring and the CO2 fertilization effect has weakened with increasing treatment duration. [ABSTRACT FROM AUTHOR]
- Subjects :
- *PLANT growth
*PLANT biomass
*NITROGEN in soils
*CARBON dioxide
*BIOAVAILABILITY
Subjects
Details
- Language :
- English
- ISSN :
- 01682563
- Volume :
- 139
- Issue :
- 2
- Database :
- Academic Search Index
- Journal :
- Biogeochemistry
- Publication Type :
- Academic Journal
- Accession number :
- 130276048
- Full Text :
- https://doi.org/10.1007/s10533-018-0463-9