Journal
SCIENCE OF THE TOTAL ENVIRONMENT
Volume 743, Issue -, Pages -Publisher
ELSEVIER
DOI: 10.1016/j.scitotenv.2020.140808
Keywords
Root exudates; Paddy soil ecosystem; Nutrient stoichiometry; Priming effects; Microbial C-use efficiency
Categories
Funding
- National Key Research and Development program [2016YFE0101100]
- National Science Foundation of China [41877104]
- National Key Research and Development Programs of China [2018YFC0213300, 2017YFD0301505]
- Natural Science Foundation of Hunan Province [2019JJ30028]
Ask authors/readers for more resources
In paddy soil, the root exudates strongly influence the microbial activity and soil organic matter (SOM) mineralisation. However, the stoichiometric regulation of the mineralisation of root exudates and their priming effect on paddy soil remains unclear. Thus, we used manipulative laboratory incubations to measure the mineralisation of root exudates and the subsequent priming effect in paddy soil under different stoichiometric conditions. In this study, root exudates (simulated by C-13-labelled glucose, alanine, and oxalic acid) were added to the paddy soil along with four different amounts of N and P. The addition of simulated root exudates (SREs) enhanced the total CO2 and CH4 emissions. The mineralisation of SREs decreased by 20-45% after the addition of N and P when compared with exdusive SREs application. The addition of N and P inhibited the SREs-derived CH4 emissions when compared with SREs application alone. The mineralisation of soil organic matter (SOM) increased with SREs application, thereby generating a positive priming effect for CO2 and CH4 emissions. However, the priming effect for CO2 and CH4 emissions was reduced with increased amounts of N and P. Furthermore, the addition of SREs with increasing N and P significantly enhanced the microbial SREs-derived C-use efficiency. Structural equation models indicated that NH4+-N and Olsen P negatively influenced the priming effect, whereas the microbial biomass and enzyme stoichiometry positively influenced the priming effect. In conclusion, our data suggest that SREs combined with increasing amounts of N and P could meet microbial stoichiometric demands and regulate microbial activity, which finally inhibited the mineralisation of SREs-Card the priming effect on paddy soil and positively affected C sequestration. (C) 2020 Elsevier B.V. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available