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Sci Total Environ. 2016 Nov 15;571:615-23. doi: 10.1016/j.scitotenv.2016.07.029. Epub 2016 Jul 9.

Variations in the patterns of soil organic carbon mineralization and microbial communities in response to exogenous application of rice straw and calcium carbonate.

Author information

1
Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, PR China; University of Chinese Academy of Sciences, Beijing 100039, PR China; Huanjiang Observation and Research Station for Karst Ecosystems, Chinese Academy of Sciences, Huangjiang 547100, PR China.
2
Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, PR China; University of Chinese Academy of Sciences, Beijing 100039, PR China; Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, PR China.
3
Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, PR China; College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha 410128, PR China.
4
Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, PR China; Huanjiang Observation and Research Station for Karst Ecosystems, Chinese Academy of Sciences, Huangjiang 547100, PR China.
5
Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, PR China.
6
Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, PR China; Huanjiang Observation and Research Station for Karst Ecosystems, Chinese Academy of Sciences, Huangjiang 547100, PR China. Electronic address: hbhpjhn@isa.ac.cn.

Abstract

The addition of exogenous inorganic carbon (CaCO3) and organic carbon has an important influence on soil organic carbon (SOC) mineralization in karst soil, but the microbial mechanisms underlying the SOC priming effect are poorly understood. We conducted a 100-day incubation experiment involving four treatments of the calcareous soil in southwestern China's karst region: control, (14)C-labeled rice straw addition, (14)C-labeled CaCO3 addition, and a combination of (14)C-labeled rice straw and CaCO3. Changes in soil microbial communities were characterized using denaturing gradient gel electrophoresis with polymerase chain reaction (PCR-DGGE) and real-time quantitative PCR (q-PCR). Both (14)C-rice straw and Ca(14)CO3 addition stimulated SOC mineralization, suggesting that organic and inorganic C affected SOC stability. Addition of straw alone had no significant effect on bacterial diversity; however, when the straw was added in combination with calcium carbonate, it had an inhibitory effect on bacterial and fungal diversity. At the beginning of the experimental period, exogenous additives increased bacterial abundance, although at the end of the 100-day incubation bacterial community abundance had gradually declined. Incubation time, exogenous input, and their interaction significantly affected SOC mineralization (in terms of priming and the cumulative amount of mineralization), microbial biomass carbon (MBC), and microbial community abundance and diversity. Moreover, the key factors influencing SOC mineralization were MBC, bacterial diversity, and soil pH. Overall, these findings support the view that inorganic C is involved in soil C turnover with the participation of soil microbial communities, promoting soil C cycling in the karst region.

KEYWORDS:

Isotope tracing technique; Karst; PCR-DGGE; Priming effect; Soil microbial communities; Soil organic carbon mineralization

PMID:
27401276
DOI:
10.1016/j.scitotenv.2016.07.029
[Indexed for MEDLINE]

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