Pedosphere 29(4): 492--503, 2019
ISSN 1002-0160/CN 32-1315/P
©2019 Soil Science Society of China
Published by Elsevier B.V. and Science Press
Responses of Soil Microbial Community Structure and Activity to Incorporation of Straws and Straw Biochars and Their Effects on Soil Respiration and Soil Organic Carbon Turnover
TIAN Xiaoping1,2, WANG Lei1,2, HOU Yahong1,2, WANG Han1,2, TSANG Yiu Fai3, WU Jihua4
1Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092(China)
2Research Institution for Shanghai Pollution Control and Ecological Security, Shanghai 200092(China)
3Department of Science and Environmental Studies, The Education University of Hong Kong, Hong Kong 999077(China)
4Ministry of Education, Key Laboratory for Biodiverstiy Science and Ecological Engineering, School of Life Sciences, Fudan University, Shanghai 200433(China)
ABSTRACT
      Like straw, biochar incorporation can influence soil microorganisms and enzyme activities and soil carbon (C) responses; however, few studies have compared the various effects of straw and biochar and the underlying mechanisms. An experiment was performed to study the changes in soil respiration (SR) and soil organic C (SOC) fluxes in response to the incorporation of three kinds of straw (reed, smooth cordgrass, and rice) and their pyrolyzed products (biochars) at Chongming Island, China. In addition, the microbial activity and community structure of some amended soils were also analyzed to clarify the mechanisms of these responses. The results showed that all biochar incorporation (BC) induced lower SR than the corresponding unpyrolyzed straw incorporation (ST), and the average SR in the soils following BC and ST during the experimental periods was 21.69 and 65.32 μmol CO2 m-2 s-1, respectively. Furthermore, the average SOC content was 16.97 g kg-1 following BC, which was higher than that (13.71 g kg-1) following ST, indicating that compared to ST, BC was a low-C strategy, even after accounting for the C loss during biochar production. Among the BC treatments, reed-BC induced the lowest SR (17.04 μmol CO2 m-2 s-1), whereas smooth cordgrass-BC induced the highest SR (27.02 μmol CO2 m-2 s-1). Furthermore, in contrast with ST, BC significantly increased the abundance of some bacteria with poorer mineralization or better humification ability, which led to lower SR. The lower easily oxidizable C (EOC) and higher total C contents of biochars induced lower SR and higher SOC in the soil following BC compared to that following ST. Among the BC treatments, the higher total nitrogen content of rice biochar led to significantly higher soil microbial biomass, and the lower EOC content of reed biochar led to lower soil microbial activity and SR.
Key Words:  easily oxidizable carbon,soil fertility,soil microbial abundance,soil microbial biomass,soil microbial diversity,soil organic carbon decomposition
Citation: Tian X P, Wang L, Hou Y H, Wang H, Tsang Y F, Wu J H. 2019. Responses of soil microbial community structure and activity to incorporation of straws and straw biochars and their effects on soil respiration and soil organic carbon turnover. Pedosphere. 29(4):492-503.
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