Pedosphere 30(1): 87--97, 2020
ISSN 1002-0160/CN 32-1315/P
©2020 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Evidence for niche differentiation of nitrifying communities in grassland soils after 44 years of different field fertilization scenarios |
Zhongjun JIA1 , Xue ZHOU2, Weiwei XIA1,3, Dario FORNARA4, Baozhan WANG1, Elizabeth Anne WASSON4, Peter CHRISTIE4, Martin F. POLZ5, David D. MYROLD6 |
1State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008(China);
2State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing 210098(China);
3Jiangsu Key Laboratory of Agricultural Meteorology, College of Applied Meteorology, Nanjing University of Information Science and Technology, Nanjing 210044(China);
4Agri-Food and Biosciences Institute, Belfast BT9 5PX(UK);
5Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge MA 02139(USA);
6Department of Crop and Soil Science, Oregon State University, Corvallis OR 97331(USA) |
| Corresponding Author:Zhongjun JIA |
| ABSTRACT |
| Long-term nitrogen (N) fertilization imposes strong selection on nitrifying communities in agricultural soil, but how a progressively changing niche affects potentially active nitrifiers in the field remains poorly understood. Using a 44-year grassland fertilization experiment, we investigated community shifts of active nitrifiers by DNA-based stable isotope probing (SIP) of field soils that received no fertilization (CK), high levels of organic cattle manure (HC), and chemical N fertilization (CF). Incubation of DNA-SIP microcosms showed significant nitrification activities in CF and HC soils, whereas no activity occurred in CK soils. The 44 years of inorganic N fertilization selected only 13C-ammonia-oxidizing bacteria (AOB), whereas cattle slurry applications created a niche in which both ammonia-oxidizing archaea (AOA) and AOB could be actively 13C-labeled. Phylogenetic analysis indicated that Nitrosospira sp. 62-like AOB dominated inorganically fertilized CF soils, while Nitrosospira sp. 41-like AOB were abundant in organically fertilized HC soils. The 13C-AOA in HC soils were affiliated with the 29i4 lineage. The 13C-nitrite-oxidizing bacteria (NOB) were dominated by both Nitrospira-and Nitrobacter-like communities in CF soils, and the latter was overwhelmingly abundant in HC soils. The 13C-labeled nitrifying communities in SIP microcosms of CF and HC soils were largely similar to those predominant under field conditions. These results provide direct evidence for a strong selection of distinctly active nitrifiers after 44 years of different fertilization regimes in the field. Our findings imply that niche differentiation of nitrifying communities could be assessed as a net result of microbial adaption over 44 years to inorganic and organic N fertilization in the field, where distinct nitrifiers have been shaped by intensified anthropogenic N input. |
| Key Words: ammonia-oxidizing archaea,ammonia-oxidizing bacteria,community shift,long-term fertilization,nitrite-oxidizing bacteria,nitrogen enrichment,stable isotope probing microcosm |
| Citation: Jia Z J, Zhou X, Xia W W, Fornara D, Wang B Z, Wasson E A, Christie P, Polz M F, Myrold D D. 2020. Evidence for niche differentiation of nitrifying communities in grassland soils after 44 years of different field fertilization scenarios. Pedosphere. 30(1):87-97. |
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