Nitrification is the biological oxidation of NH3 to NO2 − and NO3 − for which ammonia-oxidizing bacteria (AOB) are the functionally dominant group in cropland responsible for the rate-limiting step of NH3 oxidation. Different AOB species have functional differentiation and do not equally contribute to nitrification. This investigation explored if long-term N fertilization and tillage influenced AOB community structure. The study site was a long-term (>40 years) continuous maize (Zea mays L.) experiment with three N fertilization rates (0, 168, and 336 kg ha−1) and either no-tillage (NT) or moldboard plow tillage (PT). We used denaturing gradient gel electrophoresis (DGGE) to analyze PCR-amplified bacterial ammonia monooxygenase genes and detect changes among NH3-oxidizing bacteria. Tillage, fertilization, and sample season all significantly influenced the AOB community. The AOB were more diverse in NT than PT. The AOB became more diverse with increasing N input and were more diverse in summer than winter samples. Nitrosomonas-like and Nitrosospira-like groups were identified based on gel migration patterns. Unique bands occurred in different treatments, manifesting environmental selection. The long-term field trial showed soil management consistently influenced AOB communities. Significantly, AOB diversity differed at a small scale within a relatively uniform landscape, even in the presence of long-term management practices.
|Number of pages||9|
|Journal||Applied Soil Ecology|
|State||Published - Aug 2018|
Bibliographical noteFunding Information:
The investigation reported in this paper (16-06-051) is in connection with a project of the Kentucky Agricultural Experiment Station and is published with the approval of the Director. Mention of trade names is for information only and does not imply endorsement by the Kentucky Agricultural Experiment Station. S. Liu was assisted by research and fellowship support from the Department of Plant and Soil Sciences and a College of Agriculture, Food, and Environment Research Activities Award (University of Kentucky). The technical support of Ann Freytag and Gloria Gellin are greatly appreciated as are the analytical facilities of the USDA-FAPRU unit. Appendix A
© 2018 Elsevier B.V.
- Ammonia oxidizing bacteria
- Autotrophic nitrification
- Community structure
ASJC Scopus subject areas
- Agricultural and Biological Sciences (miscellaneous)
- Soil Science