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Urea fertilization and grass species alter microbial nitrogen cycling capacity and activity in a C4 native grassland.
- Source :
- PeerJ; Aug2022, p1-20, 20p
- Publication Year :
- 2022
-
Abstract
- Soil microbial transformation of nitrogen (N) in nutrient-limited native C<subscript>4</subscript> grasslands can be affected by N fertilization rate and C<subscript>4</subscript> grass species. Here, we report in situ dynamics of the population size (gene copy abundances) and activity (transcript copy abundances) of five functional genes involved in soil N cycling (nifH, bacterial amoA, nirK, nirS, and nosZ) in a field experiment with two C<subscript>4</subscript> grass species (switchgrass (Panicum virgatum) and big bluestem (Andropogon gerardii)) under three N fertilization rates (0, 67, and 202 kg N ha<superscript>-1</superscript>). Diazotroph (nifH) abundance and activity were not affected by N fertilization rate nor grass species. However, moderate and high N fertilization promoted population size and activity of ammonia oxidizing bacteria (AOB, quantified via amoA genes and transcripts) and nitrification potential. Moderate N fertilization increased abundances of nitrite-reducing bacterial genes (nirK and nirS) under switchgrass but decreased these genes under big bluestem. The activity of nitrous oxide reducing bacteria (nosZ transcripts) was also promoted by moderate N fertilization. In general, high N fertilization had a negative effect on N-cycling populations compared to moderate N addition. Compared to big bluestem, the soils planted with switchgrass had a greater population size of AOB and nitrite reducers. The significant interaction effects of sampling season, grass species, and N fertilization rate on N-cycling microbial community at genetic-level rather than transcriptional-level suggested the activity of N-cycling microbial communities may be driven by more complex environmental factors in native C<subscript>4</subscript> grass systems, such as climatic and edaphic factors. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 21678359
- Database :
- Complementary Index
- Journal :
- PeerJ
- Publication Type :
- Academic Journal
- Accession number :
- 160517536
- Full Text :
- https://doi.org/10.7717/peerj.13874