Ammonia-oxidizing bacterial communities are affected by nitrogen fertilization and grass species in native C4 grassland soils

Jialin Hu; Jonathan D Richwine; Patrick D Keyser; Lidong Li; Fei Yao; Sindhu Jagadamma; Jennifer M DeBruyn

doi:10.7717/peerj.12592

Ammonia-oxidizing bacterial communities are affected by nitrogen fertilization and grass species in native C₄ grassland soils

PeerJ. 2021 Dec 16:9:e12592. doi: 10.7717/peerj.12592. eCollection 2021.

Authors

Jialin Hu¹, Jonathan D Richwine², Patrick D Keyser², Lidong Li³, Fei Yao¹, Sindhu Jagadamma¹, Jennifer M DeBruyn¹

Affiliations

¹ Department of Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, TN, United States of America.
² Department of Forestry, Wildlife and Fisheries, University of Tennessee, Knoxville, TN, United States of America.
³ Agroecosystem Management Research Unit, USDA-Agricultural Research Service, Lincoln, NE, United States of America.

Abstract

Background: Fertilizer addition can contribute to nitrogen (N) losses from soil by affecting microbial populations responsible for nitrification. However, the effects of N fertilization on ammonia oxidizing bacteria under C₄ perennial grasses in nutrient-poor grasslands are not well studied.

Methods: In this study, a field experiment was used to assess the effects of N fertilization rate (0, 67, and 202 kg N ha^-1) and grass species (switchgrass (Panicum virgatum) and big bluestem (Andropogon gerardii)) on ammonia-oxidizing bacterial (AOB) communities in C₄ grassland soils using quantitative PCR, quantitative reverse transcription-PCR, and high-throughput amplicon sequencing of amoA genes.

Results: Nitrosospira were dominant AOB in the C₄ grassland soil throughout the growing season. N fertilization rate had a stronger influence on AOB community composition than C₄ grass species. Elevated N fertilizer application increased the abundance, activity, and alpha-diversity of AOB communities as well as nitrification potential, nitrous oxide (N₂O) emission and soil acidity. The abundance and species richness of AOB were higher under switchgrass compared to big bluestem. Soil pH, nitrate, nitrification potential, and N₂O emission were significantly related to the variability in AOB community structures (p < 0.05).

Keywords: Ammonia oxidizing bacteria; Big bluestem grass; N fertilizer; Soil microbiology; Switchgrass; amoA.

Grants and funding

This work was supported by the United States Department of Agriculture (No. USDA-NIFA 2016-67020-25352). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.