Journal article
Mining the Drilosphere: Bacterial Communities and Denitrifier Abundance in a No-Till Wheat Cropping System
Frontiers in microbiology, Vol.10, p.1339
2019
Handle:
https://hdl.handle.net/2376/115110
PMCID: PMC6611406
PMID: 31316473
Abstract
Earthworms play important roles in no-till cropping systems by redistributing crop residue to lower soil horizons, providing macropores for root growth, increasing water infiltration, enhancing soil quality and organic matter, and stimulating nitrogen cycling. The soil impacted by earthworm activity, including burrows, casts, and middens, is termed the drilosphere. The objective of this study was to determine the effect of earthworms on soil microbial community composition in the drilosphere at different landscape slope positions. Soil cores (50 cm depth) were extracted from three landscape locations (top, middle, and bottom slope positions) on a sloping aspect of a no-till wheat farm. Soil was sampled at the bottom of the soil core from inside multiple earthworm (
) channels (drilosphere) and from adjacent bulk soil. Bacterial communities were characterized for 16S rRNA gene diversity using high-throughput sequencing and functional denitrifier gene abundance (
, and
) by quantitative PCR. Bacterial communities were structured primarily by the landscape slope position of the soil core followed by source (bulk versus drilosphere soil), with a significant interaction between core position and source. The families AKIW874, Chitinophagaceae, and Comamonadaceae and the genera
, and
were more abundant in the drilosphere compared to the bulk soil. Most of the individual bacterial taxa enriched in the drilosphere versus bulk soil were members of Actinobacteria, including Micrococcales, Gaiellaceae, Solirubrobacterales, and
. In general, the greatest differences in communities were observed in comparisons of the top and bottom slope positions in which the bottom slope communities had significantly greater richness, diversity, and denitrifier abundance than the top slope position. Populations of denitrifiers (i.e., ratio of
+
to 16S rRNA) were more abundant in earthworm-impacted soils and there was a significant impact of
on soil community composition which was observed only in the top landscape position. There were significant correlations between the abundance of
and
and taxa within Proteobacteria, Acidobacteria, Actinobacteria, Verrucomicrobia, and Chloroflexi, suggesting a broad diversity of denitrifying bacteria. Earthworms influence the soil microbial communities, but the impact depends on the slope location in a variable landscape, which likely reflects different soil characteristics.
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Details
- Title
- Mining the Drilosphere: Bacterial Communities and Denitrifier Abundance in a No-Till Wheat Cropping System
- Creators
- Daniel C Schlatter - Wheat Health, Genetics and Quality Research Unit, Agricultural Research Service, United States Department of Agriculture, Pullman, WA, United StatesCatherine L Reardon - Soil and Water Conservation Research Unit, Agricultural Research Service, United States Department of Agriculture, Adams, OR, United StatesJodi Johnson-Maynard - Department of Soil and Water Systems, University of Idaho, Moscow, ID, United StatesErin Brooks - Department of Soil and Water Systems, University of Idaho, Moscow, ID, United StatesKendall Kahl - Department of Soil and Water Systems, University of Idaho, Moscow, ID, United StatesJessica Norby - Department of Soil and Water Systems, University of Idaho, Moscow, ID, United StatesDavid Huggins - Northwest Sustainable Agroecosystems Research Unit, Agricultural Research Service, United States Department of Agriculture, Pullman, WA, United StatesTimothy C Paulitz - Wheat Health, Genetics and Quality Research Unit, Agricultural Research Service, United States Department of Agriculture, Pullman, WA, United States
- Publication Details
- Frontiers in microbiology, Vol.10, p.1339
- Academic Unit
- Crop and Soil Sciences, Department of; Plant Pathology, Department of
- Publisher
- Switzerland
- Identifiers
- 99900547698401842
- Language
- English
- Resource Type
- Journal article