Intra‐ and inter‐annual variability of nitrification in the rhizosphere of field‐grown bioenergy sorghum
- Center for Advanced Bioenergy and Bioproducts Innovation Urbana Illinois USA, University of Illinois at Urbana‐Champaign Institute for Genomic Biology Urbana Illinois USA
- Center for Advanced Bioenergy and Bioproducts Innovation Urbana Illinois USA, Department of Biology West Virginia University Institute of Technology Beckley West Virginia USA
- Center for Advanced Bioenergy and Bioproducts Innovation Urbana Illinois USA, University of Illinois at Urbana‐Champaign Institute for Genomic Biology Urbana Illinois USA, Department of Crop Sciences University of Illinois at Urbana‐Champaign Urbana Illinois USA
- Center for Advanced Bioenergy and Bioproducts Innovation Urbana Illinois USA, University of Illinois at Urbana‐Champaign Institute for Genomic Biology Urbana Illinois USA, Department of Natural Resources and Environmental Sciences University of Illinois at Urbana‐Champaign Urbana Illinois USA
- Center for Advanced Bioenergy and Bioproducts Innovation Urbana Illinois USA, University of Illinois at Urbana‐Champaign Institute for Genomic Biology Urbana Illinois USA, Department of Plant Biology University of Illinois at Urbana‐Champaign Urbana Illinois USA, Institute for Sustainability, Energy, and Environment University of Illinois at Urbana‐Champaign Urbana Illinois USA
- Center for Advanced Bioenergy and Bioproducts Innovation Urbana Illinois USA, University of Illinois at Urbana‐Champaign Institute for Genomic Biology Urbana Illinois USA, Department of Plant Biology University of Illinois at Urbana‐Champaign Urbana Illinois USA, Institute for Sustainability, Energy, and Environment University of Illinois at Urbana‐Champaign Urbana Illinois USA, Department of Geology University of Illinois at Urbana‐Champaign Urbana Illinois USA
Abstract Biological nitrification inhibition (BNI) and plant–microbe competition for ammonium (NH 4 + ) by sorghum ( Sorghum bicolor (L.) Moench) have the potential to suppress nitrification, reducing nitrate (NO 3 − ) and nitrous oxide (N 2 O) production for more sustainable bioenergy feedstock production. However, it is unknown how variability in environmental factors, field management, and plant growth affect the suppression of nitrification. We conducted a field trial with four genotypes of energy sorghum and four fertilization rates in central Illinois, USA, and measured soil N pools, potential nitrification and denitrification rates, and microbial community composition in bulk and rhizosphere soils to assess nitrification suppression throughout the 2018 and 2019 growing seasons. Concentrations of NO 3 − and NH 4 + were very low in rhizosphere soil regardless of fertilization level, suggesting strong N demand by plants and microbes. Potential nitrification was lower in the rhizosphere soil than bulk soil, and this suppression was strongest mid‐season ~2 months after planting in both years (20% suppression in 2018 and 58% in 2019). Since precipitation was lower during the mid‐growing season of 2019 compared to 2018, we speculate that hydrophilic BNI root exudates accumulated in the rhizosphere and suppressed nitrification more than in 2018 when soil moisture was higher. Unfertilized plots had greater nitrification suppression than fertilized plots during the mid‐season in 2018, but otherwise nitrification suppression was insensitive to fertilizer treatment. Potential denitrification was stimulated in the rhizosphere compared to bulk soil in both study years, suggesting that heterotrophic activity was stimulated by plant carbon inputs, possibly further suppressing slower‐growing chemoautotrophic nitrifying microbes. Overall, we found inter‐ and intra‐annual variation in nitrification suppression in the rhizosphere of field‐grown biomass sorghum, suggesting that plant phenology and environmental conditions should be considered when devising strategies to improve the nitrogen sustainability of this annual bioenergy crop.
- Research Organization:
- Center for Advanced Bioenergy and Bioproducts Innovation (CABBI), Urbana, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Biological and Environmental Research (BER)
- Grant/Contract Number:
- DE‐SC0018420; SC0018420
- OSTI ID:
- 1838893
- Alternate ID(s):
- OSTI ID: 1839620; OSTI ID: 1996845
- Journal Information:
- Global Change Biology. Bioenergy, Journal Name: Global Change Biology. Bioenergy Vol. 14 Journal Issue: 3; ISSN 1757-1693
- Publisher:
- Wiley-BlackwellCopyright Statement
- Country of Publication:
- United Kingdom
- Language:
- English
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