Skip to main content

Gross N transformation rates in soil system with contrasting Urochloa genotypes do not confirm the relevance of BNI as previously assessed in vitro

Abstract

The capacity of several plant species or landraces to inhibit nitrification in soil (biological nitrification inhibition, BNI) has been assessed in certain tropical pastures. These assessments are commonly based on potential net nitrification rates, which do not differentiate between gross nitrification and other processes that may reduce the amount of nitrate in soil. In a greenhouse experiment using two genotypes of Urochloa humidicola with contrasting BNI capacity in vitro, we evaluated gross N transformation rates before and after (7 and 21 days) N fertilization, while periodically measuring N2O emissions. Gross nitrification rates (in fact gross nitrate production assessed by pool dilution technique) were comparable in both genotypes and were low in comparison to strong microbial NH4+ immobilization. The N2O emissions were higher in pots with low-BNI plants. The discrepancy between the potential net nitrification rates assessed in laboratory assays (higher in low-BNI plants) and gross nitrification in pot or field experiments (no differences between genotypes) can be attributed to the out-competition of ammonia oxidizers by plant N uptake and ammonia immobilizing heterotrophic microbes, resulting in low nitrification under conditions where growing plants are present. This study confirmed the capacity of certain U. humidicola genotypes to reduce N2O emissions but warrants further investigation of the underlying mechanisms. It also questions the relevance of BNI in the rhizosphere of this plant species as other mechanisms (rather than the inhibition of gross nitrification) seem to be more important in maintaining low-nitrate soil environments in soil–plant systems of U. humidicola.

This is a preview of subscription content, access via your institution.

Fig. 1
Fig. 2
Fig. 3

References

Download references

Acknowledgements

We thank all the CIAT staff who collaborated with the soil collection, experiment establishment and maintenance at CIAT Headquarters in Palmira, Colombia. In addition, Eduardo Vázquez thanks the Spanish Ministry of Education for his FPU fellowship.

Funding

This work was implemented as part of the CGIAR Research Programs (CRP) on Climate Change, Agriculture and Food Security (CCAFS); and the Livestock CRP. We gratefully acknowledge funding from BBSRC project grants RCUK-CIAT Newton Fund—Advancing sustainable forage-based livestock production systems in Colombia (CoForLife) (BB/S01893X/1), and the UKRI Global Challenges Research Fund (GCRF) GROW Colombia grant via the UK’s BBSRC (BB/P028098/1). Financial support was also obtained from the Internal Grant Agency of Czech University of Life Sciences Prague (20213110) and from Center for Geosphere Dynamics (UNCE/SCI/006).

Author information

Authors and Affiliations

Authors

Corresponding authors

Correspondence to Nikola Teutscherová or Eduardo Vázquez.

Ethics declarations

Conflict of interest

The authors declare no competing interests.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary Information

Below is the link to the electronic supplementary material.

Supplementary file1 (DOCX 86 KB)

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Teutscherová, N., Vázquez, E., Trubač, J. et al. Gross N transformation rates in soil system with contrasting Urochloa genotypes do not confirm the relevance of BNI as previously assessed in vitro. Biol Fertil Soils 58, 321–331 (2022). https://doi.org/10.1007/s00374-021-01610-z

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s00374-021-01610-z

Keywords

  • Tropical forage
  • Gross nitrogen transformations
  • Urochloa humidicola (Rendle) Schweick (syn. Brachiaria humidicola)
  • N2O emissions
  • Biological nitrification inhibition