Denitrification plays a critical role in regulating ecosystem nutrient availability and anthropogenic reactive nitrogen (N) production. Its importance has inspired an increasing number of studies, yet it remains the most poorly constrained term in terrestrial ecosystem N budgets. We censused the peer‐reviewed soil denitrification literature (1975–2015) to identify opportunities for future studies to advance our understanding despite the inherent challenges in studying the process. We found that only one‐third of studies reported estimates of both nitrous oxide (N2O) and dinitrogen (N2) production fluxes, often the dominant end products of denitrification, while the majority of studies reported only net N2O fluxes or denitrification potential. Of the 236 studies that measured complete denitrification to N2, 49% used the acetylene inhibition method, 84% were conducted in the laboratory, 81% were performed on surface soils (0–20 cm depth), 75% were located in North America and Europe, and 78% performed treatment manipulations, mostly of N, carbon, or water. To improve understanding of soil denitrification, we recommend broadening access to technologies for new methodologies to measure soil N2production rates, conducting more studies in the tropics and on subsoils, performing standardized experiments on unmanipulated soils, and using more precise terminology to refer to measured process rates (e.g., net N2O flux or denitrification potential). To overcome the greater challenges in studying soil denitrification, we envision coordinated research efforts based on standard reporting of metadata for all soil denitrification studies, standard protocols for studies contributing to a Global Denitrification Research Network, and a global consortium of denitrification researchers to facilitate sharing ideas, resources, and to provide mentorship for researchers new to the field.
This content will become publicly available on February 1, 2025
Nitrous oxide (N2O) is a potent greenhouse gas that contributes to stratospheric ozone depletion and global climate change. Soil denitrification has two potential end-products, N2O and dinitrogen (N2), and the ratio of these end-products (N2O:(N2O+N2) or the N2O ratio) is controlled by various factors. This study aims to quantify the influence of soil pH on the ratio of denitrification end-products in Oklahoma soils with different soil textures. Six natural grassland soils encompassing three distinct soil textures were incubated in the laboratory under natural and modified pH with an overall tested pH ranging from 2 to 10. Denitrification end-products were measured in the laboratory using the acetylene inhibition technique and further estimated using a process-based biogeochemical model. Both the laboratory and model results showed that soil pH and texture influenced the ratio of the denitrification end-products. Generally, as soil pH increased the N2O ratio decreased, although both lab and model results indicated that this relationship was not linear. Soil texture may have an indirect effect on the N2O ratio, as two soils of the same texture could have different N2O ratios. However, clay percentage of the soil did show a linear positive correlation with the N2O ratio, suggesting components of soil texture may be more influential than others. Overall, soil pH was a controlling factor in the ratio of denitrification end-products and the newly observed nonlinear relationship warrants further study, particularly when considering its effects in different soil textures.
more » « less- Award ID(s):
- 1946093
- NSF-PAR ID:
- 10494900
- Publisher / Repository:
- ResearchGate
- Date Published:
- Journal Name:
- Frontiers in Soil Science
- Volume:
- 4
- ISSN:
- 2673-8619
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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