Lab member Facundo Lussich recently published an article titled, “Cover crop residue decomposition triggered soil oxygen depletion and promoted nitrous oxide emissions.” Lussich found that soil residue decomposition depletes soil oxygen, thus leading to soil anoxia (even in relatively drier soil) which promoted denitrification and nitrous oxide emissions.
The article highlighted a 21-day incubation experiment that was held to examine the effects of contrasting cover crop residue (grass vs legume) decomposition on soil oxygen (O2) and biogeochemical changes to influence nitrous oxide (N2O) and carbon dioxide (CO2) emissions from fertilized soils under 50% and 80% Water Filled Pore Space (WFPS) levels. Irrespective of cover crop type, mixing cover crop residue with N fertilizer resulted in high cumulative N2O emissions under both WFPS conditions. In the absence of cover crop residues, the N fertilizer effect of N2O was only realized under 80% WFPS, whereas it was comparable to the control under 50% WFPS. The N2O peaks under 50% WFPS coincided with soil O2 depletion and concomitant high CO2 emissions when cover crop residues were mixed with N fertilizer. While N fertilizer largely contributed to the total N2O emissions from the cover crop treatments, soil organic matter and/or cover crop residue derived N2O had a greater contribution under 50% than 80% WFPS.
Lussich suggests that the results underscore the importance of N2O emissions from cover crop-based fertilized systems under relatively lower WFPS via a mechanism of respiration-induced anoxia and highlight potential risks of underestimating N2O emissions under sole reliance on WFPS. He wishes to give a special thanks to USDA NIFA for their invaluable funding support.
You can read the article, by clicking here or by using the citation below.
Lussich, F., Dhaliwal, J. K., Faiia, A. M., Jagadamma, S., Schaeffer, S. M., & Saha, D. (2024). Cover crop residue decomposition triggered soil oxygen depletion and promoted nitrous oxide emissions. Scientific Reports, 14(1), 8437. https://doi.org/10.1038/s41598-024-58942-7