New paper out on cover crops effects on N2O emissions over multiple freeze-thaw events

New open access paper published in the Canadian Journal of Soil Science from Yuanpei Gao's MSc research at the University of Guelph. Find it here: https://cdnsciencepub.com/doi/full/10.1139/cjss-2023-0017

We used the flux gradient method to continuously measure N2O emissions from a conventional corn–soybean rotation. We investigated the effects of summer-established cover crops and interactive effects of fall cultivation (tillage) practices in the fall, which is a management approach used to terminate cover crops. Measurements were taken over a six-month non-growing season that was characterized by several freezing and thawing periods (i.e., weather events in cold climates that lead to significant contributions of total N2O emissions).

Total non-growing season emissions varied nearly 2.5-fold among treatments from 395.1 (no cover crop and no fall cultivation) to 978.1 (cover crop plus fall cultivation) g N2O-N ha−1. Compared with the control treatment (no cover crop and no fall cultivation), just fall cultivation alone and cover crops alone increased total non-growing season N2O emissions, while cover crops with fall cultivation increased N2O fluxes even more. Careful cover crop species selection and management are important to avoid elevated non-growing season emissions.

Nongrowing season soil nitrous oxide emissions as influenced by cover crops and fall tillage termination

Authors: Yuanpei Gao, Kira A. Borden, Shannon E. Brown, and Claudia Wagner-Riddle

Publication: Canadian Journal of Soil Science https://doi.org/10.1139/cjss-2023-0017

Cumulative N2O emissions (g N2O-N ha−1) measured from 31 October 2018 to 30 April 2019 with labeled day of year representing the first of each month between November 2018 and May 2019. Colored solid lines represent daily main N2O flux measured from each field, and segments of period divided by grey, vertical dashed lines represent prefreeze, freezing (“F”), or thawing (“T” or “Final Thaw”) periods. (from Gao et al. 2023)