AUTHOR=Chiaravalloti Isabella , Theunissen Nicolas , Zhang Shuang , Wang Jiuyuan , Sun Fengchao , Ahmed Ayesha A. , Pihlap Evelin , Reinhard Christopher T. , Planavsky Noah J. 

TITLE=Mitigation of soil nitrous oxide emissions during maize production with basalt amendments

JOURNAL=Frontiers in Climate

VOLUME=5

YEAR=2023

URL=https://www.frontiersin.org/journals/climate/articles/10.3389/fclim.2023.1203043

DOI=10.3389/fclim.2023.1203043

ISSN=2624-9553

ABSTRACT=<p>Nitrous oxide (N<sub>2</sub>O) is a potent and long-lived greenhouse gas that accounts for roughly 6% of global anthropogenic greenhouse gas emissions, and it has risen from its preindustrial concentration of 270 ppb N<sub>2</sub>O to 332 ppb N<sub>2</sub>O as a result of human activities. The majority of anthropogenic N<sub>2</sub>O emissions (52–80%) come from agricultural settings due to high rates of reactive nitrogen fertilizer application. Amending soils with fine-grained basalt is gaining traction as a carbon dioxide removal (CDR) pathway, and model simulations suggest that this process may also significantly decrease soil N<sub>2</sub>O emissions. Here, we continuously measure N<sub>2</sub>O fluxes from large-scale maize mesocosms in a greenhouse setting and use a machine learning framework to assess the relative importance of the levers on N<sub>2</sub>O fluxes. We observe significant decreases in cumulative N<sub>2</sub>O emissions (between 29–32%) from mesocosm systems with basalt addition. We find that basalt application rate, soil pH, and surface soil moisture are the strongest levers on N<sub>2</sub>O emissions depending on the system settings. These results provide empirical support for a potentially significant co-benefit of deploying enhanced rock weathering of silicates (ERW) on managed lands, particularly those subject to elevated rates of reactive nitrogen input.</p>