Soil Nitrogen Emissions Modeling

Emissions of reactive nitrogen compounds from soil are important, but potentially underestimated, contributors to atmospheric chemistry. In particular, some studies suggest soil emissions of NO may be twice as large as previous estimates; other studies suggest soils represent a previously unrecognized source of HONO. Our group implemented into the Community Multiscale Air Quality (CMAQ) model a state-of-the-science soil parametric NO emissions scheme, which better represents their responsiveness to meteorology. We then enhanced a mechanistic agroecosystem model, FEST-C, by incorporating nitrogen cycling schemes from DayCENT, and used it to simulate how meteorological conditions, farming practices, and soil properties influence the emissions of not only NO but also N₂O and NH₃. We are investigating how this new scheme affects simulation of air pollutants observed by satellites and in situ monitors. Ongoing work will seek to further enhance model estimates of soil emissions of a range of nitrogen species, and characterize how they are influenced by fertilizer application, soil carbon amendments, and other agricultural management practices.

Funding: NASA, Carbon Hub

Recent publications:

• Luo et al., 2022. Integrated Modeling of U.S. Agricultural Soil Emissions of Reactive Nitrogen and Associated Impacts on Air Pollution, Health, and Climate. Environmental Science & Technology, https://doi.org/10.1021/acs.est.1c08660
• Rasool et al., 2019. Mechanistic representation of soil nitrogen emissions in the Community Multiscale Air Quality (CMAQ) model v 5.1. Geoscientific Model Development, https://www.geosci-model-dev.net/12/849/2019/
• Zhang et al., 2018. Incorporating GOES satellite photosynthetically active radiation (PAR) retrievals to improve biogenic emission estimates in Texas. Journal of Geophysical Research, https://doi.org/10.1002/2017JD026792
• Pourhashem et al., 2017. Valuing the air quality effects of biochar reductions on soil NO emissions. Environmental Science & Technology, https://doi.org/10.1021/acs.est.7b00748
• Rasool et al., 2017. Enhanced representation of soil NO emissions in the Community Multi-scale Air Quality (CMAQ) model version 5.0.2. Geoscientific Model Development, https://doi.org/10.5194/gmd-9-3177-2016