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Evaluating Cropland N 2 O Emissions and Fertilizer Plant Greenhouse Gas Emissions With Airborne Observations
Author(s) -
Gvakharia A.,
Kort E. A.,
Smith M. L.,
Conley S.
Publication year - 2020
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1029/2020jd032815
Subject(s) - greenhouse gas , environmental science , fertilizer , atmospheric sciences , trace gas , agriculture , emission inventory , air pollution , agronomy , chemistry , geography , biology , geology , ecology , archaeology , organic chemistry
Abstract Agricultural activity is a significant source of greenhouse gas emissions. The fertilizer production process emits N 2 O, CO 2 , and CH 4 , and fertilized croplands emit N 2 O. We present continuous airborne observations of these trace gases in the Lower Mississippi River Basin to quantify emissions from both fertilizer plants and croplands during the early growing season. Observed hourly emission rates from two fertilizer plants are compared with reported inventory values, showing agreement for N 2 O and CO 2 emissions but large underestimation in reported CH 4 emissions by up to a factor of 100. These CH 4 emissions are consistent with loss rates of 0.6–1.2%. We quantify regional emission fluxes (100 km) of N 2 O using the airborne mass balance technique, a first application for N 2 O, and explore linkages to controlling processes. Finally, we demonstrate the ability to use airborne measurements to distinguish N 2 O emission differences between neighboring fields, determining we can distinguish different emission behaviors of regions on the order of 2.5 km 2 with emissions differences of approximately 0.026 μ mol m −2 s −1 . This suggests airborne approaches such as outlined here could be used to evaluate the impact of different agricultural practices at critical field‐size spatial scales.