DMPSA appliCation reduces N2O emissions from exogenous NH4 + and NO3 - sources in irrigated maize

Abstract

Agriculture is a major anthropogenic source of nitrous oxide (N2O). Application of nitrogenous (N)
fertilizers enhances the emission of this greenhouse gas (GHG), mainly due to the biogenic processes of
nitrification and denitrification. The use of nitrification inhibitors (NIs), that delay the microbial oxidation of
NH4 + to NO3 -, has been reported as a successful tool for mitigating N2O losses. In this context, a field
experiment using 15N labeled fertilizers was carried out in an irrigated Mediterranean maize field aiming to
evaluate the effectiveness of the NI 2-(3,4-dimethyl-1H-pyrazol-1-yl) succinic acid isomeric mixture
(DMPSA) on mitigating N2O emissions, and assess the processes involved in its production. The experiment,
performed in 1 m2 microplots, involved the application of 15NH4NO3 or NH4 15NO3 - (with and without DMPSA) to quantify the amount of N2O coming from exogenous NH4 +, exogenous NO3 - and endogenous soil N. The resulting N2O fluxes confirmed that the addition of DMPSA led to a significant (54%) abatement of this GHG. In this experiment, both nitrification and denitrification were partially inhibited by DMPSA.
When NI was not applied, the largest N2O emissions were expected from NH4 + than from NO3 --based fertilizers due to nitrification.