Using different models to estimate N2O fluxes from maize cultivation in Poland

Abstract

This paper presents a comparison of N2O fluxes calculated using empirical and biogeochemical models at the country level applying different climatic conditions. The empirical tools follow Tier 1 and 2 IPCC methods, whereas the process-based model follows Tier 3. In our study the following tools were applied: for Tier 1 – BioGrace calculator, Tier 2 − Lesschen emission factors (Lesschen-EF), and Tier 3 – denitrification decomposition (DNDC) model. The N2O fluxes were calculated for maize grown in four-yr crop rotation in Poland. The same input data were applied in all methods, and the sequence of N2O fluxes from largest to lowest was: BioGrace calculator > Lesschen-EF > DNDC. The average N2O emission from maize cultivation applying IPCC default value was 3.17 kg N ha-1 yr-1. Almost two-fold lower fluxes were calculated based on the Lesschen-EF and DNDC model. At a regional level, the Lesschen-EF as well as DNDC model were performed. Therefore, the Lesschen-EF could be recommended for countries to calculate N2O emissions. The advantage of this approach is simplicity of obtaining the necessary data compared to the processbased model requirements. Additionally, the Tier 2 method offers mitigation measures comparable to the DNDC model, related to crop type, weather conditions, and management practices.