Assessment of soil conditions and nitrous oxide emissions from soil in rapeseed and maize cultivation for energy purposes in Poland

Abstract

The aim of the study was to determine nitrous oxide (N2O) emissions in rapeseed and maize grain cultivation in accordance with the requirements of the Renewable Energy Directive (RED2) regarding the cultivation of biofuel crops. The EU Implementing Regulation 2022/996 introducing the updated methodology recommends the use of the Stehfest and Bouwman (S&B) Tier 2 model to determine direct nitrous oxide (N2O) emissions from soil following fertilizer application and the IPCC (Tier 1) methodology for other sources of N2O emissions. The study was based on survey data from 1525 farms; while soil parameters required by the S&B model (pH, soil organic carbon content and texture) were supplemented from the IUNG-PIB soil map where survey’s data were missing. The calculated N2O emissions were aggregated to NUTS2 regions for Poland. Differences in emissions were linked to local agricultural practices (mainly fertilization levels) and soil conditions. The use of the S&B model increases the direct N2O emission factor from fertilizers applied to fine soils or soils with an organic carbon content greater than 3%, compared to the IPCC Tier 1 methodology.