Effect of biochar amendment and nitrogen fertilization on soil CO₂ emission during spring period

Biochar application to agriculture soil has been recommended as a strategy to reduce increasing CO₂ emission in the atmosphere and mitigate climate change. In this study, we evaluated the impact of two doses of biochar (10 and 20 t.ha⁻¹) applied in 2014 and reapplied in 2018 combined with three fertilization levels (N0, N1, N2) on carbon dioxide emissions and selected physical and chemical soil properties in field conditions during spring season (April–June) in 2020. The field site is situated in the Nitra region of Slovakia (Malanta). The soil in the field was classified as a silt loam Haplic Luvisol. In this field research it was found that biochar application mostly in all treatments decreased cumulative CO₂ emissions in rage from 4.2% to 30.4% compared to controls (B0N0, B0N2), except treatments where biochar was applied with lower level of N-fertilizer (N1) and treatment B20N0. According to our study results, it was confirmed that biochar can be a promising material for improving soil physical and chemical properties. Mainly, it has very good impact on soil pH, even after seven years of field experiment established. However, the response of soil CO₂ fluxes to biochar application were regulated mainly by experiment length, biochar application rate, biochar properties, giving a new perspective for more comprehensive understanding on biochar.