Fertilizer management modifies soil CO2, N2O, and CH4 emissions in a Chernozem soil

Abstract

Climate change is an emerging threat to global ecosystems, thus assessing human influences on soil carbon and nitrogen cycles is essential for mitigation policies. We evaluated the effects of different fertilizer applications on CO₂, N₂O, and CH₄ emissions of an Endocalcic Chernozem under maize cropping in a long-term experiment for two consecutive years. We examined soil temperature (Ts), soil water content (SWC), soil chemical parameters, yield and greenhouse gas intensity indexes (GHGI) in the control (C), the manure (M), the fertilized (NPK), and the combined (NPK+M) parcels. We found higher mean CO₂ emissions (0.056 ± 0.040 mg CO₂ m⁻²s⁻¹) in the M treatment compared to the NPK (0.048 ± 0.057 mg CO₂ m⁻²s⁻¹). CO₂ emission showed inconsistent results in both years, highlighting the importance of the duration of the investigations. N₂O emissions were higher under NPK or NPK+M treatments (0.014 ± 0.025 and 0.017 ± 0.026 µg N₂O m⁻² s⁻¹) than under M or control (0.003 ± 0.002 and 0.003 ± 0.002 µg N₂O m⁻² s⁻¹). These results can be attributed to the higher nitrogen contents and lower pH values in the NPK parcels. There were no significant CH₄ emissions under any treatments. Mean Ts and SWC were similar in each treatment indicating their influence on the emissions was rather temporal, than between treatments. Mean GHGI was the lowest in NPK+M, since the yields compensated the elevated emissions. This research highlights the benefits of combined fertilization for chernozem soils in terms of yield and GHGI, which can be useful for selecting proper fertilizer technologies in areas with similar soil characteristics.