Effects of soil compaction on GHGs emissions in different cultivation systems

Soil compaction plays a critical role in altering nutrient cycling, with risks of air and water contamination, reduced crop productivity. Practices such as conservation agriculture are promoted for their potential to reduce agriculture's impact on environment. Conservation methods can sometimes contribute to soil compaction, hence the necessity of more research on how soil compaction interact with crop management practices and digestate fertilization. This study evaluated the impact of different soil management practices, conventional agriculture (CV), conservation agriculture with shallow and deep compaction (CA1 and CA2), cover cropping (CC), and bare soil (BS), on greenhouse gas (GHG) emissions. A system of 20 lysimeters with a non-steady state through-flow chamber system coupled with an FTIR gas analyzer was used to continuously monitoring daily GHGs (CO₂, CH₄, and N₂O) fluxes. Results showed that non-compacted treatments achieved higher maize yields than compacted ones, with CV reaching the regional trend of 10 Mg ha⁻¹. Despite similar nitrogen concentrations across treatments, nutrient uptake was significantly higher in CV due to better root development and biomass production. CO₂ emissions peaked following digestate application, especially in CV, due to greater microbial and root respiration. All treatments acted as CH₄ sinks, with the highest uptake in CV and the lowest in compacted treatments, attributed to reduced soil aeration. N₂O emissions were strongly linked to post-fertilization periods, with CV exhibiting the highest cumulative emissions. No clear difference in N₂O emissions was found between compacted and non-compacted conservation systems, and BS showed high nitrate leaching, indicating a potential for indirect N₂O emissions. This study allowed to follow some of the dynamics related to different agricultural practices and their relationship with GHGs emission, recognizing the importance of further research to fill the gaps.