Optimization of agronomic management positively affects soil GHG emission: Viable solutions of mitigation in moist and dry Mediterranean climate zones

Abstract

This study assesses the greenhouse gases (GHG) mitigation potential of two cropping systems under the diverse pedoclimatic conditions of two sites in Northern and Southern Italy, belonging to moist and dry climate zones, respectively. The two cropping systems, implemented at field scale in silty-clay-loam soils, were an optimized cropping system (ECS), designed and managed to be more efficient in the use of nitrogen and in the conservation of soil organic carbon (SOC), and a conventional system (CCS). N₂O and CO₂ soil fluxes were measured daily over three to four years using automatic stations comprising eight non-steady-state chambers per site. The ARMOSA model, calibrated and validated with measured data, provided reliable simulations of GHG fluxes and crop yields, aiding environmental impact assessments. In the Northern moist site, the ECS showed a significant GHG mitigation effect, serving as a GHG sink due to reduced N₂O emissions (N input-scaled emission: 0.0030 kg N-N₂O kg N⁻¹). Conversely, the CCS, despite its higher productivity and SOC storage, emitted more N₂O (N input-scaled emissions 0.0051 kg N-N₂O kg N⁻¹), making it a GHG source. In the moist site ECS had an effective mitigation potential compared with CCS, while in the Southern dry site both systems had lower GHG emissions than at the moist site, due to the reduced N rates (-27 % in CCS, −33 % in ECS), thus resulting as GHG sinks. This study underscores the relevance of agronomic mitigation practices, like leguminous crops integration and optimized nitrogen management where GHG emission are fostered by site-specific pedoclimatic conditions.