Soil Nitrous Oxide Emissions Following Crop Residues Management in Corn-Wheat Rotation Under Conventional and No-Tillage Systems
Morad Mirzaei, Manouchehr Gorji Anari, Arezoo Taghizadeh‐Toosi, Mohammad Zaman, Nermina Saronjic, Safwan Mohammed, Szilárd Szabó, Andrés Caballero‐Calvo
Abstract
Agricultural activity is the major anthropogenic source of nitrous oxide (N 2 O) emissions from terrestrial ecosystems. Conservation agriculture including crop residue management can play a key role in enhancing soil resilience to climate change and mitigating N 2 O emissions. We investigated the effects of crop residue rates, including 100 % (R 100 ), 50 % (R 50 ), and residue removal (R 0 ), on N 2 O emissions in corn-wheat rotation under conventional (CT) and no-tillage (NT) systems. The key factors evaluated affecting N 2 O emissions included soil temperature, soil moisture, soil ammonium, and soil nitrate concentrations. Results showed that the N 2 O emissions increased with the increasing rate of residue under both CT and NT systems. Both R 100 and R 50 significantly ( p < .05) increased the N 2 O emissions compared to R 0 during the annual rotation cycle. Soil moisture and mineral nitrogen (ammonium and nitrate) were the main driving factors that stimulated N 2 O emission in both CT and NT systems. In the NT and CT systems, cumulative N 2 O emissions showed a significant increase with R 50 (+75.5 % in NT, +36.5 % in CT) and R 100 (+134 % in NT, +40 % in CT) as compared to R 0 . Furthermore, no significant differences were found between R 100 and R 50 in the CT system, while in the NT system significant increases were observed for R 100 compared to R 50 . Overall, our study justified as a first approach only during the first year that crop residue removal led to decreased N 2 O emissions under semi-arid conditions. However, due to the deteriorating impact of crop residue removal on crop productivity and soil C sequestration, this management method cannot be considered a sustainable agronomic practice. We suggest long-term studies to determine the appropriate rate of postharvest crop residue to achieve less N 2 O emissions and climate-friendly agricultural practices.