Hafiz Muhammad Hasnain Shah, Zunaira Asif
Abstract:
Agricultural activities contribute significantly to global greenhouse gas (GHG) emissions, making mitigation in cropping systems critical for climate sustainability. This study establishes a robust framework by integrating process-based modeling using the DeNitrification–DeComposition (DNDC) model with a Life Cycle Assessment (LCA) approach to evaluate GHG emissions from corn production. The DNDC model simulates soil nitrous oxide (N₂O) and carbon dioxide (CO₂) fluxes under varying nitrogen management strategies, including urea and urea ammonium nitrate (UAN) applied at different rates and as split applications, while accounting for soil organic carbon (SOC) levels and residue management practices. The LCA combines DNDC-derived soil fluxes with upstream emissions from fertilizer and seed production, field operations, and transportation to provide a cradle-to-farm gate assessment. In contrast to studies dependent entirely on empirical emission factors, this innovative DNDC–LCA framework captures site-specific soil dynamics while linking them to the broader production system, offering a mechanistic and comprehensive evaluation of mitigation strategies. Results show that higher nitrogen application rates substantially increase both fertilizer-related and soil N₂O emissions, with cumulative emissions reaching 2.54 kg N₂O-N ha⁻¹ for urea and 2.40 kg N₂O-N ha⁻¹ for UAN at the highest rate, while split applications reduced emissions to 1.53 kg N₂O-N ha⁻¹ (urea) and 1.45 kg N₂O-N ha⁻¹ (UAN). UAN consistently produces slightly lower emissions than urea. Residue management influences CO₂ fluxes, with aerobic practices such as residue removal or composting reducing emissions in high SOC soils. Sensitivity analysis identifies soil emissions as the dominant contributor to variability, highlighting the importance of site-specific management and accurate emission factor estimation. Comparison with field measurements shows CO₂ emissions are more predictable (R² = 0.62) than N₂O (R² = 0.46). These findings demonstrate that integrated nitrogen and residue management, coupled with attention to soil carbon dynamics, can reduce the carbon footprint of corn production while maintaining productivity. The innovative DNDC–LCA framework establishes a scientific basis to support evidence-based policies that incentivize split nitrogen application, promote lower-emission fertilizer choices, and support sustainable residue management, and provides farmers with practical strategies to reduce emissions without compromising yields.
Keywords: Assessing the Effects of Agricultural Management on GHG Emissions using an Integrated DNDC–LCA Approach
Date Published: October 6, 2025 DOI: 10.11159/ijepr.2025.005
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