Microbial Urease and Climate Change: Exploring the Potential for Reduced Nitrous Oxide Emissions in Agriculture

Abstract

Agricultural soils generate ~60% of anthropogenic nitrous oxide (N₂O) emissions, primarily through microbial urease activity during urea hydrolysis. With N₂O possessing 265× CO₂'s global warming potential, effective mitigation strategies must balance emission reductions with maintained crop productivity. Urease inhibitors (NBPT/HQ), controlled-release fertilizers, and microbiome modifications show promise, with efficacy varying by soil type (pH, texture), climate, and management practices. Field trials and meta-analyses (2010-2024) demonstrate these approaches can achieve 30-50% N₂O reductions without yield penalties when properly implemented. To evaluate urease inhibition as an N₂O mitigation tool by synthesizing global evidence (2010-2024) and quantifying its efficacy across soil types, crops, and climates. This systematic review (2010-2024) synthesizes data from Web of Science, Scopus, and GRACEnet to evaluate urease inhibition impacts on agricultural N₂O emissions. Incorporating field trials and controlled studies, we employed meta-analytic methods (R metafor package) to quantify effect sizes, assess heterogeneity, and visualize responses. Our interdisciplinary approach analyzed treatment efficacy across soil types and management practices, providing robust evidence for climate-smart mitigation strategies. Urease inhibitors reduced N₂O emissions by 42% (95% CI: 35–50%) vs. conventional urea, with peak efficacy in clay soils (48% reduction) and humid climates. NBPT outperformed HQ (p < 0.01), especially in neutral-pH soils. Crop yields increased marginally (+3.5%), and NUE improved by 18%. However, sandy soils showed lower efficacy (28% reduction). Meta-regression linked inhibitor performance to soil organic carbon (R² = 0.67) and precipitation (R² = 0.53). Urease inhibitors are a robust N₂O mitigation tool, but soil-specific adoption is vital. Integrating them with nitrification inhibitors or biochar could enhance gains. Scaling requires policy incentives and farmer education to address cost and knowledge barriers.