International Journal of Plant & Soil Science

Global agriculture faces a compound challenge: producing sufficient food for a growing population while dramatically reducing its environmental footprint. Fertilizers—particularly synthetic nitrogen compounds—underpin modern crop yields, yet their overuse drives nitrous oxide (N₂O) emissions, nitrogen leaching, soil acidification, and threats to planetary biogeochemical cycles. Climate-smart agriculture (CSA) offers an integrative framework that seeks simultaneously to raise productivity, build resilience, and reduce greenhouse gas (GHG) emissions. Central to this framework is fertilizer use efficiency (FUE), defined broadly as the ratio of crop output relative to nutrient inputs. This critical review synthesises evidence across the global literature on the agronomic, environmental, and soil-health dimensions of FUE in CSA systems. Drawing on peer-reviewed research published predominantly since 2001 to present; it evaluates the mechanisms by which conventional fertilizer management contributes to GHG emissions and soil degradation; examines enhanced-efficiency fertilizers, precision agriculture, integrated soil fertility management, biochar, cover crops, and biological nitrogen fixation as mitigation pathways; and assesses the tensions between maximising yield and minimising environmental harm. The review identifies significant advances in FUE technologies and management but also highlights persistent knowledge gaps, particularly around context-specific adoption barriers in smallholder systems, long-term soil health trajectories, and coherent policy architectures. A synthesis of the evidence suggests that no single intervention is adequate; rather, portfolios of complementary, site-adapted practices—underpinned by robust policy incentives—are necessary to reconcile food security, climate mitigation, and soil health within planetary boundaries.