Global meta-analysis of maize management strategies: yield responses and reactive nitrogen losses across environmental gradients

Abstract Inadequate nitrogen (N) management in maize production causes large losses of reactive nitrogen (Nr) via N 2 O emissions, NH 3 volatilisation and NO 3 − leaching, reducing fertilizer efficiency and contributing to planetary-boundary transgression. This global meta-analysis (3412 observations from 312 field studies in 43 countries) quantified the effects of four fertilization strategies (mineral, organic, enhanced-efficiency fertilizers (EEFs), and combined mineral–organic) on maize yield and the three major Nr loss pathways, while identifying key moderators (management, climate, soil). Effect sizes were calculated as log response ratios and analysed with hierarchical random-effects models and meta-regressions. Combined mineral–organic fertilization produced the largest yield gain (127% [87–175%]) relative to unfertilised controls. EEFs and organic fertilizers minimised N 2 O (174–180%) and NO 3 − leaching (133–141%), while mineral fertilizers caused the highest losses across all pathways. Yield was primarily driven by N rate and soil organic carbon (SOC); N 2 O by soil pH and temperature seasonality; NH 3 by N rate and coarse texture; and NO 3 − leaching by soil pH and texture. Integration of organic with mineral fertilizers or adoption of EEFs offers the best trade-off between productivity and environmental protection. Management should be site-specific, tailored to soil pH, texture, SOC and climate.