ABSTRACT Excessive nitrogen (N) inputs in warm and wet sugarcane cropping systems lead to substantial ammonia (NH 3 ) volatilization, nitrous oxide (N 2 O) emission, nitrate (NO 3 − ) leaching, and dissolved inorganic N (DIN) runoff, posing risks to air quality, aquatic ecosystems, and climate forcing. A global, integrative understanding of the drivers of these loss pathways and the effectiveness of management practices is required to balance sugarcane productivity with reductions in environmental N pollution across diverse sugarcane regions. Here we synthesized data from global sugarcane experiments to derive region‐specific emission factors (EFs) for multiple N loss pathways and to identify key biophysical and management controls on N losses, crop yield, and their trade‐offs. Brazil showed the highest NH 3 volatilization EF (7.4%); Australia the highest N 2 O emission EF (2.6%); and Brazil the highest NO 3 − leaching EF (8.9%), highlighting strong regional contrasts in N loss dynamics. Across regions, N application rate and cane trash retention were major regulators of NH 3 volatilization, with surface trash retention overriding soil pH and clay effects. N 2 O emissions increased with high N inputs and carbon availability, but were negatively associated with water inputs, suggesting enhanced complete denitrification under wetter conditions. High N and water inputs increased DIN runoff. Increasing N input enhanced sugarcane yield but also amplified all major N loss pathways. Cane trash retention increased yield but raised NH 3 and N 2 O losses, whereas adding carbon‐rich sugar mill by‐products reduced NH 3 but increased N 2 O emissions. Urease and nitrification inhibitors effectively reduced NH 3 and N 2 O losses, respectively, while controlled‐release fertilizers showed inconsistent impacts. Scenario‐based modelling demonstrates trade‐offs between N loss reduction and productivity, with urease and nitrification inhibitors substantially reducing N losses without compromising yield, outperforming strategies based solely on N rate reduction or cane trash removal. These findings together inform sustainable N management strategies that mitigate environmental impacts while maintaining sugarcane productivity.
Sukdanont et al. (Mon,) studied this question.