Sustainable nitrogen management strategies for reducing environmental footprint of cereal production

Abstract

Cereal farmers across sub-Saharan Africa lose more nitrogen to the environment than they deliver to the grain. This research compared five nitrogen management strategies—conventional broadcast, split application, slow-release fertiliser, precision placement, and nitrification inhibitor-coated urea—for their effects on NUE, N₂O emissions, grain yield, and nitrate leaching in a maize-sorghum system. A two-year field trial (2021-2023) at the University of Ibadan used a randomised complete block design. Precision placement raised NUE from 27.4% to 53.8% while maintaining yields within 4% of the highest treatment. Inhibitor-coated urea cut N₂O emissions by 64.7%. These results show that targeted application methods can sharply reduce nitrogen losses without sacrificing productivity.