Replication Data for: Split Nitrogen Application to Soil Improves Corn Agronomic Performance and Nitrogen Use Efficiency

Corn (Zea mays L.) production requires substantial nitrogen (N) during the grain-filling reproductive stages. Delaying split N application until the silking stage (R1) may improve agronomic performance and reduce environmental N losses. This study evaluated the effects of split and reduced N applications on corn growth, yield, soil residual nitrogen, and nitrogen use efficiency (NUE) under rainfed conditions in Central Texas over two contrasting seasons. Ten treatments were tested, including split applications ranging from 100:0 to 50:50 (planting:R1) and reduced rates at 50% and 25% of the full N recommendation. In 2021, with adequate rainfall, split applications had no significant effect on aboveground biomass or grain yield, although delaying 50% of N to R1 reduced leaf area index (LAI) and chlorophyll content. In 2022, under severe drought, overall plant performance declined. However, reducing N to 50% did not affect biomass or yield compared to full rates, but improved N uptake and agronomic efficiency while reducing residual soil nitrate. The 25% N rate significantly reduced corn growth and yield. These findings suggest that applying 50% of N at planting allows flexibility to adjust remaining applications based on in-season weather. Adaptive N strategies can maintain productivity, enhance NUE, and reduce environmental risk in dryland corn systems under variable climatic conditions.