A two-year field study was conducted to test the hypothesis that biochar application increases inorganic soil N availability during maize growth, leading to higher grain yields and N recovery efficiency while reducing the risk of N leaching following harvest. Four N fertilizer rates (0, 90, 179, and 269 kg ha-1 as urea ammonium nitrate solution) were applied with or without biochar (10 Mg ha-1) before maize planting each year. This dataset contains selected summary statistics (average and standard deviation) on soil and plant measurements. This file package also includes a readme.txt file that describes the data in detail, including attribute descriptions.