Nitrogen — Open Access Journal

Nitrogen (N) losses from field crops have raised environmental concerns. This manuscript accompanies a database of N loss studies from non-legume field crops conducted across the conterminous United States. Cumulative N losses through nitrous oxide-denitrification (CN₂O), ammonia volatilization (CNH₃), and nitrate leaching (CNO₃⁻) during the growing season and associated crop, soil, and water management information were gathered to determine the extent and controls of these losses. This database consisted of 404, 26, and 358 observations of CN₂O, CNH_3, and CNO₃⁻ losses, respectively, from sixty-two peer-reviewed manuscripts. Corn (Zea mays) dominated the N loss studies. Losses ranged between −0.04 to 16.9, 2.50 to 50.9, and 0 to 257 kg N ha⁻¹ for CN₂O, CNH₃ and CNO₃⁻, respectively. Most CN₂O and CNO₃⁻ observations were reported from Colorado (n = 100) and Iowa (n = 176), respectively. The highest values of CN₂O, and CNO₃⁻ were reported from Illinois and Minnesota states, and corn and potato (Solanum tuberosum), respectively. The application of anhydrous NH₃ had the highest value of CN₂O loss, and ammonium nitrate had the highest CNO₃⁻ loss. Among the different placement methods, the injection of fertilizer-N had the highest CN₂O loss, whereas the banding of fertilizer-N had the highest CNO₃⁻ loss. The maximum CNO₃⁻ loss was higher for chisel than no-tillage practice. Both CN₂O and CNO₃⁻ were positively correlated with fertilizer N application rate and the amount of water input (irrigation and rainfall). Fertilizer-N management strategies to control N loss should consider the spatio-temporal variability of interactions among climate, crop-and soil types. Full article