Nitrate, nitrous oxide, and ammonia loss mitigation with optimum rate of enhanced efficiency nitrogen fertilizer and application timing in corn

Authors: MENEGAZ, SONIA - Proterra Investment; FERNÁNDEZ, FABIÁN - University Of Minnesota; Venterea, Rodney; HELMERS, MATTHEW - Iowa State University; PAGLIARI, PAULO - University Of Minnesota

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 11/21/2024
Publication Date: 3/14/2025
Citation: Menegaz, S., Fernández, F., Venterea, R.T., Helmers, M., Pagliari, P. 2025. Nitrate, nitrous oxide, and ammonia loss mitigation with optimum rate of enhanced efficiency nitrogen fertilizer and application timing in corn. In: Hatano, R. and Baggs, E.M., editors. Nitrogen Cycling and Soil Health. Singapore: Springer. p. 15-38. https://doi.org/10.1007/978-981-96-1132-4.
DOI: https://doi.org/10.1007/978-981-96-1132-4

Interpretive Summary: Nitrate, nitrous oxide, and ammonia are three different forms of nitrogen that can be lost following the application of fertilizer to produce major crops including corn. Each of these chemicals can have negative environmental impacts on water or air quality, but very few field studies have measured all of these chemicals at the same time. In this 3-year study, losses of nitrate, nitrous oxide, and ammonia were measured in a corn production system in Minnesota that was managed using different fertilizer types and application strategies. Applying 100% of the fertilizer at planting was compared to applying 33% at planting and 67% later in the growing season. Also, using conventional urea fertilizer was compared to using a polymer-coated urea designed to release nitrogen more slowly over the growing season. The results showed that the polymer coated urea reduced losses of all three chemicals regardless of weather conditions over the three growing seasons. The strategy using polymer coated urea for 100% of the nitrogen applied at planting also outperformed conventional urea in corn grain yield and produced similar grain yields to the later planting strategies. These results indicate that polymer coated urea may be a viable alternative to meet the need for improved agronomic production and mitigation of N losses to the environment and will be of interest to scientists and land managers aiming to reduce the environmental footprint of agricultural cropping systems.

Technical Abstract: Nitrate (NO3-), nitrous oxide (N2O), and ammonia (NH3) loss in agriculture is a major concern. A 3-yr field experiment was conducted in the US Upper Midwest, in a poorly drained soil under continuous corn (Zea mays L.). The objectives were to evaluate traditional (pre-plant application of urea) and advanced nitrogen (N) management practices (enhanced efficiency fertilizers and split applications) on i) plant N content, corn grain yield and net economic returns; ii) soil N content; and iii) N losses (N2O, NH3, and NO3-). Four treatments evaluated included single pre-plant applications of urea (U) or the polymer coated urea ESN (E), each at 202 kg N ha-1, and pre-plant applications of 67 kg N ha-1 as either urea (U/U+) or ESN (E/U+) followed by 135 kg N ha-1 as urea+NBPT [N-(n-Butyl) thiophosphoric triamide] applied at V6 corn development. Broadcast applications were incorporated by tillage at pre-plant and left on the surface at V6. Treatments E and split produced similar grain yield (mean of 11.1 Mg ha-1) and total nitrogen uptake (TNU) (mean of 157 kg N ha-1) and were greater than treatment U (10.1 Mg ha-1 and 134 kg N ha-1). Although net economic returns decreased in the order of treatment E/U+>U/U+>E>U, the split treatments provided no N loss reduction advantage compared to treatment U. The yearly mean sum of N2O, NH3, and NO3- showed that N loss was 47 to 49% lower with E (14.4 kg ha-1) than U, U/U+ and E/U+ (28.5, 27.1, and 27.5 kg ha-1, respectively). The fact that E reduced N losses for all three pathways regardless of weather conditions, while outperforming U in corn grain yield and producing similar grain yields to the split treatments, indicates that E may be a viable alternative to meet the need for improved agronomic production and mitigation of N loss to the environment.