Bryan G. Hopkins1
Fertile soil is the foundation for food production and successful civilizations and is developed and maintained through the addition of nutrients lost through harvest. Nitrogen (N) accounts for approximately half of global fertilizer inputs. However, N recovery by plants is inherently inefficient with uptake of applied fertilizer N less than most other nutrients. Losses from the soil system can cause negative air and water resource impacts. Additionally, poor fertilizer efficiency is a waste of natural resources and potentially reduces yields, crop quality, and grower profits. Nitrogen-use efficiency (NUE) is increased through using optimal source, rate, timing, and placement. Polymer coated urea (PCU) is a source of N fertilizer that, when correctly managed, can result in virtually no N loss beyond background levels. A summary of our laboratory, glasshouse, and field research trials shows significantly less N loss from soil to the air and water due to dramatic increases in NUE from PCU compared to uncoated urea. Average ammonia volatilization and nitrous oxide emissions were lower for PUC by 300 and 120%, respectively. Residual nitrate was 38% lower for PCU compared to uncoated urea. The N losses for PCU fertilized plants were at or nearly the same as background levels for the controls. In all cases, PCU resulted in crop yields and/or quality which were significantly improved or at least equivalent to uncoated urea when managed properly. The global use of PCU is warranted to greatly improve environmental quality and to meet the demands for providing food, fuel, and fiber for the seven billion plus people on earth.