Polymer Coated Urea In Grass Systems: Reduction of N2O Emissions.

Polymer Coated Urea in Grass Systems: Reduction of N₂O Emissions

Nitrogen is an essential plant nutrient in the biosphere but is also a common pollutant in the atmosphere. Following fertilization or natural processes, N may be found as atmospheric nitrous oxide (N₂O), which is a potent greenhouse gas and contributes to ozone depletion. Polymer coated urea (PCU) is one type of N fertilizer which uses temperature-controlled diffusion to control N release to better match plant demand and mitigate environmental losses. Turfgrass is a high value crop that occupies 2% of the total surface area of the United States and receives high rates of N application annually. The objectives of this study were to compare the use of PCU and uncoated urea (urea) and their affects on N environmental losses in cool season turfgrass over the entire PCU N-release period as N₂O. Two field studies were conducted on established turfgrass sites with mixtures of Kentucky bluegrass (Poa pratensis L.) and perennial ryegrass (Lolium perenne L.) in sand and loam soils. Each study compared 0 kg N ha^-1 (control) to 200 kg N ha^-1 applied as either urea or PCU (Duration 45CR®). Application of urea resulted in 127–476% more evolution of measured N₂O into the atmosphere, whereas PCU was similar to background emission levels from the control. Compared to urea, PCU reduced N₂O emissions by 45–73%, while improving growth and verdure compared to the control. This improvement in N management to ameliorate atmospheric losses of N using PCU will contribute to conserving natural resources and mitigating environmental impacts of N fertilization in turfgrass.