Ammonia Volatilization from Putting Greens Foliarly Fertilized by Conventional or Stabilized Urea

Abstract

Low cost, high N content, and favorable handling characteristics of urea fertilizer (46-0-0) make its use common in turfgrass management. While many investigations confirm incomplete recovery of foliarly applied urea-N by turfgrass putting greens, the efficacy of urease-inhibiting additives, calcium-maleicitaconic polymer or N-(n-butyl) thiophosphoric triamide (NBPT), in preventing NH3 volatilization is currently undocumented. Furthermore, NH3 emissions reduce air and water quality. From 2014 to 2015, NH3 volatilization was measured 0 to 24 h following foliar application of conventional or stabilized urea fertilizers to 'Penn G2' creeping bentgrass (Agrostis stolonifera L.) putting greens at a 20 kg ha(-1) N rate in four separate trials. Using a 63% trapping-efficiency flux chamber system under the duration and conditions described, 11.1% of conventional or calcium-maleic-itaconic polymer-amended urea-N was lost as NH3. Alternatively, combined amendment by NBPT and dicyandiamide (DCD) prevented 1.3 to 1.4 kg ha(-1) NH3-N emissions, reducing volatilization loss to only 3.8 to 4.6% of the foliarly applied urea-N.