Ammonia Volatilization from Fertilized Turfgrass Stands 1

Nitrogen applied to turfgrass stands can be lost through leaching, denitrification, or ammonia (NH 3 ) volatilization. The purpose of this investigation was to evaluate the effects of N carrier and mode of application on NH 3 volatilization from a Kentucky bluegrass ( Poa pratensis L.) turf growing on an acidic (pH 6.4) Flanagan silt loam (fine, montmorillonitic, mesic Aquic Argiudoll) soil. The NH 3 which volatilized after application of any of several sulfur‐coated ureas (SCU), prilled urea, spray‐applied solubilized urea, and two liquid N products was measured by passing the airstream from microecosystems, in which the treated turfs were growing, through an indicating boric acid solution to trap NH 3 . Ammonia‐N losses after sulfur‐coated urea fertilization ranged from 0.2% of the applied N when the fertilization rate was 98 kg N/ha to 2.3% of the applied N when the fertilization rate was 293 kg N/ha. When prilled urea was applied at a rate of 293 kg N/ha, NH 3 losses averaged 10.3% of the applied N whereas 4.6 and 1.6% of the applied N was lost after turf was fertilized with 49 kg N/ha from spray‐applied solubilized urea and prilled urea, respectively. Ammonia losses from turf treated with liquid N sources ranged from 3.2 to 4.5% of the applied N. The results of this research indicate that ammonia volatilization occurs to a limited extent in turfgrass stands growing on an acidic soil.