AMMONIA VOLATILIZATION FROM UREA AMENDED WITH TRIPLE SUPERPHOSPHATE AND POTASSIUM-CHLORIDE

Ammonia volatilization from urea reduces N fertilizer efficiency of cr ops, Addition of acidic materials to urea may reduce NH3 volatilizatio n and improve N use efficiency, The objectives of this study were to c ompare the effects of compacted or blended mixtures of urea and triple superphosphate (TSP), urea and KCl, or urea, TSP, and KCl on NH3 vola tilization and N use efficiency by corn (Zea mays L.) under a no-till system, A Ste. Rosalie clay (Typic Humaquept) and an Ormstown silty cl ay loam (Typic Humaquept) were used with three rates of TSP (0, 26, an d 52 kg P ha(-1)) and two rates of KCl (0 and 100 kg K ha(-1)). Total NH3 volatilization for 9 d following fertilization ranged from 27 to 3 1 g kg(-1) of added urea-N on the Ste. Rosalie soil and born 50 to 82 g kg(-1) on the Ormstown soil with urea alone. Ammonia volatilization decreased when TSP, KCl, or both were applied with urea. Nitrogen reco very of added urea, N use efficiency, and corn yields increased with a dded TSP and KCl, Compacted mixtures of urea with TSP, KCl or both had an advantage over blended fertilizers in reducing NH3 ovolatilization and improving N use efficiency and corn yields.