Effect of elemental sulfur application on ammonia volatilization from surface applied urea fertilizer to calcareous sandy soils

Widespread acceptance of urea was delayed in part due to its greater potential for nitrogen (N) loss via ammonia volatilization. Elemental sulfur (S⁰) at rates of 0, 1, 5 and 10 t ha^-1 combined with or without urea and inoculation of Paracoccus versutus (Pv) were tested to determine NH₃-N volatilization from urea in sandy calcareous soils of Masafi-1 and Masafi-2. Daily NH3-N loss was measured up to 29 days after surface urea application in both soils using the closed dynamic airflow system. Total NH₃-N volatilizations from urea-treated soils were 22.15 to 29.74 % of applied N in Masafi -1 and Masafi -2 soils, respectively. Application of S⁰ had a positive influence on reducing NH₃-N volatilization from surface applied urea. In both soils significant reductions in NH3-N volatilization were observed in amended soil by S⁰. The result reveals that S⁰ at rates of 1or 5 t ha^-1 and 5 or 10 t ha^-1 is required to minimize volatile loss of NH₃-N from surface applied urea in Masafi-1 and Masafi-2 soils, respectively. Application of Pv with or without S⁰ and urea had no positive influence on reduction of NH3-N volatilization.