Transformations of Surface-applied Urea in Three Soils of Varying pHK LSahrawatauthorUrea hydrolysis, volatilization of ammonia and nitrification of ammonium were investigated in a Vertisol and two Alfisols. Urea hydrolysis was complete in 1 day and 2 days in the Vertisol (pH 8.35) and one Alfisol (pH 6.20), resp.; in the second Alfisol (pH 4.50), urea hydrolysis was not complete 10 days after urea addition. Volatilization of ammonia was greatest in the Vertisol (14% of added urea-N); in all soils volatilization had peaked by day 2. Nitrification in the soils was positively correlated with pH. The results are discussed.Soil ScienceFertilizer Applications1992Indian Sociely of Soii ScienceArticle