Urea Hydrolysis and Urease Activity in Saudi Arabian Soils

Abstract

Soil samples were collected from eight different localities m Saudi Arabia, and analysed for mechanical properties as well as for urea hydrolysis. The urease enzyme activity of these calcareous soils was also investigated. Urea applied (10 mg urea - N/g soil) was almost totally hydrolysed to ammonia in all soils tested within four weeks. The addition of urea to soils led to a marked increase in the concentration ofNH4 in most soils. The maximum amount ofNH4 was recorded in Alkharj soil (4.0 mg/g soil), a site which exhibited the highest activity of urease enzyme (85 ^g Urea/g/h).