Mineral N in Soil and Barley Growth as Influenced by Urease and Nitrification Inhibitors


  • Najlaa Mansour Abed AL-Hleam AL-Essa


Urease, soil, Urea, nitrification inhibitors


Incubation and pot experiments were conducted in two different soils to study the effect of phenyl mercuric acetate (PMA) and dicyandiamide (DCD) and their mixture on urease activity and nitrification rate. Results showed that an application of PMA alone or its combination with DCD gave higher inhibition of urease enzyme which is reflected positively on barley growth and N uptake. However, PMA had no obvious effect on nitrification. On the other hand, DCD could markedly inhibit nitrification of urea-released NH4+ and consequently enhanced plant growth and N uptake over untreated urea, but gave lower than PMA and PMA + DCD treatments.