Effect of Coating Urea with Some Plant Secondary Products “Phenolic and Votilized Oils” on Urease Inhibition in Soil

AbdulMehdi Al-Ansari, Mohsen Nasseh Hoshan


An experiment was conducted to study the efficiency of coating urea with some secondary metabolism products extracted from plants to inhibit urease enzyme activity in silty loam soil. Phenolic substances and votilized oils were extrected from data palm fiber, eucalyptus leaves and myrtus leaves by applying standard methods.Urea fertilizer was coated with above extracts at ratios: 2.5, 5 and 10% (w/w) .Coated urea was applied to soils at rates of 30,90 and 270 mgN Kg-1soil.Fifty grames of soil were treated with coated urea and incubated at temperature of 37ᴼ C for 5 and 10 days.Then urease enzyme activity was measured and inhibition percentages were calculated. Results showed that coating urea fertilizer with phenolic or votilized oil compouned extracted from data palm fiber, eucalyptus and myrtus leaves reduced urease activity in soil. Highest urease inhibition (avg 63 % ) was obtained in soil treated with urea coated with phenole compouned (at ratio 5%)or votilized oil (at ratio 10%) extracted from eucalyptus leaves at 270 mg N Kg-1soil. Highest urease inhibition in soil treated with urea + ATS (Ammonium thiosulfate) at 270 mg N Kg-1soil was 56% . These results suggested a possibility of using urea coated with Phenolic substances and votilized oils extracted from some plants to reduced urea hydrolysis in soil and could be apotent substitute for ATS to increase urea efficiency.


Urease inhibitor, Phenolic substances, votilized oils, ATS, Coated urea, Nitrogen.

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