Results showed that 0.50% concentrations of inhibitors with a 1:1 ratio showed better inhibition, the detailed results are presented in the following sections. IU/g soil for Sheikhupura soil with 0.10, 0.25 and 0.50% concentration respectively after 1 stday analysis. 1 st -day results exposed the control (alone urea) showed the greater enzyme activity as compared to A1 combination of inhibitor for all three districts, which indicated that A1 combination of inhibitors significantly reduces the hydrolysis of urea, especially with 0.50% concentration followed by 0.10 and 0.25% concentration.