The Effect of Humic Acid and Urea on the Activity of the Urease Enzyme in Soil Planted with Daughter Potatoes

An experiment was conducted using a randomized block design (CRBD) that is common in factorial studies. Twenty treatments (including the control group) were used in the experiment, with three replicates. One level (4 ml kg −1 soil) of plant extracts (P1, P2, P3, and P4) were added as the initial component. These extracts were garlic cloves, pomegranate pulp and peels, eucalyptus, and myrtle, respectively. As for the second component, we have U1 and U2, which stand for 50 and 100 kg N ha −1 of urea fertilizer, respectively. The third component is humic acid, denoted by the symbol (H), added at a concentration of 80 kg ha −1 ; the experimental outcomes were: The urease enzyme’s effectiveness was greatly affected by the fertilizers that were added. For example, humic acid (H) had 66.35 and 61.30 µg N-NH4 + g −1 soil 2h −1 of effectiveness in the two stages, respectively, while the comparison treatment (C) had the lowest effectiveness at 58.38 and 53.26. In the flowering and full maturity stages, the treatment (2U) had the highest average urease enzyme activity, reaching (85.60 and 78.48) µg N-NH 4 + g −1 soil2h −1 , respectively. In comparison, the comparison treatment (C) had the lowest effectiveness, at (58.38 and 53.26) µg N-NH 4 + g −1 soil 2h, respectively. In comparison to the comparison treatment (C), which had the lowest effectiveness at (58.38 and 53.26) µg N-NH 4 + g −1 soil2h for the flowering and full maturity stages, respectively, the combination (P3U1) substantially improved the urease enzyme’s performance, with values of 65.31 and 59.02 µg N-NH 4 + g −1 soil 2h for the two stages.