Influence of fertilizers type on the kinetic parameters of the inorganic pyrophosphatase enzyme in a soil planted with maize (Zea mays L.)

An experiment was carried out in one of the fields in the governorate of Al-Diwaniyah to investigate the effects of adding vermicompost, nano-phosphate fertilizer, and humic acid to the rhizosphere during the blossoming and full maturity stages of the maize plant on the kinetic measurements of the inorganic pyrophosphatase enzyme in the rhizosphere (Zea mays L.). A Randomized Complete Block Design was used in the experiment (RCBD). The experiment’s treatments included adding vermicompost fertilizer at a rate of 4 tons h⁻¹, as well as humic acid at rates of 20 and 40 kg h⁻¹, as well as adding nano-phosphate fertilizer at rates of 20 and 40 kg h⁻¹, as well as the addition of nano-phosphate fertilizer at levels (5 and 10 kg h⁻¹) and that symbolized by the symbols (N1 and N2) sequentially, as well as the comparison treatment (with no fertilizer), and the results of the experiment showed the following: The addition of vermicompost led to a decrease in the values of Michalis’ constant for the Inorganic pyrophosphatase in the fully maturity stage, compared to the comparison treatment, which gave the highest mean of Michalis’ constant, while the addition of humic acid at the level h2 achieved the highest maximum velocity in the flowering stage as it reached 197.7 µg PO₄⁻³ -P g⁻¹ soil 5h⁻¹ compared to the control treatment, also the combination Vh1 recorded the lowest value of the Michaelis constant in the fully maturity stage that reaching 0.71 mol compared to the comparison treatment, which recorded the highest mean of the Michaelis constant.