Urease activity and kinetics of urea transformation in soils
1984
Kumar, Vinod | Wagenet, R. J.
The effects of soil type, N concentration, organic matter, moisture regime, CaCO3, and temperature on urease activity and kinetics of urea transformation were studied in a series of laboratory incubation experiments. Urease activity ranged from 19.0 to 26.1 tig urea-N hydrolyzed/g soil/h at 37°C. Increase in N levels, temperature up to 35°C, and moisture content, up to field capacity linearly increased urease activity of three selected soils, and addition of CaCO3 up to 8% decreased it considerably. There was no effect of undecomposed grasses, but decomposed organic matter increased soil urease activity. Urea transformation followed first-order kinetics, and the rate of urea hydrolysis increased with temperature in the three soils. Thermodynamic properties (energy of activation, free energy, entropy) were calculated for selected soils.
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