Kinetics and thermodynamics of urea hydrolysis in the presence of urease and nitrification inhibitors

Urease inhibitor [N-(n-butyl) thiophosphoric triamide (NBPT)] and nitrification (NI) (3,4-dimethylpyrazole phosphate) have been used to reduce nitrogen (N) losses from urea-based fertilizers. This study evaluated the effect of temperature, NBPT, NI on kinetic thermodynamic properties urea hydrolysis in six soils. Soils were amended (250 kg N·ha ?1 ) with (UR), NBPT treated (UR ), or + DI incubated at 5, 15, 25 °C, destructively sampled eight times during an 18 d incubation. We measured rate by disappearance time determined constant (k; assuming first-order kinetics. Our results showed that k increased temperature order 0.07 (5 °C), 0.12 (15 0.20 (25 °C) across soils treatments. In addition, declined UR (0.19) > (0.11) (0.08) temperatures. Although urease inhibitor, half-life 3.8 8.3 soil–temperature, addition a significantly reduced approximately 2 soil–temperature. Thermodynamics parameters was nonspontaneous, enthalpy entropy changes not different among treatments five conclude often-reported greater ammonia volatilization than may only be due persistence ammonium presence but also because inhibitory hydrolysis.