Degradation of N-(n-butyl) Thiophosphoric Triamide (NBPT) with and without Nitrification Inhibitor in Soils

Recent studies have shown that nitrification inhibitor (NI) impairs the efficacy of urease inhibitor, N-(n-butyl) thiophosphoric triamide (NBPT), in reducing ammonia volatilization and urea hydrolysis rate. A laboratory study was conducted to evaluate influence NI (specifically 3,4-dimethyl pyrazole phosphate) on degradation NBPT six soils. Soils were amended with either (10 mg kg−1 soil) or plus (DI; 10 + 2.5 soil), incubated at 21 °C, destructively sampled eight times during a 14-day incubation period. The soil quantified by measuring concentration high-performance liquid chromatography-mass spectrometry, rate constant modeled an exponential decay function. showed persistence not influenced presence NI, as across soils 0.5 d−1 DI. In contrast, significantly dependent soils, values ranging from 0.4 1.7 d−1. Soil pH most important variable affecting half-life d acidic 1.3 2.1 neutral alkaline faster may explain its reduced such