Effect of Mixed Urease Inhibitors on N Losses From Surface-applied Urea

Abstract

The effect of mixed urease inhibitors on NH3 volatilization from surface-applied urea was studied. The results showed that mixed urease inhibitors could effectively reduce NH3 volatilization. Mixed urease inhibitors of 0.05% N-(n-butyl)thiophosphoric triamide (NBPT) and 0.05% N-(n-propyl) thiophosphoric triamide (NPPT) reduced NH3 volatilization of23.8% or 28.8% compared with the treatments with single NBPT or NPPT. Mixed inhibitors showed more effectiveness on slowing urea hydrolysis and maintaining lower soil NH4+ concentration for a long time than single inhibitor.