Abstract
Urea is the most commonly used nitrogen fertilizer to supply nitrogen (N) to plants. However, when applied on the soil surface, urea is hydrolyzed by the urease enzyme and lost by ammonia (NH3-N) volatilization, causing environmental, economic and human health problems. The N-N-(n-butyl) thiophosphoric triamide (NBPT) urease inhibitor is widely used to reduce NH3-N losses, but gains in yi…