N -( n -butyl) thiophosphoric triamide formulation in reducing ammonia volatilization from urea-based fertilizers

摘要

N -( n -Butyl)thiophosphoric triamide (NBPT) has been reported to reduce ammonia volatilization from surface-applied urea and urea ammonium nitrate (UAN). A new NBPT formulation (ARM U?, 18% NBPT) that contains a polymer allowing for lower application rate of NBPT was evaluated for its efficacy relative to Agrotain ? (30% NBPT) and Arborite ? (24% NBPT). Trials consisted of ( i ) a greenhouse study that compared two rates of ARM U-treated urea (360 and 540?mg NBPT kg ?1 urea) with Arborite- or Agrotain-treated urea (480 and 600?mg NBPT kg ?1 urea, respectively) and ( ii ) a field study that compared urea and UAN treated with either ARM U (360?mg NBPT kg ?1 urea) or Agrotain (600?mg NBPT kg ?1 urea) at two sites. Static chambers fitted with acid-charged discs were used to measure ammonia volatilization at six or seven dates over 28?d. In the greenhouse study, ammonia volatilization was reduced by 96% with either ARM U or Agrotain and 95% with Arborite. In the field study, ARM U and Agrotain reduced ammonia volatilization from urea by 80% and 66%, respectively, across sites. Similarly, ammonia volatilization from UAN was reduced by 46% and 60% with ARM U and Agrotain, respectively. Despite the lower NBPT application rates with ARM U, ammonia reduction by ARM U, Agrotain, and Arborite was not significantly different. The addition of ARM U to urea and UAN enabled lower application rate of NBPT without compromising its efficacy.