Ammonia Losses by Volatilization from Coastcross Pasture Fertilized with Two Nitrogen Sources

Ammonia Losses by Volatilization from Coastcross Pasture Fertilized with Two Nitrogen Sources

Ammonia losses by volatilization from five rates of urea or ammonium nitrate surfaceapplied to coastcross pasture, grown on a dark red latosol (Hapludox) in São Carlos, SP, Brazil, under tropical altitude climate, were measured. Volatilized ammonia was absorbed in traps placed on soil surface. The mean losses from urea applied after five successive cuttings of the grass were 15, 24, 34, and 40% for N rates of 25, 50, 100 and 200 kg N ha-1 per cutting, respectively.