Addition of Chemical and Natural Urease Inhibitors in Reducing Ammonia and Nitrous Oxide Losses

To examine the reduction of ammonia (NH 3 ) volatilisation, nitrous oxide (N 2 O) emission and production of grain yield in maize from urea fertiliser with the addition of chemical and natural urease inhibitors, a field experiment was conducted for one growing season of maize on sandy soil at Jabatan Pertanian Perak, Malaysia. Four replicates of three treatments: Urea (control), urea coated with thiosulfinate (UThiol) and urea coated with triamida N-(n-butil) tiofosforica, known as NBPT (UNBPT). After fertiliser application, NH 3 volatilisation, N 2 O emission and grain yield were monitored at different timing. The NH 3 volatilisation was determined using the Draeger tube method while N 2 O emission was discovered using the closed chamber technique. UNBPT showed the lowest NH 3 volatilisation as compared with urea, followed by UThiol. For N 2 O emission, there is no significant difference between UNBPT and UThiol but both treatments recorded significant difference with Urea (control). The maize production exhibited a positive significant result by increasing the maize yield in UNBPT and UThiol than Urea (control) treatment. These results suggest that using natural inhibitor may have the most potential to reduce N losses and improve yield nearly as efficiently as chemical inhibitor.