Regulation of nitrification by benzotriazole, o-nitrophenol, m-nitroaniline and dicyandiamide and pattern of NH3 emissions from citronella field fertilized with urea

Nitrification inhibitors are useful for reducing fertilizer related environ mental pollution. Use of such nitrification inhibitors as, benzotriazole, o -nitrophenol, m-nitroaniline and dicyandiamide has effectively regulated ni trification in a citronella (Cymbopogon winterianus Jowitt.) field fertiliz ed with urea. At 450 kg N ha(-1) yr(-1), there was substantially higher acc umulation of NH4+-N in the soil. Proper placement (5 cm below soil surface) of fertilizers have minimized NH3 emissions even from nitrification inhibi tor treated urea plots. Thus, the nitrification inhibitors can potentially reduce environmental pollution connected to NO3- in soil while maintaining low NH3 gas emissions, if the fertilizer is properly placed.