Pakistan Journal of Biological Sciences1028-88801812-5735Asian Network for Scientific Information10.3923/pjbs.2000.812.815AbbasiM. K. AdamsW. A. 5200035The recovery of both mineralized and applied N in soil-plant system is low throughout the world. Leaching, denitrification and NH3 volatilization are thought to be the major N loss mechanisms responsible for low N recovery. The aim of this study was to evaluate the effect of nitrification inhibitor nitrapyrin on N transformations, recovery and to prevent formation of -N which could be lost by leaching and denitrification. Intact soil cores were collected from a grassland field, incubated under aerobic conditions at 20°C with 70 percent WFPS. Amendments used were plus or minus and plus or minus nitrapyrin. Nitrapyrin was used as a nitrification inhibitor. The fate of mineralized and added , accumulation of -N and apparent recovery of applied N were examined during the study. In the absence of nitrpyrin, more than 60 percent of the -N initially present was lost within 42 days period. The apparent recovery of applied N decreased significantly and more than 50 percent of applied N being lost from mineral pool. Accumulation of 60 mg -N kg1 soil in the surface 0-2.5 cm layer indicated that nitrification was an active process in the system. Addition of nitrapyrin decreased and delayed the extent of disappearance, inhibited nitrification by approximately 73 percent and improved N recovery by 36 percent.]]>Abbasi, M.K. and W.A. Adams,1998200265277Abbasi, M.K., Z. Shah and W.A. Adams,19971997pp: 47-54pp: 47-54Aulakh, M.S. and Bijay-Singh,199647197212Avery, B.W. and C.L. Bascomb,19741974Ball, D.F.,1964158492Bolton, H., R.E. Wildung and J.L. Smith,199054887891Bremner, J.M. and C.S. Mulvaney,19821982pp: 595-624pp: 595-624Chen, D.L., J.R. Freney, A.R. Mosier and P.M. Chalk, 1994347583Freney, J.R., D.L. Chen, A.R. Mosier, I.J. Rochester, G.A. Constable and P.M. Chalk,1993343744Freney, J.R., C.J. Smith and A.R. Mosier,199232111Garret, M.K.,19931993pp: 121-132pp: 121-132Hadas, A., S. Feigenbaum, A. Feigin and R. Portnoy,198650633639Keeney, D.R. and D.W. Nelson,19821982pp: 643-698pp: 643-698McTaggart, I.P., H. Clayton, J. Parker, L. Swan and K.A. Smith,199725261268Morrison, J., M.V. Jackson and P.E. Sparrow,19801980Munro, J.M.M. and D.A. Davies,197328161170Patra, D.D., M. Anwar, S. Chand and D.V. Singh,199215N applied as urea and ammonium sulphate in opium poppy (Papaver somniferum L.) grown under greenhouse conditions.]]>32327332Rochester, I., G. Constable and P. Saffigna,19962316StatGraphics Manugistics Inc.,1992Van der Meer, H.G.,19821982pp: 61-68pp: 61-68White, D.C.,1985