Asian Journal of Plant Sciences1682-39741812-5697Asian Network for Scientific Information10.3923/ajps.2004.529.531SayiliMuratHasan Akca4200434In this study nine statistical models were tested to determine sugarbeet yield response to nitrogen (N) fertilizer application. Statistical analysis indicated that the best model fitted to the data was quadratic model according to different criteria (suitability of the Law of Diminishing Returns, coefficient of determination and standard error of the estimate). In addition, N fertilizer applied by farmers was compared with the amount of fertilizer suggested by experts. It was found out that sugarbeet farms used less (73.99 kg ha^{-1}) and excess (68.91 kg ha^{-1}) N fertilizer. This leaded to loss of yield and money.]]>Cerrato, M.E. and A.M. Blackmer,1990Belanger, G., J.R. Walsh, J.E. Richards, P.H. Milburn and N. Ziadi,2000Paris, Q.,1992Abraham, T.P. and V.Y. Rao,1965Anderson, R.L. and L.A. Nelson,1971Anderson, R.L. and L.A. Nelson,1975Barreto, H.J. and R.L. Westerman,1987Lanzer, E.A. and Q. Paris,1981Altintas, A. and O. Karkacier,2002Akca, H., M. Sayili and K. Esengun,1999Esengun, K., M. Sayili and H. Akca,1999Boehlje, M.D. and V.R. Eidman,1984Guzel, H.A.,1985Nelson, L.A., R.D. Voss and J. Pesek,1985Castle, E.N., M.H. Becker and A.G. Nelson,1987Bayaner, A., A. Erkus and V. Uzunlu,1998Gujarati, D.N.,1995