na INLIS000000000002730 Ind 0010-1118002730 A comparison of the isotope recovery and difference methods for determining nitrogen fertilizer efficiency HARMSEN, K. K. Harmsen and J.T. Moraghan. Br.631.84HARc Repr. from : Plant Soil, 105(1988):55-67. 631.84 NITROGEN FERTILIZERS RADIOISOTOPES 1330/MS/88