02029naa a2200313 a 450000100080000000500110000800800410001910000180006024500860007826000090016430000150017352010810018865000150126965000130128465000190129765000130131665000270132965000120135665000110136865000200137965000160139965000110141565000300142665000170145670000150147370000180148870000130150677301960151915454051999-07-16       1999    bl uuuu     u00u1 u    #d1 aWESTERHOF, R.  aLabile N and the nitrogen management index of oxissols in the Brazilian cerrados.  c1999  ap.133-140.  aThe effect of land use on the availability of soil nitrogen (N) was studied by separating total soil N into one labile and one stable fraction by oxidation and extraction of labile N with potassium permanganate. The nitrogen management index (NMI) was calculated according to Blair et al. (1995) for the carbon management index. In all systems, labile N released by potassium permanganate was a better indicator for nitrogen availability than were total and stable N. The NMI was a good indicator for N availability but gave no information on the total amount of N. In land-use systems analysis, total N and labile can be used together as a simple and rapid way to evaluate the nitrogen status of the soil. Legume-based pastures specifically increased the amount of labile N. Although soybeans had a dominant role in the continuous cropping systems studied, total N contents decreased, compared with native savanna. The availability of N under legume-based pastures and legume-based pastures/crop rotations was higher than under native savanna and continuous cropping systems.  aFerralsols  aland use  amineralization  anitrogen  apotassium permanganate  aCerrado  aManejo  aMineralização  aNitrogênio  aOxisol  aPermanganato de Potássio  aUso da Terra1 aVILELA, L.1 aAYARZA, M. A.1 aZECH, W.  tIn: THOMAS, R.; AYARZA, M.A., ed. Sustainable land management for the oxisols of the Latin American savannas: dynamics of soil organic matter and indicators of soil quality. Cali: CIAT, 1999.