Contenido y formas de fósforo de algunos suelos de la región amazónica del Estado de Maranhao, Brasil

Abstract

Samples of eight series of soils from the Ze Doca Experimental Station Maranhao State Brazil were analyze in its take content and forms of P. using the methods of Mehta et al and Chang and Jackson. These soils derived from cretaceous and quaternary sediments of the Amazonic Region showed a low content of total P. The organic P. contributed with a 73 and 70 per cent of total P for soils and subsoils respectively. Within the inorganic fraction the inert or occluded and reductant soluble phosphates are predominant. The Al, Fe and Ca phosphates contribution is very low. Phosphates soluble in NH1Cl are relatively high assuring a good availability of initial P. To obtain good crops it will be necessary to apply phosphated fertilizers.