Distribution and forms of phosphorus in the kole soils

Abstract

The different forms of phosphorus, such as saloid-P, Al-P, Fe-P, reductant soluble-P, occluded-P, Ca-P and organic-P, as well as total-P were determined in the surface and subsur face soils collected from 15 locations in the kole land area of Kerala State. The mean values of the different fractions showed that organic-P was the largest fraction, followed in order by Fe-P, reductant soluble-P, Al-P, Ca-P, occluded-P and saloid P. The most abundant inorganic fraction was Fe-P which constituted 29.75% of the total P in the surface layers and 37.46% in the subsurface layers. Reductant soluble-P constituted 23.91% and 22.16% respectively of the total P in the surface and subsurface horizons. Occluded-P formed 1.81% of the total P in the surface soils and 1.50% of the total P in the subsurface soils. Of the total P, 4.15 and 7.09% respectively were found in the Ca-P form in the surface and subsruface layers. The Fe-P was significantly and positively correlated to the total sesquioxides and the Ca-P was significantly and positively correlated with total CaO.