Fertilizer Phosphorus in Fractions of Soil Phosphorus

An investigation to study the fixation and distribution of different phosphatic fertilizers, in various froms of soil phosphorus, was carried out. For this study three soils with varying amounts of calcium carbonate and of different pH were selected. It was found that over 80 per cent of the added phosphorus was retained by these soils. In the soil having more CaCO₃ most of the retained phosphorus was bound to calcium irrespective of the nature fertilizer, whereas it was predominantly bound to aluminium and iron in the case of the soil having little CaCO₃. The behaviour of the soil with intermediate amount of CaCO₃ was midway between the two.