Distribution of inorganic phosphorus fractions in different phosphorus level soil

Abstract

In Present study, Phosphorus factions in representative agricultural soils belonging to three soil P levels, low-P, medium-P, and high-P, soils collected from Ranga Reddy district, Hyderabad, Telangana. Results revealed that in low phosphorus soil the order of phosphorus fixation is Ca-P>Al-P>Fe-P>Saloid-P with a mean values of 37.32, 11.64, 10.58, 7.58, mg kg-1 and in medium phosphorus soils the order of phosphorus fixation from (M1-M2), Ca-P>Fe-P>Al-P>Saloid-P, (M3-M10) Ca-P>Al-P>Fe-P>Saloid-P with a mean value of 73.27, 30.31, 27.92, 13.55 mg/kg, and in high phosphorus soils showed that the order of phosphorus fixation is Ca-P>Al-P>Fe-P>Saloid-P, with a mean values of 94.53, 34.13, 30.41, 17.08mg/kg. The mean contribution of saloid P to total P was 11.46%, 9.26% and 9.69% in low, medium and high phosphorus status soils respectively. Mean Al- P contribution to total P in low, medium and high phosphorus soils is as follows 17.36%, 20.77% and 19.40%. and The extent of Ca- P contribution to total phosphorus was 55.44%, 50.34% and 53.71% under soil studied.Among all the P fractions, the Al-P and Fe-P fractions contributed very little to the total P compared to the Ca-P. This could be mainly due to the fact that the solubility of Al-P and Fe-P, decreased with increase in pH, forming insoluble iron and aluminium phosphates, resulting in their reduced activity.