Fractions of Phosphorus as Influenced by Organic and Inorganic Sources of Nutrients under Different Cropping Systems in Vertisol

A field experiment was conducted at Dry land Research Station, M.A.U., Parbhani. During 2003-04 and 2004-05 in vertisols with application of organics and inorganics sources of nutrients under different cropping system such as soybean-pigeonpea and sorghum-pigeonpea. After these two cycle, as regards to transformation patterns the added phosphorus was found to be converted to various phosphate fractions. Among the different fractions, maximum phosphorus was found in the form of Org-P followed by Ca-P, Rs-P , Fe-P , Al-P, Sal-P and Occl-P. With increasing phosphorus levels there was sizable build up in all phosphorus fractions.