Sequential extraction of different pools of phosphorus in alluvial and acid soils of Uttarakhand

The sequencing and availability of inorganic and organic fractions of phosphorus at different days interval in two soils after the fertilizer (SSP) application was the objective of this investigation. The study helped to obtain the sequence of dominating pool of phosphorus at different days intervals and the rate of release in the soil. This sequential fractionation was used for two native soils i) Alluvial soil and ii) Acidic soil, with 0 to 80 ppm SSP/ 100 gm soil added in a pot experiment and the soil samples were analyzed at different days intervals started from 5 days to 60 days. The result revealed that amount of maximum total P fell in the range from 325.14 to 387.30 mg kg-1 and 284.60 to 330.25 mg kg-1 for alluvial soil and acid soil, respectively up to 30 days. In case of inorganic P fractions under alluvial soil the dominating species were like Ca-P > Fe-P > Al-P >Saloid-P, while under acidic soil the following order Fe-P > Al-P > Ca-P > Saloid-P was observed. These two observations also drew the concentration of organic-P fractions in soil. The work concluded that the availability of dominant phosphorus fraction up to 30 days received the maximum Ca-P concentration in alluvial soil and Fe-P up to 60 days in acidic soils, respectively.