Distribution of Inorganic Phosphorus Fractions in Soils of Bobbili Mandal, Vizianagaram District, Andhra Pradesh

Abstract

An investigation was carried out to estimate the distribution and relative proportion of phosphorus fractions in soils of Bobbili mandal, Vizianagaram district. The soil samples (0-25 cm) from 50 representative locations covering Bobbili mandal were collected and were analysed for the distribution of inorganic phosphorus fractions. Based on elevations and drainage, the study area was divided into three physiographic units viz., uplands, midlands and lowlands. The inorganic phosphorus fractions were in the order of Ca-P > Fe-P > Al-P > saloid-P. Among different phosphorus fractions, the saloid-P, Al-P, Fe-P and Ca-P ranged from 1.25 to 12.50, 1.50 to 45.00, 10.50 to 71.50 and 17.00 to 170.50 mg kg^-1, respectively while the total-P varied from 172 to 752 mg kg^-1. The contribution of saloid-P, Al-P, Fe-P and Ca-P towards total-P ranged from 0.75 to 1.70, 2.55 to 7.31, 6.70 to 10.78 and 11.16 to 25.88 per cent, respectively.