Journal of the Indian Society of Soil Science

SCOPUS
  • Year: 1996
  • Volume: 44
  • Issue: 3

Phosphorus Adsorption, Desorption and Availability in Alfisols of Varying Agroclimatic Regions

  • Author:
  • B. Ravinder Singh, S.K. Das, K.L. Sharma, B.R.C. Prasada Rao, K. Srinivas, M. Narayana Reddy
  • Total Page Count: 6
  • DOI:
  • Page Number: 381 to 386

Central Research Institute for Dryland Agriculture, Hyderabad, Andhra Pradesh, 500059.

* Present addresses: * B1-F4, 16-9-380/133, APHB Colony, Old Malakpet, Hyderabad, A.P., 500036.

Abstract

A few Alfisols and related soils from arid, semi-arid and sub-humid climatic regions of India varying in texture, organic carbon, CaCO3, DTPA-Fe and exchangeable Al contents were analysed for phosphorus using different extractants. Of the P extracted by various extractants, the water extractable P (r = 0.70*), Olsen's P (r = 0.66*), Kumar's extractant P (r = 0.70*) and P extracted by Soltanpur and Schwab's method (r = 0.70*) correlated with saloid bound P which was the important source of plant available P in soil. Phosphorus adsorbed at 0.2 mg VI equilibrium solution concentration of P in these soils ranged from very low (9 mg kg−1 soil) in semi-arid soil to medium (144 mg kg−1 soil) in sub-humid soil. A substantial part (42–60 per cent) of added P was desorbed during two successive desorptions with 0.5M NaHCO3 (pH 8.5). The first desorption released considerably more P than the second. The adsorption data significantly fitted to modified Freundlich, Freundlich and Langmuir equations. Correlation studies indicated a close relationship between P adsorption and DTPA-extractable Fe (r = 0.88**), organiccarbon(r = 0.88**), clay(r = 0.72*)and CaCO3 content(r = 0.76*) in the soils suggesting the important role played by these constituents in P sorption phenomena.

Keywords

Adsorption, agro-ecoregion, A/fisol, desorption, phosphorus extractants and availability