Phosphorus adsorption behaviour of Vertisols derived from different parent materials was studied. Both Langmuir and Freundlich adsorption isotherms gave good fits when native phosphorus pool was also considered while fitting the adsorption isotherms. Vertisols derived from basaltic and limestone have high phosphorus adsorption capacities compared with those of grey shale, granodiorite and granitic-granodiorite parent materials. Mean adsorption maximum values for different pedons may be arranged as: pedon 5 (limestone) > pedon 2 (basalt) > pedon 1 (grey shale) > pedon 3 (granitic-granodiorite) > pedon 4 (granodiorite). Phosphorus adsorption is significantly correlated with clay content.
Phosphorus adsorption, Langmuir/Freundlich adsorption isotherms, Vertisols, parent materials, soil characteristics
