@article{icrisat3974,
           title = {Adsorption and desorption of phosphate in some semi-arid tropical indian vertisols},
       publisher = {Kluwer Academic Publishers},
          author = {S Shailaja and K L Sahrawat},
           pages = {87--96},
            year = {1990},
          volume = {23},
         journal = {Fertilizer Research},
          number = {2},
             url = {http://oar.icrisat.org/3974/},
        abstract = {The P adsorption and desorption characteristics of four Vertisols belonging to three agriculturally important soil series were studied. The amounts of P adsorbed by the soils at 0.2 {\ensuremath{\mu}}g/ml equilibrium solution P concn was low and ranged from 34.3 to 79.5 {\ensuremath{\mu}}g/g soil. The phosphate adsorption was very well described by Langmuir and Freundlich isotherms. The P adsorbed by a Vertisol (BR-1) fertilized with different rates of P in the previous season (0, 10, 20 and 40 kg P/ha) was similar (34.3-41.3) indicating little effect of fertilization on P adsorption. The correlation studies indicated that the DTPA-extractable Fe was the most important factor accounting for P adsorption in these soils and clay and CaCO3 content were relatively less important. The capacity of the two extractants and EUF (electro-ultrafiltration) to desorb the adsorbed P followed the order: EUF (400V, 80?C){\ensuremath{>}} sodium bicarbonate {\ensuremath{>}} EUF (200V, 20?C) {\ensuremath{>}} calcium chloride. The average amounts of P desorbed from the four Vertisols using these methods were 74, 63, 50 and 3\% resp. of the adsorbed P. In the Begamganj soil, the amount of P desorbed by EUF (400V, 80?C) exceeded 100\%, indicating that all of the adsorbed P was desorbable including some native P. The results show that the Vertisols studied have low phosphate adsorption capacity and that the P they adsorbed is easily desorbable}
}