Movement and Retention of Phosphate in Lateritic Soil Cores

Core samples of an Oxisol from an upland site of the Bhubaneswar Research Farm collected at three arbitrary depths viz., 4–10, 19–26 and 34–41 cm were employed to study the movement of phosphate ions using a miscible displacement procedure under saturated condition. Phosphate retention and velocity of phosphate solution flowing in soil pores were found to be inversely related in the case of soil cores of comparable physical and chemical properties. On the basis of theoretical analysis of these experimental results, it was concluded that phosphate sorption in this soil is not a first order kinetic process whether or not the soil solution is moving.