The fixation of phushates by soils is one of the interesting problems of major importance in the realm of colloidal chenistry of soils. It was formerly believed that the fixation of phosphate in soils is a simple chemical reaction (chemical theory).The phos-phatea may be roasted with hydrated sesquioxides or with caleium carbonate in soils.Ghani(6) was able to show that the power of phosphate fixation of aeid soils could be considerably reduced by deactivating iron and alnminun oxides in the soil with 8-hydrosyl qninoline.