USE OF SOIL THIN-LAYER CHROMATOGRAPHY TO ASSESS THE MOBILITY OF THE PHOSPHORIC TRIAMIDE UREASE INHIBITORS AND UREA IN SOIL

The effectiveness of a urease inhibitor will be improved in upland soi ls if it is not separated from urea due to differential rates of diffu sion in soil. Soil thin-layer chromatography (TLC) was used in experim ents conducted on five soils to determine the mobility of urea in soil relative to the mobility of four phosphoric triamide urease inhibitor s (N-[n-butyl] thiophosphoric triamide, nBTPT; cyclohexyl thiophosphor ic triamide, CHTPT; N-[n-butyl] phosphoric triamide, nBPT; and cyclohe xyl phosphoric triamide, CHPT). The CHPT and nBPT inhibitors and urea moved as compact spots as similar rates. The front of the nBTPT spot m oved the same distance as the urea though it showed significant traili ng. The CHTPT inhibitor was immobile in all soils. The nBTPT inhibitor was shown to undergo partial conversion to nBTP during its elution on the soil TLC plates.