Transport behavior of applied chemicals in soil is essential for evaluating their potent ial leaching to groundwater In this study sorption of glyphosate to a sandy. Fluvo aquic soil as affected by pH was determined using batch technique and its transport behavior in the soil as affected by different application rate of phosphate investigated through a miscible displacement experiment under soil water saturated conditions and constant flux. Results show that the glyphosate sorption decreased with increasing pH,particularly when pH rose from 4 to 6 All measured breakthrough curves (BTCs) exhibited different extent of asymmetry with sharp adsorption and slow desorption fronts,the lower the glyphosate application rate,the more distinct the asym metry.Ageneral trend of phosphate application inhibiting transport of the chemical was observed,while the trend was not consis tent with the application rate of phosphate For example,when application rate of glyphosate was 500 mg L^-1,the peak glyphosate concentration in efflux was 459 8 mg L^-1 in Treatment P0,and 147 3 mg L^-1 and 373 6 mg L^-1 respectively in Treat ment P1 and P2. It is probably because application of phosphate leads to decrease in pH and phosphate occupy adsorption sites in the soil preempt ively.