Assessing Nitrate Leaching With GLEAMS Model in an Agricultural Small Catchment in Southeast China

GLEAMS model was introduced to calculation of nitrate leaching in an agricultural small catchment in Southeast China.Field experiments were carried out in farmlands under different land uses,such as paddy, banana,and vegetable cultivation,at Wuchuan catchment,Fujian Province.Lysimeters were set up in 8 plots different in land use to monitor nitrate leaching from April to December in 2002.After calibration and validation,the model displayed an acceptable performance in simulating nitrate leaching in all plots,except for the plot of paddy field.Results of the simulations show that nitrate leaching in the catchment varied from 4.64 to 38.39 kg·hm^-2 with land uses.Sugarcane,banana and vegetable fields had maximum nitrate leaching and peaked in July and August.Rainfall,land uses and management were significant factors influencing nitrate leaching in the catchment.The model simulations can be used to specifically establish best management practices for nutrient management and pollution mitigation in the catchment.