MODIFICATION AND APPLICATION OF THE SWAT MODEL TO SIMULATION CROP GROWTH IN ZHUOZHANG RIVER BASIN

SWAT adopts EPIC model to simulate crop growth, without considering different sensibility for water deficit in each crop growth stages. This research modified calculation method of crop yield, on the basis of SWAT model considering temperature as one of the most important factors of controlling crop growth. Based on the source model calculating potential yield, the formula set phase relative evapotranspiration as variable and this method divided the growth stage through the fraction of accumulated heat units for considering different sensibility for water deficit on each stage. The modified SWAT model was simulated in Zhuozhang River Basin. The determination coefficient R-2 and Nash-Sutcliffe coefficient Ens of ET data from 2003 to 2004 were 0.88 and 0.87 respectively. The simulation yield followed a similar trend as the actual yield and showed high determination coefficient R2 and Nash-Sutcliffe coefficient Ens values.