S. Zacharias et Cd. Heatwole, EVALUATION OF GLEAMS AND PRZM FOR PREDICTING PESTICIDE LEACHING UNDERFIELD CONDITIONS, Transactions of the ASAE, 37(2), 1994, pp. 439-451
Pesticide simulation models, GLEAMS and PRZM, were evaluated for their
ability to predict pesticide behavior using field data from a plot un
der no-till corn in the Coastal Plain region of Virginia. The models w
ere evaluated in an uncalibrated mode as well as with adjustment of im
portant hydrology parameters. The evaluation of model performance was
based on graphical displays and statistical measures. Difference in ev
apotranspiration (ET) predictions by the two models caused the simulat
ed results from their hydrology components to vary. Runoff and soil mo
isture measured in the field were predicted reasonably well after adju
sting important hydrology parameters. Except for differences in magnit
ude, both models predicted the chemical concentration profiles similar
ly. Overall, GLEAMS represented pesticide behavior in soil better than
PRZM. The models, GLEAMS and PRZM, performed well in predicting pesti
cide mass in the root zone, but were less reliable in predicting pesti
cide concentration distributions in soil. Model predictions of pestici
de fate and transport were not greatly affected by changes in curve nu
mber and the water holding capacity of the soil.