Tc. Mueller, COMPARISON OF PRZM COMPUTER-MODEL PREDICTIONS WITH FIELD LYSIMETER DATA FOR DICHLORPROP AND BENTAZON LEACHING, Journal of environmental science and health. Part A: Environmental science and engineering, 29(6), 1994, pp. 1183-1195
The objective of this project was to optimize the agreement between th
e Pesticide Root Zone Model (PRZM) simulations for two experiments and
then use those input parameters to predict herbicide leaching in a th
ird experiment. The actual numbers and the simulated results all perta
in to lysimeter data which has previously been described. The agreemen
t between hydrology simulation results obtained using PRZM and actual
field data was optimized by (1) altering the initial soil-water conten
t in the soil profile and (2) adjusting the water holding capacity for
each soil horizon by changing the field capacity water content to per
manent wilting point water content relationship. Once hydrology parame
ters were adjusted for best fit, pesticide degradation rates and adsor
ption coefficients were adjusted to maximize agreement between observe
d dichlorprop and bentazon leaching. Good agreement was obtained in hy
drology simulations and bentazon movement, and poor agreement was obta
ined with dichlorprop movement. A ''blind simulation'' was then perfor
med on bentazon movement in Lanna clay and Mellby sand soils, which in
dicated greater water discharge from the Lanna soil, and minimal benta
zon loss (less than 0.015 mg/m(2)) from each soil.