Extension workers are sensing pressure to use soils information and ch
emical characteristics data to guide farmers in selecting pesticides l
east prone to leach into groundwater. Our objective was to estimate di
fferences in herbicide migration to groundwater under conditions typic
al for the Southeast Coastal Plain, and to consider how a farmer might
be advised to use such knowledge in selecting herbicides. We used a s
imple computer code for microcomputers to predict persistence and migr
ation of 17 herbicides through a hypothetical, coarse-textured soil ty
pical of the Southeast Coastal Plain. Appropriate herbicides were sele
cted for several common crop-weed problems, such as sicklepod in soybe
an and Palmer amaranth in com. Groundwater was assumed to be 3.15 m be
low the soil surface. Herbicides selected covered a broad range of hal
f-lives and organic carbon partition coefficients. Only after the firs
t-order degradation rate constant was reduced by a factor of five did
predicted soil water concentrations of several herbicides at the groun
dwater interface reach normal detection limits. Still, predicted conce
ntrations were below the level established for health effects advisory
purposes. Due to the large number of uncertainties and the inability
to estimate practical benefits, we conclude that data relating to soil
and herbicide characteristics cannot be used at this time to override
cost effectiveness, efficacy, and other factors normally considered b
y farmers and Extension professionals in herbicides for weed control.