factor differences in anova

Hello,

(maybe a quite basic statistical question, but I'm just struggling with
it)

I'm doing an anova:

Res1<-aov(H2O~location+topo+horizon+pF+Error(location:topo:horizon))

(water retention of soils)

which gives a significant difference at factor "location".

Which function should I use to now which locations (there are 3: A, B
and C) differ significantly and which do not?

Thanks,

Wouter