Application frequency and abrasive grit type did not influence
end-of-season weed biomass (Table 2). However, a post hoc contrast
of all grit-treated plots compared with the weedy control suggests
that abrasive-weeding reduced total weed biomass in tomato by
69% (F ¼ 16.5; dfn ¼ 1, dfd ¼ 47; p < 0.001) and in pepper by 97%
(F ¼ 5.8; dfn ¼ 1, dfd ¼ 35; p ¼ 0.02), regardless of grit type or
application frequency. Total weed biomass in the weedy control
averaged 315 and 146 g m2 compared with 99 and 73 g m2 in
plots that were treated at least one time with any grit type in tomato
and pepper, respectively. A lack of application frequency effect
on final weed biomass, despite differences in weed density,
may be the result of resource competition and reduced biomass per
weedy individual.