Nitrogen source affected weed biomass in all years
(Po0:05). The unfertilized control was among treat-ments with the lowest weed biomass (Table 4), indicat-ing that weed growth responded positively to higher soil
N levels. Similar to weed density results, weed biomass
was often less with banded N than with broadcast N
fertilizer. Rasmussen (1995)similarly reported that B.
tectorum biomass was lower with banded than with
surface broadcast N fertilizer. Contrary to our findings,
Cochran et al. (1990)found that B. tectorumbiomass
was usually similar with banded and broadcast N
fertilizer