A six-year study on site-specific weed control is presented in this paper.
Weed seedling distribution was assessed and mapped prior to and after post-
emergence herbicide application in four fields planted with maize, sugar be
ets, winter wheat and winter barley, rotating on one site. Herbicides and o
ther weed control strategies were applied site-specifically according to th
e spatial variation of weed populations. Different decision algorithms were
used for chemical weed control methods in each crop. It was found that wee
d distribution was heterogeneous in all years and crops. The crop rotation
before the study was started and during the experiments were conducted had
a strong effect on the spatial and temporal dynamics of weed populations. T
he efficacy of common herbicide application was acceptable in areas with lo
w and moderate weed infestation levels. Within the patches of Poa annua L.,
Alopecurus myosuroides Muds., Chenopodium album L. and Polygonum aviculare
L. more intensive weed control strategies were needed to achieve acceptabl
e weed control levels. These strategies included chemical and mechanical we
ed control practices, cover crops and hand weeding.