Weed management: the broader context - Ecological Management of Agricultural Weeds - page 513

of herbicide active ingredients fell from 3829 Mg during the baseline period
of 1981-85 to 1743 Mg in 1990 (Bellinder, Gummesson & Karlsson, 1994).To
accomplish this reduction, the Swedish government first convened a panel of
scientists to identify ways to decrease herbicide use by 50%,while maintaining
crop yields. Energy requirements for crop production were to be maintained
or reduced. During the period of strategy development, attention was
directed toward cooperation and dialogue among grower groups,agricultural
scientists, environmentalists, and policy makers. The Swedish Farmers
Association actively supported the program and mounted a marketing cam-
paign for “the world's most environmentally friendly agriculture.”
The Swedish government substantially increased research funding, with
emphasis given to improving knowledge of basic weed ecology and nonchem-
ical control methods, increasing crop competitiveness, better understanding
of crop rotation effects on weed dynamics, and developing methods to reduce
weed seed dispersal during crop harvests (Bellinder, Gummesson & Karlsson,
1994).Programs also reduced herbicide use through promotion of surfactants
and better timing of applications. Research on newer low-dose herbicides was
encouraged.
The Swedish extension service was expanded to better deliver information
to farmers. Emphasis was placed on impressing farmers that “less is best.”
Farmers were provided with information about when herbicides and other
pesticides were actually needed to protect crops economically, how applica-
tion rates and frequencies could be reduced, and what alternatives were avail-
able (Bellinder, Gummesson & Karlsson, 1994). Information was developed
for product labels that related herbicide dosage and efficacy to weed popula-
tion densities causing crop yield reductions, rather than to the number of
weeds surviving treatment. Researchers and extensionists demonstrated that
lower rates of herbicides could provide acceptable weed control while increas-
ing cereal yields and profits, due to lower toxicity effects on crops.
Agricultural scientists developed mobile units that helped farmers calibrate
sprayers to improve precision and performance. A government funded grant
program to assist Swedish farmers to convert to organic farming was estab-
lished in 1989 (Matteson, 1995).
Sweden's success in lowering herbicide application on a mass basis (kg ha 1
active ingredients) has been criticized as a “phantom reduction,” since much
of the change resulted from a switch to low-dose products (e.g., sulfonylurea
compounds) and more efficient application technologies (Matteson, 1995).
Adoption of alternative management strategies was limited. Success with
reduced doses may have been possible because previous herbicide use reduced
weed seed banks to low levels (Bellinder, Gummesson & Karlsson, 1994).