Weed management: the broader context - Ecological Management of Agricultural Weeds - page 495

If ecological weed management is effective, why do
farmers rely heavily on herbicides?
Although we have argued throughout this topic that ecological weed
management can be effective at reducing weed density, growth, and damage
to crops, some of the procedures discussed are probably not economically
competitive with the cheaper herbicides within the context of the present
world economy. Several factors strongly reinforce reliance on herbicides for
weed control and reduce the likelihood that farmers will adopt ecologically
based alternatives: (i) the apparent ease and low risk of chemical weed man-
agement; (ii) the aggressive marketing of chemical solutions to weed manage-
ment problems, coupled with a lack of widely available information
concerning alternatives; (iii) the externalization of environmental and human
health costs of agrichemical technologies; (iv) the increasing prevalence of
large-scale industrial farms; and (v) government policies that foster input-
intensive agricultural practices.
The apparent ease and low risk of chemical farming
Chemical management of weeds offers apparent convenience.
Applying chemicals with a large boom sprayer is one of the fastest of all field
operations, and applying chemicals from an airplane requires even less of a
farmer's time because such work is generally done by an outside contractor.
Comparisons of conventional farming systems with low-purchased-input or
organic systems generally show lower labor requirements per hectare for con-
ventional farming (Karlen, Duffy & Colvin, 1995; Lighthall, 1996: Hanson,
Lichtenberg & Peters,1997).Moreover,the level of management skill required
to apply herbicides is low relative to the skill required for ecological manage-
ment of weeds. With herbicides, the instructions come on the label. In con-
trast,ecological farming requires adaptation of diverse sources of information
to the local environment of the farm through ongoing observation and
experimentation.
In actual practice, however, the farmer only realizes part of the promised
labor savings.Use of chemicals essentially makes pest management,including
the management of weeds, a largely off-farm activity (Smith, 1992).
Consequently, most of the economic returns for chemical pest management
go to input suppliers rather than to the farmer. The same studies that show
labor savings with chemical farming also frequently show greater net returns
per hectare for ecological management (Karlen,Duffy & Colvin,1995; Smolik,
Dobbs & Rickerl, 1995; Hanson, Lichtenberg & Peters, 1997). Depending on