Weed management: the broader context - Ecological Management of Agricultural Weeds - page 502

surface and ground water contamination? In the long run, depletion of non-
renewable resources,particularly petroleum,and cumulative damage to ecosys-
tems and human health by resource degradation and pollution are likely to
precipitate substantial changes in the nature of economic activity (Brown,
Flavin & Postel,1991; Hawken,1993; Daly & Cobb,1994).Under optimistic sce-
narios, the need for restoring balance between human economic activity and
ecosystem processes will provide incentives for agriculture, industry, and
government to move toward an economy that fosters sustainable agricultural
systems. At that point, ecological weed management will present a feasible
option for managing weeds in an efficient, environmentally harmonious
manner.We discuss needed changes in policy in the final section of this chapter.
Feeding a growing human population
Policies favoring industrial agriculture are justified as an antidote to
hunger and malnutrition in a rapidly growing human population and to the
increasing destruction of forest and wetland habitats. Advocates of industrial
farming present herbicides as one of the modern tools necessary to feed the
world and protect the environment (Schneiderman & Carpenter, 1990; Avery,
1995).
If farmers relied on ecologically based weed management strategies and
greatly reduced their use of herbicides, would they produce enough food?
Would more land be required to match the output from conventional
farming, thereby reducing wildlife habitat and further threatening biological
diversity? We believe that the answer to the first question is “yes,”and that the
answer to the second is “no.” Moreover, the second question falsely poses a
dichotomy between agriculture and the natural world.
Food security
Recent studies indicate that intensive use of chemical inputs is not the
only path to increasing the productivity and efficiency of farms.In both indus-
trialized and developing countries, farming systems operated with minimal
use of herbicides, other pesticides, and synthetic fertilizers can produce high
yields if farmers manage ecological processes intelligently (National Research
Council, 1989; Stanhill, 1990; United Nations Development Programme,
1992; Pretty, 1995, pp. 204-37). Pretty (1995, pp. 19, 206) characterized such
systems as “regenerative”and summarized their performance by noting:
(1) “In the industrialized agricultural systems,a transition to sustainable
agriculture could mean a fall in per hectare yields of10 to 20 percent in