4 Agriculture and the Environment
ground is different. This study found that poisonings in Carchi are amongst the
highest recorded in the world – an annual rate of 171 per 100,000 population for
morbidity, and 21 per 100,000 for mortalities. Pesticides were found on family
clothing, on food and in children’s bedding. To illustrate these pathways to local
people, the researchers added fluorescent dyes to pesticides, and then used UV
lights to show their presence. The challenge, now, is to develop new ways of learn-
ing about pests and diseases in such rural communities, as well as to develop agri-
cultural practices that reduce dependency on those pesticides that are harmful to
humans and the environment.
Although some pesticides are known to be harmful to people, there are surpris-
ingly few empirical studies that analyse their effects. At the global level, the World
Health Organization (WHO) can only estimate very broadly the number of farm-
ers, families and consumers who might be affected. This paper by Francesca Man-
cini and colleagues makes an important contribution to knowledge by conducting
a season long assessment of acute pesticide poisoning in three villages of Andhra
Pradesh in India. An average of 20 pesticide applications are made per season on
cotton. Some 323 adverse events were reported amongst both men (who apply the
pesticides in the fields) and women (who mix products and refill spray tanks).
More than 80 per cent of the events were associated with signs of mild to severe
poisoning; and 10 per cent of pesticide application sessions caused three or more
neurotoxic symptoms associated with organophosphate products. Although 6 per
cent of the spray sessions caused severe neurotoxic effects, no farmers or workers
sought medical care. Low income, marginal farmers were more often subjected to
severe poisoning than landlords. The paper concludes by indicating that Integrated
Pest Management (IPM) methods that reduce the health burden on local people
should be pursued.
Part 2: Agroecology and Sustainability
Agroecosystems are ecological systems modified by humans to produce food, fibre
or other agricultural products. This classic paper by Gordon Conway discusses the
boundaries and components of agroecosystems, which can be regarded as true
cybernetic systems whose goal is increased social value. Agroecosystems exist in a
hierarchy from plant-environment to field, farming system, watershed and so on,
and systems theory indicates that the behaviour of higher level systems cannot
readily be discovered from a study of lower systems, and vice versa. This paper
makes a significant contribution by indicating that agroecosystems have four key
properties: productivity, stability, sustainability and equitability. Agricultural
development inevitably involves making trade-offs between these properties. The
four properties are linked to one another, both within an agroecosystem and between
agroecosystems at different levels in a hierarchy. The trade-offs can be seen clearly in
the history of agriculture, and this paper describes four key examples: the origins of