Agriculture Reference
In-Depth Information
and ecological systems will be seen as the ability to conserve or even enhance the
resource base while meeting the reasonable needs of the people dependent on them.
1.3 sustaInabIlIty
The term sustainable development was coined in the early 1980s and is now the
major subject in development research all over the world (World Commission on
Environment and Development, 1987). Sustainable agriculture has been used to
embody the idea and goals of sustainability in agricultural production.
1.3.1 D e f i in i t i o in s
Agricultural sustainability has been defined and characterized in vastly different
ways (Harrington, 1992). Each of the many definitions is devised from a different
perspective and for a different purpose (Winograd, 1994), and little headway has
been made in the search for a comprehensive and concise definition (Pearce et al.,
1990). The various definitions can be categorized into one or more of three main per-
spectives: the agroecological concept, the resource concept, and the growth concept
(Harrington, 1992).
Definitions with an agroecological perspective focus on sustainability in terms
of system resilience . This is the ability of an agricultural system or ecology to main-
tain its productivity when subject to stress or perturbation (Conway, 1986). In this
sense, sustainability of a system is enhanced through system diversity and increased
efficiency in use and recycling of nutrients and energy (Altieri, 1987). Consequently,
monitoring trends in system diversity and in the internal cycling of nutrients and
energy would be fundamental in an assessment of sustainability (Harrington, 1992).
The second category of definitions places emphasis on stewardship or the proper
care and protection of resources (Barker and Chapman, 1988). According to this per-
spective, the sustainability of agriculture can best be enhanced by slowing economic
development, stabilizing human population levels, and discouraging the exploitation
of natural resources (Barbier and McCracken, 1988; Durning, 1990). According to
this view, measuring sustainability involves an assessment of the quantity and qual-
ity of natural resources available now and in the future.
In the last category are definitions that focus on the need for continued growth in
agricultural productivity while maintaining the quality and quantity of the resources
devoted to agriculture (Technical Advisory Committee, 1987). This requires that
renewable resources be used at a rate lower than that at which they can be regener-
ated, wastes be emitted at a rate lower than that at which they are absorbed by the
environment, and that use of nonrenewable resources be optimized (Barbier and
McCracken, 1988).
Despite the many differing definitions, there are some notions common to all
(Harrington, 1992). One such notion is that measuring sustainability implies drawing
conclusions or stating probabilities about future events. All such forecasts contain
varying degrees of uncertainty. The degree to which sustainability can be measured
depends on the degree of accuracy of predictions about the future. Another idea
common to all concepts of sustainability is that a measure of sustainability is based
on a time frame. However, different time frames apply to different components of
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