126 Agroecology and Sustainability
Equitability
Equitability is defined as the evenness of distribution of the productivity of the
agroecosystem among the human beneficiaries. Once again, the productivity may
be measured in many ways, but, commonly, equitability will refer to the distribu-
tion of the total production of goods and services of the agroecosystem under
consideration, i.e. the field, farm, village or nation. The human beneficiaries may
be the farm household, or the members of a village or a national population.
Equitability may be measured by a Lorenz curve, Gini coefficient or some
other related index (Lorenz, 1905; Gini, 1912; Kuznets, 1955; Theil, 1967; Atkin-
son, 1970, 1975; Gastwirth, 1972; Sen, 1973, 1976; Fields, 1980; Kakwani,
1980). In practice, though, it is difficult to define equitability in a purely positive
sense, the measures available reflecting different value judgements. Equitability is
thus often the evenness of distribution of productivity among the human benefi-
ciaries according to need.
Factors Affecting System Properties
Although the four properties, described above, are the key properties in determin-
ing the social value of an agroecosystem there are a large number of other ways that
can be used to characterize an agroecosystem. Examples include energy and mate-
rials conservation, diversity, autonomy, market penetration and some measure of
cultural acceptability. Each of these, however, can be shown to contribute to social
value through one or more of the four primary properties, in much the same way
as birth rate contributes to the productivity of a population or photosynthesis to
the growth of a plant. Thus materials conservation can contribute to productivity
but also has a major effect on stability and sustainability; diversity contributes to
all four primary properties, although in rather complex ways; and cultural accept-
ability is an important component of sustainability and equitability.
An early step in the analysis of a given agroecosystem is to identify the impor-
tant factors and processes that affect the primary system properties. Table 6.2
shows one such list for the high altitude villages in the Karakoram mountains of
northern Pakistan, produced during an Agroecosystem Analysis workshop (Con-
way et al, 1985).
Agricultural Development
The four properties are linked with each other, both within an agroecosystem and
between agroecosystems at different levels in the hierarchy. However, the linkages
are complex and frequently negative in effect. If we now regard the properties as