This section is specifically concerned with gaining a better understanding as to the meaning of sustainability in agriculture, which is a maze of complexity and can be open to wide interpretation. Throughout history farmers have striven to maintain the productivity and fertility in their soil [Fagan, 1974]. Over the last twenty years Australian farmers have become increasingly aware of the need to adopt more sustainable agricultural systems and there has been an increased emphasis placed on the term "sustainable agriculture" [Campbell, 1991]. This has coincided with a proliferation of literature and theories on this topic, leading to numerous and often confusing concepts, as well as many contentious interpretations of the meaning of sustainability [UNE, 1992]. It should be noted from the outset that there is no simple definition for sustainability in agriculture, rather there are numerous definitions and paradigms, which are sometimes conflicting [eds Edwards et al. 1990]. The theories presented are therefore only tentative and are subject to the criteria being used to form the definition.

The search for the meaning of sustainability, as previously discussed, is complex to the point where Campbell [1994] believes that a precise definition remains elusive. As stated previously Campbell [1991] holds that most of Australian farming systems are unsustainable by any definition. Roberts [1995] regrets that there is unfortunately no clear definition of sustainability in agriculture. This lack of a precise definition has left a void of uncertainty or confusion, causing wide interpretations of the meaning and use of the term.

The initial problem therefore is to develop an understanding of the meaning of sustainability in agriculture, which has a wide range of perspectives and shades of meaning. According to Campbell [1991]

Roberts defines sustainable agriculture as

Campbell [1994] adds to the debate over sustainability and asks the question, is sustainability concerned with

Conway [1985] takes an inductive and narrower view of sustainability in regard to agroecosystems and recognises it as part of an analytical framework to evaluate performance along with stability, equitability and productivity being considered as the criteria. Campbell [1994] recognises Conway's [1985] narrower definition of sustainability as "the ability of the system to maintain productivity in spite of a major disturbance such as a large stress [eg salinity, indebtedness] or a large perturbation [drought, flood, disease, a new pest]" [Campbell,1994, p.174].