Emergence of Research on Agro-Ecosystems

Abstract

Ecosystem research using a systems approach has been under way in ecology for about fifteen years, mostly as studies of energy flow and nutrient dynamics. During this time the methods of ecosystem analysis have been applied to a few lightly managed natural resource systems such as fisheries, forestry, and rangelands (30). Systems methods have been applied in agriculture for about the same length of time, but usually in relation to reducing costs, improving marketability, or broadening income options. Agricultural ecosystems are more complex than other natural resource systems in many ways ( ll), and it is understandable that an ecosystem viewpoint has not developed. In addition to the cycling of energy and materials in the agricultural system, there are many man-manipulated processes going on, mostly modifying inputs and exports, but also affecting rate relationships within the system. These interventions are largely the result of economic and market processes, and, ulti­ mately, they control the dominant characteristics of the systems. Although humans can be viewed as a natural constituent of the system, the study of agricultural ecosystems cannot focus on marketing and decision-making processes alone, nor on energy exchange and related ecosystem processes. The economic system governing the intensity of inputs and exports, and the economic viability (survival) of the farm operator determining the inputs are essential, integral components of the agriCUl­ tural ecosystem. Thus, students of agricultural ecosystems must recognize that we are only beginning the long process of molding diverse viewpoints together as a coherent field of inquiry. For convenience, the generic term for the Object of study has become agro-ecosystems. This paper reviews the recent development of an interfacing among the sciences involved and the emergence of an art and science of agro-ecosystem analysis. For the purposes of the review, ecosystems are defined as functioning units of the biosphere, usually self-maintaining (often with perturbations), and deriving distinc­ tive properties from their structural components as well as from interactions among