ABSTRACT
Each region has a unique set of agroecosystems that result from local climate, topography, soil, economic relations, social structure, and history. Each region contains a hierarchy of systems (Figure 2.1) in which the regional system is a complex of land-utilization units with farming subsystems and cropping subsystems which produce and transform primary products, involving a large service sector including urban centers (Hart, 1980). The agroecosystems of a region often include both commercial and local-use agricultural systems that rely on technology to different extents depending on the availability of land, capital, and labor. Some technologies in modern systems aim at efficient land use (reliance on biochemical inputs); others reduce labor (mechanical inputs). In contrast, resource-poor farmers usually adopt low-input technology and labor-intensive practices that optimize production efficiency and recycle scarce resources (Matteson, Altieri, and Gagne, 1984).
