prove sustainability (Gliessman, 1998; Altieri, 2004; Wezel and Soldat, 2009). Agroecology provides a framework to integrate the biophysical sciences and ecology for management of agricultural systems. It emphasizes the interactions among all agroecosystem components (for example, biophysical, technical, and socioeconomic components of the farming system) and recognizes the complex dynamics of ecological processes (Vandermeer, 1995). The approach aims to maintain “a productive agriculture that sustains yields and optimizes the use of local resources while minimizing the negative environmental and socio-economic impacts of technologies” (Altieri, 2000).
When used in agriculture, agroecosystems have been defined as “communities of plants and animals interacting with their physical and chemical environments that have been modified by people to produce food, fiber, fuel, and other products for human consumption and processing” (Altieri, 1995). Agroecosystem design has been recognized as an important part of an agroecological approach, which is a more holistic concept of integrated resource management and understanding complex interactions than a reductionist approach (Swift et al., 1996).
This chapter uses a few farming system types to illustrate how they combine practices and to discuss the potential environmental, social, and economic outcomes. (See Box 2-1 for articulation of the distinction between “farming system”—the integrated system of a single farm management entity—and a “farming system type”—aggregations of farming systems defined by commonalities of commodity, management practices, or farming system approach.) Specifically, the organic, integrated crop–livestock, pasture-based livestock, low-confinement hogs, and perennial grains system types are used in this chapter to represent commonalities of commodity, of specific management approach to those commodities, or of a particular philosophical or scientific approach to farming system management. The integrative perspective of how the components interact with each other in a system and the study of the potential outcomes of those interactions provide valuable information for designing, implementing, and operating a farming system that achieves multiple sustainability goals. Beyond the boundary of a farm, many elements of sustainability, such as product and market diversity and resilience, water resource quality and use, elements of ecosystem health, and community well-being, are highly influenced at landscape, watershed, and regional scales. Sustainability, thus, suggests and requires in most instances an appropriate mix and location of farming system types. The last part of this chapter discusses agricultural sustainability at the landscape level.
The organic approach to farming, and specifically to cropping systems, is of scientific interest as an alternative type of system to the conventional type for several reasons:
The organic approach is driven by a philosophy of using biological processes to achieve high soil quality, control pests, and provide favorable growing environments for productive crops, and by the prohibition of use of most synthetically produced inputs. For farm products to meet organic standards, farmers either substitute “organic” inputs (which are usually expensive) or use “biological structuring” (illustrated by use of practices described below) to achieve a high level of internal ecosystem services in their farming systems to permit high efficiency and productivity. Most productive organic farms are highly integrated and use what is referred to as a holistic approach to manage agricultural operations and their processes and impacts (Vandermeer, 1995; Gliessman, 1998; Altieri, 2004). (See the