Since its beginning, agriculture has tested the resiliency of nature. Natural communities have been replaced with artificially supported, productive communities. Agriculture's objectives generally have been to achieve maximum yields, operate with a maximum profit, minimize year-to-year instability in production, and prevent long-term degradation of the productive capacity of the agricultural system (Watt 1973). Theoretically, these objectives should be compatible and mutually reinforcing. Unfortunately, developments in agriculture have removed the crop ecosystems from their parent nonagricultural ecosystems (Potts and Vickerman 1974) to the extent that agroecosystems and natural ecosystems have become strikingly different in structure and function (Table 1). The maintenance of an imposed order of simplified agricultural systems against the natural tendency toward entropy, diversity, and stability demands energy and resources (Turnbull 1969). The depletion of nutrients, loss of soil fertility, and the alteration of soil structure must