to be robust (that is, be able to continue to meet the goals in the face of stresses and fluctuating conditions; to adapt and evolve), be sufficiently productive, use resources efficiently, and balance the four goals. There are, however, often tradeoffs or synergies among the various goals and their related objectives, toward which sustainability is directed.
In the discussions that follow, the scientific evidence surrounding different farming practices or farming systems that illustrate their ability to further each of these four societal goals is discussed. The committee is not suggesting or implying that a farming practice would have to simultaneously accomplish each of these goals to be considered “sustainable.” Rather, it recognizes and expects that combinations of practices used in a system will affect each of the four goals in different and often complicated ways. A sustainable system would balance and meet each of the four goals to a large extent.
Each of the four sustainability goals consists of a large number of more specific objectives that represent different paths toward achievement of the goal. For example, the goal to “satisfy human food, feed, and fiber needs” requires managing farming systems in the aggregate so that there will be enough affordable food and fiber (including for energy production) in the future for all on the globe, although U.S. production would only play a part in overall global production. That goal has a long history and is a fundamental concern of all societies through time and can be summarized with the crucial question: Will there be sufficient agricultural resources in the future?
Achieving that goal will, at a minimum, require sufficient productivity (for example, the sheer volume of outputs produced from a given agricultural activity), farming practices that produce the outputs at a price that consumers can afford, and marketing and distribution systems to ensure that people have ready access to farm products. The concepts of productivity, affordability, and access represent specific objectives that are required to meet the overall goal.
Even relatively simple objectives can quickly become more complex. For example, agricultural productivity over time is influenced by the technologies that are available.