Lehman, Hugh.  Rationality and Ethics in Agriculture
Idaho: 1995
ISBN 0893011797

Page 150

Definition 2 also stipulates that a sustainable production system must be efficient. Efficiency is a matter of degree. A system can be more or less efficient. Further, to speak of efficiency is virtually meaningless unless we are told the respects in which the system should be efficient. Should the system be efficient in the use of land or other natural resources? Should the system be efficient in the use of human labor? Should the system be efficient in the use of energy? Perhaps, the stipulation that the production system be efficient reflects the assumption that resources essential for production are in limited supply. Eventually they will be used up, and at that point in time production would have to be discontinued.

Given this assumption, we can agree that a production system would be sustainable for the longest possible time if it were efficient in its use of essential resources. For this reason, we would agree that a sustainable production system would be efficient in this respect.

However, in contexts of discussions of modern agriculture, the term “efficiency’ normally has other connotations. In my discussions with agricultural scientists who use this term, I get the impression that they regard one system as more efficient than another if the former system yields relatively more income for every unit of costs. In other words, the term “efficiency” when used in discussions of agricultural matters, normally connotes economic efficiency. Further, the time frame over which the system is economically efficient is usually not specified. Now, as he has often been pointed out, a production system can be economically efficient for a period of time while it is rapidly consuming or dissipating resources which are essential for long-term functioning of the system. Thus, an agricultural production system can be both economically efficient and relatively non-sustainable. If the term “efficiency” is understood to mean economic efficiency then, I do not agree that efficiency is essential to sustainability. A sustainable production system could operate in ways that are not economically efficient given
prevailing economic circumstances.