An analysis is reported of conventional vs. alternative metrics used in measuring food production efficiency. Economic efficiency is driven by marketplace economics, while engineering efficiency is driven by useful energy conservation. As farming systems are optimized for maximum efficiency, how “efficiency” is defined will dictate the methods used in food production. Farming methods that are optimized in terms of economic efficiency have environmental consequences that are not inherent of engineering efficiency; however, farming methods optimized in terms of engineering efficiency have labor requirements not inherent of economic efficiency. A shift from optimizing food production in terms of economic efficiency to engineering efficiency may be necessary in order to feed a growing human population.
With a growing human population, it is becoming increasingly important for potential food Calories (units of energy) to not go to waste. In optimizing food production efficiency, the definition of the metric “efficiency” must reflect a measure that is directly proportional to food availability, as opposed to marketplace economics. There is an opportunity to facilitate the optimization of production in terms of an efficiency metric that is independent of finance: engineering efficiency,
Optimizing food production in terms of engineering efficiency as opposed to economic efficiency will mitigate challenges related to antibiotic resistance and eutrophication. The shift to the
Practical application of the
Livestock production is the focus of this proposal; however, it is the opinion of the author that the same principles of efficiency optimization can be carried over to any crop production.
The farm has inputs and outputs (
In this paper, the example used is of meat production, which for time, money, and energy outputs meat, heat, and manure. The efficiencies analyzed will be optimized in terms of money (economic efficiency) vs. Calories (engineering efficiency). While “money” and “Calories” are not listed as a farm outputs, they do serve as inputs and are therefore appropriate units to use in analyzing efficiency, representing how much useful input can be extracted from a given system’s output.
The definition of “efficient” dictates the measure of a system’s efficiency. Conventionally, produce is maximized while costs (time & money) are minimized,
because farm business optimization is based on marketplace economics. For example, one 1000 lb steer will yield 310 lb beef* valued at approx. $2.30 per lb [
The difference in dollar value between meat and manure as calculated above is displayed in
However, one pound of dry manure contains 8500 Btu (2150 Calories or kcal) [
The difference in caloric value between meat and manure as calculated above is displayed in
Optimizing to maximize meat production does not necessarily correlate to energy reuse maximization. In fact, regardless of how highly economic-efficient a steer is, it will only attain a 5% engineering efficiency§:
On the other hand, the greater percent of manure that is usefully recycled, the higher the engineering efficiency:
Engineering efficiency recognizes the primary producer’s primary function as soil building [
*Assuming fat and bones are removed from a 62% dressing weight.
†Assuming a linear increase in weight from 0 to 1000 lb over a two-year growth period.
‡Assuming semi-solid manure containing 85% moisture [
§Assuming manure Calories equal feed Calories.
Farming methods are determined by optimizing in terms of efficiency. The factory farm is more efficient in terms of
Hoop Barn:
Feedlot:
Higher-value manure introduces economic incentive for its transport onto cropland, avoiding challenges related to on-farm nutrient stockpiling like eutrophication and antibiotic resistance.
Economic-efficient farming methods have environmental consequences. In order to ensure that manure is valued as a nutritious compost, the appropriate metric must be used in optimizing the farming process. If an inappropriate metric is used, farming methods will be optimized without regard to useful recycling of energy outputs, and the value of manure can drop until it becomes a hazard: Public health threats, such as antibiotic-resistant Staphylococcus aureī like MRSA, fecal streptococci and coliforms [
Antibiotic-impregnated feed can be avoided by keeping livestock in healthy pastures with shelter: a low-stress, clean environment where exercise is possible and nutritious diet available [
Engineering-efficient farming methods have relatively high labor requirements. This is the problem at hand: pastured livestock production, however efficient in terms of
Tilling Unit | Required Hours | Machinery Input (kcal) | Petroleum Input (kcal) | Hour/Day | Working Human/Hour Input (kcal) | Human Daily Energy Input (kcal) | Total Human Input (kcal) | Oxen Energy Input (kcal) | Total Input (kcal) |
---|---|---|---|---|---|---|---|---|---|
Human Power | 400 | 6000 | 0 | 10 | 400 | 5400 | 216,000 | 0 | 222,000 |
Oxen (pair) | 65 | 6000 | 0 | 10 | 375 | 5150 | 33,500 | 260,000 | 299,500 |
6-HP Tractor | 25 | 47,500 | 237,600 | 10 | 200 | 3400 | 8500 | 0 | 293,600 |
50-HP Tractor | 4 | 61,300 | 306,300 | 4 | 200 | 3400 | 1360 | 0 | 368,900 |
This consequential trend―labor reduction in the interest of economic efficiency, at the expense of engineering efficiency―may be continuing with more-recent innovations such as solar cells, which present ecological hazards through their mining and manufacture in countries with minimal environmental regulations [
Special thanks to Drs. Gene Pirelli and Lauren Gwin for providing the author with agricultural guidance; Dr. Christy Brekken for advice on refining the ideas written in this paper; and farmers Chris Hansen, Laura Sage, Robin Sage, and Tyler Jones for presenting their personal perspectives as food producers. Also, thanks to nonprofit directors Annette Mills and Tom Kaye for their interest in this work. Finally, thanks to family for unending support.
McGuire, M. (2017) Food Production Engineering Efficiency: A Critical Analysis of the Conventional Metrics Used in Measuring Agricultural Efficiency. Engineering, 9, 427-433. https://doi.org/10.4236/eng.2017.95025