Book contents
- Frontmatter
- Contents
- Preface
- Part I Farming systems and their biological components
- Part II Physical and chemical environments
- Part III Production processes
- Part IV Resource management
- 12 Soil management
- 13 Strategies and tactics for rainfed agriculture
- 14 Water management in irrigated agriculture
- 15 Energy and labor
- Part V Farming past, present, and future
- Species list
- Conversions and constants useful in crop ecology
- References
- Index
15 - Energy and labor
Published online by Cambridge University Press: 05 June 2012
- Frontmatter
- Contents
- Preface
- Part I Farming systems and their biological components
- Part II Physical and chemical environments
- Part III Production processes
- Part IV Resource management
- 12 Soil management
- 13 Strategies and tactics for rainfed agriculture
- 14 Water management in irrigated agriculture
- 15 Energy and labor
- Part V Farming past, present, and future
- Species list
- Conversions and constants useful in crop ecology
- References
- Index
Summary
All human activity requires energy. The inescapable minimum is dietary energy to maintain the population. In earlier times, if each hunter-gatherer could collect around 33 MJ every day for a family unit (man, woman, and two children), then survival was possible. In practice, additional organic materials, mostly non-dietary, were needed for shelter, clothing, and combustion (cooking and warmth).
Agriculture provided a way to secure that supply, and more, with less environmental hazard and less competition from other organisms. The development and maintenance of industrialized cultures is based upon the substitution of energy for labor in mandatory activities of food provision. By success in raising and stabilizing yields, agriculture has supported an increasing population and released an increasing proportion from labor in food production. Greater participation in cultural, leisure, recreational, and scientific activities improves well-being for all and advances human civilization.
The purpose of this chapter is to explain the extent, pattern, and significance of energy use in agriculture so that we might understand how agriculture at various stages of development can respond to changes in the supply and cost of energy and labor.
Sources and utilization of energy
Earth systems capture energy that originates on Earth and beyond. Earth energy comprises a small geothermal heat flux and the essentially “limitless” nuclear energy of matter. Energy captured from outside is dominantly the flux of radiant energy originating in nuclear fusion reactions in the Sun (Section 6.1), and supported by kinetic energy in ocean currents and tides caused by gravitational forces of planetary motion.
- Type
- Chapter
- Information
- Crop EcologyProductivity and Management in Agricultural Systems, pp. 411 - 436Publisher: Cambridge University PressPrint publication year: 2011