THE SYLLABUS SAYS
Sustainable agriculture
- Examine the concept of sustainable agriculture in terms of energy efficiency ratios and sustainable yields.
- Examine the concept of food miles as an indicator of environmental impact.
KEY TERMS
Input
Output
Yield
Hectare
Energy efficiency ratio
Sustainable yield
Food miles
Output
Yield
Hectare
Energy efficiency ratio
Sustainable yield
Food miles
WHAT IS 'SUSTAINABLE' AGRICULTURE?
Sustainable agriculture is hugely important to humanity. The following video is taken from the UK Guardian website in October 2013:
.Sustainable agriculture is defined by the United Nations Food and Agricultural Organisation (FAO) as
"the management and conservation of the natural resource base, and the orientation of technological and institutional change in such a manner as to ensure the attainment and continued satisfaction of human needs for present and future generations. Such development... conserves land, water, plant and animal genetic resources, is environmentally non-degrading, technically appropriate, economically viable and socially acceptable".
This is a lot to include - so the IB Course Companion (Nagle and Cooke, 201,1 p269) define it as
"the ability of a farm to produce food indefinitely, without causing irreversible damange to ecosystems"
FAO goes on to state that there are 5 key principles of sustainable agriculture:
"the management and conservation of the natural resource base, and the orientation of technological and institutional change in such a manner as to ensure the attainment and continued satisfaction of human needs for present and future generations. Such development... conserves land, water, plant and animal genetic resources, is environmentally non-degrading, technically appropriate, economically viable and socially acceptable".
This is a lot to include - so the IB Course Companion (Nagle and Cooke, 201,1 p269) define it as
"the ability of a farm to produce food indefinitely, without causing irreversible damange to ecosystems"
FAO goes on to state that there are 5 key principles of sustainable agriculture:
- Improving efficiency in the use of resources is crucial to sustainable agriculture
- Sustainability requires direct action to conserve, protect and enhance natural resources
- Agriculture that fails to protect and improve rural livelihoods and social well-being is unsustainable
- Enhanced resilience of people, communities and ecosystems is key to sustainable agriculture
- Sustainable food and agriculture requires responsible and effective governance mechanisms
ENERGY EFFICIENCY RATIOS AND SUSTAINABLE YIELDS
Similar concepts: Ecological footprint and global hectare
These concepts are very similar to those of the 'global hectares' discussed when studying ecological footprint. The definitions below are taken from the glossary page of the Global Footprint Network website:
Ecological Footprint: A measure of how much area of biologically productive land and water an individual, population or activity requires to produce all the resources it consumes and to absorb the waste it generates, using prevailing technology and resource management practices. The Ecological Footprint is usually measured in global hectares. Because trade is global, an individual or country's Footprint includes land or sea from all over the world. Without further specification, Ecological Footprint generally refers to the Ecological Footprint of consumption. Ecological Footprint is often referred to in short form as Footprint. "Ecological Footprint" and "Footprint" are proper nouns and thus should always be capitalized.
Global Hectare (gha): Global hectares are the accounting unit for the Ecological Footprint and biocapacity accounts. These productivity weighted biologically productive hectares allow researchers to report both the biocapacity of the earth or a region and the demand on biocapacity (the Ecological Footprint). A global hectare is a biologically productive hectare with world average biological productivity for a given year. Global hecares are needed because different land types have different productivities. A global hectare of, for example, cropland, would occupy a smaller physical area than the much less biologically productive pasture land, as more pasture would be needed to provide the same biocapacity as one hectare of cropland. Because world productivity varies slightly from year to year, the value of a global hectare may change slightly from year to year.
Sustainable yield
In the same way as the global hectare represents the amount of reproductive capacity of the Earth, the sustainable yield can be understood as the capacity of the agricultural unit to produce the same amount of yield year on year. In other words, sustinable yield is:
"the useful biomass (i.e. food) that can be obtained from a given land area without harming the potential productive capacity of the land and without requiring further inputs"
In other words, it's the amount that the land can produce without harming it's potential to produce the same in the future.
Energy efficiency ratio
The efficient ratio refers to the inputs to a farm compared to the outputs. The most efficient farms have low inputs (e.g. the energy used in producing machinery, transport, fertilizer and so on) compared to the output.
FOOD MILES AS A MEASURE OF ENVIRONMENTAL IMPACT
The IB syllabus (2009 for first examination 2011) defines food miles as: "A measure of the distance that food travels from its source to the consumer. This can be given either in units of actual distance or of energy consumed during transport."
See these two pages on this site for further information:
Food miles (by students)
Food miles in depth (by me!)
See these two pages on this site for further information:
Food miles (by students)
Food miles in depth (by me!)