Sustainability Interdependance Key Area 1 a Food Supply

Sustainability & Interdependance Key Area 1 a Food Supply

Food Supply

Learning Intentions By the end of this topic you should be able to: State that the human population is increasing. State that there is concern about the ability of human populations to access food of sufficient quality and quantity. Explain why food production must be sustainable. Explain why food production must not degrade the natural resources on which agriculture depends. Define a cultivar (cultivated variety) as a plant or group of plants selected for desirable characteristics and easily propagated. Explain how plant breeders have developed plants with resistance to pests and diseases. Explain why livestock produce less food per unit area than plant crops in terms of loss of energy. State that there are fewer energy losses in food chains that have fewer trophic levels.

Food Security The human population in currently growing. The present human population is: http: //www. census. gov/popclock/ Food security is the ability of human populations to access food of sufficient quality and quantity

United Nations estimate of how the human population could increase Feeding over 7 billion people requires a sufficient and sustainable supply of food. This makes food security a massively important subject for the future of the human race.

Food security is defined as: Access (both physical and economical) to food of adequate quantity and quality by human beings This can refer to a small group (eg household) or a large group (eg country)

Food security Sufficient food must be available at all times Quantity Quality Food security Access Food is sufficiently nutritious and varied to provide a balanced diet People have economic means to obtain the available food

Aspect of food security Note Availability Existence of food in sufficient quantities and of appropriate quality Sufficient economic and infrastructure resources to access available food resources Accessibility Usage Level of nutritional knowledge needed to use food resources properly Sustainability Degree to which food security can be guaranteed over extended time periods

Sustainability With an ever increasing human population, the ‘green revolution’ (1960 s) of producing food depended on the heavy use of fertilisers, pesticides, intensive crop farming…which all eventually lead to a degradation of the environment (land water supply).

Sustainability Newer methods are required to make food production more sustainable without degrading the natural resources on which agriculture depends: • • Increased plant productivity Manipulation of genetic diversity

Improving yields As the area of land suitable for growing crops is limited, increased food production will depend on factors that control photosynthesis and plant growth: 1. Add minerals (fertiliser) or water (irrigation systems) to remove factors which may be limiting plant growth. 2. Replace existing strains of crops with a higher-yielding cultivar (cultured variety). 3. Protect crops from pests (e. g. insects), diseases (e. g. fungi), and competition (from weeds) by using pesticides, fungicides and herbicides. 4. Develop pest-resistant crop plants.

Pests Competition Weeds or too dense planting will slow growth Decrease yield, either by feeding on crops or by making the plant less healthy Food Production Breeding higher yield cultivars Will increase yield, but some require more intensive farming methods and are more dependent on particular soil profiles and nutrients Disease Decrease yield as the plant is less healthy. May also produce food that is unsuitable for eating Soil nutrients Soil profile The depth of soil / drainage etc will determine what type of crop you can grow Plants need specific nutrient profiles. Some may need to be added using fertlisers. Can also use crop rotations

Agricultural production Cereals Maize Legumes Root crops Rice Soya bean Potato Cassava The earth possesses 75, 000 edible plant species, yet we depend on a few to produce 95% of what we eat.

Improving yields All food production is ultimately dependent on photosynthesis. Examples of crops used for food include cereals, potato, roots and legumes. • • Breeders seek to develop crops with: Higher nutritional value Resistance to pests and disease Physical characteristics suitable to rearing and harvesting The ability to thrive in particular environmental conditions

Productivity of arable land Energy is lost from food chains in the following ways: Undigested food and waste Only 10% is incorporated into body tissues Maintaining body temperature Movement

Energy is lost from a food chain through death and decay but not from the food web as the decomposers can still use this as energy

As you move along a food chain, energy is lost between each trophic level and the next. 90% energy lost Cereal plant Farm animal 10% energy passed on 90% energy lost Human 10% energy passed on As a result of this loss of energy, livestock production generates far less food per area of land than plant production.

Shorter food chains have much less loss of energy: 90% energy lost Cereal plant 10, 000 k. J 10% energy passed on Farm animal 1, 000 k. J 90% energy lost Cereal plant 10, 000 k. J Human 10% energy passed on 90% energy lost 1, 000 k. J 10% energy passed on Human 100 k. J

Productivity of arable land Arable land planted with crops produces far more food than the same land planted with grass to feed livestock. However, not all land can be planted with crops.

Use of Land Not all land is suitable for the growth of crops. Rocky hillsides, mountainous areas, tundra…are all areas where crop growth is not successful. In these conditions it is more productive to grow livestock than crops