D. Population Density, Acres of Crop Land, and Food Availability
1. The number of people per cultivated acres is not related to food availability.
2. Cash is necessary if you don't grow your own food. As long as food is bought and
sold in a society with great income differences, hunger is not related to the number of
people per cultivated acre, who grows the food, or who works the fields but how much
money a person has to purchase food.
Fig. 10.3 This graph demonstrates two phenomena: the long-term rise in yields and the effects of droughts in 1970, 1973, 1980, 1983, and 1988. (8000 kg/hectare=3.5 tons/acre).
Fig. 10.7 (a) Changes in per capita food production by region (1961 = 100). (b) World per capita grain production, 1950-1998
THE PRODUCTION AND DISTRIBUTION OF FOOD
I. The Production and Distribution of Food
A. Subsistence Agriculture
1. Slash and Burn
B. The Transformation of Traditional Agriculture to Modern Agriculture
1. Shift From Animals to Machines
2. Increase in Acreage Cultivated (can do more with fewer people)
3. Use of Chemical Fertilizers and Pesticides
4. Use of Irrigation
5. Refrigerated Transport (can sell what you could grow)
6. High Yield Crop Varieties
C. Green Revolution
1. Two Choices - only one possible
a. Increase production of glucose by altering process of photosynthesis.
b. Decrease calories plants put into nonfood portion of plant.
2. Decreased Calories Plants Put into Nonfood Portion of Plant
a. Decreased root mass
·Plants dependent upon irrigation and fertilizers
b. Decreased plant height
·Plants dependent upon herbicides
3. Decreased Genetic Diversity
a. Few varieties of crops species grown
b. Increased susceptibility to insects and disease
1. Allows Crossbreeding of Genetically Different Plants
2. Can Select Desired Characteristics
E. Prospects for Increasing Food Production Using Existing Practices
II. Food Distribution and Trade
A. Patterns in Food Trade
Fig. 10.10 The Food Guide Pyramid indicates what foods will provide adequate nutrition and keep weight under control. Suggested numbers of servings are given as a range, because energy requirements vary for people depending on their size, age and level of activity.
Fig. 10.12 The Sahel is a band of dry grasslands that stretches across the continent. The map shows the countries where civil wars and droughts have recently brought on serious famines.
IV. Building Sustainability Into Agriculture - Developed versus Developing Countries
A. For sustainability, ecosystems dispose of wastes and replenish nutrients by recycling all
B. For sustainability, ecosystems use sunlight as their source of energy.
C. For sustainability, the sizes of consumer populations are maintained so that overgrazing
or other overuse does not occur.
D. For sustainability, biodiversity is maintained.