Food and Agriculture

1. Food and Agriculture Chapter 15

2. Bellringer

3. 15.1 Feeding the World

4. Section 1: Feeding the World Preview • Feeding the World • Humans and Nutrition • Sources of Nutrition • Diets Around the World • The Ecology of Food • Food Efficiency • Old and New Foods • World Food Problems • Unequal Distribution • Droughts and Famines • The Green Revolution

5. Objectives • Identifythe major causes of malnutrition. • Comparethe environmental costs of producing different types of food. • Explainhow food distribution problems and drought can lead to famine. • Explainthe importance of the green revolution

6. Famine • the widespread malnutrition and starvation in an area • due to a shortage of food, usually caused by a catastrophic event.

7. Modern agriculture practices • provide most of the world’s population with enough food to survive. • However, some of these practices can cause environmental damage that eventually makes growing food crops more difficult.

8. Humans and Nutrition • The human body uses food • as a source of energy and • as a source of materials for • building and • maintaining body tissues.

9. Calories • The amount of energy that is available in food is • One Calorie is equal to • 1,000 calories or • one kilocalorie.

10. The three major nutrients needed • carbohydrates, • proteins, and • Lipids (fats , steroids) • In addition • smaller amounts of vitamins and minerals to remain healthy.

11. Humans and Nutrition (copy to notes)

12. A disorder of nutrition results when a person does not consume enough of each of the nutrients that are needed by the human body. Many forms of malnutrition depending on the diet Example: Need 8 essential amino acids from proteins. This is easily done if a variety of foods is eaten. However, if the only sources of food is corn and rice, which contain protein, but lacks one of the essential amino acids. Amino acid deficiency can result Malnutrition

13. Sources of Nutrition • Diet • the type and amount of food that a person eats. • A healthy diet • maintains a balance of the right amounts of nutrients, minerals, and vitamins.

14. Food • Grains • produced in the greatest amounts worldwide, • plants of the grass family whose seeds are rich in carbohydrates. • Besides eating grains, most people eat • fruits, vegetables, and smaller amounts of meats, nuts, and other foods that are rich in fats and proteins.

15. Sources of Nutrition

16. Diets Around the World • People worldwide generally • consume the same major nutrients and • eat the same basic kinds of food. • But, diets vary by region. • People in more developed countries • tend to eat more food and • a larger proportion of proteins and fats than people in less developed countries.

17. Diets Around the World

18. The Ecology of Food • As the human population grows, • farmland replaces forests and grasslands. • Feeding everyone while maintaining natural ecosystems becomes increasingly difficult. • Different kinds of agriculture have • different environmental impacts and • different levels of efficiency.

19. Food Efficiency • The efficiency of a given type of agriculture • a measure of the quantity of food produced on a given area of land with limited inputs of energy and resources. • An ideal food crop is • one that efficiently produces a large amount of food • with little negative impact on the environment.

20. Food Efficiency • On average, • more energy, water, and land are used to produced a Calorie of food from animals than to produce a Calorie of food from plants. • Animals that are raised for human use • are usually fed plant matter, • but because less energy is available at each level on a food chain, • only about 10 percent of the energy from the plants gets stored in the animals.

21. Food Efficiency Thus, a given area of land can usually produce more food for humans when it is used to grow plants than when it is used to raise animals.

22. The efficiency of raising plants for food is one reason why diets around the world are largely based on plants. • However, meat from animals generally provides more nutrients per gram than most food from plants.

23. Old and New Foods • Researchers hope to improve the efficiency of food production by studying plants and other organisms that have high yield.

24. Yield • is the amount of crops produced per unit area. • Researchers are interested in • organisms that • can thrive in various climates and • do not require large amounts of fertilizer, pesticides, or fresh water. • Some organisms have been a source of food for centuries, while other sources are just being discovered.

25. World Food Problems • Malnourishment occurs because • people simply do not get enough food. • More food is needed each year to feed the world’s growing population. • World food production • has been increasing for decades, • but now food production is not increasing as fast as the human population is increasing.

26. World Food Problems

27. Unequal Distribution • If all the food in the world today were divided equally among the human population, • no one would have quite enough food for good health. • But food is not divided equally, • malnutrition is largely the result of poverty. • Even in the US, many of the poor suffer • Wars and political strife • can also lead to malnutrition because they interrupt transportation systems.

28. Droughts and Famines • A drought • is a prolonged period during which rainfall is below average, and • crops grown without irrigation may produce low yields or fail entirely. • Is more likely to cause famine in places where most food is grown locally.

29. Droughts and Famines • If a drought occurs, • there may be no seed to plant crops the following year. • The effects of a drought can continue for years.

30. People in a given area • can usually survive one crop failure. • They may have saved enough food from previous seasons, or they may have systems for importing food from elsewhere.

31. But several years of drought • cause severe problems for any area of the world. • For example, • after a long drought, • the soil may be less able to support the production of food crops.

32. The Green Revolution • Worldwide, between 1950 and 1970, • increases in crop yields resulted from • the use of new crop varieties and • the application of modern agriculture techniques. • Since the 1950s, the green revolution • has changed the lives of millions of people. • However, also had some negative effects.

33. For example, • Most new varieties of grain • produce large yields only if they receive large amounts of water, fertilizer, and pesticides. • In addition, the machinery, irrigation, and chemicals required by new crop varieties can degrade the soil if they are not used properly.

34. As a result of the overuse of fertilizers & pesticides, • yields from green revolution crops are falling. • The grain production in the U.S. has decreased since 1990, • partly because the amount of water used for irrigation has decreased.

35. In addition, The Green Revolution • a negative impact on subsistence farmers, or farmers who grow only enough food for local use. • Before the green revolution, • subsistence farmers worked most of the world’s farms. • But they could not afford the equipment, water, and chemicals needed to grow new crop varieties.

36. Known Unknown Solution Math Practice

37. Quick Check 15.1

38. Bellringer

39. Section 2: Crops and Soil Preview • Agriculture: Traditional/Modern • Fertile Soil: The Living Earth • Soil Erosion: A Global Problem • Land Degradation • Soil Conservation • Enriching the Soil • Salinization

40. Objectives • Distinguishbetween traditional and modern agricultural techniques. • Describefertile soil. • Describethe need for soil conservation.

41. Crops and Soil

42. Arable land • is farmland • limited area of arable land. • Dilemma • As the human population increases, • the amount of arable land per person decreases.

43. Agriculture: Traditional • The basic processes of farming include plowing, fertilization, irrigation, and pest control. • Plows helps • mixing soil nutrients, • loosening soil particles, and • uprooting weeds. • Organic fertilizers, such as manure, • Fields are irrigated by ditches.

44. Agriculture: Modern • The basic processes of farming are now carried out using modern agricultural methods. • powered by fossil fuels • Synthetic chemical fertilizers have replaced manure and plant wastes • A variety of overhead sprinklers and drip systems may be used for irrigation. • Synthetic chemicals are used to kill pests.

45. Fertile Soil: • Supports the growth of healthy plants

46. 6 Basic Layers • Surface liter • Topsoil • Zone of leaching • Subsoil • Rock particles • Bedrock, which is the solid rock from which most soil originally forms.

47. Fertile Soil: The Living Earth

48. Topsoil • surface layer of the soil, • usually richer in organic matter • composedof • living organisms, • rock particles, • water, • air, and • organic matter, such as dead or decomposing organisms.

49. Soil • forms when rock is broken down into smaller and smaller fragments by • wind, • water, and • chemical weathering. • happens when the minerals in rock react chemically with substances to form new materials. • Temperature changes & moisture can cause rock to crack and break apart. • a few centimeters of soil can take hundreds or even thousands of years to form

50. Other processes affected topsoil • the rock particles supply mineral nutrients • Fungi and bacteria decompose dead plants as well as organic debris  nutrients • Earthworms, insects, and other small animals help by • breaking up the soil and • allowing air and water into it.