12Cha

pter

386 Chapter 12 • Study Guide

traditional agriculture (366) yield (367) industrial agriculture (367) green revolution (368) biological pest control (369) integrated pest management (IPM) (371) pollinator (371)

Lesson 4 Food production• We need to find a way to increase food production

sustainably.• GM food could be promising, but there are risks.• Industrial food production is efficient, but it has

disadvantages.• There are sustainable alternatives to industrial agriculture.

arable land (373) seed bank (380) food security (374) sustainable agriculture (381) malnutrition (374) organic agriculture (382) genetic engineering (375) genetically modified (GM) organism (375) biotechnology (375) feedlot (378) aquaculture (379)

InquIry LABs And ActIvItIes• Testing Soil Properties Observe the textures of different types of soil and make

a prediction about their permeability. Then test your prediction.

• Combating Erosion See if you can control soil runoff and erosion with an

erosion barrier or with plowing methods.• Local Planting Conditions Use hardiness information and growing seasons to

design a vegetable garden.

Lesson 1 Soil• Soil is a complex substance that forms through weather-

ing, deposition, and decomposition.• A soil profile consists of layers known as horizons.• Soils can be classified by color, texture, structure, and pH.

soil (352) soil profile (355) parent material (353) clay (356) bedrock (353) silt (356) weathering (354) sand (356) soil horizon (355) loam (356)

Lesson 2 Soil Degradation and Conservation• Certain farming, ranching, and forestry practices can

erode soil, but other practices can protect it.• Desertification reduces productivity of arid lands.• U.S. and international agricultural organizations promote

soil conservation.• Irrigation and pesticides can improve soil productivity in

the short term but can pollute soil in the long term.

soil degradation (358) contour farming (359) intercropping (359) overgrazing (360) crop rotation (359) desertification (361) cover crop (359) irrigation (363) shelterbelt (359) salinization (363) tilling (359) pesticide (364) terracing (359)

Lesson 3 agriculture• Agriculture began about 10,000 years ago, when humans

began to plant seeds and raise livestock.• Industrial agriculture and the green revolution have saved

millions of people from starvation.• Chemical pesticides, biological pest control, and integrated

pest management can all effectively protect crops from pests.

• Many insects and other animals are essential to the repro-duction of crop plants.

How can we balance our growing demand for food with our need to protect

the environment?

Lesson 2 How do erosion, desertification,

and soil pollution affect the productivity of soil?

Lesson 1 What is soil?

Lesson 4 How can we produce enough food for

a rapidly growing population while sustaining our ability to produce it?

Lesson 3 How has agriculture evolved?

Study ReSouRceS

Chapter 12 Self Test • Chapter 12 Worksheets • Chapter 12 Overview Presentation (for PowerPoint)

Soil and Agriculture 387

The Central Case in this chapter explored issues surrounding the appearance of corn transgenes in Mexico. People are concerned that crops with transgenes could crossbreed with native varieties and contaminate their genetic material. Based on what you have learned, are such concerns valid? Use examples from the Central Case and the lessons to support your opinion.

5. Arid and semiarid lands are prone to desertifica-tion because

a. the Sahara is expanding. b. gigantic dust storms blow sand from China

into North America. c. the precipitation cannot meet the growing

human demand for water. d. 10 percent of productivity is lost to erosion.

6. Traditional agriculture may use all of the follow-ing EXCEPT

a. teams of work animals. b. irrigation. c. fossil fuels. d. organic fertilizer.

7. Efficient industrial agriculture requires that large areas be planted with

a. contoured and well-plowed fields. b. a single crop. c. native organisms. d. cover crops.

8. Because of the green revolution, between 1961 and 2008, food production

a. increased 150 percent while the population doubled.

b. kept pace with population growth. c. did not increase. d. was mostly organic.

9. A secure food supply depends on all of the follow-ing EXCEPT

a. maintaining healthy soil and water. b. increased use of fertilizer. c. safe distribution of the food. d. biodiversity.

10. Industrial food production includes a. aquaculture. b. monocultures. c. feedlots. d. all of the above.

Review Concepts and Terms 1. About how much of Earth’s land surface is used

for agriculture? a. 8 percent c. 28 percent b. 18 percent d. 38 percent

2. The organic matter in soil includes a. minerals. b. living and decomposing organisms. c. living organisms only. d. bedrock.

3. Crop rotation does all of the following EXCEPT a. minimize erosion. b. let fields lie fallow. c. return nutrients to the soil. d. break cycles of disease.

4. Which soil conservation technique is shown in the photo below?

a. reduced tillage b. shelterbelts c. contour farming d. terracing

ANSWERS

Chapter Assessment For answers to the Chapter Assessment, see page A–19 at the back of the book.

12Cha

pter

388 Chapter 12 • Assessment

Modified True/False Write true if the statement is true. If it is false, change the underlined word or words to make the statement true.

11. It takes one year to produce one inch of topsoil. 12. Acid precipitation and the leaching of minerals

and metals affect the pH of soil and the types of plants that can grow in it.

13. Today, human activities cause less erosion than natural events.

14. Although labor-intensive, intercropping is prob-ably the only sustainable way to farm mountains.

15. Desertification is the loss of more than 50 percent of soil productivity.

Reading Comprehension Read the following selection, and answer the questions that follow.Most GM crops are insect- and/or herbicide- resistant. Farmers are willing to pay higher prices for such GM seeds because they expect to spend less money on pesticides and herbicides. Corn, soy-beans, cotton, and canola dominate the GM market. These GM crops are used mostly in animal feed, fab-ric or yarn, or processed food. For these uses, most people are willing to accept GM crops.

Although GM produce such as strawberries and potatoes has been marketed in the U.S., GM research involving fruits and vegetables has dropped signifi-cantly over the past several years. Companies are introducing fewer new GM products. Lack of con-sumer support means that only a narrow range of GM crops will be produced. If the trend continues, biotechnology may not realize its full potential.

16. Why do soybeans, corn, cotton, and canola domi-nate the GM crop market?

a. They are mostly inexpensive to produce. b. Such crops prevent malnutrition and clothe the

poor. c. They are mostly used for animal feed, fabric

or yarn, and processed food, so most people accept them.

d. They are the only GM crops exempt from U.S. regulations.

17. Why have most GM crops been modified for resistance to herbicides and insects?

a. Such crops are safer for the environment. b. Such crops are safer for human health. c. Farmers expect to save money by planting

them. d. The resistance makes fruits and vegetables taste

better.

Short Answer 18. Do you think it is necessary to safeguard native

crop varieties? Explain. 19. When it comes to weathering and decomposition,

how do the activities of organisms help form soil? Give two examples of how organisms produce the mineral and organic matter in soil.

20. What is intercropping? List three benefits of intercropping.

21. How did growing wheat and grazing cattle con-tribute to the Dust Bowl?

22. Is it true that monocultures risk catastrophic crop failure? Explain.

23. The green revolution required a large energy investment. In 2008, agriculture used 70 times more energy than it did in 1900. What were two consequences of such an increase in fossil fuel use?

Critical Thinking 24. Infer How did agriculture allow for the develop-

ment of civilization? 25. Form an Opinion Would you support legislation

that banned GM food crops? Explain. 26. Explain How do market forces contribute to the

loss of genetic diversity in our crop plants? 27. Infer Per kilogram of meat produced, would you

expect it to be more expensive to raise pigs for pork or cattle for beef?

28. Apply Concepts How would it increase global food security if more crops were engineered to be drought-resistant?

29. Apply Concepts Why is it important to support small farms and urban community gardens?

Ecological Footprints

Data from U.N. Food and Agriculture Organization.

World Population, Food Production, Fertilizer Use, and Farmland

Food productionNitrogen fertilizer use

World population

Agricultural land

20

0

40

60

80

100

1960 1965 1970 1975 1980 1985 1990 1995 2000

Perc

enta

ge

of Y

ear

2000

Val

ue

Year

You

Your class

Your town

Your state

United States

$547.50$1.501

Annual CostDaily CostPopulation

Pirog, R., and A. Benjamin. 2003. Checking the food odometer: Comparing food miles for local versus conventional produce sales to Iowa institutions. Ames, IA: Leopold Center for Sustainable Agriculture, Iowa State University.

Soil and Agriculture 389

2. Both gasoline and diesel prices can rise suddenly. How might future increases in fuel prices affect food prices in your area?

3. Our current system of food production relies on long-distance transportation. What are some ways that you can support a more sustainable system?

Read the information below. Copy the table into your notebook, and record your calcula-tions. Then, answer the questions that follow.

In the 1900s, humans industrialized food pro-duction. As a result, we increased the amount of energy used to store food and get it to market. In the United States today, food travels an average of 1500 miles from the field to your table. The price you pay for food covers the long-distance haul-ing cost. On average, it costs about one dollar per ton per mile. If the average person eats 2 pounds of food per day, calculate the food transportation costs for each category in the table. 1. One recent study found that locally produced

food traveled about 50 miles to market and cost 96 percent less to transport than indus-trial food. Locally grown food is fresher and has less environmental impact. As a con-sumer, what might be some disadvantages of relying on local food production?

Analyze DataThe graph below shows agricultural land, world popula-tion, global food production, and nitrogen fertilizer use from 1961 to 2003. Values in the graph were calculated using the data from the year 2000 as 100%. Use the data to answer the questions.

30. Interpret Graphs Describe the growth rate in world population from 1961 to 2003.

31. Interpret Graphs From 1961 to 2003, which variable grew the most and which grew the least? How do you know?

32. Analyze Data Write a ratio to compare nitrogen fertilizer use in 1970 and 1990. Write another ratio to compare global food production in 1970 and 1990. How would you compare the trends in these two data sets?

33. Draw Conclusions Does increasing food produc-tion rely on increasing the use of nitrogen fertil-izer? Explain. (Hint: Look at the trends in the data from 1987 to 1994.)

Write About It 34. Persuasion Write a video script that argues for

engineering GM crops with traits that help small-scale farmers in developing nations. Keep your message brief and compelling.

35. Summary In your own words, write a paragraph summarizing the characteristics of livestock raised with organic methods.

36. Apply the BIGQUESTION Do you believe that feedlots are a “necessary evil”? Explain.