Chapter 7: Sustaining Terrestrial Resources

Chapter 7: Sustaining Terrestrial Resources

Terrestrial Resources Depend on Fertile Soils

Central Question

7.1-7.3 Science

7.1 Climate, biodiversity, and nutrients influence terrestrial primary production

Species-Richness Effects

Soil Nutrients

The Nitrogen Cycle

nitrogen fixation

THE NITROGEN CYCLE

KEY PROCESSES

1 NITROGEN FIXATION

2 DECOMPOSITION and AMMONIFICATION

3 NITRIFICATION

4 NITROGEN ASSIMILATION

5 DENITRIFICATION

6 WEATHERING

Think About It

7.2 Agriculture, forestry, and grazing systems are built on the natural biomes

Farming

terrestrial harvest systems

Ranching

Forestry

Think About It

7.3 Soil structure and fertility result from dynamic processes

TEEMING WITH LIFE, SOILS ARE HOME TO A VAST ARRAY OF BIODIVERSITY

COMBINED EFFECTS OF CLIMATE AND ORGANISMS PRODUCE MAJOR DIFFERENCES AMONG THE TYPICAL SOILS OF EARTH’S BIOMES

Soil Structure

BASIC SOIL STRUCTURE CONSISTS OF A VERTICAL SEQUENCE OF SOIL HORIZONS

SOIL HORIZONS

O HORIZON

A HORIZON

E HORIZON

B HORIZON

CHORIZON

R HORIZON

Soil Development

Think About It

7.1-7.3 Science: Summary

7.4–7.9 Issues

7.4 Industrial agriculture, which increases production, comes with environmental impacts

NORMAN BORLAUG SHOWING THE RESULTS OF WHEAT BREEDING EXPERIMENTS, WHICH WERE KEY TO THE GREEN REVOLUTION

⚠ Think About It

7.5 Common farming, grazing, and forestry practices deplete soils

Soil Loss by Erosion

Conventional-Tillage Agriculture

Overgrazing of Rangelands and Desertification

conventional-tillage

CONVENTIONAL-TILLAGE AGRICULTURE EXPOSES BARE SOIL TO EROSIVE FORCES

Think About It

OVERGRAZING HAS RESULTED IN HIGH RATES OF EROSION ON MANY RANGELANDS

OVERGRAZING HAS CONTRIBUTED TO DESERTIFICATION

7.6 Deforestation and some forestry management practices deplete soils and increase flooding danger

Forest Harvest and Clearing

LOGGING ACTIVITIES COMMONLY PRODUCE SIGNIFICANT SOIL DISTURBANCE

Fire Suppression

FIRE PROTECTION IN FORESTS OF THE WESTERN UNITED STATES HAS INCREASED THE DENSITY OF TREE POPULATIONS

Think About It

OFTEN THE LONG-TERM CONSEQUENCE OF FIRE PROTECTION HAS BEEN, IRONICALLY, CATASTROPHIC FIRE

THREE MAIN FORMS OF CROP IRRIGATION IN USE TODAY

7.7 Irrigation can damage soils

Irrigation Systems

Irrigation and Waterlogged and Saline Soils

IRRIGATION CAN RESULT IN WATERLOGGED SOILS AND SOIL SALINIZATION

Think About It

7.8 Intensive agriculture can cause pollution and promote pesticide resistance

Pest Control and Pollution

MANY ORGANISMS REDUCE HUMAN FOOD SUPPLIES

PESTICIDE COSTS TAKE A BITE OUT OF PROFITS

pesticide resistance

Pesticide Resistance and Loss of Insect Predators

Think About It

7.9 Genetically modified crops are sources of controversy and agricultural potential

Status of GM Crops

BACTERIAL GENES HAVE BEEN IMPLANTED IN SEVERAL CROP PLANTS TO MAKE THEM MORE RESISTANT TO INSECT ATTACKS

GM Crops: The Potential and the Controversy

GOLDEN RICE: BIOTECHNOLOGY THAT TARGETS A GLOBAL SOURCE OF MALNUTRITION

DEVELOPMENT OF GENETICALLY MODIFIED CROPS RAISES CONTROVERSY

GENETICALLY MODIFIED CROPS: POTENTIAL BENEFITS AND CONCERNS

BENEFITS

CONCERNS

Think About It

7.5–7.9 Issues: Summary

7.10-7.13 Solutions

7.10 Investing in local farmers, while increasing genetic and crop diversity, may be a sustainable approach to feeding our growing population

Supporting Local Farmers

Crop Diversity for Productivity and Sustainability

INCREASING CROP DIVERSITY THROUGH INTERCROPPING: AN ANCIENT PRACTICE

Think About It

7.11 Sustainable farming, forestry, and ranching practices can reduce soil losses and improve soil fertility

Managing Tillage in Agriculture

SEVERAL FARMING PRACTICES CAN REDUCE SOIL EROSION ON AGRICULTURAL LANDS

NO-TILL AGRICULTURE REQUIRES SOME SPECIALIZED EQUIPMENT

no-till (low-till) agriculture

NO-TILL AGRICULTURE CAN REDUCE EROSION RATES SUBSTANTIALLY

Organic Farming

Livestock Stocking Rates and Resting the Land

INTENSITY AND TIMING OF GRAZING ARE KEY TO SUSTAINING RANGELAND PRODUCTIVITY

shelterwood harvesting

selective logging The

Forest Harvest, Landscape Restoration, and Fire Management

AN ANCIENT PRACTICE SUSTAINED FERTILITY OF RAIN FOREST SOILS

An Ancient Practice That Sustains Soil Fertility

AN OLD TECHNIQUE IS BEING USED TO SUSTAIN SOIL FERTILITY

Think About It

7.12 Sustainable irrigation requires careful management of water and salts

Water Management

Salt Management

Think About It

7.13 Integrated approaches to pest control can reduce pesticide pollution and evolution of pesticide resistance

Integrated Pest Management

Integrated Pest Management (IPM)

FARMERS USE “THE REFUGE TECHNIQUE” TO COMBAT Bt RESISTANCE IN CROP PESTS

THE REFUGE TECHNIQUE

Think About It

7.10-7.13 Solutions: Summary

Central Question: How can we produce food and forest products while minimizing environmental impact?

7.1–7.4 Science

7.5–7.9 Issues

Terrestrial Resources and You

Keep informed.

Eat lower on the food chain.

Grow some of your own food.

Buy and consume sustainably produced terrestrial resources.

7.10–7.13 Solutions

Answer the Central Question:

Chapter 7

Review Questions

1. Which of the following ecosystems is most likely to support the highest level of primary production?

2. Which of the following soil horizons generally contains the lowest amount of organic matter?

3. Why do tropical forest soils generally contain low amounts of organic matter?

4. Which of the following is a major source of erosion in forests?

5. In which of the following situations would irrigation most likely produce soil salinization?

6. The individuals carrying genes for pesticide resistance are generally rare in a pest population prior to exposure to a pesticide. What does this suggest about the pesticide-resistant individuals in the population?

7. What determines whether a genetically modified organism (GMO) is transgenic?

8. Which of the following was not part of the Green Revolution?

9. Which of the following approaches to farming will generally have the lowest fuel costs?

10. Which of the following is not part of IPM?

Critical Analysis

Central Question: Can we sustainably manage fisheries and aquaculture?

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