Food and Agriculture

Chapter 15

Feeding the World

Objectives• Identify the major causes of malnutrition• Compare the environmental costs of

producing different types of food• Explain how food distribution problems

and drought can lead to famine• Explain the importance of the green

revolution

15-1Feeding the World• More food needed because

of population growth

• Some agricultural practices have led to environmental damage

Humans and Nutrition

• We eat food to get the energy to run our body processes

• Malnutrition results when the body does not get enough of these nutrients (calories)

Sources of Nutrition

–A healthy diet is one that has a balance of all nutrients

–People in developed countries tend to eat diets high in proteins and fats

The Ecology of Food

–As populations grow we need more land to grow crops

•Forests cut down

–Different types of agriculture have different impacts of the environment and levels of efficiency

•The efficiency of the amount of food produced per given area–Ideally you want practices the produce the most crop but least impact

–Scientists research and produce plants with higher yield

–More energy, water, and land are used to produce a Calorie of food from animals than from plants

• World Food Problems

–Most people are malnourished because they don’t get enough food

•Food is distributed unevenly

•Droughts and famine

Malnurished citizens of Bangladesh

The Green Revolution

–World wide crop yield have increased because of the use of new varieties and the application of modern agricultural techniques

Green Revolution

•Negative impacts

–Crops often need a lot of water, fertilizer, and pesticides

–Hurts subsistence farmers

Subsistence Farming vs. the Green Revolution

Crops and SoilObjectives• Distinguish between traditional and modern

agricultural techniques• Describe fertile soil• Describe the need for soil conservation• Explain the benefits and impacts of pesticide

use• Describe what is involved in integrated pest

management• Explain how genetic engineering is involved in

agriculture

• The Earth has a limited area of arable land–Can this land support the

billions of people on our planet??

• Agriculture: Tradition and Modern–The basic process of farming

includes plowing, fertilization, irrigation, and pest control

–Most of this work is done by machines in industrialized countries

• Fertile Soil: The living Earth–Soil that can support the growth of healthy plants is fertile•Plant roots grow in topsoil (surface layer of soil)

Soil

•Composed of living organisms, rock particles, water, air and organic matter

•Most soil is formed due to weathering

Soil porfile

Erosion is a global problem–Plants need topsoil to grow

• Erosion is the weathering of rock or soil

– River erosion

– Dust Bowl

Land degradation

–caused by humans and natural processes change land so it can no longer support the local ecosystem

Desertification – land becomes more desert-like

Soil conservation

• helps reduce erosion and protects soil

–Terracing

–Contour plowing

–No-till farming

Enriching the Soil

• Traditionally soil was enriched using mostly inorganic material

• Now inorganics are used

–Can hurt waterways

–Composing helps return nutrients to the soil

Salinization

• Accumulation of salt (salinization) can also damage soil and prevent crops from growing

–Happens naturally and unnaturally (irrigation)

Pest Control

• 13% of all crops grown in N. America are eaten by insects–33% worldwide

Pesticides–Farmers use pesticides to protect crops but problems can develop•Harms beneficial plants, insects, wildlife, and people

•Pesticide resistance•Lingers in the environment

–Biological Pest control

•Use of other organisms to control pests

•Breed plants to be more resistant

•Disrupting insect breeding

–Integrated Pest Management

•Reduce pest damage to a level that causes minimal economic damage

• Engineering a Better Crop

–Use of genetic engineering to produce more desirable traits

•Takes genes from one organism and puts in another

•Genetically modified plants are a result–May have an environmental impact

• Sustainable Agriculture

–Farming that conserves natural resources and helps keep the land productive indefinitely

Animals and Agriculture

• Explain how overharvesting affects the supply of aquatic organisms for food

• Describe the current role of aquiculture in providing seafood

• Describe the importance of livestock in provide food and other products

• We need animal products in our diet

• We have domesticated over 50 animals species

–Chickens, sheep, cattle, bees, fish, goats, pigs, etc.

• Food from Water–Fish is an important industry world wide•20% of animal protein

–We have over harvested some fishing areas•Led do complete depletion of some species

aquiculture

•Governments began setting limits

•Aquaculture helps increase number of fish harvested

–Can cause environmental problems

• Livestock

–Chicken, cattle, sheep, pigs, goats, etc.

–Large farms produce most of the food we produce

–Use in farming in developing nations

–Manure is used for fertilizer–Are we treating these animals humanely

–World wide our meat consumption has increased