Food and AgricultureFeeding a hungry planet

Test Your Knowledge: T or F? Agriculture is a declining industry and its importance is decreasing

because of its lower contribution to GNP and employment.

FALSE: In fact, Agriculture is important because everybody eats food and lower income groups spend a large portion of their income on food. Nutritious food benefits everyone.

Food production problems have been solved. Food prices are lower and there are surpluses.

FALSE: Although new production technologies have increased harvest yield, they create new ecological and economic concerns. World food demand will increase with urbanization, increasing population, and rising income levels.

Agriculture can only be destructive/harmful to ecosystems and natural resources.

FALSE: New approaches to agriculture, including integrated pest management and more sophisticated understanding of production techniques, can have positive impacts on natural systems.

Test Your Knowledge: T or F? Insects are harmful and eliminating them will benefit

humans. FALSE: It’s true that many insects eat plants and can

affect plant production. However, the elimination of some insect pests has disrupted natural predator-prey systems and resulted in decreased food production.

The addition of more nutrients automatically results in increased food production.

FALSE: More isn’t always better. More nutrients can lead to eutrophication. Instead, careful and systematic use of fertilizers can result in increased production without increasing fertilizer application.

KEY TERMS AND CONCEPTS

Photosynthesis IrrigationPesticides PhytoplanktonIPM Integrated Pest Management Transpiration Eutrophication Green RevolutionSustainable Agriculture Fertilizers Livestock BiotechnologyCertified Organic

Reading Objectives Understand the physical constraints on food production Explain the key inputs required for sustained crop yield Discuss the challenges and advances in increasing yields Describe the challenges encountered in controlling pest

since the early 20th century Describe the challenges in growing animals for food Discuss the benefits and challenges of Genetic

modification of agricultural products Discuss energy issues in agriculture Discuss advances in sustainable agriculture Discuss the challenges in feeding a growing population

Food, Nutrition, Hunger 800 million people are undernourished,

95% of them live in developing countries, mostly Africa and Asia

Agricultural production is impacted by weather, agricultural mismanagment, and sociopolitical crises Famine: large scale food shortages

triggered by hurricanes, tsunamis, insects Lead to starvation, disruption, migration

Food insecurity, malnutrition

Case Studies Wangari Maathai – Green Belt

Movement World Hunger: Past, Present, Future

summarize

Human Nutritional RequirementsTo thrive and survive, people need: Dietary Energy Proteins Carbohydrates Dietary Fats Vitamins MineralsMalnutrition or malnourishment is a lack of specific nutrients in the diet, although there may be enough calories

http://www.fao.org/docrep/007/y5686e/y5686e00.htm

DiseasesHalf the world’s population suffers from some vitamin, mineral or protein deficiency Kwakshiorkor – lack of protein, enough carbs Marasmus – low in protein and calories Goiter - iodine Rickets – Calcium, Vitamin D Beriberi – Vitamin B1 Pellagra – Vitamin B3 Scurvy – Vitamin C Anemia - Iron Obesity – low nutrient content with overabundance of

calories

Food sources Legumes, cereals, grains, nuts and seeds,

fruits make up plant proteins Wheat, rice, corn are primary grains Eight animals make up people’s protein

supply Large scale livestock farming consists of

penning animals in high concentration – leads to waste production and disease

Antibiotics are overused leading to antibiotic resistance

Farm Policy Farmers are paid subsidies by the

government, which can create imbalance in commodity value and affordability

Soil Review

O – organic, leaf litter, etcA – Topsoil is where insects and organic matter are concentrated. If topsoil erodes away, plants cannot grow.E – zone of leachingB – can support roots but does not have organic matterC – parent material from weathered bedrock

Soil types

A mixture of clay, silt and sand provides proper aeration (space for seeds to sprout and roots to grow), infiltration (movement of water so nutrients can dissolve), and support.

Soil degredation Erosion caused by wind, weather Human activity –

Removing crops from soil (extracts nutrients)

Excessive use of irrigation salinization Excessive use of pesticides, herbicides Monoculture lack of biodiversity overgrazing

Reading and Video http://www.learner.org/courses/envsci/un

it/text.php?unit=7&secNum=1

Go to your assigned section; take notes and prepare to communicate what you learned.

Biomagnification Objectives Participants will develop an

understanding of why some toxicants (such as pesticides) bioaccumulate.

Most chemicals that bioaccumulate dissolve in lipids and therefore are not excreted but stay in body tissue

Biomagnification MaterialsOil Fishing pole 16 test tubes Red dyeRed marker 1- liter beaker5 - 100 ml beakers Pipettes 2 - 400 ml beakers Stirring rods (one per participant)Fish consumption advisories

Bioaccumulation Procedure Some chemicals accumulate in the fat of animals, like the pesticide DDT

that was used to kill Insects in order to protect crops. ZOOPLANKTON: 16 participants will represent zooplankton. Each will get

a test tube that contains 3 parts water and 1 part oil. These layers represent the fat and water in the organism.

LITTLE FISH: 4 participants will be little fish. Each will get one 100 ml beaker.

BIG FISH: 2 participants will be big fish. Each will get one 400 ml beaker. FISHERPERSON: 1participant will be a fisherman/woman. This person

gets the fishing pole and a 1 liter beaker.

The solution you see is made of red dye and oil and it represents a fat soluble pesticide chemical like DDT

Biomagnification Activity “While the zooplankton were feeding on algae, they

digested 4 drops of pesticide. These 4 drops did not kill them or make them sick. However, more then 7 drops would have.”

Zooplanktons: Put 4 drops of the “pesticide” in your test tube and stir. Notice the “pesticide” stays in the oil. “Each little fish will eat 4 zooplankton.”Little fish: Pour the contents of 4 zooplankton into your beaker. Keep track of the amount of “pesticide” in each little fish. “Each big fish will eat 2 little fish.”Big fish: Pour the contents of 2 little fish into your beaker. Keep track of the amount of “pesticide” in the fish.

Discussion The angler catches and eats two big fish.

How many drops of “pesticide” are in the human?

It takes 80 drops to kill or make the human sick. How many more infected fish could this human safely eat?

Why are pesticides are used in agriculture? Are there other ways to grow crops without using pesticides?