Miller Chapter 12A

Vitamin A deficiency in some developing countries leads to Blindness Death

1999: Porrykus and Beyer Genetically engineered rice with beta-

carotene and more iron

Many of the poor suffer health problems from chronic lack of food and poor nutrition, while many people in developed countries have health problems from eating too much food.

The greatest obstacles to providing enough food for everyone are poverty, political upheaval, corruption, war, and the harmful environmental effects of food production.

Food security : daily access to enough nuritious food

Food insecurity : live with chronic hunger snd poor nutrition 1 in 6 in developing countries Root cause: poverty

Macronutrients Carbohydrates Proteins Fats

Micronutrients Vitamins Minerals

Chronic under nutrition, hunger , mental retardation, stunted growth

Chronic malnutrition: low protein, high-carbohydrate weak, more susceptible to disease, hinders

development

Vitamin and mineral deficiencies in people in developing countries : Iron, Vitamin A, Iodine

Goiter in Bangladesh

Famine : severe shortage of food Usually caused by

crop failures from Drought Flooding War Mass migration

of starving people to other areas

War and the Environment: Starving Children in Famine-Stricken Sudan, Africa

Overnutrition : when food energy intake exceeds energy use and causes excess body fat

Similar health problems to those who are underfed Lower life expectancy Greater susceptibility to disease and illness Lower productivity and life quality

Three systems produce most of our food Croplands: grains 77% use 11% of land area Rangelands, pastures, and feedlots:

16% ,using 29% of the world’s land area Aquaculture: 7%

Importance of wheat, rice, and corn: provide about 47% of the calories , 42% of

the protein Tremendous increase in global food

production technological advancement , machinery

Industrialized agriculture, high-input agriculture uses heavy equipment and large amounts of

financial capital, fossil fuels, water,fertilizer Goal is to steadily increase crop yield Plantation agriculture: developing countries cash crops – bananas, soybeans,

sugarcane,coffee, vegetables on monocultures

Increased use of greenhouses to raise crops

Traditional subsistence agriculture : human labor and draft animals, enough food to feed family only

Traditional intensive agriculture : human and draft animals, fertilizer, water, enough to feed family, sell some for income

Polyculture : several crops on the same plot, crop diversity Benefits over monoculture Slash-and-burn agriculture- clearing in tropical

forests growing a variety of cash crops – 20 types

mature at different times ,keeps soil covered

Soil composition: complex mixture of eroded rock, mineral nutrients, decaying organic matter, water, air and billions of living organisms

Soil formation :bedrock subject to mechanical and chemical weathering and biological processes to form soil

Layers (horizons) of mature soils O horizon: leaf litter A horizon: topsoil , humus B horizon: subsoil, inorganic matter,

(sand,silt,clay,gravel) C horizon: parent material, often bedrock

Soil erosion : water and wind

Green Revolution: increase crop yields(since 1988) Monocultures of high-yield key crops

E.g., rice, wheat, and corn Use large amounts of fertilizers, pesticides, and water Multiple cropping

Second Green Revolution -1967. FAst growing dwarf varieties of rice and wheat . India , China, Central and South America

World grain has tripled in production

Agribusiness : giant multinational increasingly control the growing

Annual sales : more than automative , steel, housing combined .1/5 of the country’s GDP

Food production: very efficient

Percent of income spent on food : 2% of income

Gene Revolution Cross-breeding

through artificial selection

Slow process – 15 years or more to produce a crop

Resulting varieties remain useful for only 5-10 years.

Genetic engineering Genetic modified

organisms (GMOs): transgenic organisms

Age of Genetic Engineering: developing crops that are resistant to Heat and cold Herbicides Insect pests Parasites Viral diseases Drought Salty or acidic soil

Advanced tissue culture techniques

Animals for meat raised in Pastures Densely Packed Feedlots Confined animal feeding

operations

Meat production increased fourfold between 1961 and 2007

Demand is expected to go higher as countries become more industrialized and incomes increase

Aquaculture, blue revolution World’s fastest-

growing type of food production

Raising marine and freshwater species in ponds and underwater cages

Dominated by operations that raise herbivorous species –carp,catfish,tilapia

Integrate crop growing and aquaculture by using rice straw, pig and duck manure to fertilize farm ponds and rice paddies in order to produce phytoplankton eaten by various species of carp

Food production in the future may be limited by its serious environmental impacts, including soil erosion and degradation, desertification, water and air pollution, greenhouse gas emissions, and degradation and destruction of biodiversity.

Fig. 12-9, p. 286

Food Production

Biodiversity Loss Soil Water Air Pollution Human Health

Loss and degradation of grasslands, forests, and wetlands

Erosion Water waste Greenhouse gas emissions (CO2) from fossil fuel use

Nitrates in drinking water (blue baby)Loss of fertility Aquifer depletion

Pesticide residues in drinking water, food, and air

Fish kills from pesticide runoff

SalinizationIncreased runoff, sediment pollution, and flooding from cleared land

Greenhouse gas emissions (N2O) from use of inorganic fertilizersWaterlogging

Killing wild predators to protect livestock

Contamination of drinking and swimming water from livestock wastes

Desertification Pollution from pesticides and fertilizers

Greenhouse gas emissions of methane (CH4) by cattle (mostly belching)

Loss of genetic diversity of wild crop strains replaced by monoculture strains

Algal blooms and fish kills in lakes and rivers caused by runoff of fertilizers and agricultural wastes

Bacterial contamination of meat

Other air pollutants from fossil fuel use and pesticide sprays

Environmental Impacts of food production

Soil erosion : movement of soil components Natural causes-wind, water Human causes-

Two major harmful effects of soil erosion Loss of soil

fertility:depletion of plant nutrients in topsoil

Water pollution in surface waters, sediment, residues of fertilizers and pesticides

Fig. 12-11, p. 287

Stepped Art

Stable or nonvegetative

Serious concern

Some concern

Global Soil Erosion

Desertification Moderate: 10-25% dropSevere : 25-50% drop

Very severe ; more than 50% - gullies, dunes

Effect of global warming on desertification increase drought in arid areasdrop in food production,

Sahel region in W Africa

Irrigation problems Salinization: accumulation of salts -Asia Waterlogging : water accumulates

underground and raises the water table

Expansion of the green revolution requires huge inputs of fertilizer, pesticide, water,

otherwise yields not much more than traditional crops

costs too much for subsistence farmers Depletion of water, soil salinization, climate

changeSolutions Irrigating more cropland? 80% increase by 2050 Cultivating more land? mostly marginal land. Using GMOs? increase yield /acre Multicropping

Industrialized food production and consumption have a large net energy loss

Industrialized Agriculture uses ~17% of All Commercial Energy Used in the U.S.

Fig. 12-16, p. 291

Projected Advantages

Projected DisadvantagesIrreversible and unpredictable genetic and ecological effects

Need less fertilizer

Need less water

More resistant to insects, disease, frost, and drought

Harmful toxins in food from possible plant cell mutations

Grow faster New allergens in foodCan grow in slightly salty soils

Lower nutrition

Increase in pesticide- resistant insects, herbicide- resistant weeds, and plant diseases

May need less pesticides

Tolerate higher levels of herbicides

Higher yieldsCan harm beneficial insects

Less spoilage Lower genetic diversity

GENETICALLY MODIFIED FOODS

Biodiversity threatened when Forest and grasslands are replaced with

croplands tropical forests and cerrado (savanna) in Brazil

Agrobiodiversity threatened when Human-engineered monocultures are used Replacing nature’s resilient genetic diversity India – 30,000 varieties of rice, now only 10

Importance of seed banks Newest: underground vault in the Norwegian

Arctic

Fig. 12-18, p. 293

Aquaculture

Advantages Disadvantages

Needs large inputs of land, feed, and water

High efficiency

High yield in small volume of water

Large waste output

Can destroy mangrove forests and estuaries

Can reduce overharvesting of fisheries

Uses grain to feed some speciesLow fuel use

High profitsDense populations vulnerable to disease

Producing Fish through Aquaculture Can Harm Aquatic Ecosystems

We can sharply cut pesticide use without decreasing crop yields by using a mix of cultivation techniques, biological pest controls, and small amounts of selected chemical pesticides as a last resort (integrated pest management).

What is a pest – interferes with human welfare

Natural enemies—predators, parasites, disease organisms—control pests In natural ecosystems In many polyculture agroecosystems

Pesticides Insecticides – insects killers Herbicides – weed killers Fungicides – fungus killers Rodenticides – rat and mouse killers

Herbivores overcome plant defenses through natural selection: coevolution

First-generation pesticides-natural chemicals from plants

Second-generation pesticides Paul Muller: DDT Nobel Prize 1948 Benefits versus harm

Broad-spectrum agents – toxic to many pests and non-pest species. Chlorinated hydrocarbons: DDT, organophosphates : malathion, parathion

Selective or narrow spectrum agents - Persistence – length of time they remain

deadly in the environment for years, biologically magnified in food webs

Biologist : DDT use was increasing to control mosquitoes

Silent Spring - 1962 Potential threats of

uncontrolled use of pesticides

Gave impetus to the US environmental movement

Save human lives prevented deaths from malaria, typhus and bubonic plague : at least 7 million people

Increases food supplies and profits for farmers protect 55% of the world’s food supply. Profit $1:$4

Work quickly, long shelf life, easily shipped and applied

Health risks are very low relative to their benefits

New pest control methods: safer and more effective

Accelerate the development of genetic resistance, 5 to 10 years, sooner in

the tropics

Financial treadmill

Kill natural predators and parasites that help control

Only 0.1-2% of the pesticide applied by aerial or ground spraying reaches

the target pest. Rest pollutes air, water, harm wild life, affect human

health

Expensive for farmers

Some insecticides kill natural predators and parasites that help control the

pest population

Pollution in the environment

Some harm wildlife

Some are human health hazards

David Pimentel: Pesticide use has not reduced U.S. crop loss to pests Loss of crops is about 31%, even with 33-

fold increase in pesticide use High environmental, health, and social

costs with use, $5-10 in damages for every $1 spent

Use alternative pest management practices could halve the use of chemical pesticides on 40 major US crops

Pesticide industry refutes these findings Campbell soup tomatoes in Mexico, Rice in

Indonesia, Sweden

Best-selling herbicide (Roundup), Monsanto

Advantages – does not harm living things, degrades into harmless substances within weeks

Disadvantages - resistant weeds , expensive to develop other pesticides

1955: Dieldrin sprayed to control mosquitoes

Malaria was controlled

Dieldrin didn’t leave the food chain

Domino effect of the spraying

Happy ending

U.S. federal agencies EPA USDA FDA

Effects of active and inactive pesticide ingredients are poorly documented

Circle of poison, boomerang effect – residues of banned chemicals exported to other countries may come back on food, winds carry persistent pesticides such as DDT

1998 – 50 countries developed treaty that requires exporting countries to have consent from importing countries for exports of 22 pesticides , 5 industrial chemicals

2000 – 100 countries signed to phase out 12 of the most hazardous persistent organic pollutants (POP’s), 9 of them hydrocarbons (DDT)

United States has not signed this agreement

Fool the pest : rotate crops, adjust plant times

Provide homes for pest enemies

Implant genetic resistance : GMO’s

Bring in natural enemies : natural predators

Use insect perfumes

Hormones Scald them

Integrated pest management (IPM) Coordinate:

cultivation, biological controls, and chemical tools to reduce crop damage to an economically tolerable level

Disadvantages expert knowledge

Control prices – keep artificially low Provide subsidies – price supports, tax

breaks, subsidies for 31% of global farm income Developed : $280 billion /year Substitute traditional subsidies with ones

that promote sustainable farming practices Subsidies to fishing – promotes destructive

fishing practices Let the marketplace decide

United Nations Children’s Fund (UNICEF) suggests these measures. Can be done at an average annual cost of $5-10 / child Immunizing children against childhood

diseases Encourage breast-feeding Prevent dehydration in infants and children Prevent blindness – Vitamin A capsule

(75c/child) Provide family planning services Increase education for women

Sustainable food production will require reducing topsoil erosion, eliminating overgrazing and overfishing, irrigating more efficiently, using integrated pest management, promoting agrobiodiversity, and providing government subsidies for more sustainable farming, fishing, and aquaculture.

Producing enough food to feed the rapidly growing human population will require growing crops in a mix of monocultures and poly cultures and decreasing the enormous environmental impacts of industrialized food production.

Soil conservation, some methods Terracing Contour

planting Strip cropping

with cover crop Alley

cropping, agroforestry

Windbreaks or shelterbeds

Conservation-tillage farming

No-till Minimum

tillage

Identify erosion hotspots

Poor cultivation and prolonged drought

Plowing prairie dug up root system

Severe wind erosion

Largest internal migration from the Midwest

Soil Erosion Act 1935

Organic fertilizer Animal manure – dung , urine Green manure – freshly cut, growing green

vegetation Compost microorganisms to break down organic

waste Commercial inorganic fertilizer active ingredients

Nitrogen Phosphorous Potassium

Crop Rotation

Soil salinization Prevention Clean-up

Desertification, reduce Population growth Overgrazing Deforestation Destructive forms

of planting, irrigation, and mining

Reduce irrigation

Switch to salt-tolerant crops (such as barley, cotton, and sugar beet

Flush soil (expensive and wastes water

Stop growing crops for 2–5 years

Install underground drainage systems (expensive)

Open-ocean aquaculture – US developing, raising large carnivorous fish in underwater pens

located 300 Km offshore. Fish fattened with fish meal

Raising shrimp far inland in zero-discharge freshwater ponds to minimize damage to Florida coastal areas: salmon, trout, tuna, grouper, cod

Choose herbivorous fish – carp, tilapia Polyaquaculture : raise fish, shrimp, algae, seaweeds

and shellfish coastal lagoons

Shift to more grain-efficient forms of protein

Shift to farmed herbivorous fish Develop meat substitutes; eat less meat Whole Food Markets: more humane

treatment of animals World Organization for Animal Health –

humane transportation and slaughter of livestock animals

People food habits changing – eating lower down on the food chain

Paul Mader and David Dubois 22-year study Compared organic and conventional farming

Benefits of organic farming little or no use of synthetic pesticides,

fertilizers or genetically engineered seeds, fields free for 3 years

livestock raised without genetic engineering

Strategies for more sustainable agriculture Research on organic agriculture with

human nutrition in mind Show farmers how organic agricultural

systems work Subsidies and foreign aid Training programs; college curricula

Fig. 12-32, p. 308

SOLUTIONS

Organic Farming

Improves soil fertilityReduces soil erosionRetains more water in soil during drought years

Uses about 30% less energy per unit of yield

Lowers CO2 emissionsReduces water pollution by recycling livestock wastes

Eliminates pollution from pesticidesIncreases biodiversity above and below ground

Benefits wildlife such as birds and bats

Effect of different fertilizers on nitrate leaching in apple trees calcium nitrate and alfalfa residues,

composted chicken manure, integrated approach (combined)

Less nitrate leached into the soil after organic fertilizers were used – 4.4 to 5.6 times less

Polycultures of perennial crops

Wes Jackson: natural systems agriculture benefits No need to plow soil and replant each year Reduces soil erosion and water pollution Deeper roots – less irrigation needed Less fertilizer and pesticides needed

Annual Wheat Crop

Plant

Roots of a tall grass prairie

plant

Better at using water and nutrients

Supports local economies Does not have to be transported far –

reduces greenhouse gas emissions, 5 to 17 times less

Reduces environmental impact on food production – grow organic food or buy organic food grown locally

Community-supported agriculture (CSA)

Modern industrial agriculture ……………. depends on nonrenewable fossil fuels too little recycling of crop and animal wastes accelerates soil erosion does not preserve agro biodiversity destroy or degrade wildlife habitat disrupt natural species interactions that help

to control pest population sizes

rely more on solar energy than oil sustaining nutrient cycling by soil

conservation and by returning crop residues and animal wastes to the soil

sustain natural /agricultural biodiversity by relying on a greater variety of crop and animal strains

controlling pest populations broader use of polyculture and IPM