AP ENVIRONMENTAL SCIENCEUnit 4: Feeding the World (Ch. 11)

Can we feed the world?What do we want to know?• Can we produce enough food?• Can we grow crops sustainably?• Can we produce crops without damaging

ecosystems?

What do we need to understand?• How crops grow and how productive they can be

Can we feed the world?• History show that agriculture has been the most

sustainable of all human activities.• Some regions have been farmed for thousands of

years (Nile Valley)

• Nomadic people would farm an area until it became degraded before moving on to leave the land fallow (plowed but left unsown to restore fertility)

• Farming has changed ecosystems

Can we feed the world?• History of agriculture is a series of human attempts to

overcome environmental limitations and problems.

• Each solution creates new problems

• Some side effects expected

• Multiple pressures have been put on agricultural land

Aswan Dam across the Nile River. First built in 1898,

latest project completed in 1970

Can we feed the world?• Agricultural Land is defined as any area devoted to

agriculture, the systematic and controlled use of living organisms (crop or livestock)

• Arable land- land used for producing crops requiring annual replanting• Permanent cropland- land used for crops that do not

require annual replanting• Pastures- natural or artificial grasslands used for livestock

grazing

Can we feed the world?• 36% of the world’s land

area is considered suitable agricultural land

• 1/3 (11%) of the land is arable

• Percentages of arable land vary by continent

Can we feed the world?• The role of agriculture in

ecosystems is changing with the needs of the human population

• Technology, irrigation, and genetically modified foods have changed the land area available for agriculture

Can we feed the world?

Can we feed the world?

•Other factors influence the production of crops even in places that contain arable land

• Social disruptions • Social attitudes• Economy• Weather

Can we feed the world?• The key to food production in the future:• Increased production per unit area• Requires increased use of water, fertilizers, and

pesticides• OR implementation of ecological principles in the use of

Organic/ BioDynamic farming• Utilizing marginal lands

Can we feed the world?• As increased production is demanded there will be

increased in environmental degradation

• Limiting factors to agricultural production include water needed for irrigation

Can we feed the world?

How we starve• People “starve” in two ways• Undernourishment- lack of sufficient calories in

available food. One has little or no ability to move or work and eventually dies from lack of energy.

• Malnourishment- lack of specific chemical components of food, such as protein, vitamins, or other essential chemical elements.

How we starve• Food emergencies affected 34 countries worldwide

at the end of 20th century

• Africa has the most acute food shortages

• Food distribution is a major problem

• World food aid does not meet all the caloric needs of people

*Best solution is to increase local production

How we starve• Currently, over 800 million people worldwide lack access to

adequate amounts of food

• 24,000 people starve to death each day (8.8 million/year)

• The primary reason for undernutrition and malnutrition is poverty

• Food aid focuses on providing food security (adequate access to safe and nutritious food) to all areas affected by chronic hunger

How we starve• Undernourishment manifests as famine• Obvious, dramatic and fast acting

• Malnourishment is long-term and insidious• May not die out right but suffer

impairments• Can result in brain damage in some

cases and overall less productive, weaker citizens in most cases (negative feedback loop)

How we starve• Major problems of undernourishment• Marasmus – progressive emaciation caused by

lack of protein and calories

• Kwashiorkor - a lack of sufficient protein in the diet

• Chronic hunger - enough food to stay alive but can not live satisfactory or productive lives

How we starve• In the Ga language of Ghana, kwashiorkor means

"the sickness of the child who is displaced from the breast”or “the disease of the displaced child"

• Kwashiorkor is an ailment that results from severe protein deficiency. It is mainly seen in the tropical and subtropical regions of west and central Africa. It commonly occurs when a child is weaned onto a diet deficient in protein after the birth of another child.

• A macronutrient disorder

How we starve• An equally troubling problem is overeating in some areas of

the world

• Highly processed foods rich in sugars and fats are becoming large parts of daily diets

• 64% of adult Americans are overweight- up from 40% just 10 years ago

• Overeating also causes trickle down effects in terms of healthful living and healthcare

How we starve• Americans spend $42 billion per year trying to lose weight.

• $24 billion per year is needed to eliminate world hunger.

How we starve

How we starve• World food production must provide adequate nutritional

quality as well as quantity. Is access to quality food a basic human right? (like clean air and clean water?)

What we eat and what we grow• Of Earth’s ½ million plant species• 3,000 agricultural crops• 150 species cultivated on large scale• 14 crop species provide most of the food

consumed in the world• 6 plants provide 80% of the total calories for ALL

humanity

What we eat and what we growWheat Rice Maize Potatoes Sweet

PotatoesManioc Sugarcane

Sugar Beet

Common Beans

Soybeans Barley Sorghum Coconuts Bananas

What we eat and what we grow• Forage - crops grown for domestic animals• 14 million acres of alfalfa in the US

• Domestic animals include• 14 billion chickens• 1.3 million cattle• ~1 billion each sheep, ducks and pigs• 700 million goats• 160 million water buffalo• 18 million camels

What we eat and what we grow• North Carolina crops and livestock products

Crops

• Tobacco• Cotton• Soybeans• Corn• Peanuts• Wheat

Livestock

• Hogs & pigs• Cattle & calves

• Poultry• Turkeys• Eggs

What we eat and what we growOther Commodities• Rangeland - provides food for grazing and browsing animals

without plowing and planting.

• Pasture- is plowed, planted and harvested to provide forage. It is often irrigated for maximum productivity

• Large world market for small grain crops (rice, wheat, soybeans).• Production increased from 1966-1996 but has been flat

since 1996

What we eat and what we grow• Most marine and freshwater food is obtained by hunting.• Sustainability – this is NOT sustainable

• Aquaculture- the farming of food in aquatic habitats• Used as an important protein source for many people,

especially in developing countries• Could be a solution to providing nutritional quality in

diets• A more sustainable solution to overfishing

What we eat and what we growAquaculture• Extremely productive on a per-area basis• Flowing water brings food into the pond from outside• Can exploit multiple niches in the pond• May be able to utilize waste products (treated sewage)

• Mariculture- the farming of ocean fish.• Oysters and mussel production has been on the rise and is

evident locally in Carlsbad on off shore in Ensenada

AgroecosystemsFarming can be considered a disturbance that changes natural ecosystems in 6 ways:

• 1. Controlled Succession • Farming attempts to stop natural succession and keep a system in the early stages of succession

• Requires planting crops on cleared land and continuous clearing of land to keep it clear of unwanted vegetation

Agroecosystems• 2. Monoculture• Farming often focuses on the production of just one

species or genetic strain of a species• The entire crop has similar genomes and therefore can

become susceptible to disease or environmental change that wipes out the whole crop• One species using the land for a period of time can reduce

vital nutrients from the system• Crop rotation, artificial fertilizers, or land left fallow can

return necessary nutrients to the soil

Agroecosystems• 3. Distribution• Farming plants crops in even rows and patterns to make

maintenance and harvesting easier• Even distribution makes it easier for pests to access crops

as an easy food source

Agroecosystems• 4. Biodiversity• Farming reduces biological diversity locally and globally

by focuses on just a few key species used in crop production• Pest control also reduces biological diversity by reducing

populations of agricultural pests that change the local food chain

Agroecosystems• 5. Plowing• Plowing causes disturbance in the soil that turns over the

soil at a specific depth

• Exposed soil is more susceptible to erosion and loss of chemical nutrients

• Land that has been plowed takes longer to recover when left to natural succession

Agroecosystems• 6. Genetic Modification• More recent techniques in increase crop production focus

on the creation of genetically modified species that can survive in harsher environments with less need for pest control

Limiting Factors• The process of agriculture requires large amounts of energy

that have to be sustained by an ecosystem

• The fossil fuel and human energy required per calorie of food produced is called energy subsidy• Small scale farm production has low energy subsidy while

large scale mechanized farming has high energy subsidy• The average U.S. diet has about a 10 calorie energy input

for every calorie you eat• Food choices are energy choices

Limiting Factors• High-quality agricultural soil has:• All the chemical elements required for plants• A physical structure that lets air and water move freely• Retains water well• Mixture of soil particles with various sizes

Limiting Factors• Liebig’s Law• Single factor determines the growth and therefore the

presence of a species

• Growth of a plant is affected by one limiting factor (plants can only grow as much as they have the most limiting nutrient present)

• 20 chemical elements are required plant nutrients

• Macro- and micro- nutrients

Limiting Factors• Two elements may have a synergistic effect• A change in the availability of one resource affects the

response of an organism to some other resource.

• Nutrients may become toxic when levels are to high (fertilizer burns and salting out from long term irrigation with high salt content water)

• Older soils more likely to lack trace elements due to leaching that occurs naturally over time

Future of Agriculture• Three major technological approaches to agriculture:

• 1. Modern mechanized agriculture

• 2. Resource- based agriculture• Organic food production

• 3. Bioengineering

Future of Agriculture• Mechanized Agriculture – demand based

Future of Agriculture• Resource based agriculture- biological technology applied

and conservation of land, water and energy emphasized

Future of Agriculture• Organic farming – no artificial chemicals (fertilizers or

pesticides), no genetic engineering, ecological control

History of Agriculture

10,000 years ago •Resource-based agriculture and what we now call organic agriculture were introduced

18th -19th century •A shift to mechanized, demand-based agriculture occurred during the Industrial Revolution

20th century •A return to resource-based agriculture began using new techniques

Today •growing interest in organic agriculture as well as use of genetically engineered crops

Green RevolutionName attached to the post WWII programs that have led to

the development of:• new strains of crops w/ higher yields• better resistance to disease • or better ability to grow under poor conditions

• Sometimes resulted in the application of large amounts of chemical fertilizers

• Was made possible by availability of large amounts of petroleum for making chemical fertilizers

Improved Irrigation• Better irrigation techniques could improve crop yield and

reduce overall water use by utilizing:

Drip irrigation Hydroponics

Organic Farming• Organic faming typically considered to have many qualities:• More like a natural ecosystem than monoculture• Minimizes negative environmental impacts• The food that results does not contain artificial

compounds• Taste better!!!!• Sustainable• Doesn’t expose workers to harmful chemicals

• One of the fastest growing sectors in US agriculture

Monoculture• Most farming practices employ the use of monoculture to

focus on just one species that they cultivate and harvest during a growing season

• Advantages:• Use of climate and pest forecasting to plant hybrids

resistant to obstacles predicted for the year• Increased crop production if predictions and hybrid growth

is as expected

• Disadvantage:• If predictions of climate and pests are incorrect crop

production can be very low

Polyculture• Planting a mixture of crops and/or a broad range of

genotypes in the same area• Gives lower average yearly production but reduces the

risk of very low production years.• Labor intense• Requires better education in ecology and Integrated Pest Management (IPM)

Productive Yields• Effective growth of any crop must take into account the

climate of the region and resources required to grow crops in areas they are not native to growing in

Eating lower on the food chain• Some people believe it is ecologically unsound to use

domestic animals for food.• Eating each step up the food chain leaves much less food

to eat per acre as a result of trophic level inefficiencies• Eating lower on the food chain conserves resources and

could increase the carrying capacity of an ecosystem

Eating lower on the food chain• There is value in rangelands that are better suited to

livestock production• These areas are often hilly or mountainous and therefore

susceptible to rapid erosion of their thin soils

Eating lower on the food chain• Another problem with the argument not to use domestic

animals in agriculture is that they are a major source of protein and minerals for many populations.

• Other factors:• Animals are still used for plowing (the entire Andean

Plateau agriculture is an example)• Carrying goods• Wool and leather – source of clothing • Fuel and fertilizer source (excrement)• Eventually these animals can be consumed

Eating lower on the food chain• The issue of whether or not to consume meat is an issue of

both science and values

• People can choose not to eat meat because of:• Specific dietary restrictions• Moral or ethical beliefs• Religious beliefs (Hinduism, Buddhism, etc.)

Genetically Modified Foods• Scientist have been able to transfer

specific genetic characteristics from one species to another

• Genetic engineering in agriculture involves several practices• Faster and more efficient ways to develop

hybrids• Introduction of the terminator gene• Transfer of genetic properties from widely

divergent kinds of life (antifreeze gene in fish to strawberries and tomatoes – is this a good practice?)

Genetically Modified Foods• Considerable interest in developing crops • With entirely new characteristics• E.g. nitrogen fixation

• With tolerance of drought, cold, heat and toxic chemical elements.

• Most genetic engineering of plants to date has involved making them either pest resistant, or herbicide resistant – not making them more productive to provide greater quantities of food to the people of the world

Climate change and agriculture• Climate change may increase or decrease yield depending

on the complex interaction between local weather, evapotranspiration, soil condition, and availability of fresh water

State of Agriculture Today• After the Green Revolution (1950-1990) crop production

tripled and per capita output rose to 36% while cost of production dropped by 1/3

• Since 1990 grain production leveled off and in the past decade has begun to drop

• Currently, the United States produces 17% of the world’s grain

State of Agriculture Today• In North America 24% of labor is involved in food growth

(not including processing and transport)• Only 0.3% of labor in the United States (9% total in the

food industry)• 45-65% of labor in developing countries

• Agriculture consumes 17% of all commercial energy in production and processing

• Solutions to energy use and employment suggest a move to smaller scale crop production focused on resource based techniques (concern- yield per acre)

Current Land Use

51%

6%

8%

11%

10%

14%

Unusable (Ice, Deserts, Mountains, etc.)

Arid

Tropical Forest CultivatedGrazed Forests, Arid

Potential for Grazing

Used for Agriculture

Potential for Cropland

State of Agriculture Today• Climate concerns predict a shift in the current land available

for natural cultivation to smaller and smaller bands of land with enough rain and temperatures that are moderate enough for most crops

• Where do we look next for land?• Potential land available in tropical and arid environments

• What will have to be done to the land to make it arable?• Irrigation, fertilizers, pesticides, equipment

State of Agriculture TodayUntapped resources• New crops not yet in production• Microlivestock (insects, etc.)• 58-78% protein content• 3-4 times the nutritional value of beef

• Advanced tissue culture• Transgenomics

State of Agriculture Today• Think about what you eat…• Where does it come from?• What processes are involved in production?• What has to be added that is not included naturally?

(Vitamin A, Iron, Iodine)