Food for the Masses: Modern AgricultureFood for the Masses: Modern Agriculture

Myth of the Family Farm

Intensification of Agriculture

• Myth of the small family farm• Modern agriculture is industrial• need to feed a growing population• Need for ways to grow higher yields of food, fuel,

and fiber from a given amount of land, water, and labor

• Limits to production: physical and environmental factors that limit crop growth

• Modern agriculture has extensive environmental impacts

What is needed to produce food?

• Land• Water • Energy (fuel)• Do other substances increase yield?

– Pesticides, GMOs, herbicides, fertilizer

How Many People Can the Earth Feed?

• Thomas Malthus (1798)– Human population increases at a geometric

(exponential) rate, while food supplies grow at an arithmetic rate

– all living creatures increase beyond their available resources

– Food scarcity would eventually limit population growth (poverty, disease, war, famine, etc.)

Is Malthus right?

• Agricultural productivity (amount of harvested biomass) has been enhanced

• world food production has in fact kept up with rapid population growth. Gains have been especially dramatic in the past 50 years

Meeting the Needs of a Growing Human Population

•Rapid growth in demand for ecosystem services between 1960 and 2000:

– world population doubled from 3 to 6 billion people– global economy increased more than sixfold

•To meet this demand:– food production increased 2 ½ times– water use doubled– wood harvests for pulp and paper production tripled– timber production increased by more than half– installed hydropower capacity doubled

Food Production Trends

– Food production has more than doubled since 1960

– Food production per capita has grown

– Food price has fallen

But at what cost?

• Serious environmental and human health costs – reduced biodiversity– fragmented natural ecosystems – diverted or polluted fresh water resources – altered the nutrient balance of adjacent and

downstream ecosystems– consumes major amounts of energy and

generates greenhouse gas emissions that contribute to global climate change

What land is suitable for agriculture?

• In 2000, 37% all Earth’s land used for agriculture.– 11% used for crops– Rest used for pastureland (includes cultivated or wild

forage crops for animals and open land used for grazing)– Estimated ¾ Earth’s land surface is unsuitable for raising

crops without irrigation. Most of the remainder is subject to some soil, terrain, and/or climate limitations.

– only about 3.5 percent of Earth’s surface is suitable for agriculture without any physical constraints

Recent Changes in Agric. Land Use

• In regions where productivity is rising faster than demand, (US, EU, Japan), land is being withdrawn from cultivation.

• These areas rely on agricultural intensification to keep output high as their farmed lands shrink. – intensification has serious environmental impacts

• In contrast, land is being converted for agriculture in many parts of the developing world. – major cause of deforestation. Clearing forests for

agriculture alters ecosystems that provide important services such as sequestering carbon or absorbing floodwaters.

Summary statistics of agriculture in the US at the beginning and end of the 20th century

Intensification of Corn

• % of land area in each county that is cropland (left) and corn harvested for grain (right).

• Corn harvested for grain occupied ~23% of US croplands in 1900 and 17% in 2002

• Corn was grown throughout the midwestern and southeastern US in the early 1900s, today, these efforts are primarily concentrated in the Midwest.

Conversion to Agriculture leads to land degradation

Limpopo region, South Africa

Key Inputs for Photosynthesis

CO2 + H2O + sunlight → (CH2O)n + O2

Drought is the biggest limit on agricultural productivity because plants need an enormous amount of water.

When plants photosynthesize, they use energy from sunlight to convert carbon dioxide (CO2) and water into carbohydrates (plant tissue).

it might appear that plants would need equal amounts of water and CO2, but the actual ratio is approximately 400 to 1

Why do plants need so much water?

How Plants Use Water• 98% of a plant's water intake passes up from roots

to leaves and evaporates, exiting the leaf as water vapor through pores in the leaf surface called stomata.

• Movement of water from the soil to the atmosphere through the bodies of plants is called transpiration.

• Transpiration has important functions: 1. it carries minerals from the soil to the leaves 2. prevents leaves from overheating 3. most importantly allows uptake of CO2 from the

atmosphere.

Irrigation

• 1/3 global food harvests from irrigated areas (16% of total world cropland).

• Every year, humans divert about 2,700 cubic kilometers of water (5x annual flow of the Mississippi River) for crops.

• Allows Egypt to produce agriculture, and greatly expands grain production in northern China, northwest India, and the western Great Plains of US

• Impact: depletes normal river flows or contributes to salinization of agricultural lands

Satellite image of crop circles near border of Egypt and Sudan irrigated from aquifer

Fertilizer

• Plants need N for proteins• Many crop plants quickly deplete N from soils • Other sources of N:

1. manure, 2. naturally occurring N deposits (saltpeter) in mines,3. guano (seabird droppings) along the coasts of Chile

and Peru and Pacific islands 4. Commercial fertilizer after WWI

Seabird manure, a rich source of nutrients, has been used as fertilizer for centuries.

History of Synthetic Fertilizer• 1908 Fritz Haber- Haber-Bosch process (N and H gases combined

to produce ammonia (NH3) then nitrate). • used in WWI and WWII to make nitric acid for munitions. • launched the fertilizer industry• widespread use after WWII, boosted crop productivity• Impact:

– Requires large amount of energy: high temp, pressure to break bonds in N gas

– Fertilizer not taken up by plant roots washes into water bodies and ground water, altering the species composition and nutrient balance of downstream ecosystems. Can cause dead zones.

– problem is severe early in the growing season– Mismanaged livestock manure (discussed in section 6) causes

similar problems

Increasing Yield

• Agricultural ecosystems are unbalanced; inputs ≠ outputs (compare to natural ecosystem)

• Yield = product that can be harvested from an agricultural system

• increase yields by adding energy & materials, increasing the efficiency of energy conversion (what does that mean?) and allocation to the harvested product (?), or by reducing losses during the growing process.

• Agricultural yields have risen steadily throughout the history of human cultivation, but especially through the 20th century.

• Cereals are the primary source of animal feeds and non-meat calories for humans worldwide.

Yield• Productivity = farmers' total output per unit of land• Huge increase in productivity recently due to intensification

– Land and labor inputs decreased – irrigation, synthetic fertilizers, pesticides and herbicides, and

mechanization increased– Scientific advances (higher yielding crop varieties, new strains

easier to harvest, more durable during transport, and longer-lasting in storage

– MOST IMPORTANT: increasing the harvest index (the ratio of harvested (edible) biomass to total biomass).

– "Green Revolution"— 1940s, 30 y transformation of agriculture in developing regions; distribution of high-yielding crops, fertilizer, irrigation, and pesticides to subsistence farmers in Asia and Latin America

Harvest Index Example: Rice

New Efficiencies Lead to New Problems

• Green Revolution helped world food production increase faster than population growth from 1950 onward.

• However, relied on synthetic fertilizer and irrigation• new plant varieties were not inherently high-yielding (i.e. not

able to use resources more efficiently than traditional varieties) and likely would have done worse under "natural" conditions.

• highly susceptible to pests and diseases, required heavy use of pesticides

• new plants were short, more susceptible to competition from weeds, so farmers also had to use herbicides to raise them (affects non-target plants)

Pesticides • Monoculture -planting large holdings of one or a few high-

yield crop varieties • Increased efficiency (mechanized cultivation, harvest• vulnerable to pests and pathogens because nutrient-rich and

no natural protection from genetic diversity • many pest species spread rapidly in ecosystems where

disturbances (plowing) have eliminated natural predators• Pesticides are effective but often cause health problems• organochlorines (DDT, etc)

– cause human health effects (dizziness, seizures, respiratory illness, and immune system dysfunction);

– reduced Bald Eagle popultions; – most are now banned in US

• Newer pesticides less toxic (but still toxic) and many pests become resistant to them

Alternatives to Pesticides and Herbicides

• releasing natural insect predators or• breeding resistance into crops (some corn seeds

engineered to resist certain pests) • integrated pest management -farmers consider each

crop and pest problem as a whole and design a targeted program drawing on multiple control technologies, including pesticides, natural predators, and other methods.– Rice in Indonesia

Example of Integrated Pest Mgt

• 1986, IPM in Indonesia to control the planthopper (lays eggs inside rice plant stalks)

• Farmers monitored fields for planthoppers and their natural predators, treated outbreaks using minimal pesticides or biological controls

• rice production increased by 15%, while pesticide use fell by 60%

Best/Worst Produce with PesticidesDirty Dozen (buy these organic)1. Peach2. Apple3. Bell Pepper4. Celery5. Nectarine6. Strawberries7. Cherries8. Kale9. Lettuce10.Grapes (Imported)11.Carrot12.Pear

Clean 15 –lowest in pesticides1. Onion2. Avocado3. Sweet Corn4. Pineapple5. Mango6. Asparagus7. Sweet Peas8. Kiwi9. Cabbage10. Eggplant11. Papaya12. Watermelon13. Broccoli14. Tomato15. Sweet Potato

Livestock

• monoculture farmers raise one or a few animal strains bred to maximize output (hens that lay more eggs, dairy cows that produce more milk, etc.)

• Technology -antibiotics and hormone treatments, to make animals grow larger and more quickly

• animals confined indoors instead of letting them range (cheaper and ‘more efficient’)

• global meat and dairy production predicted to double between 2000 and 2050

• Major environmental impacts

Problems with Feedlots• Crowding stresses animals, promotes disease • Antibiotics to treat and prevent illnesses, promote growth are

identical or similar to antibiotics used in humans, • promotes drug resistant bacterial strains that can infect humans

through the food chain or via direct exposure • massive quantities of animal waste:

– One cow can produce >40 lbs manure per day. – Many store millions of gallons of manure in tanks or lagoons

until it can be used on neighboring fields.– Risk of leaking or spillover, polluting waterways with excessive

nutrients, antibiotics, hormones• produce air pollutants that are significant hazards at scales ranging

from local to global• generates 18% of world greenhouse gas emissions • accounts for 8% of world water use, • probably the largest water pollution source

Genetic Improvement

• selective breeding –breeding plants/ animals to select for desirable traits– Relies on traits existing in nature

• GMOs (genetically modified organisms)– More precise modern– Can use DNA sequences from different species (Ex: ‘Bt

corn’ has a gene from the bacterium Bacillus thuringiensis that kills insects

– Varieties developed to tolerate herbicides (more than 80% US soybeans are Round-up Ready).

• USDA has approved 63 genetically engineered crops, including corn, soybeans, cotton, potatoes, wheat, canola, and papaya

• AKA ‘transgenic’ plants

GMOs

• golden rice, several genes have been added so that the plant produces betacarotene (vitamin A) in its grains

• Helps reduce Vit A deficiencies from diets based on conventional rice

• What’s wrong with traditional approach of a balanced diet?

Problems with GMOs

• potential harm to nearby ecosystems and the possibility that GMO crops or animals will hybridize with and alter the genetic makeup of wild species– Ex: genes from high-yield GMO crops could give wild

plants qualities that make them more weedy and invasive• Human health effects unknown• Hard to predict• Food containing GMOs unlabeled (organic food does

not contain GMOs)

Agriculture and Energy• use energy directly to heat and cool buildings, operate equipment,

pump irrigation water, and transport products • indirectly uses energy to make fertilizer (natural gas) and pesticides

(petroleum and natural gas). • Most energy-intensive: Raising livestock on grain

– consumes fossil fuel to make pesticides and fertilizers to grow feed crops.

– Fattening one steer on corn to market weight can consume the equivalent of 35 gallons of oil

– inefficient because animals convert only a fraction of the energy in their feed grain to growth

– 2 kg of grain to produce 1 kg poultry, – 4 kg grain to make 1 kg pork– 7 kg grain to produce 1 kg of beef

• Food processing and long-distance shipment consume additional energy.

Future of Food• As we produce more food, do we sacrifice

quality?– Ex: corn-fed livestock

• Higher in saturated fat• Increased incidence of toxic E. coli strain O157:H7• Energy-intensive• Leads to cattle illness • Major environmental impacts

• What can we do to improve the quality of our individual diets?

10 Simple Tips to make positive changes to your eating habits and to our food system:

1. Stop drinking sodas and other sweetened beverages.You can lose 25 lbs in a year by replacing one 20 oz soda a day with a no calorie beverage (preferably water).

2. Eat at home instead of eating out.Children consume almost twice as many calories when eating food prepared outside the home.

3. Support the passage of laws requiring chain restaurants to post calorie information on menus and menu boards.Half of the leading chain restaurants provide no nutritional information to their customers.

4. Tell schools to stop selling sodas, junk food, and sports drinks.Over the last two decades, rates of obesity have tripled in children and adolescents aged 6 to 19 years.

5. Meatless Mondays—Go without meat one day a week.~ 70% of antibiotics used in the US are given to farm animals.

6. Buy organic or sustainable food with little or no pesticides.According to the EPA, over 1 billion pounds of pesticides are used each year in the U.S.

7. Protect family farms; visit your local farmer's market.Farmer's markets allow farmers to keep 80 to 90 cents of each dollar spent by the consumer.

8. Make a point to know where your food comes from—READ LABELS.The average meal travels 1500 miles from the farm to your dinner plate.

9. Tell Congress that food safety is important to you.Each year, contaminated food causes millions of illnesses and thousands of deaths in the U.S.

10. Demand job protections for farm workers and food processors, ensuring fair wages and other protections.Poverty among farm workers is more than twice that of all wage and salary employees.

What is organic?

• USDA certification standards adopted 2002• Organic Agriculture -"An ecological production management

system that promotes and enhances biodiversity, biological cycles and soil biological activity. It is based on management practices that restore, maintain and enhance ecological harmony." (USDA)

• Additional cost in buying organic food has decreased, but still more expensive than conventional food

• Health benefits from eating organic (to humans and environment) outweigh cost

USDA Organic standards

Organic standards prohibit:– Genetically modified organisms (GMOs), seeds or

ingredients – Bio-solids (sewage sludge) and synthetic fertilizers – Synthetic pesticides, herbicides or fungicides – Antibiotics or added growth hormones – Animal by-products in animal feed

Organic practices require:– Continual monitoring, maintenance and improvement of soil

health – Crop rotation, mulching and other practices to prevent soil

erosion and enhance soil health – Specific composting methods for both animal and plant waste – Outdoor access for livestock – Pasture for all ruminants – 100 percent certified organic feed for organic animals – Inspections of all farm fields, processing facilities and

production and sales records by agents accredited as USDA Certifiers

– Periodic testing of soil and water used in production No certification standards for fabrics, health supplements,

beauty products, household cleaners, pet foods, farmed or wild seafood.