Chapter 12

Food Resources

Nutritional Deficiencies

• Undernutrition: less than 90% of minimum calories(serious if under 80%)

• Malnutrition: deficient in protein + nutrients

• Marasmus: low calories and protein (age 0-1)

• Kwashiorkor: very low protein (age 1-3)

Macronutrient Deficiencies

Vitamin A (carrots)• affects 124 million children: blindness, reduces

resistance to diarrhea

• gene splicing: beta carotene rich variety of rice

(golden rice)

Iron (spinach)

needed for hemoglobin--> anemia

Iodine (seafood)

deficiency leads to goiter, enlargement of thyroid

Key Nutrients for a Healthy Human Life

12-2 How Is Food Produced?

• Concept 12-2A We have sharply increased crop production using a mix of industrialized and traditional agriculture.

• Concept 12-2B We have used industrialized and traditional methods to greatly increase supplies of meat, fish, and shellfish.

Traditional Foods

• Three systems produce most of our food– Croplands: 77%– Rangelands, pastures, and feedlots: 16% (using

29% of world’s land area)– Ocean fisheries and aquaculture: 7%

• Importance of wheat, rice, and corn – Provide a little less than half of calories and

protein– Monoculture problems

Food Production

• Has increased tremendously

• Technology– Increased use of tractors, farm machinery, and

high tech fish equipment– Inorganic fertilizer, pesticides, irrigation, high

yield crops– Raising fish, poultry and livestock in factory

like conditions (CAFOs)

Changes in Food Supply System

CroplandsProblems

– Environmental degradation

– Pollution

– Water shortage

Changes in Food Supply System

• Rangelands

Problems– Overgrazing

Changes in Food Supply System

Fisheries

Improvements– High tech fishing boats

(radar, nets)

- Aquaculture ponds

Problems- Overfishing

Major Types of Food Production

• Crop growth replaces late-successional community with early-successional community (usually monoculture)

Major Types of Food Production

• Industrialized (high-input) agriculture– 25% of all cropland– plantation agriculture

• common in tropical developing countries• produces cash crops

e.g. sugarcane, coffee, bananas

Major Types of Food Production

– Greenhouse food production• Used in arid areas• Requires diversion of water• Hydroponics (no soil) uses recycled water,

so more efficient

Spain Greenhouses

• Between 1974 and 2000, Spain built 118 dams as part of 22 water diversion projects to support greenhouse agriculture

Fig. 12-4a, p. 280

Fig. 12-4b, p. 280

2nd Major type of Food Production

• Traditional agriculture– feeds 42% of world

• Traditional subsistence– uses humans and draft animals to feed family – Shifting agriculture, nomadic livestock herding

• Traditional intensive agricultureincreased input: labor, water, fertilizer

More Traditional Ag

• Polyculture– Several crops on same plot– Polyculture provides habitat for pest predators– Crops mature at different times

e.g. Slash and burn agriculture• Leave abandoned plot fallow for 10 – 30 years

• Ashes fertilize

Agriculture and Environmental Problems

• Soil erosion

• Desertification

• Salinization and waterlogging

• Water shortages

• Loss of wild species

• Global warming

Soil Formation and Generalized Soil Profile

Science Focus: Soil Is the Baseof

Life on Land• Soil composition• Soil formation• Layers (horizons) of mature soils

– O horizon: leaf litter– A horizon: topsoil– B horizon: subsoil– C horizon: parent material often is bedrock

• Soil erosion• Hundreds of years to produce an inch of soil

First Green Revolution

A. Developed countries, 1950-1970B. Greatly improved productionC. 3 steps

1. Use high yield crops (monoculture)2. Use large amounts of fertilizer, pesticides, and

water3. Increase frequency of planting (multicropping)

2nd green revolution

• Began in 1967

• Dwarf varieties for tropics

• Fast growth

• High input: water, chemicals, oil

• Conserves forest, grassland, etc

Impact of 2 Green Revolutions

• Overall food production tripled (1950-1996)– per capita food prod up by 31% (1961 to 1985)

– World Bank: food price in 2000 was 1/3 food price in 1957 (taking inflation into account)

• Per capita increased, then decreased since 1985– lower price?, limits on high input crops b/c of

erosion?, etc

Agribusiness in U.S.

1. 650,000 farmers (2% of population) a) 9% of population is part of ag system,

from growing to market2. Biggest industry in US (18% of GNP)

Agribusiness in U.S.

3. In US, 2% income on food vs 40-70% developing

- rise in corn prices hurt developing countries - 2% above includes external costs of subsidies, taxpayer cleanup

Agribusiness in U.S.

4. Overall: 1 unit food energy = 10 units fossil fuel in growing, harvesting, transporting to store,refrigerating, cooking

Food travels an average of 1300 mi from field to plate

Video

• http://www.youtube.com/watch?v=AEINuCL-5wc&feature=related

• file:///Volumes/Miller_3B_PL/Media/LITE/PowerPoint_Lectures/chapter12/videos_animations/transgenic_plants.html

Meat Production and Consumption Increased

• Animals for meat raised in– Pastures– Feedlots and CAFOs

• Meat production increased fourfold between 1961 and 2007

• Demand is expected to go higher

Industrialized Meat Production

Fish and Shellfish Production Have Increased Dramatically

• Aquaculture (blue revolution)– Worlds fastest-growing type of food production

• In 2006, aquaculture produced 43% of all fish consumed

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

• Polyaquaculturefarm waste to fertilize ponds for phytoplankton food

Aquaculture

• Fish and shellfish• China produces 62% of output• Fish farming: raising fish under controlled

conditions• Fish ranching: hold, release anadromous fish, catch

when they return to spawn

Aquaculture

• China has developed fish polyculture– 4 species of carp feed at different trophic levels

• Aquaculture produces– 90% oysters, 40% salmon, 50% shrimp, prawn– 65% of freshwater fish worldwide– Catfish is leading US aquaculture product

Aquaculture

• Pros: little space, saves conventional fisheries

• Cons: large output of waste, disease spreads, Mangroves are cleared to raise shrimp (Indonesia)

Fig. 12-8a, p. 285

140

120

100

80Wild catch

Cat

ch

(mil

lion

s of

met

ric

tons

)

60

40

20 Aquaculture

0

1950 1960 1970 1980 1990 2000 2010

Year

Total World Fish Catch

Environmental Problems of Food Production

• Erosion– Wind and water– Reduces fertility, sedimentation

• Desertification– definition

Irrigation

– 20% of world’s cropland is irrigated– Salinization– Waterlogging

• Sometimes results from attempt to counteract salinization

Pros and Cons of GMFs

• Pros

• Cons

Food Distribution Problems

• Poverty– 80% of all malnourished children live in

countries with enough food to feed them

• Political corruption

• Inadequate storage facilities

Rangeland and Pastures

• Rangeland (40% managed by BLM)

• Pasture (managed or enclosed)

• Overgrazing (metabolic reserve)

• Compaction

• Nomadic herding

• Riparian zones

• Feedlots

Sustainability

• Sustainable yield is hard to establish• Overfishing may lead to commercial extinction,

e.g. orange roughy• 11 of 15 most important fisheries are overfished

(cod off Cape Cod, salmon in Washington and Oregon)

• Over 100 international fishery disputes• Global warming: degrade coral reef• Ozone depletion: increased UV penetration

Pests

• Compete with humans for food

• Invade lawns and gardens

• Destroy wood in houses– Spread disease

• Are a nuisance

• May be controlled by natural enemies

Pesticides

• Types of Pesticides

• Pros and Cons of Pesticide Use

• Pesticide Legislation

• Pesticide Alternatives

Pesticides: Types

First Generation Pesticides

• Derived from plants (coevolution)

• Plant extracts– Nicotine, pyrethrum (from the head of a

chrysanthemum), and rotenone (from root of rainforest legume)

• Sulfur, lead, arsenic, mercury

Second Generation Pesticides

• Primarily synthetic organic compounds

• Broad-spectrum agents

• Narrow-spectrum agents

• Persistence in the environment

The Case for Pesticides

• Save human lives

• Increase food supplies and lower costs

• Work better and faster than alternatives

• Health risks may be insignificant compared to benefits

• Newer pesticides are becoming safer

• New pesticides are used at lower rates

The Case Against Pesticides

• Genetic resistance

• The pesticide treadmill

• Can kill non-target and natural control species

• Can cause an increase in other pest species

• Pesticides do not stay put

• Can harm wildlife

• Potential human health threats

Characteristics of an Ideal Pesticide

• Affects only target pests

• Harms no other species

• No genetic resistance

• Breaks down quickly in the environment

• More cost-effective than doing nothing

Pesticide Regulation in the United States

• Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA)

• EPA Evaluation of chemicals

• Tolerance levels

• Inadequate and poorly enforced

• Food Quality Protection Act

Other Ways to Control Pests

• Economic threshold

• Adjusting cultivation practices

• Use genetically-resistant plants

• Biological pest control

• Insect birth control

• Hormones and pheromones

• Hot water

• Ionizing radiation

Integrated Pest Management

• Ecological system approach

• Reduce pest populations to economic threshold

• Field monitoring of pest populations

• Use of biological agents

• Chemical pesticides are last resort

Effects of IPM

TimeTime

Pes

t den

sity

Pes

t den

sity

Original pest population

Introductionbiological control

Equilibriumposition

Equilibrium position

Reduced pest population

Economic threshold

Fig. 20.7, p. 507

Why is Integrated Pest Management not More Widely Used?

• Requires expert knowledge

• Slower than conventional pesticides

• Initial costs may be high

• Hindered by government subsidies

Government Assistance

• Presently, keeps food prices low– Good for consumers, bad for farmers

• Gives farmers subsidies– $100 billion in US, keeps prices low but may

inhibit production in developing countries

• Eliminate price controls and subsidies?– If prices rise too high, hurts poorSubsidies for good behavior?

Interplanting(more than one crop on same plot)

1) Polyvarietal cultivation -One plot, varieties of same crop

2) Intercropping

one plot, 2 or more different crops

3) Alley cropping

Crops and trees together

4) Polyculture

Different crops with different yield times, different root depths

Soil Degradation

1. erosion

a) water and wind

b) sheet, rill, gully

c) worldwide impact (Madagascar, Haiti)

Soil Degradation

2. desertification

a) 10-50% loss of productivity

b) due to:

- overgrazing, deforestation - surface mining, soil compaction

- salinization, waterlogged soil - farming on unsuitable land

Soil Conservation1. reduces erosion and increases fertility

2. conventional tillage

3. no-till farming

a) used on 40% of cropland in US

No Till Farming

• http://www.youtube.com/watch?v=fLX3LWyl1AU&feature=related

Soil Conservation

4. terracing

a) steep slopehttp://www.youtube.com/watch?v=lNMCxUuF3q0&feature=related

http://www.youtube.com/watch?v=lNMCxUuF3q0&feature=related

5. contour farming

a) gentle slope

Soil Conservation

6. strip cropping

a) row crop and ground cover

7. alley cropping

a) crops and trees

8. windbreaks

a) reduce wind erosion

FertilizerOrganic

a)animal manure (improves structure, bacteria)

b)b) green manure (plow plants into soil)

c) compost (aerates soil, improves water and nutrient holding capacity, provides nutrients)

d) crop rotation

Fertilizer

inorganic

a) easy to transport and store

b) important part of the “green revolution”

c) problems (no organic component, compaction, salinization, runoff)

Sustainable Future

• Low input (organic) farming and high input monoculture

• Problems:– resistance from currently successful farmers– Low input technique has a steep learning curve– Without subsidies, full cost (higher) prices

passed on to consumer