Where does our food come from?Where does our food come from?

• Croplands (mostly grain) – provide 77% of the world’s food

• Rangelands (meat) supply 16%• Oceanic fisheries (fish and

shellfish) – 7%

How Is Food Produced?How Is Food Produced?

• Sources of food• Primary plants: Wheat, corn, and rice• Primary animals:

fish, beef, pork, and chicken

• 14 plant and 8 animal species provide 90% of the global food calories

Major Types of AgricultureMajor Types of Agriculture

• Industrialized agriculture• Large amounts of fossil fuel, water, fertilizer,

and pesticides to produce monoculture crops or livestock animals

• Plantation• Form of industrialized agriculture – single

ownership

• Traditional subsistence agriculture – Produce only enough for the family

• Traditional intensive agriculture– Increase outputs for profit

Industrialized Agricultural Wastes and Land PollutionIndustrialized Agricultural Wastes and Land Pollution

• Animal Confinement– Waste runoff

• Overgrazing– Increases soil erosion

• Sedimentation• Nutrient application• Irrigation • Pesticides

Waste runoff increases nutrientsand pathogens in streams

Overgrazing typically strips the land of any natural protection and leaves the soil very susceptible to erosion

Overgrazing typically strips the land of any natural protection and leaves the soil very susceptible to erosion

Runoff carries sediments, nutrients and pesticides into streams that damagesfish habitat

Agriculture alters native habitatsand reduces native biodiversity

Major Types of AgricultureMajor Types of Agriculture

• Plantation - Form of agriculture that involves concentrated ownership of land with the means of production in the hands of one family or corporation, the use of hired labor, and mono-crop production for sale.

• Cash crops mostly for sale in developed countries• Bananas, coffee, soybeans

Traditional

Industrialized

Plantation

World Food ProductionWorld Food Production

Industrialized

Traditional

Producing Food by Green-Revolution TechniquesProducing Food by Green-Revolution Techniques

• Since 1950, increase in global food production has come from increased yields per unit area of crop land.

Producing Food by Green-Revolution TechniquesProducing Food by Green-Revolution Techniques

• Green revolution involves three steps:

1. High-input monoculture using selectively bred or genetically-engineered crops

2. High yields using high inputs of fertilizer, extensive use of pesticides and high inputs of water

3. Multiple cropping – increase the number of crops grown per year on a plot of land.

Green RevolutionsGreen Revolutions

First green revolution(developed countries)First green revolution(developed countries)

Second green revolution(developing countries)

Second green revolution(developing countries)

Major International agricultural research centers and seed banksMajor International agricultural research centers and seed banks

Interplanting – simultaneously grow several crops on the same ground. Reduces chance oflosing year’s crop to pests, bad weather, etc.

Producing Food by Traditional Techniques

Producing Food by Traditional TechniquesProducing Food by Traditional Techniques

• Types of Interplanting– Polyvarietal cultivation – planting several varieties

of the same crop– Intercropping – grow two or more different crops

at the same time (grain+nitrogen fixing plant)– Agroforestry (alley cropping) – crops and trees are

grown together– Polyculture – many different types of plants that

mature at different times are grown together

Causes of Soil ErosionCauses of Soil Erosion

•Wind•Water•People – farming, logging,

construction (or any activities that weaken root strength)

•Wind•Water•People – farming, logging,

construction (or any activities that weaken root strength)

Soil erosion in a wheat field

Areas of serious concern

Areas of some concern

Stable or nonvegetative areas

Global Soil ErosionGlobal Soil Erosion

Soil Degradation on Irrigated LandSoil Degradation on Irrigated Land

• Salinization • Waterlogging

EvaporationTranspiration

Evaporation

Waterlogging

Less permeableclay layer

Reducing and Cleaning Up SalinizationReducing and Cleaning Up Salinization

•Reduce irrigation•Switch to salt-tolerant crops•Flush soils•Not growing crops for 2-5 years• Install underground drainage

•Reduce irrigation•Switch to salt-tolerant crops•Flush soils•Not growing crops for 2-5 years• Install underground drainage

Saltwater and drainage is a continual problem for lowland agriculture near Puget Sound.

Tidegate – lets water out, but not back in.

Solutions: Soil ConservationSolutions: Soil Conservation

Soil RestorationSoil Restoration

• Organic fertilizer• Animal manure• Green manure – fresh cut

vegetation• Compost• Crop rotation – legume crops add

nitrogen to soil• Commercial inorganic fertilizer

Catching and Raising More FishCatching and Raising More Fish

• Fisheries• Fishing methods• Overfishing • Commercial extinction• Aquiculture• Fish farming and ranching

Pesticides: TypesPesticides: Types

• Chemicals that kill undesirable organisms

• Insecticides - insects• Herbicides - plants• Fungicides - fungus• Rodenticides - rodents

First Generation PesticidesFirst Generation Pesticides

• Primarily natural substances • Sulfur, lead, arsenic, mercury • Plant extracts: nicotine, pyrethrum

Second Generation PesticidesSecond Generation Pesticides

• Primarily synthetic organic compounds

• Broad-spectrum agents – toxic to many species

• Narrow-spectrum agents – toxic to few species

• Persistence in the environment

The Case for PesticidesThe Case for Pesticides

• Save human lives – spread of disease• 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

Characteristics of an Ideal PesticideCharacteristics of an Ideal Pesticide

• Affects only target pests• Harms no other species• No genetic resistance• Breaks down quickly in the

environment• Be more cost-effective than doing

nothing

The Case Against PesticidesThe Case Against Pesticides

• Genetic resistance • The pesticide treadmill – pay more for less

effect• 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

Bioaccumulation and BiomagnificationBioaccumulation and Biomagnification

• Persistent (non-biodegradable) toxins build up in an animal over time = bioaccumulation

• Become more concentrated at higher trophic levels = biomagnification

Integrated Pest ManagementIntegrated Pest Management

• Ecological system approach• Reduce pest populations to economic

threshold• Field monitoring of pest populations• Use of biological agents – natural

predators, parasites, disease• Chemical pesticides are last resort

Why is Integrated Pest Management not More Widely Used?Why is Integrated Pest Management not More Widely Used?

• Requires expert knowledge

• Slower than conventional pesticides

• Initial costs may be high

• Hindered by pesticide industry

• Requires expert knowledge

• Slower than conventional pesticides

• Initial costs may be high

• Hindered by pesticide industry

Solutions: Sustainable AgricultureSolutions: Sustainable Agriculture

• Low-input agriculture

• Organic farming

• Profitable

• Increasing funding for research in

sustainable techniques