Transcript Chapter 14 Part 1 - Mr. Manskopf's Class
Food and Soil Resources
G. Tyler Miller’s Living in the Environment 14 th Edition
Chapter 14
Two Worlds
Soil, a limited resource we depend upon, but take for granted
Chapter 14: Key Concepts
Methods of producing food
Increasing food production
Soil degradation
Increasing sustainability
Aldo Leopold
There are two spiritual dangers in not owning a farm. One is the danger of supposing that breakfast comes from the grocery store, and the other that heat from the furnace.
Section 1: How Is Food Produced?
• What systems provide us with food?
• What plants and animals feed the world?
• What are the major types of food production?
How Food Is Produced
Historically: • Croplands (77%) • Rangeland (16%) • Ocean Fisheries (7%)
Since 1950 there has been a staggering increase in all production.
Huge technology increase
How Food Is Produced
Technology Changes:
• Farm machinery • Fishing equipment • Fertilizers • Pesticides • Irrigation • GE Foods • Feedlots • Fish farms
Each improvement brings new challenges
How Food Is Produced
Can we meet the challenge of feeding 9 billion people by 2050?
• W/O Degradation of environment • And reduce poverty (1 of 5 do not produce enough food)
How Food Is Produced
• 30,000 possible plant species people can eat • Since ag. rev. 10,000 consumed • Today: 14 plants, 8 terrestrial animals provide 90% calories • 3 (wheat, rice and corn) provide ½ world’s calories – all annuals (potatoes huge also) • Dramatic reduction in biodiversity of agriculture • Most cannot afford meat
How Is Food Produced?
Sources of food
3 Primary plants: wheat, corn, and rice
4 Primary animals: fish, beef, pork, and chicken
Major Types of Agriculture
Industrialized agriculture
Plantation
Traditional subsistence agriculture
Traditional intensive agriculture
Major Types of Agriculture
• • • • • •
Industrial Agriculture: Fossil Fuel Energy Heavy Water Use Single Crops (monoculture) Commercial fertilizers ¼ of all cropland Mostly in developed countries
Industrial agriculture in California
Major Types of Agriculture
Plantation Agriculture:
• Form of industrial agriculture in tropical developing countries • Cash crops: banana, coffee, sugar cane, cocoa • Monoculture for sale in developed countries • Increasing large livestock
Coffee Plantation
Major Types of Agriculture
Traditional Subsistence Agriculture: • Human labor and draft animals producing food form family survival • Nomadic herding • 42% of world’s people uses traditional agriculture
Major Types of Agriculture
Traditional Intensive Agriculture:
• Increasing human and animal labor, fertilizers, water to get higher yields • Enough food for family and to sell locally • Agriculture is world’s leading industry
World Food Production
Fig. 14-2 p. 275
Hunterdon County, New Jersey
Section 2: Producing Food by Green-Revolution Techniques
High-input monoculture
Selectively bred or genetically-engineered crops
High inputs of fertilizer
Extensive use of pesticides
High inputs of water
Multiple cropping
Green Revolution in Agriculture
Since the 1950s farmers having been getting huge increases in crop production per unit of land.
First Step: develop and plant monocultures of GM high-yield crops like corn, rice and wheat Cavendish Banana
Green Revolution in Agriculture
Second Step: Use large inputs of fertilizers, pesticides and water.
Third Step: Increase number of crops grown per year on a plot of land (more crop less land)
These techniques produce huge increases in crops BUT need lots of water, fossil fuels, machinery, pesticides, fertilizers * Uses 8% of world’s oil *
Green Revolution in U.S.
• • • •
Agribusiness: loss of the family farm to corporate farming…Superfarms U.S. Ag. More total sales than auto, steel and housing combined 18% of Gross National Income (1/5 of all U.S. private sector jobs) 0.3% of world’s farmers produce 17% of world’s grain (1/2 of world’s corn and soybeans) Huge increase in efficiency
Green Revolution in U.S.
Developed Countries: People spend about 40% of income on food Developing Countries: 70% Industrial Ag. Needs cheap fossil fuels…putting food on table accounts for 17% of energy used in U.S.
Energy used to grow, store, process, package, transport, refrigerate, cook 10 units of energy for 1 unit of food energy in your stomach
Green Revolutions
First green revolution (developed countries) Second green revolution (developing countries) Major International agricultural research centers and seed banks Fig. 14-4 p. 277
Producing Food by Traditional Techniques
Interplanting
Polyvarietal cultivation
Intercropping
Agroforestry (alley cropping)
Polyculture Look up terms on page 278
Showing where energy is used in food production in U.S. Food travels avg. of 1,500 miles from farm to fork in U.S.
New Jersey Peach Farm: What are the advantages and disadvantages of eating locally grown food?
Section 3: Soil Erosion
• What causes soil erosion?
• How serious of a problem is it?
• Good news and bad news from the U.S.
• What is desertification?
• How do salts degrade the soil?
Causes of Soil Erosion
Wind
Water #1
People Why care about soil erosion?
Impacts of Soil Erosion
• Loss of soil fertility • Sediment runoff causes problems in surface water (pollution, clog ditches, boat channels, reservoirs) • #1 source of U.S. water pollution • Renewable only on LONG timeframes (200-1,000yrs. for 1 inch)
Soil Erosion
On Ag. land in U.S. today, soil is eroding 16 times faster than it is created
Global Soil Erosion
Areas of serious concern Areas of some concern Stable or nonvegetative areas Fig. 14-7 p. 280
Soil Erosion in the US
Dust Bowl – 1930s: Fig. 14-5 p. 281
Reductions in erosion since 1987
1985 Food Security Act
Huge Erosion Problems During “Dust Bowl” era
Causes of Desertification
Overgrazing
Deforestation
Erosion
Salinization
Soil Compaction
Natural Climate Change Refer to Fig. 14-10 p. 283
World Desertification
Fig. 14-9 p. 282
Desertification: causes and consequences.
•
Occurring on 1/3 of world’s land
Salinization
1. Irrigation water contains small amounts of dissolved salts 2. Evaporation and transpiration leave salts behind 3. Salt builds up on soil
Reducing and Cleaning Up Salinization
Reduce irrigation
Switch to salt-tolerant crops
Flush soils
Not growing crops for 2-5 years
Install underground drainage Refer to Fig. 14-12 p. 283
Soil Degradation on Irrigated Land
Salinization
Waterlogging 1.
Precipitation and 2.
3.
irrigation water percolate downward Water table rises Bad for roots Evaporation Transpiration Evaporation Waterlogging Less permeable clay layer Fig. 14-11 p. 283
Section 4: Soil Conservation
• What is soil conservation and how does it work?
• What are some methods for reducing soil erosion?
• Inorganic versus organic fertilizers
Soil Conservation
Involves many ways of reducing soil erosion and restoring fertility to soil.
Conventional Tillage
Farmers plow the land and then break up and smoothes soil to make a planting surface
• Leaves soil vulnerable to erosion • Midwest tillage often down in fall (winter bare)
Conservation Tillage
Disturbing the soil as little as possible while planting crop
• Not tilling over winter • Planting without disturbing soil • Special equipment “inject” soil with seed, fertilizer etc.
• In 2003 45% of U.S. farms
Solutions: Soil Conservation
Conventional-tillage
Conservation tillage
Terracing
Refer to Fig. 14-14 p. 285
Contour farming
Strip and alley cropping
Windbreaks
Land Classification
Terracing Used on steep slopes Reduces erosion and water loss
Cover Crops: can be planted right after harvest to hold onto soil during winter
Contour planting
Planting crops in rows across the slope Strip Cropping Alternating crops from row crops and crops that completely cover surface
Alley Cropping:
several cops planted together in rows (alleys) Increases shade (less water) Provide windbreaks
Windbreaks
Soil Restoration
Organic fertilizer
Animal manure
Compost
Crop rotation
Commercial inorganic fertilizer
Organic Fertilizer
Has decreased in the U.S. due in part because most farmers no longer raise livestock and it costs too much to transport
•
Poop Factory and Phillies Soil
• Inorganic fertilizers have taken off
Inorganic Fertilizers
• • • •
Nitrogen, Phosphorous, Potassium Grown in usage worldwide Credited with increasing crop yields (1/4 of world crops) W/o could only feed 2-3 billion people Many problems associated (see next slide)
The amount of energy needed to produce a single hamburger is enough to power a small car 20 miles