Download Food and Agriculture

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Food and Agriculture
Big question: how do humans meet their nutritional needs
Bigger question: how do you answer the big question and not degrade the
environment
Sustainable agriculture
Nutrition
Average caloric need: 2200 cal/day
Food production is adequate
Barring disaster, food supplies will increase
Food distribution is problem
Food Distribution
 US, Canada, Western Europe, Australia—excess food for most
 Sub-Saharan Africa, portions of Mid-and Southeast Asia—most at risk for
chronic under and malnourishment
 Food security—ability to obtain sufficient food on daily basis
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Food Shortages
Famine—food shortages resulting in massive starvation
Surface cause—lack of rainfall, insect attack
Root causes—poverty, corrupt governments, political oppression & unrest,
greedy power elite, war, genocide, etc.
Food Shortages
Amartya Sen—conflict and oppression: roots of famine
Democratic countries with free press—no major famines
Locals usually know how to deal with temporary climate fluctuations
Conditions tend to stabilize
Food Shortages
Feeding camps—wrong way: dangerous and debilitating travel, crowded
conditions, poor water supply and sewage treatment, etc
People disrupted—no home, no jobs, no tools, no money, may not be able to
return home
Risk of permanent disruption
Food Shortages
Foreign assistance--wrong foods: for long term, storage and pest problems
Wrong technologies—too high tech or energy-intensive: need trained workers
and trouble shooters, reliable energy supply
Nutrition
Balanced diets: adequate calories and nutrients
Malnourishment—lack of certain nutrients in food or inability to absorb
Obesity—too many calories, sedentary life
Anemia—low hemoglobin, iron deficiency
Iodine-deficiency—(soils)
Nutrition
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Vitamin A—blindness, problem with starch-based (processed) food
Folic acid—neural tube defects
Protein—kwashiorkor: protein deficiency, red-orange hair, bloated bellies, etc.
Low cal., protein.—marasmus: shriveled up
Balanced Diet
Whole grains, unsaturated plant fats, legumes, nuts, vegetables, fruits, lean
meats: emphasized
Red meats, saturated fats, processed carbohydrates: decrease
Major Food Sources
Grains: wheat, rice, corn, barley, oats (grasses)
Root crops: cassava, sweet potatoes, potatoes
Legumes: beans, peas, soybeans
Vegetables and fruit
Meat and milk
Seafood and fish
Terrestrial Systems
Plant and animal production
Use of space, water, soils, chemical
Serious impacts
Food Systems
Croplands—produce grain: about 77% of world’s food
 Rangeland—produce mostly meat from grazing livestock: about 16 %
 Ocean fisheries—produce fish and shellfish: about 7%
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Food Production
80% of world’s food supply produced by industrialized agriculture
Aka high-input: large amounts of fossil fuel energy, H2O, synthetic fertilizer,
pesticide
Industrialized agriculture
Single crops or monoculture
Found on ¼ of all cropland
Developed countries primarily
Animal Production
Livestock animals for sale
Feedlots—densely populated: 4 month holdtime
Hogs & chickens: densely populated pens/cages
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Plantation Agriculture
Type of industrialized agriculture
Tropical developing countries
Cash crops
Large monoculture plantations
Sold to developed countries
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Traditional Agriculture
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42% of people practice
1/5 of world’s food
Subsistence—produce enough food for family’s use
Human labor and draft animals
Nomadic herding
Shifting forest cultivation
Traditional Agriculture
 Traditional intensive: more human and animal power, fertilizer use, water
 Enough surplus to sell
 Increase in food production
 3 steps:
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Green Revolutions
Develop and plant monocultures
Produce high yields by using large inputs of fertilizer, water and pesticides
Increase number of crops grown per year (multiple cropping)
Green Revolutions
First: high input farming, developed countries, 1950-1970
Second: fast-growing high yield dwarfs of wheat and rice, widespread, 1967
Third: GMOs?
Requirements: fertile soil, ample water, fossil fuels to run machinery, apply
farm chemicals, run pumps
8% of world’s energy input
Soil
Complex system capable of supporting plants
Consists of;
 Disintegrated rock
 Organic matter
 Air
 Water
 Nutrients
 microorganisms
Soils
Thin covering
Develop over long time
Several layers—horizons
Cross section of horizons—soil profile
Surface Layer
O horizon—surface litter layer, freshly fallen leaves, plant and animal waste,
fungi, other organic materials, brown or black
Topsoil
 A horizon— porous mixture of partially decomposed organic matter (humus)
 inorganic minerals, darker and looser than deeper layers
O and A layers
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Plant roots anchored
Water storage
Bacteria, fungi, earthworms, small insects
Complex food webs
Decomposers rule
Color—
 dark brown to black—fertile
 Yellow, orange, red—low organic, low nitrogen
E Layer
Eluviation--loss
Zone of leaching: zone of dissolved or suspended materials
B and C Horizons
B—subsoil
C—parent material
Most of soil’s inorganic material
C lies on bedrock
Infiltration—downward movement of water through soil
Leaching—dissolved minerals and organic matter
C Layer
Derived from bedrock
Weathering—physical, chemical and biological breakdown of bedrock
 Physical: wind, rain
 Chemical interaction of H20, atmospheric gases—CO2, S
 Biological: lichens
U.S. soils—parent material from glacial deposition, wind, water
Texture and Porosity
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Size of particles—texture
Amount of space between particles—porosity
Clay, silt, sand, gravel
Permeability—rate at which water and air move from upper to lower layers
Soil Types
Soil Conservation Service—classifies soils based on structure and composition,
now Natural Resources Conservation Service
Soil texture grid
U.S.—soil orders—includes location and formation
Impacts
Soil
Water
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Fertilizer
Energy
Local
Soil Degradation
Arable land—climate, water, rich organic fertile soil
Degradation—natural & human activities decrease ability of soil to support
wildlife, livestock or crops
Erosion—loss of litter and topsoil
Erosion
Wind
Water
 Sheet—thin layer
 Rill—small channels
 Gully—large ravines that impede normal tillage
Erosion
Plant cover removed by tree cutting, grazing or farming methods
Drought
2 top layers lost
Problems if layers are lost faster than they’re replaced
Erosion
 Farming practice
 Crop type: row crops expose soil
 Plowing
 Machine use
 Loss of wind breaks
 Monoculture
 China, U.S., Canada
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Water Degradation
Imported water—Central Valley, CA
Subsidized costs
Overused
Unsuitable crops
Waterlogging—soil air spaces filled with water, no O2, roots die
Salinization: mineral salts accumulate
Energy Use
Industrialized agriculture in U. S.
 4%: crops
 2%: livestock
 6%: food
 5%: food distribution and preparation
 17%: total U.S. commercial energy use
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Desertification
Productive potential of arid or semi-arid lands falls by 10% or more
Natural climate change
Human activities reduce or degrade topsoil
GMOs
Genetically modified organisms
Add genetic information into crop plant or livestock
Soybeans, cotton, corn, tomatoes
EU bans
Ethics—corporations own the plants, make the pesticides and the fertilizer
GMOs
Less choice, corporations control everything
Unintended consequences—Southern corn leaf blight
Alter ecosystems—effects on other organisms, more invasive plants, more
aggressive animals, etc
Sustainable Agriculture
Soil conservation—decrease erosion
 Contour plowing
 Strip farming—alternate crops in different rows, can be $$$$
 Terracing
 Perennial species
 Cover crops
Sustainable Agriculture
Mulch—natural or plastic sheeting
Reduced tillage—plowing techniques, minimal soil disruption
Green fertilizer—alternate with legumes, nitrogen-fixing nodules
Low-input Sustainable
Family farms
Pt. Reyes
Sacramento delta
Labor intensive
Risky
Questions?