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Nature = FoodPart 1: Agriculture
• Nature is the ultimate source of all food consumed by humans
• Some of this food is recognizable (unprocessed vegetables and meats), while some is not (Twinkies are a good example!)
• Some of the food is wild caught/harvested, while the rest is produced (cultured) for us via agriculture and aquaculture
Modern Food Supply
• World food supplies have more than kept up with human population growth over the past two centuries.– 1950 - 2.5 billion people - average daily diet was less
than 2,000 calories/person.– 2001- 6.0 billion people - world food supply can
provide more than 2,500 calories/person.– 2007 Currently, more than 4,000 calories of food are
made per day for each American• Of course, food is more than calories and there is
mounting evidence that the Western diet is full of empty calories and lacks important nutritional components (‘Unhappy meals’)
Modern Food Supply• The most common dietary problem in wealthy countries
is over-nutrition.– In North America and Europe, average daily per
capita caloric intake is 3,500 calories.– Leading to serious medical problems associated with
obesity (for example, heart disease, diabetes, high blood pressure)
• Sub-Saharan Africa has not kept food production up to pace of population growth– As a consequence they depend on foreign nations and aid
organizations to provide food assistance
• Collapse of Soviet Union and Eastern Europe led to significant collapse in food production.
• An overweight world diagram
Modern Food Supply• Food security - the ability to obtain sufficient food on a
daily basis• About 1 in 5 people in the developing world are
considered chronically hungry.– 200 million children
• Can lead to permanently stunted growth, mental retardation, and other developmental disorders.
– Poverty is the greatest threat to food security
Food as nutrients• Macronutrients – nutrients that are required in large
quantities– Carbohydrates, lipids, and proteins– Water
• Micronutrients – nutrients that are required in small quantities (and larger quantities can be toxic)– Vitamins and minerals
• Essential nutrients – nutrients that cannot be made in an organism (biochemically) and are therefore necessary components of the organisms diet– Omega fatty acids
• The foods we eat are essentially combinations of nutrients, essential nutrients, and energy
Food as nutrients• Malnourishment - nutritional imbalance caused by a
lack of specific dietary components• Protein Deficiency Disorders
– Kwashiorkor - “Displaced Child” - Occurs mainly in children whose diet lacks high-quality protein.• Reddish-orange hair, bloated stomach
– Marasmus - “To Waste Away” - Caused by a diet low in both protein and calories.• Very thin, shriveled
Food as nutrients• Iron deficiency
– The most common dietary imbalance in the world.– Leads to anemia.
• Increases risk of death from hemorrhage in childbirth and affects development.
– Sources of iron: red meat, eggs, legumes, and green vegetables
Agriculture• Biologists estimate that there are roughly 30,000 plant
species with parts that humans can eat• Majority of our food supply (90%) is derived from only 15
plant and 8 animal species• Three grains, wheat, rice, and corn, provide almost half
of the calories consumed by people– These three species are all annual plants
• 2 out of 3 people on Earth survive primarily on grains• Two major types of agricultural systems:
– Industrialized– Traditional (practiced by roughly half of the world’s
population)
Industrialized Agriculture
• Also referred to as high-input agriculture• Requires large amounts of energy, water, fertilizers,
antibiotics, and pesticides; three of which come from fossil fuels
• Produce huge output of single crops (monocultures) or livestock (which are often fed monoculture products)
• Accounts for roughly 25% of the world’s cropland• Mostly in developed countries, but it is spreading into
developing nations
Plantation Agriculture
• Form of industrialized agriculture practiced primarily in tropical developing countries
• Cash crops, such as bananas, coffee, and cacao (chocolate and cocoa butter)
• Grown for sale in developed countries
Traditional Agriculture
• Traditional Subsistence Agriculture – Only enough crops and livestock are produce to support
a farm family– In good years surpluses might be sold for cash, trade,
and store– Variety of different forms of subsistence agriculture:
• Shifting cultivation and nomadic livestock herding are example
• Traditional Intensive Agriculture– Increased inputs of labor (human and animal), fertilizer,
and water – Increased outputs of crops and livestock, which are
available for sale
Green Revolutions• Green Revolution – systematic application of new technology
to improve crop yields
– Three steps involved:
• Developing and planting monocultures of selectively bred or genetically-engineered high-yield varieties of crops; emphasis placed on plant growth instead of seed growth and development
• Use of large quantities of fertilizer, pesticides, antibiotics, and water to increase yield
• Increase frequency and intensity of cropping (more crops per year and increased acreage)
– Two recognized green revolutions:
• 1950-1970 developed world
• 1970 – current developing world
Why Livestock?• One of the principal uses of animals in agriculture is to
transform plant material into high-quality protein (Protein conversions)
• In traditional agriculture, livestock graze land, taking nutrients in and then they defecate and return some of the nutrients to the same field
• In industrial agriculture, livestock are fed grains (corn particularly, which they are not “designed” to do) and not necessarily in a field, so the manure does not fertilize a field
• Per capita meat consumption has increased 29% between 1950 and 1996
• 1/5th of the world’s population consume roughly half of the world’s grain production through livestock
Organic Revolution• Began in the mid-1900s in response to growth of industrial
agriculture• Focus placed back on soil fertility and sustainability
– No inorganic fertilizers or pesticides used– Organic fertilizers (i.e., manure, compost, peat, etc) and
“natural” pesticides are used (i.e., soaps, plant derived pesticides, etc.)
– No antibiotics added to animal feed– Reduced amounts of fossil fuels; smaller in scale so less
demand/need for fossil fuels– Animals and plants lead a more natural life
• Boom in “organic” foods has led to modern industrial organic revolution– Reversing some of the trends of the initial organic revolution– Better than contemporary, non-organic industrial agriculture,
but there are naysayers.
Benefits of Traditional Methods• In stark contrast to monocultures, many traditional agricultural
methods involve interplanting– Interplanting – simultaneously growing several crops on the
same plot• Types of interplanting
– Polyvarietal cultivation – several varieties of the same crop– Intercropping – two or more different crops are grown in the
same plot (grain plus legume)– Agroforestry – mixed crop and shrub/forest farms;
shrubs/trees provide nitrogen or firewood– Polyculture – most complex form of interplanting with many
different types of plants and animals growing together• Studies have shown this method to produces/maintains
the soil ecosystem and produces higher yields (higher than monocultures)
The problems with/caused by modern agriculture
• Agriculture, particularly the industrialized forms, has a profound and significant negative impact on air, soil, water, and biodiversity resources
• Humans and human health is also negatively impacted• Negative aspects of cost the US $150-200 billion per year
(Pimentel estimate), a cost which is not reflected in the actual cost of food
• What are the specific negative impacts and their costs?
The problems with/caused by modern agriculture
• Biodiversity loss– Loss of habitat through conversion of grasslands and
forests along with wetland draining– Fish kills from agricultural runoff– Extermination of predators– Loss of genetic diversity due to monocultures– Genetic pollution from bioengineered or selectively bred
organisms that “escape” and interbreed with native species
– Spread of diseases from agroecosystems to natural ecosystems
The problems with/caused by modern agriculture
• Soil– Loss of soil fertility– Salinization of soil– Waterlogging– Desertification– Soil loss through erosion
The problems with/caused by modern agriculture
• Air– Greenhouse gas emissions from fossil fuel use– Other air pollutants from fossil fuel use– Air pollution from pesticide sprays– Toxic odors from livestock waste (manures and their
associated smells)
The problems with/caused by modern agriculture
• Water– Aquifer depletion– Increased runoff, due to land clearing and plowing– Sediment pollution from runoff– Fish kills from pesticide runoff– Surface and groundwater pollution from pesticides,
antibiotics, and fertilizers– Over-fertilization of lakes, rivers, and coastal ocean
from fertilizers, livestock wastes, and food processing wastes
The problems with/caused by modern agriculture
• Human Health– Nitrates in drinking water– Pesticide contamination of foods, drinking water, and
air (all have significant and measurable concentrations)– Contamination of drinking water with diseases from
livestock– Bacterial contamination of meat and produce
Overweight world
Protein making machine efficiency
AnimalKilograms of grain required per
kilogram of body weight
Beef cattle 7
Pigs 4
Chicken 2.2
Fish (catfish or carp)
2
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