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History of Agriculture. The Early Years. 10,000 years ago people began to: domesticate and raise animals cultivate the soil selectively breed certain wild plant species crops Traditional Agriculture – produce enough to eat Polyculture- Mixed crops
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The Early Years • 10,000 years ago people began to: • domesticate and raise animals • cultivate the soil • selectively breed certain wild plant species crops Traditional Agriculture – produce enough to eat Polyculture- Mixed crops ---------------------------------------------------------------Think: subsistence farming- meaning they became more self-sufficient
Effects • Abundance of food exponential population growth • Deliberate cultivation of food environmental degradation ----------------------------------------------------------- Positive Feedback Loop: more food = more people, leads to more food production
Industrial Revolution Industrial Agriculture/Agribusiness • Farming became more mechanized and standardized • fossil fuel use increased • Increased food output/Boost in crop yields • Better transport, Harvesting • Increase in irrigation • Use of synthetic fertilizers • Use of chemical pesticides • Monoculture- single crop grown in one area
Energy Subsidies • Energy input per calorie of food produced • For example, we use 5 calories to produce food and we receive 1 calorie of energy when eat that food = then the food has energy subsidy of 5 • This was the point of doing the Land Use Lab
Green Revolution • Began in 1950s because of increase in population • Involved: new management techniques, mechanization, fertilization, irrigation, monocropping and improved crop varieties • World grain production doubled ---------------------------------------------------------- Example: Agricultural scientists developed new strains of wheat that produced higher yields and were disease resistant
Farming Process • Step 1 (Fieldwork) involves: plowing, planting, irrigating, weeding, protection from pests, harvesting, and preparing for the next season • Step 2 (Harvesting) involves: drying, sorting, cleaning and preparing crops for market • If fossil fuels are cheap and available it is more economically advantageous to use machines over people ----------------------------------------------------------- Developed countries (wages are relatively high)– 5% of workforce works in agriculture Developing countries (wages tend to be much lower) – 40-75% of workforce works in agriculture
Mechanization • Large farms tend to be more profitable that small farms because average cost of production falls as output increases • Large up-front expenditure is a good investment for a large farm due to profit • Single crop farms are more efficient than farms that grow many crops • Specialized equipment for each crop
Irrigation- Benefits • Has ability to transform unsuitable land into suitable land for growing crops (Ex. Former desrt in SE Cali. is now major producer of fruit and vegetables) • Allows “productive land” to become “extremely productive”
Irrigation- Negative Consequences • Deplete groundwater and draw down aquifers • Promote saltwater intrusion into freshwater wells • Contribute to soil degradation • Waterlogging (soil remains underwater for long periods of time – impairs root growth) • Salinization (small amounts of salt in irrigation water become highly concentrated)
Fertilizers • Agriculture removes organic matter nutrients from soil (soil in constant production) large amounts of fertilizer are used to replace nutrients • Fertilizers contain essential plant nutrients: nitrogen, phosphorus, potassium ----------------------------------------------------------- Organic – animal manure that has been allowed to decompose Synthetic – produced commercially, highly concentrated (review effects from last unit)
Monocropping • Large plantings of single species or variety • Dominant agriculture practice in US (wheat and cotton) • Improved agriculture productivity- allows for ease of planting and harvesting or uniform fertilizer and pesticide treatment ----------------------------------------------------------- • Leads to environmental degradation- • soil erosion caused by wind and exposure • reduction in productivity because of loss of topsoil nutrients • makes crops more vulnerable to attack by pests
Pesticides • Has become routine and widespread because of increased pest problems due to monocropping • 227 million kilograms of pesticides are applied to food, crops, cotton and fruit trees in US • US has one-third of the worldwide pesticide use ----------------------------------------------------------- • A substance (natural or synthetic) that kill or control organisms people consider pests
Types • Insecticides- target species of insects and other inverts • Herbicides- target plant species that compete with crops
Application • Pesticides can be: • “broad spectrum” meaning they kill many different pests • “selective” meaning they focus on a narrow range of organisms ----------------------------------------------------------- • Application can be easy and is relatively rapid • Single application can reduce a pest popultaion • Made agriculture more efficient • Allows for greater crop yields
Environmental Concerns • Pesticides injure or kill organisms other than intended targets • Some are persistent, remaining in environment for long time • DDT- banned in 1972 in US • DDT builds up in fatty tissues of organisms over time, bioaccumulation • DDT Can be transfer to other organisms that eat infected organisms • Some are nonpersistent, meaning they breakdown rapidly in weeks to months • Ex. Round Up • Fewer long term effects • Must be applied often • Overall impact is still concern • Pest populations become resistant to pesticides over time, which then leads farmers and scientists to search for new pesticide • Can kill organisms that benefit farmers, pollinator insects, and plants that fix nitrogen to improve soil fertility
Traditional Breeding • Enhance desired traits • Ex. Herbicide resistant, improvement of nutritional content • See video clip for details
Genetic Engineering • Isolate genes and insert them into other organitms • Ex. Bt crops (corn, soybeans, wheat) • See video clip for details • Bt video clip • Salmon video clip
Advantages of GM crops • Pest resistance • Herbicide tolerance • Disease resistant • Cold tolerant • Drought tolerant • Salinity tolerant • Nutritional • Phytoremediation
Incentives to produce GMOs • The process of genetic engineering takes 6 times as much time as traditional methods • It cuts cost • It allows for all kinds of potential product development • More than two thirds of food products in US contain ingredients made from GM crops
Basics • Grain crops of plant monocultures are bred or enhanced to produce high yields • High yields are sustained using large amounts of water, fertilizers, and pesticides • Number of crops grown each year is increased by multiple cropping (growing two or more crops in the same space during a single growing season )
Green Revolutions • 1st (1950-1970) • 2nd (1967- present) in devloping countries with enough rain and/or irrigation capabilities
Unsustainable • Increasing food production is not the same as increasing food security • Produces monocultures, while traditional agricultural produces polycultures • Drop in productivity of land that has been over farmed (30+ years) • Caused small farms to go into debt • Increases use of pesticides • Increased irrigation leads to salinization, waterlogging, decreased water levels • Reduced agricultural biodiversity • Food more susceptible to pathogens • Permanent loss of specific genetic traits
