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Environmental Science
Environmental Science 1021F/G
Geoff Stewart

CHAPTER 18: AGRICULTURE -AZOLLA is an insidious fernlike plant that grows on the surface of water -chemical fertilizers relies on cheap energy and lots of water – it also impaired ecosystem services – these fertilizers are also expensive -ORGANIC AGRICULTURE: farming that does not use synthetic fertilizer, pesticides, and other chemical additives like hormones (for animal rearing) -GREEN REVOLUTION: plant-breeding program in the mid-1900s that dramatically increased crop yields and led the way for mechanized, large-scale agriculture -high yield varieties are those plants that have been selectively bred to produce more than the natural varieties of the same species, usually because they grow faster or larger or are more resistant to crop diseases (maize, wheat, rice) -the combination of high yield varieties and existing technology resulted in a 1000% increase in global food production and a 20% reduction in famine between 1960-1990 -excess fertilizers that run off into waterways causes algae, aquatic plants, and cyanobacteria to grow into massive blooms – these blooms block sunlight which shuts down underwater photosynthesis -EUTROPHICATION: nutrient enrichment of an aquatic ecosystem that stimulates excess plant growth and disrupts normal energy uptake and matter cycles -pest populations develop resistance to pesticides – thus making us use more and more pesticides making more and more pest résistance -in 2010, 925 million people were underfed or malnourished -poor nutrition is the cause of disease -5 million child deaths to poor nutrition per year -FOOD MILES: the distances a food travels from its site of production to the consumer – the greater the food miles the greater the ecological footprint of that food -global population is suppose to reach 10 billion by 2050 THE NATURAL WORLD HOLDS ANWERS TO SOME ENVIRONMENTAL PROBLEMS -ducklings ate bugs and weeds – azolla in rice beds -loaches is a type of fish that eats azolla as well and can be harvested and sold as fish meat -azolla contains symbiotic bacteria that produces a usable form of nitrogen - between the nitrogen from the azolla, and the poop from the ducklings and fish, no fertilizer was needed SOME INDUSTRIAL AGRICULTIRAL PRACTICES HAVE SIGNIFICAN DRAWBACKS -two Green Revolution’s legacies are: MONOCULTURE CROP PRODUCTION & CONCENTRATED ANIMAL FEEDING OPERATIONS FOR LIVESTOCK -MONOCULTURE: farming method in which one variety of one crop if plants, typically in rows over huge swaths of land, with large inputs of fertilizer, pesticides, and water – easier to maintain and harvest – easier for mass production and better bountiful harvest -CONCENTRATED ANIMAL FEEDING OPERATION: meat or dairy animals being reared in confined spaces, maximizing the number of animals that can be grown in a small area – they do not graze or roam free – this method minimizes the land used and it is easier to harvest the manure and sell it as fertilizer -disadvantages of these methods include: they contribute heavily on global warming by clearing land there is less amount of carbon that can be absorbed through photosynthesis; fertilizer and livestock contribute
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