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Lecture1610fb - Chemistry 83 10/28/10 Food Technologies...

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Chemistry 83 10/28/10 1 Food Technologies Cunningham/Saigo, Environmental Science, 6th, McGraw Hill, MA, 2001, 130 Starvation, disease, pestilence, and war predicted by Malthus (population) (food) Thomas Malthus, British economist, observed in 1798 food production increases linearly while population increases geo- metrically. He predicted dire consequences once the lines cross each other. Consequences have been delayed by technologies
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Chemistry 83 10/28/10 2 Problems that must be overcome to increase food supply • Loss of arable land - as population increases, arable land decreases • Weather - uneven availability of water – largest constituent of living matter • Loss of nutrients in soil due to slow rates of geochemical cycles that provide N, P • Competition from pests (weeds, insects, worms, etc.) amounts to 30% food loss • Decomposition - limited storage time due to spoilage of food Technologies that currently deal with the food problems • Irrigation to augment the water cycle • Improved productivity to makeup for loss of arable land – New crop varieties - high-yield, disease-resistant wheat varieties (Norman Borlaug, father of Green Revolution, Nobel Peace Prize in 1970) – Mechanization of farming • Fertilizers to replenish and augment the nutrients in the soil that are limited by the slow natural N and P cycles • Pesticides to decrease competition from insects, weeds, etc. • Refrigeration and food additives to slow decomposition of food
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Chemistry 83 10/28/10 3 Fertilizers Augmenting the slow N and P geochemical cycles http://www.physicalgeography.net/fundamentals/images/soil_breakdown.gif When rocks are exposed to air, rain, sun, freeze/thaw cycle, and plants; erosion occurs to produce mineral particles. Humus is decayed matter that serves as the natural sources of N, P, and other minerals. Soil is source of N and P for producers Figure 1. Composition of soil
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Chemistry 83 10/28/10 4 Figure 2. “Slash and Burn“ Agriculture http://www.bized.ac.uk/virtual/dc/images/photos/00039.htm Trees are cut and burned to obtain their mineral ashes. Ashes spread on soil serve to fertilize the soil. In 2-5 years, however, the soil tends to become barren and likely to be blown away. Still occurs in civiliations in tropical rain forests. Early attempts to augment N and P were not sustainable
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This note was uploaded on 12/19/2010 for the course CHEM 83 taught by Professor Bonk,j during the Fall '08 term at Duke.

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Lecture1610fb - Chemistry 83 10/28/10 Food Technologies...

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