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Class15 - Chemistry 83 Food Technologies What is the...

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Chemistry 83 Class15 1 Food Technologies Cunningham/Saigo, Environmental Science, 6th, McGraw Hill, MA, 2001, 130 Starvation, disease, pestilence, and war were predict- ed by Malthus (population) (food) Thomas Malthus, British economist, observed in 1798 food production increased linearly while population increased geo- metrically. He predicted dire consequences when population exceeds food. Consequences have so far been delayed by technol- ogies, but how much longer? What is the Malthusian hypothesis?
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Chemistry 83 Class15 2 What problems must be overcome to supply food to a growing population? Loss of arable land - as population increases, arable land decreases Water - 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, etc. Competition from pests (weeds, insects, worms, etc.) amounts to 30% food loss Decomposition of stored food - limited storage time due to spoilage of food How do current technologies deal with these food problems? • Improved productivity to makeup for loss of arable land New crop varieties - high-yield, disease-resistant wheat varieties were produced by cross-polination (Norman Borlaug, father of Green Revolution, Nobel Peace Prize in 1970) Mechanization of farming Irrigation to augment the water cycle 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 Class15 3 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 source of water soluble N, P, and other minerals needed to produce food. What is the role of soil in producing foods? Figure 2. Composition of soil Figure 1. Soil provides water soluble N and P Figure 3. “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
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Class15 - Chemistry 83 Food Technologies What is the...

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