Third hour examID: eee105 Password: prAIRie Friday April 12 noon here 100 points (of 500 for semester) 29 questions 57 bubbles If University-approved conflict Sign up with Karin Nelson by Wednesdays lecture SoilSoil Ch. 14 EEE 105Name: eee105 Password: prAIRie Erosion - Wearing away and transportation of soil by wind and water. SoilSoil Worldwide removes 25.4 Billion tons/yr Made worse by deforestation Poor agricultural practices increase erosion and lead to the transport of associated fertilizers and pesticides and desertification DesertificationDesertification DesertificationDesertification DesertificationDesertification DesertificationDesertification DesertificationDesertification Climate change Deforestation Overgrazing Poor farming practices DesertificationDesertification The U.S.Inter-Mountain West DesertificationDesertification SalinizationSalinization Calcium Sodium H2OH2OH2OH2O SalinizationSalinization Erosion SoilSoil Most current agricultural areas lose topsoil faster than it can be replenished Wind erosion Water erosion Erosion - Wearing away and transportation of soil by wind and water. SoilSoil Erosion SoilSoil SoilSoil Sustainable farming Illinois Erosion & Sediment Control Law called T by 2000 T = tolerable soil loss 3-5 tons/acre/year Erosion SoilSoil Conservation tillage Sustainable farming Erosion SoilSoil Conservation tillage Sustainable farming Hedgerows Erosion SoilSoil Conservation tillage Sustainable farming Hedgerows Perimeter wetlands Erosion SoilSoil Great Plains have had four serious bouts of wind erosion since late 1800s. Agriculture and Pest Management Chapter 15 Thomas Malthus time food population Doomsday Essay on Population 1798 Ancient Agriculture Plant Breeding Green Revolution Norman Borlaug International Maize and Wheat Improvement Center, El Batan, Mexico Nobel Peace Prize 1970 Agricultural Methods Slash and Burn Particularly useful on thin tropical soils Vegetation is cleared for agriculture and burned to release nutrients Agricultural Methods Slash and Burn Particularly useful on thin tropical soils But depletes soil nutrients Cleared soil useful for only 3-5 years Vegetation is cleared for agriculture and burned to release nutrients Mechanized Agriculture Typical of industrialized countries Requires large amounts of energy and flat land. Often monocultures Requires large amounts of energy and flat land. Typical of industrialized countries Mechanized Agriculture Monocultures vulnerable to pest invasion to evolution of new pests Monocultures elm trees lined the Quad in the 1940s all died of the Dutch Elm Disease Often monocultures Requires large amounts of energy and flat land. Typical of industrialized countries Mechanized Agriculture Hybrid crop varieties High technology Mechanized Agriculture Problems With Mechanized Agriculture soil erosion fertilizer runoff depletion of soil nutrients lead to increased fertilizer use irrigation depletes aquifer ground water monoculture often leads to increased pesticide use PESTICIDES Pesticide - Any chemical used to kill or control populations of unwanted fungi, plants, or animals. Insecticides Used to control insect populations yr. Ago Homer noted the use of Sulfur to control insects. Known for centuries that certain plant products produce repellant chemicals. Nicotine (tobacco) Coevolution of chemical defenses Coevolution Monarch, milkweed mimicry, mimicry Herbicides Used to control unwanted plants. About 60% of pesticides used in US are herbicides. Weeds compete with crops for soil nutrients. Traditional weed control methods are expensive in terms of time and energy. Herbicides Used to control unwanted plants. About 60% of pesticides used in US are herbicides. Weeds compete with crops for soil nutrients. Traditional weed control methods are expensive in terms of time and energy. Herbicides transgenic herbicide resistant crops Fungicides and Rodenticides Fungicides are an important defense against spoilage of both seeds and mature crops. In some parts of the world, governments place a reward on rats because they can destroy agricultural crops. But pests evolve DDT resistance Herbicide resistant weeds escaped genes Warfarin-resistant rats corn root borer But pests evolve Corn root borer starved on soy beans Alternate corn & soy beans annually But in late 80s a new strain of borer evolved which could feed on soy beans corn root borer But pests evolveevolve corn rootborer But pests evolve