HR Test Two Study Guide_Summer2010 ANSWERS 1 (2)

HR Test Two Study Guide_Summer2010 ANSWERS 1 (2) - Geol...

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Geol 112/ENSP 200 HR Test Two Study Guide Summer 2010 Chapter 7 (1) What is the difference between high input vs low input agricultural practices? (2) What is the difference between industrialized vs. Traditional intensive agriculture. In particular what is the difference in the amount of energy it takes to produce food for both. (3)How can Traditional intensive agriculture be so much more sustainable? (4)Which activities can accelerate soil erosion? Soil Erosion and Degradation Topsoil loss is caused primarily by the action of either wind or water Topsoil loss is a natural process, but one that has been greatly accelerated by agricultural practices Lesson – don’t expose the topsoil unless it can be protected Some soils are also much more susceptible, particularly ones with little organic matter (5)Given all of our technological advances, why do we still have soil erosion problems in the US? (6)What are the problems caused by over- irrigation? (Salinization and waterlogging) Effects of Irrigation Leaves behind salts in topsoil Salinization Remedies expensive and complex Waterlogging Attempts to leach salts deeper but raises water table Growing worse Salinization and Waterlogging Irrigation is a marvel – turning deserts into farms, but there is a price 1/5 of world cropland is irrigated – producing 40% of world’s food Irrigation water contains dissolved minerals – picked up through leaching Any water not absorbed by plants often evaporates, leaving behind salt (leached minerals) (7)What did the Green revolutions require farmers to do? Does it have limitations?
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Green Revolution Classic high input agriculture Relies on monoculture Produce more crops per acre using hybrids and genetically engineered plants Higher yields involve the use of more water and requires good soil, as well as high inputs of fossil fuel and pesticides Grow more crops per year (multiple cropping) Original GR started in the 1950s Second one started in 1967 using faster growing species of rice and wheat Supposedly this is a way to protect biodiversity – less land disruption Either way, this intensive farming method uses about 8% of the worlds oil output Limits to Expanding Green Revolutions High-inputs too expensive for subsistence farmers Multicropping has limits Water not available for increasing population Irrigated land per capita dropping Significant expansion of cropland unlikely for economic and ecological reasons (8)What are the environmental impacts of agriculture? Agriculture’s Environmental Impact
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This note was uploaded on 01/26/2011 for the course GEOL 112 taught by Professor Dean,w during the Summer '08 term at Clemson.

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HR Test Two Study Guide_Summer2010 ANSWERS 1 (2) - Geol...

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