21a_desertificationSP2008

21a_desertificationSP2008 - Geography 1000 Spring 2008...

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1 Geography 1000 Spring 2008 Lecture 21: Dry land Degradation and why is it important? Some few terms for our dry topic and even drier test • Desertification pp. 205-207, 210, 215-215 • Hindu Kush case study p. 214 • Erosion p. 210 Lecture Goals • Introduce land degradation and its causes. • Discuss the “geography” of the global problem of desertification. • Focus on desertification and efforts to reverse desertification. • Define no-till agricultural practices and minimum tillage.
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2 Earth surface Water 71% of Earth surface 36.1 billion ha Ice, Rock Desert Semi- desert Undegraded Vegetated Land 9.6 billion ha Degraded Vegetated Land 1.9 billion ha 17% of total vegetated land 3.4 bil ha unvegetated 29% Land Areas of Concern for Soil Degradation Types of Soil Degradation
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3 The BIG Two!! • Wind and Water erosion are responsible for MOST land degradation in terms of area. These forces, however, are exacerbated greatly by human activities. Chemical and Physical Degradation • Chemical degradation: loss of nutrients acidification salinization pollutants (pesticides, metals, etc) • Physical degradation: compaction waterlogging Major Causes of Soil Degradation
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21a_desertificationSP2008 - Geography 1000 Spring 2008...

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