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Chapter 1 The Importance of Soil

Chapter 1 The Importance of Soil. How Soils Have Shaped Human History. Why do you find so many Indian artifacts (arrowheads and pottery) near creeks, streams and rivers? Where are the most productive soils found?. The Nile Delta The Yellow River Mississippi River Floodplains.

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Chapter 1 The Importance of Soil

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  1. Chapter 1 The Importance of Soil

  2. How Soils Have Shaped Human History • Why do you find so many Indian artifacts (arrowheads and pottery) near creeks, streams and rivers? • Where are the most productive soils found? • The Nile Delta • The Yellow River • Mississippi River Floodplains Upper Mississippi River Watershed People settle where the good soils are!

  3. Terraced Agriculture Production in China along Yellow River Around 300 million people are supported by the Ganges Delta, and approximately 400 million people live in the Ganges River Basin…good soils support agriculture, which feed the masses

  4. The Fertile Crescent (used to be super-fertile!) • Flooding of Tigris and Euphrates fertilized soil • Irrigation, drainage produced abundant crop yields • Competition and warfare between city states (including Babylon) • Over-salinization reduced wheat productivity in south by 2,000 • B.C. - political power shifted north • Eventual large scale ecological • destruction • Forests cleared for fuel, ship • building • Fields and pastures worked until • barren • Exploitation of soil resources led to collapse of civilization!! This area is STILL fighting over resources

  5. Global Soil Issues: The following slides highlight major regional soil issues/problems

  6. Land in the Amazon is being cleared for tropical timber and converted for soy production and cattle A lot of cotton (which is an intensive crop) is cultivated in central and eastern Europe.

  7. American Dust Bowl • 1930s--Resulted from poor soil management, drought, • wind erosion • Over 150,000 square miles affected

  8. Only about 11% of land has soil capable for agricultural production.

  9. Soils are made up of more than just “DIRT”.

  10. The soil plays a very important role in the Carbon Cycle as a storage area for carbon, gases, water, and nutrients. Carbon produced by photosynthesis is eventually released back into the soil and atmosphere. This has a major impact on the global climate.

  11. Soil is our life-support layer: Continental crust is about 50 miles thick Lower atmosphere is about 25 miles deep Soil layer is very thin (only a few feet) Atmosphere, crust, and soil all interact to sustain life on earth—providing sufficient temperature, oxygen (gases), water, carbon, and nutrients

  12. Nutrient sink Nitrogen enters the soil through the atmosphere via soil organisms that convert nitrogen into a usable form for plants. Nitrogen is carried to other layers, consumed in plants, returned to the atmosphere as a gas, etc. 14 other nutrients needed by plants come from soil. C, H, O come from air and water…the rest stored in soil.

  13. Water Holding Soils hold water/moisture that is absorbed by plants. “For each pound of dry matter produced by growth, plants use between 200 and 1,000lbs of water for photosynthesis, sap flow, nutrient use, etc.”

  14. Temperature Regulator Most plant roots in temperate areas grow in soil temperatures above 40-50°F

  15. Soil providesanchorageand acts as a reservoirfor water, oxygen, and nutrients

  16. Air and Aeration Plant roots and soil critters use O2 and give off CO2 as they respire Waterlogged soil has less oxygen than “well-aerated soils”

  17. But…soils provide us more than just stuff to grow our food on….. Housing Materials to make sod and adobe homes

  18. Waste disposal Landfills Biosludge solids spread through plantation forest

  19. Recreation Golf courses, parks, athletic fields

  20. Engineering Underground utilities, dams, roads and building foundations

  21. Soil Degradation Erosion

  22. Desertification

  23. Salinization Accumulation of excess salts • Results in part from: • applying excessive amounts of synthetic fertilizers • improper irrigation practices

  24. Disappearance According to some data, about 0.5% of agricultural soil is lost every year through construction of different infrastructural objects and urbanization (soil sealing).

  25. Soil Pollution

  26. Soil pollution typically arises from: • Rupture of underground storage • tanks • Application of pesticides and • herbicides, percolation of • contaminated surface water to • subsurface strata • Leaching of wastes from landfills • Direct discharge of industrial • wastes to the soil • The most common chemicals involved are petroleum hydrocarbons, solvents, pesticides, herbicides, lead and other heavy metals

  27. Mining

  28. Specific problems here in WNC

  29. Creek debris Peeks Creek - Macon Co, NC

  30. What to do???? Best Management Practices Specific practices to preserve soil and water resources while being practical and profitable Conservation tillage Buffer zones Silt Fences

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