Graphic, above: Soil is a much more complex living thing than most people realize. All the mineral soil on earth today ultimately came from rocks created by ancient geologic forces. As this mineral soil is mixed with organic matter, bacteria, fungi and other soil organisms, it develops into a vibrant and very dynamic ecosystem with thousands (some say billions!) of different organisms.

The process of soil formation, or soil genesis, starts with the weathering of rock.  Weathering includes both the physical and chemical breakdown of rock by wind and water which results in smaller and smaller pieces which we know as sand, silt and clay. Soil begins to form when these small pieces of weathered rock are colonized by soil bacteria and fungi which further weather the soil particles. The process of soil genesis happens the fastest at the surface where wind, rain and changes in temperature help the process along, and as water moves down through the developing soil, it carries with it a wide range of dissolved molecules that lead to the development of deeper soils. Over years, soils form layers (called horizons) from top to bottom that each have different characteristics and functions in the ecosystem. When earthworms invade a forest, they rapidly change the soil layers found in the forest and that has big implications for forest plants and animals.

Starting at the top, let’s see what happens to the typical soil layers of a hardwood forests when earthworms invade. [more] See Hour 1, 1491: New Revelations of the Americas Before Columbus by Charles C. Mann

JOHN BATCHELOR SHOW

Hour One

Sunday 29 December  2013 / Hour 1, Block A: 1491: New Revelations of the Americas Before Columbus by Charles C. Mann (1 of 4)

Sunday 29 December  2013 / Hour 1, Block B: 1491: New Revelations of the Americas Before Columbus by Charles C. Mann (2 of 4)

Sunday 29 December  2013 / Hour 1, Block C: 1491: New Revelations of the Americas Before Columbus by Charles C. Mann (3 of 4)

Sunday 29 December  2013 / Hour 1, Block D: 1491: New Revelations of the Americas Before Columbus by Charles C. Mann (4 of 4)

Hour Two

Sunday 29 December  2013 / Hour 2, Block A: Turning Dust to Gold: Building a Future on the Moon and Mars  (Springer Praxis Books / Space Exploration) by Haym Benaroya (1 of 2)

Sunday 29 December  2013 / Hour 2, Block B: Turning Dust to Gold: Building a Future on the Moon and Mars (Springer Praxis Books / Space Exploration) by Haym Benaroya (2 of 2)

Sunday 29 December  2013 / Hour 2, Block C: The Lost Photographs of Captain Scott: Unseen Images from the Legendary Antarctic Expedition by David M. Wilson (1 of 2)

Sunday 29 December  2013 / Hour 2, Block D: The Lost Photographs of Captain Scott: Unseen Images from the Legendary Antarctic Expedition by David M. Wilson (2 of 2)

Hour Three

Sunday 29 December  2013 / Hour 3, Block A: The Last Viking: The Life of Roald Amundsen (A Merloyd Lawrence Book) by Stephen R. Bown (1 of 4)

Sunday 29 December  2013 / Hour 3, Block B: The Last Viking: The Life of Roald Amundsen (A Merloyd Lawrence Book) by Stephen R. Bown (2 of 4)

Sunday 29 December  2013 / Hour 3, Block C: The Last Viking: The Life of Roald Amundsen (A Merloyd Lawrence Book) by Stephen R. Bown (3 of 4)

Sunday 29 December  2013 / Hour 3, Block D: The Last Viking: The Life of Roald Amundsen (A Merloyd Lawrence Book) by Stephen R. Bown (4 of 4)

Hour Four

Sunday 29 December  2013 / Hour 1, Block A: Arctic Mission: 90 North by Airship and Submarine by William F. Althoff  (1 of 2)

Sunday 29 December  2013 / Hour 1, Block B: Arctic Mission: 90 North by Airship and Submarine by William F. Althoff  (2 of 2)

Sunday 29 December  2013 / Hour 1, Block C: The Roof at the Bottom of the World: Discovering the Transantarctic Mountains byEdmund Stump (1 of 2)

Sunday 29 December  2013 / Hour 1, Block D: The Roof at the Bottom of the World: Discovering the Transantarctic Mountains byEdmund Stump (2 of 2)

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Music

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