Soil & Soil Erosion Review Dr. East 12/09/2015

Soil Profile Review Where’s the humus? – Which has a wider A horizon, Tropical Soil or Temperate Soil? – What causes the difference in horizon width and topsoil fertility between these two places? Where is the zone of most leached material? Which layer has the oldest eroded material and rock particles?

Human Induced Soil Degradation

Degradation for Different Reasons

Soil Degradation in US

Erosion VS Deposition erosion = process by which the materials of the Earth’s surface (plants, rock or soil) are: 1) loosened, dissolved, or worn away (aka weathering that forms sediments) and 2) then moved (transported) elsewhere – Major Forces of erosion = WATER (#1), WIND, GLACIERS/ICE – Plant roots, animal actions, etc also help in mechanical weathering too Deposition = the process of the laying down or depositing of sediments as transporting forces die down (water slows or stops, wind slows or stops, glaciers “retreat” or melt, etc.)

Soil Erosion Is a natural process that occurs mainly thorough the action of the water cycle … stuff gets washed away naturally However, problem exists when the process is too rapid and exceeds soil formation processes Occurs because of poor farming practices – Allowing animals to overgraze and permanently remove stabilizing plant roots – Improper plowing techniques that cause gullies – Too much irrigation on steep slopes Related: Soil depletion and land degradation occurs because of overgrowth of one particular crop and thus loss of nutrients or loss of topsoil

Soil Erosion Cont. Occurs because of urban sprawl and poor construction practices that don’t try to prevent surface runoff after land is cleared Occurs because poor mining practices that scrap away topsoil without reclamation Occurs because of global warming that increases sea level and causes beach erosion because of higher tides Where: Occurs on the margins of deserts (like Sahel in Africa, steep mountainous regions, and any place that doesn’t practice soil conservation methods)

What are some methods places around the world are using to try to prevent soil loss and degradation/nutrient depletion?