Targeting the soil quality and soil health concepts when ...
Chapter 8: Soil. Goals Understand how the soil quality determines what can grow Understand how soil...
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Transcript of Chapter 8: Soil. Goals Understand how the soil quality determines what can grow Understand how soil...
Chapter 8:Soil
Goals• Understand how the soil quality
determines what can grow • Understand how soil quality can determine
the survival of societies
Note: Fig. 8-4 in our book also includes the “E horizon”
O Horizon• Humus- dark, soft, spongy residue of
organic matter as a result of decomposition of organic matter such as leaves and dead wood
• 1 ۫ source of nutrients in soil systems
A Horizon
• Top soil-mixture of humus and leachial mineral soil
• Thin roots extend into this layer
E Horizon• Eluviation
process of leaching (note: You may see this word spelled with and I, A, or E)
• Minerals are “leached” into this layer from H2O moving downward
• Accumulation of elluvial organic matter
• Often high in iron, aluminum, and calcium
• Often high in clay content
• Unweathered parent material
• Shows little or no sign of soil formation (primary succession)
• Glacial deposits, volcanic ash
• Reveals history of the land
Texture
Sand 2.0-.02 mmSilt .02-.002 mmClay.002mm ≥ some microscopic
Porosity and Permeability
LOAM: 40%sand 40% silt 20% clay
Loam is theoretically the ideal soil
ltpwww.gsfc.nasa.gov/ globe/pvg/texture3.htm
Classes of SoilMollisols- very fertile, dark, found in temperate grasslands, best agricultural soil, Deep A horizonOxisols- soil of tropical and subtropical rainforest layer of iron and Al oxides in B horizon, little O horizonAlfisols- weathered forest soil, not deep, but developed OAE+B typical of most temperate forest biome. Need fertilizer for agricultureAridsols- dry lands + desert, lack of vegetation, lack of rain unstructured vertically, irrigation leads to salinization because of high evaporation.
The Public Policy and Soil
Low Input sustainable Agriculture (LISA)-started by US Defense of Agriculture in 1988
Conservation Reserve Program- 1985
Food Security Act of 1985
Federal Agriculture Improvement and Reform (FAIR) 1996
Environmental Quality Incentive Program (EQUIP)
Know these Acts and Laws:
LOAM: 40%sand 40% silt 20% clay
Loam is theoretically the ideal soil
ltpwww.gsfc.nasa.gov/ globe/pvg/texture3.htm