PA Soils
Did you know… <ul><li>It takes 550 years to make 1 inch of soil! </li></ul>
What is soil? <ul><li>The unconsolidated mineral or organic material on the immediate surface of the earth that serves as ...
What are the 4 main components of soil? <ul><li>1.  Minerals </li></ul><ul><li>2.  Water </li></ul><ul><li>3.  Air </li></...
What are soil horizons? <ul><li>Soil horizons are distinct horizontal layers in the soil that have differing characteristi...
The major soil horizons include… <ul><li>O horizon  </li></ul><ul><li>A horizon  </li></ul><ul><li>E horizon </li></ul><ul...
O Horizon <ul><li>top, organic layer of soil (can still recognize leaves as leaves) </li></ul>
A Horizon <ul><li>Normally referred to as top soil.  </li></ul><ul><li>This is where plant roots prefer to grow.  </li></u...
E Horizon <ul><li>Zone of eluviation </li></ul><ul><li>Clay is leached out of this layer so it is lighter in color than th...
B Horizon <ul><li>Zone of accumulation </li></ul><ul><li>Where leached clay from E horizon accumulates </li></ul><ul><li>T...
C Horizon <ul><li>Slightly broken up bedrock </li></ul><ul><li>Plant roots do not normally reach C horizon </li></ul>
R Horizon <ul><li>Unweathered rock </li></ul>
 
 
5 soil forming factors <ul><li>1.  Parent material - material in which the soil forms. </li></ul><ul><li>2.  Climate - tem...
Soil Texture <ul><li>Soil texture is the percentage of sand, silt, and clay in a given soil. </li></ul>
Soil Texture
Soil particle sizes <ul><li>Sand   </li></ul><ul><li>.2 mm - .05mm </li></ul><ul><li>Silt  </li></ul><ul><li>.05mm - .002m...
Why is soil texture important? <ul><li>The texture of the soil affects many processes that occur within the soil such as i...
<ul><li>Sand:  Largest particle size, fastest infiltration rates, lowest WHC </li></ul><ul><li>Silt:  Medium particle size...
What is soil structure? <ul><li>Soil structure is the arrangement of soil particles into peds (peds = individual unit of s...
 
Soil structures <ul><li>Granular  - common in A horizon - best structure for roots to grow in. </li></ul>
<ul><li>Platy  - found in B horizon and in compacted soils.  Really bad for plant roots! </li></ul>
Blocky soil structure <ul><li>Blocky  - Found in subsurface horizons  </li></ul><ul><li>Below the A horizon </li></ul>
Columnar soil structure <ul><li>Columnar  - vertical columns of soil that have a salt “cap” at the top.  Found in arid cli...
Prismatic soil structure <ul><li>Prismatic  - vertical columns of soil, usually found in subsurface horizons. </li></ul>
Massive soil structures <ul><li>Massive  - Soil with no visible structure, very large clods. </li></ul>
What is soil organic matter (SOM)? <ul><li>Plants and animals in  </li></ul><ul><li>various stages of </li></ul><ul><li>de...
<ul><li>SOM increases water holding capacity, infiltration rates, improves compaction, binds harmful pesticides and heavy ...
What is CEC? <ul><li>Common cations (positively charged ions) found in soil: silicon, aluminum, iron, magnesium, calcium, ...
<ul><li>Soil pH is an indication of the acidity or alkalinity of the soil. </li></ul><ul><li>Acid pH =0 - 7 </li></ul><ul>...
Soil erosion <ul><li>The loss of soil from the landscape.  Caused by: </li></ul><ul><ul><li>Water: sheet, rill and gully <...
Sheet <ul><li>Removal of a uniform thin layer of soil by raindrop splash or water run-off </li></ul>
Rill <ul><li>Removal of soil by concentrated water running through little streamlets </li></ul>
Gully <ul><li>Severe erosion in which trenches are cut to a depth greater than 1 foot. </li></ul>
Dust Bowl <ul><li>The natural deep-roooted grasses that normally kept the soil in place and trapped moisture even during p...
Conservation practices <ul><li>Riparian buffers  - planting of trees/shrubs along streambanks to filter or stabilize soil ...
<ul><li>Filter Strips  - Strips of grass used to trap sediment and chemicals before reaching a body of water. </li></ul><u...
<ul><li>Contour Farming  plowing across the slope and with the contour of the field. </li></ul>
Soil compaction <ul><li>When soil particles are pressed together, reducing the pore space between them </li></ul><ul><li>S...
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Soils

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Soils

  1. 1. PA Soils
  2. 2. Did you know… <ul><li>It takes 550 years to make 1 inch of soil! </li></ul>
  3. 3. What is soil? <ul><li>The unconsolidated mineral or organic material on the immediate surface of the earth that serves as a natural medium for plant growth. </li></ul>
  4. 4. What are the 4 main components of soil? <ul><li>1. Minerals </li></ul><ul><li>2. Water </li></ul><ul><li>3. Air </li></ul><ul><li>4. Organic </li></ul><ul><li>matter </li></ul>
  5. 5. What are soil horizons? <ul><li>Soil horizons are distinct horizontal layers in the soil that have differing characteristics. Not all soils have all horizons </li></ul>
  6. 6. The major soil horizons include… <ul><li>O horizon </li></ul><ul><li>A horizon </li></ul><ul><li>E horizon </li></ul><ul><li>B horizon </li></ul><ul><li>C horizon </li></ul><ul><li>R horizon </li></ul>
  7. 7. O Horizon <ul><li>top, organic layer of soil (can still recognize leaves as leaves) </li></ul>
  8. 8. A Horizon <ul><li>Normally referred to as top soil. </li></ul><ul><li>This is where plant roots prefer to grow. </li></ul><ul><li>It is darker in color that the horizons below! </li></ul>
  9. 9. E Horizon <ul><li>Zone of eluviation </li></ul><ul><li>Clay is leached out of this layer so it is lighter in color than the A or B horizon. </li></ul><ul><li>There is not much of this in PA! </li></ul>
  10. 10. B Horizon <ul><li>Zone of accumulation </li></ul><ul><li>Where leached clay from E horizon accumulates </li></ul><ul><li>Thick and sticky with clay! </li></ul>
  11. 11. C Horizon <ul><li>Slightly broken up bedrock </li></ul><ul><li>Plant roots do not normally reach C horizon </li></ul>
  12. 12. R Horizon <ul><li>Unweathered rock </li></ul>
  13. 15. 5 soil forming factors <ul><li>1. Parent material - material in which the soil forms. </li></ul><ul><li>2. Climate - temperature and rainfall affect the amount of weathering. **Water is crucial for chemical weathering of bedrock. </li></ul><ul><li>3. Biological Factors - plants and animals contribute to organic fraction of soil, and help breack down rocks and rock fragments. </li></ul><ul><li>4. Topography - slope and aspect affect temperature of soil </li></ul><ul><li>5. Time - soil formation is a continuous process affected by flooding, etc. </li></ul>
  14. 16. Soil Texture <ul><li>Soil texture is the percentage of sand, silt, and clay in a given soil. </li></ul>
  15. 17. Soil Texture
  16. 18. Soil particle sizes <ul><li>Sand </li></ul><ul><li>.2 mm - .05mm </li></ul><ul><li>Silt </li></ul><ul><li>.05mm - .002mm </li></ul><ul><li>Clay </li></ul><ul><li>less than .002 </li></ul>
  17. 19. Why is soil texture important? <ul><li>The texture of the soil affects many processes that occur within the soil such as infiltration rates and water holding capacity (WHC). </li></ul><ul><li>WHC - is how well the soil stores the water once it ets in there! </li></ul>
  18. 20. <ul><li>Sand: Largest particle size, fastest infiltration rates, lowest WHC </li></ul><ul><li>Silt: Medium particle size, medium infiltration rates, medium WHC </li></ul><ul><li>Clay: Smallest particle size, slowest infiltration rates, highest WHC </li></ul><ul><li>Infiltration - how fast the water enters the soils surface! </li></ul>
  19. 21. What is soil structure? <ul><li>Soil structure is the arrangement of soil particles into peds (peds = individual unit of soil structure). </li></ul><ul><li>Types of soil structure include: granular, platy, blocky, columnar, prismatic, and massive </li></ul>
  20. 23. Soil structures <ul><li>Granular - common in A horizon - best structure for roots to grow in. </li></ul>
  21. 24. <ul><li>Platy - found in B horizon and in compacted soils. Really bad for plant roots! </li></ul>
  22. 25. Blocky soil structure <ul><li>Blocky - Found in subsurface horizons </li></ul><ul><li>Below the A horizon </li></ul>
  23. 26. Columnar soil structure <ul><li>Columnar - vertical columns of soil that have a salt “cap” at the top. Found in arid climates. </li></ul>
  24. 27. Prismatic soil structure <ul><li>Prismatic - vertical columns of soil, usually found in subsurface horizons. </li></ul>
  25. 28. Massive soil structures <ul><li>Massive - Soil with no visible structure, very large clods. </li></ul>
  26. 29. What is soil organic matter (SOM)? <ul><li>Plants and animals in </li></ul><ul><li>various stages of </li></ul><ul><li>decomposition. </li></ul>
  27. 30. <ul><li>SOM increases water holding capacity, infiltration rates, improves compaction, binds harmful pesticides and heavy metals, and provides energy for soil microbes. </li></ul><ul><li>Tilage decreases SOM content in the soil because it increases the decomposition rates. </li></ul>
  28. 31. What is CEC? <ul><li>Common cations (positively charged ions) found in soil: silicon, aluminum, iron, magnesium, calcium, sodium, potassium </li></ul><ul><li>Common anion (negatively charged ions) in soil: oxygen </li></ul>
  29. 32. <ul><li>Soil pH is an indication of the acidity or alkalinity of the soil. </li></ul><ul><li>Acid pH =0 - 7 </li></ul><ul><li>Neutral pH =7 </li></ul><ul><li>Alkaline (basic) pH = 7 - 14 </li></ul><ul><li>Most plants prefer to grow where the soil pH is around 6 - 7. </li></ul><ul><li>If soil pH is too low, lime can be added to raise the soil pH </li></ul>
  30. 33. Soil erosion <ul><li>The loss of soil from the landscape. Caused by: </li></ul><ul><ul><li>Water: sheet, rill and gully </li></ul></ul><ul><ul><li>Wind: Dust bowl </li></ul></ul><ul><ul><li>Man/mechanical: construction sites </li></ul></ul>
  31. 34. Sheet <ul><li>Removal of a uniform thin layer of soil by raindrop splash or water run-off </li></ul>
  32. 35. Rill <ul><li>Removal of soil by concentrated water running through little streamlets </li></ul>
  33. 36. Gully <ul><li>Severe erosion in which trenches are cut to a depth greater than 1 foot. </li></ul>
  34. 37. Dust Bowl <ul><li>The natural deep-roooted grasses that normally kept the soil in place and trapped moisture even during periods of drought and high winds was removed. </li></ul><ul><li>During the drought of the 1930s, without natural anchors to keep the soil in place, it dried, turned to dust, and blew away eastward and southward in large dark clouds. </li></ul>
  35. 38. Conservation practices <ul><li>Riparian buffers - planting of trees/shrubs along streambanks to filter or stabilize soil and reduce soil erosion </li></ul>
  36. 39. <ul><li>Filter Strips - Strips of grass used to trap sediment and chemicals before reaching a body of water. </li></ul><ul><li>Grassed waterways - strips of grass in areas where water concentrates or flows off of a field. </li></ul>
  37. 40. <ul><li>Contour Farming plowing across the slope and with the contour of the field. </li></ul>
  38. 41. Soil compaction <ul><li>When soil particles are pressed together, reducing the pore space between them </li></ul><ul><li>Soil compaction is caused by wheel traffic and tilling soil. </li></ul><ul><li>Soil compaction reduces water infiltration and plant growth! </li></ul>

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