Soil properties


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Soil Properties
Fruit and Vegetable Science
K. Jerome

Published in: Education

Soil properties

  2. 2. Components of soil <ul><li>Texture – amounts of sand, silt, clay particles </li></ul><ul><li>almost pure sand </li></ul><ul><li>sandy loam </li></ul><ul><li>silt loam </li></ul><ul><li>clay </li></ul>
  3. 3. Components of soil <ul><li>Soil Texture Affects: </li></ul><ul><ul><li>Infiltration rate </li></ul></ul><ul><ul><li>Drainage </li></ul></ul><ul><ul><li>Nutrient storage </li></ul></ul><ul><ul><li>Ease of seedling emergence </li></ul></ul><ul><ul><li>Ease of root penetration </li></ul></ul>
  4. 4. Components of soil <ul><li>Aggregates – clumps of soil held together </li></ul><ul><li>Aggregation is </li></ul><ul><li>GOOD </li></ul>
  5. 5. Cycles that affect plant growth <ul><li>Temperature: </li></ul><ul><li>most roots grow when soil temperature is above 40°F to 50°F </li></ul><ul><li>seed germination depends on soil temperature </li></ul>
  6. 6. Cycles that affect plant growth <ul><li>Gasses: </li></ul><ul><li>Plants need oxygen </li></ul><ul><li>Give off carbon dioxide </li></ul><ul><li>Soil helps maintain proper amounts of oxygen, carbon dioxide </li></ul>
  7. 8. Cycles that affect plant growth <ul><li>Water: </li></ul><ul><li>stored in soil pores </li></ul><ul><li>  s oil filters, purifies water </li></ul>
  8. 10.   Cycles that affect plant growth <ul><li>Carbon: </li></ul><ul><li>Plants collect energy from sun to perform photosynthesis </li></ul><ul><li>Convert atmospheric carbon into biological carbon </li></ul><ul><li>Recycled by organic matter decay in soil </li></ul>
  9. 12.   Medium for plant growth <ul><li>Plants need four things from soil:   Anchorage </li></ul><ul><li>Water </li></ul><ul><li>Oxygen </li></ul><ul><li>Nutrients </li></ul>
  10. 13. Anchorage <ul><li>Soil must hold plants in place </li></ul><ul><li>deep soil - firm support, anchorage </li></ul><ul><li>shallow soil or poor holding capacity – </li></ul><ul><li>artificial support required </li></ul>
  11. 14.   Water <ul><li>Roots absorb water </li></ul><ul><li>better than leaves </li></ul><ul><li>Water-holding capacity critical for growth </li></ul><ul><li>200-1000 pounds water used for every pound of dry plant matter produced </li></ul>
  12. 15. Oxygen <ul><li>All living things need oxygen </li></ul><ul><li>Plants roots consume oxygen in soil during respiration, give off carbon dioxide (CO 2 ) </li></ul><ul><li>Replace it with carbon dioxide </li></ul>
  13. 16.   Aeration <ul><li>Process by which carbon dioxide and oxygen exchanged in soil to provide plants with oxygen.   </li></ul><ul><li>Waterlogged soil has no aeration, no oxygen for plants; causes root hairs to die.   </li></ul>
  14. 17. Nutrients <ul><li>Plants need 17 nutrients; 14 come from soil   </li></ul><ul><li>Carbon, oxygen, hydrogen come from air and water </li></ul>
  15. 18. Nutrients <ul><li>Root hairs absorb plant nutrients dissolved in soil solution </li></ul><ul><li>Energy that powers uptake produced by root respiration </li></ul>
  16. 19. Makeup of soils <ul><li>Soil made of solid </li></ul><ul><li>particles </li></ul><ul><li>Consist largely of minerals </li></ul><ul><li>1 to 10 percent organic matter </li></ul>
  17. 20. Makeup of soils <ul><li>Pore spaces – voids, open spaces between solid particles </li></ul><ul><li>  </li></ul><ul><li>Usually, half soil volume is solid and half is pore space   </li></ul>
  18. 21. Root Growth <ul><li>The health of the entire plant depends on the health of its root system. </li></ul>
  19. 22.   Root Growth <ul><li>  R oots follow continuous pore spaces between solid particles   Root tips easily penetrate larger pores, must exert pressure to penetrate small pores </li></ul>
  20. 23.   Root Growth <ul><li>Tree roots cover area 60-100 percent beyond spread of tree canopy </li></ul><ul><li>Roots grow to 5-6 feet down; no oxygen below this point  </li></ul>
  21. 24. Root Growth <ul><li>Most roots in upper one foot of soil where greatest amount of oxygen is found </li></ul><ul><li>Roots will grow </li></ul><ul><li>toward water and </li></ul><ul><li>nutrients </li></ul>
  22. 25. Root Growth <ul><li>Limited by: </li></ul><ul><li>hardpan </li></ul><ul><li>bedrock </li></ul><ul><li>soil salt </li></ul><ul><li>low nutrients </li></ul><ul><li>high water </li></ul><ul><li>low water </li></ul><ul><li>toxic materials </li></ul><ul><li>temperature extremes   </li></ul>
  23. 26. Soil health <ul><li>Capacity of soil to sustain plant and animal growth </li></ul><ul><li>Capacity of soil to maintain air and water quality </li></ul>
  24. 27. Tilth <ul><li>Physical condition of tilled soil </li></ul><ul><li>How easy soil is to till? </li></ul><ul><li>What kind of seedbed can be made? </li></ul><ul><li>How easily seedlings will come up? </li></ul><ul><li>How easily can roots push through the soil? </li></ul>
  25. 28. Tilth <ul><li>Tilling improves tilth in fine-textured soil because increases air spaces </li></ul><ul><li>Over time, tilling destroys soil structure </li></ul>
  26. 29. COMPACTION <ul><li>Pressure applied to soil surface - collapses particles into pores </li></ul><ul><li>Dry soil less vulnerable to compaction than wet soil </li></ul>
  27. 30. COMPACTION <ul><li>Profoundly alters soil structure: </li></ul><ul><li>Particles squeezed together </li></ul><ul><li>Roots need more pressure to get through </li></ul>
  28. 31. COMPACTION <ul><li>Reduced permeability </li></ul><ul><li>Reduced air exchange </li></ul><ul><li>Reduced infiltration </li></ul><ul><li>Reduced microbial activity because of loss of oxygen </li></ul>
  29. 32. COMPACTION <ul><li>Annual tilling breaks up soil at surface, </li></ul><ul><li>makes tillage pan which is impenetrable </li></ul><ul><li>Heavy equipment makes </li></ul><ul><li>compaction worse </li></ul><ul><li>Decreases yields </li></ul><ul><li>Working wet soil compounds </li></ul><ul><li>problem </li></ul>
  30. 33. Improving tilth <ul><li>Never work wet or dry soils </li></ul><ul><li>Control traffic in fields </li></ul><ul><li>Reduce amount of tillage </li></ul><ul><li>Keep soil covered by vegetation </li></ul>
  31. 34. Improving tilth <ul><li>Crop rotation </li></ul><ul><li>Add organic </li></ul><ul><li>material - green </li></ul><ul><li>manure </li></ul><ul><li>Chisel plow to go really deep </li></ul>
  32. 35. How much soil is there? <ul><li>How Much Soil Is There? </li></ul>