Soil: Components, Formation, and Functions

1. Components and Properties of Soil

2. What is soil? Material which nourishes and supports growing plants includes rocks, water, organic material and air.

3. How is soil formed? Rocks rubbing together for many, many years Organic matter

4. What is our State…… • Soil….. • Jory • Rock….. • Thunder Egg

5. What is the function of soil? • Plant medium • Recycling system for nutrients • Habitat for organisms • System for water supply • Water purification • Support foundation • Heat storage • Decomposes organic material • Buffer of toxic compounds to the environment • Source of raw materials • Gene pool • Source of history

6. Soil Formation - Parent Material Parent Material is the “base” material that a soil is formed from. Soil Soils are the product of the effects of climate, topography, and living organisms acting on parent material over a period of time.

7. Soil Horizons • As soils develop by forming layers called Horizons.

8. O Horizon • Layer of accumulated organic matter such as leaves, grass, twigs • Material can be in various states of decomposition • Generally dark in color O A E B C R

9. A Horizon • Generally is the most productive horizon • High biological activity • Dark in color • Topsoil O A E B C R

10. E Horizon • Leached soil • Soluble minerals and organic material move out of this horizon • Lighter “washed” appearance in color O A E B C R

11. B Horizon • Less amount of parent material break down and organic matter. • More course fragments (rock visible) • Varies in color from reds and yellows to browns and grays O A E B C R

12. C Horizon • The unconsolidated material that has been affected little by the soil forming processes • Course fragments present O A E B C R

13. R Horizon • Hard bedrock • 100% course fragments, also known as rock O A E B C R

15. Assignment • You will make a “Soil Profile Flipbook” • Each horizon will be on a different flap • You must have the following: • Name of the horizon • Description and characterizes of the horizon • Color of the horizon • Soil profile • Make it colored

16. What is a soil Profile Review http://www.youtube.com/watch?v=6Kr3Wj7SeSc

17. Soil Differs in: • Texture • Color • Structure • Consistence • Fertility and Productivity

18. Soil Texture • The way soil feels • Based on the relative proportions of each size of soil particle • Sandy loam, Silty loam, Sandy Clay loam

19. Why is soil texture important? • Influences many soil properties • drainage, water holding capacity, aeration, susceptibility to erosion, organic matter content, cation exchange capacity, pH buffering capacity, and soil tilth

20. Sand (0.05-2.00 mm) Silt (0.002-0.05 mm) Clay (<0.002 mm) Soil Texture - Relative Sizes of Soil Particles

21. Sand • Larger particles in the soil • Can be seen with the naked eye • Not fertile • Quick to dry out and are doughy • Drain quickly

22. Silt • Between sand and clay particles in size, medium size • Provide few nutrients to plants • Erode very easily • Moderate drainage

23. Clay • Smallest of the soil particles • Hold soil nutrients • Hold more moisture than either sand or silt • Dry out slowly • Become cloddy unless properly managed

24. What is loam? The Best of All Worlds • A soil type that contains all three particle sizes. • The most productive soil for farming crops • Has good water holding capacity (from clay) • Has good drainage (from sand) • Can be nutritious (from silt)

25. 12 Soil Texture Classes • Sand (S) • Loamy Sand (LS) • Sandy Loam (SL) • Loam (L) • Silt Loam (SIL) • Silt (SI) • Sandy Clay Loam (SCL) • Silty Clay Loam (SICL) • Clay Loam (CL) • Sandy Clay (SC) • Silty Clay (SIC) • Clay (C) Compositions of each of the 12 texture classes is defined by the USDA Soil Triangle

26. Soil Texture

27. Soil Triangle http://www.youtube.com/watch?v=VEgHmgnrWzk Take notes on what is being said

28. Soil Triangle Problems

29. Using the Soil Triangle find the following soils: Has to equal 100% at the end!! Clay Silt Sandy Loam

30. Worksheet on your own