Soils:

1. Soils: A Natural Capital or Natural Resource!

2. Some call it dirt…..But it is Soil !!! Soil is made of loose, weathered rock and organic material.

3. The rock material in soil contains three noticeable parts: sand, clay, and silt.

4. Soil consists of: 45% mineral 25% water 25% air and 5% organic matter. This is just an average!

5. Soil Texture the way various soil particles clump together. Good soils: 2/3 of intra-soil spaces contain air after excess water has drained. • Friable - Crumbles easily.

6. Texture • Effects water holding capacity • Nutrient retention and supply • Drainage • leeching

7. Soil Structure • When individual particles clump or group together – depends on particle types, size, and how many pores are in between.

8. Question Break! Soil that has the feel of clay is that soils A: structure B. Texture

9. TEXTURE!!!!

10. There are thousands of different soils throughout the world. Five important factors influence the specific soil that develops.

11. Parent Material This refers to the minerals present during the formation of the soil.

12. Physical Fragmentation: the breaking up of rocks.

13. Parent Material Materials from volcanoes, sediment transported by wind, water, or glaciers are some examples.

14. Mineral Composition • Soils are made of: MINERALS

15. Geological Processes • Earths processes like volcanic reactions, earth quakes, tsunamis….

16. Weathering:Processes that bring about fragmentation or chemical change • Biological (plants and fungi) • Chemical (oxidation & water) • Physical (frost/thaw actions-erosion)

17. Question Break!

18. Think about the soils in our area. Where do you think our “parent material” came from?

19. Our parent material is mainly Marine sediment (ocean in origin), or produced by steam-river action. Also from the Appalachians. It may be thousands of feet deep!

20. Climate The climate of a particular region can have a major influence on the rate of soil formation.

21. Climate Weathering processes like the cycles of freezing and thawing, along with wetting and drying vary with each region.

22. Living Organisms Enriched by organic material from plants & animals with microbes and macrobes .

23. Living Organisms As they die, organic matter incorporates with weathered parent material and becomes part of the soil.

24. ORGANIC COMPONENT • As humus layer decays, nutrients are recycled back to plants

25. ORGANIC COMPONENT • HUMUS(sticky brown residue from partially decomposed plants and animals) • Humus creates “structure”- how particles cling together • Humus holds minerals in soil

27. Question Break!

28. Can you think of some organisms that might help mix and enrich the soil?

29. Living Organisms The actions of moles, earthworms, bacteria, fungi, and round worms mix and enrich the soil.

32. Other Factors Influencing Soil Formation: • Plant Roots • Bacteria and Fungi (Decomposers) • Position on Slope • Climate • Time • Rainfall • Soil pH • Topography

33. Topography The slope or hilliness of a region can have a major influence on the moisture and erosion of soils.

34. Topography In many regions, moist, poorly drained soils are located in low areas.

35. Topography Drier, well drained soils are often found in sloping hillsides. Erosion is often a problem here and can lead to lose of topsoil.

36. Topographic Maps

37. Each color change represents a 50 meter increase.

38. Time It takes hundreds of years to form one inch of soil from parent material.

39. Time Only the top few centimeters are productive in the sense of being able to sustain plant growth.

40. Time This is why soil conservation is so important!

41. Soil Profile: From Chapter 1 • Soil Profile - A series of horizontal layers of different chemical composition, physical properties, particle size, and amount of organic matter. • Each recognizable layer of the profile is known as a horizon. Our soil is a Natural Capital

42. Soil Profile In a cross-section of soil, various zones are formed.

43. O Horizon: Organic Layer It consists of leaf litter and other organic material lying on the surface of the soil.

44. A Horizon: Topsoil This layer is usually loose and crumbly with varying amounts of decayed organic matter.

45. A Horizon: Topsoil This is generally the most productive layer of the soil. Conservation efforts are focused here!

46. B Horizon: Subsoils Subsoils are usually lighter in color, dense and low in organic matter.

47. C Horizon: Transition This layer of transition is almost completely void of organic mater and is made up of partially weathered parent material.

48. Bedrock Below the C horizon the unweathered bedrock will be found.

49. Soil Profiles • Over 15,000 separate soil types have been classified in North America. However, most cultivated land can be classified as either grassland or forest soil. • Grassland Soils - Usually have a deep A Horizon - low rainfall limits topsoil leaching. • A Horizon supports most root growth.

50. Soil Profiles • Forest Soils - Topsoil layer is relatively thin, but topsoil leachate forms a subsoil that supports substantial root growth. (High rainfall areas) • Tropical Rainforests • Two features of great influence: • High Temperatures • Rapid decomposition, little litter. • High Rainfall • Excessive leaching of nutrients.