Soils Test Review

1. Soils Test Review Advanced Plant & Soil Science

2. Why is soil important? • Basis for all natural ecosystems • Place for plant growth • Provides nutrients and water • Home for animals • Basis of production agriculture • Place for plant growth • Food for animals

3. List and explain the five factors that control soil formation. • Parent Material—rock or other material from which soil formed • Time—slow process • Climate—affects soil depth, weathering rates & organic matter • Vegetation—affects organic matter • Topography—affects permeability & erosion

4. List and describe the three types of parent materials. • Residual—develop from underlying bedrock material • Transported—parent materials are moved • Cumulose—organic materials

5. List and describe the five types of transported materials. • Alluvial—sediments transported by flowing water of streams/rivers • Marine—sediments washed out to sea by rivers & later lifted above sea level • Eolian—sediments moved by wind • Loess—silt deposited during strong winds • Colluvial—parent materials that move by sliding or rolling down a slope

6. What is physical weathering? • The natural process by which rock is broken into smaller pieces • “mechanical weathering”

7. Which forces of nature are involved in the physical weathering process? • Temperature • Water • Wind • Plants & Animals

8. What is chemical weathering? • Changes the chemical make-up of rock and further breaks it down • Typically involves water, oxygen, or carbon

9. Give examples of chemical weathering. • Solution • Hydrolysis • Oxidation • Rust • Carbonic Acid Action

10. What is the composition of a typical soil? • 45% Mineral Materials • 5% Organic Material • 25% Water • 25% Air

11. What are the three types of soil particles? • Sand—0.052.0 mm • Silt—0.0020.05 mm • Clay-- <0.002 mm

12. What determines soil texture? • The proportion of sand, silt & clay in the soil

13. Name and explain the method that can be used to determine soil texture. • Ribbon Test • Dampen soil • Work in hand • Try to push soil into a ribbon

14. Draw an example of a soil profile, complete with horizons and layer titles.

15. When determining soil depth, what is considered? • The total depth of the layers that will allow growth of plant roots

16. Draw and label each of the six soil structures discussed in class.

17. What does soil permeability mean? • The ability of soil to absorb water and the ability of water to move in the soil

18. Soil permeability is based upon what? • Structure, texture, cracking, and other soil features

19. What is meant by soil salinity? • Total amount of salts in the soil

20. In what type of environment is soil salinity more likely to be high? • Areas that have low annual rainfall

21. Explain how soil salinity affects plants. • Can inhibit water absorption by the roots • Raises the osmotic pressure

22. What are the factors that influence soil pH? • Parent Material • Amount of rainfall • Erosion • Removal of calcium and magnesium by crops

23. Explain the influence of pH on plant growth. • Affects the reaction between soil and plants • Some nutrients are not available at certain pH levels

24. How can soil pH be modified? • Acidic soils = apply lime • Alkaline soils = apply sulfur

25. Describe the two methods of wind erosion discussed in class. • Wind—movement of particles by wind • Saltation—movement in short bounces • Surface creep—particles pushed along • Water—movement of particles by water

26. Explain the three stages of water erosion. • Detachment—falling drops of water detaches a soil particle from the topsoil • Splash Erosion • Transportation—run-off; soil is unable to absorb anymore water, so soil is carried away • Deposition—soil is deposited after water slows or is absorbed

27. Describe the two types of erosion caused by running water. • Rill Erosion—topsoil removed in thin layers • Gully Erosion—deep ditches formed

28. What landforms are created by water erosion? • Gullies • Beaches • River Valleys

29. List the factors that influence soil erosion. • Soil texture • Soil depth • Organic matter content • Climate • Vegetative cover • Slope & horizontal length • Soil management

30. List and describe control measures for soil erosion. • Efficient land use—use the land to maximize income with minimum damage to the land • Water disposal systems—minimize runoff and ersion • Contour Farming • Terraces • Strip Cropping • Crop Rotation • Water Outlets • Diversion Ditches or Levees • Cover crops—hold together loose soil and increase water infiltration and absorption • Conservation tillage—leave significant amounts of residue on the soil surface during the entire year • Fertilization & liming—help with faster root development • Gully control—prevent gullies from occurring with proper retention or diversion • Erosion control plan—a plan for controlling erosion on a particular piece of land

31. Identify four questions that should be considered when developing an erosion control plan. • What effect does erosion have on the value of the land? • What effect does erosion have on current & future agriculture production? • How are other landowners facing erosion problems? • What is the nature of the soil? • What erosion control practices are recommended? • Are planned erosion control practices cost effective? • What will be the costs of not using erosion control practices? • What are the benefits to be realized from erosion control? • What plans are formulated to implement the erosion control plan?