1. Natural Resources and Ecology

2. The Formation of Soils Unit 2 – Lesson 2.1 Soils and Land

3. Soil Forming Factors Five factors acting together influence the formation of soil: Parent Material Climate Organisms Topography Time

4. Parent Material Original mineral from which soil develops Influences soil fertility and texture Sources of parent material –Minerals and rocks –Deposits – glacial, wind, water, and organic

5. Climate and location affect the rate of weathering. Weathering breaks down rock into smaller fragments and eventually down to small particles. Climate Temperature Rainfall

6. Organisms Macro-organisms (living and dead) –Source of organic matter –Large plants and animals Microorganisms –Microscopic plants and organisms –Primary decomposers of organic material

7. Topography Affects distribution of soil particles and water Slope causes water runoff and potential erosion Water moves smaller soil particles down the slope

8. Time Highly variable rate of formation Different types of parent material weather at different rates Climate and topography also influence rate of soil formation

9. Erosion The opposite of soil formation is erosion, which has a detrimental effect on soil. Erosion is a natural process. Erosion comes in two forms: Water Wind

10. Erosion Happens In what circumstances is soil erosion more likely to happen? Steep ground Excessive water movement Little or no vegetation Wind blowing across bare soil

11. Soil Development There are four main ways that the process of soil formation occurs: Addition – accumulation or deposition Reduction – leaching and erosion Translocation – movement within soil profile Transformation – soil changes in place by weathering or microorganism conversion

12. References Burton, L. D. (2009). Environmental science: Fundamentals and applications. Clifton Park, NY: Delmar Cengage Learning. Huddleston, J. H., & Kling, G. F. (1996). Manual for judging Oregon soils. Corvallis, OR: Oregon State University. Parker, R. (2010). Plant and soil science: Fundamentals and applications. Clifton Park, NY: Delmar.