Natural Resources and Ecology Natural Resources and Ecology

Natural Resources and Ecology

Natural Resources and Ecology The Formation of Soils Unit 2 – Lesson 2. 1 Soils and Land

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

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

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

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

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

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

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

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

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

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.