Topic: Erosian and Soils
Type: Essay
Description: In well-written paragraphs, with complete citations, please discuss two geographic concepts we covered this week that you found most interesting, difficult, surprising, or otherwise noteworthy. Use personal experience, information from other courses, maps and other such information to help you provide your understanding of the concepts. Be sure to use two terms from the vocabulary lists at the beginning of each chapter (boldfaced in the text) in your discussion to show your knowledge of geography, and discuss them in your assessment. Please boldface the terms so they show clearly as content focal points in your work. You may use graphics as we practiced in last week's "Extra Credit" forum to help illustrate your points. If you do, please use only one or two items at most for these short assignments as more can overshadow your written contributions. Be sure to cite the text (for terms and concepts reference) and any source of graphics. Weekly Learning Objectives: Explain principles of mass wasting and weathering, the formation of landforms in the Arctic and alpine environments, and characteristics of soils. Chapter 10 Learning Objectives: 1. Explain the processes of physical and chemical weathering and how they lead to new landforms. 2. Explain how the forces at work on a slope define an angle of repose. 3. Describe soil creep, rock falls, landslides, flows and mass wasting. Chapter 15 Learning Objectives: 1. Describe the components of soil, characteristics of soil horizons, as well as processes of soil formation and development. 2. Explain soil properties, to include soil color, grain size, structure, and moisture. 3. Explain the importance of soil pH and soil colloids in soil chemistry. 4. Describe the characteristics of soil orders determined by maturity, climate and parent material.
Erosion and Soils-
Components of soil
It takes a long period of time for soil characteristic to develop through a variety of processes acting in unison. The usual soil comprises of 50% organic material and mineral and the other half open pores full of water and air. Certain physical processes crush down rock particles into even smaller pieces. Chemical processes then change the mineral composition of the parent rock material or sediment and end in new minerals. A number of things including plant roots, invertebrates and microbes mix and compost organic material and minerals into a novel matrix of soil. Together, these chemical, physical and biological processes are known as weathering. Such weathering processes, after a while, soften, fragment, and crush bedrock apart, thus forming a layer known as regolith. Other types of regolith include mineral particles transported by glaciers, streams, water currents, waves and winds. More often than not, the top layer of regolith weathers and forms soil. Thus, soil includes mineral from plants, vertebrate and invertebrate animals, microorganisms and rock material, as well. Some humus gets carried deep into the soil while some rests on the soil.
Soil properties
Soil can be categorized using properties like structure, color, texture and moisture. Color is the most palpable characteristic. While some soils are dark brown or black, others might be yellow or red. The color comes about during the process of soil formation. Soil structure, on its part, is the way in which soil grains clump together to form large masses referred to as peds, which range from small to large grains. Soils that have a well-developed blocky or granular structure can be easily cultivated. This factor can sustain the non-mechanized type of farming. Soil moisture is also another characteristic that defines soil. It determines how the soils of a certain region will support crops and general vegetation.
Reference- Strahler, A. H., & Strahler, A. N. (2006). Introducing physical geography. New York: J. Wiley.