Introduction to Soil Erosion, Summaries of Environmental Science

Download Introduction to Soil Erosion and more Summaries Environmental Science in PDF only on Docsity! LESSON ONE Introduction to Soil Erosion NORTH CAROLINA STATE UNIVERSITY 4!H PLANT AND SOIL SCIENCES Skill Level Advanced; ages 14-18 Learner Outcomes Students will broadly explore soil erosion to understand the physical mechanisms behind the process of erosion and the impacts that sediment has on water quality. Students will form a scienti!c learning community and share their ideas and !ndings through a blog. Time Needed One 90-minute class or two 45-minute classes National Science Education Standards Science in Personal and Social Perspectives (Content Standard F) Natural Resources, Environmental Quality, Natural and Human Induced Hazards Success Indicator Describe how erosion impacts water quality Life Skills Teamwork Critical "inking Record Keeping Communication Materials Lesson One Teacher PowerPoint (www.growforit.org/soiltoseed) Computer LCD projector Internet access Copies of handouts (at end of lesson) Fi#een, 16-oz paper or styrofoam cup with white interior 15, 10 or 15ml pipe$es 4-5 turkey basters 15 cups of soil Water Logistics Note Students will be asked to work in teams of 5 or 6 students on a number of assignments throughout this curriculum. 2 What role do humans play in this process? Humans can accelerate the erosion process through mismanagement of agricultural lands and the clearing activities caused by development, mining or logging. Why is it important to limit soil erosion? Loss of plant essential nutrients from the eroded topsoil reduces the productivity of agricultural lands and in urban development makes it hard to establish vegetation like lawns Sediment can carry polluting chemicals, destroy !sh habitats, decrease the storage capacity of water bodies and increase the risk of &ooding Sedimentation reduces recreational and municipal usefulness of water bodies and may require expensive dredging. A#er discussing student’s initial ideas about soil erosion, introduce the activities they will be doing throughout the soil erosion unit, from exploring the basic physics of soil movement and soil properties to designing experiments that will determine the best practices to control soil erosion and sedimentation, helping to protect water quality. Outline expectations for their learning, beginning by asking students about their own expectations and interest in the subject. Inform them they will be expected to work as a team of scientists, continually observing and asking questions and communicating their ideas to each other. "e students will be asked to record their ideas and experiences through a classroom blog or science journal. The Start of Soil Erosion Show the students the “Rain Splash” video (available for viewing and download at h!p://www.youtube.com/ user/soiltoseed). Ask the students to report on their observations. Questions throughout the video should prompt students to focus on key points. Teachers may want to show the video two or three times. Teachers might consider asking questions like: “What happened to the soil?” “How did the speed of the rain drop a%ect the soil movement?” “What role did soil particle size play in the dispersal distance?” “What happened when the larger rain drop hit the soil?” “Have you seen examples of this before?” “Why do you think this is important?” “What does this have to do with soil erosion?” Explain that the video shows the mechanics of soil erosion, detachment and then transport. "e physical impact by the raindrops causes the soil aggregates to break apart, leaving !ne soil particles that can be easily transported away by water runo%. In the videos, the !ner sand particles travel farther than the coarser particles because they are lighter and easier to move. "e students will have an opportunity to determine this themselves. 5 Soil Splash Test 4. Further explore variables that a%ect soil displacement by changing: a. "e height of the pipe$e (rainfall) b. "e volume of rainfall (use a di%erent water dropper, like a turkey baster) c. "e slopes of the splash test 5. Observe di%erences in splash e%ect between the variables. Plot your measurements on the Splash Test Data Sheet and possibly on the chalkboard as well to share results of their experimentation with the entire class. 7. Repeat this experiment with another soil texture and record measurements on another Soil Splash Test Data Sheet. "e soil splash test lends itself to multiple variations, as a group come up with additional ideas to test. You might try additional soil textures or soils with strong structure. What conditions cause soil erosion? How do di%erent soil erosion factors a%ect soil displacement? How can you play a role in managing soil erosion? Complete this experiment to discover what variables play a role in the erosion of soil. Do … the activity 1. In groups of two to three, place about a quarter cup of dry soil (one clay and one sand) in a small dish or plate. Alternatively, cut o% the bo$om of a paper cup to the height of 1-inch and !ll with soil. Using a large piece of white paper (easel pad) placed on the &oor (or the white back of a laminated poster/ piece of paper), place the plate with the dry sandy soil in the center. 2. Have one person from each group !ll a pipe$e with water and from a height of about 4’ release the water from the pipe$e aiming for the soil pile. Record your measurements of how far soil is displaced when it is dry. 3. Continue to rain on the soil until the point of saturation. Once the soil is saturated, observe soil particles that have been displaced from the plate onto the white paper. Measure the distance that some of the particles have traveled using a ruler and record your !ndings on the Splash Test Data handout. You may also choose to draw concentric circles on the paper, like a bullseye, with the rings providing a scale to measure the distance traveled by the soil particles. Name: ___________________________ Date: ____________________________ 6 Talking it Over: Soil Splash Test Share ...what you did What soils did you use in your experiment? What vari- ables did you change? How did the di%erent variables (height of rainfall, rain intensity, slope) a%ect soil dispersal? List the most surprising thing(s) you observed. Explain why you were surprised by these results Re"ect ...on the results Based on the results of your experiment, what factors cause signi!cant erosion? Explain. Based on the results of your experiment, explain the importance of managing soil erosion. Generalize ...to your community Based on the results of the splash test, how, if at all will you change the way you manage the soil at your school, your house, your community? Based on the results of your experiment, explain things you might look for when looking at sites that might be susceptible to erosion? Apply ...to your community Based on the knowledge you have gained from your experiment, how do you think soil should be managed to prevent erosion? Based on your new knowledge, what do you think you should do if you observe soil erosion occuring? 7 The Soil Erosion Blog Introduce the students to the concept of a classroom blog focused on soil erosion. Blogs are websites that contain text, video, photos, and audio postings on a particular subject. In the classroom, blogs o%er a relevant way for students to create a scienti!c community amongst themselves and the public, contributing ideas on a topic of learning, asking questions, and commenting on each other’s postings. A blog allows teachers to assess student understanding and participation. A science journal can serve a similar purpose and provides a good alternative for those with limited Internet access. "e public nature of a blog, however, opens student ideas for discus- sion with a potentially global audience, is well suited to multiple learning styles, encourages students to take pride in their work, fosters peer-to-peer interaction and learning, and allows mutual learning between teacher and students. If school policy limits blog use, consider pass- word protecting it and inviting only students to partici- pate. Teachers might collaborate with an English teacher or technology teacher to discuss document structure when blogging, Internet safety, or crediting information sources. Fig. 1-3. A student participating in the blogging portion of the lesson. As part of the soil erosion project, ask the students to participate in the blog as scientists and be responsible for recording observations, recapping the events and ideas of the day, taking and using photographs or video, and providing feedback to their peers through commenting. When introducing the idea of a blog to the students, solicit their ideas on how they would like to use it and what elements they feel are important to include (photos, links to articles, grammatical considerations and such) and use this information as the basis for assessment. A sample rubric (located at the end of this lesson) has been devel- oped for teachers and students to provide expectations and guidelines for blog posting. Also be sure to create a collective list of posting etique$e (language, bullying, crediting sources). A blog can be started using free online blogging so#ware. Possibilities to consider include; www.blogger.com, www. wordpress.com or www.livejournal.com. Teachers may prefer to set up one blog per class and have each blogger include his or her name as part of the post. Others may set up a blog per group. For an example of a high school class that blogged about their soil erosion experiences, visit: h$p://wake!eldsoil.blogspot.com/ Teachers might also pre-select a number of good science blogs to show as examples and highlight good features. Assessments #e Daily Blog: "e blog is an assignment given to students daily. Students will be capturing and summa- rizing the information they learn, comment on their peer’s postings and citing reference materials from experts. Teachers will assess student understanding using the rubric included at the end of this lesson. For Lesson One’s blog, teachers should have all students post to the blog to increase their familiarity with the medium, using their re&ections, questions about the day’s experiences as the content for their writing. See the previous section for more information regarding the daily blog. #e Word Wall: "e Word Wall is a matrix of de!nitions and terms that will be covered throughout the curriculum. Students should de!ne di%erent concepts and ideas through writing, drawing and graphing. Teachers can have the students complete the Word Wall as a graded assignment and measure student knowledge based on their given answers. 10 Pre-Test: A cumulative wri$en exam is located in the appendix at the end of the curriculum. Teachers can give the exam before beginning the curriculum to asses student levels of understanding and determine which areas they might focus their studying and as a way to show knowledge gain as a result of the curriculum instruction. Learning More Hugh Hammond Benne$ was born on a co$on farm in Anson County, North Carolina. A#er graduating from UNC-Chapel Hill, he took a position in the Bureau of Soils, within the U.S. Department of Agriculture. He began classifying and mapping soils throughout the Southeast and observing their productivity. He quickly noticed the impact soil erosion had on agricultural capacity and worked throughout his career to establish an awareness of what he considered a “national menace.” Benne$ was a !erce advocate for soil conservation practices, urging farmers to employ measures such as contour farming and terracing to manage the soil. With the devastating e%ects of the Dust Bowl in 1935, Benne$ urged congress to pass the Soil Conservation Act establishing the !rst Soil Conservation Service, and he was named chief of the new agency. One of his lasting legacies is the development of soil and water conservation districts at the county level to promote stew- ardship of the soil at the local level. Have students conduct further research into the life of Hugh Hammond Benne$. Encourage students to contact their county Soil and Water Conservation District and interview the district director about the conservation work the district does. Students should compile a list of questions they are interested in knowing more about in preparation for the interview. "ey could report their !ndings on the blog. Ask students to research the Dust Bowl and present their !ndings. References Toy, T. J., Foster, G.R., Renard, K.G. (2002). Soil erosion: processes, prediction, measurement, and control. New York, New York. Wiley. North Carolina Essential Science Standards EARTH/ ENVIRONMENTAL SCIENCE Essential Standard EEn.2.1: Explain how processes and forces a"ect the lithosphere Clarifying Objective EEn.2.1.3: Explain how natural actions such as weathering, erosion (wind, water and gravity), and soil formation a%ect Earth’s surface Essential Standard EEn.2.2: Understand how human in#uences impact the lithosphere Clarifying Objective EEn.2.2.1: Explain the conse- quences of human activities on the lithosphere (such as mining, deforestation, agriculture, overgrazing, urbanization and land use) past and present AP ENVIRONMENTAL SCIENCE Competency Goal 4: $e learner will build an under- standing of the distribution, ownership, use and degra- dation of renewable and nonrenewable resources. Objective 4.03: Analyze local, regional and global soil aspects. Soil composition and pro!les. Soil characteristics. Soil types. Erosion and conservation Objective 4.06: Analyze land types and uses. Residential and commercial, land use planning. Agricultural and forestry. Recreational and wilderness. Ecotourism, Parks and preserves. AGRICULTURAL EDUCATION ENVIRONMENTAL AND NATURAL RESOURCES E Natural Resources and the Environment Competency EN19.00: Discuss soil erosion and conservation. Objective EN19.01: Explain the causes and e%ects of soil erosion. Objective EN19.02: Describe proper soil conservation practices. 11 Word Wall "roughout the unit on soil erosion, new concepts and ideas will be introduced. Use the space below to help you capture the information by writing de!nitions, drawing examples or creating charts Soil Erosion Transport Turbidity BMP - Best Management Practice In%ltration Subsoil TSS - Total Suspended Solids Sediment Basin PAM - Polyacrylamide Gully Detachment Compaction Soil Texture - Sand - Silt - Clay Turbidimeter Rill Slope (gradient and length) Silt Fence Ba&e Flocculate Deposition pH Rain intensity Sedimentation Check Dams Ditch Coir Soil Structure Wa'le Aggregate Velocity Conservation Tillage Grassed Waterways Mulch Cover Crops Crop Rotation Contour Tillage 12