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  1. 1. SOIL EROSION<br />By: CathlinAseron, Rachelle Azcarraga and Pauline Tomelden<br />
  2. 2. What is Erosion?<br />– is a gravity driven process that moves solids (sediment, soil, rock and other particles) in the natural environment or their source and deposits them elsewhere.<br />
  3. 3. Causes of Soil Erosion<br />WIND (Wind Erosion)<br /> - Erosion caused by the winds of high velocity that more likely occur in dry areas where soil is loose and unprotected by vegetation. Because of this high velocity of the wind, wind abrasion occurs. This is seen in ventifacts, or rock fragments that have been cut and polished by the sandblasting action of windblown sediments. Loose rock particles that are blown away by the wind can cause deflation. Example of this is the desert pavement. <br />
  4. 4. Causes of Soil Erosion<br />WAVES<br /> - Erosion produced by the waves and currents in the ocean. Large waves pound the shore with tremendous force, producing a hydraulic-lifting action that dislodges large masses of coastal rocks. The blocks fall to the ocean bottom, where they undergo more erosion along with other wave-battered rock debris that has accumulated there. The sand and rock fragments grind each other and scour the shore.<br />
  5. 5. Causes of Soil Erosion<br />WATER<br /> - Steeper slope causes water to flow faster. When water flows rapidly, more soil are carried away.<br /> - Slow moving water carries fine particles. Fast moving water carries stones, and even big rocks. As water flows, big rocks strike other particles. The particles break into smaller pieces and are carried away by water. Water eventually slows down and large particles settle followed by sand. Fine particles are deposited along the way. This is the way by which floods cause erosion.<br />
  6. 6. Causes of Soil Erosion<br />GRAVITY<br /> - When the rock is loosened by weathering it is subject to erosion by gravity. Such erosion may occur slowly and imperceptibly, as soil creeps downhill over a period of years; or it may occur suddenly, as in a dangerous landslide. Down slope movements of rock and soil caused by gravity are knows as “mass wasting”.<br />
  7. 7. Causes of Soil Erosion<br /> - As it moves material from higher elevations to lower elevations where other eroding agents such as streams and glaciers can then pick up the material and move it to even lower elevations. <br /> - Mass-movement processes are always occurring continuously on all slopes; some mass-movement processes act very slowly; others occur very suddenly, often with disastrous results such as landslides.<br />
  8. 8. What can we do to prevent this?<br />Reforestation<br /> – is the planting of trees to replace those that were burnt or cut.<br /> – trees reduce the amount of flowing water. Roots of trees absorb water and hold the soil together. Leaves that fall on the ground holds the soil.<br />Growing grass/ Planting Vegetables<br /> – grass and vegetables help prevent soil erosion.<br /> Grass: it has thick roots that holds the particles of the soil. If there is no grass, wind will carry the topsoil away.<br />
  9. 9. What can we do to prevent this?<br />Contour Plowing and Terracing<br /> Contour Plowing is cultivating along curve lines that go around the hill at a fixed level. Contour Plowing slows down the runoff of soil water from the land.<br /> Terraces keep water from the hillside. The water is absorbed and does not follow directly down hill. It also prevent soil from moving down hill.<br />Planting trees around farmlands<br /> – farmers plant rows of trees(wind breakers) to surround big areas of farmland. These trees protect the farm from the wind that causes soil erosion.<br />
  10. 10. What can we do to prevent this?<br />Strip Cropping<br /> – is the alternate planting of grasses and crops. It prevents the top soil from being blown away by the wind or washed away by rain. Grasses that remain after the crops are harvested hold the soil together.<br />
  11. 11. QUESTIONS!<br />
  12. 12. NUMBER 1<br />Enumerate 3 causes of Soil Erosion and 4 ways that we can prevent Soil Erosion. (It should come from the ones that we discussed)<br /> – Gravity, Water, Waves, Wind<br /> – Reforestation, Planting vegetables/growing grass, Contour Plowing and Terracing, Planting trees around farmlands, Strip Cropping<br />
  13. 13. NUMBER 2<br />What is Strip Cropping?<br /> – It is the alternate planting of grasses and crops. <br />
  14. 14. NUMBAR 3<br />Why can Contour Plowing help prevent Soil Erosion?<br /> – It absorbs water, and it prevents the water from going down hill.<br />
  15. 15. NUMBER 4<br />Define Erosion in your own words.<br /> – It is when the solid particles such as sediments, rocks and other particles in the natural environment are deposited elsewhere.<br />
  16. 16. NUMBER 5<br />Enumerate 2 causes of Soil Erosion, and explain why it is a cause.<br />– Wind: It occurs in dry places where soil is loose and unprotected by vegetation.<br />– Water: Fast moving water can carry small particles and even rocks, that can strike other particles too.<br />– Waves: Large waves can pound the shore making it to break more particles.<br />– Gravity: Mass-wasting – Down slope movements of rock and soil caused by gravity.<br />
  17. 17. NUMBER 6<br />Enumerate 3 ways to prevent Soil Erosion and explain why it is a way to prevent it.<br />– Reforestation, Contour Plowing, Terracing, Strip Cropping, Planting vegetables/Growing grass, Planting trees around farmlands.<br />
  18. 18. NUMBER 7<br />Why is it necessary to plant trees around one’s farmland?<br />– It protects the farm from the wind that causes soil erosion.<br />
  19. 19. NUMBER 8<br />What is the difference between the two causes of Soil Erosion? Waves and Water.<br />– Waves pound shores with tremendous force directly while, fast moving water carry big rocks that strike other particles that break down to smaller particles.<br />
  20. 20. NUMBER 9<br />Why is Gravity a cause of Soil Erosion?<br />– Due to the heaviness of the soil, it can easily be pulled down by gravity.<br />– Change of climate<br />
  21. 21. NUMBER 10<br />Give 3 ways that a student can do to prevent Soil Erosion.<br />– Not picking flowers or plants, plant plants in your garden, promote the importance of preventing soil erosion<br />