The Big Picture: What is soil erosion?
LEARNING OUTCOMES What: investigate what soil erosion is and why it happens How: watch a video clip to find out about a case study in Kenya that has problems with erosion Why: so that you can understand the effects of soil erosion on farmers
CONNECT: WHAT DO YOU THINK HAS HAPPENED TO THIS LAND? WHY?
ACTIVATE: Match up these key words with their definitions and copy them into your book‌
Wind and water have washed away the top layer of fertile soil. Water is channelled off from a river or stream to supply fields with water. The crops are helped to grow by having a constant supply of water. The water can require electronic pumps to supply the whole area.
Salinisation: Soil erosion / exhaustion: Irrigation:
In dry places where evaporation rates are high, the moisture is absorbed quickly from the top layer of soil. This leads to an increase in salt content in the soil and can make growing crops harder. If the problem continues, the soil may be completely unable to grow crops.
Watch this clip: http://www.youtube.com/watch?v=QT7hklD2l2M Make some notes whilst the video plays. You need to use this information later. You may want to divide your page like this‌ Causes of soil erosion
Effects of soil erosion
Task: Read pages 186-187 about soil erosion. Make your own copy of Figure 3 and add in the labels. Extension: Now rank in order of importance the reasons why soil erodes, from 1 being the most important to 10 being the least important reason.
DEMONSTRATE: Exam Question: Explain the causes and effects of soil erosion (6 marks)
REVIEW: Peer assess your exam questions: Have they explained the causes of soil erosion? Have they explained the effects of soil erosion? Remember, describing is saying what, explaining is saying why. How many marks do you think they have got? 1-2 marks (basic, simple sentences, mostly descriptions) 3-4 marks (some explanation, no details, a bit vague, might have mentioned causes or effects) 5-6 marks (detailed explanation, specific information, explains causes and effects thoroughly)
REFLECT: Think-Pair-Share‌
What solutions are there to problems of soil erosion?
HOMEWORK:
Complete your worksheet about the problems and solutions to soil erosion in rich and poor countries.