The Earth’s Crust

1. The Earth’s Crust Saving the Soil

2. Saving the Soil • There are many new methods being used by farmers to cut down on the amount of soil lost to erosion:

3. For Example: • #1 Planting wind breaks – rows of trees along the edges of fields cuts down on wind erosion.

4. #2 Covering bare soils with straw holds the soil in place…

5. …and protects the soil from being loosened by rain. The rain hits the straw instead of the soil.

6. The hay also adds nutrients to the soil as it decomposes.

7. #3 Creating terraces in hilly areas

8. Without the terraces, the water would run straight downhill taking the soil with it (or worse, causing land slides!)

9. With the terraces, the water is trapped on each step and crops can be grown.

10. Farmers actually raise fish along with their crops. • They let fish grow in their pools and at the end of the season they use nets to catch them. • An added bonus is the fish manure provides fertilizer for the field, saving the farmers fertilizer costs.

11. #4 Plowing across the grains of hills to reduce erosion from rain.

12. If the farmer plows straight up and down hill, like this farmer has, the rain will run like little water slides straight down the hill, taking the soil with it.

13. If the farmer plows across the hill, he makes mini terraces…

14. …which traps the water…

15. …and the water slowly…

16. …and the water slowly… moves

17. …and the water slowly… moves down

18. …and the water slowly… moves down

19. …and the water slowly… moves down the

20. …and the water slowly… moves down the hill

21. …and the water slowly… moves down the hill leaving the soil where it was.

22. #5 Leaving fields fallow – This is when a farmer doesn’t plant a crop in a field to allow the field to recover nutrients.

23. Wild clovers and natural grasses replace many of the nutrients lost while growing crops. • This saves the farmer money because he doesn’t have to pay for as much fertilizer.

24. #6 Rotating Crops – planting a different crop in each field every year. • Different plants use different minerals so it gives the soil a chance to recover.

25. Let’s say a farmer has 4 fields. To rotate his crops, he plants a different crop in each field. #1 Soy Beans (actually adds nitrogen to soil as it grows) #2 Corn (really hard on soil – takes a lot of nutrients out of the ground) #4 Potatoes with clover (Potatoes take nitrogen out of the soil but the clover replaces it) #3 Peas (also a legume which returns nutrients to soil as it grows)

26. If the farmer kept the same plants in the same fields year after year, the corn would end up killing the soil in field #2… #1 Soy Beans (actually adds nitrogen to soil as it grows) #2 Corn (really hard on soil – takes a lot of nutrients out of the ground) #4 Potatoes with clover (Potatoes take nitrogen out of the soil but the clover replaces it) #3 Peas (also a legume which returns nutrients to soil as it grows)

27. …and even though the other fields are putting some nutrients back, they would rob the soil of the exact same nutrients each season which would also be bad. #1 Soy Beans (actually adds nitrogen to soil as it grows) #2 Corn (really hard on soil – takes a lot of nutrients out of the ground) #4 Potatoes with clover (Potatoes take nitrogen out of the soil but the clover replaces it) #3 Peas (also a legume which returns nutrients to soil as it grows)

28. The normal solution to this was to add expensive fertilizers to the fields to replace what was being lost each year. Fertilizer Fertilizer #1 Soy Beans (actually adds nitrogen to soil as it grows) #2 Corn (really hard on soil – takes a lot of nutrients out of the ground) #4 Potatoes with clover (Potatoes take nitrogen out of the soil but the clover replaces it) #3 Peas (also a legume which returns nutrients to soil as it grows) Fertilizer Fertilizer

29. But, if the farmer rotated where his crops were being grown each year… #1 Soy Beans (actually adds nitrogen to soil as it grows) #2 Corn (really hard on soil – takes a lot of nutrients out of the ground) #4 Potatoes with clover (Potatoes take nitrogen out of the soil but the clover replaces it) #3 Peas (also a legume which returns nutrients to soil as it grows)

30. But, if the farmer rotated where his crops were being grown each year… #4 Potatoes with clover (Potatoes take nitrogen out of the soil but the clover replaces it) #1 Soy Beans (actually adds nitrogen to soil as it grows) #3 Peas (also a legume which returns nutrients to soil as it grows) #2 Corn (really hard on soil – takes a lot of nutrients out of the ground)

31. But, if the farmer rotated where his crops were being grown each year… #3 Peas (also a legume which returns nutrients to soil as it grows) #4 Potatoes with clover (Potatoes take nitrogen out of the soil but the clover replaces it) #2 Corn (really hard on soil – takes a lot of nutrients out of the ground) #1 Soy Beans (actually adds nitrogen to soil as it grows)

32. He wouldn’t have to put as much fertilizer down because the plants would be replacing most of the nutrients for him. #2 Corn (really hard on soil – takes a lot of nutrients out of the ground) #3 Peas (also a legume which returns nutrients to soil as it grows) #1 Soy Beans (actually adds nitrogen to soil as it grows) #4 Potatoes with clover (Potatoes take nitrogen out of the soil but the clover replaces it)

33. Keeping one of the fields in the rotation fallow would improve the situation even more. #4 Fallow Field #3 Peas (also a legume which returns nutrients to soil as it grows) #1 Soy Beans (actually adds nitrogen to soil as it grows) #4 Potatoes with clover (Potatoes take nitrogen out of the soil but the clover replaces it)

34. Keeping one of the fields in the rotation fallow would improve the situation even more. #1 Soy Beans (actually adds nitrogen to soil as it grows) #4 Fallow Field #4 Potatoes with clover (Potatoes take nitrogen out of the soil but the clover replaces it) #3 Peas (also a legume which returns nutrients to soil as it grows)

35. This is called Rotating Crops #4 Potatoes with clover (Potatoes take nitrogen out of the soil but the clover replaces it) #1 Soy Beans (actually adds nitrogen to soil as it grows) #4 Fallow Field #3 Peas (also a legume which returns nutrients to soil as it grows)

36. This is called Rotating Crops #3 Peas (also a legume which returns nutrients to soil as it grows) #4 Potatoes with clover (Potatoes take nitrogen out of the soil but the clover replaces it) #4 Fallow Field #1 Soy Beans (actually adds nitrogen to soil as it grows)

37. And it helps prevent erosion by keeping the soil healthy. #3 Peas (also a legume which returns nutrients to soil as it grows) #4 Potatoes with clover (Potatoes take nitrogen out of the soil but the clover replaces it) #4 Fallow Field #1 Soy Beans (actually adds nitrogen to soil as it grows)

38. # 7 No till farming – normally, farmers till or plow their fields two or three times a year exposing the topsoil to erosion each time. Not Good

39. No till farming is much better. It leaves the stalks and roots of the previous crop in the ground (which holds the soil in place) and plants the seeds without digging up the soil. • Also, the old stalks and roots decompose and add nutrients to the soil.

40. Watch this video in your student share folder and answer these three questions: 1. How many tonnes of top soil are lost each year from a an acre of a farmers field?2. How many tonnes are lost from an acre of pastureland?3. What two ways does wheat residue cut down on soil erosion?