1. The Earth’s Crust Saving the Soil

4. #2 Covering bare soils with straw to hold 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.

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) #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) #4 Potatoes with clover (Potatoes take nitrogen out of the soil but the clover replaces it)

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) #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) #4 Potatoes with clover (Potatoes take nitrogen out of the soil but the clover replaces it)

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) #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) #4 Potatoes with clover (Potatoes take nitrogen out of the soil but the clover replaces it)

28. The normal solution to this was to add expensive fertilizers to the fields to replace what was being lost each year . #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) #4 Potatoes with clover (Potatoes take nitrogen out of the soil but the clover replaces it) Fertilizer Fertilizer 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) #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) #4 Potatoes with clover (Potatoes take nitrogen out of the soil but the clover replaces it)

30. But, if the farmer rotated where his crops were being grown each year… #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) #4 Potatoes with clover (Potatoes take nitrogen out of the soil but the clover replaces it)

31. But, if the farmer rotated where his crops were being grown each year… #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) #4 Potatoes with clover (Potatoes take nitrogen out of the soil but the clover replaces it)

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

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

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

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

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?