Explain four different ways to protect against soil degradation?
Crop rotation, contour farming, terracing, and shelter belt.
Crop rotation is a huge benefit when fighting against soil degradation. Annually or so, the crop on one patch of land is rotated, so one year is wheat, the next soybeans, etc. The diversity of plants help to maintain soil quality.
Contour farming is also a great way to battle soil degradation. This is pretty much plowing ridges in the soil to prevent run-off of water and nutrients, etc to minimize soil erosion.
Terracing is most commonly seen in rice fields. And since rice needs lots of water, terracing, or forming of stair-like steps will minimize the water loss in fields, and will maintain soil and prevent erosion.
Finally, the shelter belt is also a great way to maintain soil health. In fields, trees are planted in a line or a belt, to block the wind to prevent top soil being blown away.