I am not sure I understand the exact situation. However here are some options for saving the soil there.
You can turn the sloping hill into stair steps with retaining walls to slow runoff and prevent erosion. You can also plant grasses either in bands across the slope or as a solid planting. Grasses are great in holding soil. Anything else that redirects the runoff water or slows its movement will reduce erosion.
Thanks for the question. Please stop in again soon!
Q&A Library Searching Tips