Soil erosion occurs when water from rain or runoff picks up particles of soil and carries them away. When water follows the path of least resistance downhill, it can cut deep gullies into soil. Clay soil is more likely to erode into deep gullies because eroded clay particles will take longer to settle. But soil erosion can be controlled by controlling the path of water.
Change the slope of clay soil with a shovel, rototiller and landscaping rake so that there are no steep slopes. Gullies are cut into clay soil when water flows directly downhill. Erosion can be prevented by terracing a slope along the land's contour or grading it so that it drops only 1 foot vertically for every 3 horizontal feet.
Install drainage ditches or culverts in areas of high erosion potential. Drainage ditches carry water away from areas of high erosion potential to deposit them in areas where erosion potential is lower. Line the surface of the ditch or culvert with rocks to prevent erosion of the soil in the culvert or ditch.
Plant vegetation on the sides of hills, including grass and clover. Vegetation such as grass grips soil in its roots and prevents water from carrying it away.
Spread certified weed-free hay or straw over the grass-seeded soil. The straw will help hold soil and seed in place until the grass seed can become established.
Place straw wattles, logs or hay bales along the contour of a slope to prevent erosion. This provides a barrier to runoff during heavy rainstorms. Straw wattles are plastic tubes of netting filled with straw. They may be purchased from an erosion control material supplier. Place the wattles, logs or bales in alternating dashed lines to prevent runoff from running straight downhill. The water will be forced to meander back and forth between the barriers and will slow in velocity. This will reduce the chance that it can pick up clay soil particles.
Place straw bales directly into a gully to create a dam that prevents the gully from growing any larger. You must dig out the gully and partially bury the straw bales. The bales must overlap, like the bricks of a home. Use two rows of interlocking straw bales to form your dam.