Use of Native Vegetation and Biostimulants for Controlling Soil Erosion on Steep Terrain

Native grass species are increasingly requested for use on revegetation and restoration projects following land disturbance. Native species can be slow to establish, a problem when the goals are to obtain quick ground cover to protect against rainfall impact and sheet and rill erosion and to promote root growth to stabilize soil on steep terrain. In addition, disturbed land is subject to invasion by weed species, creating competition with desirable plants for soil nutrients and moisture. Organic soil amendments and soil stabilizers were used on a large restoration project in northwest Oregon to provide soil conditions that would foster a healthy stand of native grasses and forbes (broadleaf plants) while holding the soil in place until plant establishment could occur. Organic soil amendments were prescribed that would improve soil structure, aid nutrient availability, and provide humic acids and bacterial activators. Organic mulch was added to provide the nutrient energy source for soil microorganisms. The amendments were mixed in a slurry and applied in a onestep hydroseeding application during the late fall of 2001. The materials were applied along with the native seed mixture with a mechanically agitated hydroseeding machine and sprayed on the surface in a pressurized spray. The results of the field evaluation were favorable for the ability of the soil to resist water erosion through the initial rainy season and the native species establishment after application.