Use of Native Plants and Mycorrhizal Fungi for Slope Stabilization and Topsoil Management.

摘要

The authors report the results of several field and greenhouse projects designed to improve understanding of native plants and their association with arbuscular mycorrhizal fungi in a restoration context. At a site near Los Olivos, California, we tested the erosion control benefits of two live mycorrhizal amendments and a sterile control on a filled embankment. We also evaluated whether the responses vary by the method of application. After three years of field data, we find that the native inoculum cultured from a nearby donor site outperformed a commercially available product in reducing soil erosion. We also tested the utility of applying of a commercial mycorrhizal inoculant as specified by the vendor for use in restoring a cut slope lacking topsoil. We find no evidence for such a benefit, and conclude that other soil amendments and restoration practices should be employed when a cut slope restoration is necessary. The authors used an area in San Mateo County, California to investigate some of the biophysical changes that occur when native topsoil is excavated and stockpiled, and to identify whether topsoil can be managed to maintain or improve its viability as a growth medium for native plants while being stockpiled during a construction operation. Our project tracks a general decline in soil quality from excavating and salvaging operations, evident in the loss of soil aggregate stability, increased bulk density, lost soil organic matter, and a sharply reduced nutrient profile. We find that native species can benefit in subtle ways from the application of a cover crop once stockpiled soil has been redisturbed and re-applied for habitat restoration. These benefits would likely accrue over time and a cover cropping regime would need to be implemented with a carefully managed fertilization plan to replace nutrients lost from the initial excavation.