BEsT MANAGEMENT PRACTICEs HANDbooK - Tahoe BMP

5.2.1 SOIL RESTORATIONTopsoil develops over many years and contains organisms and organic matterthat are difficult to replace. Salvaging top soil before grading or soil disturbancepreserves soil material with stable soil structure, organic matter, beneficial soilmicroorganisms, and native seeds. Retaining and reapplying topsoil improvesthe soil’s ability to sustain itself, support healthy vegetation, and resist theerosive forces of wind and water.Figure 5-a: Soil HorizonsMycorrhizal FungiThis mutually beneficialrelationship between plantroots and fungi is significantfor plants growing in poorsoils. Fungi act as an extensionof the plant root, substantiallyincreasing surface area, andextracts nutrients from mineralparticles making them availableto plants. In turn, fungi receivedirect access to carbohydratesfrom their host plants. 3Soil is made up of distinct layers or horizons revealed through a vertical cross-sectionknown as the soil profile. Each soil horizon is the result of a number of geological,chemical, and biological processes that have been taking place for over many years and areidentified on the basis of physical features, such as color, texture, and particle size. Soilcomposition ranges from the O horizon at the top, which contains the most organicmatter, down to the C layer, or bedrock.TRPA BMP HandbookCHAPTER 5: Soil and Vegetation Management2012 Page 5-3