a soil - amendment product for preparing a damaged or degraded soil ecosystem to establish a self - sustaining floral / vegetative rhizosphere contains a mixture of composted organic biomass , fiber , charcoal , and small amounts of inoculants to promote the growth of beneficial microorganisms including mycorrhizal fungi and nitrogen - fixing bacteria . embodiments also contain a water - holding agent such as a starch - based polymer that is effective to prevent water from flowing downhill or seeping away from the surface . methods of application and other uses for the soil - amendment product are also described and claimed .