Ground cover describes the proportion of the soil surface covered by some type of protective material, which usually includes litter, gravel, rocks, microphytic crusts, in addition to standing plant material. Unprotected bare soil can be determined as
Bare soil = 100% - Ground Cover
References and Further Reading
Society for Range Management. 1989. A glossary of terms used in range management. Society for Range Management, Denver, CO. 3rd ed. p 8.