There have been many definitions of soil quality since the introduction of the term by Warkentin and Fletcher (1977). Two of the most concise definitions of soil quality are:
"Fitness for use" (Larson and Pierce, 1991) and "the capacity of a soil to function” (Karlen et al., 1997). Taken together, these two definitions means that soil quality is the ability of the soil to perform the functions necessary for its intended use.
Probably the most comprehensive definition of soil quality to date was published by the Soil Science Society of America's Ad Hoc Committee on Soil Quality (S-581) as "the capacity of a specific kind of soil to function, within natural or managed ecosystem boundaries, to sustain plant and animal productivity, maintain or enhance water and air quality, and support human health and habitation" (Karlen et al., 1997).
More definitions can be found in the book, "Defining Soil Quality for a Sustainable Environment" (Doran et al., 1994).
Doran, J.W., D.C. Coleman, D.F. Bezdicek, and B.A. Stewart. 1994. Defining Soil Quality for a Sustainable Environment. SSSA Spec. Publ. No. 35, Soil Sci. Soc. Am., Inc. and Am. Soc. Agron., Inc., Madison, WI.
Karlen, D.L., M.J. Mausbach, J.W. Doran, R.G. Cline, R.F. Harris, and G.E. Schuman. 1997. Soil quality: A concept, definition, and framework for evaluation. Soil Sci. Soc. Am. J. 61:4-10.
Larson, W.E., and F.J. Pierce. 1991. Conservation and enhancement of soil quality. In: J. Dumanski, E. Pushparajah, M. Latham, and R. Myers, eds. Evaluation for Sustainable Land Management in the Developing World. Vol. 2: Technical Papers. Proc. Int. Workshop., Chiang Rai, Thailand. 15-21 Sept. 1991. Int. Board for Soil Res. and Management, Bangkok, Thailand.
Warkentin, B.P. and H.F. Fletcher. 1977. Soil quality for intensive agriculture. Proc. Int. Sem. on Soil Environ. and Fert. Manage. in Intensive Agric. Soc. Sci. Soil and Manure, Natl. Inst. of Agric. Sci., Tokyo.