The ‘soil health’ metaphor : illuminating or illusory?

Abstract

‘Soil health’ has become a dominant, pervasive phrase in soil and environmental sciences. But despite its ubiquity, the concept remains elusively ambiguous, largely because ‘health’ here is a metaphor, not a literal scientific construct. So we ask: can this imagery nevertheless still advance research toward stewardship of soils globally? To address this question, we here define soil health as: ‘the vitality of a soil in sustaining the socio-ecological functions of its enfolding land.’ By this definition, soil health reflects not the composition of soil per se, rather its capacity to promote the pertinent functions of the land in which it is embedded. This means that the term has little meaning for a soil divorced from its ecosystem, and that properties conferring such health depend on place and time. From this view, we consider the metaphor's strengths and pitfalls for stewarding soils, and proffer some ways to elevate its use, mostly to spur conversation. We propose that the point of pursuing the soil health metaphor is not merely to assign a number to the ‘goodness’ of soil, but to generate understanding of relational mechanisms and thereby lead us to better nurture attributes that catalyze valued functions, now and perpetually. In the end, the continuing usefulness of the soil health metaphor depends, not on whether or not we can finally entrap it numerically, but whether it propels us to greater reverence for soil, deeper insight into its beneficial processes, and wiser ways of managing it. In time, when the health metaphor can no longer carry this prodigious weight, we may seek a worthy successor; a good metaphor produces good science, and good science produces ever better metaphors.