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‘Citation Classic’ commentary published in leading soil science journal

06 Feb 2018

Every year or so, the leading soil science journal ‘Soil Biology and Biochemistry’ identifies a historic paper published in the journal as a ‘Citation Classic’, invites the author of the Classic to write a commentary on it, and publishes another commentary alongside it by the Chief Editor that profiles both the subject area of the Classic and the authors of it. A paper published in this journal in 1995 by Professor David Wardle, and his New Zealand colleague Dr. Anwar Ghani, which has since garnered 675 citations, has been recognized by the journal as their Citation Classic for this year. Both their Citation Classic commentary, and an accompanying commentary by the journal’s Chief Editor (Professor Richard Burns) were published today in Soil Biology and Biochemistry.

The Classic paper by Wardle and Ghani is focused on microbial bioindicators of soil quality. In the early-mid 1990s, there was considerable interest in developing easily measured soil indicators of ‘soil quality’ and ‘soil sustainability’, including biological indicators. Several microbial indicators were being used widely at the time, often indiscriminately, and these included the microbial ‘metabolic quotient’. This quotient, which measures the respiration of soil microbes relative to their biomass, was proposed as a measure of microbial inefficiency; a higher value of the quotient was taken to mean that the microbial community was functioning poorly and that the soil therefore was less sustainable and functioning in an inferior manner.

The paper by Wardle and Ghani in 1995 critiqued that line of thinking, by showing through data from soil samples collected along large environmental gradients as well as through reanalysis of previously published data sets and the application of ecological theory, that simple unidimensional indicators such as the metabolic quotient are unable to discriminate among very different sorts of ecosystems, and that no single-dimensional variable can adequately inform on soil quality or sustainability because these are the products of multivariate interactions. Studies such as Wardle and Ghani helped steer subsequent researchers away from single univariate bioindicators to focus on finding more realistic, multivariate bioindicators of soil quality and sustainability.

The 1995 Citation Classic can be found here:

The Commentary about the Classic by the authors can be found here:

The Commentary by the journal’s Chief Editor about the Classic can be found here: