Aggregates vs pores? A survey among soil scientists about perspectives on soil structure

Two perspectives on soil structure have often been juxtaposed in the past: the “solid phase” or “aggregate” perspective and the “pore” perspective. The debate intensified recently with several opinion papers, letters to the editor, and editorials being published on that matter. The discussion centred around the usefulness of the aggregate concept. Main disputed aspects were whether aggregates (a) are suitable experimental units for measuring and upscaling soil functions and (b) exist in situ or are mere artefacts of the separation method. Some researchers view the pore perspective as superior regarding the explanation and measurement of soil functions and predict that it will largely replace the aggregate perspective. This would mean a major change in the mental models that, up to now, many soil scientists have of the soils they study. Yet the topic remains highly controversial. Despite disagreements between researchers following one or the other perspective, some researchers view these perspectives as complementary, not exclusive. Do we not even agree to disagree? Moreover, people taking the same broad perspective may not agree on all aspects on how to use the concept, as the discussion about aggregates as “biogeochemical reactors” for greenhouse gas production showed.

In order to have a constructive and efficient debate, it seems necessary that we better understand the different perspectives, arguments, and use of terms. Moreover, the discussion in written publications only reflects the views of a part of the scientific community. Thus, in order to gain a broader overview of the views currently present in soil science, other – additional – ways of communication are necessary.

An online survey is a low-inhibition tool to get insight into peoples’ thoughts. A short English-language survey will be spread via email and social media with the aim to answer the following questions:

1. How is the approval of pore or aggregate perspective distributed among soil scientists?

2. How do soil scientists judge the compatibility of the two approaches?

3. (How) do perspectives on soil structure differ between soil scientists at different career stages?

Preliminary results of single or multiple choice questions will be presented to sketch the status quo of how the soil science community conceptually relates to soil structure. Data grouped by career stage might give hints for a future development of this debate.