Microbiology as part of interdisciplinary soil science

The Microbiology Society is undertaking a project entitled A Sustainable Future as part of our 75th Anniversary, which aims to highlight the Sustainable Development Goals (SDGs) to our members and empower them to use their research to evidence and impact the goals. Earlier this year, we put a call out to our members to submit case studies in the following three areas: antimicrobial resistance, soil health and the circular economy.

This case study was written by Professor Paul Hallett, who is Professor of Soil Physics and tutor of the MSc Soil Science programme at the School of Biological Sciences, University of Aberdeen, UK. It focuses on Soil Health; maintaining the health of our soils has gained increasing prominence in recent years. Soils are essential for the global food system and regulate water, carbon and nitrogen cycles but are put under pressure from population growth and climate change.

Over the past 20 years, the most exciting discoveries in soil science have been dominated by microbiologists. New technologies and the interaction between the classic soil biologists and more fundamental microbiologists allowed for previously intangible hypotheses to be tested. This thrust of new activity has changed the landscape of soil science. There are now potentially more soil biologists in the UK than all other subdisciplines of soil science combined. Whilst extremely expensive state-of-the-art technology has been deployed to study soil biology, the accompanying study of other soil properties sometimes lacked rigour.

Addressing grand challenges like soil degradation, food security, biodiversity loss and climate change requires greater interdisciplinarity in soil science. Microbiology will play a key role in this research, but the complexity of soil, its geographic variability and socioeconomic drivers in the way soils are managed need to be considered too. There are a number of excellent examples of interdisciplinarity in soil science that can be drawn on as a guide to enable future interaction.

For decades, strong links have existed between soil microbiologists and chemists studying nutrient cycling and mineral weathering. Soil biogeochemistry has developed as a new sub-discipline. Soil microbiology has also interacted closely with soil physics, with soil biophysics emerging as a niche sub-discipline of growing size and interest. Research institutes played an important role in the development of these interdisciplinary clusters as they employed large enough teams working on large enough projects for a long enough time.

The DFG in Germany developed ‘Priority programmes’ that achieve something similar across university and institute partners. Interdisciplinarity is essential to obtain funding. Examples of soil science projects are “MAD Soil – Microaggregates: formation and turnover of the structural building blocks of soils” and “Rhizosphere Spatiotemporal Organisation - a Key to Rhizosphere Functions”. These projects have common central experiments, are strongly interdisciplinary, and draw on key specialist facilities across Germany.

In the UK, UK Research and Innovation (UKRI) via the Natural Environmental Research Council (NERC) and the Biotechnology and Biological Sciences Research Council (BBSRC) funded the Soil Security Programme. The seven main projects all had some level of interdisciplinarity, but six focused on soil microbiology. Across all projects, there was little consideration of socioeconomic drivers. Most of the projects were thought up and funded independently, limiting cross-over of research activities. By establishing a cluster of projects, the investigators were regularly brought together, so a number of more interdisciplinary projects have emerged. 

UKRI also funded interdisciplinary research involving microbiology, soil science and many other disciplines in the UK: China Critical Zone Observatory (CZO) programme. This established common experiments in five separate CZOs in China. CZOs were first established in 2007 by the US National Science Foundation (NSF), as environmental laboratories exploring processes from the bottom of groundwater to the top of trees. Highly interdisciplinary research linked processes from the weathering of bedrock to form soil, through to the cycling of elements in soil and their interaction with plants and the wider environment. In the research with China, deep cores (down to 200 metres in the Loess Plateau CZO) unravelled fascinating links between microbiology, geochemistry, soil physical properties and human impacts. New discoveries from this CZO network are now being used to develop decision support tools to improve agricultural sustainability, such as through reduced fertiliser use.

There is a strong need and desire for greater interdisciplinary research involving microbiology and soil science. Hurdles include funding mechanisms, but as demonstrated by DFG Priority Programmes and targeted research programmes from UKRI, these are feasible to address. Centralised longer term field experiments are essential to allow investigators from a range of disciplines to explore the same system. Training in classical soil science has dwindled globally, with the generalists of the past replaced by specialists. This has resulted in the loss of important skills and an overarching knowledge of how soils work. Better engagement between disciplines and greater training of specialists in soil science would help bring about more interdisciplinary, cutting-edge and meaningful research.

About the author

Professor Paul Hallett is Professor of Soil Physics and tutor of the MSc Soil Science programme at the School of Biological Sciences, University of Aberdeen, UK. More information about his work is available online.