Rethink Soil Benchmarking
Soil does not have a universal benchmark
Soil is often treated as if it can be compared using a single benchmark. In practice, this does not work well. Soil form under very different combinations of climate, landscape, biology and geology. What looks like a healthy or typical soil in one region may be completely different in another, without being better or worse.
This creates a basic challenge for soil science and land management. How do we compare soil fairly across places that is not directly comparable?
A single global benchmark tends to flatten this diversity. It can hide important local differences or force soil into categories that do not reflect how it actually functions in their environment. This is why a different approach is needed.
Why context matters more than universal standards
Instead of trying to define one global “standard soil”, a more useful approach is to define reference soil that are tied to environmental context.
This is where the idea of pedogenons becomes important. Pedogenons group soil based on the environmental conditions under which they form, including climate, terrain, parent material and key soil properties. Rather than describing individual soil in isolation, they describe soil-forming environments.
This allows soil to be understood in relation to what is typical for their setting, rather than being judged against a universal benchmark that may not be meaningful for that location. It enables what can be thought of as apples-to-apples comparison, where soil is compared within similar environmental contexts rather than across fundamentally different systems.
The reality of uneven soil data across the world
Soil information is highly uneven. Some countries have detailed, high-resolution national soil maps built from decades of fieldwork and observation. Others rely mainly on global datasets that are necessarily more generalised.
Both types of data are valuable, but they are not directly comparable. National datasets capture fine-scale variation and local detail. Global datasets provide consistent coverage but simplify complex landscapes.
Pedogenons offer a way to connect these two perspectives because they are built on shared environmental drivers. This makes it possible to translate between national and global soil classification systems in a structured way, rather than forcing direct equivalence between very different datasets.
What happens when we try to connect national and global soil systems
Recent work comparing Australian national and global pedogenon maps shows that, despite differences in scale and detail, both systems capture broadly similar patterns of soil-forming environments. It also shows that these systems can be translated into each other in a meaningful way.
A key insight is that simpler matching approaches often produce clearer and more interpretable results. This is important because the goal is not just technical accuracy, but practical usability.
The broader message is that it is possible to link detailed national soil knowledge with global frameworks without losing the strengths of either.
Conclusion: Why this matters for science, policy and management
The importance of this approach goes beyond mapping. It allows soil comparisons to become more realistic. Instead of assuming all soil should be judged against a universal benchmark, they are assessed relative to similar environmental conditions using pedogenons.
by Wartini Ng
Postdoctoral Research Associate at the University of Sydney
Wartini is a Postdoctoral Research Fellow whose work advances soil security, with a focus on evaluating soil capacity and condition to safeguard soil into the future. Her research integrates advanced data analytics, proximal sensing, and machine learning techniques to improve the prediction of soil properties using large spectral databases. She now applies these approaches with digital soil mapping, strengthening the assessment of soil capacity and condition as a foundation for long-term soil security.
