A Mars soil map now exists at a scale never attempted before. A PhD student at the University of Sydney, Daniel Irving, has produced what the university calls the first comprehensive classification system and map of Martian soils, according to a release dated October 16, 2026. The research, published in the soil science journal Catena, classifies almost 800 million locations on Mars and proposes a new term for Martian soil classes: “areths”, derived from Ares, the Greek name for Mars.
How the Mars soil map is organised
Irving, from the Sydney Institute of Agriculture and the Faculty of Science, used orbital observations and models to sort the planet into a hierarchy. The Provisional Polythetic Areth Classification System, or PPACS, groups Martian soils into 10 major “realms”, 100 “assemblages” and 2,000 detailed “forms”, based on properties including texture, mineralogy, pH and profile thickness. The classification comes with a global map showing where each class occurs.
“Scientists have mapped Mars’ geology, mineralogy and chemistry before, but our system brings together multiple properties into a single framework,” Irving said. His supervisor, Professor Alex McBratney, noted that a future greenhouse would need more than air, water and light: its builders would need to know what lies beneath.
The best candidate for farming
As a proof of concept, the researchers scored all 2,000 soil classes on traits important for plants, including water-holding capacity, pH, profile thickness, clay and gravel content. One class, Nohibareth, scored highest at 0.93 on a zero-to-one scale. Its modelled average profile has a pH of 6.8, 72 percent clay, minimal sand or gravel and an estimated water-holding capacity of 202 millimetres per metre.
The map places it mainly in the mid-latitudes, around Tharsis, central Arabia Terra and Elysium Planitia. Nohibareth covers just 0.14 percent of Mars’ surface. Water-holding capacity was the limiting factor in 73 percent of forms, and classes from the Fareth to Mareth realms all scored below 0.3.
The other side: what the map leaves out
The researchers stress that this does not mean crops could be grown directly in Martian soil. The university says these areas are candidates for closer investigation, not selected greenhouse sites, and future habitats would still need controlled environments, water, nutrients and treatment of potentially harmful substances.
The current map does not include factors such as perchlorate toxicity, nitrogen availability or depth profiles. Many inputs are inferred from orbital data and terrestrial relationships, so the classification will need revision as direct measurements improve. In other words, this Mars soil map is a framework built from remote observations, not from samples dug up and tested.
There are no direct security concerns in the announcement. As for the next steps, the university suggests making or obtaining Mars-like mixtures that represent the mapped classes and testing them on Earth with crops, nutrients and managed water. Rover measurements and samples could later check whether the promising classes are really where the models place them.
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Lessons for Earth
Although Martian soils contain no organic matter, the university says the work may help soil scientists understand difficult landscapes on Earth, such as the Atacama Desert, the Pilbara region and polar regions. “People often think soil needs lots of organic matter to function,” McBratney said, but some arid soils contain very little. Irving added that every rover mission collects valuable information, and scientists need consistent ways to organise and compare it.
My view on this Mars soil map
As a writer, I feel the most useful part is the framework itself. A shared system lets scientists compare places and update the map as data improves, and the “provisional” in its name is an honest signal. The 0.93 score is eye-catching, but a score on a model is not a harvest. I would treat it as a guide for where to look first, and I would wait for the toxicity question, especially perchlorate, to be modelled before reading too much into any single site.
FAQ: Martian soils and “areths”
What is an areth?
It is the new term proposed by the University of Sydney researchers for Martian soil classes, derived from Ares, the Greek name for Mars.
Which Martian soil looks best for plants?
In the study’s proof-of-concept scoring, a class called Nohibareth ranked highest at 0.93. It covers 0.14 percent of the surface and is modelled with a pH of 6.8 and 72 percent clay.
Does this mean we can grow crops on Mars?
No. The researchers say crops could not be grown directly in Martian soil, and the map does not yet model perchlorate toxicity or nitrogen availability. Controlled environments would still be needed.