Mycorrhizal Fungi Could Enable Agriculture on the Moon and Mars
- Gauri Khanna
- 11 hours ago
- 3 min read
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Scientists are testing how arbuscular mycorrhizae could help crops grow in lunar and Martian regolith when combined with nitrogen fertilisers
Corn plants grown in lunar simulant with mycorrhizal fungi produced larger biomass and higher chlorophyll levels than plants grown with fertiliser alone, regardless of nitrogen source
A single corn plant survived in Martian simulant amended with processed human waste and fungi, achieving the highest chlorophyll levels and biomass production across all experimental conditions
The Challenge of Extraterrestrial Agriculture
Future human settlements on the Moon and Mars face a fundamental problem: the loose surface material covering these bodies, called regolith, lacks essential nutrients for plant growth. Lunar regolith contains almost no carbon or nitrogen, whilst the phosphorus present exists in forms plants cannot readily use. Transporting terrestrial soil proves prohibitively expensive given launch costs, making in-situ resource utilisation essential for long-term habitation.
Plants require 17 specific elements to survive. Carbon, hydrogen, and oxygen form cellulose for cell walls. Nitrogen enables leaf development. Phosphorus stimulates root growth. Yet planetary regoliths fall short on multiple fronts. Steve Elardo, a planetary geochemist at the University of Florida, notes that avoiding terrestrial soil transport offers substantial advantages, as mass represents extreme expense in space missions. Transporting microorganisms, conversely, adds minimal weight.
Fungal Networks as Biological Infrastructure
Research presented at the American Geophysical Union's Annual Meeting 2025 by Northern Arizona University doctoral candidate Laura Lee explores how arbuscular mycorrhizae could address these limitations. These microscopic fungal networks form symbiotic relationships with plant roots, essentially extending the root zone and providing structural stability akin to glue in terrestrial soils.
The partnership operates through resource exchange: plants supply carbon to fungi, whilst fungi transfer water and nutrients, particularly phosphorus, to plants. This relationship proves especially valuable in nutrient-poor environments like planetary regoliths.
Lee conducted experiments using simulants (synthetic imitations of extraterrestrial regolith) from Space Resource Technologies, testing both lunar highlands and Martian surface approximations. Because simulants lack nitrogen, she introduced this element through two sources: conventional urea-based fertiliser and Milorganite, a nitrogen-rich biosolid derived from processing human waste in Milwaukee, Wisconsin. The latter mimics a resource future astronauts will inevitably produce without adding payload mass.
Experimental Results Show Promise
In lunar simulant trials, plants grown with mycorrhizal fungi consistently outperformed those receiving only fertiliser, producing larger biomass regardless of nitrogen source. Plants cultivated with fungi and Milorganite exhibited elevated chlorophyll levels, indicators of healthier photosynthetic capacity.
Martian conditions proved more challenging. Without fungi, no plants survived in Martian simulant amended with Milorganite. However, one specimen grown with both Milorganite and arbuscular mycorrhizae survived the 15-week experimental period, producing the highest chlorophyll levels and greatest biomass across all lunar and Martian trials.
These findings suggest mycorrhizal networks provide critical support beyond simple nutrient transfer, potentially helping plants cope with the toxic compounds and sharp, shard-like grains characteristic of authentic regolith. A 2022 study by Elardo's team demonstrated that whilst plants could grow in genuine Apollo mission samples, they exhibited stress responses absent in simulant-grown specimens: indicating simulants inadequately replicate regolith chemistry and physical properties.
Ethical Considerations and Future Directions
Lee acknowledges substantial ethical questions surrounding microbial introduction to extraterrestrial environments. However, astronauts will inevitably transport microorganisms through their own microbiomes. Additionally, 96 bags of human waste already remain on the lunar surface from Apollo missions, establishing precedent for biological material presence.
The research suggests that combining mycorrhizal fungi with treated astronaut waste could provide sufficient biological scaffolding for crop cultivation in planetary regolith, offering a pathway toward sustainable extraterrestrial agriculture without excessive Earth-sourced inputs.