Is a greenhouse on Mars called… a ‘redhouse?’ While agricultural endeavors on Mars aren’t quite possible yet, scientists have made a discovery that can help us get there.
New research shows that nitrogen-fixing bacteria can help plants grow better in Mars-like soils. This finding, presented in the journal Plos One, by Franklin Harris of Colorado State University and his colleagues, increases the possibility of farming Martian regolith—a necessary achievement if humans are to set up bases on Mars for an extended period of time.
Background: Martian soil
While the colonization of Mars is an increasingly prevalent topic, there are plenty of reasons why it’s still a pipe dream, chief among them is the obvious incompatibility of the planet with our lifestyle as humans. If humans are to survive on Mars, we’d naturally require water and food.
Growing crops on Mars is difficult; the Martian regolith lacks essential plant nutrients and microorganisms, including nitrogen-containing molecules. On Earth, soil bacteria play a crucial role in converting—fixing—atmospheric nitrogen into molecules needed for plant growth.
This research into the performance of plant life on Mars has led scientists to several possibilities, including using hydroponic greenhouses and controlled environmental systems, like in the International Space Station, or even using advanced synthetic biology to engineer whole organisms.
The alternatives for adapting conditions for plant growth require looking to different and non-traditional sources of food, with previous research even suggesting the substitution of food with microbes.
To examine what the introduction of nitrogen-fixing bacteria could do in the field of astroagriculture, the researchers planted clover in man-made regolith that imitated Martian soil. They inoculated some of the plants with the microbe Sinorhizobium meliloti, typically found in clover root nodules.
The experiment showed that the inoculated clover experienced 75% greater roots and shoots growth compared to the uninoculated clover. When researchers tested the soil of the inoculated clover, they found no signs of elevated NH4—a crucial nitrogen-containing molecule for plants—suggesting that the microbes helped the plant more efficiently absorb the nutrient.
This finding implies that while the symbiotic microbes boosted clover growth, they did not produce an excess of nitrogen compounds that other nearby plants could hypothetically use.
“This study shows that nodule forming bacteria Sinorhizobium meliloti has been shown to nodulate in Martian regolith, significantly enhancing growth of clover (Melilotus officinalis) in a greenhouse assay,” the authors write.
“This work increases our understanding of how plant and microbe interactions will help aid efforts to terraform regolith on Mars.”
Outlook: Space Farming on Mars
While this research could potentially alleviate some of the problems posed by the lack of plant nutrients on Mars, there are other hurdles scientists still need to overcome. The Martian regolith isn’t just inadequate for plant growth; it’s also toxic, containing high levels of perchlorate compounds containing chlorine.