Uber Eats deliveries to Mars are going to be expensive, so the first colonists of the Red Planet will need to figure out how to grow their own food locally. A new study has shown that dosing plants with symbiotic bacteria can drastically improve their growth in barren Mars-like soil.
Extremely dry and dusty, the rocky dirt that gives the Red Planet its characteristic tinge is terrible for farming. The regolith, as it’s known, lacks the usual organic matter from plants and animals that provide nutrients for crops, meaning attempts to grow things in this dirt alone have left scientists hungry.
But with a little help it can be made workable. Previous studies have shown that adding things like grass clippings, manure and worms can drastically improve Martian soil and help plants grow. Now, another missing piece of the puzzle has been added, with promising results.
Nitrogen is more or less the most important nutrient for plants, so the absence of nitrogen-containing molecules in Mars regolith is a major blow. For the new study, researchers at Colorado State University set out to add it back in, by way of soil bacteria that fix nitrogen from the air.
The team grew clover in samples of a simulated Martian soil, with some of the plants paired with a nitrogen-fixing bacteria called Sinorhizobium meliloti. And sure enough, those plants with the symbiotic microbe grew far better, exhibiting 75 percent more root and shoot growth than clover in the regolith alone.
Interestingly though, levels of nitrogen-containing molecules didn’t increase in the soil around the treated plants. If it had’ve, that might have been a useful way to improve the regolith over time, making it increasingly better suited to growing crops. Still, the results do suggest that these key microbes could be an important ingredient for future Martian farmers.
“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,” say the authors. “This work increases our understanding of how plant and microbe interactions will help aid efforts to terraform regolith on Mars.”
Crops grow better in Mars soil when given good bacteria, study finds [New Atlas]