Plants May Be Able to Grow in Martian Soil
If we ever want to colonize the Moon or Mars, we're going to need to eat. But an act on Earth as easy as heading to a Wendy's drive-thru is decidedly more complicated in an extraterrestrial environment. Neither locale has an atmosphere openly hospitable to growing food, and any long-term human presence cannot be reliably sustained on a lifeline of deliveries from Earth. The simple fact is that we'll have to find a way to grow food on Mars or the Moon. To that end, a new, preliminary study published in PLoS ONE bears some good news.
Researchers from the Netherlands planted fourteen different plant species in simulated Martian and lunar soils. They found that plants were able to germinate and grow without the addition of any nutrients.
For the experiment, the researchers obtained the same simulated Martian and lunar soils used by NASA. Control soil from Earth, taken from a nutrient poor area near the Rhine River, was also used. Soils were placed in various pots, and seeds from species like field mustard, red fescue, common vetch, tomato, rye, and carrot were planted individually in each pot. In all, there were 840 pots: 3 soils x 14 plant species x 20 replicas for each. All of the pots were kept in the same greenhouse under identical conditions: roughly 60 degrees Fahrenheit with approximately 16 hours of light per day. Only demineralized water was provided.
The research team concluded the experiment after fifty days. Roughly 20% the plants in lunar soil, 50% of the plants in Earth soil, and 65% of the plants in Martian soil were still alive. Overall, crop species were the most successful. 80% of the tomato, rye, carrot, and garden cress plants were alive in Martian soil at the end of the study. Many also produced leaves and a few even grew flowers.
Lunar soil apparently lagged behind the other two soils because of its low acidity and inability to hold water.
The results support an intriguing possibility. Instead of bringing along soil from Earth and maintaining crops within botanical chambers, astronauts could simply erect a dome over an area of the Martian landscape and sow crops within that artificial environment, potentially needing only to apply water and fertilizer.
However, heavy metals are more prevalent in extraterrestrial soils, and they may kill off plants before they can mature, or render the food they produce dangerous for human consumption.
Overall, there are still many, many questions that need to be answered, the researchers say.
"More research is needed about the representativeness of the simulants, water holding capacity and other physical characteristics of the soils, whether our results extend to growing plants in full soil, the availability of reactive nitrogen on Mars and moon combined with the addition of nutrients and creating a balanced nutrient availability, and the influence of gravity, light and other conditions."
Source: Wamelink GWW, Frissel JY, Krijnen WHJ, Verwoert MR, Goedhart PW (2014) Can Plants Grow on Mars and the Moon: A Growth Experiment on Mars and Moon Soil Simulants. PLoS ONE 9(8): e103138. doi:10.1371/journal.pone.0103138