Future astronauts arriving on Mars could farm on land to avoid relying solely on resupply missions and produce a greater amount and variety of food than hydroponics alone. However, new laboratory experiments suggest that growing food on the Red Planet will be much more complicated than just putting in the seed and composting it.
A group of scientists from the Colorado School of Mines planted lettuce and some grass on three types of fake soil from Mars. Two were made from materials mined in Hawaii and the Mojave Desert, and are very similar in composition to the soil on the surface of Mars. To further mimic the composition of Martian soil, the third batch was created from scratch using volcanic rock, clays, salts and other chemical ingredients that NASA’s Curiosity rover has seen on its visits to the Red Planet.
Plants on Mars
Well, both lettuce and grass survived in the natural Mars-like soils, but neither could grow in the synthetic soil, so the idea of growing other foods on future colonization missions becomes increasingly difficult. And it’s not just planting and fertilizing, the soil on Earth is full of microbes and other organic matter that helps plants grow, but the soil on Mars is basically crushed rock.
Other researchers, this time from the Florida Institute of Technology in Melbourne, planted small species of moss in imitation Mars soil under controlled lighting and temperature indoors, just as astronauts would. This time the plants germinated without any problem at 22 degrees Celsius and around 70% humidity.
The seeds of both species grew by being fertilized with a cocktail of nitrogen, potassium, calcium and other nutrients. No seed of either species could germinate in the synthetic soil, so the scientists’ plan is to take nutrients from Earth so they can start farming on Mars.
Scientists think the problem with the synthetic soil on Mars is its high pH, around 9.5. The two natural soils had pH levels around 7. When the researchers treated the synthetic soil with sulfuric acid to lower the pH to 7.2, the transplanted plants survived a week longer than the others, although they eventually died.
The team also faced another problem: the original synthetic earth compound did not include calcium perchlorate, a toxic salt that makes up about 2% of the Martian surface. Perchlorate is a major problem for agriculture on Mars, but it may not be necessary to use calcium perchlorate if plants are well nourished. There are bacteria on Earth that feed on perchlorates, but there would be no organisms on Mars to disrupt plant growth.
REFERENCES:
Colorado School of Mines / Florida Institute of Technology.
