When we consider space colonization, some of the complications we’ll face are food production, oxygen production and waste filtration. We could spend years of research and vast sums of money creating systems to do this, or carry foodstuffs from Earth, but why do that when it seems we could just plant crops to do it for us? Studies on the Martian terrain suggest that farming is a real possibility. Of course, there are a lot of things we still don’t know yet about agriculture in the extraterrestrial biosphere.
One of the things we need to study more is the importance of the low gravity environment on water and nutrient flow. As long as we can get nutrition and water to the plant roots, the plants can take care of absorbing what they need – but we do have to figure out how to get them there. Obviously, water doesn’t flow as quickly in a low gravity situation, and the same will go for nutrients, in the form of dry or wet fertilizers. If the movement of nutrients towards the roots is too slow, it can actually suffocate the plants. But scientists doing computer simulation comparisons of plants in both the Mars and the Earth gravity-root processes have seen that the slower movement of water and nutrients in this case may be advantageous for the Martian-grown crops. The slow movement helps keep water from dissipating in the soil and being lost.
That also helps with nitrogen retention; nitrogen is an important nutrient for plant life. Mars’ gravity has about one-third the force of Earth’s, and the simulations show that Martian greenhouses would need only about 10% of the water used in their Earth-bound counterparts. The same goes for the nitrogen – much less was needed. Since the soil wouldn’t be leeching out the nutrients, there would be minimal loss and more would actually get used by the plants. The simulation showed that beneficial bacteria in the soil would also thrive on the extra nutrition, and could increase their density by five to ten times normal. Engineers from the University of Florida agree that the nitrogen savings could be one of the most valuable aspects. Mars has a topsoil that is very low in nitrogen, which is vital for plant growth, so fertilizer would need to be brought from Earth.
The benefit to the soil microbes would also be invaluable. However, they also warn restraint, believing that real water usage would end up being more than the estimated 10% figure. There’s also more influencing water movement through the plant than gravity. With low gravity and low air pressure, the water movement through the plant itself may actually be faster. But the studies still have fascinating ramifications and are necessary if we ever hope to colonise the red planet. According to NASA scientists, most researches in extraterrestrial farming have worked with hydroponics or artificial soils. This simplifies testing and allows for both water and nutrient recycling. But using real soil may have advantages like better decomposition of waste.
Many more studies and simulations are in the works, including the role of other plant nutrients such as potassium and iron in low gravity. Of course, the crowning moment will be tests done on the Mars surface, but unfortunately NASA’s budgetary issues have slowed down the research they are doing. But other programs are now stepping in: The European Space Agency has said that they intend to put people on Mars by the middle of this century. Scientists are also looking for funding from private sources to hopefully keep this dream alive.
Image courtesy of NASA
Jenny is an engineer working for root crop harvesting specialists RJ Herbert Engineering. She love the idea of extra-terrestrial farming and the challenges it brings, but until then she will continue to help people make the most of the farms on this planet.