A computer model of the effects of weak Martian gravity on water flow and nutrient dynamics suggests that it should be possible to farm on Mars:
In a July Advances in Space Research study, Maggi and University of California, Berkeley biogeophysicist Céline Pallud simulated both Mars- and Earth-gravity root processes using BIOTOUGHREACT, a well-regarded model of soil nutrient transport and microbe dynamics developed at the Lawrence Berkeley National Laboratory.
The simulation suggests that slower water transport is actually a good thing, preventing water from falling through the soil and being lost, along with the nitrogen it absorbs on the way.
At Mars gravity — about one-third of Earth’s — up to 90 percent less water would be needed than in a terrestrial greenhouse, said the researchers. Much less nitrogen would also be needed.
“You don’t have a leaching of nutrients. The nutrients you put into the soil, remain in the soil. You don’t lose them,” said Maggi. The simulated bacteria thrived on all this extra food, reaching densities between five and 10 times the usual.
According to University of Florida agricultural engineer Ray Bucklin, an advisor to the Mars Foundation and author of several NASA reports on Mars greenhouse design, the nitrogen savings could be especially important.
“Mars is nitrogen-depleted,” and any fertilizer would need to come from Earth, he said. “And in terms of the soil microbes, they would be in a pretty beneficial situation.”
Bucklin warned that the real-world water savings would likely be much less than 90 percent. “Water movement through a plant has several other things that influence it besides what happens in the soil,” he said. At low gravity and low atmospheric pressure, “water movement through the plant would be accelerated.”
(Hat tip to Aretae.)