Geologists simulate soil conditions to help grow plants on Mars

Date:
October 27, 2020
Source:
University of Georgia
Summary:
Humankind's next giant step may be onto Mars. But before those
missions can begin, scientists need to make scores of breakthrough
advances, including learning how to grow crops on the red planet.



FULL STORY ========================================================================== Humankind's next giant step may be onto Mars. But before those missions
can begin, scientists need to make scores of breakthrough advances,
including learning how to grow crops on the red planet.


========================================================================== Practically speaking, astronauts cannot haul an endless supply of topsoil through space. So University of Georgia geologists are figuring out how
best to use the materials already on the planet's surface.

To do that, they developed artificial soil mixtures that mimic materials
found on Mars. In a new study published in the journal Icarus, the
researchers evaluated the artificial soils to determine just how fertile Martian soil could be.

"We want to simulate certain characteristics of materials you could
easily get on Mars' surface," said Laura Fackrell, UGA geology doctoral candidate and lead author on the study. Simulating the mineral makeup
or salt content of these Martian mixtures can tell us a lot about the
potential fertility of the soil.

Things like nutrients, salinity, pH are part of what make a soil fertile
and understanding where Mars' soils are at in that spectrum is key to
knowing if they are viable and if not, are there feasible solutions
that can be used to make them viable." In the last decade, Martian
surface exploration has expanded the understanding of the chemistry of
the planet's surface. Using data taken from NASA's surface samples,
the team studied regolith, or the loose material near the surface,
to develop the simulants.

The materials used mimic mixtures of soil, clay minerals, salts and other materials obtainable from Mars' surface by scooping loose material or
mining it from bedrock.



========================================================================== Despite its thin atmosphere, extreme cold and low oxygen, Mars' surface
is known to contain the majority of plant essential nutrients, including nitrogen, phosphorus and potassium.

The presence of nutrients accomplishes one of the big hurdles, but there
are still more challenges. "One problem is, their presence doesn't mean
they are accessible to plants," Fackrell said. "If you actually put a
plant in the ground -- just because the iron or the magnesium is there
doesn't mean the plant can actually pull it out of the soil." Plus,
the nutrients may or may not be present in sufficient quantity or they
may be so high in concentration that they are toxic to plants.

Using simulated Martian soils, Fackrell and fellow researchers have
found the textures of artificial simulants to be crusty and dried which
may reflect some unexpected conditions of Mars soils that make them more difficult to use.

These challenges add up to a very difficult, though not impossible task.

Looking to agricultural science, the group, which includes UGA faculty
members Paul Schroeder, Mussie Habteselassie and Aaron Thompson, adapts solutions used on Earth, recommendations that range from rinsing the
soil to adding inoculants like bacteria or other fungi to the soil to
help the plants grow.

"Specific types of bacteria and fungi are known to be beneficial for
plants, and may be able to support them under stress conditions like we
see on Mars," said Fackrell, who began her studies in geomicrobiology
with Schroeder while conducting her master's thesis research on extreme environments faced by microbes living in hot springs in the Kamchatka Peninsula, in the Russian Far East.

The scientists also see implications from their research for potential innovations in agricultural research for Earth. "Anything we learn about farming on Mars could help with farming in challenging environments on
Earth that help us build to a sustainable future," Fackrell said.

Whatever the eventual solution, the prospect of a manned mission to Mars
hinges on the ability to grow food.

"There are multiple ways you can look at it, but one option might be to
use what's already there as a potting medium, and figure out if that's a
viable way to do it or if you have to bring all the plant materials with
you," Fackrell said. "The question of whether we can use Mars soil to
provide that food will go a long way toward determining the feasibility
of manned missions."

========================================================================== Story Source: Materials provided by University_of_Georgia. Original
written by Alan Flurry.

Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Laura E. Fackrell, Paul A. Schroeder, Aaron Thompson, Karen
Stockstill-
Cahill, Charles A. Hibbitts. Development of Martian regolith
and bedrock simulants: Potential and limitations of Martian
regolith as an in-situ resource. Icarus, 2021; 354: 114055 DOI:
10.1016/j.icarus.2020.114055 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/10/201027105405.htm

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