Want to eat "Martian rice", how to transform the farm?

Recently, the color version of China's first Mars exploration global image map was officially released, which will provide a better quality basic map for the Mars exploration project and Mars scientific research. As the planet in the solar system that is most similar to the Earth's environment, the Mars image map will also provide a reference for studying the evolution of the Earth.

In addition to the scientific significance, many people dream of building a new home on Mars. The imaginative "Mars immigration" plan is often mentioned. However, if the food problem cannot be solved, this idea cannot be truly realized. At present, Mars is still a "wild land". What will we eat and drink after "settling" on Mars? Can we really grow potatoes on Mars as depicted in the movie "The Martian"?

Mars soil is not conducive to growing crops

Mars is the first choice for human space migration because it is in the habitable zone of the solar system and is the closest planet to Earth. Mars also has four seasons, a day of 24 hours and 37 minutes, and almost the same day and night cycle as Earth. A year is about 686 days, and the sun on Mars also rises in the east and sets in the west.

Although it is very similar to the Earth, the atmosphere of Mars is very thin, the temperature difference between day and night is too large, the oxygen content is extremely low, the carbon dioxide content is relatively high, and the gravity of Mars is about one-third of that of the Earth.

"From the above conditions, we can infer that humans can walk briskly on Mars with oxygen bottles, and plants can grow upright in an environmentally controlled greenhouse on Mars, using carbon dioxide for photosynthesis and thriving," explained Zheng Huiqiong, a researcher at the Center for Excellence in Molecular Plant Sciences of the Chinese Academy of Sciences.

However, what is the condition of the Martian soil? Can it ensure the rooting of plants and the growth of crops? From some studies, we know that the iron content of Martian soil is extremely high, mainly in the form of iron oxide; the sulfur content is also high, about 100 times that of the earth, which can easily poison plants; the potassium content is relatively low, one-fifth of that of the earth; and there is no organic matter on Mars.

"There are more than 70 chemical elements in plants on Earth, and 35 main components. More than half of them are found in Martian soil, but the content of chemical elements is very different from that in Earth soil." Zheng Huiqiong said that the overall environmental conditions on Mars are much worse than those on Earth.

At present, humans cannot live on Mars for a long time. One of the important reasons is that the soil on Mars is not conducive to the growth of crops, and it is possible that nothing can be grown.

Build greenhouses to transform Mars farms

Not long ago, planetary scientists shared a surprising discovery at the Lunar and Planetary Science Conference: Martian soil may be able to grow rice. To test whether rice can grow in Martian dirt, scientists simulated Martian soil simulants and planted genetically modified rice varieties on them. Even when a small amount of perchlorate (a toxic chemical found on the surface of Mars) was added to the artificial Martian soil, the rice was able to germinate.

Is it not long before humans can eat Martian rice?

"It's still a long way off." Zheng Huiqiong further explained that Mars is very large and may have different soil compositions in different regions, just like Earth. The most notable feature of Martian soil is that the content of iron, sulfur, and perchlorate is very high, so it is definitely not possible to grow Earth plants, including rice, directly. In addition, the atmosphere and water content of Mars are thin, so plants cannot survive in such an environment.

Based on the above reasons, Zheng Huiqiong simulated the construction plan of the Mars farm for reporters.

The first step is to select a location for the farm. "We need to choose a place with sufficient sunlight and low radiation, preferably one with thin soil and easy access to groundwater." Zheng Huiqiong said that although the water on the surface of Mars cannot be used directly, it can be used after purification and transformation.

The second step is to send unmanned probes to conduct on-site investigations after the site selection is completed to detect and analyze the climate, soil, sunlight and other environmental conditions of the site.

The third step is the emergence of labor. In Zheng Huiqiong's view, humans must first land on Mars, formulate a plan for building a Martian farm, and start the first phase of building a closed greenhouse, installing solar energy acquisition devices, and transforming the Martian environment.

After the first stage is completed, Martian agriculture will officially begin.

"We need to launch two 'Noah's Arks' to Mars." Zheng Huiqiong said that the first one will carry the algae "pioneer plants" and probiotic microorganisms with strong stress resistance to Mars for planting, and then supplemented with certain soil conditioners; the second one can transport some high-yield, high-quality, delicious, stress-resistant and storable crop varieties to Mars.

In the greenhouse environment built by humans on Mars, these crops will gradually gain genetic and developmental adaptability and continuous optimization, and eventually produce food that is indispensable to the inhabitants of Mars.