The secret to farming on Mars? A bit of alfalfa

How this common cover crop unlocks the possibility of growing food on Martian soil

This image made available by NASA shows the planet Mars
This image made available by NASA shows the planet Mars. This composite photo was created from over 100 images of Mars taken by Viking orbiters in the 1970s.

Farming on Earth can be challenging enough with intensifying droughts and climate events. But a team of researchers is trying to figure out how to grow food on Mars — and they might have found a way.

Pooja Kasiviswanathan of Iowa State University joined Appetites to share her breakthrough research.

Check out the full conversation by using the audio player above or by reading the transcript below. The transcript has been lightly edited for clarity.

In the simplest terms, can you tell us what you've discovered?

This study indicates that it's possible to grow crops with alfalfa-treated basaltic regolith Martian soil. So basically, we're able to use two simulated Martian conditions and grow crop plants more sustainably and cost effectively upon treatment of those conditions using natural resources.

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What is it about Martian soil that makes it so difficult to sustain plant life?

I would say the main factor is the low-nutrient content found in the basaltic regolith soil. Also, it is quite porous so it has a low water holding capacity. [This] makes it hard to grow any type of plant using just the soil without any nutrient supplementation.

We know that there is water on Mars but tell us the problem with it?

There is some briny water that is found on Mars and yes, it has a high salinity so you can't directly use that high salt water to grow plants.

That's why in this project, we used a cyanobacterium to biodesalinate that high saltwater, and then we also filtered out the biodesalinated water using basalt type rocks which are found on Mars.

What does alfalfa do to Martian-like soil?

Alfalfa on Earth is a common biofertilizer and it's used for a variety of agricultural purposes. So, I tried growing this plant and I was able to grow it to the extent where I could harvest its shoots, then I crushed it to a powder, and I applied that as a biofertilizer to grow crop plants.

So basically, alfalfa can help plant growth because it's a great source of nitrogen, it contains trace amounts of minerals, and it has like naturally occurring growth promoters.

What were you able to grow with this alfalfa-treated soil?

I was able to grow three crop plants in this project, which were turnip, radish and lettuce plants.

What are some potential caveats or limitations that people should keep in mind about growing food on Mars?

Mainly, we wanted to go step by step and test the effects of one variable at a time. So in the future, it's definitely possible to test other Martian conditions, which can also affect plant growth. Also, we need to scale up this project if we were to actually go to Mars.