The Future of Sustainable Farming Could Be Cold Plasma

IRA FLATOW: This is Science Friday. I’m Ira Flatow. What do the sun, fluorescent light bulbs, and the northern lights all have in common? They’re all made of or give off plasma.

Plasma is a fascinating medium. It’s considered the fourth state of matter, alongside solid, liquid, and gas. And it is everywhere. Experts say that more than 99.9% of all matter in the universe is in plasma form. Now, you may be most familiar with plasma as the stuff inside those glowing novelty lamps you can find at a museum gift shop.

But plasma is being used in a lot of places, including agriculture. Cold plasma, specifically, is being tested as a way to speed up plant growth and make fertilizer that’s better for the environment. And since plasma is everywhere, using it could be a sustainable solution for the future of farming.

Joining me today to talk about this is my guest Dr. Jose Lopez, professor of physics at Seton Hall University in South Orange, New Jersey. He’s also program manager for plasma physics at the National Science Foundation. Welcome to Science Friday.

JOSE LOPEZ: Thank you, Ira. It’s a pleasure to be with you.

IRA FLATOW: Nice to have you because this is one of my favorite subjects. Let’s start with a definition, please. What is cold plasma? How is it different than, say, hot plasma?

JOSE LOPEZ: So I guess we’ll start from the beginning, Ira. So plasma– yeah, everybody says they’re the fourth state of matter. I always counteract that by saying, no, they’re the first state of matter. So when the universe formed, when the big bang happened, and you started to have the formation of electrons, and then eventually the nucleus and all atoms, that very, very first state of the existence of the universe was the plasma state.

Then you had gas, then you had liquids, and then you had solids. So it’s a fundamental state. And as you’re saying, there’s generally categorized in two types of plasmas. One are hot plasmas, and those tend to be your astrophysical plasmas, your stars.

And then the second type of plasma is what we like to call our cold plasmas. And those type of plasmas, the trick there is my favorite subatomic particle is the electron. You funnel energy into the electron, and then the electron, whatever is in the background there, whatever atoms are in the background there, there are molecules there and ionizes them. It rips off more electrons and it causes a cascading effect, and it creates a plasma.

But the rest of, the majority of the other stuff, the ions, and the neutrals there, are all in cold state. So what that means is you can touch them. A biological organism like us or a plant can touch a cold plasma.

IRA FLATOW: All right, let’s get together about plants. What does cold plasma do when you put it together with plants and agriculture?

JOSE LOPEZ: So this is still an emerging field. I mean, it’s extremely active area right now, to the surprise of many folks. I mean, I’m a plasma physicist as you mentioned. I know about biology. I know about living organisms, but I’m constantly surprised at what plasmas can do.

So one of the interesting things that we’ve seen over the last decade is that when you take one of these cold plasmas that you make out of air or atmospheric gases is that you interact them with plants. And what we’ve seen is that it stimulates the plant to grow better, especially in the early stages of the plant.

So you can treat seeds with these types of plasmas, with these cold plasmas. You can treat them at atmospheric pressure or even in vacuum systems, low pressures like the types of plasmas that are used for semiconductor processes to make microchips. And what we see there is that when those seeds are planted, they grow more robust, the plants. They’re healthier and they grow larger.

And we see the same thing when we keep doing plasma treatments for only a few seconds– I mean, up to a minute or so. And we see that it stimulates the growth of these plants. And what’s happening? That’s what we’re trying to figure out.

IRA FLATOW: So we don’t know what’s happening. We just know that it happens.

JOSE LOPEZ: Yeah. So the fascinating thing about plasmas, as I said, it was that first state of matter. And they expand the scales of the universe from the largest of the largest, the size of the cosmos, all the way down to these type of plasmas– these cold plasmas that you can make in laboratories. And you can make them out of air. And once again, with electrons, with electricity, you can make these types of plasmas.

And what we’re seeing is not entirely clear. I mean, it seems to be that the biochemistry in the plant is stimulated. Some people say that it’s what’s in air. It’s that nitrogen and oxygen that’s in-air that mimics natural reactions that would happen in these plants. And that causes the biochemistry in them to just get going. And the seeds, we believe, it wakes them up from their dormant state, and it just causes them to grow even faster.

IRA FLATOW: Was this noticed in nature before you physicists came along with your ideas about plasma that, hey, something’s going on when the lightning is out or something and my plants are growing better?

JOSE LOPEZ: You’re right, Ira. I mean, there are historical reports. And these aren’t greatly documented, but we have seen in a historical scientific records in locations where lightning bolts hits soil that those were the most fertile places. And kind of it makes sense, because when a lightning bolt happens– it’s not a cold plasma in that case. It’s very much a hot plasma, thermalized plasma.

But it just channels nitrogen, or what we would say, fertilizer into that soil. And we actually are seeing similar effects when we take cold plasmas, especially ones that are made mostly of air. We see that there’s an increase in nitrogen uptake. So in other words, it’s acting like a fertilizer, like ammonia would, for example.

IRA FLATOW: OK, let’s talk about that because we don’t like what fertilizers, common fertilizers, are doing for climate change. Could plasmas be one of the answers for that?

JOSE LOPEZ: Possibly I mean, you look at different reports. But anywhere from 1.5% to 3% of all our electrical power consumption goes into making fertilizer. And that’s just, I mean, just think of the scale of the world and how much power that is.

So with these types of plasmas you can have a localized situation where you can create a fertilizer. I mean, right now, you’re dependent on companies to make this fertilizer and transport it to the farms or the greenhouses. And the possibility could be that, on the local farm, whether in the United States or in India or different countries all over the world in Africa, South America, you can have a possibility of the local farmer taking the air that’s all around and the electricity that’s being delivered to the farm there and creating these plasmas to do a similar reaction, but at atmospheric pressure, and create fertilizer.

IRA FLATOW: Are people actually studying this–

JOSE LOPEZ: Yes.

IRA FLATOW: –and trying this out?

JOSE LOPEZ: Yes.

IRA FLATOW: Give me an idea.

JOSE LOPEZ: So there are folks looking at– and some startup companies coming up about, trying to basically replace the Haber Bosch process. And instead of doing it at an extremely large scale, the current way we make fertilizers, think of huge refineries that you see and in different places like Texas and especially here in New Jersey, and bringing it down to literally a corner of a barn somewhere or a small setup where you can create fertilizer.

IRA FLATOW: Ha, ha. Because we keep seeing more and more of what these indoor vertical gardening situations.

JOSE LOPEZ: Yeah.

IRA FLATOW: Would that be treatable, usable?

JOSE LOPEZ: Yes, absolutely. I mean, I think when we talk about sustainability and especially in growing our food, I mean, we rely now very heavily on these huge fields of land to grow tremendous amounts of food. And then, of course, that food has to be transported into the big cities, right?

And what we’re seeing globally is that there’s a migration of people away from rural areas and into these big cities. So I mean, one possibility of sustainability is growing foods in the cities. I mean, when you walk around different parts of New York City or my hometown of like Newark, New Jersey, you see lots of land that are not being used for anything.

So the possibilities you can do urban food growing, having farms in those locations. And this technology, this type of plasma technology is something that is sustainable. It’s Totally Doable there.

I mean, we have all the ingredients. We have air. We have electricity. It’s perfect. It’s a perfect technology for that movement you’re talking about.

IRA FLATOW: In the lab, what does cold plasma applications on plants look like? Is as easy as waving a magic wand?

JOSE LOPEZ: [CHUCKLES] It kind of does look like a magic wand in a sense. So there’s many ways to kind of do it. Can have what we call volume plasma where you take a large amount of gas, and you put it between a sandwich of two metal electrodes, and then you introduce an electric field. So in other words, you introduce this electricity, and it creates this glow-like formation that effectively what you see inside a fluorescent light bulb. And you can create that.

The other approach is you can create what are called atmospheric plasma jets. And these are basically, as you’re saying, magic wands. The plasma shoots out in a jet-like, almost like a needle-like pencil structure. And then you can treat locally one seed at a time or the body of the plant using this magic wand as you labeled it. I like that. [CHUCKLES]

IRA FLATOW: Wow. I’m just thinking of those globes I talked about where you see the lightning sort of strikes out when you put your finger on the globe.

JOSE LOPEZ: Yes.

IRA FLATOW: That’s plasma. Could I take my own seeds from home? It’s the growing season now. Could I hold them up to that globe and just let it sit there for how long and get treated and try my own experiment?

JOSE LOPEZ: Well, in that case, Ira, the globe is, of course, encasing the plasma. And what you do when you touch the glass, that insulating material there, is the conductivity of the plasma, those tentacles, are attracted to your fingers. And of course, you become a perfect conductor of that.

So in a sense, yes, you can. The only thing there is you’re not getting direct plasma treatment. You’re getting indirect plasma treatment there. But once again, it comes down to those my favorite subatomic particles, those electrons.

Something is happening there, right, that you have that electric field that’s induced in your body or induced in the seed. So interestingly enough, there have been some reports in the literature and colleagues of mine that have done that kind of research. They’ve taken seeds, put them on those plasma balls, and then they’ve planted them.

And they report in the literature that they’ve seen better growth in their implants. So yeah, you might be onto something. That’s an easy way to do it at home.

IRA FLATOW: And I guess because it’s electrical and seeds and plants– they’re electrical– there could be some electrical connection there somehow.

JOSE LOPEZ: Yeah, absolutely. Absolutely. I mean, everything’s electrical, right? I mean, you and I are thinking right now. And those neurons that are shooting your brain is because you have charge moving through our nervous system there.

And it’s the same thing when light comes into your eyes, and it gets refracted by your eye lens there and hits the back of your retina that you have an electrical stimulation that’s happening there. I mean, if you look at stars, Carl Sagan used to say all the time we are star stuff. And that’s absolutely true.

Everything that we’re made out of, carbon and all of those elements on the periodic table, were formed inside a plasma, inside a star that became unstable and blew up as a supernova and created all of this that eventually, of course, formed into the Earth and eventually formed into living organisms like us. So it’s all connected. I mean, we’re just starting to scratch the surface of understanding it.

IRA FLATOW: Very exciting, Dr. Lopez. Thank you for taking time to talk with us today.

JOSE LOPEZ: My pleasure, Ira. Thank you.

IRA FLATOW: Jose Lopez, professor of physics at Seton Hall University in South Orange, New Jersey. He is also program manager for plasma physics at the National Science Foundation.

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