Reducing greenhouse gas emissions from agriculture calls for strong collaboration between scientists and farmers to develop trust and implement meaningful changes. Learn more about the innovative practices being undertaken at a rice farm in Arkansas and what that means for the climate!
Transcript
Maoya: Let's start by just talking about measuring methane and working in rice fields in general. Start about telling us how you came to work with flux scientists, and exciting opportunities and maybe risks that you had in mind.
Mark: Thanks to both of you for having me on and thanks for your interest in this field. We are a family farm. My grandfather started growing rice after coming back from World War II in the '40s, and we've been growing rice ever since. My dad and mom are part of the farm, my sister and brother-in-law and nephew and cousin. So, it's a family operation that continues on. We started back before my lifetime, really, focusing on how we could make things more efficient when it comes to water usage and things like that. Through that, sort of built-in to the conservation space and became more focused over the years. And, how do we do better with the land that we have as far as using less water, creating more wildlife habitat, creating new opportunities for reducing greenhouse gases.
Through a lot of that work, one of our key parts of our “personality”, if you will, was collaboration. We were always open to working with multiple researchers and other fields just to learn what's going on out there, just to stay curious about the different things that others were doing and how that impacted the world of food, and how that connected all the way back to the fields through we grew that food in. We have opened our fields up where research can be done and tried to support that as best we could for many years. In the mid-2010s, we became acquainted with Dr. Benjamin Runkle and Dr. Michele Riba, the former who's from University of Arkansas, the latter who's from the Agricultural Research Service, both whom are here in Arkansas, who had a keen interest in measuring in-field methane fluxes. We were coming to understand the methane situation surrounding rice.
Rice is an incredibly important crop. It's 20 percent of the calories in the world. In some countries and some environments, it makes up far more than that. As far as with the daily caloric intake, how we grow rice and how we support the world food system with that certainly matters. Learning to measure and understand how we can minimize the methane impact from that certainly seemed like something that had value. This group had the technology and the expertise to dig into that further. It was just a year or so into that, I think, when Dr. Beatriz was able to join the team as a postdoc and has been part of that ever since. We've really enjoyed the collaboration and the opportunity to host them on the farm. We've learned tons of things through that collaboration.
Maoya: Tell us a bit more about what you're actually doing in the field, what you're measuring, and what's the approach?
Beatriz: Thank you, I'm happy to be here and thank you for the invitation. I'm actually from Spain, and we grow also rice. So, that's why I came into the rice work, because I did my Ph.D. there, studying rice. It also has this cultural food component. You might have heard about the paella in Spain. So, it's really something that is really culturally important in the food culture of the country.
After that, when I finished, I was looking for an international experience to do a postdoc. I found that Arkansas was the first rice producer in the U.S. I also found how here in Arkansas, we have this issue with the aquifer. Aquifer levels are declining because of the water withdrawals. I found this problem about rice, water use, and how [by] implementing new water-saving practices we can decrease water use, but also methane, or greenhouse emissions. So, that's one of the things we will measure in the field. Because rice is continuously flooded, it creates [an] anaerobic (lack of oxygen) environment in the soil that creates methane.
When we do, for example, this technique that we call alternate wetting and drying, the farmer will allow the soil to dry down naturally, not draining the field, for a few days, keep maybe their field muddy, dry, and then flood again. You allow the soil to oxygenate, and then we reduce methane emissions. But at the same time, we are reducing water use. Those are the two main things we study in the field. We track water - we install flow meters in our rice fields. That way we can track the water use, and then we also measure greenhouse gas emissions. We have eddy covariance towers, but those are expensive. So, we cannot have eddy covariance towers in every field. So, we also measure with chambers manually and you need to go close the chamber for one hour, take samples, or less, depending on the method.
So, those are the main measurements we do in the field besides leaf area index, how tall is the plant, different measurements in the soil, water, canopy. We also use other tools or models like decision support tools that help us or estimate greenhouse gas emissions because we cannot have sensors in every field. So, we can model or simulate emissions in fields that we don't have sensors.
Note: Paella is a delicious rice-based meal traditionally cooked in a giant pan with a variety of meats, broth, and saffron for seasoning.
Maoya: Are these experiments in actual production fields? What is it like to, sort of, develop these best management practices?
Mark: The beauty of this project is that it is a field-level research experiment. It's two production fields, actually. The great benefit of that is getting to see what happens in a real-world environment. The downside of that, they're not working in a laboratory. They're working in a real-world environment where there are mosquitoes and snakes, humidity and rain, and all of that type of stuff that has real implications not only on the data, but also on people collecting the data and creates a number of challenges.
What we have is, really, two 70-acre fields that are adjacent to one another. We treat those fields basically the same as far as, we try to plant it on the same day, irrigate it on the same day, fertilize it on the same day, all of that type of stuff. From that point, we will start varying the irrigation practice on that based on what the team of researchers wants us to do that year. I believe we're going into our 10th year of research. So, let's call one field A, one field B. On year one, we probably did AWD, or alternate wetting and drying on field A, and not on field B. Then, the next year, vice versa, do it on B and not on A. In the third year, we did both traditional flooding, and then the fourth year we varied as many permutations of that as you can within those two test fields so that they could set baselines, compare against those. Then, see how the different practices were impacting the methane flux from that across different years, with different weather events, different planning dates, all of that sort of thing.
So, they've developed a large store of data that they were able to take and build these models to understand more and see exactly what the emissions reduction was. These are pretty intensely technological tools that they have out there that are not cheap. It's not as if you can replicate that and put them on fields all over the place. You have to use those to learn what the impacts are based on the different parameters and different variables within that field, and then try to extrapolate from that and create modeling so we can see how that happens in the rest of the world. But it's based on a real field that is real production rice which is harvested, goes into the supply chain, that is used by those out there that are buying and eating rice.
The insight that the tools have provided in the real-world scenario have certainly created the knowledge to help us extend those same practices on other fields and really underscore the fact that some of these practices may be difference.
Maoya: Beatriz, tell us a bit more about what it takes to determine methane reductions or water savings. What does it take to make these conclusions over the years?
Beatriz: Dr. Runkle started having these towers in this summer of 2015. The first paper we got to publish is was three years later. We were able to publish that [by] implementing alternate wetting and drying, we could save 65% methane. We have that in our first paper, but then we have a second paper that the reduction was higher - 80 percent with the towers, the eddy covariance towers. We have also published a paper with 5 years data of chambers, where we also have values around 70 or 80 percent reduction in methane.
This is useful for models and the tools I was mentioning before, for example, the Fieldprint Platform that is by Field to Market. Those tools are ways of modeling. Those models are based on field data. So, we need to generate that field data that is also needed to keep updated because sometimes the studies get outdated. Maybe they were in the 90's, or we need to do more research because there are new cultivars coming, new water-saving practices. Our research keeps the data that will be eventually used in these models that you can apply to other fields, because unfortunately we cannot measure or have towers in every field. We have other fields, but you cannot have towers in all the fields. We only have them at Isbell Farms.
Maoya: In terms of generating numbers, these were impressive numbers. At what point are these meaningful enough to not be a risk to then just scale the practice?
Mark: Anytime there's new activity in agriculture there's an inherent risk that you're changing a practice that you're comfortable with. What this data does help us do is be a little more comfortable with that risk. That risk is still there as far as, when you're doing AWD, if you don't manage to get the water back on quickly enough there's potential damage you can do. But if managed correctly, we saw no yield difference, no yield drag from the practice. It was a win-win - saved a little bit of water, sometimes saved a lot of water, and of course reduced the greenhouse gas emissions.
Let's start with water savings. If you look globally at rice production, and you convert it into inches, which is what I'm almost comfortable with, you're looking at 50 to 60 acre-inches of water in some places. The average and the mid-South is probably 34 to 36, something like that. We had already saved quite a bit using a practice called zero grade, which means our fields are completely flat. That is actually another topic to consider is, that conservation practices really build on other conservation practices. Some of the things that you do give you the opportunity to do other things. Zero grade, which we implemented very early, gives us the ability to implement AWD more easily than someone who maybe hasn't done zero grade. That gets us in the 22 to 24 range on average. AWD can bring that down to 16 or less, in some scenarios. What we've done here is basically halved the amount of water that it takes to grow rice without changing the yield.
So, if you look at the water to rice yield ratio, that's substantially better. At the same time, we've reduced greenhouse gas emissions anywhere from 16 to 80 percent. At some point in the past, that was certainly valuable societally as far as the impact it has on climate change and air quality, and all of those sorts of things. What we've seen in recent years is that becoming more important to the environment, which is a positive. What we've also come to learn in recent years is that can have an economic benefit as well. What we are seeing is really flowing from the research that created the basis for the modeling, and are able to stand scientifically behind the fact that these greenhouse gas emissions actually are occurring, is companies out there willing to pay for that practice and pay for that outcome to be able to say that they have reduced the greenhouse gas emissions within their supply chain.
I've been happy to take part in projects associated with that, so companies who have made greenhouse gas reduction commitments are able to help meet those commitments because we are able to implement these types of practices on farms across rice-growing regions. Now, what we have is the understanding that these practices matter on a scientific basis, that these practices make a difference, but also that economic incentives sort of offset some of the risks associated with farmers adopting these practices.
Maoya: Tell us a little bit more, or more specifically, of carbon credit validation. What is the information that is required to do these types of validations?
Beatriz: There are, right now, a lot of companies getting into this world of the carbon Market. Everybody wants to do this. They are working fast. In our site, of course we want to do things in an appropriate way, because all that modeling needs to be based on data. So, these companies, they need to have knowledge based on peer-reviewed publications. Different companies are building their own platforms, their own models, but they need to have third party verification. That's how our work became important, because we provide that.
So far, we don't collaborate or do any work with the carbon Markets, but we have been approached with different companies. We are starting to collaborate and to provide data, having companies installing sensors in our fields or doing greenhouse gas measurements. With that data, we can provide more data to validate their models. There is still a lot of uncertainty with the carbon credits. There are a lot of questions. For example, Mark was telling [you about] our research in his farm. We have two 70-acre fields. Even [in] the field [that] is zero grade, you can imagine that [in] a 70-acre field sometimes you have parts of the field that are wet and parts that are dry. We have seen that. In a field with a slope, you will have sometimes that the top is dry, the bottom is wet.
These carbon credits work like, say, you input the data in a model, and then you estimate methane emissions, greenhouse gas emissions. But sometimes, it's not all the field is flooded or dry. Spatial resolution of AWD, for example, is something that these companies need to work more on that. For example, using remote sensing, we can identify how, in a large field or in a large area in a rice-producing county, we can see what areas are under AWD or not. There is still a lot of research on that.
Mark: The core basic research that takes place in places like this are key to unlocking some of the private enterprises out there that make these things work in the economy. Them going to the field, collecting this data, processing that data, publishing the scientific research, measuring it with these methane flux towers, and having real data to stand behind that, is incredibly important in unlocking a lot of opportunity out in the private Markets and in other research in the future. So, we're certainly grateful for that work.
One of the early carbon offset experiences we had happened around the same time we started the measurement towers, but some of the activities predated the collection of data. It was with a local irrigation District that was working with the California Air Resources Board (ARB) protocol on carbon offsets at the time that did recognize some of these practices as creating carbon reduction. They used a model that at the time I believe was likely significantly under-measuring the amount of carbon potential that we had in the field. Also, the process was the proof of concept, and it did that quite well, but it wasn't at the economy of scale that made it possible to be economically viable.
We implemented AWD on a number of acres over the course of a few years. We collected the data that that occurred and were able to have a third party verify that. This was all under a Conservation Innovation Grant to go out and see if this actually worked, along with us and a few other farmers. At the end of that, we were able to sell those carbon offsets through Terra Global to Microsoft. It was a pretty big splash in the carbon ag space, which is quite small, but still very interesting, so it was a lot of fun. About six months later, the check finally showed up in the mail for the carbon offsets that had been issued and sold from the farm.
What I always tell people is, I'll be happy to tell you about the experience and buy you a drink as we do so, but it'll only be one drink! There's not enough money for a second round, that came out of that. It was about $135 for about three years of work, and that was only made possible because the grant covered all the additional charges that came with third party verification and stuff like that.
So, flash forward to now, partially because of the research, partially because of innovation in the private space that's made it possible, we see significantly more opportunities where it's not offsets that are really driving the Market, though I think they're still possibility there in the near future, it's insets where companies who are actually part of that supply chain are willing to pay money to verify and know that they are reducing their greenhouse gas footprint within their supply chain and their Scope 3 emissions, as the Scope 3 emissions make up a significant portion of what accrues to their balance sheet at the CPG (Consumer Packaged Goods) level. That's the best place for them to go out and try to reduce that.
So it's done, really, two things: it's opened up that additional economic incentive for the farmer. In another way, I think it's created the benefit of creating a stronger link between the CPG and the farmer, in just the realization that they have to work together and have to make sure that the CPG recognizes the value that the farmer is creating in the supply chain, not just in creating a carbohydrate or protein, but an environmental asset as well.
Jess: When you're talking about an inset, do you mean the packagers?
Mark: Those directly associated with the space - packaged goods companies, the retailers, all of those that are part of the supply chain in that area who have made public commitments to reduce gas emissions and now have to go about figuring out how best to do that.
Jess: So, on the consumer end, we need to be looking out for those companies and make sure we're supporting those if we want to keep seeing those kinds of projects succeed.
Mark: Absolutely, and you can go online and see where those projects are being done. I'm part of a startup, that is past a startup now, we've been going several years, that works with a number of those companies in making sure that we get farmers rewarded for those types of activities. Consumer packaged goods companies are the ones who are writing the checks to make that money flow to the farmers for those practices to be incentivized.
Note: According to Progressive Grocer, some of the most sustainable grocers in 2023 were ALDI, Mejier, Wegmans, Whole Foods, and Kroger.
Jess: What made you decide to stock the rice paddies with golden shiners, which are a type of minnow? You were able to record 275% growth of those minnows, working with the Resource Renewal Institute.
Mark: That opportunity presented itself a few years ago, and as I mentioned before, having one practice provides a platform to build on and create other practices as well. Doing the zero grade, and then the AWD, helps us save water and reduce methane. One of the questions then is, how do we reduce methane in the wintertime? Because the fields are flooded or another animal, which are the migratory waterfowl.
The rice-growing region through here creates many thousands of acres and many food opportunities for the ducks and the geese that migrate through the here annually, but that also means that the fields are flooded. It's cold that time of year, so you don't see a ton of methane emissions, but there are a few that still come off of those flooded winter fields. There's an organization out of the Bay Area, California, called the Resource Renewal Institute, and they had been doing research on salmon in the fields out there. The goal there was to create growth opportunities for salmon, where they released into the river, so that they could gain a little bit of weight and become healthier before they were released. They applied that same logic to what type of fish would be already in Arkansas, in rice-growing regions here, that they could somehow utilize with the same type of concept.
What they learned was that by introducing fish into the winter flooded environment, they eat the zooplankton which, through a whole series of events, eventually has an impact on the methane emission. By introducing those minnows, you could potentially reduce the winter methane emissions, and at the same time, obviously, you're growing protein, or you're growing fish from a smaller size to a larger size. We began working with Chance & Debb from the Resource Renewal Institute. Year one, they said, put the fish out there and we'll see what happens. We connected them with Beatriz and her team to see what could happen as far as measuring goes because they already had the measurement towers there throughout the winter too.
So, it was again, a win-win across the board. They could collect more data, add another layer to the research. Then, Resource Renewal Institute could learn more about their hypothesis that this could reduce methane from the fields, and then we can see what could potentially happen with the fish. Year one was interesting. Year two, I think the data was more inclusive, and we just wrapped up year three, and are starting a new project this year where the harvested fish were actually frozen. We've installed a small little stand-alone building with a freeze dryer in it for freeze drying the fish. We will package those up for pet treats that we'll market. We're excited about where that goes, because these types of minnows are already utilized as treats for cats and dogs. I purchased some online several months ago. Our dog loved them, so we figured that others will, too. We will be packaging our own brand of those as another proof-of-concept in sort-of creating the whole circular connection there with the field.
Jess: Are you also measuring porewater? Because, I imagine if you look at the smaller scale, you might see more of a change in the water chemistry.
Beatriz: So, besides the measurement of the fluxes with the towers, the third winter we were also measuring with chambers. Also, we were collecting water samples. We were not collecting porewater samples, but we got water samples in the field, in the ditches. I know they were analyzing soil plankton, nutrients, carbon, nitrogen. We had some challenges with those water samples. We are still analyzing the samples.
Jess: When you're harvesting, are the shoots exposed to the air? Can you see, after harvest, methane release from the open shoot?
Beatriz: They just take the grain. So actually, when you see the field from farther or from the road, it looks like it was not harvested. It's a Combine with what they call a Stripper Header. Sometimes after draining the field we see those spikes that are from the methane that is released that was entrapped in the soil, and then after draining the field we see sometimes spikes in methane, especially with the towers. That's the advantage with the towers, because with the chambers we go once per week, so it's hard to see those methane releases or spikes, but we do see that with the towers.
Mark: We don't clip the plant off typically. We're just basically stripping the grain off the heads. Most of the work we do in reducing methane has to do with how we're impacting the soil, not how we're impacting the plant. It's certainly a legitimate question, I'm sure there's something there, but the lion's share of the impact we're trying to have is by how we wet and dry the soil so that the organic matter the soil is not creating that. Other little pieces certainly add up too.
Maoya: So, we're tracking methane emissions. And, of course, this is sort of a reflection of huge shifts and changes and improvements in the biogeochemistry of the fields. What other things are you tracking? What does this mean in the long term for quality of the soil and the quality of the field, the nutrient cycling, and ultimately, productivity of the field?
Beatriz: We do collaborations with other universities that actually, they look more to the biochemistry. We measure the fluxes, so kind of the result of those practices. For instance, we collaborate with University of Delaware. They usually come do porewater samples. That's also related with arsenic. So, one of the things that also, like alternate wetting and drying, besides decreasing water and decreasing methane emissions, can also decrease the content of arsenic in the rice grain. We have all that colleagues that come to our fields and they take soil samples or they do porewater sampling, who study the biochemistry. Methane is decreased, but is because we have the redox conditions in the soil and we are changing from an environment that is anaerobic – it's an environment where the organic matter will the decompose to methane - but if we are adding oxygen, then it will go all the way to CO2.
This year, in one of the fields, we have different sensors. We always welcome other researchers because we already have those fields that we are doing measurements. Whenever there are other universities that reach out to us, say, “You know, we want to install this sensor”. This year, for example, we have automatic chambers, people from Illinois. They are also going to do other samples. We host other researchers that came to analyze soil, to be more focused on soil biochemistry, those things.
Mark: As a broader perspective on how we farm, we use no-till every year that we possibly can, unless we have a fall where harvest is very wet and we have to go back and sort of straighten up some of the field. We do implement minimal to no till every year. So, what we see is a lot higher organic matter in our soil than we see as the state average. The fields that we're doing that work in, and adjacent fields as well, have significantly higher organic matter. That's a definite plus, with the bigger portfolio of practices that we're implementing.
Maoya: How has all this work connected you to other farmers or other committees and allowed people to come together on these types of goals?
Mark: We've had so many different people stop to learn more about it. It has to exceed a thousand visitors over 10 years easily at this point, with different researchers and others stopping by to see that. It's definitely created a lot of curiosity. I think it's also helped destigmatize some of the change in practice for a lot of people, too, to see the research going on here and some of the benefits that have improved from.
It has gone from, really, something that was strange and odd as a practice to something that may not be implemented all over the state now, but people know what it is. People don't find it strange. Many people are experimenting with it, and I think that'll create more adoption in the near future. As a research project, it has been very successful, but also is an outreach product. And that's been large parts of the number of different collaborators of the team from U of A and ARS (Agricultural Research Service), others.
Maoya: Beatriz, how has this experience expanded your mind as a researcher? What are you curious about to explore next?
Beatriz: There is always more to do. I'm curious, for example, in this fish in the field project. We have 3 years and we found the first year some results, then the second were opposite. There are always other variables, we still need to do more research and swap the field, and change the field that we are stocking with the fish, or new techniques. In Arkansas in the last like 10 years, there has been a lot of increase in the row rice production. Row rice is to grow rice in beds, as soybean or corn. We went from 0 to production in 20% of the acre in Arkansas under row rice. So, that's a new practice that needs to get more attention into the research because there are not a lot of studies there, because the acreage has increased a lot.
There is always, like, new cultivars. We need to keep track of what the farmers are doing, what are the new practices they are implementing, to keep doing research. Also, to focus on other metrics like biodiversity. Usually, when we study, like, the effect of one practice, we might have benefits of one metric, but maybe another metric you have a disadvantage, or maybe you have some penalty. We need to have multi-metric assessment and not just focus for one metric. That's also part of the work that I'm involved with Field to Market and the Fieldprint Platform.
So, Field to Market is an organization who brings together different growers, universities, industry. They have this platform for that is called Fieldprint Platform that has 8 sustainability metrics. A farmer can input their data into this platform, or their management practices, and get 8 sustainability metric values. So, you can see how implementing one practice maybe has a positive effect on greenhouse gas emissions but maybe negative on biodiversity. Kind of, looking at the growth rates, not only focused on one metric, looking more to the farm level, not only the field level, are things that we are looking forward to study in the future.
Maoya: What's been really rewarding, and what's the creative vision that you have through this whole effort?
Mark: If you want broad adoption of these types of practices, you have to create economic incentives, and thankfully, this has unlocked that. More recently, we've been able to take advantage of some of that. We want to do it because it's a good thing, ethical thing to do. Getting some economic incentive from doing the right thing is certainly a good thing, too. If we're looking to scale it, it's an absolute necessity. That's made possible by having good research and then, good ways of using that research to model into the future.
As far as other takeaways, the technology is remarkable, as far as its ability to measure what's going on in the field and give us a clear vision, but the technology is nothing without the group of people that work on it. Beatriz and her team, they have somebody there throughout the summer every couple of days drive down from the university. It takes a lot of work. These numbers aren't just coming out of a machine and then being printed on paper. There's a lot of work there.
One funny story I'll offer as I end was, one day back 6-7 years ago, and of course, a lot of these sensors are optical in nature. They have to be able to have a lens that views the laser that is bouncing back and forth and such. I got a call from Dr. Runkle just randomly in the middle of the day, and it he was like, “I don't know what's wrong with the sensor. My team will be out there this week, like they always are. But, can you just go down and look at it and see what's going on?”
As Beatriz mentioned before, we've worked hard to create a lot of biodiversity on the farm and a lot of wildlife habitat. Some of those are birds, and some of those birds are determined to use the sensor as a perch, and you can imagine what might have happened if they did so, and so the sensor was very much covered up in a way that was not allowing any type of research to be done. A couple wipes of a paper towel was able to get that straightened out. These tools certainly require human interaction. That's been the best part of it – it's the ability to connect with a good team of researchers and then all the others that that's impacting acting out there as well.
Beatriz: We clean every week, yeah, and even sometimes in the summer, several times. It's spraying, or sometimes, if there is dust, we see that the signal is not strong enough. So, the sensors cannot read the concentrations of methane or CO2. I would like to highlight something that has been rewarding for me, that is actually to work with this network of farmers. Our main research station, Isbell Farms, have the towers. Since 2018, we work with ten farmers, and they are different. They are early adopters, pioneers in implementing new practices. There were others less willing to implement new practices because they were maybe more afraid or scared. Over time, for me, it has been so rewarding how we have seen the change in behavior from farmers.
We bring them together in a room every year, and they see the results from others, and they see how others are implementing AWD and they have still good years. There was one farmer that, he had never heard about methane before knowing Dr. Runkle and I. He was at the beginning, a little bit scared to try AWD, but at the end, he tried, he liked it, and then he keeps implementing AWD. We, for example, last year have two farmers that got into the irrigation contest. There is an irrigation contest in Arkansas. They participated for the first time in the contest. It's really nice to see how our research can make change, and we see [that] over the years in the behavior of the farmers.