Mike Howell (00:08):
The Dirt with me, Mike Howell, an eKonomics podKast where I present the down and dirty agronomic science to help grow crops and bottom lines. Inspired by eKonomics.com, farming’s go-to informational resource, I’m here to break down the latest crop nutrition research, news, and issues, helping farmers make better business decisions through actionable insights. Let’s dig in.
(00:38)
Well, hello again, everyone. Welcome back to The Dirt. The Dirt is being brought to you this week from Edinburgh, Scotland. We are here at the Sulphur World Symposium this week. I’ve got quite a full lineup this week. They are having the first ever agronomy session here at the Sulphur World Symposium. We’ve got agronomists from all over the world that are going to be talking about the importance of sulphur and sulphur uses in crops. We hope to bring you some summaries of these presentations over the course of the next two episodes. We’ll begin this week, and continue that episode on into next week, so stay tuned, and hope you get some information out of this about sulphur and sulphur nutrition.
(01:16)
Our first guest today is going to be Ron Olson, with the Sulphur Institute. For our listeners that have been tuning in regularly, you probably remember the episode we did on sulphur last year. We had Ron last year with us. He told us a little bit about the Sulphur Institute and what they do. Ron, welcome back to The Dirt.
Ron Olson (01:33):
It’s great to be back. I appreciate the invitation.
Mike Howell (01:35):
Ron, if you will, remind our listeners a little bit about the Sulphur Institute, and what you all are working on there at the Sulphur Institute.
Ron Olson (01:41):
The Sulphur Institute is based in Washington, DC. We’re a trade organization to support the sulphur industry. TSI, as we are referred to as our three letters, the Sulphur Institute has been operating for 60 years. We have 60 member companies globally, and we represent and work with companies that are mining sulphur or capturing it in a recycling effort at a refinery, or just involved in the production of taking sulphur and using it to manufacture fertilizers, or turn it into sulfuric acid, because sulfuric acid is probably the most important chemical that we have, globally, to do so many things in the industrial capacity, and it takes people to market these products and it takes people to transport these products safely, handle them. There’s a lot of connection from the standpoint of all the different companies that supply parts and things. We’re a diverse trade organization that supports sulphur needs around the world.
Mike Howell (02:36):
You and I are both agronomists and we talk a good bit about the need for sulphur and plant nutrition, but one of the things I’ve learned here at the sulphur meetings over the last couple of years is sulphur has a lot of other uses that I wasn’t really familiar with. One thing that I’ve picked up on is the need for sulphur in some of our batteries and the production of batteries lately. There’s a lot of things that go along with sulphur.
Ron Olson (02:58):
Absolutely, and with the need for EV cars and trucks and tractors, et cetera, the need for sulphur to continue to be important part of that, to develop those lithium batteries or the other types of new batteries being developed, sulfur’s going to play a very key role in the future of electrical vehicles.
Mike Howell (03:18):
Today we’re going to focus more on the agronomy aspect. I think that’s what most of our listeners are tuning in for. Here at the Sulphur World Symposium, you’ve had the agronomy steering committee active for a few years now and getting that back in operation, and one of the tasks that you accomplished this year was the agronomy symposium and you brought in some speakers from around the world to talk about sulphur. If you would tell us a little bit about that part of the symposium.
Ron Olson (03:41):
I’m happy to talk about that. This is an effort that the members of the Agronomy Steering Committee suggested right after our Tampa Symposium in May of 2022, and they said as a group, “Well, why don’t we think about having an expanded agronomy series of meetings so we can tell the story about the importance of sulphur and why it really is the fourth major crop nutrient?” We went to work and as it turned out, we have five excellent speakers that are on the panel yesterday, who were so fortunate to have all five of them present. Dr. Ishmael Cakmak from Ismail University in Istanbul, Turkey. Dr. Malcolm Hawksford, from Rothamsted. We had Dr. Shamie Zingor from the African Plant Nutrition Institute educating us about the need for sulphur and it’s a big need for sulphur in the African continent. Very critical, actually. And then Dr. Rob Mickelson from Yara, Director of Agronomy for Yara who’s speaking, as well as Dr. Alan Blaylock with Nutrien.
(04:39)
Those five gentlemen represented… I didn’t add up the years, but there’s a lot of years of experience there about the importance of crop nutrition in this role that sulphur plays. We had a chance to have them all in one room, in a concentrated time, and for me it was like eating a big roast beef sandwich. It was great to sit and hear what they had been doing research on and how their science and their story is going to help the Sulphur Institute really back up the statement, “Sulphur is the fourth major crop nutrient,” and we’re going to expand our efforts to do that.
Mike Howell (05:10):
Ron, that was quite an impressive lineup. We really enjoyed listening to those talks and we’re going to try to get each one of those speakers on the program today and let them summarize their talks for our listeners here today. Ron, one thing that you mentioned with sulphur is the fourth major crop nutrient. That’s something that’s been presented a lot here this week. If you will talk a little bit more about that. Why the need for sulphur and the fourth major crop nutrient?
Ron Olson (05:32):
When being an agronomist who’s been in the industry over almost 50 years now, we are well-trained that the nutrients NPK are so critical and important. The fact, though, is that balanced crop nutrition is where it is. That’s where we’re going to get the most efficiency and the best bang for our buck as farmers make their investment in their crop nutrition plans. But just yesterday when we were listening to these five speakers, they helped us understand that sulphur is inside so many different reactions inside the plant, to move nutrients from the soil into the plant. I’ll just say this. I had missed the importance of how sulphur helps plants trigger the stomata, when it’s under drought conditions, to save water. I always related that to potassium being so critical. Well, potassium is a driver of that, but sulphur triggers the whole process.
(06:25)
I missed that or maybe I was never taught that. That’s why this drilling down deep with these excellent scientists is helping us to see more completely how sulphur, the roles that it plays. And people have said sulphur is the forgotten nutrient. I think it was for a long time. And the Sulphur Institute wants to help create opportunities for that to no longer be the case and we’re going to be at it for a good while. We believe that we all learn through spaced repetition, so I’m going to keep repeating, “Sulphur is the fourth major crop nutrient.” People might hear, may say, “Well, stop that,” but we’re going to keep at it. And that’s an important aspect of what we do.
Mike Howell (07:03):
That’s exactly right. Ron, you mentioned that sulphur is referred to as the forgotten nutrient. And we all know what the Clean Air Act that kind of cleaned up our environment. And that was a great act, we had to do that. But because of that, we’re not getting the free sulphur we used to, and sulphur is coming to the forefront because of that, and I think these speakers did a great job and brought forth that information. Ron, not everybody could travel to Edinburgh to be here for this meeting. I know it’s quite out of the way for everybody to get here, but I do also know that y’all recorded all of these presentations. Is that going to be available for people that weren’t able to travel to Edinburgh? Can they go somewhere and see that information?
Ron Olson (07:38):
They will be able to. We have a task ahead of us to take those videos and link them with the slide presentations. I’m excited to work with our videographer who’s spent the day with us to do that. I would say give me two months to work through those. And yes, we have not figured out how best to distribute them. But Mike, I think you’re going to be willing to help us distribute those and tell that story.
Mike Howell (07:58):
That’ll be great. And as soon as those are available, we’ll let everybody know where to go and see those. We may even get a link to those for the eKonomics website, so our listeners are quite accustomed to going to eKonomics to find some more information. Ron, any other comments? Anything you want to leave our listeners with before we wrap this segment up?
Ron Olson (08:15):
The thing that I would say about our agronomy steering committee is that the TSI is fortunate to have these 12 member companies working together to share their expertise about crop nutrition and the importance of sulphur. And this particular week has been great to knit those relationships closer together. We knew we couldn’t get all of our 12 members of our committee here because of other business obligations, but we’re very excited to keep working on this and keep listening to The Dirt. We’ll keep you posted.
Mike Howell (08:44):
Thanks, Ron. We really appreciate it. I’m joined now by Dr. Shamie Zingore. Dr. Zingore is Head of the African Plant and Nutrition Institute. Dr. Zingore, thanks for taking a few minutes to join us today and talk about what you’re doing there in Africa.
Dr. Shamie Zingore (08:59):
It’s a great pleasure to be part of this podcast. Thank you very much for having me today.
Mike Howell (09:04):
Before we get started, if you would take just a few minutes and introduce yourself to us and tell us what you’re working on.
Dr. Shamie Zingore (09:09):
My name is Shamie Zingore. I am a soil scientist by training. I specialize in soil fertility and the a field of soil science that addresses the ability of the soils to support crop production and ensure that crops receive the right nutrients that they need to produce the optimal yields that are achievable.
Mike Howell (09:32):
That sounds like quite a task to undertake and we appreciate the efforts you’re having down there. Dr. Zingore, in your presentation today, you started off your presentation talking about plant nutrition is at the core of ag sustainability in Africa. Agriculture sustainability is something that we’ve spent a lot of time talking about last season and we know that sustainability is different depending on who’s talking about sustainability, but we definitely support the efforts of sustainability. You also mentioned things like low and unbalanced nutrient applications and some problems that that’s leading to. If you would elaborate on that a little more.
Dr. Shamie Zingore (10:07):
Speaking from the African context, Africa lags behind in fertilizer use when we compare with other global regions. Just to put the numbers into perspective, current fertilizer use in Africa averages just about 20 kgs of nutrients per hectare, and that’s only about 20% of the global average fertilizer use. Africa has this 80% deficit in fertilizer use and that also translates into a large deficit in new production, because currently using Africa for the major food crop such as maize, rice, and wheat, about one and a half tonnes per hectare, and that’s a third of the global average yields, which are average about five tonnes per hectare. That’s why attention to increased nutrient use and also ensuring that we are achieving a balance in the nutrient use is very, very fundamental if Africa is going to increase the overall productivity of agriculture.
Mike Howell (11:18):
We all know the importance of increasing those yields and the productivity. Another point that you mentioned was the low fertility levels that led to the low yields and land degradation. Another result of that is malnutrition and poverty. We understand that it’s important to get these nutrients out there and get these yield levels up so that we’re not affecting the nutrition and the poverty of the population of Africa.
Dr. Shamie Zingore (11:39):
Absolutely. Essentially, for us to get the right food in the right quality, we have to pay attention to feeding the crops well, and this is where the whole concept of plant nutrition comes in. By providing sufficient nutrients in their correct balance, we are able to not only increase the crop yields, but also increase the quality of the crops that are produced. And that means that a better fertilized crop has higher levels of nutrients and that required to ensure that the population that consumes the food produced in Africa is accessing highly nutritional food. I just wanted to emphasize that the large part of the food security problem that we have in Africa, where about 300 million people suffer from malnutrition, is very much related to low yields and low quality of the food produced due to low and unbalanced nutrient application.
Mike Howell (12:45):
Another point you made, you showed some data slides and one of the slides showed that you were able to document a 20% yield gain with only the addition of NP and K, and that’s not including all the micronutrients. 20% yield gain is quite impressive. Talk a little bit more about the 20% yield gain.
Dr. Shamie Zingore (13:03):
On average conditions, the problem of low crop productivity, which is largely due to low nutrient application, but a lot of the research work we’ve done on the continent shows that we can readily increase yields when we supply nutrients in their correct balance. Just by addressing nutrient management, we found in our work that we can increase crop yield by 20%. We are talking about just moving from 20 kgs of nutrient per hectare to 50 kgs of nutrient per hectare, and that’s a major yield gain that can be achieved, and that would go a long way in meeting the food deficits that the continent has.
Mike Howell (13:42):
You talked about why sulphur was so low in Africa and the problems that was caused by the low sulphur fertility. If you would speak a few minutes about those conditions.
Dr. Shamie Zingore (13:51):
Essentially, the issue of sulphur deficiency is expressed in the yields and I did mention that we can readily increase yields by adding NPK, and when sulphur and other micronutrients are addressed, we can further double productivity. That’s an important part of achieving higher yields and higher quality crops, by ensuring that we apply nutrients in their correct balance, including sulphur. And in the case of sulphur, we have a major issue with sulphur deficiencies, which is very pervasive across the continent, and that’s largely because of the low inherent availability of sulphur in the soils. And this is because soils in Africa, some of the oldest in the world, they’re highly weathered and they have very low organic matter, and the large part of the sulphur available in the soils is supplied through organic matter.
(14:45)
And then the second dimension is for many decades, a large part of the African continent here has been cropped with insufficient sulphur application and almost every year farmers remove about three kgs of sulphur from the soil. And for many decades the removal of sulphur has culminated in very low sulphur continents which constrain the yield that farmers can achieve, which makes sulphur fertilization an imperative investment to increase productivity.
Mike Howell (15:19):
Dr. Zingore, we sure appreciate you taking time to visit with us today. I look forward to seeing you around at dinner tonight and hope you enjoy the rest of your conference.
Dr. Shamie Zingore (15:27):
It’s been a great pleasure to be part of the seminar today and a lot of the efforts and some of the discussions are very insightful in what Africa can do to overcome the sulphur deficiency in the soils on the continent.
Mike Howell (15:43):
Our next guest is Dr. Rob Mikkelsen. Rob is Director of Agronomy with Yara and has been around the agronomy world and soil science world for quite a long time. Rob, thanks for being with us today.
Rob Mikkelsen (15:54):
Mike, glad to be with you and discuss some of these important issues that often get overlooked.
Mike Howell (15:59):
Rob, if you will, before we get started, tell our listeners a little bit about yourself and what you do. I know we met years ago back when you were working with IP&I, and I know you’ve had a couple of role changes since then, so let our listeners know a little bit about you.
Rob Mikkelsen (16:11):
Thanks, Mike. I’m a soil scientist and that’s really my first love, but I’ve worked for the US government for a number of years. I worked at North Carolina State University as a professor. I joined a nonprofit called the International Plant Nutrition Institute, and that later took me to living in Africa for several years. And then most recently I’m working for Yara, which is a large international fertiliser company.
Mike Howell (16:34):
We’ve talked a lot about this over the course of the dirt, the Four R nutrient management programme, and you were quite instrumental in the development of this programme back in your days with IP&I. Talk a little bit about that if you will.
Rob Mikkelsen (16:46):
Thanks Mike. That’s one of the things I think I’m really proud of being a part of is this. For our nutrient stewardship concept, we needed a framework to improve the way we’re managing nutrients, and this for our concept arose and we felt like this was a great way to have conversations related to nutrient management, both on a very simple way, something that everyone could relate to about using the right source, right rate, right time and place of fertiliser. But you can get into quite a lot of depth on each of those topics and you’ve talked about those on your podcast, but you can spend hours or days talking about each one of those. You can talk about it at a very educational, almost a very simple level, to apply it to a farm situation, or you can get very deep into the science. I think it meets a lot of needs, something we can communicate to the public that we’re doing a better job of managing our nutrients in a very conscientious, in a very targeted way.
Mike Howell (17:40):
That’s right, Rob. We’ve got to manage these nutrients and make sure that we’re protecting the environment at the same time. We don’t want to be unnecessarily applying these nutrients where we don’t need them. Let’s move in and talk a little bit about your presentation here at the Sulphur Symposium. One of the first things I got out of your talk yesterday was you talked about nutrient interactions. And we’ve talked about that a little bit on the programme, but that’s a subject we really haven’t dived into that deep. Most of the time when I think about interactions, I think about the positive side, but you also pointed out that there were some negative interactions as well. If you will, talk a little bit about the interactions you spoke about yesterday.
Rob Mikkelsen (18:15):
Plants have developed a very complex set of mechanisms where they can regulate their nutrient concentration. Just like in a human body, it’s not surprising that if you change one thing, something else is often changed. High blood pressure, for example, can change lots of other things within our body. Sometimes we do things that are beneficial for our body, sometimes they’re not beneficial and can be harmful in the long run. Many of the plant nutrients are like that too, and we change one nutrient in the plant, it impacts another one. Some of the ones we commonly think about are phosphorus and zinc. Those have a negative interaction. With high phosphorus, sometimes we can induce a zinc deficiency. The one that we spent most of our time talking about yesterday was sulphur and nitrogen. Those are very closely related in amino acid production and then in protein production.
(19:04)
A lack of nitrogen causes the sulphur not to be used properly, or a lack of sulphur causes the nitrogen not to be used properly. It’s one of those that you can’t just only add nitrogen or only add sulphur, but you need the right combination of both of those to be effective for plant health.
Mike Howell (19:20):
Rob, I don’t know if you listened to The Dirt that often, but a couple of weeks ago we had Dr. Glenn Harris with the University of Georgia on talking about cotton and peanut fertility and that’s one of the things he mentioned was the nitrogen and sulphur ratio, and how important that was and especially in cotton production. Is that true in most crops that we’re talking about? I
Rob Mikkelsen (19:38):
Think it’s every crop we talk about. And how that interaction manifests itself may be different in different crops. Sometimes, for example, in nitrogens and fixing plants could be beans or peas or peanuts, could be lots of things, and nitrogen and sulphur is especially shows up in the nitrogen fixation. Those rhizobia are not able to function properly and then the nitrogen that they do fix doesn’t get assimilated into the plant properly. But we see it in other crops. For example, in canola, that’s another one that has a fairly high sulphur demand. And if there’s not proper sulphur, the yields are severely suppressed, and also the oil ratios are not what we want when that nitrogen and sulphur ratio is correct. And it shows up in wheat. Not only are yield suppressed when there’s not adequate sulphur, but the baking quality of the flour that comes from the wheat, where there’s insufficient sulphur is diminished and the loafs of bread don’t rise properly. It’s essential for every crop. It’s just the way that it’s manifested may be different in different crops.
Mike Howell (20:41):
And that was something else I was going to bring up. You talked about the increased yield with the proper ratios of nitrogen and sulphur. You mentioned the baking quality. Another thing that you mentioned yesterday was the fertiliser recovery from the soil. If we have this ratio correct. Talk a little bit more about that.
Rob Mikkelsen (20:55):
Again, these interactions are so important in everything that we do and often get overlooked. This ratio of nitrogen and sulphur need to be preserved in the plant, and often it ranges between 12 parts of nitrogen to one part sulphur, maybe up to 16 parts per million of nitrogen to one part sulphur. When that ratio is disturbed, maybe if there’s a surplus of nitrogen, or deficiency of sulphur, or maybe a surplus of sulphur and deficiency of nitrogen, when those ratios are off the plant metabolism just doesn’t function properly. We put on our nitrogen fertiliser following good recommendations following the Four R practises. But sulphur is deficient, the plant can’t take up that nitrogen and it can’t use that nitrogen properly.
(21:38)
And a number of studies have showed that applying nitrogen fertiliser with a deficiency of sulphur, that nitrogen stays in the soil. And with all the environmental talk that we have, and Mike, you’ve addressed this in the past, we don’t want nitrogen staying in the soil not being taken up by the plant. When it stays in the soil and we get a rainfall that can be lost through leaching down into groundwater, and that’s a concern in some of our agricultural areas. When that nitrate stays in the soil and we get again, maybe a flooded condition, we can lose that nitrogen through denitrification. A lot of ways we don’t think about the soil when we’re doing the fertiliser, we’re thinking about plant nutrition. But a lack of sulphur causes that nitrogen to remain in the soil and not be taken up, and then there can be some unintended environmental consequences that we’re trying to avoid.
Mike Howell (22:27):
One thing that you did point out was when we have the adequate sulphur, you talked about reducing the nitrate leach in. You talked about nitrous oxides’ reduction a little bit, and you also talked about as much as 15% increase nitrogen recovery.
Rob Mikkelsen (22:40):
That’s something that I hadn’t thought about for a while, that again, it shouldn’t have been surprising to me, but all of these things are related. A deficiency of one nutrient causes a disruption in the metabolism in another. And Mike, you’ve seen and talked about the barrel example, which we use commonly in sulphur fertility. Or the stave of one, that’s the shortest limits the nutrient efficiency of the other nutrients. And this is a basic concept we learned probably in the first day of our agronomy training, and I’m not sure why it took me so many years to relearn that.
(23:12)
But when sulphur is deficient, nothing else is going to be used properly. And that includes zinc, it includes some of the micronutrients, includes nitrogen, which we’re talking about today. But all of these things have to be managed properly and we have to get away from our focus of one single nutrient at a time. And so, today it was a good reminder that we need to consider sulphur because that’s one of the nutrients that often gets overlooked. We think about N, P and K, often the micronutrients, but sulphur just hangs out there in the background and often doesn’t get the attention that it needs.
Mike Howell (23:45):
That’s exactly right, Rob. One other thing that you talked about different ways that we could lose sulphur from the system, and we don’t think about that an awful lot, but we can lose sulphur much like we do nitrogen. Talk a little bit about how sulphur can be lost and how we can protect that sulphur and keep it in the system.
Rob Mikkelsen (24:02):
That depends very much on the soil, of course. But we find that in most soils, the majority of the sulphur is tied up in organic matter, and that’s very similar to nitrogen where we know we’re going to get some mineralization of soil organic matter every year and a small amount of that nitrogen will be released for the plant. Very similar to that is the sulphur. The sulphur is tied up in organic matter and that slowly is mineralized by soil microorganisms. They estimate that up to 99% of the total sulphur in the soil is present in organic matter. Every year, that’s leaking a little bit of sulphur into the soil solution. And generally there’s just a few parts for a million of sulphate, which is the form the plants take up in the soil solution available for plant nutrition. The soil organic matter is slowly breaking down and maybe slowly building as well as we try to build soil carbon.
(24:58)
But that sulphate behaves very similarly to nitrate, and it’s well known that nitrate will leach out of most soils. The cation are held tightly on the cation exchange sites, but the anions generally are not held onto the soil articles or soil organic matter. Similar to nitrates, sulphate is very susceptible to leaching, and that’s probably one of the biggest loss mechanisms is washing it through the soil down below the root zone. In very acidic soils, the soil properties change somewhat and in acid soils, the sulphate can actually bind to the soil particles, but that’s not at a pH range that we try to grow our crops. That’s down at pH five or four or even three. The sulphate can be absorbed under the soil, but it’s at pH, it’s very harmful for the roots to grow because of aluminium toxicity primarily. A large amount of this sulphur fertiliser that we apply eventually will get washed out below the root zone.
(25:53)
When this happens with nitrate, we’re very concerned because nitrate has some big implications for water quality, whether it’s for drinking or maybe stimulating algae growth, or doing some unintended consequence. With sulphate, we don’t really worry about the environmental aspects of sulphate leaching like we do with nitrate. With sulphate, one of the biggest concerns is when it gets to a high concentration, the water tastes funny. I think we’ve all experienced water where there’s some sulphur there and we’re going, “It doesn’t taste like I would like it to.” At very high concentrations of sulphate in drinking water, it starts to cause some stomach upset, but no real serious harmful impacts like nitrate does.
(26:34)
We don’t really talk much about the environmental impacts of that sulphate leaching from the soil like we do with nitrate. But like anything, we’re applying a fertiliser, we want to get as much of it in the plant as we can. We don’t want it to wash below the root zone. Going back to the Four R discussion that we began with Four R practises of managing that source rate, time and place can allow us to get the most sulphur into the plant, just like there is to get the most nitrogen into the plant.
Mike Howell (27:01):
Rob, we really appreciate you taking time to visit with us today. I’m sure our growers are getting a lot of useful information from this. Is there anything else you want to add before we wrap this up?
Rob Mikkelsen (27:09):
Mike, I really appreciate your efforts to educate people about using nutrients in the best way. Sometimes fertilisers get some disparaging words about why do farmers use all this fertiliser and what about some of the negative things about fertiliser? But really, there’s no single invention in the world beyond mineral fertilisers that have done more to benefit the human family, to raise people out of poverty, to provide good nutrition, to eliminate hunger. Yes, there are some problems with fertilisers and we have a long way to go to managing the best way, but they have been such a tremendous blessing for humanity, and I get a little defensive sometimes when people only talk about the negative things and overlook the great benefit that they are for the world. I appreciate your efforts to educate people, Mike, and help us do a better job, but to appreciate this miracle that we have in modern agriculture.
Mike Howell (28:03):
Thank you, Rob. Let you get back to the conference now. We really appreciate you stopping by.
(28:09)
Well, listeners, we’re now ready for our second segment today. And if you’ve been listening, you recognise that we’re going to start talking about our famous person in agriculture. Today, since we’re in the United Kingdom, I thought it would only be fitting that we talk about somebody from the United Kingdom and their contributions to agriculture.
(28:25)
The person we’re going to talk about today is Jethro Tull. He was from Berkshire, England. He lived from 1674 to 1741. He grew up on a farm and later on in life he actually took over his father’s farm and farmed that for a while before purchasing his own farm. But in 1699, Tull had trained to be on the bar and actually passed all of those tests and 10 years later was called to be a lawyer. He chose not to do that and continued working on his father’s farm. In 1701, he actually invented a horse-drawn seed drill that was an economical way to sow seeds into neat rows, and much like the grain drills that we still use today, this was a big advance over the way that grain was sown in the past where they actually just threw the seed out by hand.
(29:12)
But this invention really revolutionised the way that grain was able to be planted, and it is still used much to this same method today. Today we want to thank Mr. Jethro Tull for his contributions to the grain drill.
(29:26)
Well, listeners, we hope you enjoyed this first session from the Sulphur World Symposium. We’ll be coming back next week and bringing you the conclusion of this episode with more information from the speakers this week. Until next time, this has been Mike Howell with The Dirt.
