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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, use 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. We’re continuing our series on sulphur from the Sulphur World Symposium. Today, we’re going to bring you a few more speakers from the agronomy session that gave some research information about sulphur and sulphur nutrition. Our first guest today is Dr. Alan Blaylock. Now, if you’ve been listening to The Dirt for very long, you’ve heard Dr. Blaylock several times. Dr. Blaylock is senior agronomist with Nutrien and my colleague in the western part of the United States. Alan, welcome back to The Dirt.
Dr Alan Blaylock (01:08):
Thanks, Mike. Good to be on with you again.
Mike Howell (01:10):
Alan, I know you just finished a presentation here talking about some research papers that have recently came out talking about sulphur and the increased use of sulphur over the last 20 years or so after the Clean Air Act and we don’t have as much free sulphur anymore. Tell us a little bit about what those papers were talking about.
Dr Alan Blaylock (01:26):
What those papers were looking at, there was some research looking at sulphur use over the last several decades and in relation to atmospheric deposition, which has obviously declined since the Clean Air Act, and basically evaluating this idea that sulphur that farmers used to get for free from atmospheric deposition, it came from emissions from factories, power plants, et cetera, it’s kind of disappeared and farmers now have to use more fertilizer sulphur and sulphur for other agricultural applications, like sometimes as a fungicide, sometimes as a soil amendment.
(02:02)
So really looking at that balance over time, how sulphur uses has been increasing for agricultural purposes, but particularly also evaluating potential risks of that increased sulphur use. Are we creating maybe some specific environmental hazards from that increased use? So the paper was looking at this balance of sulphur use and what’s being used and trying to evaluate that and get a handle on that.
Mike Howell (02:25):
Alan, you just highlighted three ways that we can use sulphur in agriculture. The first, and we’ve talked about this several times on the program, is sulfurs are used for a fertilizer. We’ve also talked about sulphur as a fungicide, and that’s something that a lot of people really don’t understand, that sulphur has some fungicide properties. And also, we can use sulphur as a soil amendment. Now, do you want to talk about those other two aspects a little bit, the fungicide properties and the soil amendments? Elaborate on those a little bit?
Dr Alan Blaylock (02:52):
Sure, Mike. Elemental sulphur, when used as a powder or a dust applied to the plants, is very effective at controlling some certain diseases such as mildew, powdery mildew specifically, and it’s used in certain crops. Grapes in California was the example used in the paper. When I was young, we grew sugar beets on our farm. We had problems with powdery mildew and we used elemental sulphur powder to control that. Just dust that onto the crop and it was very effective economical fungicide, and really in looking at that as a fungicide might be preferable to using some of our other chemical fungicides. So certainly a lot of merit in that use.
(03:30)
The other use is as an amendment. Now, sulphur can be applied as a soil amendment for different purposes. Elemental sulphur, when it reacts in the soil, produces acidity. For example, we have a high pH soil and it causes problems with other nutrients, or certain crops may be better adapted to acid soil, so we can use elemental sulphur or sulfuric acid, which is another form, to lower the soil pH for some of these specific cases.
(03:58)
Another amendment use of sulphur is the use of gypsum where we apply gypsum as a calcium source and we may use fairly high rates of that. And there are certain crops where that’s extremely beneficial. Peanuts, for example, have a really high calcium requirement. We have to have a lot of calcium in the soil solution, and gypsum is a very economical way to apply that.
(04:20)
Gypsum also promotes favorable physical properties of the soil. The calcium in the gypsum flocculates the clays, makes the soil more permeable, better soil tilt at the surface, and so it sometimes used for that. Now, out in the Western US, we sometimes have what we call sodic soils, and these are soils that are affected by salinity, where sodium is a dominant salt and that sodium has very negative effects on soil physical properties. So to remediate those, we need to use a calcium amendment. So gypsum is very commonly used. And the calcium will displace the sodium and then we can leach the sodium out of the soil. So it’s used as an amendment for several different purposes, but usually around those purposes I listed there.
Mike Howell (05:07):
Alan, we know we have to have sulphur for plant growth and development. It’s one of our essential nutrients, and we’re classifying it as one of the top four nutrients here at the Sulphur World Symposium. What would be the dangers of putting out too much sulphur as some of these papers indicate? What kind of problems could we lead to if growers were overapplying sulphur?
Dr Alan Blaylock (05:25):
The main concerns that have been expressed for sulphur, and let’s talk specifically about downstream effects of sulphur that might be lost from the field, the main concerns are related to the sulphur in waterways, bodies of water, particularly where sulphate sulphur gets reduced to sulphide sulphur, which is just a different form of sulphur, but that sulphide sulphur can have some toxic effects in several different ways. And so the concerns about sulphur loss from the field and the environmental hazard, so to speak, would be the concerns about what sulphur does in those downstream bodies of water and its effect on other organisms in those bodies of water.
Mike Howell (06:12):
Alan, we’ve spent a lot of time talking about nitrogen and nitrogen management, how we can keep nitrogen in the field and make it more effective. Can some of those same tactics work as far as managing sulphur and making sure we’re not letting that sulphur get into our waterways?
Dr Alan Blaylock (06:26):
Absolutely. That’s a great question because nitrogen and sulphur are very similar in the soil and in the plants. Sulphur undergoes many of the same transformations that nitrogen does. Sulphate sulphur can be leached from the soil like nitrate nitrogen. And so a lot of these transformations, a lot of the soil chemistry, the physical behavior of sulphate in the soil, very much like nitrate. So the same practices that we use to keep nitrogen in the soil could also be used and should be used to keep sulphur in the soil, particularly sulphate sulphur, which is the plant available for them. That’s what plants are taking up. And so keeping that in the soil, the management to keep that in the soil would be really the same as the management for keeping nitrate in the soil.
Mike Howell (07:12):
So it sounds like if growers are using these practices already and understand how to apply them effectively using the 4R nutrient management strategies that we’ve talked about, really we may not have a lot of problem. It may just be a perception of a problem that we need to do a little more work and document that nothing bad is actually going on.
Dr Alan Blaylock (07:29):
I think that’s very true. I think we need a better understanding. As was pointed out in these papers that I was discussing, I think we need a better understanding of sulphur behavior. We need a better understanding of its downstream effects. We need to know are we really losing it or not? And certainly there are environments if we have sulphate sulphur in a sandy soil, yes, the potential for leaching is real. We can use our best management practices, go back to our 4R principles, apply the right material at the right rate, at the right time, and in the right place. And by doing so, I believe we can keep that sulphur in the soil to get the maximum value out of the sulphur inputs that we have to put on the crops these days.
Mike Howell (08:11):
Alan, I know you’re busy this week. We’ve got a lot of activities going on. Is there anything else you want to leave us with before we wrap this up?
Dr Alan Blaylock (08:18):
It’s great to be here at the Sulphur World Symposium again, and I think working with this group gives us the opportunity to examine a lot of these aspects of sulphur and learn more about the sulphur industry, but also to share our agronomic expertise with some people here who are maybe not as connected in ag because we have manufacturers, we have transporters, we have the whole spectrum of the sulphur industry and gives us a chance to interact with them to share our knowledge of sulphur as an agricultural input, a very valuable input and very much needed, and really to stress our message that sulphur is the fourth major crop nutrient and it’s increasing in importance all the time.
Mike Howell (09:05):
Alan, thanks for joining us and enjoy the rest of the symposium.
(09:09)
Well, listeners, we weren’t able to get all of our speakers from the symposium on today. We really tried to do that, but due to time constraints here, we weren’t able to get everyone. I wanted to take just a minute and talk about Dr. Ismail Cakmak. Dr. Cakmak earned his PhD at the University of Hohemheim in Stuttgart, Germany and is a full professor at Sabanci University in Istanbul, Turkey. Dr. Cakmak has published over 230 peer-reviewed articles and is named among the highly cited researchers by the Clarivate Analytics. He’s also ranked in the top 0.05% of the most influential scientists in all scientific disciplines in 2022 by Stanford University.
(09:53)
Dr. Ismail Cakmak gave a presentation talking about sulphur, the fourth major crop nutrient. He talked about reasons for sulphur deficiency, and some of those included the reduction in atmospheric deposition that we’ve already talked about. He talked about low organic matter in soils and increased yields in crops requiring more sulphur because of the increased yields. He also talked about some of the issues associated with low sulphur fertility. That’s going to lead to reduced yields, increased susceptibility to stresses because sulphur is so important as a stress regulator in plants. He also talked about some food safety and environmental concerns.
(10:32)
Dr. Cakmak also talked about the importance of sulphur to regulate drought stress in crops. He talked about the sulphate movement from the roots to the chutes and how that’s important in regulating stomatal openings and helping the plants get through times of drought stress. He also stressed the importance of disease tolerance as related to sulphur nutrition and how the plants can overcome diseases with adequate sulphur nutrition.
(10:59)
And finally, he talked about hidden hunger. Now, hidden hunger is the result of plants not being able to take up the necessary nutrients that we’re needing in our diets. Two of these are zinc and iron and they’re both directly related to sulphur nutrition. If we have low levels of sulphur in our crops, that’s also going to reduce the amount of zinc and iron that those plants are able to take up. Therefore, it’s going to lead to zinc and iron deficiencies in our food sources. This is a big problem in a lot of our underdeveloped countries around the world and thus the need for sulphur in a lot of these areas.
(11:35)
Our final speaker that I wanted to talk about is Dr. Malcolm Hawkesford. Dr. Hawkesford leads the Institute Strategic Program designing future wheat varieties. He’s published widely on biochemistry and molecular biology of plant nutrition and is internationally recognized for contributions in the field of plant nutrition, particularly with regard to nitrogen and sulphur. He also leads the field phenotyping project at Rothamsted Research.
(12:04)
Dr. Malcolm Hawkesford talked about sulphur use efficiency in crops and he did this from a physiological perspective. He talked about a lot of the drivers in this research were yield of the crops, profit for the growers, and the quality of the end product. He focuses research on genetic improvements to make more efficient crops. He talked about sulphur use efficiency and how that’s related to yield, uptake of the nutrients.
(12:30)
Another important topic that Dr. Hawkesford talked about was transporters and how these transporters are necessary to get sulphur from the outside of the cells into the cells, and he identified multiple different transporters that are responsible for this process. He talked about different ways, different keys to improve efficiency, how to ensure sulphur availability, and how to get sulphur into the plants. Dr. Hawkesford talked about key ways to improve sulphur use efficiency. He talked about how to ensure availability and how to make sure that we get the sulphur into the plant where it can be used.
(13:07)
Listeners, it’s time for our second segment today where we talk about a famous person in agriculture. Because we’re here in Scotland, I thought it only appropriate that we continue talking about this part of the world and somebody famous from the European community. Today we’re going to talk about Sir John Bennet Lawes.
(13:24)
Mr. Lawes was born in December of 1814 and passed away in August of 1900. He was an English entrepreneur and an agricultural scientist, and he founded an agriculture experimental farm at his home at Rothamsted Manor. Eventually, this farm became known as the Rothamsted Research. It was here that Mr. Lawes developed a super phosphate and that would mark the beginnings of the chemical fertilizer industry.
(13:51)
Now, when Mr. Lawes was a young child, his father passed away, Lawes inherited the family home, and later he donated part of this farm to be used for agricultural research. Rothamsted Research, as it eventually became known, is the oldest agricultural research farm in existence in the world, and it is still in existence today, still conducting a lot of important research that’s used not only here in Europe, but also around the world.
(14:20)
Listeners, I know I’ve really enjoyed my time here in Edinburgh. Going to be a long flight back home, but it’s time to get back home and get back to work. We hope you’ve really enjoyed the episodes that we brought you here from the World Sulphur Symposium. A lot of great information on sulphur and sulphur nutrition and how we use sulphur to produce healthy crops. For more information about sulphur, you can always visit our website at nutrien-ekonomics.com. Until next time, this has been Mike Howell with The Dirt.
