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Mike Howell (00:08):
The Dirt with me, Mike Howell, an eKonomics podcast 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. Now, if you tuned in last week, you got the first part of this episode where we’re talking with Dr. Antonio Mallarino, Professor Emeritus with Iowa State. He’s spent his career researching P and K and micronutrients as well as lime recommendations. And we have Alan Blaylock, a familiar face with us. He is a Senior Agronomist with Nutrien, and he’s been a guest on The Dirt for many times. We wanted to continue our conversation today about P and K.
(01:05)
Dr. Mallarino, welcome back to The Dirt. We started our conversation last week and we didn’t have time to finish everything, but wanted to pick that back up to today. We’re entering fall here across the country and harvest season is in full swing and many growers are going to be looking at making P and K applications this fall. Now, is this what we consider a best practice to make these fall applications, or should we wait until later in the year or closer to planting time to make these P and K applications?
Dr. Antonio Mallarino (01:32):
Yes, it is a good idea to apply the fertilizers in the fall. That’s something else that I have been researching is there is differences with the fall application or the spring applications and things like that for phosphorus and potassium. And the snow is no difference. And in fact, I believe that, for example, many people give credits to the P and the K in the manure that they apply, there is a lot of manure being applied in Iowa. That as for the P and K, it is better if they apply in the fall. And then come my colleagues from the nitrogen and say, “No, they should apply in the spring because the nitrogen and the losses.” A, I don’t care about nitrogen, I care about P and K. So it’s better to put in the fall.
(02:16)
Yes, I like to qualify that because although the climate is changing, we are getting a bit more rainfall in the fall that we used to in Iowa, more uncertain. After harvest in the fall before soil freezes or we get snow is the best time to do tillers for those farmers that do tillers and also to apply the P and the K, be with incorporated or not.
(02:41)
And then one thing that I investigated a lot was the issue of the water quality and mainly the impact of phosphorus application and manure in the fall. See, when you hear what the wind brings from the east sometimes and the northeast, hey, that’s another planet, we are in Iowa, south Minnesota, Illinois, that’s not the same as the Great Lakes. So we don’t get as much snow, we don’t get as much liquid rain, so application of phosphorus before soils freeze, before snow, and potassium, that is a BMP. It is a best management practices even in no till. Because, and that’s what I did lots of research on with several publications, when you have that fertilizer there or the manure, then you get the snow and then start reacting with the soil, you see? The Iowa soils retain phosphorus and potassium, do not fix necessarily, you see?
(03:43)
But retention is a good thing because that means that when it comes snow melt or the spring rains, there is not much extraction of soluble P because that is what create the problems. Now of course, if there is soil erosion, yes, there is an issue. So I have the proof that that is a good practice. Now, it can be applied in the spring too. The problem is that two, three of 10 years, farmers cannot apply anything the spring because it’s too wet or they have to delay planting. The important thing is plant. So it’s a good practice, it should be done. But what is not so good, especially in areas that there is slope, and we have some slope in northeast Iowa, Southwest Iowa, is people spreading fertilizer or manure on frozen soil in the winter.
(04:35)
I’m sorry, guys, that’s not a good idea, because okay, let’s say that you apply that in say middle of December, there is not much snow. Well, if there is snow, snow melt or not rain until April, that’s okay, but we can have those 4, 5, 6 inches of snow in February. We can remember, one January we have liquid rain in the middle of January, so try to apply the P and the K in the fall before snow. But I have a couple of other things that I could tell you, unless you have another question.
Mike Howell (05:14):
My whole career, my whole life really, I remember everybody is always applying the P and the K in the fall, and that’s the way I recommend doing it as well. But there’s some people now that are also saying that it may be better to wait and put this out in the spring.
(05:29)
Alan, down in Mississippi in my neck of the woods, we can actually leach some potash from the soil. In extreme sandy conditions, these low CEC soils are definitely not what we’re looking at here in Iowa today, but more and more people are talking about delaying these applications. Now, agronomically, I don’t know that there’s going to be a big difference. That’s their reasoning, they say the plants can take it up better, get more of those nutrients into the plants if we make that application in the spring. But it brings up another issue, and that’s logistics. Alan, can we actually transport all of this fertilizer that we need in the spring of the year and get it applied to the crop and get it out there before the crop starts coming up and starts needing these nutrients?
Dr. Alan Blaylock (06:08):
That’s a big part of the equation, Mike, and I think we sometimes overlook that and we get focused on the agronomic recommendations. There may be cases where it might be preferred to apply in the spring. But I think before I directly answer your question, I want to remind growers that in our discussion, really a lot of these things are site-specific. There are things that apply in Iowa and these fantastic soils that we have in Iowa and Illinois and Southern Minnesota that are very forgiving in reality. There are things we can do there that we may not be able to do other places. And there are things that work well here that may not work other places. So in any case, in any fertilizer management decision, we need to make sure we’re focusing on those site-specific variables that influence that because there are some cases where a spring application might be preferred for various reasons.
(07:03)
So, to answer your question about logistics, much of our corn belt fall application of P and K really is a good practice, and it works very well because we have an environment that’s suitable for that. We have good soils that grow great crops and give us a lot of flexibility. Like Antonio said, we’re really blessed here in the Midwest and especially in Iowa. This is a great combination of climate and soil, and there’s probably… maybe Illinois, but probably there’s no better combination of soil and climate to grow corn and soybeans than right here where we are. So we want to remember that and remember that it’s highly variable.
(07:40)
But, the logistics, we’re trying to move millions of tons of these fertilizers in a fairly short period of time. There are warehouses that have to hold this, there are barges, there are trains, there are trucks that have to get it delivered. And then once it’s at the retail facility, it has to get applied. And just think about corn alone, we’re talking about something in the range of 95 million acres of corn and close to 90 million acres of soybeans in which we’re trying to get fall work done. Lots of times we do those applications on the corn and not on soybeans, but still think about the magnitude of that number and the millions of tons of fertilizer that have to get delivered. And as Antonio said, sometimes in the spring we can’t get in the field. So waiting until spring may really put you in a bind to where, oh, maybe I can’t get in the field to apply the fertilizer. Now what? Now my crop is not going to have what it needs even if I can get it planted.
(08:42)
So because throughout this region that we’re in today, here in Iowa, in neighboring states, that fall application is a good practice, we should try to get it done to avoid not being able to do it in the spring because there’s risk in waiting. If we get a window of opportunity in the fall to apply P and K, we can make sure we have those nutrients in the field and not run the risk of missing out in the spring, which then translates to maybe delayed planting, not getting the fertilizer on, which then projects to lower yields and profit loss. So this is a big system, and there are millions and millions of acres that have to get serviced and the infrastructure is built to apply a lot of this in the fall. Let’s take advantage of that.
(09:35)
And trying to get everything applied in the spring runs a high risk of not being able to get the product, not being able to get it in the field once we have it. And so there’s a lot of risk in waiting until spring. Again, very site-specific. We have listeners from all over the country. Not everybody has these great soils in Iowa and Illinois that we can do that. So again, caution the listeners, know your local conditions and know what is really possible for your local area, and plan accordingly. Take those things into account and know what you’re going to be able to do logistically.
(10:13)
I remember a farmer, this is talking about nitrogen, a farmer here in Iowa once told me, “Well, I’ve got 5,000 acres of corn. I like to side dress, but I know I can’t get all of that 5,000 acre side dressed. So what am I going to do with those acres that I can’t side dress in any given year?” So you have to plan ahead. And the same thing would be true for P and K. Know what you’re capable of and what is good practice for your operation. It’s a puzzle, we have to fit all those pieces together, but logistics is a big part of that.
Mike Howell (10:44):
Alan, that’s exactly right. It’s a puzzle and everybody’s puzzle may be a little different. I’m not sure about the area here that we’re sitting in today, but in South Mississippi we have resistant weed issues. We have resistance to just about everything. Italian ryegrass is one of our big resistant weeds, and we just can’t kill that once it comes up and gets over a certain stage. The practice now is to after you put out your fertilizer in the fall come back and put your residual herbicides out in the fall. And they don’t want anything to go through that field until the planter. They want the planter to be the first thing in the field in the spring to maintain that residual herbicide. So situations like that are going to prevent us from making spring applications a lot of times. Growers just have a lot to do in the spring, and it’s going to be hard to get all of this fertilizer put out in the spring. Dr. Mallarino, you have any comments on this?
Dr. Antonio Mallarino (11:32):
I just want to say that no wonder I’ve been working together with Alan and some others from your company for years, I mean, we are in agreement in so many things. Now, as he said here, we don’t have large areas of sandy soils in Iowa. Actually, some farmers call sandy stage two that is loam. Oh yeah, it’s kind of sandy. Okay-
Mike Howell (11:54):
Let me interject, I’ve got a quick story about sand here. I used to be the peanut specialist in Mississippi with Mississippi state. They started moving peanuts into the Delta and everybody thought that the Delta was really sandy soils. I learned really quick that the definition of sand in the Delta was if you could wash it off your truck with a pressure washer that was sand. If it wouldn’t come off of your truck, that was clay. So everybody’s sand is a little bit different.
Dr. Antonio Mallarino (12:18):
Yes. But after having said that, there are a few pockets. For example, we have here in central Iowa, the Sparta soils. Now, it is just minuscule. In the north central region, you don’t need to go to Mississippi, you go to the sandy soils around the Twin Cities in Minnesota and around Wisconsin, near Madison, Michigan, Northern Indiana. So we do have some sandy soils. And for example, here in Iowa, for alfalfa for example, we recommend fertilization, especially potash in the fall. That’s important for persistence to avoid winter killing. But when there is a big rate to apply, we do recommend splitting it in the fall or even in late summer because for example, alfalfa, you are harvesting everything. You got a high rate of potassium, you get two, three cuts, you are removing tons of potassium there. Not phosphorus, lot of potassium. We have this is called luxury uptake. So they absorb the potassium even it’s not needed. So if you put a huge amount there, and then maybe by the third, fourth cut, you don’t have enough there, so you should apply. So yes, there are different soils.
(13:29)
No, the other thing I want to say is a bit different, which relates to logistics too, but the logistics of soil sampling. In order to apply in the fall, most farmers take soil samples every four years for the consumer rotation. I say that they should sample every two years, but anyway, but most don’t want to do it. The issue is that everybody, the farmers, the dealers, the agronomists, the co-ops that take these soil samples, the soil sampling companies, they are very anxious that they go sampling behind the combine. They combine today, tomorrow they’re already there taking soil samples and then applying the fertilizers.
(14:16)
It is very important for potassium and for pH, those two mostly, be careful when you have a drought in late summer, early fall. You see, you have no rain. Even if the rain was fantastic up to July or early August, you have no rain from the middle of August until harvest, and then you go and take a soil sample, say late September [inaudible 00:14:45] October behind the combine, wow, your potassium soil test maybe 40, 50 ppm higher than it should be because the recycling didn’t happen. That’s another work that I did with phosphorus and potassium. The phosphorus comes out of the residue or the standing plants very slowly until the spring. The potassium in soybean, if you get the normal rain that we get in Iowa, by the middle of November, late November, about 80, 85% of the potassium wash off into the soil. From the time that the soybeans start to yellow, losses start there.
(15:23)
So remember, 80% of potassium in soybean may be that 100 pounds of potassium being applied quote there. So if you come, it had been dry, and if there is some sample, you’re screwed because it will bias toward the soil value lower because of this, and that even farmers and consults have seen that. So the solution is not easy, but I tell them my recommendation is wait until you get a couple of inches of rain or at least until you moist the top six inches. But people don’t want to wait, and that’s the problem. Because they want to take example, they want the test result, and they go to apply fertilizer. So from that perspective, maybe it’s better to wait until the spring because you can delay that sampling, do the analysis. The labs can do the analysis over the winter. They don’t have to cut corners.
(16:19)
Some labs get 100,000 samples in a week and they have to cut corners. They don’t like when I say this, but they do cut corners. The testing could be easier, could be better, and then they have the time to apply in the spring. So you need to consider that part of the logistics.
(16:37)
The other is pH. Those exactly same conditions that you get lower potassium that should be, you get more acidic pH because there is not washing of the soluble salts that are there in the soil. So let’s say if you were going to get a pH 6 and you had August and September drought, you take a sample, that pH instead of being six, it could be 5.4 or 5,.5. So then the family would go with the liming when you don’t have to. So those are some caveats that you need to do.
(17:13)
Part of my research that I’ve done about 20 years ago, some consultants, some say, “Antonio, we are going to sample soybean ground at above V5, V6.” “Huh?” And they say, “Yeah, because you have shown all these issues that may happen, especially with potassium because of recycling, the rainfall, and all the drought. By that time all these things happen, so the testing that time could be reflect better what is availability.” “Yeah, I know, but then you need to wait to apply until the fall because you cannot apply the potassium there and you had to estimate the removal in order to do application.” But I showed that it’s not a big deal. I was afraid that the results are going to be affected by the high temperature for things like that, but they don’t.
(18:03)
So now I have several companies and soil samplers that they say, “We cannot take all the samples that we need to take in two, three weeks in the fall.” You see, so they are doing that. Now they have to estimate the removal. I think that’s a good idea because there are practical things. That’s an argument I have with my friends from nitrogen, and I shouldn’t say this, but all of the, “Yeah, we should apply in the spring. We should apply in the spring.” “Okay, yeah. What happen if you cannot apply? And then in the fall, if you apply late and the soil is not too hot, you can apply.” Because these practical things and the logistics often are more important than the basic science that we are talking about.
Mike Howell (18:51):
Well, Dr. Mallarino, you’ve touched on something a couple of times during these podcasts. If y’all will bear with me, I think we need to run this rabbit just a little bit. We have talked a lot on the dirt about soil pH. We’ve done several episodes about pH. Alan think we’ve done what, three or four episodes of the two of us talking about soil pH. Dr. Mallarino, we went through a spell there that everybody that was on The Dirt talked about pH. I think it’s so important, but I still don’t think that message gets out. I hear growers all the time, “Well, I can’t afford lime. I can’t make these lime applications.” My response to that is, “You can’t afford anything if you can’t afford those lime applications.” Take just a few minutes and talk about the importance of soil pH and why we need to make sure we have our pH aligned.
Dr. Antonio Mallarino (19:33):
People often forget that we have very fast acidification of soils in Iowa, Illinois, southern Minnesota, because the nitrogen that we are applying. When you apply urea, you apply hydrosummonia, all these things, that acidifies the soil. So we cannot just sit down and say, “Oh yeah, these are pretty soils. They’re great. They used to have pH six to seven, blah blah, blah.” Yeah, that’s without nitrogen application. You need to be careful, okay? So it’s not necessary that you take soil samples and analyze the sample for lime requirement every two years, every year, but every four years you should do that. So that’s another thing that we had lots of long-term experiments in Iowa since the ’60s, but there were point experiments. There were two, three experiments long-term. We did not have on-farm research really to prove a things.
(20:31)
So I’ve done lots of on-farm research, again also with the help of the Iowa Soil Association, the Limestone Association of Iowa and other people, lots of research. And I have confirmed you don’t need to have pH 7, but you cannot afford to have pH less than six for corn and soybean. I mean, you need to look at the prices, yes, you need to look at the cost by ECC, that’s the effective calcium carbonate equivalent of the limestone, and then apply based on that and then try to avoid this very low pH that we have problems.
(21:11)
Most farmers and consultants have this in mind, “Oh yeah, pH, yeah, we need to be careful, alfalfa and soybean, because it’s a legume and the nitrogen mixation and so forth.” Oh yeah, the most consistent and higher proportional responses I found to liming is corn. It’s just amazing. I have published that, it is in many publications. It’s in the Iowa State Extension Soil Fertility website. They can look at that.
(21:39)
See, once in a while I get pH 4.9, 4.8. This is ridiculous. Okay, what I’m hoping is that those were fields that were CRP or they were patches or something that now are into production. They cannot afford that. They may be losing 50, 60 bushes of corn. I mean, it’s amazing. So people need to do that. What are the situations that they should watch more? Continuous corn, because continuous corn you apply nitrogen every year or you apply manure every year. And in those situations, you cannot afford not testing for pH every four years or so. You need to apply lime.
(22:23)
So yes, I think it’s important, and people don’t pay attention to that. See, I bet if the corn state about 3.50 or things like that and the soybean at $9 or less, the first thing that they will not apply this fault is lime. That’s the first thing. Now, some farmers are applying all kind of microdune, just that they’re not needed. I have done hundreds of experiments in Iowa. So they spend money on that, but they don’t apply lime. Come on. So yes, lime is important. Not necessarily you need to get to pH seven because some salesmen out there rock the boat, “Oh yeah, we need to have pH 6.9, 7.” Yeah, maybe for alfalfa, for highly production of alfalfa, but not for corn or soy.
Mike Howell (23:12):
Alan, I know you always have a lot of comments about pH. Anything you want to add to the pH discussion?
Dr. Alan Blaylock (23:18):
A few comments on that, Mike. When we talk about pH, we’re talking about a very basic soil property. And pH influence so many things in the soil, and we have these days a lot of discussion about soil health. And so keeping in mind that soil pH affects all of these soil organisms, the bacteria and the fungi that are in the soil, it affects nutrient availability, it can affect root growth. When we these very acidic pHs that Antonio’s talking about, we start to inhibit root growth. And we inhibit root growth, what does that mean? That means that that plant is going to have access to a smaller soil volume, it’s going to be less able to take up water, it’s going to be less able to take up nutrients. And so we have some very direct effects of pH on plants, but we also have some indirect effects.
(24:09)
The little story from my Iowa State days, from my PhD final written exam, we have to pick some different things to write about. At least it was in those days. One of the questions that I had to answer was, if you could measure just one soil property, what would you measure? And then explain why. Well, I had picked soil pH. I thought, “If I can only measure one thing, I want to know what that is.” And then I had to explain why, and so talking about all these interactions. And so pH can, again, directly affect a number of these things that affect the farmer’s yield and therefore his profitability. So it’s an investment the farmer needs to make.
(24:51)
Now, I do want to make a couple comments about soil testing. We’ve talked a lot about soil testing here for P and K, and now for pH. Soil testing is one of the farmer’s great tools. It’s really pretty inexpensive compared to all the investments he’s making. Whatever the price of that sample is, $50 a sample or $60 a sample or maybe if he’s doing a real complete test, maybe $100 a sample, that’s a really small amount compared to what he’s going to spend on fertilizer and all the other things that go into that crop. Do that. Do your soil testing. It’s not perfect, as we’ve talked about, but there’s a great deal of information there. A farmer can then take that information, interpret that in the context of all of the other aspects of his crop management plan and say, “What does this relate to my logistics, my timing, and all these other things we’ve talked about?” But that soil test is a starting point of all of those decisions. You have to have that good information.
(25:51)
Not every year, but you need to be collecting that information, and sometimes the trends over time are more important than an absolute value. Is my P declining? Is it staying the same? Is it increasing? Same with potassium. What’s happening to my pH? Is it increasing, decreasing, staying the same? The trends over time can really be important. So maybe testing every four years is adequate or every other year, but particularly if you’re seeing changes from year to year or over a period of time, then maybe you want to sample more frequently. But it is a very basic piece of information that the farmer should not be neglecting, and particularly in terms of the return on that investment, it’s an inexpensive tool and it’s a starting point for so many decisions.
Mike Howell (26:37):
Okay, well, let’s get back and finish our discussion on P and K. That’s what we wanted to talk about. Dr. Mallarino, we’ve talked a lot about P and K. One thing we haven’t talked about is how much of these nutrients a plant needs. So if you would take just a minute and go through the P and K recommendations for corn and soybeans, how much are these crops going to be needing?
Dr. Antonio Mallarino (26:58):
Okay, as I said, we updated that last year. Our criteria for the recommendations for the low testing categories is… Well, I have the publication somewhere. I’m getting old, you see, I don’t remember some numbers. But for example, for corn in the very low range, we recommend 120 pounds of P205 per acre. For soybean, it is a bit less, it’s about 80. Those are the rates that we put in there. They’re not related to yield, because as I said, those are rates to get maximum yield in different conditions you get 200 bushes or 300. But of course, the residual effect of those applications and how much you build up depends on the yield. That’s why for the maintenance in the optimum, we have some recommendation, we have some yields there as a default because the lab says that not all farmers give them the prevailing yield level to calculate the removal. So believe now we have 210 bushels. I think it was 180.
(28:12)
So we say so many ways in our publication, every time I speak that farmers should use for the maintenance their own yield estimate, not the yield goal. You see, yield goal, I wish that word would disappear of the language because that doesn’t work on nitrogen and it doesn’t work at all for P and K. So it is the prevailing yield that they should put there. And that’s what many people are not doing or not looking at that for the removal. Then of course, alfalfa harvested for hay, that’s incredible. The removal can be [inaudible 00:28:49] because you can get, I don’t know, two tons per acre of hay, you can get eight. So people need to watch that because that removal is important.
(28:57)
Another thing is that since a few years ago people started bailing corn stalks or ethanol or for bedding or things like that. Look what you are harvesting. Hey, as I said, phosphorus, if you harvest corn and then switch to silage or harvesting corn stalks, phosphorus, you increase the removal by about a third or something like that. Why? Because most of the phosphorus in corn goes to the grain. But if you are in potassium above two-thirds, three quarters of the potassium stay in the stalk, little goes to the grain. So you are harvesting grain, you may need 50 pounds to apply remover, but if you are taking silage, I mean you may need 100, 150. And many farmers are not looking into that. So they need to understand that that has been part of our rotations. So I guess those are the important things that I would say.
Mike Howell (29:57):
We run into a similar situation. I mentioned that I was the peanut specialist at one time down in Mississippi. We do a cotton and peanut rotation and everybody will fertilize for the cotton. The peanuts are a great scavenger of nutrients and I usually don’t make a lot of fertilizer applications in the peanuts. But a lot of these guys are harvesting that peanut straw for hay. We won’t get into that today, but they’re removing all of those nutrients that are in that peanut straw when they do that. They don’t soil sample after the peanut crop, they just assume that everything’s still there. We’re seeing a lot of deficiencies in those peanuts because they’re removing everything. So Alan, I know you’re an expert in potato production and we’re going out to a lot of listeners here, any comments about potatoes and P and K use?
Dr. Alan Blaylock (30:38):
Potatoes are a fascinating crop, Mike. Most of my entire life has been spent in potato-producing areas outside of the years I was at Iowa State here in Iowa, kind of got dissociated with it, but we had potatoes on our farm at home and lots of potato growers around us. Potatoes are a bit more challenging in a way, and a lot of that challenge is related to the root architecture of potatoes. We have a very shallow rooted system. Most of the nutrient uptake in potatoes occurs within the top, say, three to four inches of that hill. They don’t have a lot of deep roots like corn. We can mine a lot of that soil profile. There’s a lot of nutrients in the subsoil that corn can use. We don’t have that with potatoes.
(31:23)
Also, sort of related to that, is that potatoes have very high P and K requirements. And so when we look at some of these potato growers in Pacific Northwest in the Columbia Basin where they’re growing tremendous potato yields, hundred weight per acre sometimes in some of these potatoes, and potatoes, when you harvest that tuber, the potato itself, you remove a lot of potassium. So some of those growers are applying five or 600 pounds of K2O per acre on some of those high yielding crops. In phosphorus, potatoes generally need a quite a bit higher soil test level of phosphorus, maybe double what corn needs or more. So it’s particularly challenging to maintain those high levels in a very shallow root zone and make sure we’re getting enough to the crop to maximize yield but also quality because both P and K have influence on the quality of the tuber itself.
(32:24)
So it’s quite a bit more challenging, it’s more complex. Sometimes they will run some phosphorus like a 1034 solution through a pivot or something like that. In season they’ll watch the petioles, which we call, it’s just the little stem to which the leaflets are attached, so they can test for phosphate concentration in those petioles and make some in-season adjustments. So they will do that occasionally through their irrigation system. Not so much with potassium, it’s a little harder to do. But both of these nutrients are really critical to potato production. And potato crops, as I’ve said, are more challenging and need higher levels of those nutrients to maintain good plant health and good tuber quality.
Mike Howell (33:08):
We’ve spent a lot of time talking about the fall application, and a lot of times tillage goes along with that. Do we need to worry about tillage when we’re making these applications? Do we need to make the fertilizer application before the tillage operation or does it really matter? Dr. Mallarino, you want to start off on that one?
Dr. Antonio Mallarino (33:24):
Yes, it’s important, and our recommendation is that those that do tillage in the fall to apply the P and the K before the tillage. That’s another one I mentioned, I believe, before. Everybody’s nervous trying to take soil samples and apply fertilizers because of that. They want to do the tillage before snow, you see? But for example, in soybean, we do not recommend tillage in the fall in Iowa. And of course, in no-till there is no tillage.
(33:52)
The issue there is that some people believe that broadcast phosphorus application in the fall on soybean residue, that’s a big problem for phosphorus loss and water quality. That’s another thing that I work a lot. That’s another thing when I say, “Hey, be careful when you listen to what the wind brings for the east or the northeast, those are completely different conditions. We are in Iowa.”
(34:20)
Because normally what happens is that when we apply the P and the K on soybean ground in the fall, in some part of the country there is lots of rainfall in the fall or liquid rain in the winter, no snow. The losses could be important there. But that’s why it is very important that we recommend that they put the broadcast P in the fall before snow and before soils freeze, because that will make the phosphorus, the fertilizer, the manure react with the soil even if it is on the surface. We don’t get much snow in Iowa. It’s not like in Wisconsin, Ontario and all those states, Northern Ohio. So when it comes the spring after four or five months, that phosphorus is retained.
(35:05)
So actually it’s much more dangerous in Iowa to apply broadcast phosphorus for no-till in the spring, because if you apply that in the first second week of April and then you get four inches of rain, all that, goodbye, go to New Orleans and Mississippi. So these are things that are very important.
(35:24)
I’d like to say something else. Many farmers apply the two-year rate for the corn-soybean rotation before corn in the fall. It’s amazing because people from Iowa State before me in the ’60s and in the ’70s they show that when they apply the two-year rate, it doesn’t matter if you apply before corn or before soybean. But everybody for some reason had this idea the soybean doesn’t respond as much as corn, so they apply before the corn and then good luck to the soybean next year. But if they apply the needed rate, that can be applied in the fall on corn residue, not on soybean.
(36:08)
Now, when I started saying that about 15 years ago here in Iowa, everybody look at me like I was crazy. More people in Iowa are maintaining twice the levels of phosphorus that we recommend. They’re maintaining high levels. So why are going to apply a high rate, the two-year rate of phosphorus on soybean ground when you have these slopes that goes to the river with rain? So apply that two-year rate on corn residue in the fall because then there is not much erosion or much losses there. And then if you put sufficient pounds, you have that for the corn next year. What is the answer I get? “Yeah, that’s great, especially for no tillers because they love applying things on corn residue because there’s much less compaction than on soybean residue.”
(36:58)
But what about we put MAP. So we are wasting all that nitrogen to the soybean. And this is something that I have been arguing with my friends from the fertilizer industry for 20 years, from Paul Fixon to all these big guys, Kim Polisoro, Alan Blaylock, all those guys, “Why you do not make triple super phosphate in the United States?” And then sometimes people from NRCS is getting upset about that. So they need to import the triple super phosphate, and then when you look at the prices, it’s cheaper to DAP.
(37:40)
But I mean, come on, MAP is not a big deal. But with DAP that has 18, 20% nitrogen, if you are applying that nitrogen to alfalfa, you are applying nitrogen that, dammit, is not needed. Now, it’s not a big deal because in alfalfa there’s not much losses, things like that. But if they apply to soybean, they’re applying the nitrogen. Now, if you apply a removal rate annual, say, 40, 50, 60 pounds of P2O5, that amount of nitrogen that you apply is not a big deal and actually in some cases may be good for soybean. But when you applying it to your rate, that’s a problem, and that’s one of the things that I wish my friends from the industry will think about that.
(38:26)
I know there is the logistics and all these things, I understand that, but there was a major co-op in the north central region that they started importing triple superphosphate and they started. Then of course, the dealers complained because they have to have different beans, all kind of things, but that’s one problem. And so if you have sloping ground and really you are in no-till, you are not incorporating in the fall, maybe it’s a good idea to apply the annual rate, not to apply the two-year rate on soybean ground because you may get losses.
Mike Howell (39:01):
Well, I’ve got one final question, and I know we’re going a little long again this week and they’re over here telling me we’ve got to hurry up because we’re going to run out of space on the recording. That just doesn’t happen when I’m in my office doing this, but things are a little different when you do it live. But we’re going to wrap this up with a final question, and I’ll give both of you a chance to answer this. We hear a lot about enhanced efficiency fertilizers these days, and most of the time we associate that with nitrogen. But walking around the showgrounds here, you can see people talking about enhanced efficiency options for P and K. I’m not really familiar with a lot of these things that are out here, so Dr. Mallarino, you’ve been working on this for a long time, tell us what your research shows. I’m not going to get you to name anything if you don’t want to put out a specific name or anything like that, but are there products out there that can improve the efficiency of P and K?
Dr. Antonio Mallarino (39:48):
I have not worked a lot on these products, because for phosphorus and potassium, really there were not many until 2, 3, 4 years ago. Now we have all these biologicals, all that stuff. The thing with some of those products, first, some just don’t work. There have been recent in other states like in Minnesota and other places that they don’t work. So the other thing is the cost money. So the farmer that is trying to use those need to cut the normal fertilizer rate, and then that thing doesn’t work, then we have a problem. The other thing is that especially in the case of phosphorus, we have fertilizers that have soluble P in water. We don’t have fixation here, we have retention, which is good in our soil, it’s not bad. So you put something that makes that phosphorus even more available or more soluble or that blocks the retention by the soil, you will be increasing losses of phosphorus there. So it could have that issue.
(41:00)
Now, if it’s true that they work and then you reduce the rate, yeah, it may compensate. I believe that those products, I’m not talking about nitrogen, okay, I’m talking about phosphorus, potassium, it’s not really guaranteed that they will work in our conditions. And also because our soils and all the things that we were talking before and in the previous session, is that farmers don’t like to cut the fertilizer rates. They don’t want to risk yield losses. About three quarters of the fields in Iowa, they’re maintaining and they’re maintaining high levels. So what would a more efficient fertilizer will do there?
(41:45)
I did work with a project for two years looking at some new coating for fertilizer, phosphorus, things like that, and it worked great, but then they realized that at least here, the market is not for that. That was never released. But I believe that especially for people that are a bit extreme in sustainability and really want to apply less nutrients and less chemicals and things like that, there needs to be more research in all these biologics. In fact, part of the reason that I never work on that is because when a company or two ask me to work on that, I say, “Listen, I’m not going to do a trial or two and I’m going to just measure yield.” A graduate student half-time is $35,000, so I need funding. So we measure yield, but we also measure soil things, we measure micro electivity, we measure uptake in different part of the season. We need to do this, not just put a couple of strips and try. That’s the main reason that I never work on that. So that’s my view. I believe that in some conditions for some people that they really prefer to cut chemicals, quote, that maybe some of these products could work.
Mike Howell (43:05):
Alan, any thoughts on this?
Dr. Alan Blaylock (43:07):
Yes, Mike. So yes, there are a number of new products that have been introduced and really we’re seeing a lot more movement in this area in the last four or five years with a number of new products. There’s talk about phosphorus-solubilizing bacteria, organisms that particularly make residual soil P more available. Maybe there’s some promise there. There are chemical treatments to, as Antonio mentioned, enhance phosphorus solubility that maybe would improve the availability of the fertilizer. There’s a variety of these kinds of treatments that have been introduced in into market.
(43:42)
Now, agree with Antonio on several things here. First of all, a lot of these things don’t yet have a body of research we can go to that prove the efficacy and where they work and maybe where they don’t produce a benefit. We need to understand not only where we get the benefit but where we don’t get the benefit, that’s part of that value equation. We just don’t have that research body yet for really any of these products that I have seen.
(44:09)
The other thing is we want to be very careful about the site specificity of these products because we have this variability, and there are cases where they may really provide a benefit, let’s say we have a soil has really high P-fixing capacity, not the retention Antonio is talking about, but really making P unavailable, if there’s something that could offset that and keep that more available, then there’s a realistic probability that maybe there could be a benefit. So again, as I said about the fertilizers themselves, very site-specific. Understand what your situation is. Does it make sense that a product would have a benefit or not? Look at all of those things. Consult with an agronomist, consult with your Extension people. What research has been done on the product? Is there documentation of a clear benefit there? And understand the probability of getting that benefit because a lot of these things are pretty inconsistent. Maybe a big benefit here and nothing over here and sometimes maybe even an opposite effect and undesirable effect.
(45:12)
So what can the farmer do? Best advice I can give the farmer on this is to do a trial on your own farm under your conditions. I don’t mean one field versus another or even split a field in half. I mean, do a legitimate trial where you have some replicated strips, you can measure the yield with your yield monitor on the combine, but replicate that across the field. Do a test that you actually know that you’ve got a meaningful result and you can look at that and say, “Okay, I’ve got a difference or I don’t.” There’s all kinds of helps online and with the Extension people on how to do those trials, but replicate those strips across a field, or better yet, multiple fields over multiple years and know whether it works in your field under your conditions with your soil types and your weather, and then you can make an educated decision.
(46:01)
There’s lots of marketing hype around all kinds of biological products in the market these days. I don’t necessarily want to take all of those at their word. I want to test it. If I’m a farmer, I want to test it on my farm under my conditions and get an answer for myself just because I’m a skeptic on a lot of things. It’s just my nature. But a farmer can test that for himself and get an answer. And so that’s the best advice I could give because we don’t have this body of research, as I said, to look back on, and these are highly variable. Put those 4R practices to work in the same way that we would for fertilizer, right rate, right time, right place, right source. Understand those because there are lots and lots of choices out there and a farmer can become very bewildered with being confronted with all these different products.
(46:45)
Pick something that makes sense, put it to the test on your farm, take that answer to help in that purchasing decision. But it costs you money, and when you start reducing fertilizer rates, you start running the risk yield loss or loss of soil fertility, so make sure that it’s going to do what they say it’s going to do. That’s the advice I would give to farmers in that regard because this is pretty new arena. We have a long history of nitrogen products that enhance efficiency and we know how they work and we know where they work and what benefits they provided. We sell some of those, and we have a body of research to back that up, but a lot of these phosphorus products are still pretty new to the market and we just don’t know very much about them. So that’s the advice I would give to a farmer.
Mike Howell (47:26):
Alan, great advice. Gentlemen, I want to thank you again for being my guest here on the show. I think we’ve had a really great two episodes out of this. Couldn’t have done it without you.
(47:35)
Listeners, we appreciate you tuning in to this edition of The Dirt. Want to invite you to hang around for just a moment as we get ready and bring you segment two here in just a couple of minutes.
(47:44)
Listeners, I hope you enjoyed the first segment of today’s show. If you did, please take a minute and give us a rating on your favorite podcast channel or app and give us some feedback as well. We want to hear from you to help make the show even better. And don’t keep it to yourself, please share these episodes with coworkers, family, friends, anyone you think may benefit from the information we’re sharing here. Don’t forget to visit our website, nutrien-ekonomics, with a K, .com to help find the latest crop nutrition news and research information as well as market updates, a growing degree day calculator, a nutrient use calculator, a rainfall tracker, and much, much more. It’s all at nutrient-ekonomics, with a K, .com.
(48:29)
Most episodes of The Dirt are now available for CCA credits. Visit our website and click on the Agronomics tab to find these CCA credit opportunities. And if you have a question, you can ask one of our agronomy team members. Simply ask your question and one of us will get back with you. Thanks for listening. Now, segment two of The Dirt.
(48:52)
Well listeners, welcome back for Segment two of The Dirt. We’re continuing our tour around North America looking at different research farms. Today we’re going to be visiting the state of Missouri, and we have Dr. Kelly Nelson with the University of Missouri with us. Kelly, welcome to The Dirt.
Dr. Kelly Nelson (49:07):
Thank you, Mike. Great to be here.
Mike Howell (49:09):
Kelly, if you will, take just a few minutes and introduce yourself to our listeners and let them know what you do there with the University of Missouri.
Dr. Kelly Nelson (49:15):
Sure, Mike. I’m Kelly Nelson. I’m Agronomy Professor in the division of Plant Sciences and Technology. I’ve been with the University of Missouri for about 26 years, and I’m part of the Northern Missouri Research Education and Extension Center.
Mike Howell (49:33):
Kelly, I know you’re based on one of the research farms there. Tell us a little bit about the research farm, the name of the research farm, and a little bit about the history.
Dr. Kelly Nelson (49:41):
We recently went through a little restructure a few years ago. I’m based out of the Greenley Research Center. It’s called the Lee Greenley Memorial Research Center. It’s now the Lee Greenley Memorial Research Farm, which is under the umbrella of the Northern Missouri Research Extension and Education Center. So that entails about five farms and about 4,200 acres dedicated to not only crops but forages and crop and beef cattle research as well. The research farm here was established in 1969. It was dedicated in 1974. We’ve hosted about 47 Field Days since it was established.
Mike Howell (50:30):
Well, that means it’s one of the newer research farms around, only about 50 years old, but still a very important research farm. I know we’ve done a lot of work out there and been out to that farm many times over the years. I’m always impressed. Kelly, I was there probably a month or so ago visiting some of your research plots. One thing I’ve noticed is in the last couple of years you’re putting up new buildings and making a lot of changes around the farm. Tell everybody a little bit about some of the changes that are happening.
Dr. Kelly Nelson (50:56):
I think that growth is one of the important parts of where we’re headed. The trajectory is pretty amazing too. We’ve added additional faculty, and with that you need the facilities to accommodate them at the same time. We’ve added a forage agronomist with the Cornette Farm. His name is Dr. Carson Roberts. Dr. Gurbir Singh we’ve added as a hydrology agroecology and landscape management focus here at the Greenley Farm, and then Dr. Gurpreet Kaur as a soil scientist on site here at the farm as well. We’ve added a lab, a water lab, a tissue processing facility. We’ve added another tissue lab over at the Cornette Farm. It’s been an exciting time to see that growth that’s taking place.
Mike Howell (51:42):
Well, Kelly, if you will, tell us a little bit about some of the work that goes on out at the farm. What types of research are you working on on a daily basis?
Dr. Kelly Nelson (51:49):
We have about 100 projects directly managed by faculty on site. I think there’s about 130 projects when you include campus-based faculty on site as well. We have a very diversified portfolio of research, including crop protection, but also water management, fertilizer management, as well as grazing systems and so on and so forth there. There’s a lot of focus on conservation and how do we maintain our stewardship but enhance our productivity and profitability at the same time.
Mike Howell (52:25):
Kelly, one of the things I’m asking a lot of people about is some of the most significant findings that’s going on at the research farm. I know these farms, no matter how big or small, there’s always a lot of important research, relevant research that’s going on, and a lot of discoveries have been made at these farms over the years. Take a few minutes and talk about some of the things that have happened there at the Lee Greenley Research Farm.
Dr. Kelly Nelson (52:45):
One of their big highlights has been some of our drainage water recycling work. We started some drainage and sub-irrigation work back in the early 2000s. We’ve always had a conservation focus. In 2014, Ms. Greenley passed away and she gave us a 240 acre farm just south of us. We really focused on making that into a conservation showcase. Basically new technology on a farm scale level that allows us to demonstrate new technology. One thing I’m really proud of is our variable source agrochemical application technology that was developed here. A lot of that focused on enhanced efficiency fertilizer, but we’re basically changing sources as we move over the landscape. We have a very diversified landscape. As you were driving through the area, your stomach churns a little bit and it kind of feels like a roller coaster. And so with that diversity brings a lot of opportunities for us to put technology in certain areas or certain landscapes so that we can, again, enhance that productivity and our profitability on that ground as well.
(54:00)
There’s also been a lot of work done on management intensive grazing systems. We have a long history of that research in the experiment station here in Northern Missouri, and there’s a lot of leadership when it comes to artificial insemination technology as well. So it covers the gamut of crops, livestock, and we work with a lot of new technology. I’d say identifying the fit of that technology for the challenging conditions or soil types that are specific for any given area is very important for the experiment stations to address the local concerns and local challenges that farmers face in those areas. You’re always working on some new technology. I’ve had some that we’ve been working on for 10 years and I don’t think it’ll get released for another five years. So I can’t disclose that one yet, but it’s exciting on where it’s heading. And again, it’s just so great to work with that new technology when you can look back and say, “Hey, that nitrification inhibitor, we worked on it for 10 years and now it’s on the market and it’s doing great things.”
Mike Howell (55:14):
Well, Kelly, we really appreciate all the work that’s coming out of the farm there. We have spent a lot of time and effort out there, and we’ve got a lot of good information through your research in the past and hope to continue that relationship. One thing that I’m asking all of my guests this year is, we know that agriculture is changing. There’s a lot of new technology coming out. You’ve mentioned some of the technology y’all are working on. We also have more and more people in the world. People have to have places to live, and they’re encroaching on our farmland and farmers are going to have to change the way they do business in order to keep up with this. But to keep our research farms relevant, we’re going to have to change our research farms to keep up with the pace of agriculture. How do you see the research farms changing over the next 50 years to keep pace with the ever-changing world of agriculture?
Dr. Kelly Nelson (55:59):
I think one of the things, when you stepped on, you saw a lot of equipment. One of the key things has been to enhance our efficiency from not only a research but a productivity point of view. Our cropping systems, our farms are getting larger, and we’ve got to be more efficient with what we have and use the technology that’s at our disposal to make our farms more profitable, but yet enhance the productivity at the same time too. At the end of the day, we do have a growing population that has one thing common, they always have to eat. We’ve got to make sure that we have a stable food supply, that we’re working on resilient cropping systems so that we have that consistent productivity year-in and year-out and try to address a lot of that variability that we see from year to year that can stabilize and maintain a good supply of high quality food each year.
Mike Howell (57:04):
Well, Kelly, we really appreciate you taking a few minutes to visit with us today and talk about the Lee Greenley Research Farm there in Missouri. Listeners, we appreciate you tuning in this week. And as always, if you need more information on anything we’ve talked about today, you can visit our website. That’s nutrien-ekonomics, with a K, .com. Until next time, this has been Mike Howell with The Dirt.
