Today on Topcon Talks Agriculture, we chat with Dr. Kendall Kirk and Alex Coleman from Clemson University about management zones, the creation of management zones, and the proper application through variable rate.
Today on Topcon Talks Agriculture, we chat with Dr. Kendall Kirk and Alex Coleman from Clemson University about management zones, the creation of management zones, and the proper application through variable rate.
Hello, and welcome to another edition of Topcon talks ag. My name is Dave Warren. I'm the regional sales manager for Canada. Today. We have a very interesting topic of management zones, the creation of management zones and the proper application through variable rate. To help me talk about this topic today from Clemson university, we are joined by Dr. Kendall Kirk, who is the precision agriculture engineer, and then also Alex Coleman, who is the extension, small grains and soy room specialist. Thank you guys very much for joining us today.
Speaker 2:Thanks for having us appreciate the opportunity.
Speaker 3:Yes, thanks for having me guys,
Speaker 1:Dr. Kendall, I'll start with you. What exactly is a precision agriculture engineer and what all does that entail in the, the daily life?
Speaker 2:My wife asked me the same thing, and I think it's a different answer every time. Precision ag, you know, means a lot of different things in a lot of different places and ultimately it revolves around the needs of the farmers in your region. Uh, so I think initially precision ag focused on a lot of what we, we came here to talk about today, variable rate application, but it's become more than just that it's become image analysis. It's become sensors and automation, big data management. So that's where, uh, where I say my answer to the questions often a little bit different. Um, there are many things that it entails and, and it spans all crops and livestock alike.
Speaker 1:Wonderful. And at the university of Clemson, are you in the classroom or, or mostly on the research side of things?
Speaker 2:I worked in the classroom for about a decade teaching in our agricultural mechanization and business program. It's an ag engineering technology program. Uh, and then in 2014. So I guess, uh, eight years ago, I, I came to one of our research and education centers and that's when I began as a precision ag engineer just recently, I've been asked to, to lead up an effort to create a center for agricultural technology at Clemson. So that's a brand new thing that we're starting off this year
Speaker 1:In future episodes. Maybe we'll have to get back to you and, and get a, you know, update on how that's going and what all that entails. Cause that's a very interesting topic. Also
Speaker 2:Love to do that.
Speaker 1:Now, Alex could, uh, you just walk us through what your daily, uh, work at Clemson entails and, and how it relates to, uh, what we're gonna talk to today.
Speaker 3:So I'm an extension, small grain and so specialists. So I deal with any issues that farmers of South Carolina have relating to those crops. Also do research trials on various topics to do with those crops and, uh, try to promote them to the growers of South Carolina as well. I did a lot of research in my master's degree, work with zone sampling and grid sampling and different methods to develop them and comparing those methods and seeing which ones put more money back into the grower's pocket. Um, so look forward to using that experience and getting it out to the growers who can use it.
Speaker 1:So it sounds like you obviously are a lot more involved, um, with end users, producers alike in, in South Carolina, where maybe Dr. Kendall is a little bit more involved with the academia side of things, which really leads us to a nice mix of, you know, daily interactions moving forward for this cast. You know, I know that we're gonna talk a lot about zone sampling and grid sampling and zone management. What, what is the main concept and principles that you guys are looking for in working off of, in your research and, and studies and, and, uh, you know, the way that you portray it through documentations?
Speaker 3:So the, the main thing that we look to do is benefit the farmer, whether that's saving them money, making them extra money that I normally wouldn't have gotten, or helping them preserve the environment that they have to depend on every year to grow their crops. And so one of the, the major ways we do that is by, uh, different soil sampling methods and grid sampling being probably the easiest and most systematic one is where you just divide the field up into different equal area squares or grids across the entire field. And you would take a sample from each one of those grids zone management. On the other hand is where you use some form of discrete measurement, meaning a, a continuous measurement of something across that field to make a map of it, whether that's elevation or N D V or even, uh, yield data that you have from previous years. So something continuous that you can measure across that field and make a map from that.
Speaker 1:Interesting. And so then in a situation let's just take, uh, grid sampling and, and the soil sampling portion of it. How often would one have to do that and give us an indication of how often something along those lines is needed compared to zone management, we're working with sensors, you should be able to collect that a lot more readily available.
Speaker 2:So oftentimes what, what we suggest is that if we're using soil based zone management practices, the, the soil types really don't fundamentally change that rapidly with time, right? So when you have an area of generally heavier soils or, or generally lighter soil such as CORs or Sandy or textured soils, uh, those are generally gonna be the same areas today as they are 10 years from now, 20 years from now, the only thing that really changes that is, is conceivably some buildup and organic matter, or otherwise some erosion in the field erosive activity in the field, uh, that might move soils from one area to another. So aside from, you know, major grading that takes place in a field, usually if you've got a decent zone map, that's representative of dividing the field into separate management areas, that pretty well stays the same. Now, one thing that Alex learned in, in his graduate work was that the more yield data we have, the better job we can do at making management zones, if yield data is what we're using to build those zones. You know, at some point there's diminishing returns in that, but, but he learned that for instance, two years of yield data was better than one at making a, a yield management zone map.
Speaker 3:I was just gonna add that that's correct. And you know, one of the downsides of that is that obtaining several years of yield data takes several years, but also compared using yield data from different crops. So for example, if I had cotton in my field this year and I was plant corn in it next year, would my cotton yield data associate to my corn yield data that I could expect? And what I found was with one year of yield data, probably not wise to do that, but if you have several years where you kind of take into account the temporal variability the year to year variation in the weather and environment, then it does correlate better.
Speaker 1:So now Alex, as a follow up on that statement, can you, you know, year over year or multi-years use a lot of different crops or does it have to be a similar style of crop? And then secondly, that sounds like a pretty daunting task for probably a lot of our end users listening or our producers listening. Um, is that something that, you know, a local agronomist should be able to utilize this type of scientific methods?
Speaker 3:Yes, I believe so. What you really do to create a, we call it a composite yield map. Yield map of multiple years is really assign an average yield to the field. So the average area would be one and anything above average would be higher than one. And below average would be lower than one. And so you can, that puts all of the years of yield data on the same playing field, and you can combine them all to do that. So it's the process of putting them into a composite is not that complicated as far as the different crops. Um, I looked at basically farmers in our area grow corn soybeans, cotton. So cotton peanuts and wheated. And so basically I had a mix of all of those put together. That's what went into my, I called it my cross crop composite yield maps.
Speaker 1:That's very interesting. I know that, uh, we were talking offline a little bit here that in north America, we have a lot of different crops and a lot of different farming practices and no two regions are the same. You know, myself based up here in Canada has a lot of different crops and, and soils than probably you guys see down at, in, in the Georgia territory. But I think at the end of the day, a lot of the science behind it is similar. And a lot of the way of executing is similar and something that I'm appreciating for our conversation so far is that we've actually started a variable rate conversation off with data collecting and in collecting the correct information that leads us to variable rate in the precision agriculture industry. And I hope you guys can comment on this. Um, we see a lot of variable rating done without the quantitative data from the results of either variable rate in the year before or something that leads us to it. A lot of times we take maybe one that a topography or something along those lines of waterways and make a first version of a variable rate. And then we, aren't doing a great job of collecting data. You know, whether it is the yield data or moisture data, following it, um, to continue to elevate and evolve that variable rate. Would you guys agree with that and in what you've seen in the industry as a whole
Speaker 2:Yes, without question,<laugh> a lot of times, you know, people, they, they make their maps and those are the maps they're gonna go with. Oftentimes we see where, uh, consultants are a really important piece of this too. Oftentimes our farmers, uh, maybe they don't have the time they're, they're stretched thin as it is. And to have the time to negotiate the steep learning curve, to learn how to build variable rate prescription maps, or learn how to build the zones. Oftentimes it makes a lot of sense to bring in a consultant to help them with that. But often what we see is that the zone maps that they use the first year, they started variable rate applications are the same zone maps that they're using 10 years down the road. And, you know, I, we did say that oftentimes if it's a soil based zone map, well, that's probably okay. But as Alex mentioned, and, and as he learned in his project, the yield based maps on the irrigated land did better. And that, that was an interesting finding. When we looked at non irrigated land in his study, the soil based maps did a better job of, of dividing the field into zones where you're maximizing the differences between the zones, but minimizing the differences within the zones, going back and, and, you know, the yield monitor is an amazing tool and it, it gives the farmer, the ability on their land to test, what would it have looked like if I did it this way versus had I done it that way, that's not something we can do on an experiment station. That's not something that, you know, 10 miles or even five miles up the road that the research and education center can do because it's not the same ground. It's not the same crop history, not the same management practices. So we, we do our best to encourage growers to take these big questions they have, you know, should I be grid sampling, should I be zone sampling? And they can have some strips out there in their field where they do it both ways and evaluate what, what did best
Speaker 1:When I'm working with a customer or a dealership with the customer. I always like it to, you know, if you break your arm, when they go to remove the cast, they're probably gonna x-ray again to see if it's healed. Um, and sometimes we need to make sure that we're collecting all that data to make sure that what we did is working and, and validate what we're doing. I think that's a, a huge step that we, we, as an industry can improve on. For sure. I guess when we get to looking at variable rate application, what information have you guys gained to believe that the ROI on a variable rate application is so great that it's something that we should really seriously all look at being adopting to
Speaker 3:In my research for my master's degree, I compared, uh, a little more than two dozen different ways to create these zones and grids. And without a doubt, doing any one of them was better than managing on a whole field basis or just putting one application right across the field. So I would tell a farmer that anything you do to try to divide this field is going to benefit you.
Speaker 2:I'll, I'll follow up to that in the same way that, you know, you provided an analogy on, on breaking your arm and x-ray, and after the cast comes off, I liken variable rate zone management, grid management, whichever it is I, I liken it to as I'm a instructor or, or was an instructor for more years than I've been doing what I'm doing now. It's, it's a lot like teaching, not every student in the class has the same needs. Not every student in the class receives information in the same way. And oftentimes you have to have different strategies for different students. It's the same way in your field. You got different yield potential. So that's gonna drive differences and needs for inputs or profitability of inputs, if nothing else. And then you've got different base levels. Um, the build on Alex's statement though, he learned what he learned, that any, anything we did to break a field into smaller management zones, whether even if it just be three divisions of a, of a hundred acre field, that was still better than uniform rate in the entire a hundred acre field. And, uh, a caveat to that is that was done with Alex. What year's fertilizer prices, do you remember?
Speaker 3:Um, pre pandemic around 2020, 2019.
Speaker 2:Yeah. So, you know, you, you look at that and you look at the current landscape we're in for fertilizer prices, commodity prices and technology prices. So fertilizer and commodity prices this year are as high as they've ever been, which means in the case of fertilizer prices, the cost of over application is higher than it is ever has ever been. And with the commodity prices, the cost of under application of fertilizer is as high as it has ever been, which would be, you know, it would equate to lost yield and therefore lost revenue in the field. At the same time, the general trend in technology prices in any sector of industry is that technology prices tend to go down with time. And so we are at a place right now where the ROI from variable rate application is as high as it has ever been. If a farmer looked into variable rate five to 10 years ago, and it didn't make sense for them, then I would encourage them to look back at it now because the, the factors have changed dramatically
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Speaker 1:Dr. Kirk, what would be the exact, you know, the hardest part, the biggest challenges, I guess you could call'em of getting into zone management or variable rating. If, if that is one of the hurdles that these guys are experiencing, and it's not about the ROI when they see the benefit of it, but it's rather the, you know, the hurdles, it could be, you know, retrofiting older machinery, or it could just be the fact that maybe they don't wanna adapt that on their farm, but what are some of the hurdles that you see getting into zone management and, uh, variable rating?
Speaker 2:I think most of the hurdles that we see and that, that we experience in communicating with farmers in our area is really centered around time investment and somewhat around apprehension, right? Because when you look at the complexity of variable rate application, uh, being able to interact with GIS tools, uh, having a tool to be able to know what zone you're in, in a field, when you collect the sample, having three to five times as many samples go to the soil test lab for a field, as you normally send to the lab, that's where I think starting slow is really important. This is something that Alex mentioned as well. You know, somebody that wants to explore variable rate applications should not try to do every field they have in the first year. They try to do it. They should pick one or two fields, maybe three or four fields with a high degree of variability partner up with a consultant in their area that can help them make the maps and, and work alongside that consultant. If their goal is to do it on their own down the road, they shouldn't dive into it head first right away. And they, they should have somebody be it, a consultant extension agent, somebody that can walk alongside them and, and help guide them through the practice. Maybe, maybe it's just go to their neighbor's farm when their neighbor's collecting their sample. Their neighbor maybe has been doing it five to 10 years. Hey, can I ride along with you while you collect your samples, help you out, uh, kinda learn how you integrate it with your maps to make your prescriptions.
Speaker 1:And so I guess that leads me to my next question of when is the proper time to kind of take on this endeavor? Obviously, you know, we're sitting here, it's the middle of the seeding season in, in my region in Western Canada. Um, and I believe planting is going on throughout the Midwest. Now, um, this isn't something that you tackled in the first week of may. I think it's probably something that you have to have a little bit more insight in. So when would be the appropriate time to kind of make this decision, sit down with, you know, the aforementioned agronomists or trusted advisors and decide how you're gonna proceed with this and start collecting this data.
Speaker 2:Well, first of all, practicing variable rate application is, is entirely dependent on how you sample. So it has to be done before you sample a field for a given year in South Carolina. The general recommendation is that we sample every field every year. And most of our large acreage producers do that. Um, we, we see pH soil pH can vary widely from year to year and, and we have to stay on top of if, if not other nutrients certainly have to stay on top of Lyme application from year to year. So the time to make a decision, what fields are you gonna go after this year? If you're going to just get into this, you've never done it before, make that decision in the summertime or, or during harvest be thinking about what fields you want to go for. Uh, and then the zones have to be developed before you sample. So you've gotta leave yourself enough time that prior to the time that you need to have your samples done, to get your first fertilizer application in for the year, depending on if you practice fall fertilization or, or spring fertilization, you've gotta leave time for somebody to build those maps for you or otherwise to, to get the maps constructed yourself, use those maps to, to sample the field. There's ways that, that we've got, uh, accessible to every farmer in, in the United States anyway, to get a map off of U S D a Sergo data, that's a common practice. We see it's kind of the easy button on getting a zone map, but one thing that we've learned and partly through Alex's research, those zone maps, don't always, or the maps, the SGO maps, the soil type maps. They don't always align really well with what the farmer actually sees as differences in productivity in the field. The reason for that is they were never created for variable rate management. They were created for sort of region level, uh, inventories of soils in, in the United States. So eights. So we, we, uh, don't necessarily discourage people from using them, uh, but we do encourage them to stand back and look at'em and see if they make sense. Some of those maps were made when they were still trees in the area. And, you know, the, the surveyors who built the maps, uh, had to, had to do a lot of guesswork in, in creating some of them.
Speaker 1:So then Alex, I guess the question for you would be, um, you know, we, we've talked about a few different forms of this, and I believe you said that there's up to a couple dozen of them, but we've talked more specifically about grid sampling and zone management for a person that's looking to just get into this and wants to focus, you know, kind of like Dr. Kirk said, along the lines of maybe just a couple or a few fields in your studies, have you found that one of these is more beneficial than the other, uh, by itself, or is one a little bit more conducive to the, the adoption of it to a farm that hasn't taken on these types of data collection and variable rate applications, yet,
Speaker 3:If you have existing yield data that, um, a lot of times we find that farmers have yield data and they look at it at the end of the year and go, okay, well, that's neat. It's the last time they see it. If you have yield data laying around that you're not using without a doubt, that can be very valuable, um, in your, your quest to create management zones, like I said earlier, yield data was what I found that most accurately captured the variation across your field from year to year. Additionally, with my research, I looked at grid sampling and I looked at what size grid, uh, provides you the most economic return. Cause as your grid size gets smaller, that means you have more samples to collect across that field, which you would assume you would more accurately capture the variation in that field, but that comes at the cost of having more samples and paying somebody the time to collect those samples. So I figured in, uh, paying somebody 25 an hour to collect their samples and$6 per sample. And we did this across 500 acres. Um, so at the end of the day, I calculated that the, the economically optimum grid sampling size, um, was around one acre. So at one acre your costs of paying somebody to sample become higher than the benefits of more accurately capturing the variability in that field.
Speaker 1:Well, that's very interesting data that that's the kind of information that producers are looking for and to utilize and understand,
Speaker 2:But the follow up on Alex's one acre grids that's, uh, absolutely what we found was the one acre grid that he mentioned was the economically optimum grid sampling size. Um, that though in context is representative of Southeastern coastal plain soils, right? Those were the soils in our area. We, we anticipate that that economically optimum grid size is gonna be different in different regions, according to how much variability is present in the field. So in areas where there's not a tremendous difference from one side of the field to the other, that optimum grid size would be much larger than that. Uh, the other thing that Alex found in, in his work was that going to larger grid size is in our area. Uh, it only cost an extra dollar, 30 an acre to do it. So in other words, if somebody's in a five acre grid, it's not substantially different from where they're at in a, in a one acre grid.
Speaker 1:One last question I have on this topic is when, when we look at this whole, you know, topic of variable rate and, and grid sampling and zone managements, and the processes that we go through in a year like this, where we are seeing extreme dry conditions and parts of north America and extreme wet conditions and other parts, um, the time of the year is kind of getting pushed around and seeding season might be brought ahead earlier while you're trying to hit sub soil moisture in a drought ear, or it might be pushed back. If you're trying to get rid of water, is, does this type of method allow us to be flexible in changing our data, to maybe be more conducive into dryer ears or wetter ears, or what years?
Speaker 2:That's a tough one.
Speaker 1:<laugh><laugh> I had to try and stump you guys once.
Speaker 2:So bottom line in a dry year or a wet year, your benefits, a variable rate application are still gonna be there, right? You're still gonna see, uh, we don't try to reduce inputs in variable rate application. That's not what it's about. And that's something that we have a hard time convincing growers. You're not gonna save on the amount of money you spend on fertilizer. And, and that's often the that's a misconception that we see. That's not the objective. The objective instead is to redistribute your fertilizer is to take it from the areas of the field where you would've otherwise over applied and drop it into the areas where you would've otherwise under applied. So essentially what you're looking at doing is maximizing the value of those fertilizer inputs, not reducing the fertilizer inputs in and of themselves. So again, wet year, year, you're still gonna get that benefit out
Speaker 3:Like that. That's one of I'd like to add in that that's one of the major benefits of creating a composite yield map from several years of data is that it factors in wet years and dry years and how that can affect your fields. Cause we've seen, uh, some fields where in a wet year, you have a part of the field that floods out and you lose yield there and in a dry year, um, that's your best yielding part of the field, cuz it retains more moisture. So that's one of the big benefits of creating a composite yield map. Is that in fact's in that yearly variation in the, in the weather?
Speaker 1:So in summary I guess, uh, you know, it's, it's been pretty well concluded that variable rates, uh, no matter the size of the farm, you know, the weather conditions that you live in and work in, uh, variable rates certainly has the ROI that especially in today's economy, as mentioned with input costs and, and everything that's going on in the world, uh, the ROI of, of variable rating is certainly growing. It's getting larger as we speak. Um, and now would probably be a great time to adopt it if it's not already adopted on the family farm. I think that brings us to the conclusion of today's talk on talks podcast. I'd like to thank Dr. Kendall, Kirk and Alex Cole from the Clemson university for their time today on this topic of variable rating.
Speaker 2:Thank you, Dave. We appreciate your time.
Speaker 3:Thank you guys
Speaker 1:For more podcasts. Please check us out at any place that you get your podcast from, including Spotify and apple. Thank you guys very much. Once again for joining us today.