Nitrogen Roots

Jackson: Welcome to the FarmBits podcast, a product of Nebraska Extension digital agriculture. I'm Jackson Stansell.
Samantha: And I'm Samantha Teten, and we come to you each week to discuss the trends the, realities, and the value of digital agriculture.
Jackson: Through interviews and panels with experts, producers and innovators from all sectors of digital technology, we hope that you step away from each episode with new practical knowledge of digital agriculture technology.
Samantha: Hello and welcome to the 32nd episode of the FarmBits podcast.
Jackson: This episode marks the beginning of our nitrogen management technology series in which we will focus on nitrogen management as a whole as well as the technologies that are being developed and iterated upon to improve the quality of nitrogen management.
Sam: To kick off this series, we welcome Dr. Richard Ferguson to the FarmBits podcast.
Jackson: Dr. Ferguson is currently the vice chancellor at the Rwanda Institute of Conservation Agriculture and is also a professor in the agronomy and horticulture department at the University of Nebraska-Lincoln.
Sam: Dr. Ferguson provides an overview of the history of nitrogen management research and offers background on the technologies that have been developed to further improve nitrogen management and what may impact the adoption of these technologies.
Jackson: We are very glad to welcome Dr. Ferguson onto the podcast and believe that you will get a lot out of his perspective.
Sam: So, we'll just start off by having you tell the listeners a little bit about yourself, your background and your current role.

Richard: Well, I spent the majority of my career at the University of Nebraska. I've been affiliated with UNL now for 36 years and that career has been a majority of it. I had a research and extension appointment and then I was hired with a focus on nitrogen management and water quality to help address issues, particularly in the Platte Valley but other parts of the state that have had challenges with groundwater, nitrate contamination and as it turned out that was kind of a lifetime career it's not been fixed yet, I think there's been much progress made on that issue but there's still concerns there and it's something that there's still work to be done.
I for about half of my career was based at the research center at the Clay Center and then in 2002, I moved to lincoln and took on soon thereafter took on also a teaching appointment. So, I began helping to teach along with a co-instructor from biological systems engineering a course on site-specific crop management and really enjoyed that. I taught that jointly for about a decade or so and then starting about 10 years ago, I started to be more involved become gradually more involved with administration and that led me eventually to focusing more on administration and served in that role at the University of Nebraska for a while and then two and a half years ago moved to Rwanda to help start a new institution in Rwanda. I'm focused on conservation agriculture, it seemed like an exciting opportunity to help start something new with something that I hopefully have some capacity to help contribute to both in my scientific discipline and to help administer, so that's what I've been doing for since the start of 2019.

Jack: So, you mentioned that you were initially brought on to work on soil fertility and water quality and nutrient management and so can you tell us a little bit more about your experience working out there in the Platte Valley and maybe down there at Clay Center with nitrogen management in particular.

Richard: At its core, it's really not changed much in 35 years, a lot of interest in getting the rate right and the timing right, some emphasis on source and certainly placement so those were ours that go into nutrient management. I would say that things gradually were refined, my focus was on irrigated systems and primarily corn in Nebraska so a fairly narrow focus if you think of all the questions that could be pursued but that's in the corn belt those are probably the central questions is how to manage nitrogen on corn in a way that's profitable and environmentally as safe as possible.
My work focused a lot also on the use of inhibitors and the evolution of inhibitors over time. I did a lot of work with industry as they came out with new formulations, new products before they came to market, most industry will partner with universities to test products that are coming to the market in two or three years just to get an idea of how these products perform in certain climates and soil environments. So, it did a lot of evaluation of inhibitors as well as timing and rate of nitrogen.

Samantha: Can you talk, you said that the nitrogen research maybe hasn't changed so much over the years but how has like farmers priorities or perspectives on nitrogen management changed throughout your career?

Richard: Really not too much. In terms of how they think, in terms of how they act it has changed a lot. When I started at the University of Nebraska, there were it was very common for fertilizer rates of objection fertilizer to be well over 200 pounds in action per year/ per acre, 300 pounds per acre was not uncommon and the yields were maybe half of what we might achieve today. A lot of that was related to the fact that it was a very inexpensive input the price of the fertilizer was very low compared to the value of the crop. It's also not changed a whole lot it has some fertilizer prices have certainly gone up but starting in the 60s which was before my time in the 70s as well. I started with University of Nebraska in 1985. So, in the 60s and 70s there were trends that were emerging of elevated nitrate levels and groundwater that were concerning, and so University of Nebraska faculty worked on addressing that, figuring out how to manage in a way that would lessen the impact of fertilizer use and so the efficiency with which farmers have used nitrogen fertilizer partly informed by research and extension but just market practices and improvement in cultivars and genetics all of that has driven the efficiency much higher than it would have been 30 or 40 years ago. So, farmers are doing a much better job now than they would have been 30 or 40 years ago, but still their focus I think is primarily on a mix of optimizing profit and optimizing yield. I can't argue with that, that's how it should be.

Jackson: So, what exactly is it that makes nitrogen management so challenging maybe particularly here in Nebraska but just in general in any sort of row crop production agriculture?

Richard: Well, in a sense it's a little less challenging than irrigated systems now, so that's an advantage that we have is that we can control water, right. More-so, if not totally a bit more-so. But, certainly water drives nitrogen so as water moves through soil it carries nitrogen with it and nitrogen is a very dynamic input or entity, and so it has many forms that it can take and it has many lost pathways in the soil both with water as well as to the atmosphere, and so it's sometimes attractive to farmers to hedge their bets or to guard against minimizing profit or minimizing yield by being sure that the rate of fertilizer is high enough that they can absorb some of those losses and still not reduce profit or yield. Sam: You touched on this a little bit earlier, but can you dive into a little bit some of those environmental impacts of nitrogen rates that are not well, they're sub-optimal of what they should be?

Richard: Well, in Nebraska the primary impact is groundwater quality and then the impact that has on drinking water. Most of Nebraska gets their water from groundwater and we're blessed to have a vast resource of groundwater under the Sandhills. There's a tremendous resource, but it's generally not used heavily for irrigation. I expect someday that will be a resource that will be a lot of interest in starting to tap more extensively, but that's particularly in areas where communities rely on fairly shallow groundwater that is more easily contaminated more. Earlier, let me put it that way just because groundwater is deeper doesn't mean it won't be eventually contaminated, but if it's groundwater is only 30 or 40 feet below the surface nitrate that's leaching can reach that much sooner than if it's 100 feet or deeper. So, that's the primary concern and there's the health risk because of consuming groundwater that's high in nitrate both to people and animals.

Jackson: Sure, so when we think about trying to improve nitrogen management and typical row crop production even before we start thinking about site-specific management or anything like that- what are some of the major immediate steps that producers have taken over the past you know 30 years that have resulted in the best optimization of their nitrogen management maybe thinking about you know just techniques in general that they've started to use?

Richard: Well, going back to the four Rs of nutrient management so placement and timing rate and source, all of those I think farmers have a fairly decent handle on. It's been interesting to see the evolution in practices over the time that I've been in Nebraska. When I started Nebraska about 75% of the nitrogen that was used in the state was from anhydrous ammonia and ammonia has certainly a number of advantages in terms of generally it's the lowest price per pounded in it does have a higher cost of application but it's also initially the least likely to be lost certainly through groundwater or to groundwater but there's been a gradual trend, I unfortunately have not tracked this for the last eight or ten years. So, I don't know where it stands now. The last I knew about 65 percent of the end sold in the state was as solution, nitrogen solution and that's a very versatile source of N, can be used through an irrigation system that can be sprayed it can be injected. It contains urea, ammonium and nitrate so it has three forms of enzyme that are directly plant available, some that will be as as the fertilizer converts, but it also has more risk of leaching or volatile loss. So, fertilizer unless if it's not handled or handled in terms of application method or placement or timing it is higher has a higher risk of loss than anhydrous ammonium.

Sam: And you mentioned how the irrigation provides some advantages for sure when it comes to nitrogen management maybe specifically like fertigation, can you talk about how that timing and splitting of that application is so important for effectiveness or maybe how in other parts of the state where rainfall is limiting how some of that timing is really important to think about?

Richard: Again, if I go back 30 or 40 years, fall application was kind of the norm so soon after harvest- anhydrous ammonia would be applied and initially that's okay because it's in a form that won't leach, but if soils are warm enough it will convert to nitrate and then become leachable. So, what we tend to see is that the highest rainfall amounts in Nebraska are May and June and so most commonly much of the ammonia applied in November would have converted to nitrate by that time and be leachable with rainfall, so as far as timing goes there's been a lot of improvement in moving away from fall application. Fall application is not necessarily always bad, I'd say most often it's riskier than we would like because it can convert to nitrate but they're in some soils especially if one thinks about using inhibitors there is the potential that it can be a reasonably safe approach, but also if you go back 35 or 40 years majority of irrigation in Nebraska was furrow instead of sprinkler irrigation, and it was much harder to control the rate of irrigation water especially at the first irrigation because after cultivation and ridging and developing the furrows soils would be very loose and when you try and run water down that furrow it tends to be very absorptive, so water infiltrates at a high rate so if you put that high infiltration rate of irrigation water which would probably occur in late June early July, maybe with a high rate of fertilizer that's been applied in the fall that's present in the nitrate form irrigation was a big driver of leaching 30 years ago, I would say it's not today with sprinkler irrigation and which allows us to optimize the timing and also allows us to optimize the rate of application of irrigation water. Generally, I don't think there's significant risk of a lot of nitrate leaching during the growing season once one starts to irrigate ,so the movement in practice certainly has helped us from that high risk of nitrate leaching with fall application and fertilization that's been a tremendous improvement to move to sprinkler irrigation.

Jackson: Sure, so how exactly so you know we've talked about kind of timing and you know trying to get those 4rs you know kind of improved across nitrogen management, when you think about spatial variability and specifically thinking about nitrogen rates how exactly do some of these really variable fields that we have in Nebraska and that you also see in other parts of the United States impact what that right rate is at a given point in the field and how are we trying to respond to that?

Richard: I and a couple of other UNL scientists started variable rate nitrogen research in the early 90s our first study was in 1992 in Adams county, and it was we did that because we felt like was intuitive you can see variation in crop response, drop color across fields and we know that a lot of that is related to nitrogen. Some may be other nutrient stresses or other pests but much of that is related to soil and supply and we just felt like it was intuitive that a significant improvement and then use efficiency could occur if we could match the rate of fertilizer that we apply to the need that's present in the field. I still think it's pretty intuitive but it's turned out to be a lot more complicated than we thought 30 years ago that our first research was our approach was to use the university algorithm an earlier form of the algorithm that exists now but still we're trying to predict what the economic optimum rate of fertilizer would be based on soil tests, primarily and historic yield. And the first I would say five to eight years of research just were not very productive because we found that to not really be a good approach to try and predict the optimum rate of fertilizer based on soil tests and historic yields part of that was because we didn't have historic spatial yield yet all we had was average yields, yield monitors didn't exist. I think we used an experimental yield monitor first in 1993 or 94 and they started to become available for farmers then in the mid to late 90s that certainly helped to know what the yield trends would be on average across the field, but trying to predict what the optimum rate was we felt like it wasn't as productive as some other directions that have been taken since.

Sam: Sure, so yeah can you talk about some of those newer technologies like you said where we've gone since to manage for some of that spatial variability?

Richard: At the time that we were using a soil test based approach like probably in the late 90s I'd have to go back and look at the exact year but the USDA ARS unit in Nebraska particularly led by Jim Shepherds started to do some fairly basic work on use of sensors to look at the crop and as time went by that direction seemed to be very fruitful. We've been using chlorophyll meters, handheld chlorophyll meters from the mid 90s maybe somewhere along in there that obviously is not an approach that a farmer would use but it's very useful for for research and that kind of complimented- we had a project that started the year after I joined the University at Nebraska and basically Clay Center, we did a lot of leaf tissue testing for chlorophyll. We would take punches out of leaves instead of the whole leaf we had a device that would take a leaf punch and we could quickly analyze that in the lab for chlorophyll content and we soon found that there was good correlation between those measurements and what a chlorophyll meter optically would let us assess. So, gradually as time went by the use of optical sensors to assess nitrogen status seemed to be a very promising direction to take and so for probably last 20 years that's been kind of the focus of the research in Nebraska has been on use of crop canopy sensors.

Jackson: And there have been some other research there I guess there's been other research out there at other universities like Iowa State for example, looking at models as well for for spatially variable nitrogen management is that right?

Richard: Certainly, I would say that there there's has developed a strong modeling effort at Nebraska as well but probably some other states other research institutions had a higher degree of modeling focus than what we did in Nebraska. For a while, not that you have to rely on a model or a tool that's developed at your university yes your state but for a combination of reasons we weren't using models much in Nebraska probably until the last six- eight years something like that as a tool. I would say that they're getting much better, they have a lot of potential on a field average basis there's still well the last I knew since I've been out of the science now for a few years, I'm sure things have evolved that I'm not up on, but incorporating spatial variation within a field has been up to a few years ago at least a weak point in models they just didn't have interface with the soil properties or spatial properties of soils and fields that was needed.

Sam: Can you elaborate on maybe some of the advantages or challenges of some of the other tools as well, so you know what are some of those challenges with sensors or the optical sensors?

Richard: Well, certainly other sources of stress will influence sensors. We have options today of both passive and active sensor capacity that rely on the sun and actively have their own light source, so obviously you can't use a passage sensor at night. The advantage to an active sensor is it's more or less not influenced by the sun. There are factors that influence the canopy, how light is reflected or absorbed in the crop canopy that can influence sensors. The presence of dew, significant amount of water on the crop canopy can have some influence on sensor use if you're talking about proximal sensors the atmosphere has little influence if you're just a few meters or less away from the crop canopy, but once you start to have an aircraft or a satellite-based sensor then the atmosphere certainly has an influence especially if it's cloudy why a satellite's not going to be very useful right. Temporal density has been an issue, I think nitrogen as we talked about is very dynamic, so in a matter of a few days a plant's nitrogen status can change and so you'd like capacity to be able to assess a crop with some high degree of temporal density fairly often every few days especially during the crops critical growth stage where it's really important to be on top of limiting stress and it's not very feasible probably to go out with a drone every other day, expect a satellite to go over every day but that's starting to change. Not that you'll fly a drone every day but satellite can occasionally be achieved with a daily frequency or often enough that you can get data frequently enough that you don't have as much concern about the temporal density.

Jackson: Absolutely, so how some of these sensor based tools in particular been developed how have they been studied and researched you know kind of since they were first conceived here in Nebraska or you know with Jim Scheper's group in the mid 90s and maybe through like the the 2000s.

Richard: Yeah, well I would go back and say there's a lot of research elsewhere particularly at Oklahoma State University and some other land-grant universities that had very excellent research on sensors and a lot of synergism. You're both aware that there's been probably 15 years ago now, there's a research group that meets every summer, focused on sensory action management that's evolved kind of almost a national meeting now. I would go back and say that a lot of that started with very foundational basic work, so just an understanding of how crop chemically reflectance is influenced across different wavelengths. Antoly Edelson was a researcher at the University of Nebraska that did some very excellent foundational work on developing vegetation indices related to reflectance of different wavelengths that informed about sources of stress that evolved into lab research and then small plot research and then field scale research. All of those go together I think in developing a system that's useful today by growers and systems that have been commercialized.

Sam: So, earlier you talked about the history and how producers have adopted some practices specifically the timing in the source how have they been about adopting some of these technologies and why is potentially slowing their adoption of the technology?

Richard: Well, we've wrestled with that for many years not just with sensor technology, with other technologies and hip inhibitors are an example of that we have good research that shows many inhibitors are effective in doing what they're supposed to do and yet when it comes to wide scale adoption of them why it's not there, I think farmers tend to adopt practices that they can show work for them especially if they're easily adopted and the economic benefit is obvious there are other precision practices that have been fairly widely adopted by growers now at a higher rate that came along later than variable rate action use, auto steer for example is the standard now, tractors largely have auto-steer on them, and the benefits to them are obvious. I have to surmise that it's sometimes the case that the benefits are not as obvious or as significant farmers to adapting some of these practices. Some of these unfortunately take time or a fairly high level of management and farmers only have so much time and they only have so much time to go to management. So, if the benefit to them doesn't outweigh the complexity or time that it takes why it's probably not worth adopting, so I'd say there's it's a complex issue- I can't say that there's any single reason why sensor technology is not more widely adopted. I would say that in some cases, I'm guessing it may take some regulatory approaches where water quality is really being impacted and to go to the next level of efficiency that's really needed to continue to grow corn in those areas, we may have to have some regulation on what practices can be used what timing of fertilizer is allowed things like that and some of that has occurred in Nebraska already with groundwater management districts that are in place and those have certainly been beneficial, and I don't think have had a negative impact at all on farmers productivity or profitability.

Jackson: I think we'd like to dive back into that a little bit more here in a few questions, but one thing that you said there is that farmers you know tend to adopt things that they can easily demonstrate is helping them with profitability and even sustainability probably now as farmers are starting to care about that aspect a little bit more and when we think about profitability and sustainability metrics like nitrogen use efficiency, I typically think of how challenging these metrics really are to quantify and on-farm research trials given some of the constraints can you talk about some of those challenges that you face in terms of getting good metrics to present to a farmer regarding these technologies?

Richard: Yeah, to directly measure nitrate loss to groundwater from a field or a practice or a plot is very challenging. We've done that to some degree and some research projects I've been involved in but because the act of measurement influences the system, there's always some uncertainty about how accurate the data is. So, a lot of it has to be inferred indirectly, which I think is a that's defensible if you apply so much in to a field and you get so much out in the crop you can infer that the rest of the N has gone somewhere right. They didn't stay in the soil or been lost or to the groundwater, lost to the atmosphere. But, a lot of regulatory agencies, a lot of farmers like hard numbers, exactly what does this practice do in terms of reducing environmental impact and improving profit over time. I think an approach that we've used that we started using in project sense, which both of you have been involved in was to infer efficiency through partial factor productivity, so it's indirectly measuring the amount of yield produced per pound of fertilizer applied and then partial profit what is the difference in gain and profitability or not by the use of this practice compared to some other benchmark that we would use and then combining those two. So, a practice that's going to maximize efficiency is not ever going to be the most profitable and the inverse if you're maximizing yield, you're not going to be the most profitable and you're certainly not going to be the most efficient, so what a farmer I think understands and would like to do, and I think regulatory agencies as well is having a good compromise between optimizing profit and reducing loss or to the groundwater or atmosphere and in project sense we've been able to show that the use of sensor based technology can optimize both of those metrics. It's not going to maximize yield, usually if you're maximizing efficiency you'll be somewhat below maximized yield and that may be slightly below what farmer is used to yielding, but if you can show him that you're going to earn more money by giving up that last five bushels per acre it seems many farmers are willing to accept that and adopt those kinds of practices.

Jackson: Sure, one additional question I guess that brings up is kind of this concept. We've had a few growers that we worked with in project sense who brought up the idea that the reason why they push for yield is kind of a risk management strategy in a lot of ways and so what is kind of the complexity there of the risk management side, making sure that you have enough grain in the bins to cover you in a bad year or even getting the insurance you know yield numbers high enough to where you're going to make sure that you're covered in case of an environmental disaster versus what that year-to-year profitability actually looks like?

Richard: Yeah, I probably have to plead a bit of ignorance
because I certainly know the farmers have other metrics and other factors that go into the equation of how they make the decisions, and I don't pretend to understand them all and they they will vary with the farm program, or their landlord, with their bank. Many factors influence those decisions besides just what the economic optimum rate should be. I guess I would just come back and say, long term I think it's going to be in farmers best interest to try and do everything they can to optimize profit right on a given field or given acre.

Sam: Yeah, do you think that nitrogen management will become even more of a priority in the future, so thinking along the lines of like I said farmers have a lot of challenges, there's lots of things that they worry about and nitrogen is relatively cheap on you know all the crop inputs. At what point will nitrogen become you know just a huge priority that we're going to have to really take care of?

Richard: Yes, I expect that I think it has moved that way over the last 20 years, I think the natural resource district approach that has been taken in Nebraska has been an excellent approach, it's something that's localized both in terms of how the regulation if that's part of it is applied so the regulations are appropriate to the soils and the climate and the groundwater situation, but it's also managed by a local group of elected officials that the board members of the natural resource district they live there many of them drink the water that's coming right out of the district. So, people locally understand the issues and are looking for the best solutions for that, but it has been a regulatory approach. The first regulation went into place in Nebraska in 1987. That has been a change from what farmers have been used to doing in the past. I think over time the majority of the population in the U.S. or Nebraska is not from the farm, they live in cities and they're going to expect that their resources particularly water supplies are sustainable and with high quality, and I think it's mostly inevitable that there's potential for more regulation sure and in some ways what we'd like to avoid is regulation that's arbitrary and broad brush and applies everywhere in the same way. So, I think there's some advantage to adapting more localized regulation earlier that we consider to be more appropriate.

Jackson: Yeah absolutely, so what do you think in terms of our nitrogen use efficiency what do you think is actually a practically achievable goal, and I know that may vary you know from location to location as we were just talking about but you know it may be in an optimal location versus maybe a sub-optimal location thinking you know the eastern part of Nebraska where we have a lot of heavier soil textures versus more of our Platte Valley where a lot thing a lot of soil textures are more sandy what do you think is really achievable as far as nitrogen use efficiency goes on the farm?

Richard: I think that's the wrong question, Jackson. In a sense, it's certainly one that we need to think about right but when I left Nebraska, came to this position- one of the things that I struggled with that I had a lot of interest in continuing the research that we were doing and particularly moving towards where we're managing stress, minimizing stress of the crop just like we do with water. We don't apply all of the season's worth of water to the field all at one time right it leaches out soil can't hold it so we we irrigate when the there's a lot of information that we have now that's saying we're starting to run out of water in the soil and with sensors and other approaches for modeling that we say now it's time to water without that one can just observe and see that the crop is starting to curl during the part of the day and so that's an indication that maybe it's starting to be short on water available from the soil. So, I think the ultimate goal is to minimize nitrogen stress in plants and to be able to detect the onset or anticipate the onset of stress in such a way that you apply or the plant has available to it the amount of nitrogen that it needs for the next whatever period of time. It's manageable whether that's a week or a month or instead of saying well so what that turns out to be then the the rate of end that you apply per bushel, really starts to be a bit meaningless by just applying the amount of event needed to minimize stress and yeah for some parts of the field that might be two pounds of N and some parts of the field you may apply no fertilizer if you have certain soils in certain situations. I think that's what our goal should be right now it's not feasible for farmers to apply fertilizer every other day or revery week, but I think technology is evolving to where that can become feasible someday, particularly in irrigated systems.

Jackson: Yeah, I couldn't agree more I think it's a great way to to frame that is that you know the NUE that you're going to achieve in a given year is going to change you know basically every year. You're never never going to have the exact same that optimizes for that particular crop and then it also changes as you said by by location. So, I think thinking about minimizing stress is a really good way to frame what we're trying to do with nitrogen management.

Richard: There was, I believe it was 2012 in Nebraska across the corn belt was a record drought and in states like Indiana, Illinois, Iowa was devastating we saw some of the highest yields and the highest end use efficiency ever in some of my research studies in Nebraska just because we didn't have rain but we had irrigation right, so we didn't have rainfall that complicated the nitrogen and irrigation management. We could irrigate as needed it was certainly a very costly year, so it was very expensive to try that much water but we didn't have the uncertainties and variation in an end supply that resulted from variations in rain and then the constant wetting of the soil and maintaining an optimal environment for mineralization, generated huge amounts of mineralized nitrate from soil so very high in these efficiencies from fertilizer in that year.

Sam: And thinking about how we are going to potentially one day achieve some of these things that we talked about, what kind of technologies are you excited about or want to explore more or really think that things are going?

Richard: It's interesting to think about these technologies particularly as it relates to what I'm doing now and how that compares to Nebraska, thinking about a small older farmer in Rwanda that their entire farm is an acre an acre and a half and they their technology as a whole and yet there's there's very inexpensive tools that allow us to understand properties in fields at small scale. So, one of the things that we're going to be doing at my institute is thinking how these sensors and precision technologies relate to a smaller farmer in east Africa. And some of those questions I think are not different whether you're an irrigated corn producer in Nebraska or a smaller farmer in Rwanda, obviously we're not using yield mapping combines on crops here, but I'm very excited about the evolution and sensor technology that I'm seeing. There is a lot of enthusiasm here about drones, and we'll start teaching the use of drones and sensors in a class here this fall, Rwanda's was and I think still is one of the leading countries and using drones to deliver medical supplies. So, the company Zipline their first operations to deliver blood supplies was based in Rwanda. So, there's the use of drones across the country to deliver medical supplies in Rwanda. When I started, I actually started using drones and research in Nebraska 22-23 years ago something like that and it's been exciting to see the evolution and drones as a platform for using sensors. I think I'm not certain that that's where it will end, I think drones will have a lot of flexibility and use for a lot of management and crop production but if you're trying to cover a large area with a high degree of temporal density, I'm not sure whether drones are the best platform probably, someday satellites may be more likely to be a better platform, if they can see through clouds. So, I'll be excited to see where sensor technologies go on satellites particularly over the next few years.

Jackson: I do want to ask, you know we've been talking about nitrogen management from kind of the U.S. or Nebraska's perspective for the entire interview, but how does nitrogen management rank in terms of the challenges that small shareholder farmers there in Rwanda are facing or is it even is that even something that is toward the top of their priority list to solve.

Richard: It's not at the top, it's certainly an issue that things are different in so many ways here. A real challenge is that fertilizer is much more expensive it's probably two or three times the price per pound of nutrient here as it would be in the U.S. or Europe a lot of that's related to the lack of supply and farmer average per capita income is I think seven or eight hundred dollars a year. So, the ability of the farmer to buy fertilizer is not very high, so if they are buying inputs they have to figure out what is the input that's going to make them the most money. Of course, and there are tools that are available to help optimize selection and rate the fertilizer, so if a farmer only has thirty dollars to use on their farm for inputs how do they divide that up between nitrogen and phosphorus and lime and pesticides. So, the challenges are are high if you're a small older farmer, there are more enterprise scale and production systems here not large many thousands of acre farms in Rwanda, but there are larger operations that are more mechanized and they do rely more on inputs of fertilizer and hybrid seed and things like that. I would say nitrogen management in terms of what we think of in the U.S., for ours probably are not too relevant it's just can I get fertilizer or not and can I afford fertilizer or not?

Jackson: Well , going you know i guess to kind of wrap up our interview we always ask what advice somebody has for anybody that you know is kind of thinking about this particular topic we're on, and so from your experience what advice do you have for either researchers and or farmers/producers out there regarding nitrogen management, what questions to pursue or maybe how to improve that on their farm?
Richard: I guess I would not worry about not having a career I think even at your age if you're asking a question you think well this might this might be figured out in the next within my career what do I do if it's all fixed, and I don't think that's likely to happen. I could have asked that question when I started 35 years ago and it's not something that's solved overnight or over a decade or over a career even. It is a very much an interdisciplinary question, so seeking out interactions of disciplines and expertise you most of you have obviously engagement with engineering and agronomic faculty and there are faculty and and some of the more basic sciences like in the school of natural resources and sensor technology and modeling. I do think that modeling has a lot of potential to help improve how we do things and as models get more sensitive and fine-tuned, I think they'll be very beneficial. I don't know, I think persistence and just continuing to ask questions that are informed by growers it's important a lot of the great research ideas that I was involved in came from growers and problems that they have, and I was trying to help them out. The advantage of a research extension employment is you get try and figure some things out and then you can take it back to folks and say does this help, and they'll come back and say well that helps a little bit let's work on it this way and so it's an iterative approach that I think is really a valuable approach. I would also indicate that I think potential is going to grow that it will need to be researchable and probably extension will be conducted jointly with industry has a lot of capacity to put resources into specific questions that we can benefit from in academia and vice versa, and so I had some excellent engagements in collaboration with industry and I think that probably just going to grow.

Jackson: Thank you very much to Dr. Richard Ferguson for taking the time to join us on this episode of the FarmBits podcast. I really enjoyed getting to hear some of his perspectives, again it's been a while since we had a chance to catch up with him last. I think my favorite part of the interview was actually when he kind of flipped one of the questions that I asked about you know how what really is our achievable nitrogen use efficiency and really he said it's the wrong question to be asking it's how can we minimize stress on the plant and really optimize for maintaining nitrogen sufficiency throughout the growing season because if you do that then you're really going to achieve something with nitrogen management that's beneficial to both the grower and to the environment, which is really what we're looking for.
Sam: Yeah, that was really interesting, I also loved his discussion on the history of nitrogen management specifically in Nebraska so we've come so far from gravity irrigation which can be really detrimental to nitrogen leaching and then now we're using fertigation with center pipettes and how far we've come in Nebraska when it comes to nitrogen management so for sure.
Jackson: With that thank you so much for joining us and we hope you will join us again next week as we interview another University of Nebraska faculty member Dr. Laila Puntel as we discuss nitrogen models and some of the research going on Nebraska regarding those. With that thank you so much for joining us and we hope you will join us again next week as we interview another University of Nebraska faculty member Dr. Laila Puntel as we discuss nitrogen models and some of the research going on Nebraska regarding those.