Are Bio-fertilizers the Next Frontier in Soil Fertility and Fertilizer Technology?

research tractor in the fieldThat is yet to be determined of course, but we do know that the biological and bio-fertilizers market is estimated to grow from a current market worth of $6.7 billion to $12.9 billion by the year 2022. What’s this mean if I am a farmer? A rapidly growing biological market aimed at the agricultural sector means farmers need to become educated about what biologicals and bio-fertilizers may and may not be able to offer them. Over the last 4 months or so I have been browsing the scientific literature educating myself about what we do and do not know about these bio-fertilizers. I have learned that due to advancements in genome sequencing it is now much easier, faster and cheaper to identify and isolate specific bacterial and fungal strains that do in-fact provide services that can improve plant growth and yield.

Some of the agronomically important services bio-fertilizers may be able to provide include: atmospheric nitrogen fixation for cereal crops (corn, wheat, etc..), bacteria that are able to convert non-plant available forms of soil nutrients into plant available forms (phosphorus and potassium solubilizing bacteria), bacteria that can compete with plant pathogenic fungi and other harmful bacteria, and specific strains of bacteria have been shown to produce plant growth regulators (Indole acetic acid and gibberellic acids) that can stimulate root growth and development. See the bulleted list below for more specific details about what bio-fertilizers have been shown to be able to achieve is science-based studies.

Bio-Fertilizers 2018 Field Testing

Tractor in Field for Bio Fertilizer

The unfortunate part is that many of these known benefits of bio-fertilizers have been tested more often under greenhouse vs. actual field conditions. That said, there is an increasing amount of evidence that these bio-fertilizers may, in fact, be able to increase corn and soybean yields in actual field environments, but our knowledge in actual field conditions is clearly more limited than what has been shown in greenhouse studies. On this note, Liqui-Grow has partnered with several biological companies that are leaders in the bio-fertilizer market. We will be testing their most promising bio-fertilizer products at several locations throughout eastern, IA and northwest, IL in the 2018 growing season. My main objective at Liqui-Grow is to identify and investigate (in-formal field research trials) new and innovative products and crop management practices that can make our customers and our company more profitable – partner with us to find out what we learn.

Known Agronomically Important Services Bio-fertilizers Can ProvideBacteria

  • Nitrogen-fixing bacteria can add 25-45 lbs N/ac/yr (Azospirillum, Azotobacter) under optimum soil conditions and thereby can increase crop yields 15-25%.
  • Application of bio-fertilizers results in increased mineral and water uptake, root development, and vegetative growth.
  • Some bio-fertilizers (eg, Rhizobium BGA, Azotobacter sp) stimulate the production of growth promoting substance like vitamin-B complex, Indole acetic acid (IAA) and Gibberellic acids.
  • Phosphate mobilizing or phosphorus solubilizing bio-fertilizers/microorganisms (bacteria, fungi, mycorrhiza etc.) converts insoluble soil phosphate into soluble forms by secreting several organic acids and under optimum conditions, they can solubilize/mobilize about 30-55 lbs P2O5/ac due to which crop yield may increase by 10-20%.
  • Bio-fertilizers act as antagonists/competitors and suppress the incidence of soil-borne plant pathogens and thus, help in the bio-control of diseases.
  • Nitrogen-fixing, phosphate mobilizing and cellulolytic microorganisms in bio-fertilizer enhance the availability of plant nutrients in the soil and thus, sustain agricultural production and farming system.
  • Bio-fertilizers are a cheap, pollution free and renewable energy sources.
  • Bio-fertilizers improve physical properties of soil, soil tilth and soil health in general.
  • Blue-green algae like Nostoc, Anabaena, and Scytonema are often employed in the reclamation of alkaline soils.
  • Bio-inoculants containing cellulolytic and ligninolytic microorganisms enhance the degradation/decomposition of organic matter in the soil, as well as enhance the rate of crop residue decomposition.
  • Azotobacter inoculants when applied to many non-leguminous crop plants, promote seed germination and initial vigor of plants by producing growth promoting substances.

Bio-Fertilizer Services Reference: Agriinfo

Bio-Fertilizers Field Testing

Comparing High Ortho and Conventional Polyphosphate Starter Fertilizers

2017 New Research

High Ortho and Conventional Polyphosphate Starter Fertilizers
Planting starter fertilizer trials near Traer, IA in the growing season of 2016.

Article Summary

  • Orthophosphates are 100% plant available, but a high percentage of polyphosphates in starter fertilizers convert to ortho-phosphate within just two days after application.
  • This quick conversion from poly to orthophosphate suggests expensive “high” ortho starter fertilizers are not likely to result in increased corn yields compared to conventional polyphosphate starters.
  • On-farm field studies conducted near Traer, IA in the 2016 and 2017 growing season found no statistical difference (Pr > 0.05) in corn yield between conventional and high orthophosphate starters in either year.
  • High ortho starters cost more per/ac than conventional polyphosphate starters but do not increase corn grain yields.

Polyphosphates Rapidly Convert to Plant available Orthophosphates

How the Field Trial Was Conducted

Given polyphosphates are not immediately plant available and orthophosphates are immediately plant available, this gives the promoters of “high” orthophosphate starters ample opportunity to muddy the waters. Nevertheless, the facts are, polyphosphates are rather rapidly hydrolyzed (converted to) into orthophosphates once applied to soils, and this hydrolysis process generally takes just 48 hours or so to complete.

In September of 2015, we posted a blog discussing some of the more technical reasons why the ratio of ortho to polyphosphates in starter fertilizers should have no impact on corn yields. For those that are interested in the more technical details, we encourage you to follow this link to the September 2015 blog post.

While we was relatively certain that the ratio of ortho to polyphosphates in liquid starters should have no effect on corn yields, we decided to “test” this idea with on-farm field trials located near Traer, IA in the 2016 and 2017 growing seasons.

How the Field Trial Was Conducted

In these field trials, we used two starters applied in-furrow at 6 gal/ac. Each starter had an NPK nutrient analysis of 6-24-6. The only difference between these two starters was the ratio of ortho to polyphosphates. One of these starters contained 80% orthophosphate and the other contained just 50% orthophosphate. With the remainder of the phosphorus source in each of these two starters being polyphosphate. Each plot was planted with a 24-row planter (Picture 1) and was nearly 2400 ft long. In both the 2016 and 2017 growing seasons the experimental design used was a randomized complete block with 4 or 5 replications.

on farm study near traer iowa 2016
on farm study near traer iowa 2017

Field Trial Results

Averaged over the side-by-side replications there was less than 1 bu/ac difference in corn grain yield between the high ortho and low ortho polyphosphate starters in both the 2016 and 2017 growing seasons. In addition to finding no differences in grain yield between these two starters, the high ortho starters generally cost about $1 more per/gal (so the $6/ac difference in price at a 6 gal/ac rate) than the low ortho starters. So the more expensive high ortho starter clearly did not “pay” its way in our multi-year field trials.

More Trials Planned for 2018

While our findings agree with other research-comparing ortho and polyphosphate starter fertilizers (Frazen and Gerwing. 1997), we want to be absolutely certain that our fertilizer offerings are the most economically viable products on the market. Therefore, we have decided to run this same field trial at one location in northern, IL in 2018, and at one location in central, IA in 2018. Stay tuned for those research results next fall.

Standing in front tractor on Traer, Iowa Farm | Liqui-grow

Want to learn more?

References
Franzen D. and J. Gerwing. 2007. Effectiveness of using low rates of plant nutrients. North Central regional research publication No. 341. http://www.extension.umn.edu/agriculture/nutrient-management/fertilizer-management/docs/Feb-97-1.pdf (accessed 8 of Sept 2015).

Fall or Spring Nitrogen Fertilizer Sources – Which is More Profitable?

Nitrogen fertilizer is one the most costly crop inputs following seed, and is also quite important for insuring top corn yields. In addition, nitrogen that doesn’t get taken up by a growing corn crop can cause environmental concerns. For these reasons, growers should be concerned with managing this valuable resource carefully. In this educational video Liqui-Grow's agronomy research lead will discuss evidence based research comparing fall vs spring nitrogen sources effects on corn yields and farmer profitability.

Watch on our YouTube Channel

Video Summary

  • Following the 4R’s of nutrient stewardship (the right placement, timing, source and rate) will often lead farmers toward greater crop yields and higher nutrient use efficiency.
  • Applying nitrogen fertilizer for corn production in the spring vs the fall is a great example of the “right” time.
  • Science based studies conducted by the University of Illinois, Minnesota State University and by Iowa State University shows on average a 7.9% yield increase for spring vs fall nitrogen applications
  • Economically these studies clearly show that spring applied nitrogen is the most economical decision for Midwestern corn farmers. In some cases, growers might be able to increase their per acre profit by $43/ac by switching from fall to spring nitrogen sources.

Download the Excel file and use as a tool to plug in your own numbersFall vs Spring Nitrogen Economics

The Nitrogen Grand Challenge

Environmental Stewardship and Liqui-Grow

Environmental Stewardship is essential to what we do at Liqui-Grow. We are extremely committed to helping farmers gain more crop yield per dollar spent on fertilizer while also protecting the environment. Since this is a mission at Liqui-Grow, we’ve decided to take part in the Nitrogen Grand Challenge.

What is the Nitrogen Grand Challenge?

The Nitrogen Grand Challenge, hosted by Tulane University in New Orleans, Louisiana, invites competitors that will provide new and innovative ideas to farmers on managing nitrogen fertilizer for maximum profits and environmental sustainability. The competitors are graded by a formula that incorporates production cost, crop yield, and nitrogen use efficiency; which are all key components of a cost-effective, sustainable nitrogen management program.

There are 3 Phases:

  1. Contestants submit their ideas.
  2. Five best ideas get battle-tested. The five best solutions will go into the ground to see if their idea works on a farm in Northeast Louisiana. They will each get a plot of land to test their specific technology during an entire growing season.
  3. Knockdown drag out fight between two finalists. Judges will determine the winner from the top two contestants.

What is the problem?

“Throughout the world, increasingly fragile coastal and inland lake ecosystems face a common and persistent threat; “dead zones” caused by hypoxia continue to challenge the integrity and productivity of environments that are home to a diverse biota and highly valued natural resources. Dead zones result from excess nutrients flowing from rivers to near-shore areas. Though hypoxia is often thought of as a challenge particular to the northern Gulf of Mexico, dead zones are a problem of global proportions.”

“Hypoxia occurs when the oxygen required to support life becomes depleted, which can result in severe impairment of near-shore fisheries. Consequently, dead zones can also destabilize the businesses, families, and communities that are sustained by fisheries. Further, nutrient enrichment can jeopardize the future of estuaries and coastal wetlands that depend on freshwater and sediment delivery for stability and persistence. In short, clean water is critical to the ecological, cultural and economic well-being of Louisiana, the nation, and the world.”

For more information on the problem, you can visit: http://www2.tulane.edu/tulaneprize/waterprize/the-problem.cfm

Liqui-Grow’s Contributions to the Grand Challenge

Liqui-Grow feels strongly about their customers’ return on fertilizer investment. A high return on every dollar spent on fertilizer often goes hand-in-hand with high nutrient use efficiency and Environmental Stewardship.

As part of our commitment, Liqui-Grow has enlisted their Agronomy Research Lead, Jake Vossenkemper, to participate in the Nitrogen Grand Challenge. Jake is participating on team CropSmith. They have used their innovative ideas on how to manage nitrogen more efficiently to beat hundreds of other teams. They are now competing in the second round of the Nitrogen Grand Challenge against 4 other teams. The winning team will receive a grand prize of one million dollars, but more importantly, they may lead to groundbreaking concepts of nitrogen management that will lead to greater farmer profitability and environmental sustainability.

 

Fertilizer Placement to Improve Crop Nutrient Acquisition and Yield

Summary

  • Fertilizer placement in soil improves plant nutrient-acquisition.
  • Many fertilizer placement techniques have been developed.
  • Fertilizer placement leads to higher yield than broadcast.
  • Fertilizer placement leads to higher plant nutrient-content than broadcast.
  • NH4+ + P or Urea + P placed at 10–20 cm soil depth shows best plant growth effects.

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New Research Comparing Ortho/Poly-Phosphate Ratios for In-Furrow Seed Safe Starter Fertilizers

Article Summary

  • Ortho-phosphates are 100% plant available, but a high percentage of poly-phosphates in starter fertilizers convert to ortho-phosphate within just two days of application.
  • This quick conversion from poly- to ortho-phosphate suggests expensive “high” ortho starter fertilizers are not likely to result in increased corn yields compared to seed-safe fluid starters containing a higher percentage of poly-phosphate.
  • A field study conducted near Traer, IA in the 2016 growing season found less than 1 bu/ac yield difference between a 50/50 ortho:poly starter and high ortho-phosphate starter.
  • High ortho starters cost more per acer than 50/50 ortho:poly starters, but do not increase corn grain yields.

Poly-phosphates Rapidly Convert to Plant available Ortho-Phosphates

Given poly-phosphates are not immediately plant available and ortho-phosphates are immediately plant available, this gives the promoters of “high” ortho-phosphate starters ample opportunity to muddy the waters. Nevertheless, the facts are that poly-phosphates are rather rapidly hydrolyzed (converted to) into ortho-phosphates once applied to soils, and this hydrolysis process generally takes just 48 hours or so to complete.

In Sept. of 2015, I posted a blog discussing some of the more technical reasons why the ratio of ortho- to poly-phosphates in starter fertilizers should have no impact on corn yields. For those that are interested in those more technical details, I encourage you to follow this link to the Sept. 2015 blog post: https://www.liqui-grow.com/farm-journal/.

While I was relatively certain that the ratio of ortho- to poly-phosphates in liquid starters should have no effect on corn yields, I decide to “test” this idea with a field trial in the 2016 growing season conducted near Traer, IA.

How the Field Trial Was Conducted

In this field trial, we used two starter products applied in-furrow at 6 gal/ac. Each starter had an NPK nutrient analysis of 6-24-6. The only difference between these two starters was the ratio of ortho- to poly-phosphate. One of these starters contained 80% ortho-phosphate and the other contained just 50% ortho-phosphate with the remainder of the phosphorous source in each of these two starters being poly-phosphate. Each plot was planted with a 24-row planter (Picture 1) and plot lengths were nearly 2400 ft. long. In total, there were 5 side-by-side comparisons of the two starter fertilizers that contained different ratios of ortho- to poly-phosphates.

Field Trial Results

In general, there were no large differences in yield between the two starters in any of the 5 side-by-side comparisons, except for comparison number 5 (Figure 1). In comparison number 5, the 50% ortho/50% poly-phosphate starter actually yielded 6 bu/ac more than the high ortho starter. But averaged over the 5 side-by-side comparisons, there was less than 1 bu/ac yield difference between the high and low ortho starters (P=0.6712).

In addition to finding no differences in grain yield between these two starters, the high ortho starters generally cost about $1 more per gallon (so $6/ac at a 6 gal/ac rate) than the low ortho starters. So the more expensive high ortho starter clearly did not “pay” its way in our 2016 field trial.

More Trials Planned for 2017

While our findings agree with other research-comparing ortho- and poly-phosphate starter fertilizers (Frazen and Gerwing. 1997), we want to be absolutely certain that our fertilizer offerings are the most economically viable products on the market. Therefore, I have decided to run this same field trial at one location in northern Illinois in 2017, and at one location in central Iowa in 2017. Stay tuned for those research results this fall.

Picture 1

Planting starter fertilizer trials near Traer, IA in the growing season of 2016.

Figure 1

5 side-by-side comparisons of corn yield from two 6-24-6 starter fertilizers that contained either 50% ortho & 50% poly-phosphate or 80% ortho and 20% poly-phosphate. The field trial was conducted near Traer, IA in the growing season of 2016.

References

Franzen D. and J. Gerwing. 2007. Effectiveness of using low rates of plant nutrients. North Central regional research publication No. 341. http://www.extension.umn.edu/agriculture/nutrient-management/fertilizer-management/docs/Feb-97-1.pdf (accessed 8 of Sept 2015).

Doctor in the Field

There’s a new doctor in the field. And by “field” we mean the corn field.

For the last two and a half years, Liqui-Grow’s Lead Agronomist, Jake Vossenkemper, has been working on his dissertation in Crop Sciences at the University of Illinois. Jake has been a PhD student since the spring of 2012.

On Monday, March 27, 2017, Jake gave his final defense for his dissertation on crop management factors that interact with soybean planting dates. Through his research, he found that soybean-planting date, seed treatments, and cultivar maturity selection are all-important management decision to consider for producing maximum soybean yields. He also found that warm fall temperatures can increase soybean yields by 3 to 6 bu/ac compared to normal fall temperatures. In addition, he found that when temperatures remain warm in the fall, full-maturity soybean varieties often out yield mid-maturity soybean varieties. These finding add to our understanding of what factors are important to maximizing soybean yields, and may help soybean breeders breed for resistance to cold late-season air temperatures.

We are all very proud and excited for Jake’s most recent accomplishment! He will graduate on May 13, 2017.​

ILeVO Seed Treatment: Just Another Added Expense, or Profitable Insurance Policy?

Jake Vossenkemper standing between rows of soybeans, one row treated with ILeVO and health, the other non-treated and sickly looking.

Research Summary:

  • SDS is a frequent disease of soybean, but it does not reduce yields every year—suggesting that ILeVO will be used as insurance-based management.
  • Using ILeVO increased yields in all 7 on-farm trials in the 2016 growing season.
  • The average yield increase across all 7 trials was 7.8 bu/ac resulting in net returns of $63/acre (Figure 1).
  • The economic optimum seeding rate averaged across these particular 7 locations was 127,000 seeds/ac, but seeding up to 140,000 only reduced partial profits by $2/ac—so it seems that over seeding is still cheap insurance against conditions that can significantly reduce stands.

Bar chart showing greater soybean yield in plots using ILeVO.Figure 1.

Average soybean yield for plots treated with base fungicide+Insectcide seed treatments and base fungcide+insecticide+ILeVO seed treatments at 7 on-farm sites in Illinois and Iowa in the growing season of 2016.

 

Introduction

Sudden Death Syndrome (SDS) is a fungal root rot of soybeans that can routinely cause reduced soybean yields in the U.S. Midwest. Soybeans are most susceptible to SDS within a few weeks after planting, presumably because it is easier for the SDS pathogen to penetrate young succulent root tissue vs. older root tissue that has had time to develop more ridged, less penetrable cortical tissue. Given this early season susceptibility, crop scientists have been searching for a seed-applied fungicide that controls the SDS pathogen.

Since about 2012, Bayer CropScience has been testing a seed-applied fungicide (a.i. fluopyram) that shows promise at reducing soybean SDS infection and yield losses associated with this disease. This seed-applied fungicide, as of the 2015 crop season, has been sold commercially under the trade name ILeVO. In addition to controlling SDS, the ILeVO that is treating the plants has also been shown to have fewer soybean cyst nematodes (SCN) per gram of root than plants with no ILeVO treating (Zaworski, 2014), and is currently being labelled for control of SCN.

Given that ILeVO controls SDS and SCN, this new seed treatment could dramatically increase soybean yields and provide significant financial benefits to Midwestern farmers when these diseases are at high enough levels to reduce yields. Since it is not always known, however, if these diseases will reduce yields at planting, ILeVO may be viewed as insurance-based management in the event that these diseases do reduce yields.

Another insurance policy that farmers have used over the decades is to plant more soybean seeds than necessary to produce maximum economic returns. Over seeding provides insurance against significant stand loss that can often occur from poor planting conditions or wet, cold soils that may materialize soon after planting. Recent research, however, shows that soybean economic optimum seeding rates (EOSR) may be as low as 100,500 seeds per acre when fungicide and insecticide seed treatments are used (Gasper et al., 2015), and is well below the current seeding rates that most Midwestern farmers use on their production acres.

Presented with the aforementioned information, it is possible that farmers may be able to reduce their current seeding rates in an effort to help pay for the added cost of the ILeVO ($10-to-$13/140k unit) seed treatment, in effect, trading dollars spent on an over seeding insurance policy for insurance against SDS and SCN.

To help answer these important economic questions, Liqui-Grow implemented some experiments in the 2016 growing seasons to investigate if the EOSR in on-farm trials is as low as some recent research suggests (100,500 seeds/acre), and to see how often buying an insurance policy against SDS and SCN (ILeVO) pays off.

Aerial photo showing difference between ILeVO-treated and non-treated plots.
Picture 2.
Visual difference between ILeVO-treated plots and base Fungicide+Insecticide. Green rows are treated with ILeVO.

 

The Applied Questions

  1. Is the EOSR as low as 100,500 seeds/acre in on-farm trials, and is the EOSR different for seeds treated with base fungicides+insecticide vs. base fungicides+insecticide+ILeVO?
  2. How often does ILeVO increase yields, and is the yield increase large enough to pay for the added cost of the ILeVO seed treatment?

How Were the Applied Questions Answered?

Four on-farm studies were implemented in eastern, IA and 3 in northern, IL. At each of these sites farmer cooperators seeded soybean at 50,000-to-150,000 seeds/acre in 25,000 seed increments. Half of each of these seeding rate plots were treated with base fungicides+an insecticide seed treatment. The remaining half of each of these seeding rate plots were treated with base fungicides+an insecticide+ILeVo seed treatments.

Plot widths ranged from 30-to-80 ft wide, and plot lengths ranged from 230-to-2,260 ft long. All sites were productive prairie-derived mollisols except for the Peoria, IL site; this site had sandy loam soils and was irrigated.

Calculating the EOSR

For calculating the EOSR, it was assumed that the seed cost was $82/140k unit for the base fungicides+insecticide treated seeds and $96/140k unit for the base fungicides+insecticide+ILeVo treated seeds. It was also assumed that farmers received $10 for each bushel of soybean sold.

All varieties used in these studies were Credenz brand soybeans marketed and sold by Bayer CropScience, and they had average to above average SDS tolerance ratings.

Results

At 6 of the 7 sites, SDS symptoms—chlorotic mottling and leaf chlorosis—were present during the seed-filing period (R6), and these symptoms were almost always more severe in the control plots that did not have seeds treated with ILeVO (Picture 1).

Averaged across seeding rates, yield increases for the ILeVO treated seeds ranged from 3.2-to-15.4 bu/acre (Table 1). Moreover, sites that had more severe SDS symptoms during the seed-filling period tended to have larger yield increases from adding ILeVO to the base fungicides+insecticide seed treatment package. An exception to this was the Clear Lake, IA site. At this site no SDS symptoms were visible during the seed-filling period, but on average ILeVO increased yields 5 bu/acre.

The EOSR for the base fungicides+insecticide seed treatments was 126,000 seeds/acre and the EOSR for the base fungicides+insecticide+ILeVO seed treatments was 128,000 seeds/acre averaged over the 7 sites (Figure 2). Moreover, the EOSR in these studies was about 25,000 seeds/acre higher than what the most recent published research suggests (Gasper et al., 2015).

Seed Treatment

LocationFung+InsectcideFung+Ins+ILeVO Yield IncreaseNet Return
 – – – – – – – – Grain Yield bu/ac – – – – – – – –$/ac
Walcott, IA52.255.43.218.8
Peoria, IL38.153.515.4136.3
Roseville, IL72.378.66.348.7
Walnut, IL59.472.513.1114.2
Clear Lake, IA78.183.15.036.2
West Liberty, IA48.453.24.834.1
Eldridge, IA64.871.66.853.5
Avg.59.066.87.863.1

Table 1.

Soybean yields and net returns from using base fungcide+Insectcide or base fungcide+Insectcide+ILeVO seed treatments at 7 Illinois and Iowa locations in the growing season of 2016.

 

Graph showing differential of partial profits being gained by using ILeVO with Fungicide and Insecticide rather than Fungicide and Insecticide by themselves.
Figure 2.
Soybean economic optimum seeding rates (yellow triangles) and the $2/ac range in partial profit (red circles) for seeds treated with base fungicide+Insectcide seed treatments and base fungcide+insecticide+ILeVO seed treatments averaged across 7 on-farm sites in Illinois and Iowa in the growing season of 2016.

 

Scatter Chart showing Soybean seeding rate vs Yield.
Figure 3.
Quadratic model for seeding rate vs. soybean yield for seeds treated with base fungicide+Insectcide seed treatments and base fungicide+insecticide+ILeVO seed treatments averaged across 7 on-farm sites in Illinois and Iowa in the growing season of 2016.

 

Conclusion

Averaged across these 7 sites, adding ILeVO to a base fungicide+Insectcide seed treatment package increased yields 7.8 bu/acre and economic returns $63.1/acre. This suggests that ILeVO may be a worthwhile insurance policy for farmers to purchase.

Even though there is not a guarantee that ILeVO will provide a return on investment in every season’s yield, increases such as these in 2016 suggest that ILeVO could be bought for the next 5 growing seasons and net returns would still be north of break even.

That being said, the odds are high SDS will return again in one or several of the next 5 growing seasons. While this specific data set does show that the EOSR is around 127,000 seeds/acre—still lower than the avg farmer seeding rate—it still may be a wise insurance policy to seed closer to 140,000 seeds/acre, given it is difficult to predict when significant stand loss will occur, and seeding 140,000 vs. 127,000 seeds/acre only lowered partial profits by $2 per acre in these studies.

References

Corn N Rec’s Using Nitrogen Management Models – Are they “Big League” Ready?

Overview

  • Can nitrogen models increase net revenues when compared to traditional N management rates? What about when compared to an N rate recommendation from the Corn N Rate Calculator? Several Midwestern land grant universities conducted a study to test this theory.
  • The nitrogen management model produced the lowest net revenues. These net revenues were $21. They were $27/acre lower than the net revenues produced by the growers’ traditional N management rates and the N rate recommended by the Corn N Rate Calculator.
  • While nitrogen management models may become more accurate with time, this study suggests that for now growers should proceed with caution before adopting N management models for wide-scale use.

Brief Introduction

Within the last few years, nitrogen management models seem to be all the rage. DuPont Pioneer promotes Encira Yield Nitrogen, Monsanto has Climate-N, and Agronomic Technology offers Adapt-N. This is a short list of the Big 3, but there are still the droves of Silicon Valley start-ups promising to solve all our nitrogen management woes.

The idea behind these N models is stellar: use less fertilizer N in years with low nitrogen loss conditions and more fertilizer N in years when more N loss has occurred. Potentially, this could reduce N pollution, save on fertilizer N costs, or increase yields in years when more fertilizer nitrogen is required.

This is, of course, the utopia for which the agricultural industry has been searching.

I am sure the aforementioned corporations have hired the best in the business to take on such a monumental task and that they are using the most advanced statistical models known to man. However, Mother Nature—and the complexities of the nitrogen cycle—will put up a formidable fight.

I can only hope that they have been successful. Answering these complex questions would be a win for farmers, for the agricultural industry, and for the general public. But are these nitrogen management models currently being sold to farmers ready for the “big league?” Can these nitrogen management models help farmers make better business decisions as soon as the 2017 crop season? The answer to that question still isn’t clear.

This past crop season, Liqui-Grow implemented experiments to give both us and our customers some clearer answers to this important question.

Applied Questions

  1. Can a nitrogen management model recommend an N rate that results in net profit gains compared to growers’ traditional N management rates?
  2. Can a nitrogen management model recommend an N rate that results in net profit gains compared to the Corn Nitrogen Rate Calculator developed by several Midwestern land grant universities?

Answering the Applied Questions

In southeast Iowa, nitrogen fertilizer rates ranging from 0-to-250 lbs of N/acre were applied to three different farmers’ fields. It was applied in approximately 50 lbs increments. In each of these three fields, these nitrogen rates were replicated 3 times. Soybeans were the previous crop for each field. Each N rate plot was 30 ft wide and approximately 300 ft long.

Most of the nitrogen was applied at the V-7 growth stage, dribbled on the soil surface as liquid UAN 32%. At each of these fields, the soils were highly productive, prairie derived mollisols with OM ranging from 3.3-to-3.8%.

At the request of the developer, the specific nitrogen model used will remain anonymous. It did, however, come from one of the Big 3.

The profitability from any N rate (or any N recommendation system) can be calculated by applying a wide range of N rates, as we did in these studies. Of course, this depends on the yield that any given N rate produced and the amount of nitrogen it took to produce that yield.

For the economic calculations, $0.39/pound of N was used. The price for a bushel of corn was assumed to be $3.50.

How Did the N Recommendation Systems Compare?

In the interest of being short and sweet, I will only discuss what happened on average across these three different trials. Nevertheless, I have included the results from each of the three locations in Table 1.

Therefore, on average, these three growers typically apply 170 lbs of N/ac when corn follows soybeans. The Nitrogen Rate Calculator, developed by several Midwestern land grant universities, recommended 149 lbs of N/ac, and the N model recommended 136 lbs of N/ac.

In spite of the growers applying 21 more lbs of N/ac than the N Rate Calculator recommendation, the yields between these two N rates were nearly identical. The grower-chosen N rate produced a yield of 230.4 bu/ac and the N Rate Calculator recommendation produced a yield of 229.6 bu/ac. The N model, however, recommends applying 34 and 13 less lbs of N/ac than the grower selected N rate and the N Rate Calculator recommendation. Therefore, the N model recommendation produced approximately 10 fewer bu of corn/ac than either the grower-selected N rate or the N Rate Calculator recommendation (Figure 1).​

The N model recommendations reduced the N cost by a few dollars/acre. However, the lost yield meant that the N model had the lowest net revenue, at $719/acre. The grower-selected N rate and the N Rate Calculator recommendations followed, producing net revenues of $740 and $746/acre.

Results

So, are these N models ready for the “big league?”

With the current commodity climate, I think most farmers will find it hard to gut an extra $27/acre, not to mention access to these N models is not free. No doubt, these N models will likely get more accurate with time. While that happens, however, this small investigation that evaluated only one of these N models would suggest that growers should proceed with caution.

Liqui-Grow will likely continue to evaluate these N management models, so stay tuned for further updates next fall.

Table 1.

Net revenue from grower-selected N rates, Corn N Rate Calculator recommended N rates, and an N rate prescribed by an N management model at 3 southeast Iowa locations in 2016.

Figure 1.

Nitrogen rates and corn yields at three different southeast Iowa locations in the growing season of 2016. Round markers represent the grower-selected N rates. Triangle markers represent the N rates prescribed by a nitrogen management model.