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Fertility Components Critical For High Yield Corn

Nitrogen. Multiple applications of N are more efficient and result in higher yields (preplant, starter, pre-tassel applications through pivot or sidedress, and post-tassel applications). Additionally, multiple applications improved N use efficiency and reduce potential for stalk rot organisms to infect corn stalks.

Post Tassel N Applications.
Post-tassel (post-flowering) applications of N can increase yields by increasing kernel depth and test weight. In Dupont/Pioneer research, applying a significant portion of the applied N at brown silk averaged 31 bu/a more than applying all N before tassel. Modern hybrids can respond well up to 33 percent of N rate goal going on between brown silk and dough stage. Recent Purdue research has shown that the newest corn hybrids use more N post-tassel than the hybrids of several years ago.

Russel French, Robert Bowling and Alyssa Abbott – Dupont/Pioneer

(continued, view and download below)

Storage and Handling Characteristics Of Ammonium Polyphosphate Solution

Ammonium polyphosphate solution (APP, 10-34-0, 11-37-0) is the most common liquid P fertilizer material in the U.S. today.  While 10-34-0 is the most common grade of APP solution, 11-37-0 is also found in some markets. While the following comments reference 10-34-0, most comments are applicable to 11-37-0 as well. The only real differences will be density, salt-out temperature and water content. While APP solution can commonly be found throughout the fertilizer industry, proper storage and handling techniques are not always followed at the retail level.  As a result, it is far too common to hear of storage problems associated with APP solution.  Grayish-brown and white precipitates at the bottom of the tank, cottage cheese-like particles floating in the product and slimy, stringy masses throughout the product are all evidence of storage problems associated with APP solution and/or other grades made with APP solution.

Most of the APP solution produced today is made by the pipe reactor process.  In this process, wet-process superphosphoric acid and anhydrous ammonia are reacted in a “pipe” to produce a melt that has a temperature of 600° F to 700° F and a polyphosphate content of 70% to 75%.  After the initial reaction in the pipe, the melt must be rapidly cooled, diluted with water, and further neutralized with ammonia to maintain the high polyphosphate content and resultant high quality.  At the time of manufacturing, the APP solution  should have the following properties (approximate, may vary):   ……..   (continued, view and download below)

The Value and Impact Of FFF Research

Wow! What a program at the recent Fluid Forum held in Scottsdale this past February. While we sometimes hear that there really isn’t anything new in crop nutrition anymore and that we are often funding ‘more of the same’ research – the research updates presented at the Fluid Forum say otherwise.


From research trying to better understand why we now consistently observe potassium responses on soils with potassium soil test levels far above what we previously considered fully adequate – to research delaying part of the overall nitrogen program for application after tasseling for corn. The results of both these research projects fly in the face of conventional wisdom in the not too distant past.


In addition, other research updates ranged from topics delving into the intricacies of identifying the interaction of soybean genetic yield gain and the need for supplying additional fertilizer nitrogen – to assessing the potential for drip Irrigation in the timing of nutrient availability for most efficient nutrient utilization. Neither of these research projects are ‘more of the same’ research! The remaining projects and research updates were likewise ‘cutting edge’ and not a repeat of past research.


What these projects point out is that the forward looking research funded by the Fluid Fertilizer Foundation is extremely important as all of agriculture continues to face change. Additionally, as the industry continues to embrace the 4R concept of nutrient management – it becomes more and more evident that fluid fertilizers are more often than not the right source once the questions of the right place, right time and right rate are answered.  And it also becomes more and more apparent that the research funded by the Fluid Fertilizer Foundation is needed more now than at any time in our industry’s past.

At the Fluid Forum this past February, Dr. Paul Fixen with IPNI was asked to review the impact of the past 35 years of our efforts  in nutrient management – and to speculate on what is next for our industry. One of the key take home messages I had from his remarks was that we need take credit for all the progress we as an industry have made over the past 35 years, to let everyone know of this remarkable progress and to focus on what we have solved ….. and not on what is not perfect.  Too often we focus on the glass being half-empty rather than the fact that that the glass is actually half-full.


Large, consistent improvements in crop yields, remarkable improvements in nutrient use efficiency and marked reductions in soil erosion are just a few examples of this progress. But too often we compare where we are now in 2017 with what a perfect crop production system might look like – and we find that we are not perfect. Indeed, predicting nutrient management needs for an individual field in an individual year is hard, if not impossible!


As we look to the future and develop our plans for meeting future challenges and changes, let’s make sure that we remember that past research such as historically sponsored by the Fluid Fertilizer Foundation has provided the foundation for dealing with the change and opportunities facing all of us today. Likewise, the forward looking research presented at the 2017 Fluid Forum is laying the groundwork for the challenges and opportunities of tomorrow. I can’t hardly wait for the 2018 Fluid Forum!


Dale F. Leikam


Fluid Fertilizer Foundation

Soil Nutrient Levels Can Be A Concern On Newly Acquired Land

(The following article recently appeared in a PotashCorp ‘field reports’ bulletin, Fall 2016)

Changes Expected With Rented Farmland

Kelvin Leibold, Iowa State University Extension farm management specialist, focuses his efforts on North Central Iowa, where between 61 to 70 percent of all farmland is rented.  “Last year, there were a few farmers in our area that had to reorganize and let rented farmland go,” he says.  “I expect twice as much this year.”

Michael Boehlje, a distinguished professor of agricultural economics at Purdue University, also expects farmers to exit due to age or the downturn in the agricultural sector.  “Over the past few years, some farmers have delayed exiting the business due to higher prices,” he says.  “However, we expect a turn in the rental market for the upcoming growing season.”

Managing Newly Acquired Land

This shift could provide an opportunity for farmers who have had difficulty renting new ground in the past two to four years to expand their operations.  Boehlje says farmers interested in expanding their operations should already be thinking about how they want to proceed.

Farmers renting new ground should do research on soil fertility levels in their area when they are determining rental bids.  As a way to cut costs, the previous operator might have drawn down the soil P and K levels versus building up soil fertility levels – especially if they were uncertain of how long they would be farming the ground.

While many farm leases have provisions about soil fertility in them, Kevin Leibold, Iowa State University Extension farm management specialist, says some renters might not be adhering to them.

“Farmers are expected to apply nutrients to replace what their crops remove,” Leibold says.  “But in reality, I am not sure it is happening.”

Tim Smith, managing agronomist for Cropsmith based in Monticello, Illinois, says soil nutrient levels in his area have likely been reduced since yields have exceeded their fertilized yield targets.

“Soil tests are a very inexpensive way to monitor nutrients and pH levels,” he says.  “Farmers should use soil testing as a guideline and look at soil tests over time.”

Overall, it is important to focus on trends rather than the absolute numbers in the soil test.  For example, if a nutrient is trending downward, he says farmers should discuss the need for corrective management options with their retail agronomist.

To help retailers and farmers determine their fertilizer rates on any newly rented land, PotashCorp offers a number of tools and resources such as the Nutrient ROI Calculator 2.0 and a Nutrient Removal Calculator on the eKonomics website.

Source: PotashCorp

Nitrogen Applications For High Yield Soybeans

Results from a two-year (mid 1990’s) Kansas State University study at four irrigated sites in Kansas show that late-season application of N to soybeans at the R3 growth stage will increase soybean yields. These results, coupled with similar results in other  states, suggested that retail input suppliers, public and private labs and consultants who make fertilizer recommendations should consider N applications on irrigated soybeans with high-yield potential. Six of the eight site-years were responsive and showed an average soybean yield increase of 6.9 bu/A or 11.8 percent with late-season N fertilization. Yields at these six sites ranged from a low of 56 bu/A to a high of 83 bu/A. The researcher concluded  that producers of high yielding soybeans (greater than 55 bu/A) would benefit from a late-season application of N at the 20-lb/A rate of N.

Fast forward to 2016 where University of Delaware researchers arrived at very similar conclusions. These researchers found that application of supplemental N may provide a yield benefit for high-yield soybeans, but only in cases where expected yields are 60 to 70 bu/A or higher. In summing up their research, they concluded that Growers are unlikely to see yield increases from late-season (R3) supplemental fertilizer N in situations where yields are not likely to exceed 60 bu/A. In production scenarios where yields are likely to be less than 60 bu/A, application of supplemental N is more likely to result in unnecessary expense and increased environmental impact.

Access Kansas State University Fluid Journal Soybean N article

Access University of Delaware Fluid Journal Soybean N article

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Ammonium Sulfate and UAN Solution Blends

Depending on the supply of ammonium thiosulfate (ATS, 12-0-0-26S) at times and the purchase price differential between ammonium sulfate and ATS, there are sometimes inquiries made about substituting ammonium sulfate for ATS in blending with UAN solution. Ammonium thiosulfate is a preferred source of sulfur in clear solution fertilizers because it allows for much higher nutrient analysis in finished blends than ammonium sulfate. Ammonium sulfate (i.e. 8-0-0-9S solution and 21-0-0-0-24S dry) has not been used much in solution fertilizers in the past because of the lower grades that are possible – especially if potassium chloride is included in the blend.

It is possible to make an 8.7-0-0-10S solution that has a salt-out temperature of about 32°F. However, the common grade of ammonium sulfate solution found in the market is 8-0-0-9S and is commonly used as a water conditioner for herbicide applications. Generally, 32% UAN solution and ammonium sulfate solution are compatible in any proportion. Table 1 provides information on various 8.7-0-0-10S and 32% UAN solutions that have a salt-out temperature of about 32°F. If 28% UAN and/or 8-0-0-9S solution is used, the resulting blends will have a salt-out temperature of less than 32°F.


Table 2 shows several blends made from dry ammonium sulfate (21-0-0-24S), 32% UAN solution and water. For those with limited experience in formulating liquid fertilizers, keep in mind that dissolving ammonium sulfate to produce these blends is different than adding ammonium sulfate to your glyphosate herbicide mixes. Efficiently solubilizing dry ammonium sulfate in UAN solution and water requires adequate agitation, water/UAN temperature of 50-60°F or greater and adequate equipment.


Tables 3 contains several properties of various ammonium sulfate solution grades while Table 4 details the negative heats of solution of ammonium sulfate, urea, ammonium nitrate and potassium chloride when dissolved in water. The greater the negative heat of solution and the greater the heat requirement to dissolve the various salts in water.


Density of Fluid Fertilizers

temp-vs-densityKnowing the specific gravity ( density) of fluid fertilizers is very important for accurately applying the correct rate of fluid crop nutrients. So where can we find a table or chart that presents the densities of various fluid fertilizers and blends? While there is information detailing the characteristics of common fluid fertilizers, we need to keep in mind that this information provides typical values only and will vary depending on such things as the raw materials used, impurities in the product, temperature, storage conditions and other factors. These ‘table values’ are ballpark values only – they should be checked for your specific product. Also, there are an infinite number of fluid blends that can be made from common fluid fertilizers – and there are no ‘table values’ for these individual blends.  The density of each blend should be determined.

How can density be measured in the field? The best way is to use a hydrometer. A hydrometer is an instrument typically made of glass that measures the specific gravity of fluids. If a hydrometer is not available, a  simple method is to fill any container with water and weigh it – taking into account weight of container. Then repeat with the liquid fertilizer and compare its weight to the weight of the water. By comparing these weights you can determine the specific gravity and hence the density of the liquid.

Specific Gravity of Fertilizer   =       Weight of fertilizer /  Weight of water

Density of Fertilizer (lbs/gal)   =      Specific Gravity of fertilizer   X   8.34

For example –->  assume a 5 gallon pail of water weighed 42.7 pounds after subtracting out the weight of the pail. When filled with 28% UAN, the weight of the fertilizer was 53.4 pounds.

Specific Gravity of UAN      =     53.4 / 42.7    =   1.28
.      Density of UAN             =     1.28 x 8.34    =   10.67 lb/gal

See Technical Article on Fluid Fertilizer Density

Specific Gravity and pH Variability Affect UAN Blending

Urea-ammonium nitrate solution (UAN) Variations in pH and specific gravity can wreak havoc on your UAN blending processes.  Reasons for the variations vary, but it is prudent to be aware of what you are dealing with so that you can produce a viable end product.

Nitrogen production begins with the re-formation of natural gas to produce ammonia, thus natural gas constitutes 70% of the cost of ammonia production.  Ammonia then is cracked and further made into nitric acid and other nitrogen products such as urea and ammonium nitrate; this makes natural gas one of the raw, precursor molecules for all nitrogen materials, providing the hydrogen.  This process applies to both liquid and dry nitrogen products, but in this discussion we are addressing the urea ammonium nitrate (UAN) combinations which have seen an increased demand in liquid markets.

What has occurred since the 1980s is that domestic natural gas prices have increased in cyclical swings which at times increased significantly the cost of all nitrogen related materials, including UAN.  This was further compounded by extremely low cost natural gas in many other parts of the global economy.  In the last 30 years, many of the major nitrogen producers acquired smaller companies and, due to those higher natural gas costs, then closed or moth-balled the smaller, less efficient production facilities, significantly decreasing North American nitrogen production.  Due to less domestic production, import nitrogen materials have continued to increase and today are well over 50% of our total nitrogen consumption.  It has only been in the last few years, due to major reserves being located throughout the northern tier of the United States, that natural gas prices have fallen low enough to start discussions on the building of new nitrogen facilities in North America.

With the loss of production and production personnel due to retirement and an increased volume of solutions being imported on the international market, we are seeing observable variations in the ratios of urea to ammonium nitrate.  It is fairly common for import UAN to be of higher analysis than 32%, sometimes lower.   It is sometimes being cut with water, but this is not a refined application so there are observable variations in pH and gravity from transfer from ships and transfer equipment to dealers.  In some cases, the addition of anhydrous ammonia is used to meet grade or possibly as a corrosion inhibitor.**  The problem that is created by the addition of free ammonia to meet grade or for corrosion inhibition is that there are observable broader ranges of pH in all products of UAN produced.  In addition, there are also broader ratios of urea to ammonium nitrate, depending upon producer.

One major liquid fertilizer product mixed with UAN is ammonium polyphosphate (APP) as either 10-34-0 or 11-37-0.  The blending of these two components tends to be done in the early to mid part of the growing season.  What has been observed over the last decade are continued cases of solidification of these two materials when co-mingled in several typical fertilizer blends.  In all cases that have been studied where individual components UAN and APP could be tested individually, it has been found that the pH of UAN is higher than typical MSDS data sheets indicate.  In that time span, UAN has been tested and found to have a pH range of from 6.8 to 9.2.

While the production of UAN and formulation of UAN and analysis can be reached by a number of different ways through nitrogen ratio addition products, the products that UAN may be blended with do not allow for such significant ranges in pH.  This is true not only of mixing with ammonium polyphosphates but with some minor nutrient components as well.  It is recommended that when receiving UAN, two tests should be used to determine potential issues with UAN usages in blending, especially in early spring weather.  The first is the use of a hydrometer to check specific gravity for concentration, and the second is testing the pH within some relative degree of accuracy for blending compatibility.  This important information allows the user to be aware of variations in advance so that adjustment can be made for grade or when co-mingling certain other products.

The following is a picture of a tank manway from spring of 2012 that was opened within a few hours of blending UAN and polyphosphate and was then not flowable enough to be pumped out of the tank.  As is seen in the picture, these two products solidified quickly.  This tends to happen more often at the first to mid part of the planting season when dealers are receiving loads of material that are not being mixed with other volumes but almost immediately being blended and going to the field for application.  One recommendation may be to allow enough volumes to be laid into storage to allow for pH and slight gravity variations.

Orr Manway

Variations in the formulation of UAN have been on-going since the inception of the process.  It seems to occur more often with unseasoned personnel or when not enough volume is in the storage tanks to minimize ratio variations and/or free ammonia and product is shipped out immediately.  In the past, some manufacturers of UAN have, in fact, had UAN summer blends and UAN winter blends, seasonally altering the ratios of urea to ammonium nitrate.  When one thinks about that, the product is relative to the location of the facility involved, whether it is located in a northern climate or a southern one.  Take time to familiarize yourself with the product you are receiving.

Another factor affecting UAN-APP compatibility is simply the overall solubility when UAN and APP are directly blended together (no additional water), especially during times of the year when product and air temperatures are cold.  While UAN and APP are generally thought of as completely compatible, the solubility of the UAN-APP system is drastically affected by the ratio of UAN to APP in the blend. Figure 6 presents the UAN-APP-KCl solubility diagram developed by the National Fertilizer Development Center (NFDC-TVA) during the early years of the fluid industry. The portion of the graph circled in green (left side of triangular diagram) illustrates that total nutrient solubility (N + P2O5 + K2O) decreases drastically as the proportion of UAN increases in UAN-APP mixes while the potential for precipitation formation increases (forming less soluble ammonium tri-polyphosphates). This problem rarely occurs when 28 percent UAN is used for these mixes rather than 32 percent UAN and occurs more frequently for 11-37-0 APP than for 10-34-0 APP. Previously discussed variations in UAN product analysis, pH and urea:ammonium nitrate ratio makeup further increase the potential for unanticipated compatibility issues.

UAN APP Solubility

This  information not to point blame or liability, it is for education and understanding for all dealers and wholesalers to better understand the problematic issues that can occur with even the simplest blending of UAN and polyphosphates.

See Fluid Journal Article

Why Fluids?

Top 10 lists are ever popular in our culture today – so what are the top 10 advantages of fluid fertilizers? Ask a handful of farmers and dealers and you likely will come up with a handful of different answers.

There are so many, and the advantages so varied, that it is not possible to come up with a single top 10 list that everyone can agree to! Some advantages benefit everyone. For others their appeal depends on the specific situation involved.

Typical benefits noted include things such as: a wide variety of fertilizer placements, homogeneous blends, best adapted for split applications, high nutrient use efficiency, handling conveniences, provides environmental benefits, required for fertigation, best suited for variable rate application, and many other benefits that give fluids a distinct economic appeal.

While it is not possible to name the definitive top 10 benefits of fluids that apply in all situations, my top five benefits of fluid fertilizers should broadly fit most everyone. A more in-depth discussion of each of these benefits will be presented in future issues of the Fluid Journal

……………..  click below for full text …………………

Why Fluids pdf