News

Potential Nitrogen Loss When Wheat Was Top-dressed With Urea or UAN

Questions have been coming into the lab about potential nitrogen loss from urea-based wheat top-dress applications made this spring. Many of these questions are being raised due to weather patterns around application timing.  Early spring applications were often followed by heavy rain fall, while late applications were followed by warm dry soils. While nitrogen loss is always difficult to predict, there are some basics taking place in these situations. To start, both dry urea and liquid UAN, which is 50% urea-based nitrogen, are subject to three nitrogen loss mechanisms, volatilization, denitrification, and leaching.

The naturally occurring urease enzyme in the soil converts urea into ammonium, the ammonium can be lost to the atmosphere as a gas during this process if the ammonium is not captured by the soil. Conditions that promote this are surface application on very dry or moist soil with delayed or light rainfall (less than 0.2”-0.3”, following application), heavy residue, and high humidity. These conditions impact dry materials greater than liquid, especially when the liquid is concentrated in bands. These low moisture situations can lead to the dry granule dissolving and not having enough moisture to move into the soil. Dry urea requires about 0.5” rain to incorporate into the soil where the urease released ammonium can be captured by the soil. Liquid UAN takes less rain to incorporate and even less when branded/streamed. Steady winds, delays between light moisture events, high soil pHs, and warm air temperatures above 70 degrees Fahrenheit will accelerate urea nitrogen loss to urease volatilization.

The next potential loss of nitrogen is from the rapid conversion of ammonium-nitrogen to nitrate-nitrogen that can be lost through leaching or denitrification. For urea-based nitrogen sources, the conversion of urea to ammonium is slowed by cold soil temperatures reducing the overall amount of ammonium nitrogen subject to conversion to nitrate that can be lost. For UAN half of the nitrogen is in ammonium or nitrate forms to start and can be subject to loss quicker than pure urea in dry forms. Short spells of warm weather can lead to rapid conversion of ammonium to nitrate. Warm saturated soils are needed for denitrification and leaching to occur.

Volatilization can be significantly reduced with the use of Agrotain (NBPT), which is commonly used on dry urea. Denitrification can be slowed greatly with the use of Instinct (nitropyrin), usually used with UAN to delay the conversion of ammonium to nitrate. Research has shown that ammonium thiosulfate is not as effective as these products but appears to have significant activity in reducing nitrogen loss by both mechanisms.

This Spring early season wheat top-dress had warmer soils, but the time periods of saturated soil were very short. There was some denitrification, it was most likely limited. Late applications were made to moist soils followed by low humidity dry weather with warm temperatures. Volatilization losses without the use of Agrotian or ammonium thiosulfate could have occurred where rain was limited, dry urea would have been at greater risk than streamed UAN. While conditions indicate that the loss was not excessive the use of soil nitrate and ammonium testing where the condition favored accelerated volatilization, along with wheat tissue tests, may be needed to monitor the crops’ nitrogen needs.

The ALGL Agronomy staff took their own advice and pulled a couple of nitrate samples. Streamed UAN with ammonium thiosulfate and nitropyrin in late application made before a dry spell with low humidity on soil with an elevated pH resulted in approximately a 7% nitrogen loss two weeks after application in the Fort Wayne area. More information on making these determinations cab be found on our blog post "Making Sense of Soil Nitrate and Ammonium Values."

What's in Your Tank?

Not that long ago, creeks, rivers, and ponds were an acceptable source of spray water. This practice seems unthinkable today, given our understanding that products like glyphosate are rendered inactive by clay particles and other impurities in the water. Through research it has been demonstrated that most pesticide chemistries are impacted, often negatively, by the various dissolved minerals and pH of the water used as the carrier.

Weed resistance, rising input costs, the need for effective cover crop kills, increased use of companion products such as foliar fertilizers, along with an increase in spray solution modifying adjuvants reaching the market have increased the need to quantify the quality of water used for pesticide dilution. Currently it is more common to analyze spray water quality after something has gone wrong rather than proactively testing to identify potential problems. 

The stability of pesticides in the spray tank is often directly tied to the pH and the presence of dissolved minerals in the spray water. Depending on the pesticide chemical formulation, the active ingredient can be rendered inactive by either reacting with hydroxyl groups at high pH or with additional hydrogen ions at low pH. These chemical alterations of the active ingredient can also drive chemical reactions with the dissolved solids in the water rendering the pesticide inactive.

Herbicide products like dicamba and 2-4,D amine can be unstable at pH’s above 7.0. Insecticides and fungicides are even more sensitive to spray water pH.  For example, some can be stable in the spray tank for days to months at a water pH of around 5, while at a pH of 9.0 are stable for only minutes. Many of your brand name pesticides that are pH sensitive are buffered in the formulation; however, this is not the case for all generics. Adjuvant manufactures have been addressing this need with a wide array of spray water modifiers to buffer pH concerns and tie up dissolved minerals before they impact the pesticide performance.

Analysis of your spray water will greatly improve the success in identifying the right adjuvant and using the product at the correct rate. The use of ammonium sulfate (AMS) with glyphosate applications is a good example of this. When spraying glyphosate, the label rate for AMS is 8.5 to 17 pounds per 100 gallon of spray water. By testing your spray water, you can pinpoint the rate needed for the application, possibly saving on the cost of excessive AMS while still ensuring adequate product to protect the efficacy of the glyphosate. If you are interested in seeing where your spray water stands, please contact the lab for sampling kits and for more information.

Predictions for Nitrogen from Fall-Applied Sources

The nearly perfect weather conditions during the fall of 2022 lead to one of the most efficient harvest seasons in recent memory. The dry soil conditions provided the opportunity for many producers to apply manure or anhydrous ammonia earlier and on more acres than they would in an average year. Now with planting underway throughout much of the region, growers are beginning to question how much of the nitrogen is still there.

An ideal scenario for retaining fall applied nitrogen is a winter that starts off cold and stays cold with relatively low precipitation. Unfortunately, that was not the case for most of the Eastern Corn Belt. Through the months of February and March, the temperatures were a roller coaster. This is very obvious when viewing the National Weather Service’s monthly ice and snow report for February 2023. Fortunately, we did not have excessive precipitation during this time, but most areas still saw average to slightly above average precipitation. So, what does this mean for nitrogen retention? It means that much of our region has had the potential to experience significant nitrogen loss since last fall. Soil testing for nitrate and ammonium is going to be critical this season for those fields with fall applications. For more information on potential winter losses of nitrogen please visit our article  from last spring.

Pelletized Lime vs. Ag Lime

The agronomy staff at ALGL is often asked what are the differences between pelletized lime and regular ag lime? Which one is better? Which one should I use? Is pelletized lime worth the extra cost?

Let’s start with the similarities between pelletized and al lime. Both forms of lime are a mixture of calcium carbonate and magnesium carbonate. The amount of calcium and magnesium vary based on the limestone mineralogy from which the material was mined. Both forms neutralize acidity through the same chemical reaction.

The differences between the two are the physical properties of each. Ag lime is simply crushed limestone and is comprised of particle sizes ranging from a fine powder to small pieces of gravel. For the lime to work, it must dissolve in the soil solution. The smaller the lime particle, the faster it dissolves and begins to neutralize the acidy. The benefit of having various particle sizes is that the small particles will start the process and the larger particles will continue to work for several years.

Pelletized lime is very finely ground limestone that is mixed with a binding agent and pressed into spherical pellets. The concept behind this is to produce a lime with the ability to react quickly but is easy to apply since it can be spread with any equipment used for spreading traditional fertilizer products.

One of the misconceptions about pelletized lime is that you get the same results as ag lime while using only a fraction of the amount. In the short term, this may be true since it does react faster, but it will also run out much faster. So, over the course of several years, it will take the same amount of lime to manage the soil pH, it just needs to be applied at lower rates more frequently. Typical application rates for pelletized lime usually do not exceed 500 pounds per acre and may only be effective for 1 to 2 years. Whereas an application of ag lime may be as high as 3 to 4 tons per acre in a single application and may effectively manage the pH for 4 to 8 years.

For large scale lime applications, it is hard to justify the additional cost of pelletized lime to completely replace traditional ag lime. However, pelletized lime does have its place in pH management. For small fields and wildlife food plots, where access prohibits a large lime spreader, it is a great fit. For land that may only be secured by a grower for a short period, pelletized lime may provide a short term improvement in soil pH without the long term investment of ag lime. Pelletized lime can also be blended with other fertilizers and be spread in a single application when only a low rate of lime is needed.

When it comes to deciding which form of lime to use, it is not about which form is better than the other. Pelletized lime and ag lime are both good products. It is about selecting the form that fits the situation in which it is being used.

Starter Fertilizer and Crop Injury Potential

Starter fertilizer can be an important part of a crop fertilization program when managed properly.  Nutrients placed in close proximity to the developing plant are readily available for uptake.  Early plant development and crop uniformity is encouraged, which can lead to increased yield and/or lower harvest moisture.   However, there are potential injury risks associated with starter fertilizer that must be managed.

Virtually all fertilizer materials are salts and they need to salts to become plant Available. When they dissolve in the soil they increase the salt concentration of the soil solution.  An increase in salt concentration increases the osmotic potential of the soil solution.  The higher the osmotic potential of a solution, the more difficult it is for seeds or plants to extract soil water they need for normal growth. When a fertilizer referred to as a “low salt fertilizer” it is not that fertilizer has less salt, it means the fertilizer has a low index or low salt impact.

Renewed interest in placing fertilizer in or close to the seed row makes it important to remember that an increase in salt concentration in the fertilizer band can cause seed and seedling injury.  Placing fertilizer at least two inches away from the seed can usually prevent injury.  Excess fertilizer application in a starter band can still produce injury, especially under dry conditions.

The accompanying table shows starter fertilizer application method and rate guidelines from Purdue University.  It should be recognized that these are for “typical” growing conditions.

 Fertilizer Placement and Rate Guidelines - Corn

 2x2 Placement – banded 2” beside and 2” below the seed 

• Sandy soils - maximum of 30 lbs N+K₂O
• Heavier soils - maximum of 60 lbs N+K₂O

 Seed-row – applied in furrow, directly on seed. 

• Sandy soils - maximum of 5 lbs N+K₂O
• Heavier soils - maximum of 8 lbs N+K₂O

 Although university guidelines in the region don’t directly mention sulfur (S), it is a salt and should be included (N+K₂O+S) so that the amount applied does not exceed the limit shown in the table.

 Care should be taken when applying fertilizers (urea, MAP, DAP, UAN, ammonium sulfate, ammonium thiosulfate) that produce free NH₃ in direct seed contact.  Soybeans are especially sensitive, and seed row placement of fertilizer should only be done with extreme caution.

The addition of micronutrients in starters should also be done with caution. Elements like boron, copper, and zinc can be toxic to plants in high concentrations. While the safety tolerance on zinc is quite high, boron and copper can create zones of potentially toxic levels when high rates are concentrated in a band close to the row. This is of greater concern in heavier soils with poor drainage. For example, a common annual broadcast application rate of boron is 0.5 to 1.0 pounds per acre. If that same rate was applied in a 2x2 it would effectively increase the concentration of boron in the band 10 to 30 fold. A 10 pound per acre rate of boron would be toxic to most crops.

A great detailed reference on fertilizer salt index can be found at: https://extension.soils.wisc.edu/wcmc/understanding-salt-index-of-fertilizers-2/

Impact of Manure on Soil pH

A growing issue in the portions of our region is manure applications leading to unexpected or undesirable increases in soil pH. The secondary challenge is that once this issue is identified, and manure applications have been stopped, the soil pH will continue to increase for several more years.

This situation arises with the use of sand bedded dairy manure or layer poultry litter. Often the sand used to bed dairy cows is not actually silica sand, rather limestone (calcium/magnesium carbonate) sand. Any sand passing through separation processes functions the same as course lime.

Layer chicken flocks have calcium carbonate added to their diets to support eggshell formation and avoid calcium deficiencies in the hens. The excess calcium carbonate passes through the digestive track of the bird and feed waste is added to the layer litter. Broken eggs can also be in the litter from accidental breaks in the layer barn. If the layer operation produces liquid egg materials, the eggshells are often added back into the layer litter for land application.

The bedding sand, calcium carbonate feed additive, and eggshells are slow to dissolve and increase soil pH. It often goes un-noticed for several years of application. However once the rise in soil pH is noted, the soil pH will continue to increase for several years after application of the materials has stopped.

The pH increase of these materials is also a very useful tool when used on low pH soils. To better estimate the impact of these manures on soil pH we can test the manures for CCE (calcium carbonate equivalent) the same as a ag lime. While the interpretation of the CCE data is not defined, it does give a relative understanding how quickly and severely the soil pH might increase. For more information on testing the CCE of manures, contact your ALGL regional agronomist.

Calendar Time Again!

The ALGL customer phot calendar is becoming a tradition! This past year we celebrated the 6^th issue of the calendar built by you. The calendar is slowly becoming a tradition. Once again, we are reaching out to the best customers a business can ask for.

 Do You have photos to share?  Please share with us pictures of those things in the life sciences that speak to you and show how amazing the world around us truly is. We want to see pictures that illustrate what fuels your passion for life sciences and customer service. When you get that picture captured, send it to news@algreatlakes.com along with your name, address, and brief note about the picture(s). Please submit your pictures in the highest resolution possible before September 15th. Then we will select our favorite pictures, then we will be letting our followers on Facebook vote on their favorite, to be on the cover of the 2024 calendar. Follow us on Facebook for voting details.

 Photo criteria 

• Landscape oriented photos preferred, but not required.
• Please do not crop the pictures before submission.
• Please share the highest possible resolution photo.
• Please try to avoid company logos and easily identifiable faces.
• No dangerous or illegal activities.

Rules 

• Photo submission deadline is September 15, 2023
• One entry per person, however you may submit more than one photo.
• Must be 18 years or older to enter.
• Need not be present to win.
• No purchase necessary.
• Submitting a photo gives A&L Great Lakes permission to use the photo for promotional use.
• Employees of A&L Great Lakes Laboratories, Inc. and their immediate families are not eligible for prizes, but may submit photos for consideration in the calendar.
• Use of images in promotional items does not increase your odds of winning a prize.
• Contest decisions and/or judgements by A&L Great Lakes Laboratories, Inc. are final.

Is it M3 or Bray?

With the transition of Indiana, Michigan and Ohio university fertilizer recommendations moving to Mehlich 3 (M3) data the question of, “How do you tell if the ALGL soil test results are in M3 or Bray-P/AA-K?” comes up often.

Internally we refer to the grouping of Bray-P, ammonium acetate (AA) K/Ca/Mg/S/Na, hydrochloric acid (HCl) Mn/Fe/Cu/Zn, and hot water (HW) B as NCR or North Central Region. From a soil testing perspective, the country is divided into regions based on the soil characteristics in that region. Researchers in those regions have identified the tests that are appropriate for the soils and climate of the region. While M3 it utilized by almost all regions of the country, the traditional methods of AA, HCl, and HW are also appropriate for most of the corn belt.

ALGL publishes over 50 different report formats to meet customer needs that vary in appearance. Reports that show M3 values will have “M3” in the column header for that nutrient. If “M3” is in not in the column header for that nutrient the value reflects NCR methods. This does not apply to pH or OM. The values displayed on the report are those used to calculate the CEC and cation saturation percentages.

When looking at electronic data files for uploading to software, this may not be as clear depending on the software used. Some uploads for software do not identify the units nor the method for each column of data. If unsure, your ALGL regional agronomist can help.

Carbon to Nitrogen Ratio and the Microbes in Your Soil

In today’s agricultural media, there is a lot of emphasis on soil health, soil biology, and soil carbon. These topics are all interrelated. Whether your goal is the improve the structure of your soil, increase the natural nutrient cycling from one crop residue to the next, or build your bank of soil carbon, the soil microbes need a steady feed source of carbon-based material to carry out these functions. However, not all materials are equal.

One of the best measurements to determine whether or not a material is easily decomposable is the carbon to nitrogen ratio (C:N). Microbes are most easily able to decompose material with a C:N around 25:1. At this level, the microbes can utilize the carbon converting most of it to carbon dioxide leaving behind soil organic matter that has a C:N of about 10:1. The microbes will continue to decompose the remaining soil organic matter, but at a slower and slower rate due to the complexity of the molecular structures that are formed.

The most common form of carbon inputs is the crop residue that remains after harvest. Soybean residue has a C:N of about 25:1, meaning it can be easily decomposed. Corn and wheat residue can have a C:N ranging from 50:1 to 100:1. While these residues are a great source of building carbon, the microbes will compete with your next growing crop for available nitrogen potentially inducing a nitrogen deficiency. Other common carbon inputs are manures. Most manures  have C:N around 5:1 to 20:1 which means that there is more than adequate nitrogen for the microbes to utilize while releasing the excess for a growing crop to use. Manures with a high volume of bedding materials such as straw or wood shaving should be tested to ensure that they will not cause a nitrogen deficiency.

Most cover crops have desirable C:N for easy decomposition. However, grasses will have high carbon content than legumes, brassicas, etc. and may require adjusting a nitrogen program for the following commercial crop.

The Value of Meeting in Person – A Sales Perspective

By Jamie Bultemeier - Corporate Sales Director

As the winter professional meeting and trade show season is in full swing, I am constantly thinking about the value of the time and expense versus the return from these events.

Over my 20 plus years in the industry the impact and focus of industry trade shows has changed, and conversations are different. The existing customers are still wanting to discuss current topics, however the time window of the current topics has narrowed. Today customers are not waiting the next trade show to discuss a topic. Usually they are calling, emailing, or texting within a few minutes to a few days of when the thought arose. The business growth conversations are more in depth and private today that does not lend itself to a public conversation at a trade show. The prospective customer looking for a product or service has been replaced with individuals searching for ideas and options, or information in addition to what they have discovered in an internet search. Again, that window has become narrower as the client or potential client is likely to call, email, or text long before the next trade show. The conversations at the events are becoming more personal, and philosophical, which leads to a much deeper understanding of our customers and industry partners.

Information is flowing at a much faster rate. So why incur the expense and commit the time to these activities as a business? The Covid pandemic has taught all of us that personal contact and communication is difficult at best to assign a value to. Yes, virtual events and internet searches are a great way to transfer and receive basic information quickly, but it loses the focus, concentration, and collaboration that meeting in person brings. The key aspect non-verbal communication is lost by not meeting in person. Many of the conversations had at these meetings may never take place if not facilitated by the event being attended.

The dynamics of these events has changed. We may not leave the event with as many direct sales leads as we did in the past, but we leave with an expanded and better developed network of contacts that is constantly growing and will lead to the sales growth if nurtured. Agriculture is still very much a relationship-based industry. If we recognize the changes in these events over time and modify our approach to them, the sales will come, they will just take a slightly different route to materialize.