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Nitrate losses through leaching and denitrification, and the soil’s ability to supply nitrogen through mineralization of organic matter, are probably the two largest variables in selecting the best nitrogen application rates for corn production. Temperature and moisture are the controlling factors that drive these processes and, while the weather is beyond our control, nitrate and ammonium soil testing are valuable tools that can guide us to better management decisions. When compared to traditional soil sampling for nutrient content please consider some critical process changes that need to be made when analyzing for nitrate and ammonium. Soil cores must be taken at a depth of 0”-12” and it is best to collect 15-20 cores per sample because of the higher variability of nitrogen content across the landscape. The samples must be shipped to the lab as quickly as possible (1-2 days) for best results.
Results are normally reported as NO3-N (nitrate-nitrogen) and NH4-N (ammonium-nitrogen) measured as a concentration in parts per million. While these samples have been analyzed for the nitrate and ammonium compounds, the results have been converted by calculation to reflect the actual nitrogen content of each nitrogen form, and they can be added together to estimate the combined nitrogen. Please remember that the results are based on a 12” sample and must be multiplied by 4 to estimate nitrogen in pounds per acre. Additional samples can be collected from deeper in the soil profile (12”-24” and 24”-36”) to track mobile nitrate which can leach downward with soil moisture.
Jim Camberato and Robert Neilsen with Purdue Extension have calculated the theoretical nitrogen levels that can be expected based on fertilizer nitrogen applied. These values are a good starting point when estimating losses that may have occurred prior to the nitrate and ammonium soil sampling date and can be used to fine-tune side-dress target rates.
https://www.agry.purdue.edu/ext/corn/news/timeless/AssessAvailableN.html
Monday morning quarterbacks can usually do an admirable job determining the ideal nitrogen rate for last year’s corn crop but estimating nitrogen losses, soil nitrogen mineralization, and dialing in the perfect nitrogen rates for the current crop has many challenges. Soil nitrate and ammonium testing can be a useful tool to aid in these decisions.
Social distancing is a foreign concept to many in sales. Like most salespeople, I am used to shaking hands, and hopefully being warmly greeted when walking into an office or place of business. I find this lack of direct personal interaction odd and unfamiliar.
While I cannot visit a customer in person, I find myself thinking from time to time about the mechanics of an in-person sales visit. While it may be more intuitive to some, all successful salespeople observe the environment around a direct personal interaction with a client or fellow industry member. We notice pictures of family, objects that may indicate personal interests or logos that show brand allegiance. Sometimes, even the smaller details have a story to tell. I took a break from the doldrums of the computer today and noticed wear marks on my computer mouse where the entire outer surface of the left mouse button is worn away. Even a worn mouse button has meaning; a story to share.
Here at ALGL, our sales staff is also the agronomy staff. While this group of individuals has a very diverse range of experience and knowledge to support the customer in the use of our data, this staff is also a key part of our data quality. We aim not to turn soil analysis results the next day; the day after the soil is analyzed at ALGL the data is in the hands of our quality control department for a final review, and then in the hands of the agronomy staff for a second review. The agronomy staff is looking at the final reported data from an application perspective.
Those wear marks came from this member of the agronomy staff clicking through 100’s of reports a day. Like the rest of the agronomy staff, I am trying my best to ensure the data meets the expectations of our customers that I have the honor of getting to know personally when I fulfill the dual role of agronomist and salesperson.
Written by agronomist Jamie Bultemeier
Over the last few years many growers and crop advisors have concluded that they must supply sulfur for their crops to thrive. However, there remains confusion about which product to use, when to apply, and how much to use. The good news is that there are numerous products available that are affordable, but it is critical to pick the right product, or products, to best fit a grower’s application options.
Sulfur fertilizers deliver sulfur in three different forms, sulfate (SO4-), thiosulfate (S2O32-), or elemental sulfur (S8). However, plants can only take up and utilize sulfur in the sulfate form. Applying sulfate containing fertilizers, such as ammonium sulfate, means that the sulfur is plant available as soon as the product dissolves. Fertilizers containing thiosulfate require an additional step to become plant available. The conversion of thiosulfate to sulfate is an oxidation reaction that is both chemical and biological. The portion that is converted chemically will become available relatively quickly with little influence from soil temperature. The rate of availability from the portion that is converted biologically is highly dependent on soil temperature, moisture, and pH. However, in normal growing conditions, most of the sulfur applied as thiosulfate will be available within a couple weeks. Sulfur supplied in an elemental form must go through a biological conversion to become sulfate. The rate that this process occurs is entirely weather dependent. However, it is generally estimated that about half of the elemental sulfur will become available during the growing season.
The timing of fertilizer applications in the Eastern Corn Belt is generally confined to post-harvest, pre-planting, or early in-season. Since much of the phosphorus, potassium, and liming materials are applied post-harvest, this provides an opportunity to blend a dry sulfur product with these, but which one? In most cases, sulfate forms should be avoided in the fall. While it may be convenient to blend ammonium sulfate or potassium sulfate with another dry fertilizer, these are the most prone to being lost before the next growing season. Most sulfate containing fertilizers are highly water soluble and sulfate is highly leachable from the soil profile. The exception to this is gypsum, which is calcium sulfate. While it is a sulfate form, it is not as soluble as most other forms. For the greatest efficiency of fall applied sulfur, elemental sulfur should be used. The cold, wet soil conditions over the winter months are not conducive for the biological conversion to sulfate to occur. For pre-plant and early in-season applications, sulfate and thiosulfate forms are a good option to ensure availability to the growing crop. In a dry fertilizer pre-planting application, blending ammonium sulfate with urea is a good option. At planting, a small amount can be applied as ammonium thiosulfate in a 2x2 starter, but this should be a minimal amount to avoid damaging the seed since ammonium thiosulfate has a high salt index. Ammonium thiosulfate can be applied at higher rates in a sidedress application in-season because higher salt concentration is farther from the actively growing roots. While elemental sulfur can be applied in the spring, it should be done in conjunction with a sulfate form to ensure early season availability.
Choosing the right rate of sulfur is also important to maximize the benefit of the application. A common practice is to apply a crop removal rate which is approximately 15 lb/acre in a 200 bushel corn crop or 70 bushel soybean crop. However, the total crop uptake is about double the crop removal rate. Soils do release a small amount of sulfur from organic matter decomposition, and a small amount is deposited from the atmosphere in rainfall, but in many cases, this is not enough to supply total crop uptake, even if a crop removal rate has been applied. On soils with low organic matter, well drained, or very low testing sulfur levels, application rates should be closer to a total crop uptake amount. On soils with higher organic matter, poorly drained, or medium to high soil tests, a crop removal rate should be sufficient.
Sulfur is a critical plant nutrient that should not be overlooked. Fertilizer inputs should be managed to ensure that it is provided to the crop when it is most needed and in a form that will be available to the growing crop.
A rock solid agronomic recommendation is a good place to start when making cropping plans. However, the benefits of a library of sound agronomic knowledge and thoughtful planning by your team of consultants will not be realized if the application misses the target. Many field operations are controlled behind the scenes by sophisticated software and electronic systems that perform most of the heavy lifting, and we rely on these pieces to work together to place valuable inputs in the correct place and in the prescribed amounts. It is easy to become complacent and believe the values displayed in the monitor accurately reflect the true performance of the system.
Trust but Verify. Before the equipment leaves the shop, take time to verify equipment settings and calibrations that feed information to the control systems. Measure the performace near the normal operating range and also check slightly below and above the range to check for potential problems. For example, a flow meter that will normally be operating at 12 gallon per acre might check out fine at 3 GPM or 25 GPM but miss the mark at 12 GPM where it counts.
List equipment by category and identify parts by serial number or a personalized identification system so that records can be kept on past calibrations, as this will help identify parts that may be failing and need replacement. Think through your operation and list the critical components that need to be performance checked on a regular or seasonal basis such as Scales, Load Cells, Flow Meters, Flow Control Devices, Metering Devices, Planter Seed Meters, Speed and Distance Sensors, Starter Fertilizer Systems, Guidance Systems, and Row Clutches.
An often overlooked component is the liquid meter supplied with a bulk pesticide shuttle. If these meters are not owned by the farm operation and provided by the retailer it can be a challenge to keep up with the maintenance and proper performance of the pump and meter but it is a critical part of the pesticide application. For example, pull records from last year and look at the total gallons used for a common liquid bulk product and calculate the financial impact if a bulk meter is over-applying by 12%. It takes only a few minutes to pump the product into a calibrated 5 gallon container to verify proper performance. Always calibrate using the specific product that will be metered as viscosity differences among products may cause errors in measurements. When measuring dry products with a volumetric container supplied by the manufacturer always use the container labeled for your specific product as changes in density among products can lead to measuring errors. It is advisable to check these measuring containers with a scale when possible.
If ground wheel metering systems are used it is important to check rates and calibration performance in field conditions where the machine will be operating. A rough set-up calibration can be made on a hard road or smooth grass area but actual field performance will change and adjustments need to be made. A permanently marked distance of 200 to 400 yards verified with a tape measure can be useful especially when equipment fails and new parts need to be calibrated quickly during the season.
Now is the time to verify calibrations that will be critical in getting your crop off to a great start.
The first signs of spring are beginning to show in the Great Lakes region. The sun and warm weather are causing the ag industry to stir. At the lab we have seen increased sample volumes indicating the beginning of the 2020 spring soil sampling season.
The fall 2019 soil sampling season began with the sampling of prevent plant acres in June of 2019 and continued into February of 2020! During the mild winter weather, the past few months some of the soil samples collected were of better quality than others. No matter the soil conditions, soil sample collection depth remains one of the leading causes of soil sampling error. Often when soil samples do not trend with historical results, depth is a factor. So how does this impact winter and early spring soil sampling?
When soil is above field capacity and reaching saturation, the soil physical properties change. The excess water acts as a lubricant allowing soil particles to slide past each other much easier. This can lead to a wide range of soil sampling challenges that can vary by soil texture. As a tube soil sample probe is pushed into the soil, the soil can simply move to the side, thus reducing the soil volume in the probe. If the relatively higher fertility surface soil is reduced in relative soil sample volume, the resulting reported soil nutrient values decrease the same as if the sample was taken to deep. If soil from deeper in the profile is displaced, the reported soil nutrient values will increase, the same as taking a sample too shallow. Auger probes are often more impacted by above field capacity soil moisture than tube probes. Auger probes can simply push the soil to the side rather than retain the soil in the sample. All of these situations are denoted by a lower than normal soil sample volume for the given number and depth of individual soil cores.
Soil samples that are collected when the surface of a nearly saturated soil is frozen often also leads to challenges. As a soil probe is pushed into the soil, the frozen surface soil an act as a plug and prevents soil from entering the probe. Soils can be sampled at moisture levels above field capacity, but extra observational care needs to be taken to ensure the proper depth and volume of soil is collected.
Another challenge we see at the lab is soil bag degradation when shipping of saturated soils. If the soil sample is not shipped quickly after sampling, shipping is delayed, samples are poorly packaged allowing for movement, or the boxes are handled roughly in shipment. The bags can rupture, bag labels can come off, gel and felt tip ink can run, and label information can be rubbed off leading to the loss of the sample or sample identification.
While we welcome the arrival of your soil samples at the lab, but we want the resulting data to be useful and make a positive impact in your soil fertility management. It all starts with a good sample. If you can collect a quality sample in these soil conditions, sample on! If not, stop. If it takes a few days of dry weather to get a good sample, not a problem, we will leave the ICP’s lit for you!
Manure applications can be a valuable component of a nutrient management program but timing those applications to maximize the utilization of nitrogen can be challenging. Manures generally contain two forms of nitrogen, ammonium and organically bound nitrogen. Ammonium is immediately plant available and relatively immobile in the soil because it is a positively charged ion that held by the cation exchange capacity, similar to potassium. Organically bound nitrogen is also immobile in the soil, but it is not plant available until the organic matter is microbially decomposed, mineralizing the nitrogen.
In an ideal situation, manure applications would occur either into an actively growing crop or shortly before a crop is planted to gain the most benefit from the nitrogen. Unfortunately, our cold wet soil conditions in the spring and the types of application equipment we have available often do not allow for spring or early summer application. As a result, much of the manure in our region is land applied following harvest in the fall and early winter leaving several months for potential nitrogen loss.
The first step to maximizing the benefits of manure is to keep it on the field and in the soil profile. The most obvious potential loss of nitrogen when manure is fall applied is surface runoff. Runoff can be minimized by avoiding applications on saturated, frozen, or snow-covered ground; incorporation with tillage; or subsurface injection.
Once the manure has been incorporated into the soil profile, there is still the potential for substantial nitrogen loss to occur before the next crop can utilize it. The two potential mechanisms for loss are leaching and denitrification. Leaching has the greatest potential to occur on well drained soils during periods of heavy precipitation. However, for significant losses of nitrogen to occur due to leaching, the nitrogen needs to have been converted to nitrate prior to the precipitation. The conversion of ammonium to nitrate is a microbial process that will only occur when the microbes have adequate temperature and aeration in the soil to be active. Denitrification is the conversion of nitrate to gaseous forms that can be lost to the atmosphere. This is a microbial process that only occurs when soils are saturated, and the microbes are in an anerobic environment. Microbial activity is minimal when soil temperatures are below 50 degrees. If soil temperatures remain cold after application, the chances of significant nitrogen loss are minimized.
The winters and springs in this region are generally cold enough to keep most of the nitrogen in the soil profile. However, over the last few years this has not always been the case. The spring of 2017 was unusually warm with February and March temperatures reaching 70+ degrees. In one situation, using a soil nitrate and ammonium test, we were able to confirm the loss of nearly all the nitrogen following a fall hog manure application that was subsurface injected and treated with a nitrogen stabilizer. The grower in this situation had to supply a full rate of nitrogen fertilizer though sidedress to sustain his corn crop. The next season, following the very cold spring of 2018, the same grower in the same exact situation was able to confirm that no additional nitrogen was needed to produce his crop.
Following a relatively mild winter, the approaching spring of 2020 looks to be warmer than average leading to greater potential losses of nitrogen. If you are planning to plant corn into a fall manured field, a pre-sidedress soil nitrate test is the best tool to assure that you have adequate nitrogen. For more information regarding sampling procedure and data interpretation, please see our fact sheet.Over the past few months, many winter meetings in Indiana, Ohio, and Michigan have included presentations that previewed some of the possible changes in the Tri-State university fertilizer recommendations. One of the more publicized changes is the change in the chemical solutions used to extract soil nutrients in the laboratory from Bray to Mehlich III for phosphorus and from ammonium acetate to Mehlich III for potassium. While change can be challenging and concerning, this one is easy.
A&L Great Lakes Laboratories, like most leading soil labs, has been using Mehlich III as a universal extractant since the 1990s. Mehlich III is a slightly stronger acid and results in soil test values that are 10-20% higher depending on the nutrient. However, in order to facilitate interpretive guidelines, such as the current Tri-State soil fertility recommendations, which require Bray P1 and ammonium acetate K values, we employ a calculation to convert the Mehlich III value to a Bray P or ammonium acetate K equivalent.
Updated Tri-State fertilizer recommendations will reflect the use of the Mehlich III extractant, and will base recommendation calculations on the M3 values rather than the Bray P1 and ammonium acetate K values. During this transition period, it will be important to ensure that the soil extractant indicated in soil test data matches the fertilizer recommendation chart or equation being employed. With soil samples collected every 2 to 4 years, there will be a transition period were both data values may be part of this process.
Here at A&L Great Lakes Laboratories, we offer a wide range of reporting options to meet various customer’s needs. We will not be changing any soil test report formats to Mehlich III data until it has been requested by the customer. If you have any questions or need assistance once these university recommendations are released, please contact your ALGL agronomist or call the lab directly at 260-483-4759.
Have you enjoyed our customer photography calendars over the past three years? Do You have photos to share? We are excited to announce that we are launching our fourth year of the customer photo calendar and the participation continues to grow each year. We want to see pictures that illustrate what fuels your passion for agriculture 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, 2020. In September 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 2021 calendar. Follow us on Facebook for voting details. Everyone that shares a picture will receive some ALGL merch!
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The 2019 Soil Test Data Summaries for the Great Lakes region are now available on our website. The summaries are compiled for the Great Lakes region as a whole, as well as broken down by state and into geographic quadrants within each state.
The Soil Test Summaries are valuable tools that provide the average soil test levels for a given region, as well as the distribution of soils by rating. This data can be used by growers and advisors alike to identify regions where soil test levels tend to be low or high for a given nutrient, and can allow them to better focus their soil sampling and nutrient management priorities.
A&L Great Lakes has been providing soil test summaries since 1996, and the information provided has been used by countless agricultural professionals ever since.
The end of the calendar year for many agronomists and producers is denoted by the beginning of the winter meeting season and the conclusion of the growing season. Visiting among fellow agronomists and producers this time of year, a common topic is the sharing observations and lessons learned from the past year, and the 2019 growing season provided a lot of material for these conversations! Many are ready to put the challenges of 2019 behind and look forward to the 2020 growing season. While the delayed and wet spring planting of 2019 set the stage for many of the management challenges we faced during the 2019 growing season, the fall harvest of 2019 and the resulting management decisions have added to the legacy of 2019 that will impact producers for the coming years.
Years is correct, this is not a typo. So, from a soil perspective what will be some of the challenges moving forward?
First topic up for discussion, shallow compaction. Many fields during the wet spring of 2019 were tilled too wet during seed bed preparation. The conditions in much of the region were wet enough that any seed bed preparation, regardless of tillage tool used, created a shallow tillage layer. If these acres were harvested early and primary tillage was completed before the fall rain set in, this was alleviated to some degree. In many cases the quality of the soil structure was degraded, and a fall tillage pass will not completely correct this.
Correcting tillage layers by allowing the soil structure to improve will take time and less tillage, not more. There is a chance of the 2019 tillage layers impacting the rooting of the 2020 crop. Be watchful for tillage layers when scouting in 2020 by evaluating plant roots to identify fields that may be candidates to receive additional corrective actions like cover crops. If possible, limit the number of tillage passes in the spring of 2020 as to limit the potential for maintaining or making this issue worse. If 2020 proves to be another wet spring, always remember doing no tillage is an option in some cases. A tillage layer can be created any time soil is lifted, shifted or moved.
Deep compaction will also be an issue. Many fields were harvested wet in the fall of 2018 leading to deep compaction. Much of this land did not see quality primary tillage in the fall of 2018 or in the spring of 2019, and wet soil conditions later in the fall of 2019 may also hindered correction of these issues. Much of the early harvested 2019 crop was done in dry soil conditions that keep the issue from getting worse. Many acres received primary tillage under these favorable conditions. However, there was a considerable amount of primary tillage that was completed later in the fall after the fall rains began. This tillage may have removed the surface ruts and overall improved the appearance of the soil surface, but the deep compaction may still remain.
In 2020, place a focus on placing earlier maturing hybrids/varieties in those fields that were primarily tilled this fall in wet or less than ideal conditions. Focus on an early harvest of those fields with the greatest risk of deep compaction remaining from 2018 or 2019. This will increase the opportunity to complete the 2020 fall tillage in the best possible conditions.
The wet fall of 2018 prevented the collection of some soil samples, they were delayed until the spring of 2019. Some of these samples were not collected due to the wet spring of 2019 and then were delayed till the fall of 2019. Some of those remain uncollected yet in the fall of 2019. Some producers took the opportunity to perform fall primary tillage immediately after harvest rather than wait for soil sampling or fertilizer application. Collecting soil samples after fall tillage is not wise. So, what are the options for soil sampling?
First off don’t make matters worse, any variances in the soil sample collection process can impact or vary soil test results. Repeatable and trackable soil test results over time require as much constancy among sampling events as possible. The following are ranked in the order of potential impact on sampling variation in soil test data.
If your soil sampling is out of normal sampling sequence here are some fertility management ideas to consider
The fall of 2019 again forced some producers to make decisions that they did not wanted to make. Delayed planting lead to delayed crop maturity, leading to wetter harvest moisture, leading to slowed or delayed harvest, leading to … and the list goes on. There were consequences to the action taken or the inaction of many decisions this past year. In most cases it was not about making the “right” decision, but rather the least wrong decision. The decision that has the least costly long-term impact for the operation. Many of us may not want to accept the decisions we made managing the 2019 crop, but always remember you made the best decision you could with the information a you had at the time. Many times, there was no “right” answer in 2019.
"A&L Great Lakes has been an excellent company to work with since we started using them as our soil testing lab in 2017. Their staff is always knowledgeable and happy to assist in any way they can. Their soil testing is of the highest standards and extremely accurate, dependable, and timely. I have worked with many different soil testing labs and I can hands down say that A&L is the best in the business and we look forward to working with them for many years to come."
Ryan Powell
Ag Info Tech, LLC
A&L Great Lakes Laboratories, Inc. is an independently owned and operated agricultural testing laboratory located in Fort Wayne, Indiana. Our intent is to deliver fast, accurate analyses that you can trust to make your most important decisions.
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