News

Adoption of Mehlich 3 Soil Test Data

ALGL has need utilizing the Mehlich 3 (M3) universal soil extractant since 1991, however most of the data sent to customer over the past 30 years has been regressed and reported as Bray P-1, ammonium acetate, hydrochloric acid, and how water boron equivalents. This has been due to most interpretive fertilizer application recommendation sets have historically been in these traditional extractions. These traditional lab methods are commonly referred to as “North Central Region” (NCR) methods. With the revision of university-based fertilizer recommendations in Indiana, Ohio, and Michigan we are seeing an increase in customers opting to receive soil test data in the raw M3 values.

Below are some suggestions to help make the transition to M3 easier.

• Make the conversion at a transitional time of the year, not in the middle of a fertility decision cycle. For example if you collect soil samples in the spring, make recommendations and review with producers in the summer and apply in the fall. A good time to make a clean transition to M3 would be in the winter prior to the collection of spring soil samples.
• Don’t convert a field in the middle of a sampling cycle. If you sample every 4 years, wait until the next sampling cycle to convert a field. While it may seem best to change all fields at one time, changing within a sampling cycle can create more confusion. A clear transition time (month and year) is useful to verify what method a given field’s data is in by comparing the sample collection date to the M3 transition date.
• Share a mailer or meeting with growers as to when the change is made and how M3 data compared to past NCR data. Your ALGL agronomist has education materials that can be used to help in this process.
• Make sure to have fertility equations for both data types in your GIS software. Be sure to develop a process to ensure the correct equation is applied to the correct data, a clear transition date as mentioned above can help with this.
• Be sure to communicate with your GIS software provider, most software need to identify if the data is M3 before the data is imported. Our software company can walk you through the needed changes.
• Contact the lab before the transition is to take place. ALGL will need to adjust your account and possibly the GIS data export process to ensure that your data flow is not interrupted.
• While it may seem best to report both data values for a period of time, or to convert past data, this has proven problematic. It is best to make a defined transition at a preset and strategic time. For one sampling cycle there will be two forms of data active, the key to managing this period of data is to be able to clearly identity the method reflected in the data.

ALGL will only change data export form upon request by the customer. If you have any questions in regard to changing to M3 data, or if we can be of assistance in the transition, please reach out to your ALGL regional agronomist.

Why is the Buffer pH Blank on My Soil Test Report?

A common question get at the lab is, “Why is the buffer pH on my soil test report blank?” When the soil pH is 6.8 or higher, the buffer pH will be blank on your ALGL soil test report, and for good reason. The reason stems from what the buffer pH value is used for.

On a ALGL soil test there are two pH columns, one titled “Soil pH” and one tilted “Buffer pH”. The soil pH is measured by combining equal parts soil and water to create a slurry. Then the pH of the slurry is measured with a pH meter. This value is used to make management decisions and indicates how the soil chemistry will be affected. For example, this is the value used when referring to soil pH restrictions on pesticides and is the pH value that is managed in soil fertility. If the soil pH is below the desired level, usually 0.2 - 0.3, the buffer pH is used to determine the amount of lime to apply to correct low soil pH soils. In high organic matter soils and soils with a CEC of 7.0 or less, other methods to determine lime application rates are used.

The highest desirable soil pH is 6.8. If a soil has a pH is 6.8 or higher there no need for a lime application to increase soil pH and therefore there is no need to determine a lime rate. Thus, no need for a buffer pH value to determine a lime rate. In GIS software data sets a value of 7.2 is often used to ensure the software calculates a “zero” lime rate without causing an error due to missing data.

2022 in Review

The 2022 growing season could be summed up as variable. Throughout the growing season areas experienced too much rain, too little rain, and both. Leading to wide variety of water stress induced nutrient deficiencies in the crop. Despite the moisture stress the yields we good, and harvest was expedient.

Many producers pulled back on fertilizer application rates in the fall of 2021. That same trend continued into the fall of 2022 as the fertilizer prices, while variable, were showing no significant signs of relief. The question continues to be, “how long can growers go with reduced fertilizer applications?” While all fertilizer decisions are dependent on the parameters of a given situation, those growers that have focused on maintaining soil fertility levels over the past few years have had, and still have a distinct advantage.

Since nitrogen is an annual replenishment to the cropping systems, the focus of this question has been on phosphorus and potassium. It takes considerably more fertilizer to increase or decrease phosphorus soil test levels, then potassium soil test levels. Also, in most situations, crops remove less phosphorus than potassium. It may take several years of significant reductions or omission of phosphorus to start showing up in soil tests, but at some point, it will. Potassium soil test levels can decline quickly, 1 or 2 years of omitting potassium fertilizer can result in decreases in soil test levels. Potassium also impacts a plants ability to handle water stress, too much or too little.

The current market indicators are showing an increase in supply and a decrease in demand for phosphorus and potassium going into the 2023 growing season, this indicates a downward pressure on P and K prices. If this carries out, we will see 2-3 years of declined fertilizer application rates. This will be good timing for phosphorus but could be stretching potassium a bit.

The positive in all of the product challenges is that shortages were minimal. With alternates products available in most case this was a good opportunity for producers to grow in their management. This has led producer to try new products and new practices in their operations. Over the past year the agronomy staff has had a significant increase in conversations with client about closer management of nutrients, especially nitrogen. The positive to the higher prices is an overall tighter management of nutrient applications. In 1888, German philosopher Friedrich Nietzsche first stated, “Out of life's school of war—what doesn't kill me, makes me stronger.” This phrase has wide applications as the 2022 growing season pushed many producers, but it also made them better managers.

2022 also pushed us as a laboratory. We were ordering supplies upwards of 6 months in advance to keep the lab operational. The entire year was plagued with supply price increases, supply shortages, shipping delays and labor shortages.  The spring soil sampling season volumes were higher than normal with many samples not completed due to the wet fall of 2021, which prevented some soil samples from being collected. This along with strong fertilizer prices led to increased soil sample volumes in the spring of 2022. Strong grain prices supported stronger than normal plant tissue testing volumes during the summer. The fall soil sampling brought a compressed sampling season. Southern Indiana through Tennessee was 3-4 weeks behind in crop development while Michigan and Wisconsin were 2-3 weeks earlier than normal. Usually, samples start coming in from the southern parts of our sales territory in mid-September and there is a 5-7 week delay until northern Michigan hits full harvest. This year the entire service territory started in early October, compressing that start window to about 2-3 weeks.  Without any major weather systems hitting the region, sample volumes were continuously strong from early October till early December.

While 2022 proved challenging for all aspects of crop fertility in production agriculture, the dedication of those we work with made it successful. Thank you to our suppliers for doing what they could to always keep us operational. Thank you to the lab staff for their creativity, planning and amazing work ethic to do whatever it took to keep the samples moving for our customers. Finally thank you to our customer for putting your confidence in us, for the long/constant hours to keep the samples flowing into the lab, and for the partnership to work through any challenges that arose. While 2022 was difficult, it was also rewarding to see what we all accomplished working together.

2022-2023 Winter Fertilizer Price Outlook

Through the last quarter of 2022, prices of nitrogen, phosphorus and potassium fertilizers continue to diverge. As the price of these fertilizers increased at different rates, and for different reasons starting back in early 2020, the prices continue to respond independently. As phosphorus prices began climbing slowly in 2020, potassium followed later in the winter of 2020/2021.

In agricultural production, the adage “hindsight is 20/20” is all too true in respect to fertilizer purchase decisions the last two years. For example, as prices climbed in 2021, those producers that purchased the elevated prices in the summer of for application in the fall of 2021 made a wise decision as the prices continued to climb through harvest and the following growing season. Delayed fertilizer purchases, and application, has led to increased input costs during the 2021 and 2022 growing seasons. Looking back hesitation has not been a profitable approach to fertilizer purchases, which is often the case in any strong fertilizer price rally. Conversely, those that hesitate may benefit as prices decline.

So, what does the future hold? Foreseeing the future is an educated guess at best. Fertilizer prices are beginning to soften due to reduced demand backed with ample production. The exact opposite market forces that started the climb in prices in the fall of 2020.

How far and how soon fertilizer prices decrease is not yet known, but the signs in the market are showing both phosphorus and potash to be trading sideways to down. The downward pressure is focused on potash, yet phosphorus is responding more. The outside market pressures driving the nitrogen market much more volatile currently. It appears for the near future that nitrogen will remain choppy at best. Of the three main nutrients, nitrogen is impacted the most by the outside markets with continued steady to growing demand in the coming months.  

The Chemistry of Fall Colors

Sometimes we as agronomic professionals become a bit anesthetized to the amazing and complex natural systems that we work with every day. The myriad of intricate chemical, physical, and biological interactions that make our soils function to support plant growth, clean our water, recycle nutrients, and overall sustain life on this precious planet are awe inspiring. And the plant, that "simple" form of life that has existed in different forms over millions of years, and that we as professionals have harnessed to feed  the world, is a delicate and complex machine, capable of utilizing light from the sun and elements in our atmosphere and the soil to feed almost every other form of life on the planet.

While most of the time these lowly systems work without much pomp or fanfare, every fall they put on a show for all of us to enjoy.

The tourism industry is gearing up for 6-8 weeks of high traffic, full restaurants and hotels and increased incomes as travelers head to their favorite locations to view the fall colors. As days become shorter, temperatures become cooler the chemistry of the changing tree leaves begin to reveal the spectacular fall scenery.  The National Park Service fall foliage map published September 21, 2020 show areas across northern MN, WI and MI at or near peak fall color and the prime viewing will move southward over the coming weeks.

Arborists have discovered some of the key environmental conditions needed to bring out the best colors are adequate summer rainfall with good growing conditions followed by a dry fall with cool nights, warm daytime temperatures and good sunlight.

Chlorophyll (green), carotenoids (orange), flavonoids (yellow), Anthocyanins (red/purple) and tannins (brown) are present in the leaves during the summer growing season but chlorophyll dominates the light spectrum absorbing reds, yellows and blues while reflecting the green color that we see.  Chlorophyll production slows during the early fall and anthocyanin production increases which allows the vibrant colors to come into view. In late fall tannin content increases giving many of the leaves a dark brown color and the bright reds and yellows slowly disappear.

These chemical processes involve many of the same components that we see in crop production, ornamentals and foods. Anthocyanin is produced and stored in corn leaves early in the season when nights are cool and plant growth is slow and it reveals the same purple colors in corn leaves that are apparent in the trees during the fall. Carotenoids give carrots their orange color and the yellow flavonoids give egg yolks their bright color.  Many combinations and variations of these same chemical components make up the bright flowers and unusual leaf colors that we see in ornamental plants. Tannins that give leaves their brown colors are responsible for the signature flavor of a green persimmon and they give tea leaves a variety of flavors.

The staff at A&L Great Lakes Laboratories would like to wish you a safe a prosperous harvest season and we hope you take some time to enjoy the beautiful fall colors.

When Is Dry Too Dry?

The dry soil sampling conditions this fall has led to a variety of questions focusing on when clients should stop pulling soil samples. The soils need to be very dry for an extended period of time before the impacts to soil sample data become noticeable. The first indication is when you are unable to collect a soil sample to the proper depth, especially with a probe sampler. Often an auger sampler will do a better job in dry soils. Incorrect sampling can have a bigger impact on soil test results than the dry soil itself.

Source: USDA

A good way to make a determination on when to stop soil sampling based on drought conditions is to use the USDA drought monitor.  Drought maps can be found at https://droughtmonitor.unl.edu/. The actual impact of drought on soil sample data will vary based on cropping system, region of the county, soils, etc. The following is a simplistic reference to help determine when drought conditions may bias soil test results. D0 drought should have little to no impact on soil test results providing a proper soil sample can be collected. However, D0 drought can begin to make sampling some fields with a probe challenging. Late D1 and into D2 drought is when you may consider stop sampling. This is about the point in the drought continuum when sampling and drought bias on soil test results can become noticeable. D3 is a time sampling should cease.  If you have any questions reach out to your ALGL Regional Agronomist.

Late Season Plant Tissue Analysis

Collecting plant tissue samples throughout the entire growing season to monitor nutrient levels has become a common practice over the last few years. As most of the crops in our region are now well into later grain-fill stages, plant tissue test results need to be evaluated with a cautious eye.

As plants transition from vegetative growth stages to reproductive stages, the nutrient content of the plant leaves will change, most noticeably nitrogen and potassium. These nutrients are mobile in plants, so as the plant starts transitioning to grain-fill, they may be translocated from the leaf to the grain resulting in low tissue test ratings that may not necessarily indicate a yield-reducing nutrient deficiency.

Another common trend in plant tissue test nutrient levels is an increase in micronutrient concentrations as the plants approach physiological maturity. This is a result of carbohydrates and other carbon-based molecules being translocated from the leaf tissues to the grain effectively reducing the biomass of the leaf. The micronutrients (iron, manganese, zinc, and copper) are immobile in the plant tissue, so they remain in the leaf that has a lower mass and are now present at a higher concentration. The micronutrients may be rated as high or very high, however, this may not be an indicator of excessive fertility or potential toxicity.

While plant tissue testing can be a very effective tool for fine-tuning a fertility program, be careful not to make drastic decisions based on late-season plant tissue test results alone.

Fertilizer Reference Samples

For fertilizer retailers and manufacturers, it is had been a best practice to retain a reference sample of all fertilizer deliveries. This practice can be very useful to producers that have on farm storage.  If an issue arises, a reference samples can be used to help identify causes and solutions. This is even more important today as we are sourcing fertilizer materials from new sources and at different times of the year. The reference samples area especially useful after the material has been applied and no more remains in storage. If you have any questions about fertilizer testing, please reach out to your ALGL regional agronomist.

Originally Published October 31, 2016

When fertilizer is applied to a field its nutrient analysis should match what is claimed on the fertilizer product label (ex. 28% nitrogen).  This means that the buyer gets what they want and pay for, and the supplier is paid for what they delivered.  This is almost always the case, but there are situations where there is a discrepancy.

When a fertilizer is offered for sale at any point in the supply chain (manufacturer, distributor, wholesaler or retailer) the seller and buyer need to be confident of the fertilizer analysis.  Samples are often collected and either immediately analyzed or retained in case a question arises.

We recommend each incoming load of fertilizer be sampled.  If the material is different from previous shipments (ex. color) it should be communicated to the supplier and a sample immediately sent for analysis.  Retain samples of normal-appearing materials in case a future question arises.  The length of sample retention is unique to each situation, but likely should be at least until the current crop is harvested.

Collection of fertilizer samples can be challenging, especially with bulk deliveries.  The state’s fertilizer inspector can provide procedures for sampling of various fertilizers:  liquid, granular, bulk, bagged, etc.  When your facility is being inspected it is a good practice to ask the inspector to provide you with a sample collected at the same time as the one they will have analyzed.  Should their sample show the fertilizer does not match the label the retained sample can be analyzed to independently confirm the analysis.

Retained fertilizer samples should be stored in air-tight containers to prevent moisture entry and spills.  Small 4–8 ounce plastic bottles work well for liquid fertilizers.  Solid fertilizers can be stored in zip-lock bags – compress the bag to remove air and then place in another bag.  Keep retained samples in a controlled temperature area.

Soil Testing In a Drought

Some locations in our trade area have experienced drought conditions and many of these areas continue to remain drier than normal.  If you are faced with sampling under drought conditions, the following information may assist you in your planning and the interpretation of the results that you receive.

Soil pH: Water pH readings may be 0.1 to 0.6 pH units lower than expected. This is due to a slight increase in soluble salts in the soil solution that haven’t leached into the soil profile. This condition does not alter the buffer pH result so the amount of lime recommended for most samples will not be affected. An exception to this would be sandy soils where the water pH determines the lime recommendation. However, sandy soils are leached more easily so the amount of soluble salts in solution may be much lower than a heavier soil.

Potassium: Soil test levels for potassium may be lower than normal. When soils remain extremely dry for extended periods of time, the moisture that normally keeps the clay latticework open for potassium exchange retracts, capturing the available potassium from solution. This will show up as a reduction in the soil test level. Also, potassium is easily leached from crop residue following harvest. With little rainfall, this potassium reserve could remain in the tissue. One caveat of this, though, is with inadequate moisture to produce normal yields, less potassium may be removed from the soil reserve.

Phosphorus: Soil test levels for phosphorus may be slightly lower than normal. The effect of the dry soil on phosphorus levels isn’t as dramatic as potassium, but less moisture in the soil may lower the soil test results. The same situation of reduced crop yields may result in less phosphorus being removed from the soil.

 Soil sampling technique: It is extremely difficult to sample dry soils. Often the top one or two inches of the core are compressed enough that some of this material may spill out of the probe. In minimum tillage situations, this could have a dramatic effect on the soil test readings. Also obtaining the correct depth of soil sample maybe difficult, auger soil probes tend to work better in extremely dry conditions.

Many of the areas that were suffering under dry conditions earlier in the season may have had enough time to equilibrate moisture levels prior to fall sampling so that some of the drought effects will be negligible. Reduced yields, though, will still be a remnant of decreased nutrients being removed from the soil. This year is one where soil sampling should occur to assess the effects of this unusual growing season.

Soil Sampling Season Preparation

The fall soil sampling season is upon us. Are you ready? Here are a couple of things you can do in advance of the sampling season to help things run smoother.

1. Call the lab, or your ALGL regional agronomist, to update your account if there have been changes in staff, email contacts, or phone numbers.
2. If you have made a change in software, call your ALGL regional agronomist so that they can modify your account settings to ensure that the data flow is correctly configured. It is also a good idea to do a test with a small sample number to ensure the data flows correctly and any needed changes in procedure are identified before the season starts.
3. Order soil bags and shipping boxes ahead of time. We are working hard to ensure that we have ample supply of sampling materials, but shipping delays could impact your access to supplies.
4. Check your UPS shipping labels, do you need more or have they expired. The expiration date is on the lower portion of your UPS labels, after this date the tracking of the package can become unreliable. If you need new labels call the lab or your ALGL regional agronomist and they can get new labels on the way.
5. Many customers are making the switch to Mehlich 3 soils data. If you have made the decision to switch or would like to make any changes to your reported data, contact your ALGL regional agronomist. The change to Mehlich 3 data can be made to your pdf reports, your data export files, or both.
6. Every January a summary of the previous year’s samples is posted to your eDocs account. That report shows what field by grower/farm/field that were sampled each year. For example, if you sample every two years, you can look back to the 2020 sampling report to ensure no resampling is missed.
7. If you are resampling for customers, take the time now to pre label the soil bags and pre generate labs submission forms.

Your ALGL agronomist representative is available to discuss you soil sampling protocols and help find way to streamline your fall soil sampling.