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The Good, the Bad and the Ugly of Wood Ash

In tight times it is common for growers to look to waste products as a source of nutrients. The products are also commonly marketed to growers.

Wood ash is often promoted primarily as a source of carbon and potash. It is often a good source of potassium, calcium, and carbon with a notable amount of phosphorus. The calcium is often calcium oxide which is powerful liming agent. The liming properties of wood ash are usually where problems can arise if not managed correctly.

While wood ash is a good source of carbon, it comes with a high C:N ratio. The more hardwood burnt to create the ash, the higher the carbon content. C:N ratios over 30:1 can become a nitrogen sink as microbes process the material. This can lead to nitrogen deficiencies in crops if not managed properly.

One ton of wood ash can have the same neutralizing capability of ½ ton of calcium or magnesium carbonate based ag lime. The concern arises when repeated applications of wood ash are made to meet a potassium nutrient recommendation without consideration for the liming potential of the material. Especially on high pH soils.

Excessive applications of calcium or magnesium carbonate based ag lime will result in a soil pH of 8.1 to 8.2. These soil pH levels can lead to a variety of challenges. The acid neutralization reactions of carbonate products stall at this pH. Unreacted carbonates will remain in the soil to neutralize any acid additions that maybe made to the soil. When soil reaches this point, it is very difficult to impossible to lower the soil pH. This is the main reason excessive lime applications are discouraged. Oxides, like those found in wood ash, can elevate soil pH into the low 9’s before stalling.

Whenever applying word ash, test the Calcium Carbonate Equivalent (CCE) of the material to compare to calcium or magnesium carbonate based ag lime application rates, avoid excessive or repeated applications, and monitor soil pH closely after application. If you have any questions about wood ash or other byproducts reach out to your regional ALGL agronomist.

Phosphorus Rate Reductions and World Demand Growth

Management of high phosphorus fertilizer prices has been common topic in the fall of 2024 and 2025. The elevated phosphate prices began in 2021, the depressed grain markets in 2024 and 2025 that drove the widespread cost cutting. A common approach has been to cut rates. More information on how to effectively reduce applications rates while limiting negative impacts can be found in a previous ALGL blog post “The Seven Most Expensive Words in Agriculture – Fertilizer Prices”.

Many rate reduction strategies implemented in the past two falls have been under the assumption that the elevated phosphorus prices will relax relatively quickly. Most fertilizer price spikes do not last very long and impact roughly two growing seasons. If this assumption is part of your phosphorus plan, a modification of the plan may be in order.

The drivers of this phosphate price elevation are a bit different than past price events that usually are a result of short-term supply interruptions or seasonal demand spikes. World demand for MAP is growing significantly as South American and Asia are looking to increase domestic grain production which has led to a significant/large increase in world phosphate demand over the past 4 years. The Asian demand increase has been driven primarily by China. China has significantly reduced phosphate exports to focus on domestic demand, thus lowering the world phosphate supply. It is foretasted that world demand should level off in 2026 with no indications of decline.

There are new sources coming online, however market forecasts are starting to project that it will be 2028 or 2029 before the demand and supply can align allowing phosphate prices to relax.

While many of us initially assumed that the high phosphate prices would necessitate reduced application volumes for 1-2 growing season based on application timing, high phosphate prices may be reality though the 2028/2029 growing season. Can your current plan support significant phosphate reduction until 2028 or 2029 without negative future impacts?

The base defense against negative impacts of altering your fertility management is routine and consistent soil sampling to monitor soil fertility changes along with tissue testing to monitor crop access to fertility. Reach out to your ALGL Regional Agronomist for help with soil fertility questions.

Potassium Fertilizer and Nitrogen Use Efficiency

When managing soil nutrient sufficiency ranges, most are attempting to keep each nutrient above the critical and within the adequate range.  This, of course, depends on the soil, region, crops being grown etc.  Sufficiency ranges have been developed over time through field calibration research, linking crop yield/response to soil test levels.  From these crop responses, different soil test ranges have been made insufficient, sufficient or excessive.  This has been the standard to determine a crop’s overall needs, but what has been studied further is the relationships between different nutrients.

There are many cause and effect relationships between soil nutrients.  Too much calcium, for example, can affect the phosphorus availability in certain soils.  Soil pH is the determining factor for nutrient availability etc.  A connection between potassium and nitrogen is not often discussed, and perhaps because there is present-day data supporting this.  Unlike calcium and phosphorus availability, potassium and nitrogen are more about aiding uptake.

Potassium (K) improves nitrogen use efficiency in a few ways.  The first is potassium contributes to root elongation.  Better root growth promotes contact with nitrates and ammonium in the soil for plant uptake.  Nitrogen is primarily brought into the plant through a process called mass flow.  Mass flow is regulated by plant transpiration. This is the movement of dissolved nutrients.  As the plant transpires, more soil solution is being brought into the plant through the root system.  Transpiration can have a large effect on nutrient uptake.  It requires soil moisture to regulate plant temperature, and water/nutrient transport.  Temperature, humidity, light and wind all play a part in the rate of transpiration.

Potassium is the primary ion controlling transpiration and plant nitrogen mobility.  Low K can cause nitrogen to accumulate in older tissues instead of moving to newer growth.  It controls the stomata movement on the leaf surface.  Stomata are the pores regulating water and gas exchange.  When stomata open, potassium ions move into the guard cells and vice versa when they close.  Without proper plant K levels, which can be greatly affected by soil moisture and clay type, the mass flow of nutrients such as nitrogen are inhibited. 

The fact is that growing organisms have a balance amongst themselves.  Yes, insufficient nutrient content can raise a plant but keeping them in a constant balance is what increases the efficiency of others for maximum yield potential.  Constantly maintaining a sufficient range of nutrients is the first step and the next is to learn the cause and effect of nutrient levels. 

Continued Challenges and Solutions in 2025

Editorial by Agronomist Jamie Bultemeier

Looking back on the past few years, a common trend is the challenges that arise within a growing season. One unique aspect to the challenges of 2025 has been that many of the challenges are continuations from 2024 while other challenges will linger beyond 2025.

Much of our service area was experiencing low level drought in 2024 that did not fully resolve through the winter leading into 2025. While rainfall may have been similar in 2025 as 2024, the lack of subsurface moisture added to the moisture stress in 2025. Dry weather can reduce nutrient loss and leaching. Dry weather also reduces nutrient uptake by plants. Low tissue test levels of potassium were a common sight at the lab though the summer months.

Our position on soil sampling in abnormally dry soil has been to first ensure that you are able to sample to correct depth. Incorrect sampling depth can bias data regardless of the chemistry impact of dry soil on lab methods. Dry soil normally leads to shallow samples with an increase in soil test data values. If correct depth can be achieved, chemical impact of the soil test results from the lab appear when a prolonged drought reaches the late D2 to early D3 status. There were indications of samples exhibiting significant soil pH and potassium level reductions in areas of extended D2 to D3 drought. Fortunately, this was again limited to a small portion of our service area again this year and the severity of the drought did not build until the later part of the fall soil sampling season.  One concern for 2026 will be the continuation of the drought. Near term precipitation forecasts indicate that drought conditions will persist in the coming winter.

The dry fall weather drove a near record harvest pace again this fall that tied 2024. Most sampling seasons have a weather event or multiple events that slows soil sampling in a significant portion of the ALGL service area. This reduces inbound soil sample volume overall and provides periods of time to catch up. There was no such event during the fall of 2024 or 2025. This in combination with record fall soil sample volumes led to increased inbound soil samples above our daily capacity without an opportunity to catch up. Our dedicated staff worked repeated Saturdays, which led to a record number of samples processed in one month, almost 10% more samples in a single month than the previous record.

2025 also marks the second year of high phosphorus fertilizer prices and elevated nitrogen prices. Many conversions between lab agronomists and clients have focused on effective ways to reduce phosphorus and nitrogen rates. Trends in the fertilizer supply indicate that nitrogen prices will remain elevated into 2026 and high phosphorus prices could endure until 2028. Some of the short-term reduction strategies for phosphorus may need to be rethought as it is likely that phosphorus prices to remain high longer than many have anticipated.

Soil Sampling Strip-Tillage Practices

Traditional soil sampling has a few common goals when the puller meets the field.  Consistency, uniformity and repeatable locations, all play a large role in good sample data.  How are these standards still applicable to a situation where fields are purposely not uniform and consistent?  By implementing strip-tillage practices, a microclimate is formed in the strip. 

Strip-tillage is a broad term.  Its classification comes from manually creating a banded tillage strip instead of other forms of disruption.  It could also indicate with or without fertilizer.  In a conventional tillage system, the whole area is worked as uniformly as possible.  This could be for multiple reasons such as residue, pesticide and fertilizer incorporation, seedbed preparation or the constant losing battle against compaction.

On some farms the goal changes from uniformity to concentration.  These same growers are generally wanting to band fertilizers, minimize erosion, and build organic matter.  By creating a concentrated strip on tillage and fertilizer placement, the residue is left between the rows.  This keeps the benefits of no-till and maximizes fertilizer placement.  One of the tougher challenges to strip-tillage is keeping soil sample data consistent.

Soil sampling the same spot/area after the same crop every time creates a trend for soil tests.  From here, an accurate recommendation can be made for the best return on grower’s investments.  Banding fertilizer is not the only alteration strip-tillage creates.  The tillage aspect itself will change the soil’s physical, chemical, biological and water infiltration properties compared to the soil not being disturbed between the rows. 

One way to sample strip-tillage acres is to increase sample core volume.  Traditionally, a field is sampled 15 cores per sampling location.  This is then mixed in a non-reactive bucket and placed in a soil sample bag to the fill line.  For strip-tillage, five soil cores are sampled perpendicular to the rows.  One slightly off center of each the right and then left rows, and three between the rows.  This is then mixed for one composite core.  As one could tell, this is very inefficient but necessary to have the best soil data.  There are many types of strip-tillage practices and each may need different sampling methods.  For tillage only, sample as normal.  If the bands are moved each year, take more cores in the sampling area.

One way to be more efficient, and possibly even more accurate, is to separate the rows and in-between the rows separately.  This will show what the nutrient levels are in each environment.  Certain nutrients must stratify, like the surface in no-till, and then move to the soil between the rows.  Either way, the same amount of nutrients must be applied as it was with a blanket spread.  With crop removal rates, it may not be too much at once, but for build recommendations, a split application of fall then spring will have to be used on some soils, regions, type of fertilizer and crop being planted.

Registration for 2026 Soil Fertility Workshops Is Open!

Dates and locations are set for the 2026 Soil Fertility Workshops. The goal of our workshops is simple: we provide a general overview of fundamental agronomic principles and current university research so our attendees are better able to make nutrient management decisions for their customers or for their own operations. Today’s producers are inundated with information regarding crop inputs and practices. By applying the fundamental principles of agronomy to these inputs and practices, a consultant, agricultural retailer, or producer can evaluate and decide which of those are most applicable for achieving both the short-term and long-term goals of a specific operation.

The workshops are developed and presented by A&L Great Lakes Laboratories’ Agronomy Staff comprised of Certified Crop Advisers, Certified Professional Agronomists, and Certified Professional Soil Scientists whom have a wide range of experience in the agricultural industry.

We will be presenting six workshops in January and February in Illinois, Indiana, Michigan, and Ohio. Registration can be completed online, or by mail/email. Click here for more information and registration.

February 4, 2026 - Fort Wayne, IN

February 11, 2026 - Rockford, IL 

February 12, 2026 - Valparaiso, IN   NEW LOCATION

February 18, 2026 - Frankenmuth, MI

February 19, 2026 -Perrysburg, OH

February 25, 2026 - Terra Haute, IN   NEW LOCATION

Making the Switch-Fall to Spring Soil Sampling

For most of the Midwest, drought conditions continue into the fall and winter months.  Field fires, low grain moisture, and tillage practices are proving to be difficult hurdles, but dry soil conditions make soil sampling especially difficult. Not only are soil sampling conditions challenged by dry soil, but lab results take more interpretations than seasons with adequate circumstances.

Fall soil sampling has, historically, been the peak timing for sending in numerous bags of soil to the lab.  This is due to many factors.  Once the grain is harvested, it leaves an open canvas to sample exactly where the client or sampler would like to.  This keeps the process as efficient as possible and leads to the most reliable data.  The lab reports the soil analysis for further review, and then the correct fertility program can be implemented. 

Testing when the crop is harvested not only allows for quicker/more precise sampling, but also applications can then be made without crop damage.  As most fertility programs apply in tons, or several hundreds of pounds, rather than small in-season amounts.  All this is possible because there seems to be more time at the end of the season to achieve applications.

Where this used to be the case, now many growers are hiring sampling and applications to be done.  Whereas before, growers needed that extra time in the fall to do it themselves.  Because of this, most research and response data has been for fall applied nutrients.  Now with new studies, technology and contracting sampling/applications there has been a movement to spring soil sampling. 

Spring offers many benefits to sampling compared to the traditional fall sampling.  There is more uniform moisture, and certain nutrients like potassium have been released from the previous crop residue.  It can be more ideal for a soil sample since dry conditions are not often experienced.  Growers may experience slightly higher pH values in the spring and potassium levels.  Nutrients like nitrogen and sulfur, anions, may leach and decline over winter months depending on precipitation, temperature and soil type.

Now that there are multiple windows of opportunity for sampling, some precautions must be taken into consideration.  If soil sampling and application are conducted the same season as seeding, it may delay some planting applications due to relying on samplers and applicators.  Depending on the product being applied, some salt injury could occur, or the nutrients will not be available in time for the new plants.  This in mind, many spring samples are for fall applications of fertilizer.  Especially if pH and maintenance programs are being utilized.

If you have any questions about how spring soil sampling may benefit your operation, please reach out to your ALGL agronomist. 

Fall Soil Nitrate Testing

Why is soil nitrate part of basic soil test packages at some labs and not at others? The answer is based on the primary geography serviced by the laboratory. While nitrate tests can be added to basic soil tests performed on fall collected soil samples, they may be of little value in some geographies.

Post season nitrate soil tests can be valuable in evaluating nitrogen management plans to determine if excess levels of nitrate remain after the crop is harvested. These results and interpretations are highly impacted by the weather.

In arid regions of the country that receive less then 12-14” of annual rainfall, the retention of meaningful nitrate from one season to the next is common. In regions that receive 20-30” of annual rainfall, very little if any nitrate is carried to the following growing season. This additional rainfall can leach soil nitrate below the root zone or cause soil saturation leading to denitrification.

Elevated rainfall is the reason that in the eastern corn belt crop nitrogen recommendations are not traditionally based nitrate tests unless there is manure applied within the cropping system. The conversion of organic nitrogen or ammonium nitrogen contained in the manure to nitrate can slow nitrate movement and loss that can have an impact on nitrogen application rates. To maximize the effectiveness of this concept in regions of elevated rainfall, soil samples for nitrate analysis should be collected shortly before additional nitrogen is applied in the growing season, not the fall before.

Secondly most nitrate test interpretations are based on a 0-12” or 12-24” soil sample, not the 0-6” or 0-8” samples traditionally collected for fall nutrient, organic matter, and soil pH. While there are versions of nitrate interpretations that convert shallower samples to a 0-12” equivalent, the conversion assumes that the soil concentration of nitrate is uniform through the sampling depth. This is likely not true in most situations. At ALGL we recommend collecting separate samples for nitrate tests to avoid the sample depth issue.

If you have any questions about adding soil nitrate analysis to your routine soil samples, reach out to you ALGL regional agronomist.

Evolution of Data Delivery

Just like the submission of soil samples has changed over the last 50 years, the way and format that the data is delivered back to the customer and end-user has changed quite drastically.

In the 70’s and 80’s laboratory results were transferred from handwritten sheets used for record keeping in the lab to hand-typed forms that were shipped back to the customer by mail. Any fertilizer recommendations were manually calculated. Little changed until the mid-90’s other than the incorporation of more efficient word processing computers and dot matrix printers.

The improvement in computer technology throughout the 90’s improved both data collection in the laboratory, reducing the potential for handwritten errors as well as the delivery of the data to the customer. The adoption of email not only reduced printing and postage costs but also reduced turnaround time. While printed copies are still available, email is highly recommended. If existing account holders are currently receiving hard copies that are not needed, please contact the lab to update your account preferences.

Since the early 2000’s, the development and adoption of precision ag/GIS software have driven the need for compatible electronic formats of the data. These could also be delivered by email.  The early software programs generally utilized spreadsheet type data formats such as csv’s. As the number of software programs continued to grow, so did the number of different data formats needed to accommodate each program. While this created some challenges for the laboratory. However, it encouraged software companies to have an open dialogue with laboratories so that their common customers could receive useful and timely data delivery.

The next steps in the evolution of datal delivery was the development of direct web exports to the software platforms. This eliminated the need for manual uploads of the data files, greatly reducing processing time for ag service providers. As more software companies adopted different forms of direct data delivery, once again the number of different formats required continued to grow. Also, the number of programs that a single customer used was growing. As a result, ALGL developed the ability to export up to 5 different data formats for a single sample or field of samples.

Over the last ten to fifteen years, the development of the MODUS format has greatly reduced the number of custom formats required for all the different software platforms. The goal of the MODUS format, which was developed in partnership with software companies and commercial laboratories, was to create a single unified format that any software company could use.

At ALGL, we have maintained the ability to deliver printed hard copies through the postal service all the way to 5 different electronic formats delivered at the click of a button. We will strive to accommodate whatever the future may bring, but for the current time we ask our customers to keep us up to date with any software changes or data format needs as they change.

How Does Improving Corn Nitrogen Use Efficiency Impact Corn Input Costs?

The nitrogen use efficiency or the amount of nitrogen in pound of N to produce one bushel of corn wide range in the. This can range from 1.4 lbs N/bu of corn to as low as 0.6 lbs N/bu of corn. This range is primarily defined by one of two things, N management and soil organic matter content.

Practices like fall N application without a stabilizer before soils cool to below 50° F on a course textured soil would rank at 1.4 pounds of nitrogen per bu corn or higher. As management actions are taken to improve nitrogen retention in the soil or increase crop uptake the nitrogen use efficiency factor can decrease. The more practices implemented the better nitrogen use efficiency factor can be realized. Practices include but not limited to side-dressing, late season nitrogen applications, fertigation, using nitrogen stabilizers, implementing rate plot and utilizing stalk nitrate tests to dial in overall nitrogen rates.

Each 1% of soil organic matter can release 20 to 40 pounds of nitrogen. The ultimate nitrogen release from soil organic matter is weather dependent, however a conservative portion can be taken into account towards total nitrogen rates. Click here to learn more about Effective Nitrogen Release (ENR).

So, what is the financial benefit to improving your nitrogen use efficiency? The higher the yield potential and the higher the nitrogen price the more it pays. All with the goal of maintaining yield. Improving nitrogen use efficiency 0.1 or 0.2 can have a notable impact on reducing input costs.