May 23, 2022

Intensive Pre-Sidedress Nitrogen Testing (PSNT)

Many acres of corn across our area are established with good stands and it is on its way into the summer growing season.  Soon it will be time to apply side-dress nitrogen and concentrate on the nutrient needs of the crop and prepare it for the rapid growth phase that is soon approaching.

Given the increased price of nitrogen and the strong crop prices that are available some of our customers are considering a more intensive pre-sidedress nitrogen testing program to help them better place their fertilizer dollars where it has the best chance of making the greatest impact on harvested yield.  Based on university data across the midwest it is strongly recommended that sample cores for PSNT be collected at a 12” depth to capture more of the mobile nitrogen as it begins to move downward through the soil profile.  For those interested in increasing the intensity of their sampling program it may be useful to collect PSNT samples on a 5-10 acre grid or zone pattern of 8-12 cores per sample.

It may be most useful to concentrate sampling efforts on fields with historically medium to high yield potential with good plant stands and fields with likely variable levels of nitrate availability such as areas that have had applications of manure, municipal waste and other organic forms of nitrogen.

It may be advantageous to adjust nitrogen application rates based on actual measured nitrate levels in the soil at side-dress time.  If you have questions or would like assistance with your pre-sidedress nitrate testing plan please contact your agronomist at A&L Great Lakes Laboratory and we would be happy to assist you.

May 17, 2022

Effects of Spring vs. Fall Sampling on Soil Test K

Potassium (K) soil test levels have the greatest potential to vary between fall and spring. Soil test K levels are usually lowest in the dry conditions of late summer prior to harvest and peak in the early spring. Potassium is released from crop residues as the crop matures and crop residues degrade, and this release continues through the winter months. In addition, potassium can be released from the soil through prolonged saturation and freeze/thaw cycles in the winter months. With these processes combined, the question becomes how much higher soil test potassium levels will be in spring- versus fall- collected samples.

A simple approach is to select a location in a field such as a grid or zone sample location and physically mark it with a flag.  Collect 6-8 cores at a depth of 6-8”. It is important to pull the same number of cores at the same depth each time samples are collected. Collect the cores as close as possible to each other and the flag. Do this in the fall and in the spring.

In most cases, spring and fall potassium levels are usually within 5-10%. Spring soil sampling does not always result in higher potassium soil test level; this depends on crop residue release and weather patterns. Below is an example of some actual field data collected in northeast Indiana in a clay loam soil with a corn/beans/wheat crop rotation with fertilizer applied after the spring sample collection. The key to proper soil sampling is consistency. Sample the at the same depth, following the same crop at the same time of year.


April 27, 2022

Calculating the Value of Wheat Straw

As producers work through the various budgets for the 2022 crop year there is one calculation coming up in a few weeks that shouldn’t be overlooked.  Wheat grain prices have been very strong recently, but if you are faced with the decision of whether to remove the straw or leave it in the field, take a few minutes to update the value of the nutrients that would be removed with the straw and make sure you are adequately compensated for the replacement costs.

The Ohio State University tells us that a well grown wheat crop will yield about 2.5 to 2.8 tons of straw.  Data shows that a ton of wheat straw contains about 11 lbs of nitrogen, 3 lbs of phosphorous and 20 lbs of potassium.  When we apply today’s fertilizer prices to the nutrients removed we can quickly approach $95.00/acre.

Compared to past fertilizer prices that placed the value of straw at around $17.00/ton the current value of the nutrients places the price closer to $35-40/ton.  Several factors can affect the actual removal rates such as rainfall following harvest and prior to bailing that will leach a portion of the potassium back to the soil.

If you would like to submit a straw sample to the lab for testing we can more accurately estimate the nutrients removed and assist you with your calculations.

April 19, 2022

Managing Expensive Nitrogen for Corn

With nitrogen prices hovering around $0.80 per unit, deciding when and how much to apply is becoming increasingly difficult. Below are some tips to help make the most of your nitrogen program.

Do not skip the starter. Research has shown the benefits of applying 20-30 pounds of N at planting. Starter should even be considered on manured fields. Cold soil temperatures early in the season prevent the mineralization of N from organic forms. A corn crop that starts behind due to lack of N is not likely to maximize yield at the end of the season.

Split applications of N into as many passes as feasible. The more frequently N is applied, the more efficiently it can be used. Explore late season options for application. A corn crop takes of 60-70% of its N requirement by tasseling. If 70% of the N is applied between starter and sidedress, any additional applications can be fine tuned based on the performance of the crop at that time.

Soil test for N (both nitrate and ammonium), even on non-manured fields. Using a PSNT to adjust sidedress rates is common practice but using soil tests later in the season to evaluate a nitrogen program is less common because there is no clear interpretation of the results. However, this data especially in the hands of a trained crop advisor, can be a useful piece of the puzzle that is N management.

Use tissue tests to help fine tune an appropriate late season application rate or possibly determine if the application is needed at all. Collecting tissue samples 2 to 4 times during early growing season can help to monitor how efficiently the crop is utilizing the N that has already applied. If N was applied at a rate assuming an average growing season and yield, but conditions are favorable for a higher yield, a tissue test can help determine if a higher rate of N is needed to produce that higher yield.

Most importantly chose an appropriate yield goal based on the history of the field. Applying additional N to a field that has other limitations such as drainage problems or low fertility will likely result in financial loss. Also remember that maximizing yield does not mean maximizing profitability. To help fine tune an appropriate N rate for your area and N prices, use the Maximum Return to Nitrogen calculator available at

April 11, 2022

The Value in Tissue Testing for P and K

When working with plant tissue data you can either react to the data with a nutrient application, or you can use the data to continue to develop your overall nutrient management strategy. Either way, routine monitoring of plant tissue test results is the starting point. While taking one tissue test at R2-R3 soybeans to identify a nutrient deficiency so that a foliar product can be added to the fungicide pass is common, it does not identify how long the deficiency endured. While on the other extreme, weekly tissue samples can be a pile of data to wade though. A good tissue testing monitoring program starts with a tissue test once the crop is well established, one or two while the crop is rapidly growing, one at the start of reproduction, and the final sample during pollination or grain fill.

When tracking tissue test results, weather and crop observation notes throughout the season, especially the week or two leading up to a sampling event, are critical. The main nutrient uptake routes for plants, diffusion and mass flow, require water. If water is limited in the root zone, short term nutrient deficiencies can appear until moisture improves. If the soil is saturated, nutrients that are taken up by mass flow will be diluted in the water and will have limited availability to the plants. 

Tissue testing provides an opportunity to identify and correct micronutrient deficiencies. If you can spray every week or two in a higher value crop, collecting tissue tests ahead of application will allow for management of low trending secondary and micronutrients. In commodity grains, weekly application of nutrients is not as practical, so being reactive to every change in a weekly collected tissue test is not practical. It is possible though with season long tissue testing to identify weak areas within the overall crop fertility plan and adjust the plan for future growing seasons.

For macronutrients like phosphorus and potassium, foliar applications in grain crops are often not enough to have a significant impact. The value to repeatedly collected tissue samples for management of phosphorus and potassium are the adjustments made to the timing and frequency of nutrient applications, target soil test levels, and rate of fertilizers in subsequent seasons. The goal for phosphorus and potassium to correct common issues that appear in tissue tests proactively in future years. To validate the effectiveness of the management changes, continue tissue testing after the implementation of the management changes.

March 17, 2022

Testing “Gray Area” Materials

Is it a soil? Is it a growing media? Is it a manure? Is it a compost? Is it a fertilizer?

Requests to analyze uncommon materials that cannot be completely classified as one of the above categories is becoming increasingly common. Some of these materials are industrial biproducts looking for a beneficial reuse. Some materials are novel products proposed to be used as “soil amendments”. Others are being evaluated to be a feedstock for composting or a component of a soilless or greenhouse media. To choose the correct testing methods, you need to be able answer a couple of questions about the material. What are your trying to learn about this product? How is this product intended to be used? Are there any regulatory testing requirements? If you can answer these questions, the following summarization of the different testing methods should help to select the appropriate analytical methods.

Soil testing methods for nutrients are done using different extracting solutions to estimate the fraction of the nutrients that are available or soon will be available for plant uptake to make fertilizer recommendations. These methods do not give any information about the total nutrient content and are generally intended to be used on soils that have not been heavily altered with other non-soil materials.

Growing media nutrient analysis is done through a process called a saturated media extraction. This process uses deionized water to extract the fraction of nutrients that a growing plant has immediate access to utilize. These methods are intended for materials with little or no natural soil in them and will be used to grow plants in directly.

Manure testing methods use a complete digestion to measure the total nutrient content of the material. Using the moisture content of the material, the nutrient levels can easily be converted into units of pounds per ton or pounds per 1000 gallons which is useful for calculating appropriate application rates. In addition to animal wastes, these methods can be utilized on many other materials that are being land applied for disposal.

Compost testing methods will produce very similar results to manure testing but are done using slightly different methods that are approved by the U.S. Composting Council. These methods are intended finished compost products that will be sold commercially. However, if a material is being evaluated as a potential feedstock for composting, it should also be analyzed using compost methods to allow for equal comparison to the final product.

Fertilizer testing utilizes many different methods depending on what nutrients or other components are requested. These methods are very accurate and intended to be used for products that require a Guaranteed Analysis for the sale of a product based on its nutrient content. Also, if a product is being tested as a potential liming material, it should be analyzed using fertilizer methods.

Please be aware that materials being tested as a beneficial reuse of a waste product, a liming material, or a fertilizer may fall under different state regulations and require additional testing such as heavy metals that are not included in ALGL’s routine test packages. If you have any questions regarding proper testing of a “gray area” material, contact your ALGL representative.

March 08, 2022

Soil Sampling in Advance

At ALGL we are seeing an increase in spring soil sampling. Spring soil samples have increased from 15% to 28% of annual soil samples in the past 10 years. Perceived concerns of seasonality impacting soil test data are being overshadowed by increased management flexibility.

Tradition has held soil samples to the fall sampling season. This works very well if the plan is to apply fertilizer in the spring, thus allowing time to make management plans over the winter months. More commonly the plan has been to collect the soil samples and turn the resulting data into fertilizer recommendations as fast as possible. This plan leaves no time to make key management decisions. The growing trend in our market is to separate soil sample collection, and fertilizer application, into separate seasons.

Soil test results will vary through the year. Often, nutrient levels are highest early in the crop growing season and decline through the growing season, with a recovery as nutrients begin leaving crop residues at harvest time. It is often argued that fall soil sampling shows the seasonally lowest soil test levels to ensure adequate crop fertility. A similar argument can be made for spring soil sampling in that it directly reflects what the starting point for crop fertility at the beginning of the growing season.

The greatest concern is with potassium soil test levels as it has the greatest chance of variability through the growing season. Demonstration samples collected over the last few years by ALGL shows that potassium levels vary less than ± 6-7% between spring and fall soil samples. This is often less than the cumulative sampling error between sampling events. The difference will have little to no impact in the resulting fertilizer application rates in most cases.  It is assumed that soil test potassium will be higher in the spring, this same demonstration data set shows that is often not correct.

Figure 1 - Management Cycle

True management of anything is a cyclic pattern. We often start with a soil test in the analysis phase, then make decisions on how and what to correct/improve. Followed by planning on how to implement those decisions. Then implementing the plan takes place. The real value in this model is on the next sampling cycle, taking the time to review the new data and determining if your goals of the previous plan were met, and if not, determining why. When soil samples are collected repeatedly at the same time of year, location, after the same crop, etc. to reduce the sampling variation, the changes in soil test values based on management become clearer.

When soil samples are collected in the same season as fertilizer is applied, all the management steps need to take place in 7 to 10 days during one of two busiest and stressful seasons, with no time to critically evaluate the data. The risk for mistakes, or less than ideal management decisions, increases using this short time frame. Sampling a season ahead of fertilizer application provides more time to evaluate the overall fertility management plan. For example, soil sampling in the spring provides the entire growing season to evaluate/refine the plan, make fertilizer purchases, prepare prescriptions ahead of time (yield data crop removal can still be added at harvest time), evaluate the crop through the growing season, and adjust based on crop prices, yields, and fertilizer prices. This leaves the only management step taking place during fall harvest is implementation of the plan.

When we let go of the notion that we need to collect soil samples in the fall and start looking to collect soil samples a season in advance of fertilizer application, the opportunities for increased and advanced management of soil fertility becomes possible.

March 04, 2022

Soil Sampling Depth - A Critical Piece of the Puzzle

When formulating a quality soil sampling plan, our focus is often directed toward parameters such as grid vs. zone, sample point locations, number of acres per sample, or number of cores per sample. However, a critical parameter that is often overlooked is sampling depth and the consistency of hitting the target depth every time. Cores that vary in collection depth by 1/2” – 1” or more can greatly impact the resulting data which translates straight to the bottom line when it is time to purchase and apply fertilizer inputs.

Nutrient concentration can vary greatly throughout the soil profile, especially under long term no-till conditions.Therefore reliable, consistent results can only be achieved when sampling depth is closely controlled. If you have employees or others helping in your sampling operation, make sure this topic is included and discussed in any training and instructions that you provide.

We often receive questions at the lab regarding sample collection in wet soil conditions.  Proper sampling can continue if good depth control can be achieved.  When the probe is placed into the soil, look in the top of the collection tube and ensure that the top of the soil core being collected is very near to the soil surface.  Under extremely saturated conditions the tip of the probe will not accurately cut through the profile and will push into the ground like a stake while compacting the soil around it resulting in inaccurate sampling depth.

Recommended sampling depth under varying cropping conditions are normally 4” in lawn and turf, 6” in no-till cropping and 8” in conventional tillage.  When choosing your desired sampling depth it is critical  to make your best choice for your conditions  and consistently sample at the same depth over time.  Most samples are collected every 2-4 years and the sampling depth must remain the same so that nutrient concentrations can be compared across collection dates and trends can be established.




Soil Test P

Soil Test K

















Long term no-till. LOI, Reported as Bray P-1, ammonium acetate K. Source ALGL 2021

As seen in the data table above, phosphorus, potassium and soil organic matter tend to decrease as sampling depth increases.

If you would like assistance with any of your sample collection plans, please contact our agronomy staff.

March 04, 2022

We Need Your Photos!

The ALGL customer photo calendar is becoming a tradition! This past year we celebrated the 5th issue of the calendar built by you. Over the past years it has been amazing to see how beautiful the world around us truly is though the eyes of our customers. 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 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 2023 calendar. Follow us on Facebook for voting details.

 Photo criteria 

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


  • Photo submission deadline is September 15, 2022
  • 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.
March 04, 2022

Basics of Lab Data Files

The lab data generated by ALGL is delivered to clients in a variety of formats for the use in software. One key distinction about these data files is that it is lab data only. There are data file formats that are dedicated to the spatial representation of lab data. We at the laboratory do not generate these files. In most cases the GPS coordinates of the sample location is not shared with the lab.

The most common data files are CSV files. They are identified by their file extension, .csv and are commonly called “comma delimited” files. These are basic text files in which the data for a given sample is contained in a single line of text, and each piece of data is separated by a comma. These files can be viewed, opened, modified in spreadsheet programs like Excel and text applications like Notepad, but must be handled within specific parameters to maintain the integrity of the file structure. Often critical metadata, which is information that provides context to allow the data to be understood by the end user, is not contained in the data file. This metadata includes such information as the type of data being presented (analyte), units, and extraction method. This is especially true because not all software packages require this information to be explicitly given within a data file.  

A growing data file format is the Modus-xml file. Modus is a standardized system of defined terminology, metadata, and file structures that has grown from a need to manage and exchange agricultural testing data. The file format follows an XML structure, which is essentially a coding language. The Modus files have a standardized data structure and use a preset list of codes to identify all parameters of the sample such as lab method and units.

We often get requests for shape files. This is not a single file, but rather a set of files, that are often grouped in a ZIP file. Each data set is contained in three identically named files with different file extensions of .shp, .dbf, and .shx. Each file contains an aspect of the complete data set. These files are specific to GPS/GIS mapped data. The GPS coordinates of the sample location are required to generate these maps.

Often software companies electronically share data about a soil sample or set of soil samples before they arrive at the lab. This data can be as simple as a grower/farm/field, or very detailed, and is often determined by the software’s data flow. In most cases a unique identifier (serial number) is assigned to the sample or set of samples. That unique identifier accompanies the samples to the lab and is used to link the electronic data that was sent by the software ahead of time to the physical sample.  This can also provide more efficient data entry for the customer and the lab.

When the lab results are released, they are sent to the customer in a couple of ways. Some data is simply emailed to the customer for manual import. Some data is emailed to a server, and the server automates the uploading of the data to the software. Data can also be sent directly from our server through an automatic interface that processes the data and imports it into the software platform.

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