News

What Tissue Test Will and Will Not Tell You

Tissue testing has long been utilized as a diagnostic tool but is increasingly being used as part of the overall crop fertility management. This concept is helping agronomists and growers find more effective and efficient ways to provide plant nutrition. It is easy to read too deeply into tissue test result, while missing basic issues. There are a couple of basics to keep in mind when reviewing plant tissue data. In many cases, observation of the crop leading up to sampling is key.

Less than 15% of the plant dry biomass is represented by tissue test data. Much of a plant dry biomass is carbohydrates comprised of carbon, hydrogen, and oxygen that is not reported in the tissue test data. As the carbohydrate content of the plant goes up, the percentage of the plant represented by the nutrients on the tissue test decrease.  A plant that is stunted or stressed due to environmental impacts that do not directly impact the update of nutrients can result in overall normal to high tissue test data values.

Plant growth patterns can impact tissue test data. Just prior to a rapid growth phases, plants accumulate nutrients in preparation. At this point tissue test results tend higher. Once the plant enters the period of rapid growth, the plant begins to accumulate carbohydrates very quickly. These additional carbohydrates effectively dilute the nutrient content of the plant biomass. These growth patterns can also shift the mobile nutrients in, and out, of the plant segment being sampled.

A tissue test is a snapshot in time. It is an evaluation of the nutritional status at the time of sampling. This will reflect the nutrients the plant was able to access in the past but does not give any indication at to predicting nutrient values into the future. This a key reason why management systems with a defined focus on tissue testing a part of an overall fertility plant promote repeated sampling of the same area through the growing season.

Repeated tissue testing of the same area can show how any seasonal patterns and plant development may impact the crops’ ability to access nutrients through the growing season. To make valid assessments of the tissue data, weather data, along with crop observations, are key. For example, periods of dry weather can reduce nutrient availably to the plant, soil water is essential in nutrient movement to and into the plant. Dry weather with normal growth, resulting in normal carbohydrate accumulation, will normally lead to slightly lower nutrient vales in tissue tests, especially nitrogen and potassium. If the dry weather is severe enough to effectively stop plant growth, resulting in reduced carbohydrate accumulation, the tissue test could come back normal to high.

A tissue test can tell you what nutrient is missing in the plant but cannot tell you why. Was the plant unable to access the nutrient, or was the soil void of the nutrient? Often the first instinct is to apply the nutrient that was low in the tissue test. In this situation it is recommended to retest later to see if the nutrient application corrected the issue. A second recommendation is to take a soil test from the same sample locations as the tissue samples to identify if the nutrient is low in the soil or could something like soil pH be impeding the availability of the nutrient.

Do not get too wrapped up in ratios of nutrients in the plant. If a nutrient included in the ratio is deficient, the ratio will be skewed towards the opposite value. This can be seen with or without a calculated ratio if target for normal levels for a given nutrient are included. Ratios do help bring attention to these variances. For example, if one of the nutrients in the ratio is very close to the bottom of a normal or target level, while the other is high the ratio may alert you to abnormality a bit sooner than looking only at the individual nutrient ratings. The reporting of a ratio does not specifically mean there is an interaction between the nutrients.  A good analogy is a brick wall. A brick wall has a defined ratio of mortar and bricks. If you have more bricks, you cannot build any taller of a wall, and the extra bricks don’t impact how much mortar it takes to build the wall.

Trying to predict yield or any future values from tissue testing is difficult. There are more factors than plant nutrition that can impact plant growth and the final yield. If you are looking to start plant tissue test monitoring this growing season, contact your ALGL regional agronomist for details on our plant monitoring program before the sampling season begins. Contact your ALGL regional agronomist with any other questions or tissue testing needs.

How Quick Can I Expect Pelletized Lime to Change Soil pH?

Can I apply pelletized lime at planting and expect it to address my low soil pH rapidly in-season? While pelletized lime provides many benefits, such as quickly altering soil pH and possessing handling qualities that can make the application of the product more versatile, it has some limitations.  

A traditional pelletized lime is a uniformly finely ground lime that has been pelletized using a binding agent. The chemical makeup of the lime material, final grind, and the binding agent can impact the rate of soil acidity neutralization. All these factors influence the rate in which the carbonate material becomes water soluble, and reactive with hydrogen ions, to neutralize the acidity. Likewise, the rate of reaction is impacted by soil incorporation and soil moisture.

The figure below (Jones and Mallarino, 2018) shows the relative rate of acidity neutralization as impacted by the fineness of a calcitic ag lime. If only the finest ground particles were applied to the soil, the rate of soil pH adjustment would take place quicker than a blend of particle sizes. In addition, the pelletizing of the finely ground lime greatly increases the uniformity of spreading and handling characteristics in fertilizer systems designed to handle granular fertilizer.

This data was generated from an experiment conducted in a laboratory to control the environmental factors/conditions so that the research is repeatable. Primarily maintaining a constant soil temperature and moisture at 80-90% of field capacity. If we were to move this study to a field, fluctuations in temperature and soil moisture would impact the data. Lower soil temperatures and drier soils would slow the rate of reaction, especially for the more finely ground fractions.

The figure below from the same study (Jones and Mallarino, 2018) shows the relative rate of acidity neutralization as impacted by the product used. The results of the pelletized lime closely follow the results from the 60-100 mesh grind. Faster than traditional ag limes, but still slower than pure calcium carbonate when applied at equal rates.

Both the pelletized lime and the calcitic lime has similar pH impacts for the first 21-35 day of this experiment as the finely ground portion of the calcitic lime reacted similar to the fine grind of the pelletized lime.

This figure also shows that while pelletized lime increases soil pH more than calcitic lime when applied at equal rates, it also takes pelletized lime in excess to 100 days to reach a maximum soil pH adjustment. That is a over 3 months, or slightly longer when taking field environmental factors into consideration. If the pelletized lime is applied at planting the first of May, maximum pH will be achieved the bringing of August at the earliest. By this point in the season altered nutrient uptake and growth may have already negatively impacted crop yield.

If pelletized lime is routinely applied every year, timing is not critical. If this is a recue application of pelletized lime to make a quick pH adjustment to a neglected field to avoid yield loss, fall to late winter application of the pelletized lime prior to the growing season will have a bigger impact on in-season soil pH levels when compared to an at-planting application. While pelletized lime is a very useful tool in fertility management, it still takes time for pelletized lime to make meaningful soil pH adjustments.

Source: Jones, John D., and Antonio P. Mallarino. “Influence of Source and Particle Size on Agricultural Limestone Efficiency at Increasing Soil PH.” Soil Science Society of America Journal, vol. 82, no. 1, 2018, pp. 271–282., doi:10.2136/sssaj2017.06.0207.

Checking for Consistency from One Sampling Event to the Next

Most progressive precision soil sampling programs are sampling fields on a 2- or 3-year cycle. Often in the course of 2 to 3 years, there have been changes in the personnel or equipment used to collect those samples. There are a few clues in your soil test results that can be examined to validate if those samples were collected consistently.

The first clue to check is the organic matter level. The organic matter has the least potential to change significantly over the course of a few years. Even under intensive management to increase organic matter, such as no till, cover crops, and residue management, it is unlikely to see the soil test level increase by more than 0.1% per year on average. Any drastic change in organic matter levels likely indicate inconsistent sample depth, contamination of the sample with crop residue or manure, or an inadequate number of soil cores being collected to make up the sample.

The cation exchange capacity (CEC) should remain relatively consistent from sampling event to sampling event. The CEC is a measurement of the negative charge in a soil which comes from the clay mineralogy and organic matter that make up the soil. These 2 factors do not noticeably change in just a few years. On a routine soil analysis, the CEC is calculated from the extractable levels of calcium, magnesium, potassium, and hydrogen. Calcium and magnesium are generally the greatest contributors to the CEC. Unless extremely high rates of lime or gypsum have been applied, these 2 nutrient levels generally stay consistent resulting in a consistent CEC calculation.

Surprisingly, one of the numbers on your soil test that should not drastically change from sampling one sampling event to the next is phosphorus (P). Assuming your soil test P is at an agronomically desirable level, a high yielding corn or soybean crop are not likely to lower your soil test level more than 4 or 5 ppm in a single growing season. If the soil test P level changes more than 10—15 ppm between routine sampling events, it may be the result of inconsistent soil sampling procedure.

To truly compare soil test results from one sampling to the next, it is critical to minimize the variability. To do so soil needs to be sampled to the same depth, following the same crop, at the same time of year, and consist of at least 8 cores.

If you have any questions regarding irregular soil test results, please contact your ALGL agronomist.

Fertilizers and Plant “Availability”

Over the last few months, the ALGL agronomy staff have received many questions regarding different fertilizer products and whether the nutrients are plant available or how long it takes them to “release” the nutrients. The simple answer is that most fertilizer products are highly water soluble, and once they dissolve, the nutrients are in a plant-available form. However, this does not necessarily mean that the nutrients will be taken up by the plants right away. Below we will discuss the potential fate of the nutrients in a few common fertilizer materials if it is not taken up by the plant.

Most questions regarding nutrient availability are concerning phosphorus (P), MAP and DAP. Both products are more than 90% water soluble and are immediately in a plant available if there is adequate soil moisture. However, the P must be near an actively growing plant root to be taken up. So, what happens to the rest of the P if it is not taken up immediately? Much of the applied P will be loosely bound to the clay minerals through a process called adsorption. This fraction of the P can be released back to the soil solution as P concentrations are reduced through plant uptake. However different soil types can bind the P more tightly than others. Soils that are likely to bind P rendering it unavailable are soils with high clay content, high pH, and low soil test P.

Potassium (K) fertilizers such as potassium chloride and potassium sulfate also dissolve rapidly into the soil solution and are immediately in a plant available form that can be utilized by actively growing plants. A portion of the K will be held by the cation exchange capacity (CEC) of the soil and will be released as the K dissolved in the soil solution becomes depleted. The potential exists for the K to be lost to leaching or runoff if the K was applied in excess of the soils capacity to hold it or if there is no actively growing crop to utilize it. Soils most prone to K losses are high sand/low clay content soils, and soils with high organic matter.

The two most common dry nitrogen (N) fertilizers are ammonium sulfate and urea. Ammonium sulfate delivers nitrogen in a form that is immediately plant available. Since ammonium has a positive charge and can be held by the soils CEC, just like K, ammonium is generally considered the more stable form of plant available N. Urea, though it dissolves rapidly, is not in a plant available form initially. Urea requires an enzymatic reaction with urease to become ammonia, which quickly converts to ammonium to become plant available. If the N stays in the ammonium form, losses of N are minimized. Nitrogen losses occur when soils are warm enough for microbial activity to start converting the ammonium to nitrate. While nitrate is also plant available, it is a negatively charged so it is prone to leaching as it is repelled by the soil CEC.

The bottom line is that the best way to ensure adequate nutrient availability for your crops is to maintain good soil test nutrient levels and a desirable pH for and follow the 4R’s of nutrient management. Application of nutrients just prior to crop uptake reduces the potential for nutrient tie up and possible loss. If you have any questions about your specific crop and fertilizer situation, contact your ALGL agronomist.

Winter Wheat Nutrient Management Update

Winter wheat in southern Indiana and Illinois is beginning to break dormancy and  enter the spring regrowth phase and, as growth rates increase, so do nutrient demands of the developing crop. While a limited number of top-dress applications have taken place in southern parts of the Great Lakes region, recent rains and wet soils are limiting the opportunities for planned field operations. This has many wheat growers considering the best time for making a top-dress application to maximize benefit to the crop.

Information published by Charles Mansfield and Stephen Hawkins with Purdue University Extension suggests that nitrogen top-dress applications should be targeted for the early green up period as wheat comes out of dormancy when making a single application.  On sandy soils, a split application may be beneficial to wheat development, with the second application planned near boot stage.  When conditions prevent timely operations, nitrogen can be applied as late as heading, but yield will likely be limited due to nitrogen deficiency during vegetative growth stages.

Table 1. These recommendations are for mineral soils with adequate drainage and 1 to 5% organic matter, with wheat planted within 7 days after fly-free date last fall.

Wheat nutrient uptake demands in early spring are increasing at a time when temperatures are normally low, microbial activity is suppressed, and the soil has a limited capability for supplying nitrogen, sulfur and other key nutrients.  Timely plant tissue analysis can be used to monitor the status of the crop and fine tune management decisions to maximize yields.

Consistent Soil Sampling

Most progressive precision soil sampling programs are sampling fields on a 2- or 3-year cycle. Often in the course of 2 to 3 years, there have been changes in the personnel or equipment used to collect those samples. There are a few clues in your soil test results that can be examined to validate if those samples were collected consistently.

The first clue to check is the organic matter level. The organic matter has the least potential to change significantly over the course of a few years. Even under intensive management to increase organic matter, such as no till, cover crops, and residue management, it is unlikely to see the soil test level increase by more than 0.1% per year. Any drastic change in organic matter levels likely indicate inconsistent sample depth, contamination of the sample with crop residue or manure, or an inadequate number of soil cores being collected to make up the sample.

The cation exchange capacity (CEC) should remain relatively consistent from sampling event to sampling event. The CEC is a measurement of the negative charge in a soil which comes from the clay mineralogy and organic matter that make up the soil. These 2 factors do not noticeably change in just a few years. On a routine soil analysis, the CEC is calculated from the extractable levels of calcium, magnesium, potassium, and hydrogen. Calcium and magnesium are generally the greatest contributors to the CEC. Unless extremely high rates of lime or gypsum have been applied, these 2 nutrient levels generally stay consistent resulting in a consistent CEC calculation.

Surprisingly, one of the numbers on your soil test that should not drastically change from sampling one sampling event to the next is phosphorus (P). Assuming your soil test P is at an agronomically desirable level, a high yielding corn or soybean crop are not likely to lower your soil test level more than 4 or 5 ppm in a single growing season. If the soil test P level changes more than 10—15 ppm between routine sampling events, it may be the result of inconsistent soil sampling procedure.

To truly compare soil test results from one sampling to the next, it is critical to minimize the variability. To do so soil needs to be sampled to the same depth, following the same crop, at the same time of year, and consist of at least 8 cores.

If you have any questions regarding irregular soil test results, please contact your ALGL agronomist.

It's Calendar Time Again!

Have you enjoyed our customer photography calendars the past few years? Do You have photos to share? We are excited to announce that we are launching our fifth year of the customer photo calendar!  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. We will select our favorite pictures and invite our followers on Facebook vote on their favorite to be on the cover of the 2022 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.

Rules 

• Photo submission deadline is September 15, 2021
• 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.

The 2020 Annual Soil Test Summaries Are Available

The 2020 annual soil test summaries are available on the ALGL website at https://algreatlakes.com/pages/2020-soil-test-summaries. Your regional ALGL sales agronomist has access to regional trend graphs that show the change in soil test values from 1996 to 2020 for the Great Lakes Region, and individual states, that they can share for use in presentations and meetings as needed.

For those customers accounts that analyze more than 20 soil samples or 10 plant samples a year, soil and tissue test summaries are available for the account. Those summaries can be found on eDocs at https://docs.algreatlakes.com/login.aspx. Be sure to adjust the eDocs’s data filters to include “Summary” as the document type and the time filter to span December 31, when the reports were posted.

These same customers will also find a trend graph of these summaries over time, and a soil sampling history report that summarizes all the field that were sample in that given year. These soil sampling history reports are a great tool when routinely sampling on a 2-, 3-, or 4-year standard rotation. For example, when preparing to soil sample in 2021 on a 2-year cycle, go back to the 2019 Soil Sampling History Report for a list of fields that are due to be resampled in 2021.

Industry Group Formed to Advance Agriculture Nutrient Management in the United States

December 2020 - Bloomington, Illinois - The Agriculture Laboratory Testing Association (ALTA) is an industry organization committed to ensuring the quality of data to agricultural communities through encouraging the development, use, and acceptance of proven agricultural testing methods.

• In December 2020, the Illinois Soil Testing Association became the Agriculture Laboratory Testing Association.
• The Agriculture Laboratory Testing Association's primary objective is to promote high-quality testing data to improve farm production, profitability, and sustainability.
• To meet this objective, the Agriculture Laboratory Testing Association offers two Certifications: ALTA- SAC (Soil Analysis Certification) and ALTA-PAC (Plant Analysis Certification)

As a result of continued growth over the last 30 years, the Illinois Soil Testing Association (ISTA) re-branded itself as the Agriculture Laboratory Testing Association (ALTA) in December 2020. This industry organization will be a leader in ensuring consistency, precision, and accuracy across agriculture laboratories nationally. ALTA plans to reach this goal through outreach, education, and certification programs.

"The Illinois Soil Testing Association (ISTA) has changed its name to the Agricultural Laboratory Testing Association (ALTA) to reflect the scope and territories that our membership serves.  Our member laboratories offer a broad range of agricultural testing and services across the United States.  ALTA's mission is to support all types of agricultural testing laboratories so they may provide the best analysis and information.  We will support that mission by providing education and certification programs that help ensure quality and innovation in our industry."

Tim Smith, CropSmith, Inc., Laboratory Owner, ALTA President, Farmer City, IL

ALTA has developed two certification programs, one for soil analysis (SAC, Soil Analysis Certification) and another for plant tissue testing (PAC, Plant Analysis Certification). These programs were initially created by the Illinois Soil Testing Association and have earned respect in the region for creating a high standard for testing quality.  These programs' objective is to assure soil and plant analysis provided to Ag producers nationally are within laboratory statistical norms (consistent, precise, and accurate).  Based on this premise, certifications help ensure labs follow the U.S. Department of Agriculture Natural Resource Conservation Services (NRCS) code 590 of nutrient management guidelines for testing and recommendations.

"ALTA is a very important organization for our company because it provides validity to our test data and demonstrates to our customers that we can produce accurate results.  The meetings offer members targeted education and a collective forum for the exchange of ideas focused on the agricultural laboratory."

Greg Neyman, A&L Great Lakes Laboratories, Director – Green Industries Division, Fort Wayne, IN

 ALTA is positioned to lead the agriculture testing industry nationally, driving the discussion around how to ensure precision and accuracy of agriculture data moving into the next decade. Providing educational opportunities for members, engaging the public, and offering relevant certification programs are methods ALTA will help member companies grow while creating a sustainable future.

"The ALTA organization provides a forum for agronomists and testing laboratories to educate and advance Agriculture nutrient management in the United States.  Through workshops and laboratory certification program for soil and plant analysis, ALTA sets a standard of professional excellence."

Robert O. Miller, Ph.D. ALP Technical Director, former Affiliate Professor Colorado State University, Fort Collins, CO

 In 1981 the Illinois Soil Testing Association (ISTA) was founded to help address Illinois growers' need for quality soil test information.  Over time the group grew to represent the region and was re-branded in 2020 as the Agriculture Laboratory Testing Association (ALTA).  ALTA's primary objective is to promote the interests of the agriculture testing industry in the United States and promote high-quality testing data that will improve farm production, profitability, and sustainability. ALTA works towards this goal by creating educational opportunities and laboratory certification programs.

Find Out More:  https://www.alta.ag/

Living Up to the Boy Scout Motto

A quick count through the calendar pages reveals 100 days until April 1 and the Boy Scout motto would remind us to plan well and be prepared to handle the spring planting tasks as accurately and efficiently as possible.  Much time and effort has gone into cropping plans, seed selection, soil sampling, fertilizer plans and data analysis since harvest but here are a few additional items that might pay big dividends during the heat of the battle next spring.

Create a list of the key vendors and retailers that will be involved with your operation and reserve some time to visit with each one and discuss your communication plans.  Employees that you have worked with in the past may have taken other responsibilities and new employees may be filling important service rolls and will play an important role this cropping season.  It is a good time to update phone contacts, email addresses and learn the preferred method of contact and the main responsibilities for key individuals.

Provide your vendors with names and contact information for your staff and their responsibilities such as field prep, fertilizer applications, herbicide management, planter operation and data management.

Discuss field maps and cropping plans with each one and point out best routes to access fields, best field entrances, preferred loading areas and best places to park equipment that is left overnight or parked during a weather delay.  Remind them of safety concerns such as overhead powerlines that may interfere with applicator booms, narrow field entrances and low weight capacity bridges that may not be suitable for trucks and equipment.  As much as possible, try to direct traffic away from homes, children’s play areas and light vehicle traffic.  Keep heavy equipment away from underground obstacles such as water meters, septic systems, drainage systems or other utilities that may not be designed to support heavy loads.

Consider data handling and transfer for items such as variable rate maps/recommendations, planter files, hybrid and variety selections and any operating files that may be needed for herbicide applications.  Consider sharing desired GPS headings, field obstacles or auto steer navigational information that will assist vendors in their work.  Have a plan in place for sharing needed electronic data with the proper operators at the proper time so equipment is prepared to run when the time is right.

Please keep the lines of communication open and help everyone implement the plan as safely and efficiently as possible this spring.