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Nitrogen Release from Organic Residues

Nitrogen (N) is one of the most critical elements in all living organisms, and is often one of the most limiting nutrients in crop production. In addition, N is perhaps the most dynamic nutrient in the soil, and a number of factors can influence the amount, form and plant availability of N.

N can exist in a number of different forms in the soil. However, N is only available to plants as ammonium (NH₄⁺) or as nitrate (NO₃^-). Both NH₄⁺ and NO₃^- are inorganic forms of N, which simply means that they are not contained in an organic, or carbon based compound.

Organic materials, such as plant or animal remains or soil organic matter, contain N as an integral component of their structure. Much of this N is contained within organic compounds, and is therefore not plant available. However, when these materials are broken down by natural chemical and biological processes, much of the N is converted into an inorganic form and released into the soil solution.

 

The breakdown of organic N into inorganic N, a process called mineralization, is accomplished by soil microorganisms. These microorganisms consume the residues for energy and, in the process, release N as inorganic N compounds such as ammonium. Mineralization is affected by a number of different factors, including  soil temperature and moisture content, that affect the rate at which these soil microorganisms function.

One of the most critical factors is the composition of the organic residue. The amount of N in a residue can vary widely from one material to another, and this has a strong bearing on not only the amount of N released but also on the rate at which it will be released from the residue. The amount of carbon (C) relative to the amount of N in a material is expressed as the Carbon to Nitrogen, or C:N ratio of the material. Materials with a high C:N ratio, such as wheat straw, will have a tendency to break down slower than materials with a low C:N ratio, such as soybean stubble. In addition, materials with a high C:N ratio may temporarily decrease the amount of inorganic N in the soil in order for the soil microorganisms to have adequate N to function, a process called N immobilization.

The release of N from organic residues is a critical process in natural systems. While we generally consider this to be a less important process in agricultural systems because of our use of fertilizer N, most agricultural crops can still receive a large portion of their total N needs through this process. Therefore, understanding the basics of N release from organic residues is critical for successful fertility management.

 

A Day in the Life of a Soil Sample: Day 1

Editor's Note: Over the course of the next couple of months, we will be sharing an inside look at the processes which are used to turn a soil sample into useful and accurate data. We realize that by sending samples to us, our customers are putting their trust in us to deliver the right results, every time, on time. We strive to be a company built on integrity and partnership with our customers. We believe that it is important to be transparent with our process so our customers can be ensured that we do not cut corners. We realize that time is of the essence when it comes to getting results, but we will not report any data until we are confident that it was analyzed correctly. We do not want our laboratory to be a “magic black box” that takes in samples and spits out numbers. We are a company with a passion and understanding of agriculture. We understand what our customers are trying to achieve in the field, we hope this inside look provides a better understanding of our commitment to quality analyses.

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From the moment a soil sample arrives at the lab for a routine analysis, the whole process takes about 48 hours. This process is spread over 3 business days.

Day 1 for most soil samples begins at about 9:30 am when UPS brings the daily delivery. As the boxes are unloaded, the “layout” process begins. We group all boxes from each customer together to minimize the need to locate multiple boxes that contain a single set or field of samples. Each box is opened and the submittal form is located. The technician first checks which analysis is to be completed on the samples and moves any samples requiring non-routine analysis to another area for special handling. The routine samples are then unpacked and organized per the order specified on the submittal form. If any samples are missing, or the analysis package is not clearly indicated, the set of samples is set aside until our customer service representatives contact the customer for clarification or instructions on how to proceed. We will not begin any analysis until we are positive the customer is getting what they expect.

 

Once the samples are organized, the submittal forms are then sent to the office in the same order in which the samples were laid out to be logged into our computer system. The logging process starts with “stamping”. Stamping assigns a unique lab number to each sample. Each sample ID on the submittal form is manually stamped with an automatically advancing numbering machine. Information on the stamped submittal forms is then entered in to our database which ties together the lab number, sample ID, grower name, farm name, field name, and analysis package. After all the submittal forms have been entered for the day, the information is compiled into summary sheets called bench sheets which will be used on day 2 by the chemists and technicians as instructions on how each sample is to be analyzed. Some samples may need only one analysis while others may require 10 or more.

While the sample submittal form information is being entered, work continues in the layout room. After the samples have been arranged according to the submittal form and double checked, the samples are transferred from the shipping bags to drying bags. The drying bags are arranged on sections of wire shelving which fit onto carts capable of holding 200 samples. The combination of the paper drying bags and wire shelving helps speed up the drying process. The loaded carts are transferred from the layout room into our state-of-the-art soil drier. In adherence to standardized soil analysis methods, the soils are dried at a temperature of 104⁰ F or less. Our custom-designed drier can maintain this temperature as well as maintain a relative humidity in the single digits by cycling the air through the drying chamber several times per minute. Day one comes to a close and the samples spend the night in the drier so they will be ready for day 2.

Service with a Smile

Amanda (aka “Mandee”) Muñoz has accepted a new challenge within A&L Great Lakes Laboratories as a member of our Customer Service team.  Mandee began her career with A&L Great Lakes as an ICP technician in 2005. During her tenure, she has also worked with our water, nitrogen and carbon/nitrogen processes. 

She brings these experiences to her new role as a member of our Customer Service team, joining Julie Bruggner, whom many of you know. Mandee’s friendly, outgoing personality makes her a great addition to the team. Mandee and Julie work closely with our customers to ensure that their needs and questions are addressed quickly and with integrity.

In her spare time, she enjoys trying new restaurants in town, because there is always something new and exciting with them.  Of course, this is in addition to spending time with family and friends, and cheering for the Hoosiers.  Congratulations Mandee!!

Data Security

Laboratory data is an important and valuable asset. As an independent laboratory, it is important for us to assure our clients that their data remains their property, and that safeguards are in place to prevent information from being released to individuals not entitled to it.

We are occasionally requested by a client to send copies of reports or data files to someone else. We are very happy to do this, but are aware of the importance of this data. Our primary responsibility regarding the confidentiality of our reports is to our client that is invoiced for the services provided. That report may represent samples that were taken for a customer of our client, but the data is still the property of our client, not their customer.

In order to release data to another party, we require approval from an authorized representative of our client. The preferred method is by email or letter, but can be given via phone call if that is the most convenient. We recognize that this might be extra work for you, but we want to ensure that your information is protected.

If data is to be routinely copied to another party, information regarding this can be set up in our client database. If changes in client personnel or addresses occur, we need to be notified so that data is not sent to an incorrect address. Please contact the lab regarding your account if you need to verify or change who is authorized to receive your data.

Collecting Plant Tissue Samples

We put a great deal of effort and resources into ensuring quality with our analyses here at A&L Great Lakes Labs. We want the data that you receive from us to be of the highest quality so that it is of the most benefit to you and your operation. However, quality analysis is only one piece of the puzzle. Good quality data begins with a good quality sample, and how the sample is collected and handled after collection goes a long way to ensuring its usefulness.

Plant tissue testing can be a very valuable tool to use in your fertility program. However, there are a number of guidelines that should be followed to ensure that this information is useful to you.

1. Sample the correct part of the plant. The interpretations of plant tissue analysis have been developed based on a particular part of the plant, and that part can vary based on the crop and growth stage of the crop. For more information, please refer to our Plant Analysis Sampling Guide, available from our website.

 

2. Collect enough sample for analysis. The amount of sample to collect can also be found in the Plant Analysis Sampling Guide. The amount of material listed is generally a guideline to help ensure that the sample is representative, but is not a minimum requirement.

 

3. If the samples are extremely dirty, shake off any excess dirt or gently wipe the samples off. Washing of samples is generally discouraged, as this can affect the potassium (K) content of the material. If you do choose to wash the samples, do so soon after sampling and before shipping to the lab to reduce these losses as much as possible.

 

4. Place the samples into PAPER bags, never plastic! Paper bags allow the samples to breathe and preserve the integrity of the sample.

 

5. Include a completed Plant Tissue Submittal Form with your samples. Complete the form as thoroughly as possible to ensure that your report is accurate. Be sure to indicate the plant type and growth stage on the submittal form.

 

6. Pack the samples loosely into a box, and ship them to the lab as soon as possible. It is generally best to ship the samples so that they arrive at the lab within 2 days (samples shipped via UPS Ground generally arrive within two days when shipped from anywhere in the Great Lakes region). It is best to ship samples Monday-Wednesday, to reduce the possibility of samples being in transit over the weekend.

If you have any questions about plant tissue analysis, please contact your A&L Great Lakes regional agronomist or call the lab at 260-483-4759 and we will be happy to assist you!

Nitrogen Management with Replant or Thin Corn Stands

While talking to agronomists from all over the Great Lakes Region, we have heard questions focused on nitrogen loss, population counts, and how late various corn maturities can be planted, but might we be missing the key questions to maximizing profitability of the 2017 corn crop. It is time to take a hard look at our nitrogen plans and adjust them for reality.

The target corn yield of 200+ bu/acre of April may not be a realistic yield goal with the delayed planting. One positive thing about reduced yield goals because of late planting, replanting, or reduced stand populations is that the nitrogen required to achieve this adjusted lower yield goal is likely also reduced. Early spring preplant and starter nitrogen has likely been subject to loss due to the wet conditions, but has the loss of nitrogen exceeded the loss of yield potential? Most likely no, and if you have plans to side-dress, be certain to adjust your nitrogen rates for you new yield goals.

With pre-plant nitrogen, utilize soil nitrate and ammonium tests to monitor fields that might be at risk. One benefit to late planted corn is that side dress nitrogen applications will also be delayed, usually into a period with weather conditions that have a lower risk of nitrogen loss, thus leading to potentially greater nitrogen use efficiency. Help from your Regional A&L Great Lakes Agronomist is only a phone call away!

Gearing Up for PSNT

Nitrogen is the most elusive nutrient to manage and, when deficient, will significantly limit yield potential to a point that profits are lost. Having the right amount of nitrogen available at the right time is essential to achieving profitability.

A corn plant uses around 10% of the nitrogen it needs during the first three weeks of growth. Then, during the next five weeks (V4 to V18), it needs to take up 65% of its total seasonal nitrogen requirement. If nitrogen supply is limited during this period, yield and profits will suffer. Taking a pre-sidedress nitrate test (PSNT) at the V4-V5 stage indicates how much nitrogen is available in the soil from cover crops, legumes, applied manure and other organic sources.

Timing is very important; samples should be taken five to ten days before sidedressing to allow time to collect the sample, have it analyzed and receive the results. Samples taken too early will not be as accurate because nitrogen is continually released (mineralized) in the spring as the soil warms.

A&L Great Lakes analyzes PSNT samples and reports results the next business day after receipt. PSNT soil samples should represent no more than 20 acres. The sampled area should be consistent for past crop, soil types and manure applications. Sample the soil 12 inches deep, taking 15 to 20 cores per field. Avoid probing through the starter band. If fields have significantly differing soil types or drainage patterns, sample these areas separately. In addition, it is generally not recommended that these samples be analyzed as a part of a basic soil test, because of the differences in recommended sampling depth.

More information on the PSNT, including information on sampling and sample handling, is outlined in our PSNT Fact Sheet, which is available from our website.

A Breath of Fresh Air

What is the most effective and dramatic way to clean up an area?  Renovate, replace and redecorate.  Keeping our instrumentation and computer equipment on the cutting edge has always been a priority at A & L Great Lakes Laboratories, but our work areas often get left behind.

The old office furniture, installed more than 25 years ago, served us well, but had outlived its useful life, and was badly in need of repair and refreshment. We began by removing the old furniture, flooring, and ceiling tiles.

 

A fresh coat of paint, new flooring, and replacing the ceiling tiles made everything look a lot better!

The project was finished off with new, modern office furniture to better meet the needs of our staff to ensure that they are better able to serve our customers.

We invite you to check these spaces out the next time you are at the laboratory.  The completed project has been rewarding as many employees were not afraid to get their hands dirty and assisted with demolition and painting.  Great pride and ownership has been taken of these areas and will serve our employees and guests well for many years to come.

Employee Spotlight: Meet Patti Knuth

Patti has been with us for almost 30 years of combined service (she took a short 4 year break 12 years ago). She is the voice of our company-- chances are if you have called us, you have talked to her.

She started in the lab, analyzing plants, feeds, and manures. Now she answers customer questions and helps with issues. She loves our customers. When asked what her favorite part of her job is, she said pleasing customers. What a great ambassador to have in our customer service role!

In her spare time, she likes to ride her bike on the Fort Wayne Trails and you can often catch her at the Trek The Trails events on Tuesday nights throughout the summer.

Spring Sampling Considerations

We frequently get the question at the lab; “When is the best time to take a soil sample?”  Soil fertility is not static.  Soil test levels fluctuate naturally through the year as nutrients are taken up by growing plants and returned from residue.  Application of fertilizer, manure or other nutrient sources increases the amount of crop nutrients, causing soil test levels to increase immediately after application.  During the growing season, soil test levels will decline as nutrients are taken up by plants.  Overall, if the application rate approximates crop needs there will be a minimal effect after nutrients in crop residues or cover crop are returned to the soil through decomposition. To minimize the effects of these processes on soil test levels, it is commonly recommended that soil samples be collected at approximately the same time of year each time a field is sampled to reduce variability introduced by the normal crop growing cycle.

While the results of a single soil test can provide information needed to define the fertility program for a given area for the coming set number of years, the real value comes from looking at the data collected from several sampling events, taken at a similar point during the growing cycle, and identifying the trends in the soil test values.  For example, if a soil sample is collected and the resulting data shows a lower than desired fertility level, we may need to apply more fertilizer for the next crop.  If soil test values increase toward a target level over sampling cycles, it indicates the fertility program is working as intended.  The fertility program would need to be adjusted if soil test levels are trending lower or higher than intended.

Traditionally, fall has been the most popular time within this region to soil sample, with nutrient application made soon after.  Fall soil sampling and fertilizer application requires several steps:

• Field is harvested
• Service provider contacted about sampling the field
• Service provider coordinates soil sample collection
• Samples are collected
• Samples sent/delivered to the lab
• Samples processed and analyzed by the lab
• Soil test results sent to the service provider
• Soil test results used to generate fertility recommendations
• Fertilizer ordered and tendered to the field
• Fertilizer is spread
• Fertilizer incorporated if tilled

With many steps condensed into a short time period and with often less than ideal weather forecasts, things must happen quickly.  The soil fertility program is a critical investment that has a major impact on a grower's bottom line, and making decisions related to the program should be done with great care.  It is hard to optimize a rushed management decision.  

More are switching to spring soil sampling to reduce this time crunch.  Samples can be collected throughout the spring, even in the planted crop.  Soil test data can be processed so that fertilizer and lime applications can occur immediately after harvest.  Crop conditions and weather during the growing season can be also evaluated to further refine soil fertility programs. There is considerable value to sampling well ahead of the fertilizer application season, providing time and flexibility to make better fertilizer management and purchasing decisions.