News

Challenging Conditions and Nitrogen Timing

Depending on each farm’s source for fertilizer recommendations, and crop requirements, each crop is going to need a certain amount of nitrogen.  In this example, corn will be the crop of focus.  Once again most of the Midwest Corn States have been experiencing an unfavorable, wet spring for 2024.  This has led to many challenges, and applying a pre-nitrogen application is not an exception.

                Even though most fieldwork has been on standby, today’s modern farming technology allows growers to remain agile.  For most, the understanding of dispersing risks of applying all, or most, of their crop’s fertilizer needs throughout the growing season is self-explanatory.  What happens if one of the applications is missed due to poor weather?  Split applications greatly reduce this risk and can be made up elsewhere.

                The top priority, being good stewards of the land, are implementing the 4Rs.  These Rs stand for: right rate, right source, right placement, and right time.  Even though some will apply certain nitrogen products in the fall, or early spring, keeping the nitrogen application as close to or during the growing season is always the right choice.  This best utilizes the farmer’s inputs and can lower application rates.  There are many different approaches to obtaining full season application rates while missing, in this example, a pre-nitrogen application due to challenging weather conditions.

                The first situation would allow for fertilizer application while seeding.  For corn this is generally through an in-furrow tube, off-set incorporation (2x2), dribble tubes, or other types of liquid injection (dry fertilizer in other parts of the world).  In-furrow tube options can range from application directly on, under or between the seed.  While this is great for starter applications such as 6-24-6 or 10-34-0, they are not able to apply high enough nitrogen amounts without causing significant injury to the germinating seed.  Dribble tubes are usually placed toward the rear of the row unit on the planter.  This is because anything placed in front, or midway, can splash product on the unit causing corrosion and premature failure to any unprotected metal or electrical components.  They are the cheapest option for fertilizer applications on the planter, but dribble tubes do not obtain the right placement. 

Off-set incorporation needs to be a rather broad category.  This is utilizing a knife, coulter, or disc to open a channel at any given distance from the seed furrow and placed below the soil surface.  For planter options, this gives the ability to use higher rates since it is not located as close to the seed.  2x2 is amongst the most popular setups.  The channel is placed two inches to the side of the seed and two inches below the seed furrow.  There are many different options for distances and depths, but for the planter pass to be the first fertilizer application of the year a 2x2x2 option is growing in popularity.  These setups are placed on both sides of the furrow and can allow for 60-80 units of nitrogen in a single pass while seeding.

This is just one pass to a fertilizer management plan.  To obtain the season’s total nitrogen needed, for growing a corn crop, in-season passes will need to be conducted.  This may include nitrogen sidedress applications, and potentially multiple times, or the use of a high-clearance system.  It is important to always incorporate nitrogen applications.  If the nitrogen is left on the surface, or unprotected, it has a greater risk of volatilization before it can be made accessible to the plant’s roots. 

Applying Pelletized Lime at Planting

While pelletized lime reacts faster than standard ag lime, it does have its limitations. It takes 3-5 months for pelletized lime to reach maximum adjustment of soil pH. The key difference between pelletized lime and standard ag lime is finless of grind. Pelletized lime is standard ag lime that has been ground to a much finer and uniform particle size that solubilizes and reacts quicker. The material is then pelletized using a binding agent to make a more application flexible product.

If the goal is to make small annual applications for pelletized lime to maintain pH over time, the timing of the repeated application of not an issue. If the goal is to correct a very low soil pH to reduce impact on the next cropping season, timing of application is very important.

Pelletized lime works very well when applied in the fall resulting in a notable soil pH increase by spring planting that should carry though the growing season. The closer to planting the material is applied, the less impactful it is soil pH increase in that growing season. Very early spring applications will have a significant impact on soil pH mid growing season. Applications made at planting will have a significant impact on soil pH during reproduction and grain fill. 

Pelletized lime applied in the fall, in combination with fall application of standard ag lime, is a very effective way to increase and hold soil pH relatively quickly. The pelletized lime will react and have a significant impact on soil pH the following growing season starting sometime in the spring. The pelletized lime will maintain an elevated pH until the standard ag lime reaches peak pH adjustment 12-24 months after application.

Double Crop Soybean Management

As we are planting our full season soybeans, it is also time to start planning for double crop soybeans. Historically double crop soybeans after winter wheat were not encouraged north of I-70. In recent years reports are growing of successful double crop soybeans as far north as U.S. Hwy 30.  While many are familiar with some of the basic management suggestions for double crop beans, the fertility implications of the beans are often overlooked.

The key to double crop soybean yields is to get the crop off to a strong start as early as possible. To do this cut your wheat as early as possible. If there is the ability to dry the grain or grain moisture discounts are not prohibitive, consider cutting wheat at a higher grain moisture. Baling the straw is often a question of debate and most often is based on the ability to manage/handle residue at planting. Uniform seed depth and seed to soil contact is much more important in double crop beans due to the reduced likelihood of steady rains to overcome planting errors. In the event of heavy rain near double crop planting time, be sure to have good soil conditions for planting. A day or 2 earlier planting will not overcome the negative impacts of planting too wet.  There have been reports of increased yield by cutting the wheat low when baling, the shorter straw reduces shading of small soybeans and reduces water transpiration rates out of the soil through the standing straw.

Large acres of double crop soybeans can be challenging to harvest as you move north. Planting soybean varieties near the top end of the suitable maturity is advisable to maximize yield. This means the soybeans will be harvested late, often in the late fall when drying conditions are not conducive to soybean harvesting. Focus on those fields with better fertility. Good phosphorus levels will promote good root development to help access moisture and nutrients in the drier months of the summer. Good potassium levels will help the soybean plant better utilize water in the hot/dry summer months.

Fertility is often the most overlooked aspect of double crop beans. While often the focus is on the nutrient removal of the wheat straw, a strong double crop soybean crop will remove a significant amount of potassium. Be sure to take the straw and the double crop beans into the crop removal consideration when determining nutrient recommendations.

Figure 1. Nutrient removal amounts and associated cost when baling straw.

What is ENR?

ENR stands for Estimated Nitrogen Release. This is a calculated estimation of how much potential nitrogen may be released from soil organic matter (SOM) in one year. The actual amount and time of nitrogen release is dependent on the composition of the organic matter, soil moisture, and weather.

ENR is a calculation from the soil organic matter value on a soil test. Soil organic matter is reported as the percent of organic matter by weight. ENR is a calculation that is based on a couple of basic concepts regarding soil and the composition of soil organic matter. While these concepts are rooted in scientific research, they can vary.

The first concept explains that an acre of soil weighs approximately 2 million pounds. This is a rough estimation of the soil weight that is tilled/turned when an acre is plowed to the depth of a “standard” moldboard plow, which is assumed to be 6 2/3 inches. Using this standard value of 2,000,000 pounds per acre, we can approximate the amount of soil organic matter in an acre of soil, based on the percent of organic matter found through a soil test. For example, if a soil has an organic matter level of 3%, we can use the 2,000,000 pounds per acre value for the weight of the soil to calculate the total amount of soil organic matter per acre:

2,000,000 x (3/100) = 60,000 pounds of soil organic matter

The second concept states OM is approximately 5% nitrogen by weight. This may vary slightly based on several factors including soil type, management, and composition of the soil organic matter. From our previous example using soil with a 3% organic matter level:

2,000,000 x (3/100) = 60,000 pounds of soil organic matter (SOM)

60,000 pounds SOM x (5/100) =  3,000 pounds of N/acre

While this seems like an impressive value, unfortunately not all the nitrogen is available to the growing crop in a given year. The release of nitrogen from soil organic matter, a process referred to as mineralization, is a biological process that is facilitated by microorganisms within the soil. These microorganisms break down soil organic matter and, in the process, release nitrogen (along with other nutrients) into the soil solution where they can be utilized by the crop. However, the rate of mineralization is not particularly fast, and is governed by many factors. This makes it quite variable year to year. Therefore, it is assumed that only 2 to 4% of the nitrogen in OM will become available in any given year. From our previous example:

2,000,000 x (3/100) = 60,000 pounds of soil organic matter (SOM)

60,000 pounds SOM x (5/100) =  3,000 pounds of N/acre

3,000 pounds N/acre x (2/100) = 60 pounds available N

3,000 pounds N/acre x (4/100) = 120 pounds available N

60-120 pounds available N / acre

 Weather conditions that promote strong plant growth, such as warm temperatures and adequate soil moisture, are also beneficial in the conversion of SOM to plant available nitrogen. Therefore, in those cropping years where weather conditions favor strong yields, they also tend to favor higher mineralization rates. These factors cause greater releases of N from soil organic matter. This greater rate of N release can therefore serve as a kind of buffer, supplying more N to a crop that could essentially benefit from higher nitrogen rates.

Determining a nitrogen application rate that is economically and agronomically optimum can be challenging when the soil has a higher OM content. For example, the nitrogen release from organic matter in a field with 6% OM can range from 120 pounds/acre to 240 pounds/acre. The variation of the nitrogen released is often weather dependent during the growing season and causes challenge when determining nitrogen application rates.

Note - Organic soils, those with greater than 20% SOM, were able to develop over time due to reduced SOM decomposition. Saturated soil conditions for a portion of the year slows SOM decomposition in organic soils, thus reducing the mineralization of nitrogen. Those organic soils that have artificial drainage may experience a higher ENR than those that are not drained, but at a level less than determined by the ENR calculation.

Mycorrhizae - A Soil Amendment?

In various gardening, lawn, landscape and commercial agriculture communities, mycorrhizae have been a topic of discussion for quite some time.  There are many questions surrounding the relationship between mycorrhizae and plant nutrient uptake.  Before addressing these questions, an understanding of what it is and how it operates will be beneficial.

Mycorrhizae are a fungus that grows and reproduces in the soil from spores that colonize the roots of plants, forming a mycelium network around and within the root cells.  It has been referred to as, the “hidden half” of plant life, and often overlooked aspect of the ecosystem.  These relationships between fungi and plant roots play a fundamental role in nutrient uptake, plant health, and ecosystem stability.  Who wouldn’t want more present in their soils? 

There are different types of mycorrhizae.  Rather than getting into the scientific names of each, they can be distinguished by two types.  The first type is ectomycorrhizae.  These form a dense sheath around the roots and grow between the cells of the root’s outer layer.  The second type is endomycorrhizae.  These fungi penetrate the root cells, forming highly branched structures called arbuscules.

“Instead of competing with other soil heterotrophs for decaying organic matter, the mycorrhizal fungi obtain sugars directly from the plant’s root cells.  This represents an energy cost to the plant, which may lose as much as 5 to 30% of its total photosynthate production to its mycorrhizal fungal symbiont.  In return, plants receive some extremely valuable benefits from the fungi.  The fungal hyphae grow out into the soil some 5 to 15 cm from the infected root, reaching farther and into smaller pores than could the plant’s own root hairs.  This extension of the plant root system increases its efficiency, providing perhaps 10 times as much absorptive surface as the root system of an uninfected plant.” (Brady and Weil et al. 2016)

Mycorrhizae assists in several critical roles in the health and growth of plants.  In addition to nutrient exchange they can aid in water absorption, acting as a sponge and increasing the root surface area.  Disease resistance by competition with other fungi for space and nutrients, producing antibiotics and altering the root epidermis.  They can even regulate the amount of heavy metals or salts that are taken into the plant. 

There is no doubt that mycorrhizae have a key role in the overall health, productivity and relationship between soil and plants.  This is why many want to increase the amount present in the soil.  There are already several strands of this native, beneficial fungi in most soils.  These native species will have a much better relationship with the vegetation planted in these soils.  There are many commercial mycorrhizae packages that can be purchased and added to medium, but it has been found ineffective and unnecessary.  “In controlled studies, when mycorrhizae products were added to the soil, follow up results found no trace of the actual mycorrhizal species that was introduced.” (Kunz et al. 2022) It is best to let the native species colonize the plants and not waste resources on commercial mycorrhizae applications. 

Brady, N. C., & Weil, R. R. (2016).  The Nature and Properties of Soils (13^th ed.). Pearson.

Colorado State University Extension. (2022, July 8). Mycorrhizae: Worth the Investment?

https://arapahoe.extension.colostate.edu/2022/07/08/mycorrhizae-worth-the-investment/

Soybean Cyst Nematode and Soil pH

When discussing Sudden Death Syndrome, or SDS, there are many avenues to navigate.  With soybean varieties broadening their landscape, and varieties becoming more accessible, it leaves growers with many questions.  What can I control, which variety is best for my region, and how do we prevent the spread; just to name a few. 

There are certain aspects of SDS we can control.  The largest being control of Soybean Cyst Nematode (SCN), a vector of SDS.  With any pest, an Integrated Pest Management, or IPM, approach is always the best option for long-term control and suppression.  For SCN many factors come to play when analyzing the spread, growth and reproduction but what can WE control. 

Planting populations, row width, cleaning equipment between fields, seed treatments and variety selection are all great starting points to reducing SCN populations.  For long term control, a study from the University of Wisconsin and Iowa State University sheds light on reducing numbers of SCN through proper fertility management.  This is not only something that growers can control, but a long-term solution. 

This table is copied directly from the article.  It clearly shows, from multi-year data, the reduction of SCN eggs/100 cc of soil as soil pH is reduced.  Some may be wondering, will lowering pH below 6.5 pH limit essential nutrients to the crop?  Yes, it can but everything must be kept within reason.  If SDS is your limiting factor for the highest yield, then it may be the best option to obtain a 6.5 pH rather than a 6.8 for reduced populations.  

The article, by Craig Crau and Nancy Kurtzweil, Department of Plant Pathology, University of Wisconsin, Madison and Gregory L. Tylka, Department of Plant Pathology, Iowa State University, Ames includes many other variables to the equation.  They also show yield differences between SCN-resistant and SCN-susceptible varieties, relationship between soil pH and final population density of SCN at harvest, and the severity of Brown Stem Rot at different pH levels using a selection of soybean varieties.  

For more information on how your soil pH effects Sudden Death Syndrome, Soybean Cyst Nematode and Brown Stem Rot please refer to the attached article.  https://www.mssoy.org/uploads/files/ph-and-scn.pdf

Tissue Testing and Spring Nitrogen Management for Wheat

Spring tissue sampling of winter wheat can be a very useful management tool. The timing of wheat sampling does not correspond to a specific growth stage though. The important factor when determining the appropriate time to sample wheat is that the wheat has broken dormancy and is actively growing again. Generally, wheat will be at a growth stage of Feekes 3 or 4 when this occurs. The appropriate method for collecting wheat samples at this stage is to collect 25 or more whole plants from ½ inch above the soil surface. One of the benefits of early season wheat sampling is to fine tune a “green-up” nitrogen application based on the nitrogen content of the plant at Feekes 5 (please visit the Purdue Extension News Release for more information). 

Soil testing for nitrate and ammonium can also help determine an appropriate rate of nitrogen to apply, especially in a situation where manure has been applied in the last several months. Samples should be collected to a depth of 12 inches with a minimum of 10 cores representing an area no larger than 20 acres. Once you receive your results, you can estimate the available nitrogen by adding the ppm of nitrate and ppm of ammonium and multiplying it by 4 to approximate how many pounds of nitrogen per acre are currently there. Keep in mind that nitrate and ammonium testing is a snapshot in time and can vary with the soil moisture and temperature. So, you should collect the sample as close to your planned application time as possible.

Once the plants reach Feekes 6 and beyond, indicated by stem elongation and jointing, only the most recent fully developed leaf should be sampled. The most recent fully developed leaf is the highest leaf on the plant with a fully developed collar. Once the plant begins heading (Feekes 10 and beyond), the flag leaf should be sampled. Generally, 40 to 50 leaves should be sampled at these growth stages.

Accurate plant tissue testing begins with proper sample collection and handling. Make sure to collect the proper plant part for the current growth stage of the crop and collect the proper number to make the sample. Always avoid soil contamination in your plant samples. Package samples in paper bags. If shipping is delayed, allow the sample to air dry, do not freeze. Never include roots with a plant sample. If you have any questions on proper plant tissue sampling, please contact the lab for assistance.

Maintaining Quality Data

So, who regulates agricultural lab quality? What federal government agency assures that an individual lab subscribes and adhere to a specific quality standard? Many of you reading might be surprised that there is no defined government regulatory agency for the agricultural laboratory industry, but this done not mean there are no rules or standards.

Some states require that if you perform agricultural analysis, that you be certified within that state. Wisconsin takes a step further and specifies the lab methods that must be followed as part of the state’s nutrient management regulation. These state certifications can be simply a permit process, other states verify that the soil test results fall within an acceptable range. For example, the state of Iowa specifies that “laboratories must achieve an average score of 80% or greater in the Iowa program of the NAPT soil Testing Proficiency Program” on 6 key lab analysis.

Within the agricultural laboratory industry, proficiency programs are the fundamental way to validate lab data. While these programs are voluntary, they are required for a lab to be certified in some states. The larger reason for a lab to participate and pass is to prove the lab produces quality data. Quality data is the terms of repeatable constancy over time.

Labs that participate in a soil testing proficiency program will receive a set of soil samples. These samples have been selected from around the country for specific parameters by the proficiency organization staff. A wide variety of soils are selected to thoroughly test the labs ability to produce soil test results that match the proficiency testing organizations results. Different standardized methods are used in different regions for the county, so the proficiency organization determines acceptable value range for all of the standardized lab methods. The proficiency program identifies an acceptable range of soil test results and then scores each laboratory as to how close the lab results match up with the proficiency organizations results. Often these test samples are sent to the participating labs quarterly. Labs must meet these quality levels for an extended period of time to earn and retain certification by a state or proficiency program.

A similar concept is used within the lab on a daily basis. The lab has two check soils that are prepared in relatively large quantities and in such a way to ensure that they are very uniform. These check soils are placed within the sample flow, one being known to the lab staff, and another as a "blind" check. The quality control department tracks the data generated from the these check soils to verify that data output is consistent over time. Approximately 10% of the soil samples analyzed at ALGL are check soil samples. 

In short, those labs that display current state and proficiency program certification are showing that they can reliably produce data that matches set quality guidelines.

For more information on the proficiency programs ALGL participates in go to: Certifications and Credentials | A&L Great Lakes and click on the links to learn more about the individual proficiency programs.

What Are Regulated Soil Samples?

Regulated soil sample is a term used at ALGL to identify a soil sample the requires special handling to avoid the spread of unwanted pests and diseases. These soil samples can originate inside or outside the continental US.

ALGL maintains a USDA Animal and Plant Health and Inspection Service (APHIS) permit to import soil and plant samples from outside the continental United States. These samples are allowed to flow through customs with an inspection, when accompanied by the correct permit. These permits are not to avoid import duties, rather they are part of a bigger effort to control the spread of pests and diseases. Regardless of trade relations with a country, these permits are required when shipping samples to our lab.

These permits are more than a piece of paper. They represent documented protocols as to how the lab will contain and dispose of these samples, in accordance with USDA/APHIS guidelines. These processes and procedures are created to avoid introduction of an undesirable pest or disease into the US.  Within the ALGL lab there are separate sample preparation facilities for these materials. These facilities and protocols are inspected by USDA/APHIS on a regular basis. These samples incur an additional handling fee.

While USDA-APHIS permit addresses the introduction of pests from outside the continental US, there are federal domestic soil quarantines within the continental US. These quarantine areas are designed for the same reason, to slow the spread of pests and diseases. The map below shows the areas of concern and is updated by USDA-APHIS regularly. The current map can be found at: https://www.aphis.usda.gov/plant_health/permits/organism/soil/downloads/Fed-SoilRegs.pdf

Here at ALGL we process samples from quarantine counties the same as soils from outside the continental US. These samples also incur an additional handling fee.

While shipping address on an inbound box help identify soils potentially from these areas. The origination of the soil sample may not align with a shipping address with the larger regions being covered by our customer today. We do ask if your soil samples originate from the areas marked in green or yellow that you indicate on your soil submission form that the soil originated from a quarantined county. If the soil samples originate from a county marked in orange, please contact the USDA before shipping the sample.

Comparing Grid and Zone Sampling for Site-Specific Nutrient Management

In modern agriculture, maximizing crop yield while minimizing input costs takes precedence.  Soil sampling techniques play a crucial role in achieving this balance by providing valuable insights into soil fertility and nutrient levels.  There are two primary sampling strategies when setting up a field: grid and zone sampling.  Each method has its benefits and drawbacks, and understanding the difference is essential for farmers to make informed decisions about their soil management practices.

Variability is a key factor in determining which sampling strategy to utilize.  It influences most in-field decisions including what, how and when to sample.  To understand what types of variables are present they can first be placed in two different categories. 

Temporal variability in agriculture fields refers to the fluctuations and changes that occur over time in various aspects such as crop yields, soil conditions, pest and disease outbreaks, and weather patterns.  These variations can be influenced by seasonal changes, climate variability, and agricultural practices.  Some in-season temporal changes could include nitrification or volatilization of applications, or plant nutrient availability due to seasonal changes.  A perfect example of this is fluctuating potassium levels in the soil profile.  Levels in corn acres are typically higher in spring samples, compared to fall, due to crop uptake.  The plant must wilt then decompose and return these nutrients to the soil causing fluctuations. 

Spatial variability refers to the differences in one location to the next.  These differences include soil properties, nutrient levels, moisture content and slope typically within the same field.  This variability can result from factors like soil type, topography, drainage patterns, and management practices.  Many times, these variations can be seen as surface features such as a low, waterlogged area to a high, sandy hill.  Other times they can be hidden within, or below the soil surface such as a previous lime pile site.  This variability would create a false representation of the grid area, or zone, by having increased calcium and/or magnesium levels.

Variability is unavoidable.  How we as farmers, applicators and agronomists understand/utilize this variability can have lasting impacts.  With modern technology, variability has never been more documented.  Often referred to as “big data”, it can be broken down into simple data sets.  These are commonly called data layers.  A data layer can be added, recorded, noted or submitted through an incredible number of avenues.  A few examples are planter ride quality, seeding population, hybrid placement, aerial imagery, nutrient placement, yield maps, even applicator name and contact information. 

The soil sample and nutrient maps are the most crucial data layers to sift through when making management decisions.  They have the most return on investment, when utilized properly, and can have lasting effects for years to come.  To fully encapsulate variability in a particular field, sampling strategy plays a large role.  The two textbook practices mentioned before are grid and zone sampling.

                Grid sampling is the most straightforward strategy in the soil realm. This type of sampling assumes the nutrient levels throughout the field are random.  Historically grid sampled fields have been fertilized in build up programs and masked the natural nutrient discrepancies across the working acreage.  Imagine a transparent checkerboard lying on top of a field.  These square, or grid, sizes typically range from 1-5 acres.  Within each square are, preferably, georeferenced sample points.  As mentioned above, variability is everywhere and repetitive sampling, in the same relative area, is the only way to get a respectable data layer. 

Grid sampling can offer these precise values to an operation through accurate representation and repetitive sampling but has its setbacks as well.  It is usually more time and labor intensive.  More samples will be taken from a field set up as grids.  This means it will also take much more time to do this job and that creates more costs.  However, in uniform fields the zones are much too large to get an accurate representation of an entire area and grid sizes are simply made larger.

Zone sampling is utilized in more stable environments.  Several of these areas are naturally occurring, and the spatial/temporal variability has been present for many years.  These sampling zones are created from these variabilities through many ways.  Yield monitors are a great indicator layer, when calibrated correctly, but only offer one piece to the puzzle.  To create proper zones, one must take all factors into consideration.  The natural variations of a field are recorded, and documented, using the yield monitor, aerial imagery, and soil tests (to name a few) to determine where zones differentiate.  These zones include waterlogged areas, slopes, and soil types.  Once zones are established, they can be used for much more than soil sampling.  Seeding/fertilizer rates, hybrid/variety type and even tillage/seeding depth can be adjusted according to zones.

All these factors can be isolated through other forms of data layers like scouting, soil sampling, aerial imagery etc. and made into its own zone.  This reduces the sampling costs by having larger sample areas but may have a higher start up cost due to the technology required and subscriptions used. 

Georeferenced sampling uses GPS, global positioning system, to mark a specific area.  This is important when sampling in a grid or making zones.  A common mistake is to place a sample location in an area where ag lime was piled before application.  If it is a referenced area, it is simple to find this location and see why certain outliers were present in a soil analysis report.  Another important reason to have georeferenced sampling is variability, as discussed above, is inevitable.  Nutrient variability is highly common, hence why frequent and repetitive sampling is required.

Grid sampling is still frequently used even though variability may move some points within a grid section.  To overcome this, some agronomist practice kriging.  Kriging is mostly used in grid soil sampling to predict values of unsampled locations based on spatial variability, such as slopes and hills, and nearby sampled locations.  If variable rate technology is not being used, it is wise to move points away from areas that will change application rates drastically. 

When deciding which sampling technique to use, all these factors must be taken into consideration.  If the field is a new addition to the farm, a grid style sampling technique is highly recommended, with a small grid size, to determine where variability exists.  If the results show drastic nutrient levels, an even smaller grid size is required at the next sampling date to determine what is needed, or not needed, and where. 

While grid sampling provides precise data for targeted nutrient applications, it can require more time and costs.  On the other hand, zone sampling offers a more practical and cost-effective solution for large scale operations but may sacrifice precision.  The choice between grid and zone sampling should be based on factors such as field size, budget, goals, and the level of detail required for effective soil management practices.  By selecting the most appropriate soil sampling method, farmers can optimize nutrient use efficiency, enhance crop productivity, and sustainably manage their soils.

Your ALGL sales agronomist can help determine with method is right for you.