Liqui-Grow

Is an Adjuvant Worth the Money?

As you look over your chemical prepay, did you include an adjuvant? Facts are, adjuvants are worth the money, and here’s why.

Adjuvants have a number of jobs. They help condition water, stop evaporation, even out spread patterns, and above all, adjuvants make sure those expensive herbicides get into the weeds to stop growth.

Adjuvants are the difference between the herbicide being lost to rolling off the leaf surface and getting down into the leaf. In order for a herbicide to be effective, it has to get through the outer layers of the leaf and into the plant cells. This means it has to get through the outer waxy layer (cuticle) and the cell wall, where it can reach its specific site of action. This is the primary reason why adjuvants pay for themselves. It's harder to get a herbicide into a plant than you might think!

Barriers to Entering the Leaf

The leaf's outer layer, called the cuticle, is made of wax. It prevents the plant from drying out and protects the leaves from excessive UV rays, so it’s naturally tough to penetrate, making it difficult for herbicides to get through. There are 2 main paths through this cuticle.

Every plant species differs in cuticular structure, and environmental conditions can influence how this layer changes daily. For example if it gets hot, the waxy cuticle layer can become thicker, protecting the leaf moisture, and that also makes it harder for herbicides to enter.

Think of a plant leaf as having layers: some parts mix well with water, and others with oil. For a herbicide to work, it has to move through all those layers to reach the inside of the plant cell. Some herbicides, like glyphosate, mix better with water than with oil. That can make it harder for them to move through the waxy (oily) outer layer of the leaf.

This is where an adjuvant helps.

An adjuvant acts like a “bridge.” It helps the herbicide work with both water‑loving and oil‑loving parts of the leaf. Because of that, the herbicide can move through the waxy cuticle, penetrate the cell wall, and reach the inside of the plant, where it can do its job.

In simple terms:
An adjuvant helps the herbicide penetrate the plant more easily, allowing it to kill the weed.

Adjuvant Jobs

Water Conditioners are adjuvants that do just that: they condition hard water so that herbicides don’t get tied up by cations. Water conditioners prevent the herbicides from being tied up, so they don’t just sit on the leaf surface; allowing the herbicide to actually do the job they were meant to do.

An adjuvant containing “sticker/spreader” components (wetting agents) function just as the name suggests. Sticker/spreaders, spread the herbicide across the leaf surface. Similar to how rain droplets bead off and keep them on the leaf until they are absorbed. Labels often mention “humectancy,” which indicates the enhanced ability to retain water and slow droplet evaporation before entering the leaf. This aids in overcoming the waxy and hairy surfaces of many weed species, preventing herbicide droplets from 'shedding' immediately, as they would without an adjuvant. In other words, the droplets stay wet a little longer and allow the herbicide to get into the leaf surface.

Crop oil Concentrates are another adjuvant used in spray applications. They help soften the waxy layer, allowing easier entry through it for the herbicide. This is why crop oils “heat up” a mix and can cause crop damage; the implications of not controlling the weeds or ending up with resistant weeds are oftentimes, much worse than the visual crop damage that the crop should be able to quickly outgrow. Crop oils also provide better leaf coverage and keep the leaf wetter, longer than water alone. Crop oils can be more detailed. Follow along to hear more.

Different growing conditions require different crop oils for the best herbicide performance. Drought conditions create tougher weed control challenges. Plants, both weeds and crops, under drought stress produce a thicker cuticle, which is a natural defense response. They are trying to save water and overcome drought stress. Using an MSO (methylated seed oil) has the advantage over a traditional COC (crop oil concentrate) by helping the herbicide enter the plant faster, even as the plant works to make entry through the cuticle more difficult.

When spray conditions are good, we might only need a NIS (non-ionic surfactant). An NIS primarily helps improve herbicide leaf coverage, by reducing the surface tension of the water allowing it to spread out further on the leaf allowing more area for penetration into the leaf. They also typically have ingredients that perform the “sticker/spreader” role and keep the droplet on the leaf from being too quickly evaporated or rewetted by dew or other moisture. If you’re not sure which COC is best for your operation, ask a Liqui-Grow Agronomy Field Advisor!

What adjuvant to use under what growing conditions

Environmental Conditions that reduce herbicide uptake:

Low Humidity/High Evaporation (NIS/Humectant)

High Humidity/Heavy Dews (Spreader/Sticker)
Hot, Dry Weather (COC, MSO)
Cool, Wet Weather (NIS)
Windy Conditions (Drift Reduction/Deposition Aid)
Hard Water used as a carrier (NIS/AMS water conditioner)

Plant Physiology that reduces herbicide uptake:

Structure of Cuticle
Thickness of the Cuticle
Hair on leaf surface (can suspend droplets so they evaporate before touching the leaf)
pH of the leaf surface

Drift/Deposition Adjuvants

Some adjuvants can reduce drift and also penetrate the canopy. These products can be added to maintain droplet size and help reduce evaporation. These same products may be able to penetrate the canopy and increase leaf coverage, ensuring better herbicide weed control. These products are also very important when utilizing in-season applications or fungicide applications.

Tank Mixes and Labels

When you’re deciding which adjuvant to use, the tank‑mix guide and the herbicide label are the best places to start. Herbicide labels will tell you which adjuvants work best with that product, and sometimes they even give different recommendations depending on the weather or field conditions.

If you’re mixing several products in the same tank, remember: the adjuvant you choose can affect how the other products behave. That’s why you always need to think about how everything in the tank will interact.

It’s also important to follow the right mixing order. A water conditioner should always be added to the water first. Oils like MSO or COC, or drift‑control products, usually go in last. Doing a quick jar test is a great way to see herbicide compatibility and correct mixing order. Always check the label first.

And above all, follow the label. If you’re unsure about anything, reach out to a Liqui‑Grow Agronomy Field Advisor. They can help you make the right call.

Summary

By now, you’ve probably noticed that adjuvants are almost as important as the herbicide itself. They help the herbicide do its intended job, which means you get better weed control and help slow down the chances of weeds becoming resistant in the future.

Here’s something important: using an adjuvant doesn’t mean you can lower the herbicide rate. The adjuvant helps the herbicide enter the plant by overcoming barriers that would normally block it, such as the waxy leaf surface or tough weather conditions. Once the herbicide gets inside the plant, the rate you applied matters a lot. That’s what determines whether the herbicide can reach and shut down the plant’s specific target site.

So don’t cut herbicide rates, thinking the adjuvant will make up for it. Its job is to help the herbicide get where it needs to go, not replace the amount of herbicide you need.

Liqui-Grow – Recipient of Agribusiness Impact Award

January 27, 2026 AAI Agribusiness Award Awards Education History Impact Legacy Stewardship

The Agribusiness Impact Award recognizes individuals and businesses who have made a lasting impression and impact on Iowa's agriculture.

Thank you to the Agribusiness Association of Iowa for choosing us at Liqui-Grow to receive this award. We are honored and proud to accept the Agribusiness Impact Award and we’d also like to congratulate the other inaugural honorees:

Steve Sukup, Sukup Manufacturing
Dave Tierney, Bayer CropScience (retired)

It is an honor to stand alongside of these individuals who have made significant contributions to Iowa agriculture and to be recognized with leaders who have helped shaped the industry. Liqui-Grow is committed to serve Iowa agriculture, and communities today and every day.

Weed Control Lessons from 2025

October 10, 2025 giant ragweed herbicide ragweed waterhemp weed weed control

There were several challenges for soybean weed control in 2025, and as the combine rolls, you can still see those weed escapes as you harvest across the field.

Weather

The weather was a main factor throughout the growing season. Relentless rains and storms in 2025 prevented timely herbicide applications. Rains and wet soils also provided a wider window for weed seed germination, especially waterhemp. Combine those two factors with lower GDU’s heading into June and the use of 30” rows, which caused slower canopy growth, and we had lots of weed issues.

Rather than offering broad recommendations, let's focus on the specifics for giant ragweed and waterhemp, including their life cycles and control strategies to help you protect your soybean yields in 2026.

Giant Ragweed Characteristics

Giant Ragweed's biggest advantages are:

Early-season emergence
Fast growth rate
Season-long adaptability

Ragweed is like the big guy at the party that can use its size for intimidation and dominance. It can grow up to 17 feet tall and typically will grow 1-5 feet above the crop canopy. Just one giant ragweed plant per 110 square feet can reduce soybean yields by 50% if left uncontrolled.

Both weed species have impressive growth habits and will outgrow soybeans quickly. Farmers cannot afford to get behind and try to catch up. The abilities of these weed species to emerge throughout the season require farmers to have:

Well-timed herbicide applications
Multiple modes of action
Residual herbicides
Fast canopy closure

Shade out the Rows

Canopy closure is critical since these weeds are very sensitive to shading. Waterhemp, in particular, prefers unfiltered sunlight for germination and growth, so accelerating canopy closure is necessary. Two management strategies to help with fast canopy closure are:

Early planting
Narrow row soybeans. - A 15” row will canopy about 25 days sooner than a 30” row.

In Iowa, narrow rows can offer a 5-10% yield advantage, which is a great benefit above and beyond weed control. If switching to narrow rows, consult your Agronomy Field Advisor on a variety with a good disease package and low lodging scores for maximum success. If you are in wide rows, really think twice about cutting a pre-emergent herbicide pass. The longer the canopy is open, the longer you need to keep the soil weed-free. If you’re sticking with a two-pass post system, timing is everything. And if your budget allows, consider including a residual product to add some residual holding power.

Tillage

Tillage has long been used as a method for weed control, based on the idea that burying weed seeds reduces their chances of germination. While deep tillage can be highly effective, it’s not always the best practice for every farmer. If deep tillage is used, it’s recommended to avoid further tillage for 4 to 5 years to keep the buried seeds from resurfacing and germinating. However, giant ragweed presents a unique challenge since it can germinate from depths of up to 4 inches below the soil surface, making most modern tillage practices ineffective against it. Additionally, spring tillage tends to stimulate germination of both giant ragweed and waterhemp, offering little benefit in terms of long-term control.

Herbicide Use

Lastly, chemical control is a critical piece of the puzzle. Over the past couple of years, tighter profit margins on soybeans have led many farmers to think about skipping residual or pre-emergence herbicides. 2025 was not the kind of year to skip pre-emergent herbicides because excessive rain made timely applications nearly impossible for those trying to implement a two-pass post-emergence plan.

Products like glufosinate and 2,4-D can be effective against waterhemp and giant ragweed when the weeds are less than 3” to 6” tall. Utilizing a pre-emerge helps slow them down and gives you time to get back into the field, in case the weather isn’t cooperating. If a pre isn’t an option, use your spring tillage pass strategically. Minimize the time between tillage and planting, and follow up quickly with your first post-emerge spray. Horizontal tillage tools (like field cultivators) generally offer better weed control than vertical tillage.

One last, but essential point is that these weeds are becoming increasingly intelligent. To give you a sense of just how tough these weeds really are, waterhemp and giant ragweed both cross-pollinate, which helps them overcome these herbicides and creates resistance, such as ALS-resistant giant ragweed. These weeds can also regrow from each leaf, known as the leaf axis, making it even more challenging to maintain full control. To fight back, use a pre-emergence herbicide with PPO inhibitors (Group 14) to help manage these populations. Giant ragweed has developed glyphosate resistance through two different mechanisms: a “non-rapid response” type that slowly turns chlorotic before recovering, and a “rapid response” type that shows necrosis on mature leaves but also bounces back.

Sidedress Nitrogen

May 5, 2025 Corn in-furrow Nitrogen Nutrient sidedress y-drops

4 Quarters to the Game!

If you’re playing a game of basketball, you know you’ll need to bring hydration with you so you can replenish your body throughout the game to keep you going. The crop in our field is no different. We can lay down nutrients at the beginning of the season and hope the crop is fed for the whole season, or plan some in-season applications. With the progression of equipment and application, adding additional nutrient applications throughout the year has become standard and an accepted practice. So, when should you concentrate most on additional applications?

V4-V5 Corn Application

Best practices would say the corn will reach V4 about 22-24 days after emergence, based on GDU’s. By knowing this information, you can better plan that sidedress trip across the field. When planning to sidedress corn at V4, it allows the nitrogen to be there for rapid uptake. It also allows extra time for weather that can interrupt and delay our plans. Once we reach V8, corn absorbs between 4 and 8 lbs of nitrogen per day as the plant grows from about 12 inches to 12 feet tall. By tassel, it has taken up approximately 60% of what it needs for the season. This early application timeframe is ideal to ensure nitrogen availability during peak uptake demand.

Sidedress application is one of the best ways to utilize your dollar spent on nitrogen fertilizer. Since placement and timing are big factors in how well your nitrogen fertilizer is taken up, using Y-drops at V3-V4 would be ideal to lay nitrogen near the rootzone and right before the period of rapid uptake. Corn roots remain relatively small at V3 - V4 and often cannot reach the middle of the row. Sidedressing in the middle of the row (during V3-V4) is not as ideal, but still a better option than placing all of the fertilizer up front.

Does sidedressing nitrogen always lead to higher yields? That depends; sidedressing nitrogen allows for better nutrient placement and utilization. The soils aren’t as warm early in the season, which means they haven’t mineralized many nutrients, so having some nitrogen present at V3-V4 keeps the crop fed. If we experience heavy rain events and nitrogen is leached or denitrified, there is a strong likelihood that sidedress nitrogen will contribute to yield increases.

Liquid vs. Urea

There are a few cons to using urea in-season. To effectively use urea during the growing season, it should be properly incorporated. This can be done with rainfall; a minimum of 0.5 inches is required to accomplish the incorporation and prevent loss of urea. Urea loss is typically lost to the atmosphere. Urea can also be difficult to spread evenly across tall corn. Keep in mind that tall corn can act as a funnel or wall, blocking the dispersal rate of urea applied over the top of the plants. Urea particles typically vary in size, which leads to uneven spread patterns as they "fling" at different rates. UAN, on the other hand, is only 50% urea and is about half as susceptible to ammonia volatilization compared to urea. UAN can be subsurface injected, eliminating volatilization chances, or surface banded, which still significantly reduces volatilization. Sidedress applications of UAN are uniform across the acres and reduce the yellow streaking often associated with top-dressing urea. Of course, using a nitrogen stabilizer at any UAN application should be discussed with your Agronomy Field Advisor.

Late Season Application - We Can Do It. Is Late Season the Right Time?

The development of “ highboys” and Y-drops has allowed for nitrogen applications later into the growing season, which is ideal for workload and logistics in many cases. But, is that better for the corn crop? Like everything in agronomy, “it depends” because, in ag, our weather is never the same from one year to the next. We also know that different genetics utilize nitrogen differently. Two advantages of late-season timing are:

If your corn crop appears to be strong, you might consider adding a little extra to meet the increased demand.
If you fear nitrogen loss because of heavy rains in the early season, later-season applications allow for good placement at a time when moisture can be limited.

A quick rule of thumb is corn takes up 60% of its nitrogen needs by tassel, and 40% during reproduction. During the period of rapid vegetative growth, corn requires ~4-8 lbs/N/day to keep on pace, as stated earlier. Nitrogen primarily enters the roots through mass flow. Mass flow occurs when water entering the roots carries the nitrogen with it, ultimately hitching a free ride. If the forecast shows very little rainfall chances, it does not make much sense to apply extra nitrogen knowing we need mass flow of water for root uptake. This should be a greater consideration the later we progress in the season. Y-drops, like stated earlier, keep the nitrogen closer to the roots, but they also allow the dew and what little rainfall that does happen to carry it down to the rootzone where it can be used. Because of this advancement, you can now purchase sidedress applicators with coulters and y-drop attachments.

Conclusion

Today’s hybrids utilize nitrogen much more efficiently than their ancestors, and produce more bushels with the same amount of nitrogen, or less in some cases. Make sure you are feeding corn the way it can best make bushels for you!

If you have an interest in adding a sidedress application of nitrogen to your corn crop this season, contact your local Agronomy Field Advisor at Liqui-Grow! We offer different applications and timing to meet your crops’ needs and yield goals.

IDC in Soybeans

May 5, 2025 deficiency IDC Iron NO₃⁻planting soybean

Yellowing and Dark Green Spots in Soybean Fields

If you are driving through north central Iowa on an early June day, you may notice soybeans yellowing in interesting patterns. You may also notice dark green “tire tracks” that run up and down soybean fields due to previous sprayer field passes. These are often the first signs of Iron Deficiency Chlorosis (IDC). IDC is an ongoing challenge for growers in this region of the state. It is due to inherent soil properties that are not easily changed, such as calcareous topsoil, which results from a calcareous subsoil that was formed when the glaciers came across millions of years ago. Basically, not something we can go back and change.

What is IDC?

Iron Deficiency Chlorosis is a phenomenon caused by a lack of available form of iron to the soybean plant. Key words, “available form.” Soil test reports are a great way to start with a baseline for plant available nutrients. In this high IDC area, iron, (Fe) often times, has high levels across wide areas. You would think it’s most available then, and we have plenty of it. Soil test results may read iron is available to soybeans, but the combination of iron and pH need to be assessed in order to conclude you potentially have IDC issues.

So why does this happen? As you see in the pH chart, iron availability to plants, reduces at High pH soils. Soybeans can only use iron in the form of Feᐩ². In this part of the world, it’s more common to find iron in the form of Feᐩ³. Now, soybeans do have the ability through their roots to excrete acid and reducing agents to move Fe into the available form of Feᐩ². Soybean varieties that tolerate IDC do this better than varieties that are more susceptible. To learn more about IDC, ask one of our Agronomy Field Advisors!

These are all great clues to solving your problem fields!

The following soil conditions should help you figure out if IDC could be the root of problems in your soybean fields:

pH greater than 7.4 (Don’t use only pH. What does that mean? Keep reading!)
Excessive Free Lime
EC (soluble salts) greater than one mmhos/cm. In other words, look for areas that pond in fields.

Other not-so-scientific factors are:

High soil moisture
Excess nitrate in the surface soil - look for dark green wheel tracks across fields
Certain soil series that are typically calcareous in the topsoil, including Harps, Canisteo, Okoboji, and sometimes the Nicollet-Webster series

The pH test is often sufficient for soil tests to determine whether iron and other nutrients are available. If you suspect IDC is an issue in a particular field, we suggest adding the Excessive Free Lime and the EC (soluble salts) tests, which can confirm IDC suspicions.

What to do about IDC?

1. Buy the right soybean for this type of field.

The best and easiest option is to start with a soybean that is bred to be planted in high IDC areas. These varieties won’t cost more money, just time selecting varieties and placing them on the right acres. Agronomy Field Advisors at Liqui-Grow can help pick out the right bean for the right acre! Soybeans naturally acidify the rhizosphere (area immediately surrounding the roots), which reduces iron into the Feᐩ² form, making it available for plants to use. However, a soybean that has a better IDC rating is more efficient at this process, meaning those varieties will oftentimes thrive better in heavy IDC fields compared to soybeans that are not as tolerant to IDC.

2. Don’t apply iron to your soil!

As we just mentioned, there is plenty of iron in the soil, it's just not in the right form. Adding additional iron is not practical, oftentimes, it will change forms because of the soil environment and become unavailable. If you can’t help yourself, then it’s best to use an iron chelate through an in-furrow starter on your planter. Use the iron chelate form that is most available at your pH level; anything above 7.4 is typically EDDHA, which is the strongest of the chelates, and is able to keep iron in a plant-available form when pH is above 9.0.

3. Reduce the amount of nitrate available in the surface soil.

Nitrate carryover from a corn crop at the soil surface plays a large role in how bad iron deficiency chlorosis symptoms are. Visually, scientists attribute the “green wheel tracks” to the compaction caused by wheels, which then reduces oxygen availability, resulting in the denitrification of the nitrate. The bottom line is that less nitrate means less IDC. A way to alleviate excess nitrates could be the use of cover crops. Any cover crop such as rye, wheat, triticale, etc., will uptake a lot of surface nitrate and reduce the severity of symptoms.

**Bonus - Getting into the weeds:
Soybeans prefer to take up nitrate, NO₃⁻ (hence why nodulation is reduced under higher nitrate levels), and when the plant takes up NO₃⁻ , soybeans have to balance the charge. They release bicarbonate HCO₃⁻ ions, which buffer the acidification effect from the roots. The acidification effect from the roots is what makes the iron more available. So, in other words, it's a win/lose situation. They are enjoying the free nitrogen, but they can’t utilize it because they can’t take up iron. Iron is essential for the production of chlorophyll, which is what makes the plant green and drives more growth.

4. Tile!

A great strategy to limit iron deficiency chlorosis is to reduce the amount of water standing in the field and add subsurface drainage in these areas. Soils that hold water are soils that accumulate bicarbonates. Bicarbonates will buffer the acidification effect from the soybean roots. This is the same thing that happens in the case of excess nitrate. Reducing excess water reduces bicarbonates. An Agronomy Field Advisor can have the Excess Lime Test completed to measure the bicarbonate levels.

5. Plant higher populations in those parts of the field

If your planter is capable of variable rate prescriptions, planting different populations in high IDC areas can be a lot easier than a traditional planter. It is still possible for a traditional planter to plant different populations though. The idea behind increasing populations is to pile the roots on top of each other and overwhelm the rhizosphere with acidification from roots. Typically, you need to push populations close to 200,000 or higher in 30” rows to see the impact from it. When it comes to extra seed, there is a cost, so calculating what your lost yield is worth before adding population is beneficial.

How to Make Variable Rate Seeding Recommendations for Corn and Soybeans

April 1, 2025 Corn determinate flex planting rate seeding soybean variable

Knowledge is king! So, knowing what type of corn hybrid is planted in the field is the first step in deciding on a VRS rec. Another piece of information for VRS decision-making is knowing each field's soil type and yield potential. Some of our modern hybrids have a determinate ear style and will benefit from higher seeding on heavier ground. However, these are also the hybrids you can’t drop too low on populations. Why not? See the table to the right for different ear type explanations!

The majority of the hybrids planted today are semi-flex. Semi-flex hybrids allow flexibility in more challenging soils such as low-yield environments, low CEC, and low organic matter content. In tougher fields, we can lower seeding rates, and use semi-flex hybrids on VRS seeding recs. This allows hybrids to be able to conserve moisture by giving them more space between roots. For example, think of hot dry conditions, and light sandy soils, do you really want to overcrowd that planting environment?

Determinate (Fixed)	The corn plant will typically produce the same size (girth/length) ear no matter what population is planted. These hybrids excel in good to excellent soils/fertility and narrow rows when pushed to higher populations. In general, these hybrids flex very little in girth and length but may flex some in kernel depth.
Semi-Flex/ Semi-Determinate	The corn plant will slightly adjust in ear girth and/or length depending on the population planted. These hybrids are the best of both worlds because they won’t give up as much as a flex hybrid in really tough environments, but they can flex some if they have ample water/nutrients. In general, these hybrids flex in at least 2 out of 3 directions.
Flex	The corn plant will flex a lot and have more length and/or girth at lower populations and when they have ample water/nutrients. They don’t like to be crowded, especially in lower moisture environments. In general, these hybrids can flex in all three directions.
Key: Girth is the rows of kernels around an ear of corn. They will always be in sets of two. Length is the number of kernels down an ear of corn. Kernel depth is how long an individual kernel is from the cob to the tip of the kernel.

Variable rate seeding can help reduce seeding costs on low-return acres and save on your input cost. This is just one example of how Liqui-Grow can evaluate your hybrids and fields to determine what variable rate seeding goals and recs are best for you!

Keep in mind that universities, industry experts and top-yield corn farmers alike stress the importance of placing the right genetics on each field. Liqui-Grow makes placement and population a priority when we build a variable rate seeding recommendation to help you get the most out of those genetics.

By using Liqui-Grow to create your variable rate seeding recommendations, we can couple that with a variable rate nitrogen management recommendation as well. This will allow the correct amount of nitrogen to be applied to the correct population. In other words, we can make sure that you have the right amount of “food” for the party!

Soybeans - here’s the secret…there is no secret.

If you are interested in variable rate seeding for soybean planting, there are a few situations worth trying higher seeding rates. First is lighter, sandy areas. Second would be high pH soils which are oftentimes associated with IDC or iron deficiency chlorosis. Such soil types would be, but not limited to, Harps/Canisteo/Okoboji.

The best strategy would be to evaluate how much yield loss these two issues are potentially causing. If it is a severe issue (greater than 50% yield loss), then it will likely respond to some management techniques, like variable rate seeding. If you only see a slight yield reduction or only on years when the growing conditions are “just right,” then it’s likely not worth it as soybeans can adapt to changing environmental conditions. If that’s all you want to know, call your Agronomy Field Advisor, and get creating those variable rate seeding recommendations! Otherwise, read on!

Soybeans have a large ability to adapt to changing environments and, therefore, can be unresponsive to many management tactics, including variable rate seeding. Under the right conditions, especially if a field consistently shows troubling soybean yields due to any of these factors, it may be worth trying VRS.

Most often, soybeans planted on soils that are lighter or sandier never fully canopy. Anytime you can close the row and reduce evapotranspiration loss, the soybeans stand a better chance of putting on more pods and seeds. In other words, the more rows you have closed, the more yield you can grow! Closing the row also helps with weed control. In these situations, in sandy soil spots, variable rate seeding can push populations up, which means the soybeans have more “inter-row” competition and will force the beans to grow taller, thus having a better chance of closing the rows.

Here's Why:

Higher populations crowd the plants and force roots to be closer; roots may even overlap. Those roots change the environment they live in and allow iron to be taken up by the plant and utilized. There are a lot more details to this; we’ll have a blog coming shortly on the IDC topic! - If you’d like to be notified about our IDC Blog post - sign up for our newsletter!

In many cases, growers try to use a soil type map to create variable rate seeding soybean recommendations, however, it would be better practice to use pH from a grid soil sample (preferably 2.5 acres) to establish those areas where IDC are the worst. We can always overlay soil type however those maps were created in the 1960s and are not intended for the accuracy we are trying to use with GPS applications today.

Soybean yield data is not nearly as consistent year to year as corn yield data and doesn’t reveal soil changes as well as corn yield data does. Take the iron deficiency chlorosis problem for instance, it doesn’t always show up in the exact same spot depending on several environmental factors.

Essentially, variable rate seeding soybeans is challenging, but if you have a severe yield-limiting issue like we just discussed, there is a better chance that variable rate seeding could have an impact on your soybean yields. Your local Liqui-Grow Agronomy Field Advisor would be happy to help you figure out if that yield-limiting issue is worth a variable rate soybean recommendation or if another solution is more beneficial.

How Much Do I Need to Spend on Starter Fertilizer?

March 17, 2025March 18, 2025 acid liquid ortho-phosphate phosphate poly-phosphate potassium

When deciding on what phosphorus source is best for your crop, companies may refer to the type of acid used in their phosphorus starter. You’ll likely hear one of these terms:

Black Acid - it’s black because there is carbon in it.
Green Acid - which is green or sometimes translucent, has some carbon in it.
White Acid - which has been conditioned to remove the carbon, has no carbon. The conditioning typically will mean the product has been handled more and therefore often costs more. White acid does typically have a higher ratio of ortho to poly phosphates.

Now, how does this affect starter fertilizers?

These different types of acid have different ratios of ortho-phosphates or poly-phosphates. Ortho-phosphates are 100% plant available, as they are applied at planting. Which you would think, “Great! I want that available right away to the plant.” Plant have to take up ortho-phosphates. Therefore farmers think they need ortho-phosphates.

Poly-phosphates have to convert in order to be plant available. Here’s where farmers get hung up, and miss the cost-savings opportunity.

A high percentage of poly-phosphates in starter fertilizers convert to ortho-phosphate within just two days after application. 10-34-0, for example, is roughly 50% ortho-phosphate and 50% poly when applied to the soil. When 10-34-0 is applied to the soil, a chemical reaction occurs and 50% of the poly-phosphates convert to ortho in three or four days, and the rest will convert within two weeks.

So by the time the corn kernel germinates, the majority of the poly-phosphates have converted to ortho, ready for corn uptake.

Field Study

Dr. Jake Vossenkemper completed trial work locally to prove this and has provided a 5-site year summary below.

for In-Furrow Seed Safe Starter Fertilizers – 5 Site-Year Summary

What Dr. Jake found was, this quick conversion from poly to ortho-phosphate suggests expensive “high” ortho starter fertilizers are not likely to result in increased corn yields compared to conventional poly-phosphate starters.

On-farm field studies conducted near Traer, IA and Walnut, IL from the 2016 to 2018 growing season found no statistical difference (Pr > 0.05) in corn yield between conventional and high ortho-phosphate starters.

High ortho starters cost more per/ac than conventional poly-phosphate starters, but do not increase corn grain yields.

Given poly-phosphates are not immediately plant available and ortho-phosphates are immediately plant available, this gives the promoters of “high” ortho-phosphate starters ample opportunity to muddy the waters. Nevertheless, the facts are, poly-phosphates are rather rapidly hydrolyzed (converted to) into ortho-phosphates once applied to soils, and this hydrolysis process generally takes just 48 hrs or so to complete.

How the Field Trial Was Conducted

In these field trials we used two starters applied in-furrow at 6 gal/ac. Each starter had a NPK nutrient analysis of 6-24-6. The only difference between these two starters was the ratio of ortho to poly-phosphates. One of these starters contained 80% ortho-phosphate and the other contained just 50% ortho-phosphate. With the remainder of the phosphorous source in each of these two starters being poly-phosphate. At the Traer, IA locations the plots were planted with a 24-row planter (picture 1) and were nearly 2400ft long. At the walnut, IL locations the research was conducted using small plot techniques, plot dimensions there were 10 ft wide by 30 ft long. At both Traer, IA and Walnut, IL in each of the 3 growing season the experimental design used was a simple randomized complete block with 4 or 5 replications.

Field Trial Results

Averaged over the 5 site-years there was only about 1.5 bu/ac yield difference separating the high ortho and conventional poly-phosphate starter (figure 1). Moreover, this small yield difference was not statistically significant (Pr > 0.05). In addition to finding no differences in grain yield between these two starters, the high ortho starter cost about $0.50 more per/gal (so $3/ac difference in price at a 6 gal/ac rate) than the lower ortho starters. So the more expensive high ortho starter clearly did not “pay” its way in our multi-location field trials (figure 2). Lastly, our observations in these studies agree with previously published university findings (Frazen and Gerwing. 1997).

References

Franzen D. and J. Gerwing. 2007. Effectiveness of using low rates of plant nutrients. North Central regional research publication No. 341. http://www.extension.umn.edu/agriculture/nutrient-management/fertilizer-management/docs/Feb-97-1.pdf (accessed 8 of Sept 2015).

The Best Option to Kill Cereal Rye Cover Crops in the Spring

February 24, 2025 AMS Cereal Rye Cover crops dicamba hppd sharpen

Why this difference?

The weather and the air temperature play a big part in killing cereal rye. If we don’t have good growing weather for plants to grow, we won’t get an effective kill. Plants need to be growing in order to take up the chemistry and start working. To get a good effective kill, glyphosate needs 3 days of air temperatures in the mid 50’s for highs and not below 40 degrees F for evening lows. These temperatures are required for active growth, which enables the glyphosate to get absorbed and for good movement throughout the plant for an effective kill. So be looking for that 3 day window come early this spring. I recommend the higher 1.5 lb a.e. rate if you even suspect temperatures won't be ideal during application. Not killing cereal rye can have significant impacts on cash crop yields so increasing the rate of glyphosate is a relatively cheap alternative to manage risk. As they say in the industry, a dead weed is a good weed!

If you’re looking for options to enhance broadleaf control in your burndown program, adding Sharpen® (saflufenacil), 2,4-D, or Dicamba will not antagonize the glyphosate, but HPPD inhibitors, atrazine, and metribuzin will.

Don’t forget appropriate adjuvants

For glyphosate, NIS is optional, depending on situational instances. Given the possibility of challenging weather during early spring, we recommend NIS at 0.25% V/V. Finally, the AMS must be included. The AMS will:

reduce any antagonizing effects of hard water
increase effectiveness in challenging environmental conditions
reduce the antagonistic effects from any other thank mix partners

You should be able to reach all of these goals by using a minimum of 10 lbs of AMS per 100 gallons. It’s always important to completely dissolve the AMS prior to adding glyphosate. Liqui-Grow’s Agronomy Field Advisors have experience in terminating cover crops, so be sure to reach out with any questions!

You Keep Hearing the Word Biologicals in Agriculture

February 13, 2025February 20, 2025 amino acid biological biologicals Corn inoculant MicroAZ microbes soybean

First off, why do we hear so much about biologicals?

We know technology builds on technology, and as we advance, computing power becomes more reasonable in cost, time, and effort. Today's computing power can manipulate and understand biologicals much better than even 10 years ago. This makes biological products more consistent in use and output. Another factor driving the R&D and use of biological products is the overall public concern for environmental stewardship. Basically, people care about and voice their opinions more on how the earth is being cared for.

Biologicals - what are they and what can they do?

“Biological” is an umbrella term for something that is made from a living thing or organism. There are three biological categories: biostimulants, biofertilizers, and biopesticides. We are primarily interested in biostimulants and biofertilizers.

Biostimulants - help crops grow, make them “feel good,” and mitigate stresses. They aren’t always a live product, some of them are derived from a live product.
Biofertilizers - these products often enhance plants' nutrient availability, uptake, and usage of nutrients.

You might think, ” Yeah Right! How can a jug of “stuff” magically help?” Biologicals have been around agriculture for many years, but as previously stated, affordable technology made it available to really study and understand what material can do and is capable of doing for plants.

You probably wonder how a biological product will know it's supposed to help roots grow. It’s sort of like roots and high fertilizer concentration. Generally, roots will grow well in soil with a high concentration of fertilizer and nutrients. The roots like to be around high concentrations of nutrients. Microbes, which are a type of biological, act the same as soil nutrients. When roots are near areas with high concentration of microbes living in the soil, they know that’s a good place to live, and they want to grow there as well. Microbes can sense the sugar that roots exert and feed on that sugar to live. So, the short story is, “You scratch my back, I'll scratch yours.”

Here is where we get into the weeds….Stick with us, it’ll be worth it.

Amino Acid based products are also a type of biological, or, as Dr. Jake likes to call them, “non-traditional products.” This is because amino acid based products are derived from a biological organism.

There are 21 essential amino acids that build proteins. Proteins, ultimately, build yield. Whereas humans can eat amino acids and build protein, plants cannot. Plants need to produce their own amino acids; building these amino acids takes energy. Plants make these amino acids through 21 different molecular pathways. If plants are required to use their energy to make their own amino acids to build protein which builds yield (are you seeing a pattern here? Can you hear the song, “and the green grass grows all around all around, and the green grass grows all around…”) **Back to the story of plants building their own protein.* If and when stress happens during the growing season, it slows down amino acid production and plants might not make proteins or become less efficient when building proteins, thus creating yield drag or loss of yield.

Now, plants have the ability to store amino acids, so when you apply an amino acid to plants or the field, plants can store it until they need it. So typically, we don’t have to be super exact in timing because plants can “save it for a rainy day”.

You might wonder, how do they get into the plant? These amino acid based products are charged (think chemistry charges of negative and positive) in a way they can pass through the leaf tissue or go up directly through roots. If plants are provided amino acids through the leaves or roots, they will take them instead of exerting energy to build them. Basically, a free lunch.

The When and Why of Biologicals

Biological products can be used throughout the growing season for different reasons. It's important to determine why you need a biological and what you want the goal to be. Some major benefits of biological products in-season can help with:

N-fixation for soybeans
Improve early season growth and overall vigor
Maximize plants in cases where pH is off
Alleviate drought stress and environmental stresses
Enhance soil nutrient uptake and availability

Liqui-Grow Agronomy Field Advisors can help determine these goals and objectives for your farming operation!

Ok, what products should I use?

Endless biological products are available to be used throughout the season. This can be confusing and intimidating. So we have broken down timing and listed some below in order of use during the growing season

Biologicals in Seed Treatments, In-Furrow Starters & Planter Boxes

Seed Treatment

Liqui-Grow has different options in soybean seed treatments for biological products. The soybean inoculant we use has biological activity to provide a shield around the roots and help with water and nutrient uptake.

Stater or Planter Box

If your planter has in-furrow corn starter capabilities, ask about MicroAZ! MicroAZ has shown a + 5bu advantage more than 70% of the time in the Liqui-Grow research fields. MicroAZ is a bacterial inoculant that enhances root hair development, which is important for nutrient and water uptake. If you are using microbes in a starter fertilizer, we need to know if they are compatible with fertilizer. Liqui-Grow has many research results and compatibility test results on biological products being added with starter fertilizer. Before you conduct your own on-farm research, ask an Agronomy Field Advisor. We can help you with that information!

If starter isn’t an option, we also have biological products that can be added to planter boxes to provide microbial benefits. Generally, we can expect similar results using microbes or biological products in planter boxes or starter fertilizers.

Biologicals In-Season

Soybeans

Soybeans are a yield-building factory. Liqui-Grow Research has found Polyamine MicroPack, has shown a yield increase when added into V3-V4 herbicide treatment. (2nd pass soybean herbicide) This product has a combination of micronutrients and amino acids.

Corn - There are multiple products showing yield increases, including Polyamine B, Taurus Sulfur, BSure & ReleafOS. Releaf OS is not an amino acid based product; it is still a biological product because it is derived from a living organism.

Liqui-Grow has been testing biological products for years - in fact, one video below is 6 years old!

Shelf Life and Storage on Biologicals

As always, check the labels to see how to store these types of products! Anytime you are working or handling a biological product, it is best to consult the label on proper storage and shelf life to maximize the benefits of those products.

If you would like to know more about the biological industry, there are many resources, but the Biological Products Industry Alliance is an organization promoting the awareness of biological products in multiple industries and an overall good place to start.

Sulfur on Soybeans

November 26, 2024November 26, 2024 ATS soybeans Sulfur

Free atmospheric sulfur is almost non-existent these days. So much like corn - farmers need to add sulfur to their fertilizer blend for our soybean crop. Responses to sulfur applications seem to vary - but soil is soil - and we see a more consistent result to the addition of sulfur in sandier soils with low organic matter. We recommend applying sulfur in the spring if you are working with sandy soils - if you’d like to know the science behind that, ask a Liqui-Grow Agronomy Field Advisor. We also tend to see a more consistent result in fields planted early with a higher % OM. - we think about the fields in our Northern territory. This could be because the soil has not yet warmed up enough to mineralize the nutrients the soybeans are looking for. Think about a frozen dinner - it’s not very good to us still frozen.

The Results

Aledo showed a 3.3 bu increase from the check to ATS being added at the planter.
Hampton showed 11.6 bu increase from the check to ATS being added at the planter.
The average between the 2 locations was just shy of 7.5 bu by adding ATS with the planter. So, it really does show that our soybeans plants are deficient in sulfur - much like corn.

How to Feed the Crop

ATS is a great form of sulfur that can go on preplant or preemerge in soybeans. Do not apply ATS to a crop once it has emerged, and do not apply ATS as a foliar application. ATS can be put on with the planter as Jake did in his research trials, just NOT in-furrow.

If you haven’t tried ATS on your soybeans yet - try a few fields - or strips in one field. To learn more about sulfur needs for your soybean crop - contact your Liqui-Grow Agronomy Field Advisor today!

Questions? Give us a shout!

Text us at 564-220-2508 or email questions@liqui-grow.com.

Liqui-Grow

Barriers to Entering the Leaf

In simple terms: An adjuvant helps the herbicide penetrate the plant more easily, allowing it to kill the weed.

Adjuvant Jobs

Environmental Conditions that reduce herbicide uptake:

Plant Physiology that reduces herbicide uptake:

Drift/Deposition Adjuvants

Tank Mixes and Labels

Summary

Questions? Give us a shout!

Award Recipient

Questions? Give us a shout!

Weather

Waterhemp Characteristics

Giant Ragweed Characteristics

Shade out the Rows

Cover Crops

Tillage

Herbicide Use

Questions? Give us a shout!

4 Quarters to the Game!

V4-V5 Corn Application

Liquid vs. Urea

Late Season Application - We Can Do It. Is Late Season the Right Time?

Conclusion

UAN vs Urea Sidedress article

Yellowing and Dark Green Spots in Soybean Fields

What is IDC?

These are all great clues to solving your problem fields!

How bad does it need to get before I worry about IDC?

What to do about IDC?

Creation of Variable Rate Seeding Recommendation

Corn - How low can you go? Wait, where are you going, and who’s going with you?

Soybeans - here’s the secret…there is no secret.

Here's Why:

Now, how does this affect starter fertilizers?

Field Study

Franzen D. and J. Gerwing. 2007. Effectiveness of using low rates of plant nutrients. North Central regional research publication No. 341. http://www.extension.umn.edu/agriculture/nutrient-management/fertilizer-management/docs/Feb-97-1.pdf (accessed 8 of Sept 2015).

Video

Why this difference?

Don’t forget appropriate adjuvants

The Extras:

First off, why do we hear so much about biologicals?

Biologicals - what are they and what can they do?

The When and Why of Biologicals

Ok, what products should I use?

Biologicals in Seed Treatments, In-Furrow Starters & Planter Boxes

Seed Treatment

Stater or Planter Box

Biologicals In-Season

Soybeans

Shelf Life and Storage on Biologicals

Sulfur Application

The Results

How to Feed the Crop

Questions? Give us a shout!

Menu

In simple terms:
An adjuvant helps the herbicide penetrate the plant more easily, allowing it to kill the weed.