Crops

Choosing the right adjuvant for the job

Anything that prevents a herbicide from reaching its target, deactivates a herbicide or reduces exposure to the target weed is a hur­dle to effective pest control. Often, these hurdles seem daunting. While matching applications to proper en­vironmental conditions is critical for highly effective weed control, there are tools we can use to overcome threats to herbicide performance— even in optimum circumstances. Among these are properly selected, high-quality adjuvants.

Adjuvants are often one of the least understood but most effective tools to enhance crop protection performance. Depending on the product, a properly selected adjuvant can prove invaluable to increasing the likelihood of plant uptake. Adjuvants condition water to prevent herbicide deactivation, reduce drift fines and make mixing and tank cleanout easier. The key to successful adjuvant use is knowing the right product for the job.

Adjuvants typically fall under three basic categories: activators, spray modifiers and utility products.

Activators

These include non-ionic surfactants (NIS) such as MFA’s Astute, crop oil concentrates (COC) such as MFA’s Relay, and methylated seed oils (MSO) such as MFA’s SoyPlus. NIS, often called “wetters” or “spreaders,” are designed to reduce surface ten­sion of a water droplet. This action causes a droplet to flatten out and spread across a leaf surface, increas­ing the surface area in contact with the leaf. NIS products contain ingre­dients such as organosilicones that have some penetrative properties, but typically oils (COC and MSO) are considered true penetrants. While oils provide less reduction in surface tension than NIS, they increase penetration through barriers such as waxy leaf cuticles.

Selecting the proper activator is a balance of increasing weed control without adversely affecting crop safety. For example, oils can add to weed control, especially in unfavor­able conditions, but can have nega­tive effects with certain herbicides.

More and more products such as Xpond, a high-surfactant oil con­centrate (HSOC), are being used be­cause of their combined effects as a spreader and oil. Lower oil use rates makes them safer on crops without sacrificing weed control.

Spray modifiers

These products vary in utility and include fertilizers, water condition­ers, humectants and deposition and retention aids (DRA). Fertilizers such as ammonium sulfate (AMS) are of­ten used as a water conditioner. AMS can neutralize hard water ions that deactivate herbicides such as glypho­sate but can also improve uptake of herbicides by introducing ammo­nium to the solution. Problems with use of ammonium-containing fertilizers include high volume re­quirements and incompatibility with newer dicamba formulations due to increased volatility. Low-use alter­natives are available. Some contain ammonium, such as Waypoint, and some don’t, such as Impetro II.

Humectants aid weed control by increasing a droplet’s drying time. Extending the time a herbicide remains in liquid form can improve uptake by weeds, increasing control. In MFA’s Crop Advantage lineup, humectants have been added to Impetro II and AMS Advantage.

DRAs are used to control drift and minimize droplet bounce to reduce off-target movement and leaf retention. Compatibility and consid­erations with tank-mix partners are important, so choose DRA products wisely. PowerShot and SoyPlus HD contain both penetrants and DRAs, and MFA’s Impetro products contain DRAs in addition to humectants and water conditioners.

Utility products

This broad category of adjuvants covers several products that mostly work to increase the ease of handling pesticides. Included in this group are defoamers, tank cleaners such as Evict and compatibility agents such as Convert that can prevent or even remedy certain tank-mix issues.

With such a wide array of func­tions and compatibility, adjuvant selection is challenging. To compli­cate matters further, adjuvants are not regulated like pesticides, and the market is full of untested, inferior products claiming to be of equal quality. For example, you would assume an NIS labeled 90/10 would contain 90 percent surfactant. In fact, the label only implies 90 per­cent active ingredient, which could be any number of things and make a typical rate ineffective.

The uncertainty in the market is why MFA developed its Crop Advan­tage line of adjuvants. We subject our products to third-party testing by the Council of Producers and Distributors of Agrotechnology to ensure the highest quality. Growers can be assured that products with a Crop Advantage label adhere to MFA values of honesty, integrity, account­ability, innovation, technology, cus­tomer partnering and stewardship. For more information, visit with your local MFA crop specialist.

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Make sure your N gets in

SuperU corn IMG 7025SuperU fertilizer makes sure this corn crop will receive the nitrogen it needs with protection against volitalization, dentrification and leaching.Where did fall 2018 go? Harvest dragged on and on. We had little to no movement of fall fertilizer, fall herbicide, and, for that matter, timely planted cover crops. It seems we say this every year, but this past fall will certainly be remembered— either for harvest at Christmas or lack of field work being done.

Now, however, it’s time to focus on the spring ahead. As I men­tioned, very little nitrogen has hit the ground. Yes, a few areas got a good run around the holidays, but, for the most part, we are at ground zero.

For many, anhydrous is the pre­ferred N source in MFA’s trade area. Its high percentage of nitrogen, ef­fectiveness and application methods make it a great fit. However, supply can be tight, which I think will hap­pen this spring.

Looking at N options for spring application, we have to be realistic. We do have other choices. Available nitrogen sources include urea, urea with N-Guard, urea with Instinct, SuperU, UAN and anhydrous. No matter which form you choose, nitrogen stabilizers are crucial to protect your plant food investment.

I’ve discussed urea before. If it is surface-applied, we must protect it with nBPT, the active ingredient that combats the urease enzyme and limits volatility. You read about this in last month’s article on our Train­ing Camp results. MFA’s nitrogen stabilizer N-Guard is an approved nBPT that is proven to be one of the best volatilization inhibitors on the market. Volatilization is the most common form of nitrogen loss with dry fertilizer products.

Now is also a good time to cover SuperU, a stabilized urea-based gran­ule that contains nBPT and dicyan­diamide (DCD). The nBPT provides above-ground protection, and DCD protects the nitrogen below ground.

Urea with Instinct nitrogen sta­bilizer also provides below-ground protection. The active ingredient in Instinct is encapsulated nitra­pyrin, an organic compound that slows down the soil bacteria that converts ammonium to nitrate, keeping nitrogen in the ammonium form longer. Instinct is essentially N-Serve for urea.

If UAN is your nitrogen source, it must be protected, too. UAN is 50 percent urea and 50 percent ammo­nium nitrate. While the ammonium nitrate isn’t volatile, the urea portion is, and they are both subject to below-ground losses. Agrotain Plus is the product we use in this situa­tion. It has nBPT and DCD that will protect the nitrogen from all three forms of nitrogen loss: volatilization, denitrification and nitrate leaching.

We often get questions about using N-Serve in spring applications of anhydrous. Is it needed in the spring? Research has shown that we can see a 7 percent advantage from fall-applied nitrogen with N-Serve and a 5 percent advantage when it’s applied in the spring. Another question that comes up is about how long the protection from N-Serve lasts. A rule of thumb is 90 days for fall applications. Days are counted from application until temperatures drop below 40 degrees. Then the counting starts again in the spring when soil temperatures warm above 40 degrees. Generally, with spring applications we can expect eight weeks of activity from an April 15 application, seven weeks from a May 1 application, and six weeks from a May 15 application.

While many of you prefer an­hydrous, yields with SuperU have shown to be equal to that of anhy­drous with N-Serve.

A pound of N is a pound of N, as long as it’s still available for the crop when it needs it. This spring, whether you’re applying and pro­tecting anhydrous, urea, Super U or UAN, visit with your local MFA Agri Services or AGChoice for the best option to use on your farm.

More from this March Today's Farmer Magazine Issue HERE .

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Putting dicamba to the test

ON OCT. 31, THE EPA MADE its much-anticipated announcement that dicamba registration will be extended for over-the-top use on cotton and soybean plants genetically engineered to resist the product.

The approval is for two years, and the EPA will consider the issue again in 2020. In its news release, EPA Acting Administrator Andrew Wheeler said the registration extension was made because dicamba has proven to be a valuable weed-control tool for America’s farmers.

The decision is welcomed by MFA Director of Agronomy Jason Weirich, who agreed that growers need the dicamba-tolerant technology in the Roundup Ready Xtend crop system as a weapon against the increasing number of herbicide-resistant weeds.

“We need dicamba technology to combat weed resistance, but we have to be good stewards,” he said. “Protecting the technology for the future is important, not only from an economic standpoint but also an environmental standpoint.”

This past year, Xtend seeds, which are tolerant to both dicamba and glyphosate, were planted on some 40 million acres, representing nearly half of all soybeans and cotton in the United States. Bayer, which now owns Monsanto, expects that total to grow to 60 million acres in 2019.

In the two seasons that Xtend technology has been commercially available, growers have seen success in both weed control and yield response, Weirich said. However, there have also been widespread complaints that dicamba herbicides drifted and harmed non-tolerant crops.

To help mitigate those issues, EPA imposed additional restrictions on dicamba spraying. Starting in 2019, only certified pesticide applicators will be allowed to spray the chemical, and applications must end 45 days after planting soybeans and 60 days after planting cotton.

MFA placed its own stringent protocols on the sale and use of dicamba during the last growing season to minimize the risk of damaging non-targeted plants. A network of “sentinel plots” across MFA’s service territory allowed crop scouts to track soybean growth and provide timely information to applicators about crop progress. MFA applicators were alerted to stop spraying when the majority of soybeans in their area reached the R1 reproductive stage, when dicamba injury can do the most harm to non-target plants.

That protocol will continue in 2019, Weirich said.

“We consider our system to be a success,” he said. “In 2018, we didn’t have nearly as many complaints as we had in 2017 and actually sprayed more acres of Xtend soybeans.”

Weirich and his team of agronomists are also conducting their own research to help understand more about what causes off-target dicamba movement. Trials at MFA Incorporated’s Training Camp site in Boonville, Mo., this past summer helped shed some light on best practices in applying dicamba products, Weirich said.

“When we set up these plots, we had just come out of 2017 season, where we saw a significant amount of off-target movement, and we were looking for reasons why,” Weirich explained. “This trial specifically looked at different tank mixes and their role in dicamba volatility. There’s been a lot of talk about how ammonia sulfate, different salts in glyphosates and other issues could cause off-target movement.”

To encourage conditions for dicamba volatility, Weirich and the MFA agronomy team used 15-by-5-foot plastic-covered hoop houses placed over soybeans at the V3-V4 stage in mid-June. A flat of soil taken from the site was filled to capacity with moisture and treated with either straight dicamba or a dicamba mix. The flats of soil were sprayed more than 50 yards away from the plot so there was no risk of contamination.

The trial included 14 different treatments. Each flat was placed underneath a hoop house over two rows of soybeans and left for 24 hours.

“The temperature got up to 97 that day,” Weirich said. “It was hot and humid. This trial was designed to make the environmental conditions conducive to volatility.”

Six of the 14 flats were treated with straight dicamba: Clarity, which is not labeled for over-the-top application on soybeans, and two approved formulations, Engenia and XtendiMax. Each was applied in both a 1⁄2-pound and 1-pound rate.

“Clarity showed visible damage to the ends of the 15-foot tunnel. It’s a non-improved formulation, and it definitely showed increased volatility,” Weirich said. “With Engenia and XtendiMax, movement was very minimal, no more than 1 foot away from the flat. We couldn’t tell much of a difference between the two products.”

Other lessons learned from the trial, Weirich said, were the detrimental effects of ammonium sulfate (AMS), commonly used as a water conditioner in glyphosate tank mixes. In the Training Camp plots, a full rate of AMS with both XtendiMax and Engenia showed significant damage compared to applications of straight dicamba.

“We saw severe cupping and stacked nodes a good 5 to 7 feet outside the tunnels on both ends,” Weirich said. “We also tested a 1⁄10 rate of AMS, and also had significant damage. In fact, visually, I couldn’t tell the difference between the full rate and 1⁄10 rate.”

The take-home message, he continued, is to meticulously clean out application equipment before spraying an Xtend field, even if the sprayer is moving from a Roundup Ready field to a Roundup Ready Xtend field.

“What this tells us is that a very small amount of AMS is detrimental to Xtendimax or Eugenia,” Weirich said.

Another section of the trial compared different formulations of glyphosate with varying salt content, which has also been suspected in dicamba volatility. One plot looked an application of Xtendimax with Roundup PowerMax and another tested Xtendimax with Durango, a glyphosate product from Dow AgroSciences that is not labeled for application with dicamba.

With the XtendiMax-PowerMax mix, there was movement to the end of the tunnels with increased damage near the flats compared to the straight dicamba product at the same rate. With Durango, however, there was significantly increased injury.

“There are some best practices out there to minimize volatility, and at MFA, we’ve taken the stance that we will use PowerMax, based on the research and data out there,” Weirich said. “This trial shows us there is a big difference in the various salt formulations of glyphosate and the effect on volatility.”

Weirich acknowledged that this trial was a one-year demonstration with the main goal of educating MFA employees about the risks associated with off-target dicamba movement and the importance of proper tank cleanout. He said MFA plans to continue the study next summer.

“Overlapping residuals are still key for the future of dicamba or any technology coming down the pipeline,” he said. “At MFA, we’re doing everything we can to manage this technology by training our applicators to know the risks and follow all federal and state guidelines. We need this technology, and we want to make sure we are good stewards.”

For more details on the dicamba movement trials at MFA’s Training Camp, visit mfa.ag/DicambaResearch.

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Nitrogen models can improve nutrient stewardship

What a year we’ve had—from nearly perfect planting conditions to a drought that affected most of our trade territory to more rain during harvest season. Is this the new norm? Maybe.

In most cases, we’ve seen higher yields in corn this year than we expected, but we know that yield variability across fields is normal. We’ve also seen the same when we look at nutrient values. Do they always correspond? Do the high-yielding spots always have the higher nutrient values? The short answer to both of these questions is, “No.” Sometimes the areas with lower nutrient levels might be your highest-yielding spots in the field. This may sound confusing, but these areas are removing more nutrients than others. So it only makes sense that we would put back different rates of fertilizer. Right? This is a common issue we discuss when visiting with producers.

This variability in nutrient values can cause headaches when planning how to replace the P and K that your crop removed. While the flat-rate method of replacing what the whole field averaged has worked in the past, I believe that variable-rate application of nutrients is one of the best management practices that we should all consider to help minimize environmental issues and increase yield. This allows your fertilizer dollar to go further. Nutri-Track programs have a strong focus on nutrient stewardship. We want to put your fertilizer where it will get you the biggest return.

As you may have seen, the first week of October we announced that MFA is partnering with Adapt-N to offer Nutri-Track N recommendations with all of our current Nutri-Track acres (see related story on page 5). This program allows our agronomists and precision specialists to work with producers to employ a nitrogen model to determine optimal rates for your fields. This model takes in a number of factors to determine the right N rate. The tool evaluates organic matter, soil type, rainfall and other variables that affect nitrogen. We then use this model-based N recommendation to have a conversation with you to find efficiencies in nutrient stewardship as well as increasing yield.

Over the past couple of years, two of our producers have been named 4R Advocates, a national award for nutrient stewardship. The 4Rs promote general best management practices that are the foundation of our precision programs: the Right Source, Right Rate, Right Time and Right Place. While this may sound simple, it can also be very complex. The 4R program is important, because it demonstrates our commitment to soil stewardship, proper fertilization practices and the economic benefit of these techniques.

I also feel strongly that the average person, not involved in agriculture, misunderstands the concept of fertilization in commercial farming. The 4R program may help dispel some misconceptions by the general public. For more information, visit www.nutrientstewardship.org or stop by your local MFA.

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Do you know your soil?

Fall always brings up conversations about soil management. Typically, when we think of soil considerations, we think about fertility. “How much N, P and K should I apply?” is generally the first question that comes to mind. Soil tests and yield maps are great tools for answering that question. Recommendations for these nutrients and other soil amendments such as lime are critical management aspects and perhaps the most important to address. However, fertility levels are only a portion of the insight growers can access through MFA’s Nutri-Track program.

Understanding physical soil properties and how they fluctuate across a field can provide valuable clues to address fertility management, hybrid and variety selection, planting rates and even weed control concerns. Among key properties are soil texture—the amount of sand, silt and clay in the soil—and organic matter. Both of these soil characteristics can impact drainage, resistance to compaction, nutrient-holding capacity, behavior of residual herbicides and other factors. Soil characteristics even impact the spectrum of weed species in the field because certain soil types are more conducive to certain weeds.

How do we manage not only variable soil fertility but also variable soil properties? There are many solutions for that: variable-rate nitrogen, nitrogen modeling, comparing yield zones to soil zones, variable-rate seeding, multi-hybrid planting or even something as simple as selecting a hybrid well suited for the unique conditions of your field. But, before any of these solutions can be implemented, it is critical to understand which soil properties you have. Traditionally, to do this, we used soil maps developed by the NRCS more than 50 years ago without the level of technology we have today. Now we have innovations such as Veris toolbars that use electrical conductivity (EC) and optical sensors to more accurately identify soil zones. These values relate closely to soil texture and organic matter. The chart in Figure 1 shows examples of how these readings can be used to measure zones and the other insights they can provide.

Just below the chart, the photos of soybeans in Zone 1, left, and Zone 4, right, depict the variability of the soil properties in the field. From these images, it’s clear that the varying soil types and properties greatly impacted the growth and development of the soybean crop, especially in a dry year such as 2018. Beyond the differences in canopy and plant height, there was a significant difference in the number of pods and blooms.  

It’s not surprising that coarser soils with lower water-holding capacities should be more prone to stress, but we did not anticipate the stark difference in weed pressure based on soil type. The coarser soil had a much higher level of weed pressure, likely due to multiple factors such as reduced canopy and differing soil/herbicide interactions.

So now that we know where these soils differ and how nutrients, crops and pests respond differently to these zones, how can we more effectively manage them? Zone 1 might respond better to lower seeding populations, a more defensive corn hybrid and lower cation exchange capacity. Coarser soil texture will not hold on to nitrogen fertilizer as well as soil with higher cation exchange capacity. Zone 4 may facilitate potentially higher-yielding hybrids at higher populations, and it may not be as risky to apply high rates of N to it.

When evaluating plans for next spring, soil fertility is critical, but it is not the only soil property to consider. Advanced EC and organic mapping solutions from MFA’s Nutri-Track program can provide valuable insights and a basis for fertilizer recommendations, seeding information, aerial imagery and even pest scouting reports. It all starts with understanding the underlying soil properties and the extent of how those properties vary across the field.

For more information on EC mapping, contact your MFA precision specialist or Nutri-Track consultant.

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