Crops

Shortages of P and K can limit production of your crop

What is your P and K fertilizer program? If you’re basing your rate on what you have always done, have you ever questioned why you apply what you do? It’s pretty easy to get stuck in a rut and use the same fertility program year after year without looking at it more closely, as long as yields keep increasing.

If this sounds familiar, we should talk.

The basics of soil fertility haven’t changed much over the years, but that doesn’t mean we should take it for granted. Our plants are factories that need a certain amount of nutri­ents to operate at peak capacity, just like an automotive manufacturing plant. When something is in short supply—whether that is phospho­rus or a computer chip—both types of plants are going to throttle back production until they can get all the materials they need. How do we avoid this shutdown? In simple terms, it’s just a matter of under­standing supply and demand.

Let’s start with supply. The vast majority of nutrients are supplied to the plant from the soil solution. While the soil can store significantly more nutrients than our plants will demand in a single season, those nutrients are not all readily avail­able for uptake. Many nutrients are bound tightly with other com­pounds in the soil. They are essen­tially in long-term storage, which means that it takes a significant amount of time for them to arrive in soil solution for the plant to use. As the plant takes nutrients from the soil solution, replacement nu­trients are transferred from “storage” to restock the system. The processes that facilitate that movement are not instant.

Soil testing can help us manage and understand this process. Many diverse and complicated factors control how much of the total quantity of nutrients contained in the soil are available for plant uptake, making it nearly impossible to estimate what is readily available for a plant to use. Soil testing ap­proaches this problem in a different way. Chemicals are used to flush nutrients out of the soil sample, and then the nutrients that are re­leased are measured. The chemicals and methods are designed to closely mimic how a root would extract nutrients from the soil. By compar­ing how yield responds with the addition of readily plant available fertilizers versus the known soil test value, we can determine where the soil is providing enough nutrients for complete plant growth.

Again, a soil test is not necessarily an inventory of all the nutrients contained in the soil, it’s more like the amount of nutrients that are in soil solution ready for plant uptake. To relate it to the factory model, it tells us how many computer chips are actually sitting in the factory that we can use to build pickup trucks today.

If the soil test tells us about nutrient supply, why does demand matter? Demand tells us how much fertility is hauled away in a grain truck or a bale of hay. We use that number to understand what we need to put it back into inventory for the next season. Demand is fair­ly easy to calculate. You just need the nutrient concentration in the crop and the yield. It may surprise you to know that nutrient concen­tration is actually easy information to find. Many of the crops we grow are used in livestock feed, and much work has gone into analyzing that feed for its nutrient concen­trations to create a balanced ration. For the most part, the nutrient con­centrations we use for crop removal estimates are based on long-term averages from feed information.

Yield can come from several different sources, whether it is your long-term yield average, yield goal or actual yield data. We can use any of those numbers along with the nutrient concentration to arrive at the total nutrient removal we can expect.

Admittedly, it’s easy to ignore your fertility program and just do what you’ve always done without think­ing about it. But like most decisions on the farm, it pays to understand how fertility is going to affect your plants in the field. If they face a shortage, it doesn’t matter what else you do. Those shortages are going to limit production.

As you build your fertility plan this year, I encourage you to figure out your supply and demand to ensure plant nutrition doesn’t limit your production. Reach out to your local MFA if we can help you in this process.

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Invest in P and K instead of Fe this fall

Supplies of toilet paper and hand sanitizer aren’t the only things negatively affected by COVID-19. Tractors, combines, farm equipment and pickup trucks are also hard to find these days. Many industries are facing a lack of labor and raw mate­rials, an issue projected to continue through at least 2022. Disruptions all along the supply chain have caused shortages of steel, plastics, microchips and tires, and many suppliers are facing a labor crunch because of the pandemic.

As a result, the tractor supply in North America is the tightest in 18 years, and precision equipment suppliers have been encouraging early orders to avoid delays and shortages of guidance systems and planter control systems. Some companies are so far behind that their dealers were taking orders for planters for the 2023 crop season in June of this year.

Not 2022. 2023.

This got me to thinking: At the end of the year, instead of invest­ing in iron (Fe) for your farming operation, why not invest in fertility (P and K)?

As a precision manager for MFA Districts 3 and 6 on the east side of Missouri, I help a team of precision specialists manage our Nutri-Track high-yielding fertility management system. We use 2.5-acre grid sam­ples to develop plant food recom­mendations that allow our growers to improve yield and be more efficient with their fertilizer dollar. Nutri-Track’s variable-rate fertility recommendations are developed specifically for each operation on an acre-by-acre basis.

Much of that work is done in the fall. Many soil samples are taken, and many variable-rate prescrip­tions are developed and applied, but we should—and could—be doing more.

Applying phosphorus and potas­sium in the fall between the end of harvest and the first freeze will re­plenish essential nutrients removed from the field and ensure they are in place for next year’s crop. We all know that compacted springs are beginning to feel like the rule instead of the exception. Widening the window for P and K application and moving acres to be fertilized from spring to fall can help lessen your stress in the busy season. Phosphorus and potassium applied in the fall, along with sulfur and zinc, will be ready to go to work for you in the spring.

It’s true that MFA’s extensive infrastructure gives us the ability to apply a lot of product in a short time during the spring rush. Plant foods are often delivered to the fer­tilizer plant, and then immediately loaded on to a truck and applied to a field within hours. That doesn’t mean, however, that bottlenecks don’t happen. Much of our dry fertilizer comes in on river barg­es. When rivers get out of shape due to spring floods (or a bridge in Memphis develops a crack and threatens to fall into the Mississippi, like we saw this past spring) getting phosphorus and potassium can be a challenge.

If you apply fertilizer in the fall, you won’t need to wait until the spring weather cooperates or worry about barge shipments being de­layed. There are many other reasons why fall applications are a good investment. Soil moisture is gener­ally lower in the fall, lessening the risk of soil compaction compared to wet spring soils. Equipment and applicators at your local MFA are usually more available in the fall. And fall fertilizer prices tend to be lower than spring prices.

While I’ve mostly focused on P and K here, fall application of an­hydrous ammonia is also common in much of our trade territory. This is a good practice, as long as you are also planning an in-season top-dress application and protect­ing that nitrogen with a product such as N-Serve or Centuro. These actually work to protect against N loss instead of just claiming to—but that’s a subject for a different day.

To me, it boils down to this: in most instances, on most soils, there is no good reason not to apply phosphorus and potassium in the fall. It can give you a leg up in the spring, provide some much-needed flexibility and allow you to alleviate some of the stress of having a lot to do in a short window.

New tractors, combines and planters may be hard to find right now, but fertility is one purchase you can always count on. So this fall, when you’re thinking about the investments to make in your farming operation, forget about the iron (Fe) and focus on the fertility (P and K).

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Waging war against pesky pigweed

Each growing season, produc­ers face multiple challenges when trying to plant their crops. Too much or not enough rain. Changes in chemical trade names and new premixes. New equipment, software and “smart” technologies to consid­er. On a positive note, commodity prices for grain and cereal crops have been on the rise, a relieving tune when compared to prices over the last seven years. I hope this is a good year for our growers’ pocket­books.

Weeds, on the other hand, care little about market trends and capitalize on our missed opportuni­ties and periods when stress levels are high. The pigweeds—Palmer amaranth and waterhemp, namely— have made headlines and likely are the focal point of many conversa­tions among growers and retailers in recent years. A keyword search for Palmer amaranth and water­hemp on the North Central Weed Science Society website revealed 30% of its published poster and paper abstracts in 2020 included one or both of these weeds, which means significant research contin­ues on both species. I don’t really see that trend changing anytime soon. Note that the members of the North Central Weed Science Society not only include Missouri but also Colorado, Illinois, Indiana, Iowa, Kansas, Kentucky, Michigan, Minnesota, Nebraska, North Dako­ta, Ohio, South Dakota, Wisconsin, Wyoming and the Canadian Prov­ince of Ontario, and those search results indicate that these weeds are significant pests in many areas outside the Show-Me State.

Populations of waterhemp have become resistant to herbicides that contain the active ingredients glyphosate and lactofen. Some of the first reported cases date back to around 2008. More recent surveys (2015-2017) conducted by Dr. Kevin Bradley’s team at the University of Missouri in Columbia show the majority of waterhemp collected from Missouri fields were resistant to chlorimuron and glyphosate, and one field had plants not controlled with 2,4-D, atrazine, chlorimuron, fomesafen, glyphosate or mesotrione.

Palmer amaranth doesn’t seem to be as widespread as waterhemp in Missouri but certainly has a foothold farther south. For most of 2020—and at least the first half of 2021—the world has focused on mitigating the spread of COVID-19 and its lethal variants, but at the border of our southeast trade territory another issue has arisen: reports of Palmer amaranth control failure with glufosinate in two northeast counties in Arkansas. As a weed scientist by training, this saddened me to read. My intent is not to scare or signify the fight is hopeless but to inform readers of what is going on in our backyards. We are in a battle to isolate these populations as much as possible to prevent pollen and seed spread and to protect the technologies that we have left.

Knowing what we know about these species, we still have options. Protecting corn and soybeans from weed competition four to six weeks after emergence is necessary to minimize yield loss. Soil residu­al herbicides applied at planting followed by in-season overlapping residuals, including a Group 15 herbicide (such as Anthem, Cinch, Dual II Magnum, Outlook, War­rant and Zidua), have shown to be effective in managing these species before they emerge from the soil. Add an effective post-emergence herbicide (tailored to the soybean trait platform) for those weeds not controlled pre-emergence.

For various reasons, many Mis­souri farmers have planted cover crops. Fortunately, high biomass cover crops such as cereal rye make it difficult for small-seeded weeds to establish and penetrate through the residue layer. Sufficient closure of the seed furrow is critical to maximize soil-to-seed contact and achieve uniform crop emergence. Some challenges exist with cover crops, no doubt, and may not be suited for areas where soils poorly drain. Terminating the cover crop when it’s larger may prevent soil residual herbicides from contacting the soil. Soil-applied herbicides must be in the soil solution to be taken up by germinating seeds. However, planting conditions may deteriorate when cereal rye is termi­nated early because the once living cover crop is no longer extracting moisture from the soil.

Going forward, I’m optimistic that technology and adapting our production practices to exploit weaknesses in the plant’s biology will aid in managing these prob­lematic weed species. Visit with the agronomists at your MFA affiliate or feel free to contact me if you want more info on weed-control options for this year’s crop.

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Meet MFA's new director of agronomy

Helping growers economically manage pests has been my passion for the past decade—from my un­dergraduate studies to my graduate research to my most recent work with the USDA-ARS Sugarcane Re­search Unit in southeast Louisiana. There, I focused on integrated weed management strategies to control annual and perennial grasses that are especially problematic for sugar­cane growers.

While Missouri has its fair share of specialty crops, sugarcane isn’t one of them. But weed control is a common struggle for producers, no matter what they’re growing. It is extremely rewarding coming back to the same fields with much lower weed densities years later after having a discussion on results from what research has shown.

I’m not only passionate about agricultural research and its results, but I’m also a strong believer that being stewards of our natural re­sources and passing down knowl­edge are essential for the success of future agriculturalists and rural communities. I’m bringing that philosophy to my new role as MFA Incorporated’s director of agronomy. You’ll hear from me regularly here in Today’s Farmer as well as other MFA print and online resources.

Though I’ve spent the past four years in Louisiana, I’m no strang­er to Missouri agriculture. I was raised near Washington, Mo., which has long been known as the corn cob pipe capital of the world. During the summers as a youngster, I would help my uncle put up hay and bushhog pastures. I also showed hogs at the Wash­ington Town and Country Fair for 11 years. My family had several rows of blackberries, raspberries and strawberries, which were sold locally. The trade-off, if you will, was us kids did a lot of the weeding throughout the spring and sum­mer—all by hand.

I went to the University of Mis­souri in Columbia and received a bachelor’s degree in crop manage­ment in 2011 and a master of sci­ence in plant, insect and microbial sciences in 2013 under the direc­tion of Dr. Kevin Bradley. In 2017, I completed my Ph.D. in botany and plant pathology at Purdue Universi­ty with Dr. Bill Johnson. Managing glyphosate-resistant giant ragweed, waterhemp and Palmer amaranth made up the bulk of my thesis and dissertation research.

I’m joining MFA at a busy time for our agronomy team and grow­ers. I’ve already made field visits across the trade territory, including our two training sites in Boonville and east of Columbia where variety, fertilizer, seeding rate and seed treatment trials will be conducted. My first several months will require significant time investment in get­ting up to speed with the team and products MFA offers to growers.

In many ways, I compare this orientation period to what it takes to prepare for the annual student weed science contest I participat­ed in as a graduate student. To be successful, it required everyone on the team to be accountable, come prepared, communicate and work together effectively. This was espe­cially critical for the team sprayer calibration competition, in which you were not only evaluated on ac­curacy but also efficiency. My team did especially well in the event, reflecting our ability to foresee and anticipate what we needed to do next. In some instances, sprayer tips were intentionally damaged, which required team members to spend more time finding a func­tional tip of the appropriate size and spray angle. Team members would never sit and wait—they would automatically see what we needed to do next to shave off seconds from our time. This is what made us successful.

This philosophy has not changed much at all to where we are today. I’m looking forward to helping bridge MFA’s sales, agronomy and precision folks into a more cohesive and interactive group. At the end of the day, we all have something to learn from one another. I also want to encourage an open mind­set. A healthy debate in a respectful manner is good and helps move us forward as a team.

I’m eager to put my education, background and experience to work for MFA personnel, growers and customers across our geography. With spring planting season well under way, this is the time for our agronomy team to shine. I’m glad to be part of it.

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Agricultural wetlands attract diversity of wildlife for hunting and more

Even if you don’t live near a natu­ral wetland, practically anyone with access to a farm or ranch can turn fields into outstanding waterfowl habitat. Flooding crop fields in the fall and winter to attract ducks, geese and other wildlife is a popular land management tool for hunters and wildlife enthusiasts.

It’s not just about mallards cupped over decoys. There are countless other species that count on quality wetlands for their life cycles and migrations. Ducks and geese are attracted to grain and weed seeds, while shorebirds, wading birds and mammals visit flooded fields in search of fish and invertebrates.

Waterfowl migrations are ex­tremely complex in both spring and fall, but there are some manage­ment actions that you can do now to ensure adequate amounts of the food these birds are seeking.

Corn is king

The age-old deer hunter question, “What should I plant in my food plot?” is rarely heard in the water­fowl world. For ducks, you want corn. First of all, corn produces a high-carbohydrate food that is quick and easy for ducks to access even in cold, frozen, challenging conditions. But to waterfowl hunt­ers, corn can be much more than just duck food. A corn crop also provides tall cover that can conceal hunters from weary waterfowl.

Corn planted in rows near open water can also trigger a duck’s inherent quest for a “hemi-marsh,” consisting of about 50% open water and 50% standing vegetation. Pud­dle ducks such as mallards are most attracted to this type of flooded habitat. It’s indicative of wetlands that have drawn down to allow for plant germination and then reflood­ed. It’s where ducks can find ample food to fuel migration.

When planting corn in a wetland area, here are other considerations:

1. Make food plot plantings where you can flood the crop with at least 12-18 inches of water.

2. Select varieties with fewer days to maturity. Planting dates in low, wet areas are typically later.

3. Select varieties that are shorter in stature with a lower ear height. The lower the ears, the less wa­ter depth needed for waterfowl to reach the grain.

4. Use a traited variety to simpli­fy over-the-top weed control and prevent insect damage that could cause lodging.

5. Make a planned nitrogen topdress application. Wet soils in low areas are not good candidates for preplant-only N management. Ponded water and warmer soil from later planting may lead to significant N losses.

6. Plant corn near areas that can easily be mowed to create open water or contain a harvestable crop of soybeans that can be removed to create open water.

7. Ensure the remaining crop stays standing and unmanipulated to comply with federal migratory bird regulations.

Flooding in fall

As temperatures start to cool in the fall, “When should I flood?” becomes the important question. From a waterfowl-hunting scenario, the answer likely depends on your hunting zone, nearby habitat and when you plan to hunt the most. Typically for most of Missouri, peak waterfowl numbers occur sometime in November. However, the seasons run past these peak times. In any case, flooding gradually and trying to provide the most food through­out the season is important if you’re focused on overall bird usage. Many times, when flooding areas of harvested and standing grain crops, the water level is increased too fast. There is a lot of quality food and foraging opportunities for the ducks in shallowly flooded harvested crops or weedy moist soil. If you have pumping capabilities, increase water levels incrementally to flood new acres and provide fresh forage slowly through the season.

Dewatering in spring

Just as flooding and water depth are important when looking to flood a food source you’ve stewarded all summer long, drawing that water off the next spring should be done with purpose to provide the best foraging conditions for the birds. Dewatering slowly in the spring allows aquatic insects to congregate at the receding shoreline, making optimal foraging conditions for waterfowl. These protein-packed insects are critical for setting the stage for the reproduction needed for good duck numbers the follow­ing year. Wetland pools do not need to be dry in the spring to have good conditions for another crop. Corn or other grain foods planted late in the year can provide large amounts of food for the next season. Draw down slowly, enjoy the wetland wildlife, and remember, “It’s all for the ducks!”

If you have any questions or need some tips and tricks for wetland management, feel free to reach out to This email address is being protected from spambots. You need JavaScript enabled to view it..

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