Invest in P and K instead of Fe this fall

Written by Davin Harms on .

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).