Widen the window with fall fertilization

Compacted springs are begin­ning to feel like the new normal. Cold, wet weather often gives way just in time to allow a quick win­dow for critical spring operations. 

Applying fertilizer in the fall allows more of that window to be used for fieldwork and planting. Plus, fall fertiliz­er applications free up strained infrastructure, allowing more time to stage dry fertilizer and anhydrous ammonia. Additionally, fertilizer prices are often more attractive in the fall.

Typically, anhydrous ammonia is thought of as the problem in logistical bottlenecks. The loss of a pipeline and increased difficulty in securing rail transport have exacer­bated that situation. Few things are more frustrating than watching the planter sit while you wait for tanks or product to fill those tanks. Ap­plying nitrogen in the fall can help alleviate this stress. Some growers are not comfortable with putting all their nitrogen on in the fall, but there are ways to manage those concerns.

One popular strategy is to put one-half to two-thirds of a corn crop’s anticipated nitrogen needs down in the fall with a plan to side-dress or top-dress additional nitrogen during the growing season. This allows planting to start when conditions are favorable, even if spring ammonia supplies are tight. It also allows the final rate to be adjusted in-season based on growing conditions and what kind of weather has occurred since the fall application.

MFA’s Nutri-Track N nitrogen-modeling program can be used to determine how much additional N is needed and can even create a variable-rate applica­tion prescription for applying it. Of course, a stabilizer is still recommend­ed to hold nitrogen in the ammonium form longer.

Dry fertilizer can also be an ob­stacle in the spring. Larger tenders and high-capacity custom-appli­cation trucks create situations in which product leaves fertilizer plants as quickly as it comes in. Ex­ternal factors such as river flooding affect barge traffic and the ability to unload product, tightening these supply situations. Fall application takes pressure off the system, your operation and you. Phosphorus and potassium applied in the fall along with sulfur and zinc will be ready to go to work for you in the spring, and you won’t need to wait when spring weather doesn’t cooperate.

Another management strategy growing in popularity is to fertilize in front of beans, and fall is a good time to do that as well. Growers em­ploying MFA’s Nutri-Track program often apply two years’ worth of fertilizer in front of corn to supply that crop and the following soybean crop. Two-year applications are an­other way to help navigate logistical strains and increase efficiency. In recent years, however, yields have generally exceeded the applied fer­tilizer rates. In some instances, rates applied in front of the corn crop simply need to be increased, but an­other way to address this is to make up the difference in front of the soybean crop. Rather than applying increased rates of fertilizer that as­sume two large crops, growers can maintain their existing program but apply a flat rate of plant nutrients to help make up the difference after harvesting a larger-than-expected corn crop. A flat-rate rig or buggy can be used because soil variability has already been addressed with variable-rate application in front of the corn.

Often overlooked is the impor­tance of fall fertilizer for pastures and hay fields. Phosphorus, potassi­um and even some nitrogen applied in the fall help pastures repair damage incurred during summer grazing and haying and replace nutrients that were removed. Fall fertilizer encourages a denser stand and helps plants get ready for win­ter. A well-fertilized stand will also compete better with weeds and be ready to go in the spring when wet conditions do not allow fertilizer applications at green-up. Growers raising alfalfa should always plan to apply half of that crop’s nutrient removal in the fall. This allows for efficient use of potassium and prepares the crown and roots for winter.

Talk to your local MFA personnel about other strategies you can em­ploy to make fall fertilizer applica­tions work for you.