When a piece of farm equipment rolls off a dealer’s lot, the tire pressure is often set at the manufacturer’s recommended PSI. Many farmers set and forget tire pressure on machines, resulting in compaction, lower yields, and lost opportunity for optimization.
The Impacts of Tire Pressure
Tire pressure on ag equipment has a surprising impact on outcomes on the farm. From flotation and compaction to lifespan of the tire, air pressure plays a unique role.
As air pressure decreases, a tire’s footprint increases; picture a piece of equipment sinking lower and lower as tire pressure is released. At the same time, the tire’s surface area is expanding in width and length—increasing contact surface area with the ground.
The size of a tire’s footprint has an impact on so many different farming factors below.
Flotation is the degree to which tires “float” over a soil surface, especially loose or moist soil. Flotation is often tied directly to footprint size—all things equal, the larger the footprint, the more flotation. Increased footprint and flotation also help the tires (and therefore the equipment) stay atop the soil and avoid getting stuck.
The biggest benefit of increased flotation is decreased compaction.
Increased footprints and flotation essentially decrease the downward pressure on the ground, meaning there’s reduced soil compaction compared to tires with a smaller footprint and less flotation.
Compaction impacts crops in several ways:
Impeding root growth by causing resistance
Reducing the depth of water absorption, decreasing water and oxygen levels around the roots
Decreasing soil aeration, which negatively impacts nitrogen levels
All of these compaction results can decrease yield.
The impact of compaction on yield varies based on geography, soil type, weather, and more. Recent field tests from Iowa State University found: “Soil farmed with equipment exerting a maximum of 6-psi surface pressure yielded nine more bushels of corn per acre than soil farmed with more conventional equipment exerting 16-psi surface pressure.”
The downstream effects of tire pressure really can impact farmers’ bottom lines.
Effects of Tire Pressure on Different Soils
Soil type is one of the primary factors in evaluating the effects of compaction. The soil makeup determines how much moisture is capable of being held and how much potential there is for compaction.
For example, black loamy soil is comprised of clay, silt, and sand. It tends to retain water and is ideal for many crop types, including vegetables, oilseeds, wheat, and more. This type of soil is highly compactable, and yields can be drastically impacted by reducing compaction through a larger tire footprint and more flotation. Tire pressure changes have more noticeable consequences on fields with black loamy soil.
On the other hand, sandy soil is not very compactable. Water and air can't move freely in the tiny pores spaces. Adjusting tire pressure to reduce compaction will have lesser effects on this type of soil.
The Right Tire Pressure for Your Application
Now that you know the benefits of adjustments to tire pressure on your equipment, how do you determine the right level for your application?
Each tire manufacturer includes recommended PSI ranges in their documentation, and many have them available online. Some, like Firestone and Michelin, have calculators to show the recommended tire pressure based on the machine, load, tire type, and more.
Your dealer is another excellent resource for help with tire pressure decisions. And you or your dealer can ask one of AXON's Solution Consultants, and we can help understand your specific circumstances and make a calculation.
Let’s Talk Tire Pressure
There are many factors to consider when you’re determining what tire pressure is right for your equipment, field, and crops. We don’t expect you to become an expert in what tire pressure to use in which applications—AXON Tire has the experts to help you.
Talk to your dealer, and reach out to us if you think an adjustment in tire pressure could benefit you, and we’ll talk it through.