If one of your biggest, heaviest machines just popped into your head, you’re right. Combine. Grain cart. 4WD tractor. But why even ask this question? Because it pays to fight compaction, and you want to tackle your biggest causes of soil compaction first. After all, soil compaction squashes your yields and inflates your fuel bill. And that’s just the beginning of its impact on your farm.

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Today’s Farms Have a Big Weight Problem

Soil specialists will tell you that any axle load over 10 tons is going to damage your soil. Problem is, with most powered farm machinery today, a 10-ton-per-axle load is somewhere in the welterweight category. 

Axle load examples table
Chart adapted from “Practices for Mitigating Soil Compaction” presentation by Jodi De-Jong Hughes and University of Minnesota Extension.

A class 9 combine with a 400-bushel tank can easily tip the scales at 20 tons per axle. A 1,200-bushel grain cart puts down a porky 40 tons per axle. And that’s not even a big grain cart these days. Axle load alone determines how deeply compaction will push its way into your subsoil.

But contact pressure determines how badly compaction affects your topsoil. (Contact pressure is the amount of pressure exerted by the tire on the soil.) And this is where you have a chance to counter compaction’s profit-robbing effects.

Why You Can’t Afford to Ignore Compaction

It’s not reasonable to expect farm machinery to shrink any time soon. More acres to harvest and more weather headaches equal less time for fieldwork. So strategies to limit compaction in your fields are key. Why does it pay to fight compaction? 

Compaction Lowers Your Yields

When high contact pressure presses the soil tightly together, it’s hard for plants to reach their full potential. And when your plants are falling short, your yields are too. 

  • Stunted roots
  • Late emergence
  • Reduced nutrient uptake
  • Oxygen starvation
Compacion squeezees plant and root growth graphic

Compaction Raises Your Operating Costs

Dense or muddy soil makes equipment pull harder and wear out faster and can prevent your nitrogen and other nutrients from reaching your plants. In other words—you spend more and accomplish less.  

  • Increased fuel use
  • Increased input costs
  • Increased maintenance costs
  • Increased drying costs from uneven emergence

Compaction Endangers Your Farm’s Long-Term Outlook

The destruction of healthy  soil structure will affect this year’s yields. And yields far into the future too.

  • Loss of fertile topsoil through runoff and erosion
  • Fewer beneficial microorganisms in the soil
  • Reduced drainage 
  • Increased risk of drought in marginally dry years

Read More: Farmers in North Dakota and Minnesota may lose $587 million over two years for every 10% of compacted land.

Compaction Steals Your Profits Again and Again.

In perfect growing conditions, you might not notice much of a yield hit from compaction. But any time you add other stresses—dry weather, wet weather, pests—the effects of compaction will rear their ugly heads and deliver a hit to your yields.

In this study, compaction caused a 30% yield hit in year one. By year 4, the corn yield had completely recovered and actually surpassed the yield at the beginning of the study. But notice how in years 7, 9, and 12 you see yield hits once again? 1988 was extremely dry at the testing location, and 1990 and 1993 were wet years.

Your #1 Strategy to Fight Compaction: Get Your Tire Pressures as Low as Possible in the Field.

As we mentioned above, your heaviest pieces of equipment are the best place to begin tackling compaction problems on your farm because they can cause the most damage. But a farm’s largest equipment also has a farm’s largest tires . . . doesn’t that solve the problem? Yes, big tires help. But in order for your farm to have a fighting chance against compaction, you have to pay close attention to the air pressure in your tires.

Lower Tire Pressures = Less Compaction + Higher Fuel Economy

As the air pressure drops in a tire, the sidewalls deflect and cause the tire’s footprint to grow longer. And that’s what you’re after: long, even footprints. This can have a huge impact on your operation. Not only do bigger footprints fight compaction, they solve other problems too: When your tires have more surface area in contact with the ground, you have more lugs on the ground, which means increased traction and decreased slip. And this translates to faster working speeds and better fuel economy.  Who doesn’t want to save time and fuel in the field? 

There are a few ways to figure out the proper tire pressures for your equipment: 

  1. The manufacturer databook published by your tire brands.
  2. Your tire brands’ online tire pressure calculators: We’ve gathered a list of online tire pressure calculators for your convenience.
  3. You can call NTS Tire Supply and speak with a tire expert for help in optimizing the tire pressure on your equipment.

Do tracks offer lower ground pressure? 

Yes and no. The numbers on paper and the real life realities of the tracks vs. tires debate are two different things. A radial tire exerts pressure on the soil at about 1–2 psi above its inflation pressure. For example, a tire inflated to 10 psi will exert 11–12 pound per square inch of pressure on the soil. 

To find the ground pressure of a track, you would multiply its length by its width and then divide the weight the track has to carry by this number. Using this method, a track can be down in the 4–5 psi range in terms of ground pressure. This is better, right? The problem with tracks is that the midrollers create pressure points beneath the track—areas of pressure that are dramatically higher than the overall average ground pressure. Plus, a track has a longer dwell time because of its long footprint. In wet field conditions, this gives the track more time to cause soil damage as it rolls through the field. Still, tracks hold some advantages over tires that tip the balance in their favor with many farmers. 

Mount Larger Tires to Fight Compaction

We always recommend that tire pressures on your large equipment (4WD tractors, etc.) should be 15 psi or lower in the field. Sometimes, this isn’t possible with original equipment tire setups. One way to achieve a lower field tire pressure is to mount larger tires—either wider, taller, or both. At NTS Tire Supply, we specialize in tire changeovers—or the process of upgrading a farm vehicle’s tires to a different size to reduce compaction and improve traction, flotation, and fuel economy. If your machine’s current tires are struggling in these areas, it pays to give us a call and speak to a tire expert about a new level of performance for your machine.

A central tire inflation system (CTIS) on your planter can help reduce pinch row compaction and reclaim lost yield.

Use IF/VF Technology to Drop Your Tire Pressures Lower

In addition to mounting larger tires, you can also upgrade to IF- or VF-rated radials. First pioneered by Michelin in the early 2000s, IF (increased flexion) and VF (very increased flexion) radials put more tire—a larger footprint—on the ground thanks to lower air pressures and super flexible sidewalls. As we’ve mentioned above, any time you gain more footprint in any given tire size, you’re decreasing your tires’ contact pressure and slamming the brakes on yield-robbing compaction. By definition: 

  • IF radials can carry the same load as a standard radial at 20% less pressure.
  • VF radials can carry the same load as a standard radial at 40% less pressure.
  • Or, you can increase their maximum loads by 20% or 40% above a standard radial’s limits.

Learn More: How IF- and VF-rated radial tires can help you roll to bigger yields.

Use a Central Tire Inflation System to Optimize Your Tire Investment

Since you have to set your tire pressures for specific loads and speeds to maximize the benefit of IF/VF technology, you may end up making frequent adjustments. And let’s be honest: Time is always an issue during the busy seasons. If you’re crunched for time, will you be able to spend the precious minutes needed to readjust your tire pressures? 

A central tire inflation system makes pressure adjustments easier and more effective. For example, you can set a higher pressure for high-speed road travel and then—with the touch of a button—drop your tires to their minimum safe pressures for maximum flotation and traction in the field. No more compromise air pressures that jeopardize tire longevity on the road and performance in the field.

Read More: Michelin shares details on how CTIS works.

Installing a central tire inflation system (CTIS) on your tractor can increase traction by up to 20% and lower fuel consumption by 10% while extending tire life by 20%.

Don’t Let Big Equipment Squash Your Yields

Without tire setups optimized to reduce soil compaction, your farm is losing productivity: Yields, fuel efficiency, and time. And don’t forget the long-term consequences of compaction either, from increased fertilizer costs to soil erosion.  Your heaviest pieces of equipment are the best place to begin tackling compaction problems on your farm because they can cause the most damage. Will a tire pressure adjustment fix the problem? Do you need wider or taller tires? NTS Tire Supply is here to help Drive Your Farm Forward. Talk to one of our traction experts and start growing with bigger yields and greater efficiency.

June 20, 2022
Knowledge Guide


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