ReachOut: The Road To Compaction Is Paved With Good Intentions


By Mike Zwingman

By Mike Zwingman

Compaction is exactly what it sounds like: compression of your soil. Take a handful of your soil in your hand, then squeeze. See how the same amount of soil takes up less space? That’s compaction. Know why it takes up less space? Because you squeezed the space out of it.

This, friends, is a bigger deal than it might seem. Soil is composed of two main components: matter and the space between. Ridding your soil of its space removes one half of its essential ingredients. Take a moment to consider some other of your favorite duos minus one ingredient: Peanut butter, no jelly. Biscuits, no gravy. Batman, no Robin. Tango, no Cash. Not nearly as good as the complete originals, right?

Ridding your soil of space causes a host of unwanted changes. Because what fills the space (when it is there) is air and water. No space means a lack of air, and a lack of air causes changes in the microbial population of your soil, which, as I’ve discussed in a previous article, disrupts the processing of extremely important organic material and throws the balance of nutrients off kilter. Since there is no air taking up space in your soil, your soil is also more dense, which causes issues with its water holding capacity and infiltration rate. Dense soil also inhibits root growth, which means only bad things for your plants: reduced water and nutrient uptake, flopping, reduced yield, etc.

I hope that you agree that compaction sounds undesirable at best, downright ugly at worst. Yet, odds are high that your fields are suffering compaction. Why? How?

Because the road to compaction is paved with good intentions.

You till your field to make the ground friendlier to seeds, but tilling gets top bill for causing compaction. You don’t follow the same wheel tracks to increase your efficiency, but not following the same wheel tracks? It’s causing compaction. You use row equipment because you’re a grower and you get the job done, but row equipment is always the culprit in sidewall compaction. Basically, the machines that are helping you do what you do are also causing your problems—they are heavy, which compresses the soil, and they scrape and push space out of your soil as they scrape and push through your fields.

Q: So what’s a grower to do? A: Sell your equipment.

Kidding. Don’t sell your equipment.

What you can do: Don’t work in fields that are too wet. Wet soil is more prone to compaction than drier soil, so weigh conditions carefully before you venture in and remember not to be a slave to calendar conventions. Do use the same wheel tracks. Do take extra care of your machinery. Your equipment is already designed to minimize compaction, so help it along by maintaining proper air pressure in the tires. Do consider rotating your crops as root growth through the soil can help alleviate some compaction issues, and changing your crops will change the depth that roots reach.

A little mindfulness here can save you a lot of compaction there. It is much easier to prevent compaction than to cure it, but what about damage that’s already been done? This answer is much slower and more expensive than you want to hear, but if you suspect that you have problems with compaction in your fields, even the slow, expensive answer is worth it. Vertical tillage.

Take a ripper to 1/3 of your fields each year. Rotate annually, so that in three years, every compacted inch of soil has been vertically tilled. Repeat. When you’re not ripping, practice prevention. And truly, rotate your cover crops. A crop of tillage radishes is cheaper and less painful than any time spent ripping.

If I could wave a magic wand and solve one problem for all growers, it would be compaction. If I could wave a magic wand and convince you all to care especially about one issue, it would be compaction. But I don’t have a magic wand. All I have is this humble blog, which I hope has been helpful.

Plant carefully, friends.

Up next: We continue on the road to soil health with an article on goals.