Harvest is underway in some parts of the country, and will soon begin for others. And while some regions are experiencing warm, dry conditions that are ideal for resolving severe compaction, if the opposite is true in your area and conditions are wet, there’s a risk that running heavy harvesting equipment will result in soil compaction.
Considering compaction can cost you 5-10% in yield, according to research from Ohio State University Extension, it’s a good idea to avoid it when possible. Here are some tips for doing so.
1. Use flotation tires or tracks to reduce surface compaction. Penn State Extension soil scientist Sjoerd Duiker says tires inflated to 100 psi, or iron wheels, cause high contact pressures and can result in surface compaction — which is compaction less than 1 foot deep. In no-till, he adds, yield losses from surface compaction can be quite dramatic the following year.
But don’t turn to tillage to remedy surface compaction. Research from University of Kentucky found that long-term no-till soils will recuperate from most surface compaction within a year due to higher levels of biological activity.
2. Reduce your axle load. Compaction that occurs greater than 1 foot deep is considered subsoil compaction, Duiker says, and it’s caused by axle load. If you go over wet soil with an axle load of 10 tons or higher, you’re likely causing subsoil compaction below 20 inches, he says.
This type of compaction is one to avoid, because research has shown that freeze-thaw and wet-dry cycles don’t remove it, and subsoilers don’t usually go that deep. (Even if they could, they wouldn’t be able to completely alleviate it, Duiker says.) He adds that research has shown a 5% yield decrease due to subsoil compaction that lasted longer than 10 years.
3. Check for ruts. If you’re worried your equipment may be causing too much compaction, scout your fields to see if there are ruts. Paul Jasa, ag engineer for University of Nebraska Extension, says if the combine and grain carts aren’t leaving ruts, don’t worry about compaction from the equipment. If a rut wasn’t formed, there was enough soil structure present to support the weight without causing additional compaction, he says.
4. Adopt controlled traffic. The first pass of tires causes 80-85% of soil compaction, Jasa says. So if additional passes are made on the same traffic lines, little additional compaction occurs.
While it will take some planning and maybe some equipment changes to implement a controlled traffic system, no-tillers who adopt the practice are seeing paybacks. Participants in Controlled Traffic Farming Alberta have seen 10% yield increases in some field areas where controlled traffic was used.
In an article from 2009, Iowa no-tiller Clay Mitchell claimed his machinery exerted 40% less effort on controlled traffic lanes. For more information on controlled traffic, check out our recent special report, “Blazing a Path to Profitability with Controlled Traffic Farming.”
What are you doing to ensure compaction doesn’t occur this fall? Tell us what you would add to this list in the comments below.