On-farm demonstrations show tire pressure is a key factor in preventing soil compaction


Nearly 100 farmers and ag professionals gathered at Roche Farms on August 8 for an equipment, compaction and soil health event organized by Dodge County Farmers for Healthy Soil and Healthy Water. Several university educators from Minnesota and Wisconsin taught farmers the effects compaction has on soil health.

Jodi DeJong-Hughes, University of Minnesota-Extension regional educator and Francisco Arriaga, UW-Madison Associate Soil Science professor, began the meeting identifying myths about soil compaction and factors affecting compaction. Farmers learned how management practices, most importantly checking the PSI of their tires and considering how many axles are distributing the equipment weight, can impact soil health. Arriaga focused on soil aggregation, pore size distribution, and its importance in soil health. When there isn’t correct pore size distribution yields can decrease by up to 60%.

Jake Kraayenbrink, owner of Agribrink, shared how he went from being a pig farmer in Canada to the founder and developer of an inflations/deflation tire system sold globally. He discussed how factoring tractor speed and equipment weight; they could set the correct tire pressure to lower the impact of compaction. He also shared that because equipment has gotten gradually 900 pounds heavier each year since 1960, the increased weight has led to decreases in soil health. He emphasized that setting the correct tire pressure will help save the soil.

Farmers had the opportunity to walk the fields for insightful demonstrations to see the effects of compaction under the soil profile. Kraayenbrink and DeJong-Hughes led discussions in a lasagna pit. The difference from a traditional soil pit and a lasagna pit is that it’s four feet deep of layered sand and topsoil. Once the pit is layered, David Roche backed over one side of the pit with a tanker with a tire pressure of 33 PSI and the other side with 10 PSI. The impressions on the soil pit were 7.5 inches deep and 4.5 inches deep, respectively. Once the pit was dug open, everyone could see how far the pressure went down. This provided an easy to understand visual of how compaction is affecting farm fields.

Another field demonstration led by Arriaga was a buried pressure bulb test to demonstrate the difference between a tire and track combine. He set up two sites using 12-inch-deep trenches with hoses filled with liquid. This set a level for farmers to watch to see if the water went up when the equipment drove over the trench. Using this demonstration, he can measure the pressure the equipment puts on the ground, increasing the risk for soil compaction.

Brain Luck, UW-Madison associate professor and extension specialist, presented a demonstration using pressure mats. The pressure mats show that a contact map patch grew in size when tire pressure decreased. This relates to soil compaction because there is less pressure on the soil when there is a larger footprint. He expressed its importance to find the optimal tire pressure where farmers can successfully work in the fields while minimizing soil compaction impact.

View the videos below to see the demonstrations and to learn more about the impacts of soil compaction.

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