ONTARIO GRAIN FARMER AGRONOMY 22 Built on trust. Strengthened through generations. Your mutual partner—here for what matters most. The Commonwell. Find a Local Broker at thecommonwell.ca/find-a-broker individuals. together. PRESSURE DRIVES COMPACTION The main event at Rutherford compaction day was, as ever, the equipment demonstration, and some of the counterintuitive information it produced. With sensors placed at depths of six, 12, and 20 inches, one of Johnson and Stewart’s main messages was “tire pressure drives soil compaction.” Other factors, such as an implement’s weight distribution and tire design, also play a role, even in smaller equipment. Sensor data reiterated that even small, seemingly harmless vehicles, such as trucks or autonomous implements, can cause surprisingly high pressure spikes—particularly if their tires are over-inflated. “A real change in mindset” is ongoing, Johnson says, where more farmers are recognizing that a tire that looks a little flat in the field is actually a good thing. Johnsons and Stewart also noted that the presence of organic matter can prevent the most serious compaction from occurring in topsoil. The subsoil of the Brookston clay demonstration field appeared to be at greater risk due to its finer texture – something they say is concerning, as compaction remediation is harder to perform the further down compaction occurs. Stewart says operators should think of soil as a structure under stress from above. Even if low-PSI tires spare the top layer from the worst pressure, the subsoil is still bearing the weight of the implement, equivalent to the lower structures of a building or bridge. Whether the equipment answer to compaction prevention is tracks, more tires, or tires with more surface area, both hosts reiterate that there are always trade-offs. What is certain is that unnecessarily high pressure from above can often be avoided. • Smooth faces of the soil structure in the B horizon.
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