Variation in Crop Yield Depending on the Tractor Tire Contact Area and Clay Loam Soil Moisture

As the demand for productivity increases, machines are becoming heavier, and large coverage implements cause the slippage of tractor driving wheels, which initiate soil compaction and displacement. Sources indicate that compaction has an adverse impact on crop growth and grain yield. However, heavy machinery under draft is not always to blame for yield losses. The aim of the six-year research was to establish the relationship between grain yield and the slippage of tractors on heavy clay loam soil under two different moisture conditions. The spring cereals were grown as peas, spring barley, and spring wheat. Each treatment plot was compressed from track-to-track separately, altering the tire contact area on each treatment plot. Different tire contact areas were achieved by adjusting tire pressure and adding double wheels, while simulating a constant draft. Wheeled plots with the smallest tire contact area produced 9% less crop yield, whereas wheeling with the largest tire contact area showed an 8% increase in crop yield compared to the control plot without compaction in the dependency of soil moisture. Wheeling is like rollers breaking down clay loam soil clods and slightly compacting the topsoil, helping to retain moisture, leading to increased yields.