SOIL PHYSICAL PROPERTIES AS AFFECTED BY TRAFHC: SINGLE, DUAL, AND FLOTATION TIRES

ABSTRACT Soil compaction from field traffic is a world-wide concern in production agriculture. Soils may be especially vulnerable to excessive compaction during early spring tillage operations when the necessities of timely planting often demand decisions to traffic fields at highly susceptible moisture contents. It is necessary to quantify the soil response to typical spring traffic loading to better understand the potential for adverse effects on crop response. For this reason, a 116 kW front-wheel-assist tractor, ballasted to a 6.4 t rear axle load, was operated on deep- tilled and moldboard plowed silt loam soil conditions using three rear tire configurations: single 18.4R42** radials, dual 18.4R42** radials and single 66 x 43.00-25 high-flotation tires. Soil physical properties measured to a depth of 500 mm showed no significant changes due to axle load effects below 250-300 mm. Single and dual tires affected physical properties to a greater depth than did flotation tires on plowed soil. However, the 6.4 t axle load did not produce excessive soil compaction compared to the effect of a 27.8 t vehicle.