Comparison of Bulk Density Beneath a Belt Track and Tire

Wheel traffic is considered a major cause of soil compaction in production agriculture. Soil compaction depends on initial conditions, load, contact area and tire type and shape at the soil surface. The use of tractors equipped with tracks instead of tires has the potential of reducing soil compaction because of reduced surface contact pressure and difference in load distribution over a relatively long-narrow track. The introduction of a new agricultural tractor equipped with a rubber belt track permits a crawler tractor to compete with a large four-wheel drive tractor in both speed and mobility. Soil bulk density was measured as an indication of compaction which results from trafficking with a rubber belt track tractor and a four-wheel drive tractor. The measurements were taken on three tillage treatments at three soil water contents. Most of the comparative differences in bulk density resulting from trafficking with the two tractors were non-significant at the 0.10 level. Bulk densities at the deeper depths were significantly higher for the tire than the rubber belt track for some tillage treatments. However, in all comparisons, bulk density resulting from the rubber belt track was numerically less than from the tire