Resumo

GUTIERREZ-RODRIGUEZ, Francisco et al. Compaction induced by breaking of agricultural tractors in vertisol. Terra Latinoam [online]. 2012, vol.30, n.1, pp.1-7. ISSN 2395-8030.

The level of induced compaction in crop fields is strongly influenced by the traffic of tractors and agricultural machinery. In most cases, soil compaction increases the mechanical resistance of the soil and thus prevents water infiltration and root growth; it also generates changes in bulk density and decreased porosity. The objective of this study was to test the degree of impairment of some physical properties in a clay soil. A randomized complete block design with three replications in a split-split-plot arrangement was employed. We used three tractors of different masses, powers, and drive train, and four variants of counterweights and tire air inflation. F values for the various tractors were significant at 5 and 1%. In the comparison of means between tractors (Factor A), the tractor TM (universal tractor medium 4 × 4), the more compacted soil was in the top two layers, because of the wear caused by the tires and the value of cone index was above the TP (heavy tractor 4 × 4). The compaction behavior variables ballast and tire inflation (Factor B) had its highest value in the upper layer, while in the two lower layers of soil it depended on the gravimetric moisture content. Moreover, soil bulk density was affected by most of the cases relative to the control.

Palavras-chave : penetration resistance; bulk density; multi-tillage.