Physical properties of a Brazilian sandy loam soil after the traffic of a military vehicle M113 BR

ABSTRACT Soil physical properties can be changed after vehicle traffic, especially by heavy military tracked vehicles. The Santa Maria military Instruction Field, where the experiment was carried out, is currently the most used area for armored tracked vehicles training in Brazil, with the M113 BR being the main equipment. The aim of this study was to determine the effect of the straight line and pivoted traffic intensity of the M113 BR on the physical properties and advancement of the compaction state of an Abruptic Alisol (Argissolo Vermelho-Amarelo Ta Distrófico abrúptico) with military vehicle traffic history. The study was conducted in a completely randomized design, independently evaluating the effect of straight and pivoting traffic in three soil layers (0.00-0.04, 0.10-0.14, and 0.20-0.24 m). For the straight-line traffic, traffic intensities (TI) with one (TI1), two (TI2), and five (TI5) passes on the same trail were evaluated. For the pivoting traffic, TI with one (TI1P) and two (TI2P) pivots was evaluated. Both studies had two non-traffic treatments (NT). The soil bulk density, total porosity, macroporosity, microporosity, saturated soil hydraulic conductivity, soil penetration resistance, soil bearing capacity, preconsolidation pressure, and gravimetric water content were analyzed in this study. In the straight-line traffic, cases with no significant differences in TP, Ma, Mi, and Ks prevailed. The highest TP, smallest Bd and largest Mi were observed in the 0.10-0.14 m layer. In the pivoting traffic, one pass was sufficient to increase Bd and decrease TP, Ma, Mi, and Ks in the 0.00-0.04 m layer and the increase from one to two pivotings had a significant difference only in Mi in this same layer. Both types of traffic intensity did not affect the PR in any layer. The Abruptic Alisol, pre-compacted from long-term military training, supported the loads applied by the M113 BR when additional traffic occurred in straight line mode, but not when in pivoting mode. The preconsolidation pressure parameter was not appropriate to assess the ability of the soil to support loads applied by pivoting traffic.