Preconsolidation of Ultisol subjected to the traffic of agricultural tractors

Resumo

 The objective of this study was to evaluate the preconsolidation pressures and the coefficient of compressibility of the soil caused by the traffic of agricultural 4 × 2 tractors in yellow red argisol. For the uniaxial compression tests, three undisturbed 0-15 cm deep soil samples were randomly collected for the following situations: natural soil condition; after one and two wheel passes of a Valtra BM 120 4 × 2 TDA® tractor with 7100 kg total weight, with diagonal 14.4-24 R1 front tires with 82.74 kpa inflation pressure and 18.9- 24 rl rear tires with 96.53 kpa inflation pressure, with tire-ground contact areas of 0.11 and 0.13 m2, respectively, at the speed of 8 km h–1. Soil samples were subjected to the uniaxial compression at pressures ranging from 25, 50, 100, 200, 400 and 800 kpa for 30 minutes. The tractor traffic increased the preconsolidation pressure of the soil. Tractor traffic influenced soil compression, thus emphasizing the need for strict control in decision-making regarding the number of wheel passes of machinery in agricultural areas in the studied soil.