Compactação e recalque superficial de um latossolo vermelho em condição de campo e laboratório

Abstract

The agricultural tractor is considered the main source of power for the realization of the mechanized operations essential to the production process of a culture. However, the application of dynamic loads in the soil, produces stress in wheel/soil interface in surface and depth. These stresses can compress different soil layers. The aim of this study was to evaluate the compaction and superficial settlement of an Oxisol under different traffic levels in field conditions; and propose a methodology for dynamic loads test, from traffic of the pneumatic wheel, applicable in the laboratory. In the field we used an agricultural tractor and in laboratory a traffic simulator. In two experiments we adopted the design of randomized blocks in split plots consisted of ten treatments with four replicates per treatment, totaling forty experimental units. The plots consisted of two tire inflation pressure: 96.5 and 137.9 kPa, and the subplots were five traffic intensities: zero (control), one, two, four and eight passes of the tractor or wheel simulator, according to the experiment. The variables measured were soil dry density, degree of compaction and superficial settlement. The first two variables were analyzed at the depth of 0-0.10 m. All variables were obtained after the traffic on two conditions: field and laboratory. At traffic simulator were used undisturbed soil samples collected in the field and in regions where had no tractor traffic. These samples were subjected the values of contact pressure near to those determined for the tractor in field conditions. The results showed that the variables used were able to characterize changes in the state of compaction of the soil in question. For both experimental conditions there was no significant influence of tire inflation pressure nor the interaction between pressure and traffic. The variables studied suffered significant influence only the traffic. The joint analysis (grouping) of the experiments showed that no have significant difference between experimental conditions. Thus, the traffic simulator was capable of reproducing the compaction induced by the tractor.