DEFORMATION OF SILTY LOAM SOIL UNDER THE TRACTOR TYRE

The influence of up to 10 successive tractor wheel passes on the vertical deformation of the soil under the tractor tyre was studied under field conditions. The vertical residual and elastic soil deformations were measured using sensors consisting of two parallel plates which are inserted into the soil profile. This method allows sensor positioning without violation of soil structure and remote measurement. The vertical residual soil deformation increased with the number of wheelings. Its highest values occurred at a depth of 15-25 cm and decreased in deeper layers. The magnitude of the soil deformation and its maximum depth were greater when the wheeling was applied at a higher soil moisture content. The vertical elastic deformation increased with the number of wheelings and decreased after successive static loadings.