Evaluation of soil structural quality in mechanized harvesting (harvester and forwarder) of Eucalyptus grandis.

Machine traffic intensity in the wood harvesting is variable along the field (area), with negative effects on the soil physical parameters. In this context, the aim was to evaluate the structural soil quality in harvester and forwarder traffic trail of Eucalyptus grandis harvesting. The study was carried out in Paraná, in Dystrophic Red Latosol (Oxisol), frank sandy clay. The physical parameters evaluated were: soil bulk density (DS), total porosity (PT), and soil penetration resistance (RSP), with 0.35 kg kg of gravimetric moisture. By means of transects, with three replicates, the data were obtained at distances 25, 75, 125, and 175 m of the machines traffic trail, corresponding to one pass of the harvester, and then 20, 16, 10, and 6 from the forwarder, respectively, until 0.60 m depth soil. In order to compare the distances effects, DS and PT values, obtained only in the rows line, were analyzed by the t-multiple test (α = 0.05), while RSP obtained in seven transverse points at the traffic trail, was evaluated in the soil cross section by geostatistical analysis, with the GS+ software. The highest machine traffic intensities at distances of 25 and 75 m resulted in greatest changes in the structural soil quality until to the deeper layers (0.60 m), while at other distances, changes were up to 0.40 m deep. These results indicate need for differentiated soil preparation where there is greater traffic intensity.