Compactação do solo causada por dois sistemas de colheita de madeira em florestas Eucalyptus grandis

Abstract

This study aimed an assessment of soil compaction caused by machinery timber harvest under two systems of harvesting forest Eucalyptus grandis. The study was conducted in a forest company, located in the municipality of Telemachus Borba, PR, with the following harvest systems of short logs and whole trees in soil classified as Ferralsol or Oxisol with sandy clay loam texture. We evaluated the physical parameters of the soil density, total porosity and penetration resistance. Sampling was done systematically covering an area for each harvest system and undisturbed soil samples collected along the tracks extraction, classes of distances 0-50, 51-100, 101-150 and 151-200 me the layers of 0 to 10, 10 to 20, 20 to 40 and 40 to 60 cm. With the values held normality test and for comparison test was used DMS Fisher, at 95% probability. We also conducted the mapping isolines by kriging method. In short log system, traffic machine caused significant changes in physical properties compared to the condition before traffic machines. When evaluating the compression along the track extraction operations conducted after harvest timber, it was noted that the effects of soil behaved similarly over the first two field soil layers with increasing depth in the distances 0-50 and 51-100 m, where there was more traffic. This spatial variability of soil compaction was visible in thematic maps constructed by means of geostatistical techniques in all parameters evaluated. In the system of whole trees, changes in soil after traffic machinery were also evident. In the region near the field boundary, in which there were maneuvers and Skidder traffic processor, the physical condition of the soil was deteriored because all physical parameters evaluated showed critical values of soil resistance to penetration to a depth of 60 cm. The variability of the compression along the path of extraction, in general, the classes differ away from 0 to 50 and 51 to 100 m, which was higher traffic intensity as compared to the center of the area. With the thematic maps produced was possible to see that the region near the edge of the field was the most compacted after timber harvesting operations due to more traffic on this site. Thus, there was a spatial variability of soil compaction produced by timber harvest activity in both harvest systems, being more intense in the region near the edge of the field. This information can be used to support the planning of soil preparation company in according to compaction intensity aiming to reduce production costs.