Soil physical properties in Mixed Ombrophilous Forest under passive restoration process

Abstract

The objective was to evaluate the physical properties of the soil in forest areas in secondary succession and in the process of passive restoration. The areas belong to the State University of the Midwest of Paraná, Guarapuava, Brazil. The experimental design was completely randomized, with samples at six points in each area, at depths of 0 - 0.1 m, 0.1 - 0.2 m and 0.2 - 0.3 m. The forest in secondary succession had a greater amount of organic matter, this property acts directly on the other evaluated variables. The area under passive restoration had higher values for soil density, lower total porosity at the three depths and greater resistance to soil penetration, and these results are related to the history of area use. The microporosity did not differ between the studied areas and the macroporosity presented smaller values with only difference in the layer of 0.2 - 0.3 m, due to the presence of roots and decomposition of the litter. The highest value of maximum density was in the area under passive restoration (1.23 Mg m-3), with humidity of 0.32 Mg Mg-1, already in the area of forest in secondary succession this value was 1.12 Mg m-3 and humidity of 0.45 Mg Mg-1, depending on the amount of organic matter that directly influences the reduction of the density. Soil recovery in degraded areas is a slow process, and even after ten years, it was not possible to restore the ideal physical properties in the forest under passive restoration.