INFLUÊNCIA DA FORMA E POSIÇÃO DA ENCOSTA NAS CARACTERÍSTICAS DO SOLO E NA REGENERAÇÃO NATURAL EM ÁREAS DE PASTAGEM ABANDONADAS1

Abstract

The aim of this work was to evaluate the influence of the topographic conditions on soil chemical and physico-hydric characteristics and on the natural regeneration of abandoned pasture areas. We studied eight areas of hill lands in the municipality Itaboraí - Rio de Janeiro State. Two topossequences were selected in each one of the areas. These topossequences were divided into shoulder, backslope and footslope positions contemplating the main landform, concave and convex. Two experimental plots (20 x 10 m) were installed in each section of the toposequence, one for each landform, for the evaluation of soil chemical and physical-hydric characteristics, natural regeneration and pasture biomass (stocked biomass and regrowth rate). Our results show that soil texture was influenced by landscape position, in which the shoulder had lower clay content. The chemical characteristics were not influenced by topographic conditions. The physico-hydric characteristics were influenced by the particle size of the soil. The natural regeneration presented few species, and was not influencied by its position in the landscape and by the landform. However, the development of natural regeneration tended to be more limited in pasture dominated by Urochloa humidicola (Rendle) Morrone e Zuloaga.