Produtividade e comportamento de Ilex paraguariensis A.St.-Hil. (Erva-mate) sob dois regimes de manejo em Floresta Ombrófila Mista

Abstract

The present study was developed in the Municipality of Turvo, PR, where the extractivism of yerba mate is a traditional activity. Two neighboring areas of 1.8 and 1.64 hectares were divided into 400m2 sample units. The areas are in silvopastoral and forest management in secondary succession, respectively. In the sample units were identified and the CAP was measured for all trees with CAP equal to or greater than 5cm. This measurement was carried out in the years of 2012 and 2015. The location of the 3702 individuals measured in relation to the southwest vertex of each of the areas was also noted. The spatial distribution of Ilex paraguariensis individuals, the diametric structure and the density were evaluated, with significant differences between the two areas in the diametric structure and density. In secondary succession the species occupies the sixth place in the sociological position, whereas in the silvipastoral system it is in the first position. Phenology was evaluated leaf sprouting and fall, flowering, fruiting and absence of phenological phase. Fruiting and leaf fall in females did not show significant differences between the two areas. All other phases presented higher intensity and longer period of occurrence in the silvipastoral system. In both areas the leaf fall showed correlation only with the minimum temperature. In the evaluation of the abiotic variables that influence productivity, only the silvopastoral system was evaluated because there was no harvest in the secondary succession in the studied period. 23 sample units were evaluated for chemical characterization of soil and incidence of light. Principal component analysis was performed to evaluate which variables are related to leaf weight at harvest and to increment in basal area (IBA). The weight had a negative correlation with the percentage of aluminum in the soil (M%) and positive correlation with pH, calcium content and photosynthetic active radiation. The silvopastoral management carried out in the study area increases the production and favors the development of I. paraguariensis, to the detriment of the other native species.