Megathyrsus maximus (guinea-grass) growth and two species native trees in different environmental conditions.

Abstract

In a greenhouse experiment, aimed to verify differences in growth of Megathyrsus maximus (Jacq.) BK Simon & SWL Jacobs (guinea-grass) and two native species a pionner and non-pionner trees (Heliocarpus popayanensis Kunth and Poecilanthe parviflora Benth. respectively) at four shading levels, three fertility levels and two soil water conditions. The grass grew more in high soil fertility and lower shading, and grass biomass depend on shade level, soil fertility and water availability interactions. Also, there were more grass growth and biomass when growing with a pionner tree, that presented mortality in some pots. Heliocarpus popayanensis height depends of soil fertility - stem diameter and leaf number variations were not related to these factors. P. parviflora heigth growth depended on shading, soil fertility and water disponibility interactions. Stem diameter variations reply to soil fertility and leaf number to shading and water avaibility interactions. These results pointed to a heterogeneity in the relationship between the alien grass and native tree species.