Diversidade da comunidade de plantas invasoras em sistemas agroflorestais com café em Turrialba, Costa Rica

Abstract

The objective of this work was to evaluate the floristic composition of spontaneous species in coffee (Coffea arabica L.) cultivated in full sun and in agroforestry systems, under organic and conventional management.Twenty treatments were evaluated in a randomized complete block design, in a split plot in time, with three replicates. In July 2002 and September 2005 a spontaneous species survey was carried out. Richness, abundance, diversity and evenness index were determined. Reductions were observed in richness, abundance, diversity, and evenness values, and the smallest ones were found in high conventional treatment. In both seasons, the highest percentages of points with bare soil were found in the high conventional treatment, while the lowest percentages were found in all treatments under medium and low organic management, and in three out of the seven treatments under medium conventional management. These results demonstrate that in treatments where herbicides are frequently applied, the presence of trees does not prevent the soil from being exposed.