Weed Seed Bank on Integrated Crop-Livestock System with Eucalypts in Subtropical Brazil.

Weed seed bank on integrated crop-livestock system with eucalypts in subtropical Brazil Abstract This study aimed to analyze more than four years effect of eucalyptus growth on the weed seed bank spatial distribution, functional traits abundance and botanic composition on integrated crop-livestock system in Subtropical Brazil. Soil sampling (0-20cm) was done in five positions between Eucalyptus dunnii double rows [(4x3)x20m]. The experiment was a randomized block design with five replications and five distances between hedgerow trees. The method used for seeds quantification and identification in soil was the seedling emergence in pots inside the greenhouse. The weed phytosociological indices, functional traits abundance and seed densities (m-2) of monocots and dicots, families and species were evaluated. 17 families and 49 species of weeds were found. The indices contribution that make up the families and species relative importance was different in positions between tree tracks. For functional traits, the life cycle type and seed form differed between those positions. Four years effect of eucalyptus growth changed the composition and size of weed seed bank, differently for functional traits, families and species, by modifying their importance and abundance in relation to the distance from arboreal component. Index terms: alley cropping, fitossociology, integrated weed management, abundance, agroforestry, functional traits