Germination, floristic composition and phytosociology of the weed seed bank in rice interropped with corn fields

Abstract

Germination, floristic composition and phytosociology in the soil weed seed bank are important to know the weed flora and to predict weed infestations. The objective of this research was to assess and to compare germination, the weed flora and phytosociology of the soil weed seed bank in rice intercropped with corn fields in Maranhão State, northeastern Brazil by the germination method in the greenhouse and by weed sampling in the field. Phytosociological parameters computed were frequency, density, abundance and the importance value of each species. Diversity was assessed by the Shannon’s Diversity Index. We recorded a total of 1,998 individuals from 40 species, 31 genera and 16 families from which 1,339 individuals germinated in the greenhouse and 659 in the field. Weed density was higher in the greenhouse (878 plants m-2) than in the field (261 plants m-2). The Cyperaceae family had the highest floristic richness with 12 species. The dominant species based on the importance value were Scleria lithosperma (IV = 37.0%) in the greenhouse and Lindernia crustacea (IV = 27.7%) in the field. Floristic diversity was higher in the greenhouse with H’ = 2.66. These results could help to predict weed infestation potential and could lead to improved weed management practices in rice intercropped with corn fields in Maranhão State.