Dispersão endozoocórica de sementes de arroz daninho (Oryza sativa L.) e capim-arroz (Echinochloa crusgalli L.) por bovinos

Abstract

The objective of this study was to evaluate endozoochory dispersal, recuperation and germination of weedy rice (Oryza sativa L.) and barnyard grass (Echinochloa crusgalli L.) seeds passed through the digestive system of cattle. The experiment was divided into two phases: first, the daily seed recuperation rate was determined after passing through the digestive system of six steers. It was dosed individually 1000 weedy rice seeds and 13818 barnyard grass seeds for each animal, and these seeds were subsequently collected in the feces. In the second phase, it was determined seed germination and emergence rate passing or not passing through the digestive system of cattle in two types of substrates (fecal plaque or soil) in a 2x2 factorial design. The seed recuperation in feces showed sigmoid behavior with maximum recovery on the second day after dosage. The recuperation of the species in the feces was 50.9% and 23.4% for weedy rice and barnyard grass, respectively, which shows that both have potential endozoochory dispersal. However, the seed germination of these species reduced after they passed through the digestive system, and in the fecal plaque they presented inferior emergence in comparison to the soil. The quarantine period for animals that ingest weedy rice and barnyard grass seeds should be at least 6 and 7 days, respectively.