Allelopathic Effect of the Coffee Residue in Emergency and <i>Urochloa brizantha</i> Growth

Abstract

Weed management is important for the increase of agricultural crops, since they have a negative influence on yield and harvest quality. To optimize the management it is possible to use the coffee infusion residues, which ha s caffeine contents, a substance that has an allelopathic effect to some plants. Thus, the goal was to evaluate the allelopathic effect of coffee residues in the emergence and growth of Urochloa b rizantha under product doses, gathering and application seasons in pre - and post - emergence. The experiment was carried out at UFLA, in a greenhouse with potting, with Urochloa b rizantha seeds, cultivar Piata , in DBC with three replicates in the factorial (3 × 4 × 2): time of gathering (A, B, C); concentration of ground (0, 20, 50 and 100 (% W/V)) and pre - and post-emergence application. The height, fresh and dry weight, Emergence Speed Index—ESI and phytotoxicity were evaluated. It was verified the significance for pre-emergence treatments, reducing plant height, increasing phytotoxicity and reducing fresh weight. For the ESI, it was identified that only for gathering season obtained a significant result. In the phytotoxicity evaluations, it obtained interaction for the season of application with residue gathering season . For product doses and applications in pre - an d post-emergence interaction was observed for phytotoxicity. It is concluded that the residue has allelopathic effect reducing growth and increasing phyto toxicity up to a maximum dose of 55.83 and 86.76 for pre - an d post-emergence applications of Urochloa b rizantha .