Depth of emergence and interference of Sporobolus indicus L. in coexistence with forages

Abstract

A large percentage of Brazilian pastures are degraded by weeds, and grasses are the most difficult to manage because they are morphologically, physiologically, and biochemically similar to forage species. In addition, they form a large seed bank in the soil, with a predominance of dormant seeds, causing economic losses to livestock. Studies on the density of Sporobolus indicus L. coexisting with forage plants in pastures and on its ideal germination depth, in different soil textures and coverage, are important to guide the producer to perform its control and assist in the development of management with greater efficiency. Therefore, the objective was to determine the depth of emergence of S. indicus and evaluate the performance of forage species Urochloa brizantha cv. Marandu and Arachis pintoi, living with increasing densities of the weed, aiming to determine the critical density. The two experiments will be conducted in an area next to the Weed Laboratory - LAPDA, at FCAV-UNESP. In the first experiment, S. indicus will be sown in containers at different depths, with daily evaluations of emergence and, at the end, of dry mass accumulation. In the second, S. indicus, U. brizantha, and A. pintoi will be previously sown in trays and, later, the seedlings will be transplanted into pots coexisting with increasing densities of S. indicus; grass height, length of the dominant legume branch, and chlorophyll content of both will be evaluated. The design in both experiments will be a randomized block design with four repetitions. The data obtained in both experiments will be submitted to variance analysis using the F test and, if significant, the Tukey test will be performed (p>0.05). (AU)