Potencial de espécies locais na diversificação dos agroecossistemas, como culturas de cobertura, no manejo de plantas espontâneas

Abstract

The management of weeds is complex and comprises a major component of the production cost of most cultures. Growing cover crops is one of the forms of management to reduce weeds competing. Agrobiodiversity, including the biota and the surrounding properties, constituting a cultural and natural capital able to provide ecosystem services. In this context, we developed a study to investigate the potential of wild species Crotalaria incana (rattlesnake rattle or Xique-Xique) and Diodia saponariifolia (Poaia the swamp), which occur in a nearby landscape the Atlantic Forest fragments in the River Basin region Guapi-Macacu-RJ, as part of sustainable agro-ecosystems, constituting strategy to reduce the use of herbicides and enhancing local biodiversity. This potential was assessed in C. incana through phenological studies of plant height, crown diameter, number of branches, presence of inflorescence and number of pods along the cycle and at different times, October, January, February and March. Also evaluated in its interaction with the climate and planting dates. It was found that the planting October C. incana had the longest growing season, low seed production. In the planting in February, the performance of C. incana was good in both parameters; while planting in March, C. incana demonstrated lower performance for mass production and seeds. Preliminary assessments of total biomass and macronutrients, indicate the potential of C. incana as a cover crop that needs to be better investigated. As for D. saponariifolia, a creeping species characterized as macrophyte, evaluations were made of soil coverage percentage after its introduction, compared to the most frequently dominant families in the system, Poaceae and Cyperaceae. Subsequently evaluated the seed bank behavior in this same area after being introduced (experimental area), compared to natural area, which was already established spontaneously. We observed a cooling populations of Poaceae and Cyperaceae after the introduction D. saponariifolia. The spontaneous seed bank revealed a reduction in the expression of these families, important competitors in the system. Possible allelopathic effect of D. saponariifolia in suppressing spontaneous, was evaluated by bioassay with the soil of the natural area where D. saponariifolia prevails spontaneously. In this ground sesame seeds were germinated Sesame indicu L. () in 15-cell trays 3 treatments (T1, T2, T3). T1, activated carbon was added to neutralize allelopathic effects harmful to the development of seedlings. T2, do not add anything. In T3 (control) used a soil adjacent area without the presence of individuals D. saponariifolia. There was no significant difference in the development of seedlings in 3 treatments, indicating no evidence of allelopathic effects of D. saponariifolia on Sesame germination. We can infer that the suppression of processes D. saponariifolia are only for "muffling".