Insumos e indicadores biológicos em agrossistemas com bananeiras

Abstract

Studies were performed in the experimental area of Embrapa Agrobiologia, region - RJ, in order to evaluate the association of arbuscular mycorrhizal fungi (AMF) with a variety of banana “Grand nine ", and the potential antagonist in AMF biocontrol nematodes. We also tested biological indicators and products as alternatives to monitoring and restoration of ecosystems with bananas. The first study evaluated the microbial activity in soil samples from two management systems with bananas in the municipality of Casimiro de Abreu, RJ. In the second study, was evaluated the AGAS organic product for the control of nematodes in banana. In the third, was evaluated the potential antagonist in AMF biocontrol nematode Radophulus similis and their contribution in the development of banana plants in the greenhouse. In the fourth study was estimated the effect of using two management systems with bananas in the community of soil fauna in Casimiro de Abreu, RJ. The indices of diversity, richness and density of macrofauna groups was calculate in each system. The results indicated no significant differences between management systems in relation to carbon and nitrogen levels of microbial biomass and soil organic carbon ratio vs. carbon microbial biomass in each season, while the variables soil basal respiration and metabolic quotient indicated that the organic farming system was greater efficiency of microbial biomass and the use of substrate by soil microorganisms than the system with conventional tillage. The organic product AGAS showed significant difference in population of the nematode Meloidogyne spp. and Radophulus similis both in samples of roots after 60 days of treated. In the field was control to phytoparasitic R. similis with the AGAS treatment showing a decrease in soil at 120 days. In the laboratory tests were performed with R. similis and the results demonstrated that the effects of exposure of nematodes to organic product showed a high percentage of control, especially in higher dosages with a 100% with respect to the nematicide effect in Radophulus. Regarding the development of plants in treatments with species of arbuscular mycorrhizal fungi inoculated in banana no significant difference. The foliar phosphorus analyzed varied significantly in the treatment with the fungus Scutellospora calospora, and foliar calcium and magnesium for the treatments with fungi: S. calospora, Entrhopospora colombiana and S. calospora + Glomus clarum. AMF reduced the population of the nematode R. similis in roots of banana plants in a greenhouse, and S. calospora and G. clarum were the most efficient. In soil macrofauna results indicated a reduction in the banana organic system, with lower density and lower richness of taxonomic groups when compared with the conventional system. The group of decomposers and predators showed better soil quality in organic farming system especially in the summer due to its greater diversity and density at this season of year.