Comunidade nativa de rizóbios e sua interação com estirpes selecionadas como inoculantes para leguminosas no Maranhão

Abstract

The state of Maranhão is located in the humid tropic region, is characterized by nitrogen deficiency in the soil. Most legume species are able to fix nitrogen through symbiosis with rhizobia. Nitrogen fixed by legumes is largely trapped in the litter, incorporated into soil organic matter, and increased in grain yield. The objective of this research was to evaluate the symbiotic efficiency of inoculants recommended by the Ministry of Agriculture, Livestock and Supply (MAPA) and native rhizobia for legumes with potential use in agroforestry systems and production in Maranhão. The legumes studied were: Gliricidia (Gliricidia sepium (Jacq.) Steud.) and Sombrero (Clitoria fairchildiana R.A. Howard) and Cowpea (Vigna unguiculata). The experiment for tree legumes was conducted in a completely randomized design - DIC, 2x3 factorial scheme, 2 different areas and 3 treatments (1 - inoculation with rhizobia strains recommended by MAPA, SEMIA 6168 and BR 8007; 2 - treatment with nitrogen chemical fertilization ( 60 kg / ha of N in the form of urea); 3 - control) for each legume species, with four replications each. The cowpea experiment was randomized blocks with four treatments (1-inoculation with strain SEMIA 6462; 2-inoculation with strain SEMIA 6464; 3- fertilization with 60 kg / ha of N; 4-control) and 5 replications. The inoculant strains recommended by MAPA for the evaluated legumes, except for the shade, showed low efficiency compared to the control treatment in Pedro do Rosário (MA) soils. The nodulation in cowpea (Vigna unguiculata (L.) Walp.) culture responded positively to inoculation with strain SEMIA 6464 and SEMIA 6462, in soil of São Luís - MA and provided better vegetative development of the plant and increase in yield parameters, which resulted positively. in the competition of strains against the native soil community. The sombrero used relatively efficiently with the inoculated treatment, such as cowpea, which responds positively with the companies as recommendations recommended by MAPA