Mineral fertilization and rock biofertilizer with <i>Bradyrhizobium</i> and mycorrhizal fungi on cowpea

Abstract

The objective of this study was to verify the performance of mineral fertilizers (NPK) compared with rock biofertilizers with mycorrhizal fungi (AMF) and rhizobia on the productivity of dry biomass of nodules and shoots of cowpea (Vigna unguiculata L. Walp). There was carried a experiment with two sources of nutrients: mineral fertilizers and biofertilizer (BPK) from phosphate rock and potash rock. The mineral fertilizer was applied in the level recommended for the culture; and the biofertilizer was applied in three rates (one, one and half and two times the recommended rate). The species Glomus etunicatum and Gigaspora albida were applied individually, and added a treatment without AMF. The levels of rhizobia was Bradyrhizobium inoculation with mixture of strains NFB 700 e BR 3267 and the treatment without inoculation. Rock biofertilizer application increased dry nodules and shoots biomass, and N fertilization decreased nodulation. Mycorrhizal fungi did not affect nodulation and shoot dry matter of cowpea, while the Bradyrhizobium inoculation and biofertilizer were effective in shoot biomass when using the rock biofertilizer in highest level.