Efetividade da inoculação com Bradyrhizobium spp. em amendoim cultivado em solo da Zona da Mata de Pernambuco

Abstract

Peanut (Arachis hypogaea L.) Is legume used in the world with a high percentage of comestible oil and protein and in Brazil is cropped in different soil and climatic conditions. Due to its adaptability to tropical conditions and with high economic value peanut is very important for typically small, family based properties involved in food production in the Northeastern Brazilian. With the objective to evaluate the effectiveness of peanut inoculation with selected strains of Bradyrhizobium spp. bacteria it was carried out a field experiment in not irrigated conditions, in a soil located at the Itapirema Experimental Station (IPA), tropical rainforest zone of Pernambuco state. The experiment was conducted in a factorial 2 x10, in randomized block design, with four replicates. Were used two peanut cultivars (BR 1 and BRS Havana) comparing 8 peanut strains, including the controls treatments with N fertilization as ammonium sulphate (200 kg N ha-1) and without nitrogen fertilizers. In the periods of flowering and grain maturity plants were collected (6 per plot) for evaluation of nitrogen fixation (dry nodules biomass, dry plant biomass, total N in shoots and relative efficiency of strains). At the final of the experiment were determined the following components of plant productivity: dry biomass of 100 grains(g); dry biomass of 100 pods (g); grain and pod yields (kg ha-1). Nitrogen fertilization increased dry biomass and total N accumulation in shoots in the period of grain maturation (p≤ 0,05). The relative efficiency of the strains was greater on cultivar BRS Havana. Bradyrhizobium spp. inoculation showed no significant difference (p≤0,05) to the others treatments in reference to dry biomass of nodules. It was not observed significant difference between treatments on grain and pod yields. In the soil used the rhizobia native from soil was so effective than rhizobia applied by inoculation and they supply nitrogen to attend the N demand by peanut cropped inthe used Brazilian rainforest soil.