Avaliação de cultivares de feijoeiro em sistema orgânico de produção na Baixada Fluminense, RJ

Abstract

Production of common bean (Phaseolus vulgaris L.) under organic production systems may improve the economic return of farmers, even in small cultivated areas, due to the high market value of the product, besides eliminating the use of agrochemicals which contributes to environmental preservation. The adoption of organic systems for bean production requires the identification of cultivars better adapted to this management. With the objective of assessing biomass production, nodulation and yield of different bean cultivars in organic production system, a field experiment was conducted in the Integrated Agroecological Production of 47 km, in Seropédica-RJ. Sixteen bean cultivars were evaluated, covering different grain commercial types, in randomized blocks design with four replications, between May and August 2011 in Planosol. The seeds were inoculated with rhizobium commercial inoculant for bean, and 6 Mg ha-1 of cow manure was applied at planting and 1 Mg ha-1 of castor seed meal was applied at cover. Biomass was sampled at two growth stages, at flowering and 14 days after, and grain yield and yield components were assessed at the end of the cycle. Differences among bean cultivars were found for shoot dry mass at stages of flowering and early pod filling. Nodulation of bean plants was intense, particularly at flowering. Comparing the averages of all cultivars, biomass and N accumulation in shoots increased between the two sampling times, but in this period nodule mass and number decreased, indicating a process of nodule senescence during reproductive stages. The average grain yield was 192 g m-2, with a variation from 153 to 258 g m-2 among cultivars, with the largest yield of the cultivar Aporé. The most productive cultivars showed higher number of pods per plant and number of grains per pod. The cultivars Aporé, BRS Radiante, Campeiro, BRS Pontal, Bolinha and BRS Vereda yielded more than 2000 kg ha-1. The evaluated cultivars showed good performance under the organic system production in the Rio de Janeiro Metropolitan Lowland.