Residual phosphate fertilization and Azospirillum brasilense in the common bean in succession to maize intercropped with Marandu grass

Abstract

One of the alternatives for achieving sustainable agriculture and a reduction in production costs, especially with
phosphate fertilisers, is to inoculate seeds with bacteria of the genus Azospirillum. The aim of this study therefore, was to evaluate
residual phosphate fertilisation and Azospirillum brasilense, together with the contribution of straw from maize intercropped
with Marandu grass, on leaf nutritional content, yield components and winter bean yield. The experiment was carried out on the
Teaching and Research Farm, of the School of Engineering at UNESP, located in Selvíria in the State of Mato Grosso do Sul, in a
typic clayey dystrophic Red Latosol. The experimental design was of randomised blocks with four replications in a 5 x 2 factorial
scheme. The treatments consisted of beans sown on straw from maize intercropped with Marandu grass on areas that had received
five levels of P2O5
in the form of MAP, applied during an initial cultivation of black oats (0, 30, 60, 120 and 240 kg ha-1), both with
and without inoculation of the oat and maize which preceded the beans with Azospirillum brasilense. Leaf nutrient content, leaf
chlorophyll index (ICF), yield components and bean productivity were all evaluated. Inoculation with Azospirillum brasilense of
the black oat and maize seeds improved the nutritional status of the plants, but had a negative effect on grain yield. Fertilisation of
the oat crop with phosphorus had a positive residual effect on the beans, with increases in yield components and grain yield.