Desenvolvimento e componentes de rendimento de milho inoculado com azospirillum brasilense e fertilizado com água residuária de suinocultura e fertilizante mineral

Abstract

In order to increase agricultural yield and nutrient uptake by plants, diazotrophs as fixing N bacteria from atmospheric air have been used as inoculum for seed treatment since they also promote plant growth. However, the beneficial uses of diazotrophs in agriculture rely on complex interactions, including the sort of fertilizer used. Swine wastewater has been used as biofertilizer to reduce production costs and to be applied on soil in order to recycle nutrients. There are not studies which evaluate the interaction between nutrient source and diazotrophs inoculation concerning maize cropping. In this context, the aim of this study was to evaluate the effects of inoculum Azospirillum brasilense associated with swine wastewater applied as biofertilizer on the initial development, yield components and corn seeds quality in 2013/2014 and 2014/2015 cropping years. Three bio-fertilizer application rates were used (corresponding to 0, 30 and 60 kg ha-1 nitrogen doses, respectively) and mineral fertilization at the same doses, with and without inoculum, totaling ten treatments, with four replications each. In the greenhouse, it was observed that there was a decrease when Azospirillum brasilense was inoculated at germination term, but an increase on emergence speed, lateral root growth and some shortening of main roots in maize seedlings. In the field, it was observed that the interaction between the biofertilizer and A. brasilense increased yield components, productivity, and it was beneficial to seed germination and vigor of the produced maize seeds. The most significant results were shown at 60 kg ha-1 nitrogen dose for both mineral fertilizer and swine wastewater, in both studied seasons. Thus, the use of biofertilizers from swine wastewater associated with A. brasilense use was an alternative to reduce corn production costs in relation to nitrogen fertilization.