Combination effects of microbial inoculation and N fertilization on maize yield: A field study from southern Brazil

The use of inoculants based on diazotrophic microorganisms is an alternative to decrease the dosage and increase the efficiency of nitrogen fertilizers, especially in grains that are demanding and nutrient-responsive crops. Cyanobacteria is photosynthetic and nitrogen fixing prokaryote; however, there has been little focus on Anabaena cylindrica and Nostoc muscorum as biofertilizers in the presence of added nitrogen sources. The purpose of this study was to explore the maize yield in two crop seasons in Londrina, Brazil under different nitrogen rates (topdress, 0-130 kg ha-1; sowing, 20-150 kg ha-1) and microbial inoculants (A. cylindrica, N. muscorum and Azospirillum brasilense), in randomized block design with factorial arrangement 4 x 4. Different phytometric characteristics (e.g. height of plant and spike insertion; stem diameter; area idex and chlorophyll content of leaf; Nitrogen (N), Phosphorous (P) and Potassium (K) contents in leaf) and grain yield (such as quantity of rows ear-1, grains row- 1, grains ear-1, ear plant-1, grain N content, weight 1000 grains-1, grain yield) were evaluated. The phytometric characteristics and maize yield were not altered by the interaction between N rates and inoculants, demonstrating that N rates do not interfere with cyanobacteria performance. The inoculation with A. cylindrica favored the development and yield performance of maize and resulted in an increase in grain biomass of 912 kg ha-1 (20.46%) in the crop season 1 and 1020 kg ha-1 (21.11%) in season 2 crop, related to the control. The use of above inoculants was favorable in the responses of maize growth and yield components, particularly when combined with an adequate dose of N. The results demonstrated the potential of microbial inoculants in the improvement of maize crop yield.

Automated summary

The use of inoculants based on diazotrophic microorganisms can decrease nitrogen fertilizer dosage and increase efficiency, especially for demanding crops. This study demonstrated the positive effects of inoculating Anabaena cylindrica and Nostoc muscorum on maize yield, and the enhanced performance when combined with an appropriate dose of nitrogen.