Improving maize sustainability with partial replacement of N fertilizers by inoculation with <i>Azospirillum brasilense</i>

Abstract Maize ( Zea mays L.) is a major cereal crop worldwide and demands N fertilizers, which can be replaced partially by plant growth‐promoting bacteria. In Brazil, inoculants carrying Azospirillum brasilense strains Ab‐V5 Ab‐V6 have exponentially grown, but quantitative study on the replacement of fertilizer still missing. Under greenhouse conditions, we investigated effects A. cells metabolites applied via seeds or leaf‐sprayed at V3 growth stage roots confirmed strong benefits in traits that improve uptake water nutrients. field, 30 trials were performed 13 sites Brazil over 10 yr, comparing noninoculated inoculated maize receiving 0, 50, 75, 100% (90 kg ha –1 N) (urea) as side‐dress 35 d after emergence. Overall, inoculation significantly increased grain yield 3.1%. Increases lower higher levels, subtropical tropical clayey sandy soils, with low soil organic carbon levels. Yield increases due to statistically significant all levels fertilizer, except for 50%. Inoculation supply 75% 4.6% compared counterpart and, noteworthy, did not differ from non‐inoculated control N. These results feasibility replacing 25% N‐fertilizer seed , besides possibility avoiding emission 4.95 million Mg CO 2 ‐e per year.