Soil Inoculation by Azospirillum Affects Protein and Carbohydrate of Maize Grain under Nitrogen Deficiency

The use of nitrogen-fixing bacteria as an alternate N resource would play an important role in environmental protection by providing an eco-friendly and cost-effective inputs for farmers. The present investigation was carried out in the experimental field of Agric. Res. Stat. of Fac. of Agric., Cairo Univ., Giza, Egypt in 2014 and 2015 seasons. The primary objective of this investigation was to study the effect of Azospirillum bacteria on maize yield as well as grain protein and carbohydrate. Six maize cultivars were evaluated under three N treatments namely, high-N (286 kg N /ha), Low-N (without applying N) and BNF (bacterial nitrogen fixation, 24 kg/ha of bacterial inoculum) using a split-plot design with three replications. The investigation indicated that BNF treatment significantly surpassed Low-N treatment by 7.11% for grain yield/ha and 19.56% for protein yield/ha. The most interesting observation in the study was the superiority of BNF treatment for grain protein percentage by 4.0% and 16.91% over High-N and Low-N treatments, respectively. The present investigation concluded that maize yield as well as grain quality could be improved under low soil-N conditions by using Azospirillum bacteria not only for N fixation but also by excretion of phytohormones such as auxins and cytokinins and proved that Azospirillum bacteria could be used as an alternate N resource to maintain a clean environment as well as maintain soil fertility and sustainability.