The Impact of Bio-fertilizers and Nitrogen Fertilizer on Barley Yield Productivity and Quality

Abstract

Biofertilizers present a viable strategy for decreasing dependence on chemical fertilizers in agriculture while mitigating their environmental and health impacts. These biofertilizers are composed of beneficial microorganisms that enhance plant growth through processes such as phosphate solubilization and nitrogen fixation. The objective of this study was to characterize bacterial isolates from the wheat rhizosphere and assess their potential as agents for promoting plant growth. The isolates were evaluated for their ability to solubilize phosphate, produce indole, and generate ammonia. Molecular identification through 16S rRNA gene sequencing revealed two effective strains: Enterobacter cloacae and Pantoea agglomerans. A field experiment was conducted at the Malawi Agricultural Research Station (Minya Governorate) over two agricultural seasons, 2022/2023 and 2023/2024, using the Egyptian barley cultivar Giza 138 to assess the effectiveness of these plant growth-promoting rhizobacteria (PGPR) when applied either individually or in combination, alongside three levels of nitrogen nitrogen fertilizer (15, 30, and 45 kg N/fed⁻¹) on their agrophysiological characteristics and grain quality. The results indicated that the combined application of Enterobacter cloacae and Pantoea agglomerans at a nitrogen level of 30 kg N/fed⁻¹ significantly enhanced barley performance, resulting in the highest grain yield, increased 1000-grain weight,  longer spike length, a greater number of grains per spike, and improved chlorophyll a and b, as well as protein content. These findings illustrate that co-inoculation with these PGPR strains, coupled with a reduced quantity of chemical nitrogen fertilizer, can significantly  enhance barley yield and quality, providing a sustainable alternative to traditional fertilization methods.