The Effect of the Nitrogen-Fixing Bacteria and Companion Red Clover on the Total Protein Content and Yield of the Grain of Spring Barley Grown in a System of Organic Agriculture

Field research was conducted in Poland from 2019–2021 to determine the effect of bacteria Azospirillumlipoferum Br17 and Azotobacter chroococcum, as well companion red clover on total protein content yield grain spring barley cultivated a system organic agriculture. Two factors were examined field experiment: I. bacterial formulations: 1—control, 2—nitrogen-fixing (Azospirillumlipoferum Br17, chroococcum), 3—nitrogen-fixing chroococcum) + phosphorus-releasing (Bacillus megaterium var. phosphaticum, Arthrobacter agilis), 4—nitrogen-fixing (Azotobacter plant growth-promoting rhizobacteria (PGPR) subtilis, Bacillus amyloliquefaciens, Pseudomonas fluorescens); II. crop: control without crop, clover, Italian ryegrass. In grain, determined calculated. The obtained study results demonstrated that growing season conditions significantly affected grain. highest recorded following an application nitrogen-fixing combined with PGPR fluorescens) grown clover.