Effects of bacterial seed inoculation on microbiological soil status and maize grain yield

Abstract

Rhizosphere microorganisms are essential for plant growth and development. Many factors, including environmental conditions, genotype, seed inoculation with plant growth promoting rhizobacteria (PGPR) and plant growth stages, influence rhizosphere microbiology. In this study, the dynamics of nitrogen and microbiological soil status at different growth stages of two maize hybrids, as well as their grain yield were analyzed, under the influence of seed inoculation with inoculant containing Azotobacter chroococum, Azotobacter vinelandii, Bacillus megaterium, and Bacillus licheniformis on during three experimental years. Higher nitrogen amount (NA), total number of microorganisms (TNM), number of azotobacters (NAZ), number of aminoheterotrophs (NAM), total number of sporogenic bacteria (NS), number of actinomycetes (NAC), number of oligotrophic (NO) and grain yield, as well as lower number of fungi (NF) were obtained under favorable environmental conditions. The hybrid NS 6010 had higher values of NA, TNM, NAZ, NAM, NO, and grain yield than hybrid Dijamant 6. What is more, higher NA, TNM, NAZ, NAM, NO, and grain yield were obtained under inoculation treatment, demonstrating that the microorganisms improve maize production and microbial abundance in the rhizosphere. The highest TNM, NAM, NF and NO were determined at stage 6-7 leaves, while the highest NA and NAC were at silking stage and NAZ at wax ripeness stage. Accordingly, hybrid choice and seed inoculation could serve as a good management practice for an increase in maize grain yield, and improved microbial population and nitrogen amount in the rhizosphere.