Spatial distribution of Azospirillum brasilense in 2D flow cell: Effect of irrigation and inoculation regimes

• Published in: European journal of soil science 2024-07, Vol.75 (4), p.n/a
• Main Authors: Chen, Fengxian, Ronen, Zeev, Arye, Gilboa
• Format: Article
• Language: English
• Subjects: Adsorption; Agricultural practices; Azospirillum brasilense; Bacteria; Crop production; Crop yield; Desert plants; Drip irrigation; Hydrus 2/3D; Inoculation; inoculation regime; Irrigation; Irrigation effects; Irrigation efficiency; irrigation regime; Irrigation systems; Irrigation water; Mathematical models; Nucleotide sequence; Numerical models; Physical properties; Plant growth; plant growth promoting bacteria (PGPB); Rhizosphere; Sand transport; Sandy soils; Soil; Soil bacteria; Soil microorganisms; Soil water; Spatial distribution; Surface properties; Two dimensional flow; two‐dimensional bacterial transport; Unsaturated flow; Unsaturated soils; Water flow
• ISSN: 1351-0754; 1365-2389
• DOI: 10.1111/ejss.13552

Recent advances in the use of plant growth‐promoting bacteria (PGPB) have highlighted their potential to significantly enhance crop yield and plant health. In desert areas with sandy soil, employing drip irrigation systems to inoculate PGPB serves as an efficient method that saves both time and labour. This study examined the absorption, transport and spatial distribution of two strains of Azospirillum brasilense (Sp7 and Cd) under two‐dimension (2D) unsaturated transient water flow. We used sand as a substitute for sandy soil and evaluated bacterial surface characteristics, adsorption isotherms and transport under different irrigation and inoculation regimes. The research determined that, owing to its smaller size and lower adsorption, A. brasilense Cd exhibited enhanced mobility and occupied an inoculated area 33% larger than that of A. brasilense Sp7. Moreover, subsurface drip irrigation (SSDI) exhibited a 29% higher inoculation area than surface drip irrigation (SDI). The sequence of introducing PGPB suspension and irrigation water impacted the distribution, particularly for A. brasilense Sp7. The attachment/detachment numerical model adequately described the 2D bacterial distribution (R2 ranged from 0.75 to 0.99), providing a useful tool for predicting bacterial distribution in soils and optimizing agricultural practices to enhance crop productivity. Overall, smaller bacteria, SSDI inoculation and inoculation before irrigation could enhance the extent of inoculation. This study provides novel insights into optimizing PGPB inoculation strategies in agricultural settings, highlighting the importance of considering bacterial physical properties, irrigation techniques and inoculation sequences to improve PGPB distribution within the rhizosphere. Smaller bacterial cell size, SSDI inoculation and inoculation before irrigation can enhance inoculation extent of plant growth‐promoting bacteria (PGPB) in sand.