Perspectives of Bio-Organic Fertilizer for Growth Promotion of Sorghum and Maize Under Variably Irrigated Field Conditions

Abstract

The ability of specific plant growth-promoting rhizobacteria (PGPR) to alleviate biotic and abiotic pressures on crop productivity is largely attributed to their ACC-deaminase activity. This research investigated how the inoculation of Pseudomonas fluorescens and the application of rock phosphate-enriched organic fertilizer (OF) influenced the development of maize and sorghum during periods of drought. To simulate moisture stress, irrigation was withheld during vital growth phases. Experimental treatments included 2, 3, and 5 irrigation cycles for sorghum, and 3 and 5 cycles for maize, using the 5-irrigation setup as the ideal moisture baseline. Data showed that for plants treated exclusively with synthetic fertilizers (uninoculated), growth plummeted as water availability decreased. Conversely, the introduction of P. fluorescens significantly offset the growth inhibition caused by water scarcity. The synergy between PGPR and OF emerged as the most successful strategy for enhancing biomass in both crops, particularly when irrigation was limited to only 2 or 3 applications. Remarkably, inoculated plants subjected to water stress exhibited superior growth performance compared to well-watered (5 irrigations) plants that lacked microbial inoculation.