Impact of Gypsum and Bio-Priming of Maize Grains on Soil Properties, Physiological Attributes and Yield under Saline–Sodic Soil Conditions

In order to enhance soil qualities and boost crop output, gypsum, plant-growth-promoting rhizobacteria (PGPR), and chitosan are all viable solutions. This study’s goal was to find out how different amounts of chitosan—0, 25, 50, 75, and 100 mg L−1—in combination with gypsum and PGPR inoculation (Azospirillum lipoferum + Bacillus subtilis), affected the yield of maize plants growing in saline–sodic soil. Field tests were carried out in triplicate across two growing seasons, 2020 and 2021, using a split plot design. According to the findings, applying the gypsum + PGPR + 50 mg L−1 chitosan treatment (T8) considerably improved plant physiology (chlorophyll, carotenoids, and proline levels), nutrient indicators (N, K+ and K+/Na+ ratio), soil enzyme activity (dehydrogenase, urease, amylase, and invertase), cation exchange capacity (CEC), and porosity. On the other hand, we revealed positive effects on Na+, bulk density (BD), electrical conductivity (EC), and the proportion of exchangeable sodium (ESP), thus, enhancing the productivity compared to the alternative treatment. Therefore, it might be inferred that using gypsum, microbial inoculation, and 50 mg L−1 chitosan may be a key strategy for reducing the detrimental effects of salinity on maize plants.