Influence of Microbial Inoculants on Anions Behavior in Saline Soils under Moisture-stressed Conditions

Abstract

Soil salinity is a major constraint affecting agricultural productivity by disrupting nutrient balance and increasing toxic ion accumulation. Microbial inoculants offer a sustainable approach to ameliorate saline soils through biochemical transformations and anionic regulation. To evaluate the potential of salt-tolerant microbial inoculants for the biological reclamation of dry land saline soils with electrical conductivities (EC) of 4.03, 5.01, and 6.03 dS m-1 in a laboratory incubation experiment with 75 % field capacity (FC) moisture level at Tamil Nadu Agricultural University, Coimbatore, during 2021-2022 with incubation periods of 30, 60, and 90 days. The study evaluated two microbial inoculants: CSR-GROW-SURE (containing bacterial strains: Bacillus licheniformis, Lysinibacillus fusiformis, and Lysinibacillus sphaericus) and TNAU Culture (containing Bacillus subtilis) collected from CSSRI, karnal and TNAU, Coimbatore. Both microbial inoculants CSR-GROW-SURE and TNAU Culture significantly reduced bicarbonate (HCO3-) chloride (Cl⁻), and sulphate (SO42-) concentrations across all salinity levels (4.03, 5.01, and 6.03 dS m⁻¹), with percentage reduction (9.91, 7.96 and 11.53 %), (9.98,7.87 and 10.33 %) and (10.00, 7.48 and 6.45 %) respectively, observed at 90 days after incubation (DAI) and at the 3 L ha-1 dose over control. Similarly, TNAU Culture @ 3 L ha-1 showed on par with percentage decrease of (9.66, 7.61 and 10.11 %,) HCO3-; (9.71, 7.49 and 6.34 %) of Cl⁻; and (9.71, 7.46 and 6.34 %) of SO42- respectively, in 4.03, 5.01, and 6.03 dS m-1 of saline soils Compared to the control, decreases in HCO3-, Cl- and SO42- emphasizing the role of halotolerant microbes in improving soil health under dryland saline conditions.