Microbial augmentation of salt-affected soils: Emphasis on haloalkalitolerant PGPR

Abstract

Food availability is set to be the biggest problem facing humanity over the next 50 years and beyond as the global population is estimated to increase steadily along with escalation in degradation rate of crop lands. Alkalization and salinization of soils have become widespread global issues and have been identified as crucial factors for limiting agricultural crop productivity. Various parameters have been described to characterize salinity and alkalinity of the soils and elucidate its effect on plant growth. This chapter further overviews how conventional physicochemical technologies are ineffective to repair SAS. Hence, a sustainable alternative is to utilize bespoke microbial species with desirable attributes so that salt-affected problem soils could be made suitable for cultivation of agricultural crops. It highlights biological nitrogen fixation (BNF) as well as other desirable plant growth-promoting (PGP) traits such as phytohormone secretion, ACC deaminase activity, solubilization of minerals, and exopolysaccharide production by free-living diazotrophic microbes from alkaline and saline soils and further describes the role of haloalkalitolerant plant growth-promoting rhizobacteria (PGPR) to recoup alkaline saline soils for sustainable mode of agriculture and conservation of environmental quality.