Reclamation of saline calcareous soils using vegetative bioremediation as a potential approach

Vegetative bioremediation of saline calcareous soil (EC1:1 11.01 dS m-1) was practised through growing fodder beet (Beta Beta vulgaris var. magnum) and millet (Panicum spp.) in soil columns. Beet was grown at a planting density of 4427 plants m-2, whereas millet was grown at two planting densities: 5202 (M1) and 8928 (M2) plants m-2. Some plants were irrigated with 233 mu S cm-1 water throughout the experiment (70 days), while for others non-saline water was replaced with saline water (2.52 dS m-1) at the middle of the experiment. The control was leaching of uncropped soil. Beet had higher ash content and efficiently extracted higher amount of salts (particularly Na and Cl) along with their aboveground biomass than millet under the two irrigation regimes. Millet grown at high planting density had higher ash content and extracted higher amount of salts (particularly Cl) than those at low planting density. Bioremediation, particularly in the case of millet (M1), considerably enhanced soil hydraulic conductivity as compared with leaching treatment; thus, facilitating the removal of some soluble salts beyond the root zone. Accordingly, soil electrical conductivity was considerably decreased by 5469% compared with the untreated soil. It is concluded that mainly fodder beet is a potential candidate for efficient bioremediation of saline calcareous soils.