Evaluation of the halophyte Salsola soda as an alternative crop for saline soils high in selenium and boron

Urbanization, industrial development, and intensive agriculture have caused soil contamination and land degradation in many areas of the world. Salinization is one important factor contributing to land degradation and it affects agricultural production and environmental quality. When salinization is combined with soil pollution by trace elements, as it occurs in many arid and semi-arid regions around the world, strategies to phyto-manage pollutants and sustain crop production need to be implemented. In this study, we present the case of saline soils in the West side of Central California which contain naturally-occurring selenium (Se), boron (B), and other salts, such as NaCl, CaCl₂, Na₂SO₄, and Na₂SeO₄. To sustain crop production on Se- and B-laden arid saline soils, we investigated the potential of the halophyte "agretti" (Salsola soda L.) as an alternative crop. The aim of our greenhouse study was to examine adaptability, B tolerance, and Se accumulation by S.soda grown on soils collected from a typical saline-laden field site located on the West side of the San Joaquin Valley (SJV). Our results showed that S.soda tolerates the saline (EC ~ 10 dS m^-1) and B-laden soils (10 mg BL^-1) of the SJV even with the additional irrigation of saline and B rich water (EC ~ 3 dS m^-1 and 4 mg B L^-1). Under these growing conditions, the plant can accumulate high concentrations of Na (80 g Na kg^-1 DW), B (100 mg B kg^-1 DW), and Se (3-4 mg Se kg^-1 DW) without showing toxicity symptoms. Hence, S. soda showed promising potential as a plant species that can be grown in B-laden saline soils and accumulate and potentially manage excessive soluble Se and B in soil.