The effect of selenium biofortification in alfalfa (Medicago sativa)

Biofortification of agricultural productions is important to enhance the quality of the products. The aims of this research were to investigate the possibility of selenium biofortification of alfalfa in the calcareous and non-calcareous soils by applying fertilizers differently (control, soil application, inoculant of seleno-bacteria, foliar application, combined soil, and foliar applications of selenate). Morpho-physiological properties and nutritional responses, such as shoot dry weight, phosphorus, potassium, selenium, zinc, and iron concentration in the plant's tissue were measured. In all parameters, the use of selenium sources in the calcareous soils had a significant effect compared with the control treatment. Among the methods and sources of selenium, foliar application of sodium selenate gave the best response. By the usage of this treatment, Se concentration was increased up to 112.5% and 182%, respectively, compared with the control treatment in non-calcareous and calcareous soil. According to the results, inoculant of selenium bacteria and sodium selenate are recommended as a natural way to selenium biofortification in alfalfa and to improve the quality of the produced forage. In addition, attention to the biological potential of the soil and the use of native soil bacteria is also recommended.