عنوان مقاله [English]
Salinity stress limits forage productivity, and plays a major role in determining the distribution of plant species across different types of environments. Medicago polymorpha and Medicago scutelata are annual legumes species that product valuable forage and grazing material in pasture and rangelands of Iran. The objective of this study was to evaluate the effect of the salinity stress with Na 2 So4 on Forage quality of Medicago polymorpha and Medicago scutelata. The experimental design was completely randomized design with five levels of salinity stress 0, 50, 100, 150 and 250 mM with Na 2 So4 in four replications and 50 seeds per replication. Seeds were grown in plastic pots in sterile sand in greenhouse. All pots were irrigated with distilled water until germination stage. Then the pots were irrigated uniformly every other day with modified Hoagland’s nutrient solution during 40 days and finally forage quality was measured. The data were analyzed using SPSS software. The difference between the means was compared using Duncan test (P<0.05). Results showed that increasing the salinity caused significant decreases in the crude protein percentage, crude metabolism energy and dry mater digestibility percentage of M. polymorpha and M. scutelata. This study showed that the crude protein percentage, crude metabolism energy and dry mater digestibility percentage of Medicago polymorpha against salinity more than Medicago scutelata species. Increasing the salinity stress caused increases in the crude fibre and ADF of M. polymorpha and M. scutelata.