Potential contribution of Sulla spinosissima (L.) and Sulla pallida (Desf.) as a forage crop for arid pastures rehabilitation

Abstract Mediterranean climate is reported to harbor a wide range of forage legume species. However, little information is available on the potential use of these forages as fodder. We, therefore, conducted a study to evaluate the chemical composition, mineral content, and in vitro dry and organic matter digestibility of two forage legume species from arid pastures located in the Northeast of Morocco: Sulla spinosissima subsp. capitata and Sulla pallida Desf. To our knowledge, this is the first report about the nutritive value of these two species. Our results showed a wide variation between selected Sulla species; the phenological stage had a significant effect (p < 0.05) on most evaluated chemical traits and digestibility parameters. Comparatively, Sulla spinosissima L. had higher organic matter digestibility (72.43%OM) at the vegetative stage in correlation with lower acid detergent fiber (ADF) (24.23%DM), lower condensed tannin, (CT) (0.27%DM), and higher crude protein (24.01%DM). Conversely, Sulla pallida Desf. plants with a considerable amount of ADF (40.34%DM) and CT (4.50 %DM) had lower organic matter digestibility (56.09%OM). Both species are mineral-rich and contain satisfactory mean (gram per Kilogram Dry Matter) levels of calcium: 23.25 in Sulla spinosissima L. and 13.75 in Sulla pallida Desf.; phosphorus 1.01 in Sulla spinosissima L. and 1.53 in Sulla pallida Desf. The results of the present study suggest the suitability of both Sulla species for domestication to enhance pasture productivity and to ensure animal nutrition of small ruminants in arid pastures of Mediterranean area.