Potential of wild annual legumes for mountain pasture restoration at two silvopastoral sites in southern Spain: promising species and soil-improvement techniques

This study evaluates the potential for pasture improvement and restoration at two silvopastoral sites. We used a total of 16 wild legume species under different management systems (rhizobial inoculation, mycorrhizal inoculation, sheep penning, and sheep penning with mycorrhizal inoculation), at two mountain sites in Sierra Nevada Natural Park (Granada, southern Spain). The first site, Soportujar, had higher soil fertility and rainfall than the second, Lanjaron. Forage yields in Soportujar ranged from 265 to 8970 kg DM ha−1, Vicia amphicarpa, Vicia monantha, Vicia disperma and Lathyrus clymenum being the most productive species. Mycorrhizal inoculation resulted in higher forage yields for Lens nigricans, V. disperma and Vicia lutea. Seed yields were low, ranging from 5.9 to 1234 kg ha−1. Forage yields in Lanjaron were lower, ranging from 46 to 1415 kg DM ha−1; and the most productive species were V. monantha, V. disperma, Lathyrus cicera and Medicago rigidula. Sheep penning alone and together with mycorrhizal treatment resulted in greater forage yields for most of the species studied, although differences were only significant for V. disperma, V. monantha and Lathyrus sphaericus. Seed yields ranged from 0.4 to 60 kg ha−1. In conclusion, we recommend V. monantha, V. disperma and L. cicera followed by V. amphicarpa and L. clymenum (in wetter more fertile sites) and M. rigidula (in drier sites), as they seem to be the best adapted to the pedoclimatic conditions of Sierra Nevada Natural Park. Increasing nutrients in the soil (by sheep penning) and promoting nutrient assimilation (by mycorrhizal inoculation) may be effective strategies for increasing pasture biomass in silvopastoral sites.