The Forage Productivity of Yellow Sweetclover in Agroforestry System (Plum Trees)

An effective way to improve drought tolerance of plants is arbuscular mycorrhizal fungi (AMF) symbiosis. Mycorrhizal plants can develop water balance in irrigated and drought conditions (Auge, 2001) by enhancing shoot and root growth, biomass and the antioxidant system (Li et al., 2015). Yellow sweetclover [Melilotus officinalis (L.)] is renowned as a medicinal plant (Karakas et al., 2012). This plant is used as forage (Meyer, 2005). A split-plot experiment was carried out in plum (Prunus domestica) orchard for 2 years (2016-2017) based on complete block design with three replications, situated at North-West of IRAN (37º62´N and 44º58´E, altitude 1333 m). The forage productivity of yellow sweetclover with inoculation of two species of AMF (Funneliformis mosseae or Rhizophagus irregularis) was evaluated in sunny and shady areas in rainfed system and supplementary irrigation for two years. Our results showed that in supplementary irrigation, AMF-inoculation enhanced plant fresh weight in sunny area much more than untreated control plants in sunny and shady areas and inoculated plants in shady area for both two years. In rainfed system, AMF inoculated plants in sunny area had higher fresh weight relative to non-inoculated plants in sunny and shady areas. In both two years, Inoculation with R. irregularis increased plant fresh weight up to 4.88% compared to mycorrhization with F. mosseae. In summary, AMF inoculation improved plant fresh weight despite of irrigation system.