Fodder value and physiological aspects of rainfed smooth vetch affected by biofertilizers and supplementary irrigation in an agri-silviculture system

In an agri-silviculture of the plum (Prunus domestica L. Cv. Opal), the forage quality of smooth vetch (Vicia dasycarpa L.) was evaluated. For this purpose, a two-year (2016 and 2017) factorial experiment was conducted based on randomized complete block design with three replications at Urmia University, Iran. The treatments included the combined and individual application of biofertilizers {Azotobacter chroococcum (Az), Thiobacillus spp. (Th)., Rhizophagus intraradices (AMF) and control} under rainfed and once supplementary irrigation. The results showed that irrigated plants contained higher P than rainfed plants. Dual inoculation with “AMF + Az” had higher Ash, K, CP and WSC than plants with fungal or bacterial inoculation alone. In comparison with control, biofertilizers improved the forage and protein yield by 32 and 45.50% under rainfed conditions and by 47 and 60.04% under supplementary irrigation, respectively. The amount of CAT, GR, APX, and SOD were reduced in rainfed plants, but the co-inoculation of mycorrhizal plants with Az and/or Th enhanced enzymatic antioxidants. In conclusion, the combined use of AMF and Az improved smooth vetch forage quantity and quality in irrigated plants as much as rainfed did, and hence it can be desirable for sustainable agriculture.