Establishment and production of lucerne (Medicago sativa L.) in Sweden is affected by inoculation product choice

Lucerne ( Medicago sativa L.) is an important perennial forage legume in Sweden, but its potential cultivation area is constrained by uncertainty of successful establishment. This study aimed to identify management practices that could lead to improved establishment of lucerne. Lucerne cultivar SW Nexus was grown at four different locations in southern Sweden over two establishment/production cycles. At all locations except Svalöv, lucerne had not previously been cultivated in the plot location for at least seven years. Inoculation treatments of one standard rhizobia (Nitragin Gold, NG), two NG-related, three NGs combined with single micronutrient, and six alternative inoculants were assessed in comparison with a no inoculation control for their effects on lucerne establishment and production. The results showed that alternative inoculants were sometimes better than the standard inoculants. The largest contrast between different inoculation treatments was at Rådde in the first crop cycle, where the best treatment yielded 12000 kg DM ha -1 across three harvests, nearly twice that of the control, and all alternative inoculant treatments had higher total nitrogen concentration (TN), lower carbon to nitrogen ratio (C:N), and greater normalised difference vegetation index (NDVI) than the control. There was no evidence that the soil-applied micronutrients improved yield at any location. At Svalöv, where lucerne had previously been grown, there was no effect of any of the treatments. In conclusion, inoculation is essential at locations where there is no history of lucerne cultivation, and choice of inoculation product can affect establishment and production. • Choice of inoculants affects lucerne establishment and production in Sweden. • Alternative inoculants were sometimes better than the standard inoculant. • Soil-applied micronutrients did not show benefit in any instance. • No effects of inoculation in fields with recent history of lucerne cultivation. • Seed inoculation is an insurance for a well-established and productive lucerne crop.