Nodulation of Inoculated and Non-Inoculated Peanuts Planted with Various Rates of Starter N Fertilizer.

Nodulation is important in forming a healthy peanut (Arachis hypogaea L.) plant and maximizing plant nutrition and yields.  Peanuts were planted in a field after 25 years continuous corn (Zea mays L.) to compare effects of inoculant treatments (none, Optimize Lift, Vault Liquid, and Vault SP) and their interaction with rates of starter N fertilizer applied at planting (0, 17, 34, and 67 kg N ha^-1).  A two factor factorial design was used for each combination of the four inoculant and four N rate treatments with four replications at the ABAC farm in Tifton, GA.  Nodules and roots were removed from field on July 29 and weighed, dried, and weighed again.  There was a significant interaction between inoculants and N rates for fresh nodule weight only.  There were no differences among the N rates.  However, there were significant differences among inoculants for dry nodule weights and Nodule:Root.  For all factors, Optimize Lift (dry nodules = 0.815 g) and Vault Liquid (dry nodules = 0.753) provided superior nodulation to Vault SP (dry nodules = 0.201 g) and non-inoculated peanuts (dry nodules = 0.035 g).  In the fresh nodule interaction, the apparent trend was that there were no differences in nodulation regardless of N rate for Vault SP or non-inoculated peanuts, but nodulation was greatly reduced at 67 kg N ha^-1 for peanuts inoculated with Optimize Lift or Vault Liquid.