Tifton-85 Bermudagrass Mixed with Annual or Perennial Peanuts for Hay Production in North Florida.

Rhizoma peanut (Arachis glabrata Benth.) is one of few warm-season perennial legumes available for producers in the southeastern USA. High costs associated with planting and its slow establishment have reduced its adoption. Seeded peanut (A. pintoi Krapov. & W.C. Greg., and A. hypogea L.), with proper management, can be viable alternatives. In this project, four different Arachis entries were evaluated when established in ‘Tifton 85’ bermudagrass (Cynodon spp.). Treatments consisted of: 1) A. glabrata cv. Florigraze; 2) A. glabrata germplasm Ecoturf; 3) A. pintoi cv. Amarillo; 4) A. hypogea cv. TUFRunner 727; and 5) Tifton 85 monoculture without N fertilizer. The experimental design was a randomized block with four replications. Grass and peanut were established on the same date in April 2014. Plots were harvested every 5 wk during 2015 and 2016. Mixtures (306 kg DM ha^-1 harvest^-1) yielded more (P = 0.008) than unfertilized grass plots (200 kg DM ha^-1 harvest^-1) in 2015. Weed control was problematic and reduced yields in 2015, but in 2016 Ecoturf followed by Florigraze mixtures produced greater biomass than other treatments because of greater legume yields. In three out of four evaluations, N concentration was greater for A. hypogea (average of 30 g kg^-1) compared with A. glabrata cultivars (average of 25 g kg^-1). Grass yield was similar among treatments (P > 0.05), but grass N concentration was greater when mixed with A. glabrata compared with A. pintoi (16.8 vs. 14.8 g kg^-1, respectively). Because of the small contribution of legume to the swards, biological N₂-fixation by shoots was negligible in the first year, but it increased in the second year, particularly for A. glabrata mixtures. In hay systems with low N inputs, mixtures of Arachis glabrata and Tifton 85 bermudagrass performed better than seeded peanut or unfertilized Tifton85 bermudagrass.