Grasslands in warm‐climate regions are often based on grass monocultures, increasing their dependence on N fertilizers. Integrating perennial legumes into grass pastures is a logical option. The objective of this 2‐yr study was to assess seven rhizoma peanut (Arachis glabrata Benth) cultivars: Arbrook, Arblick, Ecoturf, Florigraze, Latitude 34, UF Peace, and UF Tito. Above‐ and belowground responses included biomass, in vitro organic matter disappearance (IVOMD), N concentration, N content, δ15N, proportion of N derived from atmosphere (%Ndfa), and biological N2 fixation (BNF). Arbrook was more productive than Florigraze in both years (P ≤ 0.05) but produced similar biomass to other varieties in 2014. In 2015, Arbrook also was more productive than Arblick and Latitude 34. Herbage N concentration ranged from 19.2 to 36.3 g kg−1. Arbrook tended to be less digestible than other rhizoma peanut cultivars. The BNF represented >80% of herbage N and averaged 200 kg N ha−1 yr−1, with values ranging from 123 to 280 kg N ha−1 yr−1. Root and rhizome biomass varied among cultivars, with Ecoturf (26.9 Mg organic matter [OM] ha−1) and Latitude 34 (27.8 Mg OM ha−1) presenting greater root and rhizome mass than Florigraze (10.5 Mg OM ha−1) but similar to other varieties. Roots and rhizomes represented a significant portion of the total biomass and N pool, and further studies are needed to assess turnover of these tissues as well as their N contribution in grazing systems using grass–rhizoma peanut mixtures.

Fertilization of perennial grass pastures is a major expense in beef cattle operations, and grass pastures may degrade in the absence of N fertilization. Grass–legume mixtures can reduce the demand for N fertilizer use while increasing productivity of the system. Arachis spp. have shown potential for use in association with grasses in the southeastern United States. During 2014, 2015, and 2016, we evaluated one annual peanut species (Arachis hypogaea L. TUFRunner ‘727’) and two perennial peanut species, pintoi peanut (A. pintoi Krap. & W.C. Greg ‘Amarillo’) and rhizoma peanut (A. glabrata Benth. ‘Florigraze’ and germplasm Ecoturf), when planted into previously established ‘Pensacola’ bahiagrass (Paspalum notatum Flügge) sod. Responses measured included herbage accumulation (HA), botanical composition, nutritive value, biological N2 fixation, and belowground root‐rhizome responses. TUFRunner 727 showed reseeding ability, illustrating potential for use as a short‐term forage, but by 2016, its contribution was negligible. In 2016, Ecoturf–bahiagrass had greater HA than unfertilized bahiagrass (4160 and 2710 kg ha−1, respectively), and the Ecoturf contribution to HA was ∼30% in 2016. Average N concentrations for Ecoturf and Florigraze were 25 and 22 g kg−1, respectively, and in vitro digestible organic matter concentration was 700 g kg−1 for both. Pintoi peanut contributed little to mixture HA in the first 2 yr, but it persisted and increased in proportion with time. Over the course of 3 yr, Ecoturf rhizoma peanut performed better than all other entries, exhibiting increasing participation in mixtures each year and the greatest total HA in 2016.

Bahiagrass (Paspalum notatum Flüggé) and rhizoma peanut (RP, Arachis glabrata Benth.) are widely used in Florida, and growing them in association may decrease the need for N fertilization. This study evaluated herbage responses of mixed RP-bahiagrass swards in comparison with their monocultures. The eight treatments were two bahiagrass entries ('Argentine' and DF9, receiving 90 kg N ha −1 harvest −1 ) and two RP entries (Ecoturf and Q6B) in monoculture and the combinations of each bahiagrass with each RP (Argentine-Ecoturf, Argentine-Q6B, DF9-Ecoturf, and DF9-Q6B). There was no difference in total herbage accumulation (HA) in 2015. In 2016, total HA was greatest for Argentine + N (9630 kg dry matter [DM] ha −1 ), followed by the mixture Q6B-DF9 (5910 kg DM ha −1 ). Mixtures produced as much biomass as RP monocultures and DF9 + N. In mixtures, Argentine was the most competitive bahiagrass, whereas Q6B was the most competitive RP. Crude protein concentration of DF9 in the mixture with Q6B was similar to that of N-fertilized DF9. The total aboveground N was usually greatest in RP monocultures (50-53 kg N ha −1 harvest −1 ). Percentage of N derived from the atmosphere increased by 22% in Q6B from 2015 to 2016. Biological N 2 fixation ranged from 11 (Ecoturf-Argentine) to 44 kg N ha −1 harvest −1 (Ecoturf and Q6B). Entry growth habit affected the proportion of each component in the sward, and this information is crucial when combining warm season grasses and legumes. Rhizoma peanut will add N to bahiagrass systems and improve forage nutritive value but have less HA than heavily fertilized grass.

Plant litter deposition and decomposition play important roles in grassland nutrient cycling. The objective was to evaluate plant litter responses and estimate the N returns via plant litter in contrasting grazing systems, since legume inclusion is hypothesized to result in similar quantities of N return compared with N‐fertilized grass systems. Systems were (a) N‐fertilized bahiagrass (Paspalum notatum Flüggé) during summer with a mixture of N‐fertilized cereal rye (Secale cereale L.) and oat (Avena sativa L.) during winter (Grass+N); (b) bahiagrass (no N fertilizer) during summer and a rye–oat–clovers (Trifolium spp.) mixture + N in winter (Grass+Clover); and (c) bahiagrass (no N fertilizer in summer) with strip‐planted rhizoma peanut (Arachis glabrata Benth.) during summer with a rye–oat–clovers mixture + N during winter (Grass+CL+RP). Litter mass was greatest for Grass+N during October (4,430 kg organic matter [OM] ha−1) and least for Grass+CL+RP in June (490 kg OM ha−1). Litter N concentrations were greatest in Grass+N (16 g kg−1), with similar N concentration for Grass+Clover and Grass+CL+RP litter (14 g kg−1). Contribution of C3 species to litter mass increased from May to July but decreased thereafter. Overall, there was a net return of 47 kg N ha−1 yr−1 via litter across the three systems, and litter decomposition was similar in the three systems. Inclusion of forage legumes during cool and warm seasons in grazing systems has the potential to return similar amounts of N through plant litter deposition as grasses receiving moderate levels of N fertilizer.