Herbage Responses and Biological N₂ Fixation of Bahiagrass and Rhizoma Peanut Monocultures Compared with their Binary Mixtures

Abstract

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.

Rhizoma peanut herbage and root–rhizome responses to extended regrowth periods

“…Herbage accumulation of Beta was greater than that reported by Santos et al. (2018) in a 2‐yr experiment in which Beta (5.4 Mg ha −1 yr −1 ) and the germplasm Ecoturf RP were harvested by clipping four times per year. In that study, annual HA of Ecoturf was 5.0 Mg ha −1 compared with 3.9 Mg ha −1 (1× treatment) and 10.5 Mg ha −1 (2× treatment) in the current experiment.…”

Establishment techniques affect productivity, nutritive value and atmospheric N2 fixation of two sunn hemp cultivars

“…In general, bahiagrass ( Paspalum notatum Flügge), and bermudagrasses ( Cynodon spp. ), two of the most common pasture species in the southeastern United States, tend to have CP concentrations ranging between 80 and 120 g/kg, and digestibility ranging between 400 and 520 g/kg (Agyin‐Birikorang, Newman, & Kasozi, 2012; Jaramillo et al, 2018; Santos et al, 2018).…”

Soil Chemical Changes and Resemblances in a Chronosequence Rainforest-Sugarcane-Pastureland in the Atlantic Forest Biome

“…According to Stevenson et al (2010), others processes that fractionate the δ 15 N in the soil are nitrification are denitrification and ammonia volatilization, in their study, there were greater δ 15 N in cultivated soils compared to native forests. The δ 15 N signature in plants can also increase when N fertilizer is applied (Santos et al, 2018). Santos et al (2018) reported an enrichment of the δ 15 N of Paspalum notatum roots after two years of N fertilization, the response was credited to a possible increase in the availability of SOM-N (rich in δ 15 N) after N fertilization, and due to the decrease in the C:N ratio.…”

“…The δ 15 N signature in plants can also increase when N fertilizer is applied (Santos et al, 2018). Santos et al (2018) reported an enrichment of the δ 15 N of Paspalum notatum roots after two years of N fertilization, the response was credited to a possible increase in the availability of SOM-N (rich in δ 15 N) after N fertilization, and due to the decrease in the C:N ratio. Similar to our results, Franco et al (2015) evaluating areas of a chronosequence (forest-pasture-sugarcane) also reported higher δ 15 N in sugarcane areas.…”