Performance of Limpograss Breeding Lines under Various Grazing Management Strategies

Abstract

Limpograss [Hemarthria altissima (Poir.) Stapf et C.E. Hubb.] is a C4, perennial, stoloniferous grass that is well adapted to poorly drained soils and grows throughout frost‐free periods during winter in southern Florida. Its use has increased rapidly in recent decades, but nearly all area in cultivation is planted with one cultivar, ‘Floralta’. A breeding program was initiated to develop improved alternatives to Floralta, resulting in a group of breeding lines requiring evaluation under grazing. The objective of this research was to evaluate the performance of five limpograss breeding lines (1, 4F, 10, 32, and 34) under combinations of grazing frequency and intensity. During the 2012 and 2013 growing seasons, those lines, plus Floralta, were tested at two pre‐grazing canopy light interception levels (80 and 95%), that triggered the initiation of each grazing event, and two post‐grazing stubble heights (20 and 30 cm). Lines 4F and 10 had greater herbage accumulation, apparent herbage harvested, and persistence than Floralta. Initiation of grazing at 80% canopy light interception resulted in more frequent grazing events, a longer grazing season, shorter pre‐grazing canopy height, greater leaf percentage, less herbage bulk density, and greater herbage crude protein concentration compared with 95% canopy light interception. These data support cultivar release of breeding lines 4F and 10 and suggest that persistence and efficient utilization of limpograss under rotational stocking can likely be achieved by initiating grazing at a pre‐grazing canopy height of ∼60 cm, well before 95% canopy light interception, and by ending grazing at a post‐grazing canopy height of ∼30 cm.

Harvest Management Effects on Canopy Height and Light Interception of ‘Performer’ Switchgrass and its Relationship with Weed Infestation

“…† Figure CH to replenish due to intense defoliation regimes, the result is subsequent weakened and loss of stands. Hubb], Wallau et al (2016) concluded that light interception values to trigger initiation of defoliation and conducive to optimize growth and utilization of forage may be influenced by plant growth habit and sward structure. Frequently clipped treatments to lower DH (i.e., harvest every 3 wk to 10-and 20-cm stubble height) imposed during 2 yr to a well-established switchgrass stand (>8 yr old) were discontinued due to loss of switchgrass stand and observed presence of weeds (Bekewe et al, 2018).…”

Registration of ‘Kenhy’ and ‘Gibtuck’ Limpograss Hybrids

“…As far as we are aware, these two limpograss hybrids represent the first release of genetically recombined germplasm in this species (all previous releases were plant introductions collected from native conditions in Africa). Table 2 in Wallau et al (2016). Reprinted with permission.…”

“…Herbage IVDOM was not different among entries 1, 4F, 10, and Floralta (data not shown). Additional experimental details and results can be found in Wallau et al (2016).…”

“…Treatments were the factorial combinations of two grazing frequencies (initiation of grazing at 80 and 95% pregrazing canopy light interception) and two postgrazing stubble heights (20 and 30 cm). Pastures were fertilized with 120 kg N ha -1 yr -1 in three applications of 40 kg N ha -1 (see Wallau et al [2016] for additional experimental details).…”

“…Floralta has received wide acceptance for use in southern Florida and is estimated to be planted on more than 200,000 ha in the state (Wallau et al, 2016). Reasons for the widespread adoption and use of Floralta limpograss on extensive beef cattle operations include superior winter forage production and greater digestibility, especially at mature growth stages, than bahiagrass ( Paspalum notatum Flügge) and bermudagrass [ Cynodon dactylon (L.) Pers.…”