Rhizome Characteristics and Canopy Light Interception of Grazed Rhizoma Peanut Pastures

Abstract

‘Florigraze’ rhizoma peanut (Arachis glabrata Benth.) is a promising pasture legume for warm climates. In 1988 and 1989, the effect of grazing management on rhizoma peanut canopy light interception (LI) and the role of rhizome reserves in regrowth were studied on a Sparr fine sand (loamy, siliceous, hyperthermic Grossarenic Paleudults). Treatments were replicated twice and included all combinations of three levels of residual dry matter (RDM; 500, 1500, and 2500 kg ha−1) and four grazing cycle lengths (GC; 7, 21, 42, and 63 d between grazings, including a 0.5 to 2‐d grazing period). Data were analyzed by fitting multiple regression equations starting with a second order polynomial model. Canopy LI before grazing ranged from 24 to more than 90% and was lowest for low RDM and short GC treatments, while canopy LI after grazing ranged from 9 to 79% and increased at a decreasing rate as RDM increased. When grazed to 500, 1500, and 2500 kg ha−1, RP required an average of 49, 24, and 12 d to reach 85% LI. At season‐end 1989, rhizome mass (range of 450‐4100 kg ha−1) and total nonstructural carbohydrate (TNC; range of 58‐210 g kg−) concentration were lowest at low RDM and short GC, increased with increasing GC when RDM was low, and changed only slightly with changes in GC at RDM above 1700 kg ha−1. Low postgraze light interception and depletion of rhizome mass and total nonstructural carbohydrate with close grazing suggest that reserves were mobilized for rhizoma peanut regrowth. In contrast, postgraze light interception and rhizome mass and reserve status remained high when residual dry matter was 1700 kg ha−1 or greater suggesting that residual leaf area was primarily responsible for regrowth under more lenient grazing.

Sward Structure, Light Interception, and Rhizome‐Root Responses of Rhizoma Peanut Cultivars and Germplasm to Grazing Management

“…Rhizome‐root TNC concentration was not affected by grazing treatment or entry but it did increase ( P < 0.001) from an average of 115 g TNC kg ‐1 DM in June and October 2012 to 142 g TNC kg ‐1 DM in October 2013, the end of the second year of grazing. These concentrations fall within the range for Florigraze rhizomes (100–200 g kg ‐1 ) reported by Saldivar et al (1992), when plants were clipped at intervals from 2 to 8 wk, and by Ortega‐S. et al (1992a ; 58–210 g kg ‐1 ) across a range of grazing frequencies (7–63 d) and intensities (residual herbage mass of 500– 2500 kg ha ‐1 ).…”

“…Thus, regeneration of leaf area was likely slower for the uprightgrowing UF Tito than the other entries when grazed more severely, and the decumbent growth habit of Ecoturf provided an advantage in terms of pre-grazing LI only when pastures were grazed very heavily. Like the response for UF Tito in the current study, Ortega-S. et al (1992a) observed that a longer regrowth interval was needed to achieve 85% pre-grazing LI for Florigraze RP when residual herbage mass after grazing was 500 vs. 2500 kg ha -1 .…”

“…There were no differences in rhizome‐root mass at the end of the first year of grazing (mean of 3760 kg ha ‐1 ); however, by the end of Year 2, RP grazed every 6 wk had greater rhizome‐root mass than when defoliated every 3 wk (3990 vs. 2730 kg ha ‐1 ). Ortega‐S. et al (1992a) observed no differences in Florigraze RP rhizome‐root mass among a wide range of grazing treatments following one year of grazing, but by the end of Year 2, rhizome‐root mass ranged from 400 to 4100 kg ha ‐1 among treatments, with lowest mass associated with frequent, close grazing.…”

Organic farming: effects of forage to concentrate ratio and ageing time on meat quality of Podolian young bulls

“…Water was always available for all the animals. Sward composition was measured prior to the beginning of the experiment and then at monthly intervals throughout the trial using a double sampling technique (Ortega et al, 1992). Forage mass was adjusted for growth during each period using estimates of yard growth derived from cutting 10 randomly selected 1 m 2 sites in adjacent ungrazed yard.…”

Phenotypic Plasticity and Other Forage Responses to Grazing Management of Ecoturf Rhizoma Peanut

“…under a range of management strategies makes it a candidate legume for use in grazed pasture (Ortega-S. et al, 1992a(Ortega-S. et al, , 1992b. Documented persistence of rhizoma peanut (RP, Arachis glabrata Benth.)…”