Infrequent and intense defoliation benefits dry‐matter accumulation and persistence of clipped Arrhenatherum elatius

Abstract

The objective was to determine how the frequency and intensity of defoliation of tall oat grass [Arrhenatherum elatius (L.) Presl.], affected (i) annual dry-matter (DM) accumulation, (ii) seasonal distribution of the accumulated forage, and (iii) morphological traits related to persistence and vigour. Data were collected twice a year throughout three growing years, beginning the second year after establishment. Two frequencies (A: each time modal height of plants reached 20 cm; B: each time modal height of plants reached 40 cm) and two defoliation intensities (I: 5 cm; II: 10 cm stubble) were arranged in a completely randomized block design with a fully factorial combination and four replicates. Measurements were made of annual DM accumulation, seasonal distribution of accumulated DM and morphological traits related to persistence and vigour, i.e. number of tillers m )2 , number of tussocks m )2 , crown diameter, and crown area of tussocks. The infrequent defoliation (B) increased annual DM accumulation besides maintaining levels of persistence and vigour. The most productive treatment (BI) had a significantly higher annual DM accumulation than treatments AI and AII. Frequent and severe defoliations (treatment AI) led to plant depletion, which reduced crown diameter, number of tillers m )2 and crown area at the end of the third year compared with infrequent but severe defoliation (treatment BI). Annual DM accumulation was intermediate for less intense defoliations (AII), which produced forage during winter, but resulted in less vigorous plants by the end of the experiment.Crown area was a good indicator of tiller number, particularly under frequent defoliation.

Harvest management based on leaf stage of a tetraploid vs. a diploid cultivar of annual ryegrass

“…Among ryegrasses, instituting a forage management approach of low post‐defoliation residual stubble height resulted in a consistent greater tiller population density compared to ryegrasses harvested at higher residual stubble surface height (e.g., Grant, Barthram, Torvell, King, & Smith, ; Matthew, Lemaire, Sackville Hamilton, & Hernandez‐Garay, ; Yu, Nan, & Matthew, ). Other studies using different forage species have reported increased tiller density at intense defoliation (lower RSH) compared to lenient defoliation (higher RSH post‐defoliation) (e.g., Malinowski, Hopkins, Pinchak, Sij, & Ansley, ; Sbrissia et al., ) while others have reported contrasting results of greater tiller density at lenient compared to intense defoliation (D'Angelo, Postulka, & Ferrari, ; Hamilton et al., ; Kalmbacher, Martin, & Pitman, ; Volesky & Anderson, ). Yet, others have reported no effect of residual stubble height post‐defoliation on tiller density (e.g., Hamilton et al., ; Lee et al., ; Montagner et al., ).…”

Effects of nitrogen fertilization and cutting intensity on the agronomic performance of warm‐season grasses

“…Cutting intensity affects the productivity and the nutritive value of forage plants, partly by changing their morphological development (Liu et al ., ; Fontes et al ., ). Consequently, each species responds differently to the intensity of defoliation because it is related to the morphological and physiological characteristics of a species (D'Angelo et al ., ). Nitrogen supply has a positive effect on the aboveground productivity of forage plants because it is a major factor responsible for increasing the tiller density, number of leaves and leaf area of forage plants (Premazzi et al ., ; Lavres et al ., ; Pitman, ).…”

“…C70) associated with limiting N nutrition simulates the typical management of extensively used tropical grasslands in Brazil. A high cutting intensity encourages herbage accumulation (D'Angelo et al ., ). However, less severe cutting has been proposed (e.g.…”

Dinámica de crecimiento y calidad nutritiva de una pradera de Lolium perenne L. sometida a diferentes frecuencias de defoliación: periodo primavera-verano

“…En el presente trabajo se observó que, en general, el crecimiento acumulado (g MS m -2 ) de las minipraderas fue mayor en aquellas que fueron defoliadas de manera menos frecuente. Estos resultados concuerdan con lo señalado por diversos autores para especies como Lolium perenne, Bromus willdenowii, Dactylis glomerata, Lolium multiflorum, Trifolium subterraneum, Trifolium repens, Festuca arundinacea y Arrhenatherum eliatus (Donaghy y Fulkerson, 1997Fulkerson y Slack, 2003;Velasco et al, 2005Velasco et al, , 2007Poff et al 2011;Castro, 2010;Turner et al (2006a); Callow et al, 2005;Donaghy et al, 2008;D' Angelo et al, 2005).…”

“…Diversos estudios han demostrado que a menor frecuencia de defoliación, mayor es la producción de materia seca obtenida en diferentes especies forrajeras, tales como Lolium perenne, Bromus willdenowii kunth, Dactylis glomerata L., Lolium multiflorum Lam., Trifolium subterraneum L., Festuca arundinacea Schreber y Arrhenatherum elatius L. (Fulkerson y Slack, 2003;Turner et al, 2006a;Callow et al, 2005;Donaghy et al, 2008;D' Angelo et al, 2005).…”