Leaf number as a criterion for determining defoliation time for Lolium perenne: 2. Effect of defoliation frequency and height

Abstract

The object of this study was to determine the importance of frequency and height of defoliation on regrowth potential of Lolium perenne. Defoliation interval was based on stage of the regrowth cycle, as indicated by leaves per tiller.Simulated swards of Lolium perenne cv Yatsyn were grown as individual plants in a glasshouse kept at a day/night temperature of 25°C/15''C.Treatments imposed were defoliation at 2, 5 or 12 cm residual height, and low and high water soluble carbohydrate (WSC) level obtained by varying defoliation interval, i.e. defoliating at the I-leaf or 3-leaf stage of the regrowth cycle. Regrowth after freqtient short defoliations was only 65% of the less frequently defoliated plants taken over the full regrowth cycle. This was associated with a lower stubble WSC content (2-15 vs 17-5% in stubble) and a twenty-seven-fold difference in the amount of WSC in the stubble per plant. This difference in total WSC was a combined effect of more and heavier tillers and higher WSC content in stubble of plants defoliated less frequently at the end of the regrowth cycle. The regrowth of plants with WSC levels depleted by frequent defoliation when defoliated at 2 cm was significantly below that of those defoliated at 5 and 12 cm.The results indicate the desirability of defoliating plants at the 3-leaf stage of the regrowth cycle. This not only allows the full regrowth potential to be expressed in that growth cycle, but also in the next cycle, by allowing the replenishment of WSC reserves and optimizing tiller status. The potential to regrow appears then to be based more on the total CofTespondence: W. J. Fulker^on. NSW Agriculture, Wollnngbar Agriculwral Institute. Woliongbar, NSW 2477, Australia. amount of WSC than the proportion of WSC in stubble.

Forage production of elephant grass under intermittent stocking

“…In both light interception levels, a lower rest period was found with the higher residue (50 cm). This finding is supported by the literature, with shorter intervals at lower grazing intensities (Korte et al, 1982;Fulkerson & Slack, 1995;Barbosa et al, 2007). This response is associated with the higher height of the genotype CNPGL 00-1-3, which was reflected in a greater canopy height.…”

Effect of pre-grazing herbage mass on dairy cow performance, grass dry matter production and output from perennial ryegrass (Lolium perenne L.) pastures

“…In the current study, the L pastures recorded the shortest regrowth interval during the June to July period (15 days); it was during this period that the treatment effect on pasture growth was most pronounced. Fulkerson and Slack (1995) 0.12 0.10 0.14 ns 0.05 DM = dry matter; HM = herbage mass; DHA = daily herbage allowance; s.e.d. = standard error of the difference; ns = not significant.…”

Características morfogênicas e estruturais na rebrotação da Brachiaria brizantha cv. marandu submetida a três doses de nitrogênio

“…No presente trabalho, o filocrono foi, em média, de 12,20; 8,47; e 6,99 dias folha -1 , respectivamente, para as plantas que receberam 0, 20 e 40 mg/dm -3 semana -1 de N. Como o número de folhas vivas perfilho -1 é definido pela espécie (Fulkerson & Slack, 1995), pode-se inferir que as plantas recebendo N irão atingir seu número máximo de folhas vivas perfilho -1 mais precocemente, em relação às não-adubadas, promovendo, com isso, a possibilidade de colheitas mais freqüentes, a fim de evitar perdas por senescência foliar.…”