Frequencies and intensities of defoliation in Aruana guineagrass swards: morphogenetic and structural characteristics

Abstract

-The objective of this study was to evaluate the morphogenetic and structural characteristics of Aruana influenced by the frequency and intensity of grazing adopted, as well as by the seasons, implying that the capacity and speed for the recovery of Aruana grass pastures after grazing depend mainly on the management and edaphoclimatic conditions. The best grazing management for Aruana guineagrass is 95% canopy light interception, i.e., 30 cm pre-grazing height pastures interrupted when reaching 15 cm residue.

Ecophysiology of C4 Forage Grasses—Understanding Plant Growth for Optimising Their Use and Management

“…In addition, long grazing intervals characterized by the pre-grazing target of LImax result in a greater proportion of the produced herbage being lost to the soil as a consequence of physical damage and/or rejection, decreasing the efficiency of the grazing process [85,90,91]. The investment in stem elongation results in taller swards with an increased proportion of stems in the upper layers of their vertical profile [92], increasing the difficulty of grazing and in maintaining the post-grazing management targets [93,94]. As a result, the benefit of greater total herbage accumulation is offset by the greater grazing losses when long regrowth intervals are used, indicating that, although herbage accumulation per grazing cycle is smaller when managing with shorter grazing intervals (LI95%), the more frequent defoliation results in larger number of grazing cycles and total herbage accumulation (with higher leaf proportion) than when managing with longer grazing intervals (LImax) [84,91,94,95].…”

“…Marandu) [101], Panicum maximum cv. Aruana [93], and Pennisetum purpureum cv. Napier [94,95], showing consistency within a wide range of morphological types and a strong light effect determining plant growth.…”

“…This pattern of variation in the short-term rate of intake in relation to the decreasing sward height during grazing was formally described by Fonseca et al [127,132] and corroborated by Mezzalira et al [128], indicating the potential for manipulating pre-and post-grazing conditions as a means of optimising herbage production and intake in rotationally managed pastures. In general, more frequent defoliations (at 95% canopy light interception) than traditionally used, associated with moderate grazing severity (post-grazing heights around 50% of the pre-grazing height), result in greater leaf dry matter production [84,93,96,124], higher nutritive value [89,90] and intake rate of animals [127][128][129]132], augmenting animal performance and productivity [133], indicating that rational intensification of grassland use could be an effective way of ensuring sustainability of tropical pastoral systems of animal production. These results are in line with the findings of Knoke et al [134] and provide feasible options for recovering degraded areas, reducing pressure on forest lands and releasing additional area for cropping and food production.…”

<b>Sward structure, light interception and herbage accumulation in forage peanut cv. Belmonte subjected to strategies of intermittent grazing management

“…Under rotational grazing, recent studies focused on tropical grasses have shown that light interception (LI) is the best criteria to determine ideal grazing events, during regrowth (Barbosa et al, 2007;Carnevalli et al, 2006;Zanini, Santos, & Sbrissia, 2012). Optimal net forage accumulation (i.e.…”

Estrutura do dossel, interceptação de luz e acúmulo de forragem em amendoim-forrageiro (<i>Arachis pintoi </i>Krapovickas &amp; Gregory cv. Belmonte) submetido a estratégias de pastejo rotativo

“…Particularmente, sob pastejo rotativo, estudos recentes realizados com gramíneas tropicais (CARNEVALLI et al, 2006;BARBOSA et al, 2007;ZANINI;SBRISSIA, 2012) apontaram a interceptação luminosa durante a rebrotação como critério adequado para definição do ponto ideal para realização do pastejo. Adicionalmente, foi demonstrada a importância de se definir a altura de saída dos animais dos pastos, uma vez que esta se relaciona diretamente com o consumo de forragem e a ingestão de nutrientes pelos animais (CARVALHO et al, 2009), perdas e eficiência de pastejo (CARNEVALLI et al, 2006;SILVEIRA et al, 2013) e velocidade de rebrotação (DA SILVA et al, 2009).…”