<b>Defoliation patterns in signal grass tillers with varying heights in the same pasture</b> - doi: 10.4025/actascianimsci.v35i3.14376

Abstract

ABSTRACT. The experiment was carried out to evaluate the patterns of defoliation in plants of various heights in the same pasture of Brachiaria decumbens cv. Basilisk under continuous stocking with cattle. Four plant heights were evaluated (10, 20, 30 and 40 cm) in the same managed sward, with mean height equal to 25 cm. A randomized blocks design was used, with two replications. Defoliation frequency increased linearly along with plant height in the same pasture. Defoliation intensity, number of defoliations in leaf blade and percentage of leaf blade grazed per tiller also increased linearly along with plant height. The defoliation interval decreased linearly according to plant height. The quadratic model was adequately fitted into grazing efficiency data, reaching the highest value (98%) at the sward site with 35 cm plants. The percentage variation in signal grass height showed a negative linear response with initial plant height. The structure of the pasture, characterized by the diversity in plant heights, is simultaneously the cause and consequence of the variability in defoliation patterns in individual tillers, which occur on the horizontal plane of the pasture.Keywords: Brachiaria decumbens, forage losses, grazing, horizontal pasture sward.Padrões de desfolhação em perfilhos de capim-braquiária com alturas variáveis no mesmo pasto RESUMO. O experimento foi conduzido para avaliar os padrões de desfolhação em plantas com alturas variáveis no mesmo pasto de Brachiaria decumbens cv. Basilisk sob lotação contínua com bovinos. Foram avaliadas quatro alturas de plantas (10, 20, 30 e 40 cm) no mesmo pasto manejado com altura média de 25 cm. Adotou-se o delineamento em blocos ao acaso com duas repetições. A frequência de desfolhação aumentou linearmente com a altura da planta no mesmo pasto. A intensidade de desfolhação, o número de desfolhações na lâmina foliar e o percentual de lâmina foliar pastejada por perfilho também incrementaram de forma linear com a altura da planta. O intervalo de desfolhação diminuiu linearmente com a altura da planta. O modelo quadrático foi ajustado adequadamente aos dados de eficiência de pastejo, obtendo-se o valor máximo (98%) no local do pasto com plantas de 35 cm. A variação percentual na altura do capim-braquiária apresentou resposta linear negativa com a altura inicial da planta. A estrutura do pasto, caracterizada pela sua diversidade de alturas de plantas, é, concomitantemente, causa e consequência da variabilidade dos padrões de desfolhação em perfilhos individuais que ocorrem no plano horizontal do pasto.Palavras-chave: Brachiaria decumbens, perda de forragem, pastejo, estrutura horizontal do pasto.

Intensive Production and Management of Marandu Palisadegrass (Urochloa brizantha ‘Marandu’) Accelerates Leaf Turnover but Does Not Change Herbage Mass

“…The lack of difference in leaf senescence (average of 0.16 mm per leaves day −1 ) among the pasture intensification systems was expected because it is not affected by leaf defoliation but rather by environmental characteristics, especially water deficits [23], which were not observed during the two collection cycles (Table 1).…”

<b>Defoliation patterns and tillering dynamics in Italian ryegrass under different herbage allowances

“…Defoliation patterns can be studied by evaluating the intensity and frequency of defoliation in individual tillers (SANTOS et al, 2013), and are essential to understanding the effect of grazing on plant and animal performance. Knowledge of the defoliation process allows management with greater harvesting opportunities and improved efficiency of produced herbage.…”