<b>Crescimento, produtividade, caracterização e composição química da aveia branca</b> - DOI: 10.4025/actascianimsci.v29i1.241 <b>Growth, productivity, characterization and chemical composition of white oat</b> - DOI: 10.4025/actascianimsci.v29i1.241

Foi conduzido um experimento na Escola Superior de Agricultura Luiz de Queiroz, Piracicaba, Estado de São Paulo, para avaliar o crescimento, produtividade, características morfológicas e fenológicas e a composição química da aveia branca (<em>Avena sativa</em> L. cv. UPF 7). Os tratamentos constaram de épocas de cortes a cada 14 dias, dispostos ao acaso, com três repetições. O acúmulo de matéria seca (MS) apresentou efeito quadrático, atingindo 12.240 kg ha^-1 na maturação. O acúmulo máximo de proteína bruta (PB) ocorreu 98 dias após a emergência (DAE) (818 kg ha^-1), sendo que o teor de PB e a digestibilidade <em>in vitro</em> da MS (DIVMS) decresceram de 24,9% e 82,2% aos 14 DAE para 4,9% e 36,8% na maturação, respectivamente. Aos 70 DAE a DIVMS foi de 68%, com rendimento de 3.693 kg ha^-1 de MS, altura de plantas de 63 cm e teores de 18,9% de PB, 0,28% de Ca e 0,37% de P. A disponibilidade ótima de forragem para alimentação animal (1.500 kg MS ha^-1) foi estimada para 37 DAE, com as plantas apresentando altura de 33 cm, 21,4% de PB, 0,4% de P, 0,27% de Ca e uma DIVMS de 75,5%. A época indicada para utilização da aveia, considerando a disponibilidade de forragem e a DIVMS está entre 37 e 70 DAE.<br>One experiment was carried out at Escola Superior de Agricultura Luiz de Queiroz, Piracicaba, State of São Paulo, with the purpose of evaluating growth, productivity, morphological and phenological characteristics and chemical composition of white oat (<em>Avena sativa</em> L. cv. UPF 7). The treatments were conducted during cutting times each 14 days, in a random design with three replications. A quadratic effect of time was observed on dry matter and crude protein accumulation, reaching maximum values at maturation (12,240 kg ha^-1) and at 98 days after emergence (DAE) (818 kg ha^-1), respectively. Crude protein concentration and <em>in vitro</em> dry matter digestibility (IVDMD) decreased with the time from 24.9 and 82.2% at 14 DAE to 4.9 and 36.8% at maturation, respectively. At 70 DAE, IVDMD was 68%, dry matter production was 3693 kg ha^-1, plants height was 63 cm, CP, Ca and P were 18.9, 0.28 and 0.37% respectively. The optimum availability of forage estimated for 37 DAE through polynomial regression was 1,500 kg ha^-1 (dry matter production), and at this time the forage showed the following characteristics: height of 33 cm, 21.4% CP, 0.4% P, 0.27% Ca and 75.5% IVDMD. The time suggested for the utilization of this forage, according to the values of IVDMD and availability of forage varied from 37 to 70 DAE

Canopy height impact on legume mass and Megathyrsus maximus tiller dynamics in mixed pastures

The use of grazing management strategies can influence canopy structure and the permanence of legumes. The objective of this work was to evaluate the determination of forage canopy heights as a grazing management strategy regarding herbage mass composition and tiller population dynamics in multispecies pastures comprising Megathyrsus maximus cv. Aruana and the legumes Macrotyloma axillare, Calopogonium mucunoides and Stylosanthes spp. Four treatments, defined by canopy heights of 15, 30, 45 and 60 cm, were evaluated in a randomised block design with four replications. The evaluations were performed under continuous stocking with sheep. Taller pastures (45 and 60 cm) contained greater (P < 0.05) total herbage mass of Aruana leaves and stems and also higher mass of legumes than smaller pastures (15 and 30 cm). The grass tiller population density was different between heights (P < 0.05) of 2.71, 2.02, 1.97 and 1.47 tillers/m2 for heights of 15, 30, 45 and 60 cm, respectively. The tiller appearance rate was highest in tall pastures (P < 0.05) and the lowest rate and stability index were found in 15 cm pastures. Aruana guineagrass and forage legumes can be managed in the height range of 30–60 cm under continuous stocking