ABSTRACT. Signalgrass structure during pasture deferment. This experiment was performed aiming to evaluate tiller population density, forage mass and its morphological components on pastures of Brachiaria decumbens cv. Basilisk. during deferment. The treatments encompassed four deferred grazing periods (18, 46, 74 and 121 days). A randomized block design with two replications was used. The numbers of vegetative tillers (VT), reproductive tillers (RT) and dead tillers (DT) in the pasture were determined. The masses of green leaf blade (GLBM), dead stem (DSM) and dead forage (DFM) were also determined. There was a reduction in the number of VT (from 1,491 to 944 tiller m -2 ) during the deferment period. RT and DT numbers were not influenced by the deferment periods. Their averages were 211 and 456 tiller m -2 , respectively. Longer deferring periods resulted in an increase in GSM (from 2,965 to 4,877 kg ha -1 of dry mass) and DFM (from 2,324 to 4,823 kg ha -1 of dry mass), but it did not influence GLBM (average of 2,047 kg ha -1 of dry mass). In Viçosa, Minas Gerais State, Brazil, Brachiaria decumbens cv. Basilisk pasture fertilized and deferred in the beginning of March must be kept deferred for about 70 days in order to conciliate both quality and quantity forage production.

No abstract

Brachiaria brizantha is a forage species widely used in Brazilian pastures and its seeds have contamination in several areas of countries. Its high germination is fundamental in pasture formation. However, it is common for seeds of this species to have natural dormancy, negatively influencing pasture formation, resulting in losses to the producer. Thus, the objective of this study was to determine a methodology to overcome dormancy of ‘Marandu’ and ‘Piatã’ B. brizantha seeds. Four batches from the 2016/2017 and 2017/2018 harvests were used. Initially, batch profile was evaluated by the following characteristics: determination of moisture content, weight of a thousand seeds, first germination count, germination, germination speed index, initial stand, emergency, emergency speed index and fungi incidence in seeds. The seeds were subjected to the following treatments to overcome dormancy: mechanical (removal of glume, palea and lemma), sulfuric acid (98%, 36 N), potassium nitrate (0.2%), heat treatment (70 °C and 85 °C, during 5h, 10h, 15h and 20h) and a control. The obtained results allow inferring that the causes of dormancy of ‘Piatã’ seeds are of a physical nature, with the tissues surrounding the seed being the main factor that prevent germination. The mechanical method and scarification with sulfuric acid the most efficient in overcoming dormancy. The mechanical treatment with removal of the glumella is efficient to overcome the dormancy ofB. brizantha seeds, providing an increase in the germination percentage

A ensilagem é uma técnica de conservação de forragens em épocas de favorabilidade pluviométrica para que as silagens produzidas possam ser ofertadas em períodos de escassez de chuvas, em que o crescimento e a produtividade das forrageiras ficam comprometidos. Essa técnica é uma alternativa para mitigar os efeitos da estacionalidade de produção forrageira na produção animal. Todavia, a falta de planejamento correto pode dificultar o uso da técnica e/ou desperdiçar material forrageiro com grande potencial de uso. A realocação de silagem visa armazenar novamente a forragem sem que haja grandes prejuízos à qualidade do material. Nesse sentido, objetivou-se realizar um estudo sistemático sobre a movimentação de silagem de um local para outro e suas implicações na qualidade do produto final. Consideraram-se informações sobre os parâmetros que interferem na qualidade da silagem realocada, como o tipo de material a ser ensilado, a sua composição nutricional, parâmetros fermentativos e estabilidade aeróbica das silagens realocadas. Tais características estão diretamente relacionadas à técnica de ensilagem, ou seja, caso alguma das etapas não seja bem executada, a qualidade da silagem será comprometida e o processo de realocação também será prejudicado. Através da pesquisa realizada, verificou-se que silagens realocadas e armazenadas durante maior período tendem à redução do seu valor nutritivo. O material realocado tende à perda da estabilidade aeróbica devido à degradação de nutrientes ocasionada pelo contato com o oxigênio. Em adição, o período de armazenamento após a realocação é a variável que mais influencia as perdas nutricionais das silagens realocadas.

The objective of this work was to evaluate the morphogenetic, structural, physiological, and productive traits of forage peanut (Arachis pintoi) subjected to different levels of artificial shading in the field. The 'Amarillo MG-100' forage peanut was planted in April 2015, and the evaluations were carried out from May 2017 to April 2018. The treatments were: 0, 30, 45, and 75% of artificial shading. There was no significant effect of shading on the morphogenetic traits of forage peanut. Shading increased final leaf length and canopy height and decreased the leaf area index and number of stolons. Photosynthesis, transpiration rate, stomatal conductance, chlorophyll b, and leaf temperature increased quadratically as a function of shading. There was a linear positive effect on the growing cycle length and a quadratic effect on the production of dry matter mass, with the maximum at 30% shade. Forage peanut harvested at 95% light interception (11-cm height) shows adaptation to shading up to 45%, with increased leaf size, canopy height, photosynthetic rate, stomatal conductance, transpiration rate, and chlorophyll b. In addition, plants at 30% shading show a higher yield than those growing under full sun.