Autores
J. Narciso Sobrinho, H.B. de Mattos, J.B de Andrade, V.B de O. Leite, V.P Martello
Silagem de capim-elefante, em três estádios de maturidade, submetido ao emurchecimento. I- Produção e composição da forragem
Resumo
Foram avaliadas, no Instituto de Zootecnia, SP,, a produção e a composição da matéria seca do capim-elefante (Pennisetum purpureum Schum.), cultivar Guaçu, nas idades de 56, 70 e 84 dias. Na determinação da produção de matéria seca, foram utilizadas 15 parcelas de 27,95 m2, num delineamento inteiramente casualizado, com 5 repetições por tratamento (idades). Para a confecção das silagens. foram usadas 3 parcelas de 490 m2, uma para cada idade. O delineamento foi de blocos casualizados, com 3 repetições e os tratamentos arranjados em fatorial (3 idades X 3 tipos de forragem). As amostras, para avaliar a composição da matéria seca, foram retiradas dos materiais a serem ensilados, em cada uma das repetições dos tratamentos. O capim, dos 2 experimentos, foi rebaixado nas datas de 16/01/97, 30/01/97 e 13/02/97, para obtenção de forragens com 56, 70 e 84 dias de desenvolvimento, no momento do corte para avaliação da matéria seca e para confecção das silagens, em 10/04/97. Cada parcela recebeu 100 kg de N, 80 kg de P2, O5 e 100 de K2,O/ha, utilizando-se sulfato de amônio. superfosfato simples e cloreto de potássio, respectivamente. A produção de matéria seca aumentou linearmente com o aumento do intervalo de corte da forragem. O emurchecimento da forragem aumentou o teor de matéria seca, porém, não alterou a porcentagem de carboidratos solúveis e o poder tampão a ponto de prejudicar a conservação da silagem.
Wilted elephant grass (Pennisetum purpureum Schum.) Silage made from plants cut at three maturity stages. I - Yield and composition of the forages
Abstract
The present study was carried out at Instituto de Zootecnia, SP, in order to evaluate the dry inatter (DM) yield. DM chemical composition of green and wilted herbage, as well as the chemical composition of silages made from green and wilted herbage of elephantgrass (Pennisetum purpureum Sclium.) cv. ‘Guaçu’. To determine DM yield, fifteen 27.95-m2 plots were harvested 10 April at 56, 70, and 84 days of regrowth after mowing on 16 Jan, 30 Jan, and 13 Feb 1997, respectively. Each plot received 100 kg N, 80 kg P2O5, and 100 kg K2O as (NH4)2SO4, simple superphosphate, and KCI, respectively. Nitrogen and potassium were split-applied, one half mowing and the other half 28 days later. The trial was set up in a completely randomized design with five replieations per treatment. Sampling was done by clipping each plot entirely, as the plots were set in the middle ot' the pasture and thus there were no border effects. After weighing, the green herbage was subsampled for determination of DM concentration and yield, weights of leaf and stem fractions plus dead material. The plots used for silage making were staged on the same dates and received the same fertilization. Silages were made from both fresh and wilted herbage, whole and chopped plants, with whole plants being dehydrated for 24 h under field conditions. Chopped herbage was wilted in the sun for 4 h on a brick-floored area. Experimental silos were 150-L plastic drums. Before ensiling the material was sampled and sent to the laboratory for determination of chemical composition, soluble carbohydrate concentration, and buffering capacity. Treatments consisted of ali possible combinations of three forage ages (maturities) and three types of forage (thus a 3 x 3 factorial). Dry matter yield increase with regrowth interval, with the best leaf:stem ratio obseved at 70 days. The wilting methods raised DM concentration satisfactorily and did not reduce soluble carbohydrate concentrations to the point where lactic fermentation was compromised.
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