Componentes da Produção de Forragem em Pastagens dos Capins Tanzânia e Mombaça Adubadas com Quatro Doses de NPK
Data
2002-06-01
Autores
Quadros, Danilo Gusmão de [UNESP]
Rodrigues, Luís Roberto de Andrade [UNESP]
Favoretto, Vanildo [UNESP]
Malheiros, Euclides Braga [UNESP]
Herling, Valdo Rodrigues
Ramos, Allan Kardec Braga
Título da Revista
ISSN da Revista
Título de Volume
Editor
Sociedade Brasileira de Zootecnia
Resumo
O trabalho foi conduzido na FCAV-Unesp, em Jaboticabal-SP, para avaliar os efeitos de quatro doses combinadas de NPK sobre os componentes da produção e das perdas de matéria seca (MS) em pastagens dos cultivares Tanzânia e Mombaça de Panicum maximum Jacq., manejadas com 28 dias de descanso e com altura média de 30 cm de resíduo pós-pastejo. As avaliações foram realizadas em parcelas de 96 m² segundo um fatorial 2 (cultivares) x 4 (doses de NPK), em blocos completos ao acaso, com três repetições. As adubações estudadas corresponderam ao decréscimo em 30 % e aos acréscimos em 30 e 60 % de uma dose padrão com 145; 21,6 e 180 kg/ha de N, P2O5 e K2O, respectivamente (referente a 1,2; a 0,08; e a 1,2 % de N, P e K na MS, com produção estimada em 12000 kg/ha). A MS verde (MSV) em pré-pastejo e no resíduo aumentou linearmente com a adubação, com maiores valores obtidos para o cv. Mombaça (9183 e 5227 kg/ha, respectivamente) do que para o cv. Tanzânia (6275 e 3808 kg/ha, respectivamente). A participação de lâminas foliares na MSV em pré-pastejo foi menor no cv. Tanzânia (51 %) do que no cv. Mombaça (54 %). A densidade de perfilhos não variou com a adubação. O aumento do peso de perfilho com a elevação das doses de NPK resultou em maiores produções de MSV. A MS senescida (média de 3108 kg/ha de MS) não diferiu entre cultivares. de modo geral, quanto maior a dose de adubo aplicado, maiores foram a taxa de acúmulo diário de MSV e a MSV perdida por pisoteio. O cv. Mombaça apresentou maior potencial de resposta à adubação do que o cv. Tanzânia, com taxas de lotação de 6,2 e 4,0 UA/ha, respectivamente.
The experiment was conducted at the FCAV-Unesp, Jaboticabal-SP, to evaluate the effects of the fertilization with four doses of NPK on the components of dry matter (DM) and losses by trampling of two cultivars of Panicum maximum Jacq. (Tanzania and Mombaça) under grazing, having a rest period of 28 days and an average height of residue of 30 cm. A complete randomized block design was used with treatments arranged in a 2 x 4 factorial with three field replications. The fertilization doses corresponded to the reduction of 30 % and the increase of 30 and 60% in relation to a standard dose of 145; 21.6; and 180 kg/ha of N, P2O5, and K2O, respectively (assuming the contents of 1.2, 0.08, and 1.2% of N, P, and K in DM, to reach an estimated DM production of 12000 kg/ha). There was a linear effect of fertilization doses on green DM (GDM) before and after grazing. The cv. Mombaça exhibited higher herbage mass before and after grazing (9183 and 5279 kg/ha of GDM, respectively) than the cv. Tanzania (6275 and 3808 kg/ha of GDM, respectively). The proportion of leaf blade in the GDM available was lower in the cv. Tanzania (51%) than in the cv. Mombaça (54 %). The tiller density was not affected by the fertilization doses. However, the increase in tiller weight due to fertilizer doses was responsible for the higher GDM production. The senesced DM did not vary between cultivars, with a mean value of 3108 kg/ha. In general, higher rates of fertilization resulted in greater GDM accumulation rate and higher losses of GDM by trampling. The cv. Mombaça showed a greater response potential to fertilization than the cv. Tanzania with stocking rates of 6.2 and 4.0 UA/ha, respectively.
The experiment was conducted at the FCAV-Unesp, Jaboticabal-SP, to evaluate the effects of the fertilization with four doses of NPK on the components of dry matter (DM) and losses by trampling of two cultivars of Panicum maximum Jacq. (Tanzania and Mombaça) under grazing, having a rest period of 28 days and an average height of residue of 30 cm. A complete randomized block design was used with treatments arranged in a 2 x 4 factorial with three field replications. The fertilization doses corresponded to the reduction of 30 % and the increase of 30 and 60% in relation to a standard dose of 145; 21.6; and 180 kg/ha of N, P2O5, and K2O, respectively (assuming the contents of 1.2, 0.08, and 1.2% of N, P, and K in DM, to reach an estimated DM production of 12000 kg/ha). There was a linear effect of fertilization doses on green DM (GDM) before and after grazing. The cv. Mombaça exhibited higher herbage mass before and after grazing (9183 and 5279 kg/ha of GDM, respectively) than the cv. Tanzania (6275 and 3808 kg/ha of GDM, respectively). The proportion of leaf blade in the GDM available was lower in the cv. Tanzania (51%) than in the cv. Mombaça (54 %). The tiller density was not affected by the fertilization doses. However, the increase in tiller weight due to fertilizer doses was responsible for the higher GDM production. The senesced DM did not vary between cultivars, with a mean value of 3108 kg/ha. In general, higher rates of fertilization resulted in greater GDM accumulation rate and higher losses of GDM by trampling. The cv. Mombaça showed a greater response potential to fertilization than the cv. Tanzania with stocking rates of 6.2 and 4.0 UA/ha, respectively.
Descrição
Palavras-chave
adubação de pastagens, Panicum maximum, perdas por pisoteio, taxa de acúmulo de MSV/ha/dia, UA/ha, AU/ha, green DM accumulation, DM losses by trampling, Panicum maximum, pasture fertilization
Como citar
Revista Brasileira de Zootecnia. Sociedade Brasileira de Zootecnia, v. 31, n. 3, p. 1333-1342, 2002.