Sistema silvipastoril com eucalipto: produtividade do sub-bosque e desempenho de novilhos sob fertilização nitrogenada e potássica

• Ano de defesa: 2007
• Autor(a) principal: Bernardino, Fernando Salgado
• Orientador(a): Garcia, Rasmo
• Banca de defesa: Paulino, Mário Fonseca , Queiroz, Domingos Sávio
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Doutorado em Zootecnia
• Departamento: Genética e Melhoramento de Animais Domésticos; Nutrição e Alimentação Animal; Pastagens e Forragicul
• País: BR
• Palavras-chave em Português: Luminosidade; Sub-bosque; Qualidade
• Palavras-chave em Inglês: Luminosity; Understory; Quality
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::ZOOTECNIA::PASTAGEM E FORRAGICULTURA
• Link de acesso: http://locus.ufv.br/handle/123456789/1910

The study was conducted to evaluate silvopastoral understory dry matter production, chemical composition, and the animal performance under different nitrogen and potassium fertilization and forage offers. Three experiments were conducted at Riacho Farm, located in the region of Paracatu, Minas Gerais Brazil, in a silvopastoral system constituted by eucalyptus and Brachiaria brizantha cv. Marandu. In the first experiment, the understory dry matter production and chemical composition were evaluated in response to three N levels (0, 75 and 150 kg ha-1) and two K2O levels (0 and 100 kg ha-1), in a completely random design. Nitrogen levels increased dry matter production and accumulation rate. Potassium fertilization increased the N effect, potentializing N effects. Fertilizers increased plant N accumulation rates whereas K accumulation rates were influenced by N plus K treatments. Neutral detergent fiber (NDF) percents were not affected by treatments. The second experiment was conducted to evaluate animal performance, grazing silvopastoral understory fertilized with N and K, with same levels used in first experiment. The individual liveweight gain (LWG) was influenced by N levels, which showed linear increase in first period, quadratic variation on second period, and linear decrease on third period. The variations on LWG did not compromise liveweight gain per hectare. Higher N levels, combined with K, resulted in higher liveweight gain per hectare. The third experiment was conducted to evaluate animal performance, grazing silvopastoral understory fertilized with N (0, 75 and 150 kg ha-1), combined with two forage offers (10 and 15% bodyweight). The N levels increased LWG only on first evaluation period, but resulted in higher liveweight gain per hectare. The forage offer did not affect LWG. The experiments results evidenced that N and K fertilization increase dry matter production and the stocking rate, but did not compromise nutrient availability to the animals. LWG per hectare increases in consequence of fertilization. Forage offer of 15% is adequate when lower levels of N are applied on understory. For higher N levels, the forage offer of 10% results in higher LWG per hectare. Understory fertilization is efficient and necessary to intensifying silvopastoral systems.