Ao estimado Professor Francisco Antonio Monteiro, meu reconhecimento pela dedicada orientação, amizade e confiança. Ao Pesquisador da Embrapa Gado de Corte Manuel Claudio Motta Macedo, pelos ensinamentos, incentivo e acolhida desde o início de minha jornada em pesquisa com solos e nutrição de plantas. À Pesquisadora da Embrapa Gado de Corte Valéria Pacheco Batista Euclides, responsável pelo projeto de pesquisa no qual a presente tese foi desenvolvida, pelo apoio e sugestões valiosas durante a coleta das variáveis analisadas. À Embrapa Cerrados e Embrapa Gado de Corte, pelo total apoio e incentivo para a conclusão do presente trabalho. Aos professores do Departamento de Solos e Nutrição de Plantas da ESALQ/USP, em especial aos Professores Antonio Roque Dechen e Quirino Augusto de Camargo Carmello, pelos conhecimentos transmitidos e amizade desenvolvida. Ao Pesquisador da Embrapa Cerrados Antônio Carlos Gomes, pelas sugestões e ajuda na realização das análises estatísticas.
The objective of this research was to examine nutritional and growth attributes of Marandu grass (Brachiaria brizantha cv. Marandu) under nitrogen rates and growth ages. Among the nutrients, nitrogen stand out by its effects in promoting forage yield. The study of growth dynamic and nutrition of Marandu grass is a important tool to promote the production and quality of this forage plant. The experiment was carried out in glasshouse conditions, with nutrient solution using ground quartz as substrate. The experimental design used was a complete randomized block design, with treatments arranged in a 5x6 factorial, with four replications. The Marandu-grass was grown in nitrogen rates of 28, 112, 210, 294 and 378 mg L-1 and it was evaluated at the ages of 21, 28, 35, 42, 49 and 56 days after seedling emergence. The nutrient solution was prepared with a constant NO 3-:NH 4 + proportion of 70%:30% and was replaced once a week after the first growth age. Nitrogen rates and growth ages interaction was significant (P<0.05) for all nutritional and growth attributes of Marandu-grass, with exception for the mean net assimilation rate and specific root length. The nitrogen rates in each growth age showed significant effects (P<0.05) on the x total dry matter yield, roots dry mass, number of tillers, leaf area, root length, root surface area, nitrogen concentration, SPAD value, leaf area ratio and relative growth rate of Marandu grass. Maximum dry matter production was estimated to occur at nitrogen rates between 257 and 304 mg L-1 , depending on plant age. The critical nitrogen concentration determined in the most recently expanded leaf lamina was significantly (P<0.01) influenced by plant ages and ranged from 33.8 to 12.8 g kg-1. SPAD values at the critical nitrogen concentration rates were 45.0; 45.7; 49.5; 50.2; 45.7 and 35.3 for growth periods of 21, 28, 35, 42, 49 and 56 days, respectively.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.