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Previous issue date: 2016-08-19 / CAPES / The search for the best efficiency in the nitrogen fertilization justifies the need in the evaluation in nitrogen (N) sources and doses what promote lower losses in the ambient, beyond higher productivity and quality of the forage produced. In that contest, this study aimed to evaluation the morphological composition, structural characteristics and nutritional value of the Panicum maximum cv. Massai forage, cultivated under urea sources (common and coated Policote?) and N doses (200, 400 e 600 kg ha-1 year-1), during autumn, winter and spring 2014, summer and autumn 2015 seasons. The experiment was conducted in UFRRJ, Serop?dica/RJ, under a complete block randomized design with four replications in a factorial arrangement (3x2) + 1. The variance analysis of data was performed using the PROC MIXED of the SAS? (9.2 version), a 5% probability. The means of treatments were compared using PDIFF (p<0.05), and the quantitative effects using a PROC REG of SAS? (probability<0.05). There was interaction (p<0.05) between doses, sources of urea, and seasons for the forage mass (FM), percentages of leaf blades (LBDMP), stem (SDMP) and dead material (DMDMP) dry matter, leaves blades: steams ratio (LBSR), forage accumulation rate (FAR), nitrogen use efficiency (NUE), and for dry matter (DM) and crude protein (CP) content of the forage. Since the canopy height (CH), tiller population density (TPD), weight per tiller (WT) and forage bulk density (FBD), mineral matter (MM) and insoluble neutral detergent fiber (NDF) contents of the forage varied (p<0.05) due to N rates and seasons interaction. There was a linear increased in the FM with increasing of N doses until to the 600 kg ha-1 yr-1 level in the winter and spring seasons by both urea sources. The increasing N doses promoted higher LBDMP and lower SDMP and DMDMP of the FM, besides providing increased TPD, FBD and FAR of the massai grass forage, during all seasons studied. There was a quadratic positive effect for NUE during autumn 1, spring, summer and autumn 2 for common and coated urea, with higher maximum points for coated urea. And during the winter there was a positive linear effect only for coated urea. Higher average values of the CP were verified on the spring (11.76%), and lower on the autumn/winter (9.15%), and the use of coated urea providing higher CP levels of the forage than common urea in all seasons (10.40% and 9.41% general average, respectively). The CP content increased linearly with the increase of N levels in all seasons, while the NDF reduced linearly with increasing of these levels, except for the fall season 2 (there was not effect for N dose - p>0.05). Intensification of nitrogen fertilization favors the leaf blades participation in the forage mass, benefiting the structural characteristics, the forage accumulation, and the nutritional value of Massai grass. Coated urea promotes greater NUE during all seasons of the year. / A busca pela melhor efici?ncia da aduba??o nitrogenada justifica a necessidade da avalia??o de fontes e doses de nitrog?nio (N) que promovam menores perdas para o ambiente, al?m de maior produtividade e qualidade da forragem produzida. Nesse contexto, objetivou-se avaliar a composi??o morfol?gica, as caracter?sticas estruturais e o valor nutricional da forragem do Panicum maximum cv. Massai, cultivado sob fontes de ureia (comum e revestida por Policote?) e doses de N (200, 400 e 600 kg ha-1 ano-1), durante as esta??es de outono, inverno e primavera de 2014, ver?o e outono de 2015. O Experimento foi conduzido na UFRRJ, Serop?dica/RJ, sob delineamento de blocos completos casualizados em arranjo fatorial (3x2) + 1, com quatro repeti??es. Para an?lise de vari?ncia dos dados utilizou-se o PROC MIXED do SAS? (vers?o 9.2), a 5% de probabilidade. As m?dias dos tratamentos foram comparadas pela PDIFF (p<0,05), e os efeitos quantitativos pelo PROC REG do SAS? (p<0,05). Houve intera??o (p<0,05) entre doses, fontes de ureia, e esta??es do ano para massa de forragem (MF), porcentagens de massas secas de l?minas foliares (PMSLF), de colmos (PMSC), e de material morto (PMSMM), rela??o l?mina foliar: colmo (RLFC), taxa de ac?mulo de forragem (TAF), efici?ncia da utiliza??o do nitrog?nio (EUN), e para os teores de mat?ria seca (MS) e prote?na bruta (PB) da forragem. J? a altura (ALT) dos doss?is, densidade populacional de perfilhos (DPP), peso por perfilho (PP) e densidade volum?trica da forragem (DVF), bem como os teores de mat?ria mineral (MM) e de fibra em detergente neutro (FDN) da forragem variaram (p<0,05) com a intera??o entre dose de N e esta??o do ano. A MF aumentou linearmente com a aduba??o nitrogenada at? a dose de 600 kg ha-1 ano-1 de N nas esta??es de inverno e primavera para ambas as fontes de ureia. Maiores doses de N promoveram maiores PMSLF e menores PMSC e PMSMM na MF, al?m de proporcionar maiores DPP, DVF e TAF do capim-massai, durante as esta??es estudadas. Houve efeito quadr?tico positivo para EUN durante o outono 1, primavera, ver?o e outono 2 para ureia comum e revestida, com maiores pontos de m?ximo para ureia revestida, e durante o inverno houve efeito linear positivo somente para ureia revestida. Maior valor m?dio de PB foi verificado na primavera (11,76%), e menor no outono/inverno (9,15%), e o uso da ureia revestida promoveu maiores teores de PB na forragem que a ureia comum em todas as esta??es (m?dias gerais de 10,40% e de 9,41%, respectivamente). O teor PB aumentou linearmente com o incremento de doses de N em todas as esta??es, enquanto que os teores de FDN reduziram linearmente com aumento dessas doses, exceto para a esta??o outono 2 (n?o houve efeito de dose de N ? p>0,05). A intensifica??o da aduba??o nitrogenada favorece a participa??o de l?minas foliares na massa de forragem, beneficia as caracter?sticas estruturais, o ac?mulo de forragem, e o valor nutricional do capim-massai. O uso de ureia revestida promove maior EUN durante todas as esta??es do ano.
| Identifer | oai:union.ndltd.org:IBICT/oai:localhost:jspui/1996 |
| Date | 19 August 2016 |
| Creators | SILVA, Aline Barros da |
| Contributors | Carvalho, Carlos Augusto Brand?o de, Carvalho, Carlos Augusto Brand?o de, Oliveira, Ana Paula Pessim de, Campos, F?bio Prud?ncia de |
| Publisher | Universidade Federal Rural do Rio de Janeiro, Programa de P?s-Gradua??o em Zootecnia, UFRRJ, Brasil, Instituto de Zootecnia |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Format | application/pdf |
| Source | reponame:Biblioteca Digital de Teses e Dissertações da UFRRJ, instname:Universidade Federal Rural do Rio de Janeiro, instacron:UFRRJ |
| Rights | info:eu-repo/semantics/openAccess |
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