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Please use this identifier to cite or link to this item: https://tede.ufrrj.br/jspui/handle/tede/588
???metadata.dc.type???: Dissertação
Title: Características estruturais, teores de clorofila e suas relações com o nitrogênio foliar e a biomassa em capim-Tifton 85
Other Titles: Structural characteristics, chlorophyll contents and its relationship with leaf nitrogen and biomass in Tifton 85 bermudagrass
???metadata.dc.creator???: BARBIERI JUNIOR, Élio 
???metadata.dc.contributor.advisor1???: Rossiello, Roberto Oscar Pereyra
First advisor-co: Morenz, Mirton José Frota
???metadata.dc.description.resumo???: Dentre as propriedades bioquímicas relacionadas à utilização do nitrogênio (N) pelas plantas, os teores de clorofila ocupam posição de destaque. Por essa razão, e dada a importância que a adubação nitrogenada tem na expressão da produtividade das pastagens, tem sido desenvolvidas metodologias que permitem a determinação do teor de clorofila por procedimentos indiretos e não destrutivos. No intuito de fornecer subsídios para a definição de estratégias de adubação nitrogenada em pastagens de Cynodon spp. cv. Tifton 85 foi instalado um experimento com o propósito primordial de verificar o desempenho de um clorofilômetro comercial. Foi utilizada uma estratégia experimental consistente na indução de três níveis de disponibilidade de N no solo, através de adubação nitrogenada. As hipóteses que guiaram o experimento foram as seguintes: i) níveis diferenciados de N no solo, resultam em teores diferenciados de clorofila em folhas recém emergidas; ii) leituras obtidas com um clorofilômetro guardam relação com os teores foliares das clorofilas; iii) teores de clorofila total relacionam-se com os teores foliares de N; e iv) os indicadores ligados à clorofila foliar guardam relação com a produção de matéria seca. O experimento foi desenvolvido sobre um Planossolo Háplico, no campo experimental da Universidade Federal Rural do Rio de Janeiro, município de Seropédica, RJ, durante o período de julho a dezembro de 2008. O experimento foi disposto segundo um desenho em blocos inteiramente casualizados, com quatro repetições. Os tratamentos, alocados nas parcelas (4x4m), consistiram de três níveis de N (0; 75 e 150kg N-uréia/ha), enquanto que nas sub-parcelas, foram alocadas quatro dias de coletas, contados a partir um corte de uniformização, realizado 131 dias após o plantio do capim. Três das datas de amostragem foram pre-fixadas, aos 8, 16 e 24 dias, enquanto a última foi realizada quando a pastagem atingiu um nível de interceptação de 95% da radiação fotossintéticamente ativa incidente. A dinâmica estrutural foi acompanhada através da mensuração das seguintes variáveis do dossel: altura; densidade populacional de perfilhos; índice de área foliar, índice de cobertura verde, e acúmulo de massa verde seca. As clorofilas a, b, e (a+b), foram quantificadas, sempre em primeiras folhas completamente expandidas de perfilhos de sol, pelo método de Arnon modificado, e indiretamente, com um aparelho ClorofiLOG®. Os teores de N total foram determinados nas mesmas folhas, pelo método de Kjeldhal. Os resultados mostraram que os teores de clorofila a, b e (a+b) diferiram entre doses de N, e dias de amostragem, atingindo diferenças máximas entre as doses de N aos 24 dias após corte. As leituras do clorofilômetro (Índice de Clorofila Falker, ICF) e os teores de N foliar também responderam sensivelmente às doses de N, atinguindo valores máximos aos 16 dias. Nesse mesmo dia, a análise de regressão linear entre os teores de clorofila total e de N total, contra os respectivos valores de ICF resultou em coeficientes de determinação de 0,93 e 0,89 respectivamente. O coeficiente de correlação entre a massa verde seca total e os valores de ICF foi de 0,867. O acúmulo de matéria verde seca total aos 28 dias após o corte relacionouse linearmente com as leituras do clorofilômetro feitas aos 16 dias (r2=0,72), um tipo de resultado promissor em termos de estimativas de disponibilidade de forragem. Como conclusão, os resultados permitiram verificar que os teores de clorofila total presentes na primeira folha totalmente expandida, responderam à aplicação de doses diferenciadas de N e se relacionaram estreitamente com os teores de N foliar. Ambos os atributos foram discriminados de forma precisa pelo clorofilômetro sob avaliação. Este aparelho maximizou o seu desempenho no período onde ocorreram os máximos teores de N foliar, relacionando-se diretamente com a matéria seca acumulada no final do período de rebrota.
Abstract: Among the biochemical properties related to the use of nitrogen (N) for the plants, chlorophyll pigments occupy a relevant position. For that reason, and given the importance of the N fertilization for pasture productivity, it has been developed methodologies that allow determining leaf chlorophyll contents for indirect and non destructive procedures. With the purpose of supplying subsidies for N fertilization management in in pastures of Cynodon spp. cv. Tifton 85 was installed an experiment with purpose of verifying the performance of a commercial chlorophyll meter. The experimental strategy consisted of the induction of three levels of soil N availability, through N fertilization. The working hypotheses were the following ones: i) different soil N availabilities result in differentiated leaf chlorophyll contents in leaves recently emerged and fully expanded; ii) readings obtained with a chlorophyll meter are related with foliar Total chlorophyll contents; iii) chlorophyll contents are related with foliar N concentrations; e iv) chlorophyll content indicators keep relationship with green dry matter production. This study was carried out on a Haplic Planosol at the Experimental Campus of the Rural Federal University of Rio de Janeiro, Seropédica, RJ, during the period of July to December 2008. An entirely randomized block design was used, with four repetitions. Main treatments were allocated in plots (4x4 m) and consisted of three N fertilization levels (0; 75 and 150kg N-uréia). Four sampling dates designed as days from a standardization cut made 131days after planting were allocated in sub-plots. Three of the sampling dates (8, 16 and 24 days) were pre-fixed, while the last was accomplished when the sward interception level of photosynthetically active radiation reached a value of 95%. Structural dynamics was followed by monitoring the following canopy variables: sward height; tiller density, leaf area index, green cover index and green dry mass accumulation. Chlorophylls a, b and (a+b) were measured always in the first fully expanded leaves of sun tillers by the Arnon method with modifications, and indirectly, with the chlorophyll meter ClorofiLOG®. In the same type of leaves, total N content was determined by Kjeldhal routine procedures. Principal results showed that concentrations of chlorophylls a, b and (a + b) in Tifton leaf blades were affected by nitrogen fertilization and sampling dates reaching maximal differences at the 24th day after cut. Chlorophyll meter readings (Falker Chlorophyll Index, FCI) and foliar N contents also responsed very sensibly to N rates, reaching maximal values at the16th day after cut. In the same day, Total chlorophyll contents and Total N leaf contents were also significantly correlated with FCI values, with r2 coefficients of 0,93 and 0,89 respectively. Correlation coefficient between total green dry matter and FCI values was 0,867. Total green dry matter accumulation at the last sampling date and FCI readings at 16th day after cut also resulted significantly related (r2 = 0,72), a promising relation for purposes of forage yield estimation. In conclusion, the obtained results allow affirming that, in Tifton 85, total chlorophyll content present in the first leaf totally expanded is a sensitive marker of soil N availability and therefore of N fertilization needs. Total chlorophyll content through its relationship with leaf N contents may be also a valuable tool for foliar N diagnosis. Both attributes were discriminated properly by the chlorophyll meter under evaluation. This apparatus maximized its performance in the period were happened Among the biochemical properties related to the use of nitrogen (N) for the plants, chlorophyll pigments occupy a relevant position. For that reason, and given the importance of the N fertilization for pasture productivity, it has been developed methodologies that allow determining leaf chlorophyll contents for indirect and non destructive procedures. With the purpose of supplying subsidies for N fertilization management in in pastures of Cynodon spp. cv. Tifton 85 was installed an experiment with purpose of verifying the performance of a commercial chlorophyll meter. The experimental strategy consisted of the induction of three levels of soil N availability, through N fertilization. The working hypotheses were the following ones: i) different soil N availabilities result in differentiated leaf chlorophyll contents in leaves recently emerged and fully expanded; ii) readings obtained with a chlorophyll meter are related with foliar Total chlorophyll contents; iii) chlorophyll contents are related with foliar N concentrations; e iv) chlorophyll content indicators keep relationship with green dry matter production. This study was carried out on a Haplic Planosol at the Experimental Campus of the Rural Federal University of Rio de Janeiro, Seropédica, RJ, during the period of July to December 2008. An entirely randomized block design was used, with four repetitions. Main treatments were allocated in plots (4x4 m) and consisted of three N fertilization levels (0; 75 and 150kg N-uréia). Four sampling dates designed as days from a standardization cut made 131days after planting were allocated in sub-plots. Three of the sampling dates (8, 16 and 24 days) were pre-fixed, while the last was accomplished when the sward interception level of photosynthetically active radiation reached a value of 95%. Structural dynamics was followed by monitoring the following canopy variables: sward height; tiller density, leaf area index, green cover index and green dry mass accumulation. Chlorophylls a, b and (a+b) were measured always in the first fully expanded leaves of sun tillers by the Arnon method with modifications, and indirectly, with the chlorophyll meter ClorofiLOG®. In the same type of leaves, total N content was determined by Kjeldhal routine procedures. Principal results showed that concentrations of chlorophylls a, b and (a + b) in Tifton leaf blades were affected by nitrogen fertilization and sampling dates reaching maximal differences at the 24th day after cut. Chlorophyll meter readings (Falker Chlorophyll Index, FCI) and foliar N contents also responsed very sensibly to N rates, reaching maximal values at the16th day after cut. In the same day, Total chlorophyll contents and Total N leaf contents were also significantly correlated with FCI values, with r2 coefficients of 0,93 and 0,89 respectively. Correlation coefficient between total green dry matter and FCI values was 0,867. Total green dry matter accumulation at the last sampling date and FCI readings at 16th day after cut also resulted significantly related (r2 = 0,72), a promising relation for purposes of forage yield estimation. In conclusion, the obtained results allow affirming that, in Tifton 85, total chlorophyll content present in the first leaf totally expanded is a sensitive marker of soil N availability and therefore of N fertilization needs. Total chlorophyll content through its relationship with leaf N contents may be also a valuable tool for foliar N diagnosis. Both attributes were discriminated properly by the chlorophyll meter under evaluation. This apparatus maximized its performance in the period were happenedAmong the biochemical properties related to the use of nitrogen (N) for the plants, chlorophyll pigments occupy a relevant position. For that reason, and given the importance of the N fertilization for pasture productivity, it has been developed methodologies that allow determining leaf chlorophyll contents for indirect and non destructive procedures. With the purpose of supplying subsidies for N fertilization management in in pastures of Cynodon spp. cv. Tifton 85 was installed an experiment with purpose of verifying the performance of a commercial chlorophyll meter. The experimental strategy consisted of the induction of three levels of soil N availability, through N fertilization. The working hypotheses were the following ones: i) different soil N availabilities result in differentiated leaf chlorophyll contents in leaves recently emerged and fully expanded; ii) readings obtained with a chlorophyll meter are related with foliar Total chlorophyll contents; iii) chlorophyll contents are related with foliar N concentrations; e iv) chlorophyll content indicators keep relationship with green dry matter production. This study was carried out on a Haplic Planosol at the Experimental Campus of the Rural Federal University of Rio de Janeiro, Seropédica, RJ, during the period of July to December 2008. An entirely randomized block design was used, with four repetitions. Main treatments were allocated in plots (4x4 m) and consisted of three N fertilization levels (0; 75 and 150kg N-uréia). Four sampling dates designed as days from a standardization cut made 131days after planting were allocated in sub-plots. Three of the sampling dates (8, 16 and 24 days) were pre-fixed, while the last was accomplished when the sward interception level of photosynthetically active radiation reached a value of 95%. Structural dynamics was followed by monitoring the following canopy variables: sward height; tiller density, leaf area index, green cover index and green dry mass accumulation. Chlorophylls a, b and (a+b) were measured always in the first fully expanded leaves of sun tillers by the Arnon method with modifications, and indirectly, with the chlorophyll meter ClorofiLOG®. In the same type of leaves, total N content was determined by Kjeldhal routine procedures. Principal results showed that concentrations of chlorophylls a, b and (a + b) in Tifton leaf blades were affected by nitrogen fertilization and sampling dates reaching maximal differences at the 24th day after cut. Chlorophyll meter readings (Falker Chlorophyll Index, FCI) and foliar N contents also responsed very sensibly to N rates, reaching maximal values at the16th day after cut. In the same day, Total chlorophyll contents and Total N leaf contents were also significantly correlated with FCI values, with r2 coefficients of 0,93 and 0,89 respectively. Correlation coefficient between total green dry matter and FCI values was 0,867. Total green dry matter accumulation at the last sampling date and FCI readings at 16th day after cut also resulted significantly related (r2 = 0,72), a promising relation for purposes of forage yield estimation. In conclusion, the obtained results allow affirming that, in Tifton 85, total chlorophyll content present in the first leaf totally expanded is a sensitive marker of soil N availability and therefore of N fertilization needs. Total chlorophyll content through its relationship with leaf N contents may be also a valuable tool for foliar N diagnosis. Both attributes were discriminated properly by the chlorophyll meter under evaluation. This apparatus maximized its performance in the period were happened Among the biochemical properties related to the use of nitrogen (N) for the plants, chlorophyll pigments occupy a relevant position. For that reason, and given the importance of the N fertilization for pasture productivity, it has been developed methodologies that allow determining leaf chlorophyll contents for indirect and non destructive procedures. With the purpose of supplying subsidies for N fertilization management in in pastures of Cynodon spp. cv. Tifton 85 was installed an experiment with purpose of verifying the performance of a commercial chlorophyll meter. The experimental strategy consisted of the induction of three levels of soil N availability, through N fertilization. The working hypotheses were the following ones: i) different soil N availabilities result in differentiated leaf chlorophyll contents in leaves recently emerged and fully expanded; ii) readings obtained with a chlorophyll meter are related with foliar Total chlorophyll contents; iii) chlorophyll contents are related with foliar N concentrations; e iv) chlorophyll content indicators keep relationship with green dry matter production. This study was carried out on a Haplic Planosol at the Experimental Campus of the Rural Federal University of Rio de Janeiro, Seropédica, RJ, during the period of July to December 2008. An entirely randomized block design was used, with four repetitions. Main treatments were allocated in plots (4x4 m) and consisted of three N fertilization levels (0; 75 and 150kg N-uréia). Four sampling dates designed as days from a standardization cut made 131days after planting were allocated in sub-plots. Three of the sampling dates (8, 16 and 24 days) were pre-fixed, while the last was accomplished when the sward interception level of photosynthetically active radiation reached a value of 95%. Structural dynamics was followed by monitoring the following canopy variables: sward height; tiller density, leaf area index, green cover index and green dry mass accumulation. Chlorophylls a, b and (a+b) were measured always in the first fully expanded leaves of sun tillers by the Arnon method with modifications, and indirectly, with the chlorophyll meter ClorofiLOG®. In the same type of leaves, total N content was determined by Kjeldhal routine procedures. Principal results showed that concentrations of chlorophylls a, b and (a + b) in Tifton leaf blades were affected by nitrogen fertilization and sampling dates reaching maximal differences at the 24th day after cut. Chlorophyll meter readings (Falker Chlorophyll Index, FCI) and foliar N contents also responsed very sensibly to N rates, reaching maximal values at the16th day after cut. In the same day, Total chlorophyll contents and Total N leaf contents were also significantly correlated with FCI values, with r2 coefficients of 0,93 and 0,89 respectively. Correlation coefficient between total green dry matter and FCI values was 0,867. Total green dry matter accumulation at the last sampling date and FCI readings at 16th day after cut also resulted significantly related (r2 = 0,72), a promising relation for purposes of forage yield estimation. In conclusion, the obtained results allow affirming that, in Tifton 85, total chlorophyll content present in the first leaf totally expanded is a sensitive marker of soil N availability and therefore of N fertilization needs. Total chlorophyll content through its relationship with leaf N contents may be also a valuable tool for foliar N diagnosis. Both attributes were discriminated properly by the chlorophyll meter under evaluation. This apparatus maximized its performance in the period were happened the highest leaf N content and linking directly with final green dry matter accumulation.
Keywords: Cynodon spp.
absorbância foliar
Adubação nitrogenada
Clorofilômetro
foliar absortion
N fertilization
clorophyll meter
???metadata.dc.subject.cnpq???: Zootecnia
Language: por
???metadata.dc.publisher.country???: Brasil
Publisher: Universidade Federal Rural do Rio de Janeiro
???metadata.dc.publisher.initials???: UFRRJ
???metadata.dc.publisher.department???: Instituto de Zootecnia
???metadata.dc.publisher.program???: Curso de Pós-Graduação em Zootecnia
Citation: BARBIERI JUNIOR, Élio. Características estruturais, teores de clorofila e suas relações com o nitrogênio foliar e a biomassa em capim-Tifton 85. 2009. 64 f. Dissertação (Mestrado em Produção Animal). Instituto de Zootecnia, Universidade Federal Rural do Rio de Janeiro, Seropédica, RJ, 2009.
???metadata.dc.rights???: Acesso Aberto
URI: https://tede.ufrrj.br/jspui/handle/tede/588
Issue Date: 20-Feb-2009
Appears in Collections:Mestrado em Zootecnia

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