Dinâmica de carbono e nitrogênio em pastos de capim-xaraés submetidos a diferentes resíduos pós-pastejo
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Data
2013-02-25
Autores
Raposo, Elisamara [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
O índice de área foliar residual (IAFr) é importante ferramenta no manejo das pastagens, mas pouco se sabe sobre sua influência nas características físicas, químicas e biológicas do solo, além da contribuição para os estoques de carbono e nitrogênio do solo. O experimento teve por objetivo quantificar o estoque de carbono e nitrogênio, a emissão de CO2 e a decomposição da serrapilheira de pastos de capim-xaraés submetidos a diferentes resíduos pós- pastejo nas condições edafoclimáticas de Jaboticabal, SP. A área total de capim-xaraés era de 2.795,9 m², formada em dezembro de 2004 e foi dividida em 12 piquetes para alocação do experimento. Os tratamentos consistiram de quatro resíduos póspastejo, definidos por índice de área foliar residual (IAFr = 0,8; 1,3; 1;8 e 2,3). O IAFr foi estimado com auxílio do aparelho analisador de dossel – AccuPAR Linear PAR/LAI ceptometer da Decagon. A entrada dos animais nos piquetes de pastejo ocorreu quando o dossel atingiu 95% de interceptação de luz (IL) e a saída sempre que o IAFr pré determinado fosse atingido. As avaliações de estoque de carbono e nitrogênio no solo foram realizadas na profundidade de 0 a 30 cm, com três repetições em cada área. Os estoques de carbono e nitrogênio foram calculados com base na massa de solo equivalente. As medidas de emissão de CO2 foram realizadas semanalmente utilizando-se o aparelho de câmara de fluxo LI-COR (LI- 8100). As avaliações das atividades enzimáticas do solo foram feitas a cada 30 dias na profundidade de 0-20 cm durante os meses de janeiro a outubro de 2011, e nestas amostras, foram realizadas as determinações da: atividade das proteases, arilsulfatases, celulases e desidrogenases. A avaliação da decomposição da serrapilheira seguiu a técnica de sacos de “nylon”, sendo incubados por 0, 4, 8, 16, 32, 64, 128 e 256 dias...
Residual leaf area index (LAIr) is an important tool in pasture management, but little is known about its influence on physical, chemical and biological soil properties, in addition to the contribution to carbon and nitrogen stocks in the soil. The experiment aimed to quantify carbon and nitrogen stocks in the soil, CO2 emissions and litter decomposition in Xaraés grass pastures under different post-grazing residues in environmental conditions of Jaboticabal, SP. Total area of Xaraés grass was 2795,9 m², formed in December 2004 and was divided into 12 paddocks for experiment allocation. The treatments consisted of four post-grazing residues, defined by residual leaf area index (LAIr = 0,8, 1,3, 1,8 and 2,3). LAIr was estimated with aid of canopy analyzer equipment - AccuPAR Linear PAR / LAI ceptometer the Decagon. The animals starting grazing in the paddocks when the canopy reached 95% light interception (LI) and the end of grazing occurred when the LAIr predetermined was reached. Evaluations of carbon and nitrogen stocks in soil were realized at depth 0 to 30 cm, with three replications in each area. Carbon and nitrogen stock were calculated based on the equivalent soil mass. Measurements of CO2 emissions were performed weekly using an equipment flow chamber LI-COR (LI-8100). Evaluations of soil enzymatic activities were made every 30 days at a depth of 0-20 cm during ten months (January to October 2011), and these samples were analyzed: proteases, arylsulfatases, cellulases and dehydrogenases activity. Evaluation of litter decomposition followed the litter bag technique and incubated for 0, 4, 8, 16, 32, 64, 128 and 256 days. Dry matter (DM), organic matter (OM), nitrogen (N), phosphorus (P) and carbon (C) contents was determined and calculated the C: N ratio in the remaining material. Soil C and N contents, soil C: N ratio, and C and N stocks in the soil were different... (Complete abstract click electronic access below)
Residual leaf area index (LAIr) is an important tool in pasture management, but little is known about its influence on physical, chemical and biological soil properties, in addition to the contribution to carbon and nitrogen stocks in the soil. The experiment aimed to quantify carbon and nitrogen stocks in the soil, CO2 emissions and litter decomposition in Xaraés grass pastures under different post-grazing residues in environmental conditions of Jaboticabal, SP. Total area of Xaraés grass was 2795,9 m², formed in December 2004 and was divided into 12 paddocks for experiment allocation. The treatments consisted of four post-grazing residues, defined by residual leaf area index (LAIr = 0,8, 1,3, 1,8 and 2,3). LAIr was estimated with aid of canopy analyzer equipment - AccuPAR Linear PAR / LAI ceptometer the Decagon. The animals starting grazing in the paddocks when the canopy reached 95% light interception (LI) and the end of grazing occurred when the LAIr predetermined was reached. Evaluations of carbon and nitrogen stocks in soil were realized at depth 0 to 30 cm, with three replications in each area. Carbon and nitrogen stock were calculated based on the equivalent soil mass. Measurements of CO2 emissions were performed weekly using an equipment flow chamber LI-COR (LI-8100). Evaluations of soil enzymatic activities were made every 30 days at a depth of 0-20 cm during ten months (January to October 2011), and these samples were analyzed: proteases, arylsulfatases, cellulases and dehydrogenases activity. Evaluation of litter decomposition followed the litter bag technique and incubated for 0, 4, 8, 16, 32, 64, 128 and 256 days. Dry matter (DM), organic matter (OM), nitrogen (N), phosphorus (P) and carbon (C) contents was determined and calculated the C: N ratio in the remaining material. Soil C and N contents, soil C: N ratio, and C and N stocks in the soil were different... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Carbono, Nutrientes, Nitrogênio, Pastagens, Resíduo, Waste products
Como citar
RAPOSO, Elisamara. Dinâmica de carbono e nitrogênio em pastos de capim-xaraés submetidos a diferentes resíduos pós-pastejo. 2013. xvi, 69 p. Dissertação (mestrado) - Universidade Estadual Paulista Júlio de Mesquita Filho, Faculdade de Ciências Agrárias e Veterinárias, 2013.