Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2017-09-15T18:57:49Z No. of bitstreams: 1 2014 - Ana Carolina Carvalho de Barros.pdf: 2646968 bytes, checksum: 755045d3111f54dc02cc0c3c6834d0c5 (MD5) / Made available in DSpace on 2017-09-15T18:57:49Z (GMT). No. of bitstreams: 1 2014 - Ana Carolina Carvalho de Barros.pdf: 2646968 bytes, checksum: 755045d3111f54dc02cc0c3c6834d0c5 (MD5) Previous issue date: 2014-09-22 / CAPES / This study was carried out for evaluating the dynamics of the root dry matter stock in Florico grass pastures managed at two light interception levels (90 and 95%) and two post-grazing residue heights (0.2 and 0.3 m) (90IL 0,2m RPP; 90IL 0,3m RPP; 95IL 0,2m RPP; 95IL 0,3m RPP). The lowering of vegetation was performed by the technique "mob grazing", simulating the condition of intermittent grazing. In shoot mass were related (MFF and MF) and the rate of herbage accumulation (TAMFF and TAF) with varying root system, using the technique of digging trenches 0,5x0,4x0,6 me withdraw prism?sticos blocks per monoliths 0,05x0,2x0,1 m up to 0.4 m profundida for root stock and fractional distribution (DF), and the root / shoot ratio, and total biomass (FT). The experiment was performed at PESAGRO-RIO, in Serop?dica municipality, Rio de Janeiro state , from July, 2012 to July, 2013, covering the four seasons. Shoots fresh matter yield was effective for treatment, season, and repeated measures interaction, with total production in the summer of 2013 for the four grazing intensities (908.1 ? 73.8 g/m2), compared to other seasons where treatments were similar. In the season of different days between cycles, shoots fresh matter yield was estimated where the winter, presented the lowest yield (10.8 ? 5.1 g/m2 day 1), when compared to the rainy season (28,7 ? 13.1 g/m2 day 1), as well as, between the treatments, the highest grazing intensity presented the greatest yield (26.6 ? 15.8 g/m2 day 1) while the lowest one presented the smallest yields (13.6 ? 4.1 g/m2 day 1). Shoots dry matter yield indicated high significant effects for treatments, season, and interaction for repeated measurements over time between treatments the 90IL 0,3RPP treatment presented no difference in relation to shoot dry matter among seasons, whereas 95IL 0,3RPP treatment presented greater shoot dry matter quantity in the spring (219.8 g/m2 cycle 1), followed by summer (192.2 g/m2 cycle 1), as well as, in the autumn 90IL 0,3RPP treatment was more productive than 95IL 0,3RPP one. Shoot dry matter yield was lower in all the treatments in the winter when compared to the other seasons, the greatest roots dry matter (RDM) were: 639.3 ? 246.8 and 667.2 ? 225.7 g 400dm3 soil in the spring, for 90IL 0,3RPP and 95IL 0.3 RPP, respectively and 591.8 ? 168.2 and 655.1 ? 252.7g 400 dm3 soil in the summer anol autumn, for 90IL 0.2RPP respectively 647.8 ? 68.4g 400 dm3 soil in the autumn for 95IL 0,2RPP treatment. In regarding to the roots distribution profile there was no difference between RDM stock treatments between grazing intensities evaluated, summer and autumn equations did not differ eithen. In fractional root distribution all the seasons presented significative results, being autumn the single one no differing between treatments on the present study. Total phytomass presented significantive effect for the treatments, where the winter was the season presenting the lowest yield in all the treatments, when compared to other stations. Root:shoot ratio was no effect for treatment and season, as well as, the autumn highlighted with the greatest RDM:SDM ratio in 95IL 0,2RPP treatment, when compared to the other seasons. It might be concluded that The Florico grass was sensitive to variations in weather conditions presenting to the accumulation of forage and root stock, showing the existence of phenotypic plasticity for the evaluated variables. / Objetivou-se avaliar o estoque de massa seca de raiz em pastos de capim Florico manejados sob dois n?veis de intercepta??o luminosa (90 e 95 %) e duas alturas de res?duo p?s-pastejo (0,2 e 0,3 m), os quais deram origem a quatro tratamentos de intensidades de pastejo (90IL 0,2m RPP; 90IL 0,3m RPP; 95IL 0,2m RPP; 95IL 0,3m RPP). O rebaixamento da vegeta??o foi realizado pela t?cnica ?mob grazing?, simulando a condi??o de pastejo intermitente. Na parte a?rea foram relacionados massa (MFF e MF) e a taxa de ac?mulo de forragem (TAMFF e TAF) com vari?veis do sistema radicular, utilizando a t?cnica de escava??o de trincheiras de 0,5x0,4x0,6 m e retirada de blocos prism?sticos por mon?litos de 0,05x0,2x0,1 m, at? a profundida de 0,4 m para o estoque radicular e distribui??o fracional (DF), al?m da rela??o raiz/parte a?rea e fitomassa total (FT). O experimento foi conduzido na PESAGRO-RIO, em Serop?dica, Rio de Janeiro, de julho de 2012 a julho de 2013, durante quatro esta??es do ano. A massa fresca de forragem variou com tratamento, esta??o do ano e com a intera??o entre eles (p<0,01), apresentando maiores valores no ver?o com 908,1 ? 73,8 g m-2 (m?dias dos quatro tratamentos de pastejo), comparado com as demais esta??es que foram semelhantes entre si. Devido a varia??o existente entre os ciclos de pastejos, em dias, foi calculado a taxa de ac?mulo de forragem de massa seca de forragem, com menor valor obtido no inverno (10,8 ? 5,1 g m-2 dia-1), quando comparado ao per?odo chuvoso (28,7 ? 13,1 g m-2 dia-1). Maior taxa de ac?mulo de forragem massa fresca de forragem foi obtida para o tratamento (90IL 0,2m RPP) de maior intensidade de pastejo (26,6 ? 15,8 g m-2 dia-1) e, menor valor, para aquele (95IL 0,3m RPP) de menor intensidade (13,6 ? 4,1 g m-2 dia-1). A massa seca de forragem n?o variou (p>0,05) entre as esta??es para o tratamento 90IL 0,3m RPP, enquanto que, o tratamento 95IL 0,3RPP, na primavera e ver?o, apresentou maior massa, (219,8 e 192,2 g m-2 ciclo-1), enquanto o tratamento 90IL 0,3RPP foi mais produtivo que o 95IL 0,3RPP no outono. A produ??o de massa seca radicular (MSR) do inverno foi inferior aquelas das demais esta??es. Na primavera, os maiores estoques de MSR foi de: 639,3 ? 246,8 e 667,2 ? 225,7 g 400dm3 de solo, respectivamente , para 90IL 0,3m RPP e 95IL 0,3m RPP; enquanto que o tratamento 90IL 0,2m RPP apresentou maiores estoques de MSR: 591,8 ? 168,2 e 655,1 ? 252,7 g 400dm3 de solo-1, respectivamente no ver?o e outono e o tratamento 95IL 0,2m RPP estocou maiores quantidades de MSR no outono (647,8 ? 68,4 g 400dm3 de solo-1). Quanto a distribui??o das ra?zes no perfil, houve diferen?a do estoque de MSR entre tratamentos na primavera e, as equa??es do ver?o e outono n?o diferiram entre si. A distribui??o fracional do sistema radicular variou (p<0,05) entre todas as esta??es, por?m no outono, houve semelhan?a entre os tratamentos. A produ??o de fitomassa total variou (p<0,05) entre os tratamentos, com a menor produ??o no inverno, para os tratamentos. A rela??o raiz: parte a?rea variou (p<0,05) com tratamento e esta??o. Para 95IL 0,2m RPP, maior valor foi obtido no outono. O capim Florico foi sens?vel ?s condi??es clim?ticas apresentando varia??es quanto ao ac?mulo de forragem e estoque radicular, evidenciando a exist?ncia de plasticidade fenot?pica para as vari?veis avaliadas.

Made available in DSpace on 2016-04-26T19:39:33Z (GMT). No. of bitstreams: 1 2007 - Sergio Trabali Camargo Filho.pdf: 4423367 bytes, checksum: 827592ba3f6a9d37da8d784b6ae6ffe8 (MD5) Previous issue date: 2009-12-18 / The environmental conditions of light, temperature and water availability, along with grazing, are major factors establishing growth and phenology of forage species. The climatic effects imprint dynamics specific to pasture ecosystems, which are generally referred as "seasonality of the pasture." This study was set in an area of Fragiudult soil, located in Serop?dica municipality, Rio de Janeiro State, Brazil. The experiment began with a cut to make uniform the pasture at the height of 0.05 m, in February 2002. The aim was to determine the influence of climatic and genotypes factors in the expression of features of production, also the partition of carbon and nutrients in the aerial and ground parts of the perennial grasses Cynodon nlemfuensis (stargrass Puerto Rico); Cynodon spp (Tifton-85 grass); Digitaria swazilandensis (swazi grass) and Digitaria decumbens cv. Transvala (Transvala grass). Two hypotheses were formulated to guide the study: i) in the drier periods of the year, the fodder allocate more carbon and nutrients in roots than in the aerial parts of the plants; ii) the species have more or less plasticity to respond to seasonal climatic fluctuations, and periodic defoliation, evidencing differential adaptive capabilities. To check these possibilities, it was used a simple strategy trial, where, from the cut for uniformity, there were evaluated eight periods, between 03/26/02 and 01/14/03, at intervals of 42 days, sampling material of aerial and root fitomass. After processing the samples, the fresh and air dry mass were determined (kg ha-1). In the root system, the accumulation and distribution of dry weight, and the length and surface area of roots to the depth of 1.0 m were determined, by sequential extraction of monoliths (1.0 dm3) from the wall of a soil trench. In sub-samples of dried and grinded aerial parts and roots, the levels of nitrogen, phosphorus, calcium and magnesium (g kg-1) were quantified. The results showed that: regardless of forage species, the root:shoot ratio (based on dry fitomass in standing fluctuated seasonally, with higher values in the dryer months of the year, and smaller in the months of highest rainfall; the species varied in their responses, evidencing the existence of phenotypic plasticity for attributes of production (accumulation of forage and root mass) and adaptive (length and specific root area), with the Tifton-85 grass outstanding by the level of productivity and stability; the magnitude of the differences between the species was controlled by the water availability, and it was amplified in the periods of increased rainfall and reduced in driest periods. The concentration of nutrients, in aerial and root biomass, responses were varied according to the nutrient, but, in general, the more nutrient concentrated in Digitaria that Cynodon, observation which was also valid for the quality of fiber. Already, the Cynodon accumulated more nutrients that Digitaria per unit area. For the relations of concentrations and accumulation of nutrients roots: shoot had little effect on the grasses and a rule, during dried periods was higher than those of rainfall period. Finally, each grass has its own dynamic in relations soil-plant-atmosphere, showing once again the different adaptive responses of these grasses. / As condi??es ambientais de luz, temperatura, disponibilidade h?drica e de nutrientes, junto com o pastejo, s?o os principais moduladores do crescimento e fenologia das esp?cies forrageiras. Os efeitos clim?ticos imprimem din?micas espec?ficas ao ecossistema pastoril, que s?o geralmente referidas como sazonalidade das pastagens . O presente trabalho foi realizado em uma ?rea de solo Planossolo, localizada no munic?pio de Serop?dica, RJ. O prop?sito foi o de determinar a influ?ncia dos fatores clim?ticos e genot?picos na express?o de caracter?sticas produtivas; assim como na parti??o de carbono e nutrientes entre as por??es a?reas e subterr?neas das gram?neas perenes Cynodon nlemfuensis (capim-Estrela Porto Rico); Cynodon spp (capim-Tifton-85); Digitaria swazilandensis (capim-su?zi) e Digitaria decumbens cv. Transvala (capim-Transvala). Foram formuladas duas hip?teses para orientar o trabalho: i) nos per?odos mais secos do ano, os capins alocam mais carbono e nutrientes nas ra?zes do que na parte a?rea; ii) os capins possuem maior ou menor plasticidade para responder ?s oscila??es clim?ticas sazonais e ? desfolha peri?dicas, evidenciando capacidades adaptativas diferenciais. Para verificar essas possibilidades, usou-se uma estrat?gia experimental simples, onde, a partir do corte de uniformiza??o, foram avaliados oito per?odos de crescimento, entre 26/03/02 e 14/01/03, a intervalos de 42 dias, com amostragens de fitomassa de parte a?rea e radicular. Ap?s processamento das amostras, foram determinadas a massa verde e massa seca da parte a?rea (kg ha-1). No sistema radicular, foram determinados o ac?mulo e a distribui??o da massa seca, al?m do comprimento e ?rea superficial das ra?zes at? a profundidade de 1,0 m, pela extra??o seq?encial de mon?litos (1,0 dm3) a partir da parede de uma trincheira de solo. Em sub-amostras secas e mo?das de parte a?rea e ra?zes foram determinados os teores de nitrog?nio, f?sforo, c?lcio e magn?sio (g kg-1). Os resultados obtidos permitiram observar que: independentemente do capim, a rela??o raiz: parte a?rea oscilou sazonalmente, tendo maiores valores nos meses mais secos do ano e menores nos meses de maior pluviosidade; os capins variaram as suas respostas, evidenciando a exist?ncia de plasticidade fenot?pica para atributos produtivos (ac?mulos de forragem e massa radicular) e adaptativos (comprimento espec?fico e ?rea radicular), tendo o capim-Tifton-85 se sobressa?do pelo n?vel de produtividade e estabilidade; a magnitude das diferen?as entre os capins foi controlada pela disponibilidade de ?gua, sendo amplificada nos per?odos de maior pluviosidade e reduzida nos per?odos mais secos. A concentra??o de nutrientes, tanto da fitomassa a?rea como da fitomassa radicular, tiveram respostas variadas de acordo com o nutriente, mas, de um modo geral, as Digitaria concentraram mais nutrientes que os Cynodon, observa??o que tamb?m foi v?lida para a qualidade da fibra. J?, os Cynodon acumularam mais nutrientes que as Digitaria por unidade de ?rea. Para as rela??es das concentra??es e ac?mulos de nutrientes ra?zes: parte a?rea teve poucos efeitos para os capins e, em geral no per?odo seco foram superiores aos dos per?odos chuvosos. Por fim, cada capim estabeleceu sua pr?pria din?mica nas rela??es solo-planta-atmosfera, evidenciando mais uma vez as diferentes respostas adaptativas destas gram?neas forrageiras.