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21	Estabelecimento de pastagens de tifton 85 sob doses de aduba??o nitrogenada. / Establishment of pastures of tifton 85 under levels of nitrogen fertilization. Galzerano, Leandro 05 August 2008 (has links) Made available in DSpace on 2016-04-28T14:59:45Z (GMT). No. of bitstreams: 1 2008 - Leandro Galzerano.pdf: 1398173 bytes, checksum: 3b9bc8540a1e5f744b54fffefe6a7828 (MD5) Previous issue date: 2008-08-05 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / This work was carried out in order to obtain subsidies under the definition of strategies for nitrogen fertilization of pastures of tifton 85, based on monitoring the dynamics changes in the structure of swards. The underlying assumption was that the application of increasing levels of N is a powerful tool for that purpose. The experiment was developed over a Planosol of occurrence in the experimental field of the Universidade Federal Rural Rio de Janeiro, city of Serop?dica, Brazil, during the establishment of the pasture, between the months of October, 2006 to January 2007. Treatments consisted of four levels of N (0, 50, 100 and 150 kg N-urea. ha-1), in single application, in plots of 4 x 4 m, arranged in blocks fully randomized, with four repetitions. Together with nitrogen fertilization, the plots received 80 kg P.ha-1 and 150 kg K.ha-1, and Ca as calcareo (1.0 tn.ha-1). The variables were: frequency of occurrence of plants; height of the canopy, leaf growth and leaf area index (LAI), the interception of photosynthetically active radiation (PAR) and the production and partition of dry matter. The results showed that the frequency of occurrence, height and interception of PAR varied according to a standard logistic, whose parameters have been modified to a greater or lesser degree, by the levels of N added. Similarly, at the 87 days after planting, the LAI and the total dry matter produced, but not its partition between leaves and stems, responded to changes in N mineral available in the soil. It was concluded that the application of increasing levels of Nurea, during the establishment of grass tifton 85 was an efficient experimental strategy for the induction of quantitative changes during the development time of swards structure. / O presente trabalho foi realizado com o prop?sito de definir estrat?gias de aduba??o nitrogenada em pastagens de tifton 85, baseadas no monitoramento de mudan?as din?micas na estrutura dos doss?is forrageiros. O experimento foi desenvolvido numa ?rea de Planossolo no campo experimental da Universidade Federal Rural do Rio de Janeiro, munic?pio de Serop?dica, RJ, durante a fase de estabelecimento da pastagem, entre os meses de outubro de 2006 a janeiro de 2007. Os tratamentos consistiram de quatro n?veis de N (0; 50; 100 e 150 kg N-ur?ia.ha-1), em aplica??o ?nica, dispostos em parcelas de 4 x 4 m, arranjadas em blocos inteiramente casualizados, com quatro repeti??es. Em conjunto com a aduba??o nitrogenada, as parcelas receberam 80 kg P.ha-1 e 150 kg K.ha-1. O solo foi corrigido com 1,0 tn.ha-1 de calc?reo. As vari?veis estudadas foram: freq??ncia de ocorr?ncia de plantas; altura do dossel, crescimento foliar e ?ndice de ?rea foliar (IAF), intercepta??o de radia??o fotossinteticamente ativa (RFA) e produ??o e parti??o da mat?ria seca. Os resultados obtidos mostraram que a freq??ncia de ocorr?ncia; altura e a intercepta??o de RFA variaram temporalmente de acordo com um padr?o log?stico, cujos par?metros foram modificados, em maior ou menor grau, pelos n?veis de N adicionados. De forma similar, aos 87 dias p?s- plantio, o IAF e a mat?ria seca total produzida, mas n?o a sua parti??o entre folhas e colmos, responderam ?s varia??es do N mineral dispon?vel no solo. Foi conclu?do que a aplica??o de n?veis crescentes de Nur?ia, durante a fase de estabelecimento do capim tifton 85 foi uma estrat?gia experimental eficiente para a indu??o de varia??es quantitativas durante o desenvolvimento temporal da estrutura dos doss?is. Cynodon spp frequ?ncia de ocorr?ncia ?ndice de ?rea foliar radia??o fotossinteticamente ativa rela??o folha:colmo mat?ria seca total. Cynodon spp frequency of occurrence leaf area index photosynthetically active radiation leaf: stem ratio total dry matter.
22	Multispectral imaging of Sphagnum canopies: measuring the spectral response of three indicator species to a fluctuating water table at Burns Bog Elves, Andrew 02 May 2022 (has links) Northern Canadian peatlands contain vast deposits of carbon. It is with growing urgency that we seek a better understanding of their assimilative capacity. Assimilative capacity and peat accumulation in raised bogs are linked to primary productivity of resident Sphagnum species. Understanding moisture-mediated photosynthesis of Sphagnum spp. is central to understanding peat production rates. The relationship between depth to water table fluctuation and spectral reflectance of Sphagnum moss was investigated using multispectral imaging at a recovering raised bog on the southwest coast of British Columbia, Canada. Burns Bog is a temperate oceanic ombrotrophic bog. Three ecohydrological indicator species of moss were chosen for monitoring: S. capillifolium, S. papillosum, and S. cuspidatum. Three spectral vegetation indices (SVIs) were used to characterize Sphagnum productivity: the normalized difference vegetation index 660, the chlorophyll index, and the photochemical reflectance index. In terms of spectral sensitivity and the appropriateness of SVIs to species and field setting, we found better performance for the normalized difference vegetation index 660 in the discrimination of moisture mediated species-specific reflectance signals. The role that spatiotemporal scale and spectral mixing can have on reflectance signal fidelity was tested. We were specifically interested in the relationship between changes in the local water table and Sphagnum reflectance response, and whether shifting between close spatial scales can affect the statistical strength of this relationship. We found a loss of statistical significance when shifting from the species-specific cm2 scale to the spectrally mixed dm2 scale. This spatiospectral uncoupling of the moisture mediated reflectance signal has implications for the accuracy and reliability of upscaling from plot based measurements. In terms of species-specific moisture mediated reflectance signals, we were able to effectively discriminate between the three indicator species of Sphagnum along the hummock-to-hollow gradient. We were also able to confirm Sphagnum productivity and growth outside of the vascular growing season, establishing clear patterns of reflectance correlated with changes in the local moisture regime. The strongest relationships for moisture mediated Sphagnum productivity were found in the hummock forming species S. capillifolium. Each indicator Sphagnum spp. of peat has distinct functional traits adapted to its preferred position along the ecohydrological gradient. We also discovered moisture mediated and species-specific reflectance phenologies. These phenospectral characteristics of Sphagnum can inform future monitoring work, including the creation of a regionally specific phenospectral library. It’s recommended that further close scale multispectral monitoring be carried out incorporating more species of moss, as well as invasive and upland species of concern. Pervasive vascular reflectance bias in remote sensing products has implications for the reliability of peatland modelling. Avoiding vascular bias, targeted spectral monitoring of Sphagnum indicator species provides a more reliable measure for the modelling of peatland productivity and carbon assimilation estimates. / Graduate peatland peatland restoration peatland monitoring peatland modelling peat peat moss multispectral multispectral imaging multicamera array multitemporal multiple linear regression linear mixed effects Sphagnum sphagna Sphagnum capillifolium Sphagnum papillosum Sphagnum cuspidatum spatiospectral uncoupling near-sensing remote sensing phenospectral phenology phenologies phenospectral bias phenospectral libraries carbon assimilation carbon dioxide carbon dynamics carbon emissions carbon geographies carbon mineralization carbon sequestration carbon source carbon sink carbon storage irrecoverable carbon climate forcing methane Ecological Restoration restoration ecology ecohydrology ecohydrological restoration hydrology ecohydrological gradients ecological integrity reflectance nature based solutions ombrotrophic moss raised peatland mires mires photochemical reflectance index normalized difference vegetation index chlorophyll index climate change climate forcing climate envelope climatope nonvascular vascular bias plant functional type plant functional types structure equation models spectral vegetation indices hummock hollow acrotelm catotelm diplotelmic biocrusts organic soil periodicity moisture deficit senescence rejuvenescence productivity photosynthesis light use efficiency photosynthetic function photosynthetically active radiation water table hydrology rewetting depth to water table landscape change landscape degradation peat subsidence Burns Bog

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Estabelecimento de pastagens de tifton 85 sob doses de aduba??o nitrogenada. / Establishment of pastures of tifton 85 under levels of nitrogen fertilization.

Multispectral imaging of Sphagnum canopies: measuring the spectral response of three indicator species to a fluctuating water table at Burns Bog