Submitted by Gabriela Lopes (gmachadolopesufpel@gmail.com) on 2017-03-07T18:03:09Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertação 2016.pdf: 2038216 bytes, checksum: 9d1aa99ebad2d28646f13558fbedccad (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2017-03-10T19:54:15Z (GMT) No. of bitstreams: 2 Dissertação 2016.pdf: 2038216 bytes, checksum: 9d1aa99ebad2d28646f13558fbedccad (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-03-10T19:54:15Z (GMT). No. of bitstreams: 2 Dissertação 2016.pdf: 2038216 bytes, checksum: 9d1aa99ebad2d28646f13558fbedccad (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2016-02-18 / O uso de resíduos como fertilizante tais como cinza de casca de arroz (CCA) e lodo de estação de tratamento de esgoto (LETE) podem contribuir no fornecimento de nutrientes e reduzir custos de produção. Nesse sentido esta pesquisa objetivou avaliar o LETE como complemento da CCA no fornecimento de nutrientes para o milho e consequentemente no desenvolvimento das plantas. O experimento foi realizado em casa de vegetação de setembro a novembro. Adotou-se o delineamento em blocos ao acaso em esquema fatorial 6 x 6, tendo no primeiro fator as doses de CCA: 0; 4; 8; 16; 32; 64 g kg-1e no segundo as doses de LETE: 0; 2; 4; 8; 16; 32 g kg-1, com três repetições. As unidades experimentais foram constituídas de vasos plásticos com 12 dm³ de terra de um Argissolo Vermelho – Amarelo Eutrófico coletado no Centro Agropecuário da Palma-UFPEL, Capão do Leão, RS. Ao final do experimento, com setenta e sete dias, toda a parte aérea do milho foi colhida para quantificar a produção de massa seca e analisar macro (N, P, K, Ca e Mg) e micronutrientes (Fe, Mn, Cu e Zn). Os atributos químicos analisados no solo foram: pH em água, teores de cátions trocáveis (Ca, Mg, K e Na), teores de C, N, P, Si, Fe, Mn, Zn e Cu, bem como, a capacidade de troca de cátions (CTC) a pH 7. Os resultados indicaram que a CCA atuou na correção da acidez do solo, além de contribuir para o crescimento das plantas, se mostrando eficiente como fonte de fósforo e potássio. O uso do LETE contribui no suprimento de nitrogênio e fósforo, proporcionando o aumento da produção de matéria seca das plantas. Com o LETE houve aumento do Zn e Cu, enquanto que a CCA diminuiu a disponibilidade dos mesmos. Embora o LETE possa de fato suprir o N, carente na CCA, ela supre também o P, de modo que, pelo menos em solo bem suprido de K, não há vantagem em misturar CCA ao LETE para suprir estes macronutrientes, ou seja, aquilo que se busca completar na CCA usando o LETE pode ser atendido, mas ao usar o LETE a CCA pode ser dispensada. / The use of waste as fertilizer such as rice husk ash and sewage sludge treatment plant can contribute to the nutrient supply and reduce production costs. In this sense, this research aimed to evaluate the sewage sludge as the rice husk ash complement the supply of nutrients to corn and consequently in plant development. The experiment was carried out in September - November greenhouse. The design was adopted in randomized blocks in a factorial 6 x 6, with the first factor doses of rice husk ash: 0, 4, 8, 16, 32 and 64 g kg-1 and second doses of sewage sludge: 0; 2; 4; 8; 16; 32 g/kg, with three replications. The experimental units consisted of plastic pots with 12dm³ land Red-Yellow Pozolic soil (Ultisol). At the end of the experiment, seventy-seven days all aerial parts of the corn was harvested to quantify the dry matter yield and analyze macro (N, P, K, Ca and Mg) and micronutrients (Fe, Mn, Cu and Zn). Chemical characteristics analyzed in the soil were pH in water exchangeable cations (Ca, Mg, K and Na) contents of C, N, P, Si, Fe, Mn, Zn and Cu, as well as the ability to cation exchange (CTC) at pH 7. The results indicated that the rice husk ash acted to correct soil acidity and contributes to plant growth, proving efficient and phosphorus and potassium source. The use of sewage sludge contributes to the supply of nitrogen and phosphorus, providing increased production of dry matter of the plants. With sewage, sludge was increased Zn and Cu, while rice husk ash decreased availability. Although milk may in fact supply the N, lacking the CCA, it also supplies the P, so that at least well supplied ground K, there is no advantage to mix CCA to LETE to meet these macronutrients, namely that we are seeking to complete the CCA using LETE can be served, but to use the LETE CCA may be waived.

A matéria orgânica do solo (MOS) é composta de uma mistura complexa e heterogênea de compostos orgânicos, sendo as substâncias húmicas (SH) a fração mais recalcitrante da MOS. As SH têm grande influência sobre as propriedades químicas e biológicas do solo, contribuindo como fonte de energia para microrganismos e também contribuindo com a disponibilidade de nutrientes. Além disso, as SH podem contribuir de forma expressiva para o desenvolvimento e produção das plantas cultivadas. Neste sentido, o objetivo deste trabalho foi avaliar a atividade e diversidade da comunidade bacteriana do solo, a disponibilidade de nutrientes e a produtividade da cultura de trigo após aplicação de doses crescentes de SH. Dois experimentos foram montados e avaliados, sendo um ensaio de incubação com um solo arenoso e outro um experimento de casa de vegetação com plantas de trigo em dois solos tropicais distintos (textura arenosa e argilosa). Houve um estímulo à atividade microbiana em ambos os experimentos, sendo este estímulo transitório, o que provavelmente ocorreu devido a um efeito priming provocado pela adição de SH. No entanto não houve alteração na estrutura da comunidade bacteriana pela adição de SH, o que pode ser devido ao fato de ser um material recalcitrante e já presente no solo. Também houve aumento na disponibilidade de fósforo, potássio, cálcio e nitrogênio, bem como da CTC, tanto em solo arenoso quanto argiloso, expressando o efeito das SH na melhoria das propriedades químicas de solos tropicais. Além disso, um efeito significativo foi visto em parâmetros relacionados à produtividade do trigo. Houve aumento de massa seca de raízes e parte aérea, além de aumento no peso e número de grãos, o que pode se refletir em aumento considerável de produtividade. Esses resultados são importantes por mostrarem que mesmo a fração mais recalcitrante da MOS pode influenciar positivamente aspectos químicos e biológicos do solo, contribuindo com a melhoria do sistema de produção e também com maiores produtividades vegetais. / The soil organic matter (SOM) is composed of a complex and heterogeneous mixture of organic compounds, in which the humic substances (HS) are considered to be the most recalcitrant fraction. HS have great influence on chemical and biological soil properties, contributing as energy source for microorganisms and as nutrient reservoir for plants. Furthermore, HS can contribute significantly to the development and production of crop plants. Therefore, the objective of this study was to evaluate the activity and diversity of the soil bacterial community, nutrient availability and productivity of a wheat crop after application of increasing doses of HS. For this purpose, two experiments were performed and evaluated, one is an incubation essay with a sandy soil and the other a greenhouse experiment with wheat plants using two distinct tropical soils as substrates (sandy and clayey). Microbial activity was stimulated in both experiments, and this transient stimulus may have been due to a priming effect caused by the addition of HS. However, there was no change in the bacterial community structure which may be due to the fact that HS is a recalcitrant material and already present in the soil. Nevertheless, we found an increase in the availability of phosphorus, potassium, calcium and nitrogen, as well as in the CEC in both, sandy and clayey soils, showing that HS do improve chemical properties of tropical soils. Furthermore, we found a significant effect on wheat productivity related parameters. There was an increase of dry weight of roots and shoots, as well as increased weight and number of grains, which may be reflected in a significant increase in productivity. These results are important because they show that even the most recalcitrant SOM fraction can positively influence soil chemical and biological aspects, contributing to the improvement of the production system and also to higher plant productivity.

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Northern hardwood forests are expected to experience an increase in mean annual air temperatures, and a decrease in winter snowpack and greater frequency of soil freeze/thaw cycles (FTCs) by the end of the century. As a result of these anticipated changes, northern hardwood forests in the northeastern U.S. will also have warmer soil temperatures in the growing season and colder soils in winter. Prior studies show that warmer soils in the growing season increase net primary productivity (NPP) and C storage as a result of increased soil net N mineralization, while increases in soil freezing in winter reduces plant uptake of N and C as a result of root damage. However, the combined effects of warmer soils in the growing season and increased soil freeze/thaw cycles in winter on tree litter mass and chemistry are unknown. We report here results from the Climate Change Across Seasons Experiment (CCASE) at Hubbard Brook Experimental Forest in New Hampshire, USA to characterize the response of leaf litter mass and chemistry to growing season warming combined with soil freeze–thaw cycles in winter. Across the years 2014-2017, litterfall mass and chemistry (%C, %N, C:N) were not significantly affected by changes in soil temperature; however, there was a trend of higher total litterfall mass and litter N mass from plots where soils were warmed in the growing season, but this increase disappeared with the addition of FTCs in winter. These results indicate that while rates of NPP and the total mass of N could be increased with rising soil temperatures over the next century in northern hardwood forests, the combination of warmer soils in the growing season and colder soils in winter may ultimate have little to no impact on litter mass or chemistry. We conclude that considering the combined effects of climate changes in the growing season and in winter is vital for the accurate determination of the response of litterfall mass and chemistry in northern hardwood forests.

Soil nutrient availability is a key component to understanding the boreal ecosystems, as it directly relates to plant productivity and ecosystem diversity. There is however little known about how the nutrient availability changes seasonally in the boreal forest. This study aimed to understand how soil temperature and nutrient availability changed seasonally as well as with or without reindeer grazing. This was done through measuring NH4, NO3, PO4, total N, and C:N ratio in soil samples taken in- and outside a reindeer exclosure in northern Sweden and then analyzing for differences over sampling time, grazing treatment, and the interaction of both. Differences in soil temperature were more extreme in the grazed areas, giving higher summer temperatures and lower winter temperatures, due to a decreased layer of insulating lichens. Increased soil temperatures also resulted in lowering the C:N ratio, possibly by enhancing the microbial activity leading to larger amounts of CO2 being released. No nutrients differed by grazing treatments, possibly due to the system being complex enough to contain contradicting effects. No systematical differences in seasonal nutrient levels could be found, which was deemed as surprising, but opens for the possibility of sampling one time being sufficient to have an approximation of nutrient levels all year round

Oaks (Quercus spp.) are a dominant genus in forests across the United States that have been declining due to fire suppression and forest mesophication. The reduction of these species may alter forest hydrologic and biogeochemical cycling. Canopy-derived nutrients and interspecific temporal distribution of leaves were quantified under oak and hickory (Carya spp.) species in Mississippi during 2014-2016. Throughfall quantity and chemistry were measured during every storm event under oak and hickory species. Interspecific leaf litter was collected weekly to quantify the timing of leaf fall and leaf litter nutrient content. Throughfall volume and solute fluxes were impacted by seasonality. Mg2+ and DOC were greater in throughfall than precipitation. Leaf loss was slower in oak species during leaf fall. Slower decay in oak litter may correlate with higher C/N ratios compared to hickory species. Results of this study indicate oak species are an important contributor to forest hydrology and nutrient cycling.

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