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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Linking Hydroperiod with Water Use and Nutrient Accumulation in Wetland Tree Islands

Wang, Xin 06 May 2011 (has links)
Many large terrestrial ecosystems have patterned landscapes as a result of a positive feedback system between vegetation communities and environmental factors. One example is tree island habitats in the Florida Everglades. Although they only occupy a small portion of the Everglades landscape, tree islands are important features as the focus of nutrient accumulation and wildlife biodiversity in the Everglades ecosystem. The hardwood hammock community on the elevated head of tree island habitats can accumulate high phosphorus concentration in the otherwise P-limited Everglades ecosystem. In this dissertation, I examined two hypotheses derived from the chemohydrodynamic nutrient accumulation model, which suggests that high transpiration of tree island hammock plants is the driving force for nutrient accumulation in tree island soil. According to this model, I hypothesized that tree islands with lower dry season transpiration should have less phosphorus accumulated than the tree islands with higher dry season transpiration. By examining the water use and nutrient status from 18 tree islands in both slough (perennially wet) and prairie (seasonally wet) locations, I was able to compare water availability and nutrient accumulation in slough and prairie tree islands with different marsh hydroperiods. Chapter 1 uses elemental and stable isotope analysis to look at water stress and nutrient concentration in tree island plants. I showed that the prairie tree island plants suffer from drought stress during the dry season, when the marshes in the prairies dry out. Prairie tree islands also have lower soil and plant P concentration than the slough tree islands. Moreover, I showed that foliar N isotope ratio serves as a stable proxy for community level P availability for tree island plants, and prairie tree island plants have less P available than slough tree island plants. In Chapter 2, I showed that the satellite imagery derived normalized difference water index (NDWI) provides a robust indicator of community level canopy water content of these tree islands. NDWI, used as a proxy for water status, was positively related to foliar N isotope ratio, which suggests that water availability is linked to nutrient availability in the tree island hardwood hammock plant communities. These findings are consistent to the chemohydrodynamic nutrient accumulation model. In Chapter 3, I used sap flow sensors on individual trees to provide a real-time measurement of plant transpiration. I showed that tree island plant transpiration is affected by multiple factors including weather fluctuations, marsh water depth regulated by local water management, and canopy structure of different tree islands. Overall, my dissertation establishes a link between tree island plant water use and nutrient accumulation. It could be potentially important for future restoration plan of tree islands and Everglades hydrological management.
2

Calcium and Potassium Accumulation in Lettuce under Different Nitrogen Regimes

Weil, Sara 23 November 2015 (has links) (PDF)
Nutrient accumulation in vegetable crops is declining. New varieties, selected for high yield, may be subject to a dilution effect of nutrient concentration. Alternatively, soil fertility may be to blame. Here, we investigate how nitrogen fertilization can enhance or suppress calcium and potassium content in two lettuce varieties already known to accumulate high or low amounts of these nutrients. Effects of varying the ammonium:nitrate ratio and effects of calcium carbonate buffering on plant growth by mass and on uptake and accumulation of potassium and calcium in two lettuce (Lactuca sativa L.) cultivars, Two Star and Red Deer Tongue, were investigated in three greenhouse hydroponic experiments in which ammonium supplied none, 6%, 12%, 25%, 50%, 75% or all of the nitrogen. Ammonium, supplied as the sole nitrogen source (15 mM), was toxic under buffered or unbuffered conditions. It limited growth and concentrations of potassium and calcium in lettuce leaves. Proportions of ammonium-N greater than 50% of total N nutrition severely curtailed growth and nutrient accumulation for both cultivars. For both cultivars, optima for all three variables occurred in treatments that contained less than 50% NH4+-N in the total N supply. Application of calcium carbonate buffer did not result in improved maxima for growth and shoot potassium or shoot calcium concentrations compared to the best responses in unbuffered solutions. However, supplying calcium carbonate buffer did raise the minima for growth and shoot potassium and shoot calcium concentration. Both cultivars in buffered solutions compared to unbuffered solutions had significantly greater values for growth and for shoot potassium or shoot calcium concentration in treatments that contained 50% ammonium-N or greater in the total N supply. Although buffering relieved symptoms of ammonium toxicity, it did not eliminate symptoms, confirming the work of other researchers that ammonium toxicity is not due solely to acidification of the root-zone and that buffering has an effect on the capacity of plants to tolerate ammonium nutrition. Supplying nitrogen with ammonium:nitrate ratios in which nitrate predominates enhances yield and accumulation of calcium and potassium in lettuce. Two Star, the modern variety, is more ammonium-sensitive than Red Deer Tongue, the heirloom variety, if calcium carbonate buffering is not provided.
3

Investigating the tomato tolerance to cadmium (Cd) via high throughput proteomics / Investigando a tolerância de tomate ao (Cd) via proteômica de alto rendimento

Nogueira, Marina de Lima 30 April 2019 (has links)
The problem of cadmium (Cd) toxicity aggravates every year. However, the amount of plant species presenting some degree of tolerance to this metal is low. Therefore, it is of utmost importance to understand the Cd tolerance mechanisms. Two tomato cultivars exhibiting distinct levels of tolerance to Cd were investigated by exposing them to 35 μm de CdCl2 for eight days. The samples (roots, stems, and leaves) were collected at 0, 2, 4, 6 and 8 days. The root length and surface area were obtained using a WinRhizo PRO 2009c image analyzer. The ICP OES method was used for the quantification of metals in the different tissues. The translocation index (TrI), metal uptake and Cd distribution nutrient absorbed (NA), and nutrient efficiency (NUE) were calculated. The plant material used for stress indicators and proteomics analysis were collected in liquid nitrogen. Lipid peroxidation and H2O2 contents were obtained by spectrometry. For the proteomics data the gel-free method was used. The stress indicators showed the variation in both cultivars, evidencing the stress caused by the Cd. Chlorosis and necrotic spots were observed in plants exposed to Cd less significant way in the first days of exposure and more evident in the less tolerant cultivar (TTO) in the last days. The growth reduction can be observed in both cultivars, more evident in TTO. Regarding the Cd distribution, the two cultivars showed similar behavior, with the highest percentage of Cd in the roots. The Cd absorption could interfere with both cultivars in the accumulation absorption and efficiency in the use of most nutrients assessed. In general, the Cd interference was more evident at TTO than at YOSH. Highest percentages of TrI were also observed in TTO cultivar. Identification and evaluation of the differentially accumulated protein (DAP) in the two cultivars roots it is possible to observe that in the presence of Cd the cultivar TTO generates a more significant alteration in the amplitude of the accumulation and the number of proteins. These results suggest that the cultivar, which presents a higher degree of tolerance, has some form to make the Cd unavailable or a mechanism that makes the Cd transportation to the leaves more difficult. / O problema da toxicidade do cádmio (Cd) agrava-se a cada ano. No entanto, a quantidade de espécies de plantas que apresentam algum grau de tolerância a este metal é baixa. Portanto, é de suma importância entender os mecanismos de tolerância do Cd. Com esse intuito duas cultivares de tomate (TTO e YOSH) exibindo níveis distintos de tolerância ao Cd foram investigadas, expondo-as a 35 μm de CdCl2 por oito dias. As amostras (raízes, caules e folhas) foram coletadas aos 0, 2, 4, 6 e 8 dias. O comprimento da raiz e área de superfície foram obtidos usando um analisador de imagem WinRhizo PRO 2009c. O método ICP OES foi utilizado para a quantificação de metais nos diferentes tecidos. O índice de translocação (Trl), a absorção de metal e a distribuição de Cd dos nutrientes absorvidos (NA) e eficiência de nutrientes (NUE) foram calculados. O material vegetal usado para indicadores de estresse e análise proteômica foi coletado em nitrogênio líquido. A peroxidação lipídica e o teor de H2O2 foram obtidos por espectrometria. Para os dados proteômicos, foi utilizado o método livre de gel. Os indicadores de estresse mostraram a variação nas duas cultivares, evidenciando o estresse causado pelo Cd. A clorose e manchas necróticas foram observadas em plantas expostas ao Cd de maneira menos significativa nos primeiros dias de exposição e mais evidentes no cultivar menos tolerante (TTO) nos últimos dias. A redução do crescimento pode ser observada em ambas as cultivares, mais evidente no TTO. Quanto à distribuição de Cd, as duas cultivares apresentaram comportamento semelhante, com o maior percentual de Cd nas raízes. A absorção de Cd pode interferir nas duas cultivares na absorção, acúmulo e eficiência no uso da maioria dos nutrientes avaliados. Em geral, a interferência do Cd foi mais evidente no TTO do que no YOSH. As maiores porcentagens de TrI também foram observadas na cultivar TTO. Identificação e avaliação da proteína diferencialmente acumulada (DAP) nas raízes das duas cultivares é possível observar que na presença de Cd a cultivar TTO gera uma alteração mais significativa na amplitude do acúmulo e no número de proteínas. Estes resultados sugerem que a cultivar, que apresenta um maior grau de tolerância, tem alguma forma de tornar o Cd indisponível ou um mecanismo que dificulte o transporte de Cd para as folhas.
4

Ciclagem de nutrientes em sistemas de rotação de culturas

Olibone, Ana Paula Encide [UNESP] 05 December 2008 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:30:25Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-12-05Bitstream added on 2014-06-13T21:01:04Z : No. of bitstreams: 1 olibone_ape_dr_botfca.pdf: 3141451 bytes, checksum: 841b3864f5b41bea3ef33884436e0802 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / As espécies utilizadas em sistemas de rotação de culturas comportamse de maneira diferente quanto à absorção e ciclagem de nutrientes. Além disso, a absorção de nutrientes é influenciada pelas propriedades físicas do solo, capazes de modificar o crescimento e desenvolvimento radicular. O presente trabalho teve como objetivo estudar a ciclagem de nutrientes em três sistemas de rotação de culturas, relacionando-a à atividade radicular da braquiária e sorgo, em sistema de semeadura direta, escarificado (SDCE) e sem escarificação (SDSE), em Nitossolo Vermelho de textura argilosa na cidade de Botucatu-SP. Além das plantas de cobertura também se avaliou a atividade radicular das culturas do milho e da soja. O sistema de rotação foi implantado na safra de 2005/2006 como segue: (1) milheto / soja / sorgo / milho / sorgo/ soja; (2) milheto / soja / braquiária / milho / braquiária / soja e (3) milheto / soja / mamona + braquiária / milho / mamona + braquiária / soja. O delineamento experimental foi o de blocos ao acaso com quatro repetições em parcelas subdivididas. A condução do experimento deu-se por dois anos agrícolas (2006/2007; 2007/2008) para possível observação de algum efeito acumulativo dos tratamentos. A atividade radicular das plantas de cobertura (novembro 2006), do milho (fevereiro 2007) e da soja (dezembro 2007) foi avaliada indiretamente, usando-se rubídio como marcador. Aplicou-se 3 mL da solução de nitrato de rubídio no solo com cateter, a 0,05; 0,10; 0,20, 0,40 e 0,60 m de profundidade e a 0,11 e 0,22 m de distância da planta de referência. Decorrido 4 dias da aplicação, coletou-se as respectivas partes aéreas das plantas, as quais foram secas, moídas e digeridas por via úmida para determinação do teor de rubídio em absorção atômica. Também foram analisadas... / The species used in crop rotation systems differ in nutrient absorption and cycling. Moreover, nutrient absorption is influenced by soil physical properties, which may affect root growth and its development. The present research had as objective to investigate nutrient cycling in three crop rotation systems and its relation to root activity of Brachiaria and sorghum in no tillage system, with and without chiselling. The experiment was carried out in Botucatu, SP, Brazil, in a Red Nitosol, with clay texture. The rotation system was implemented in 2005/2006 and carried out for two growing seasons (November of 2006 and 2007). Crop rotation systems were: (1) Pearl millet / soybean / sorghum / maize / sorghum / soybean; (2) Pearl millet / soybean / Brachiaria / maize / Brachiaria / soybean and (3) Pearl millet / soybean / Brachiaria + castor bean / maize / Brachiaria + castor bean / soybean. The experimental design was the completely randomized block with split-plots and four replications. Root activity was evaluated for either cover crops or maize and soybean. Root activity of cover crops (November of 2006 and 2007), maize (February of 2007) and soybean (December of 2007) was indirectly evaluated, using Rubidium as marker. The solution of 3 mL of rubidium nitrate was applied in soil with a catheter, at 0.05, 0.10, 0.20, 0.40 and 0.60 m depths and at 0.11 and 0.22 m away from the plant in question. The respective shoots were collected, dried, grounded and submitted to humid digestion 4 days after the application to evaluate rubidium level through atomic absorption. Chemical characteristics and soil penetration resistance were also evaluated at 0.00-0.05, 0.05-0.10, 0.10-0.20, 0.20-0.40 and 0.40-0.60 m depths in the respective growing seasons. According to Rb levels observed in dry matter, the highest... (Complete abstract click electronic access below)
5

Marcha de absorção de macronutrientes e de micronutrientes em mudas de goiabeira Paluma e Século XXI /

Franco, Claudenir Facincani. January 2006 (has links)
Resumo: O objetivo do presente estudo foi determinar a curva de crescimento e a marcha de absorção de nutrientes em mudas de duas cultivares de goiabeira obtidas por estaca herbácea. O delineamento experimental utilizado foi em parcelas subdivididas com três repetições. Assim, foram utilizadas como tratamentos principais duas cultivares de goiabeira (Paluma e Século XXI) e, como subtratamentos, sete coletas de plantas, ao longo do período experimental (120 dias) em solução nutritiva. As plantas foram avaliadas quinzenalmente quanto a: altura, número de folhas, diâmetro do caule, área foliar, massa seca (folhas, caule e raízes). Nos diferentes órgãos das mudas, determinou-se o acúmulo de nutrientes. O acúmulo de massa seca das mudas em função do tempo ajustou-se a um modelo quadrático, enquanto que altura, diâmetro de caule, número de folhas e área foliar ajustaram–se a um modelo linear. A muda de goiabeira da cultivar Século XXI tem maior exigência de nutrientes que a da cultivar Paluma, e o período de maior exigência é a partir dos 75 e 45 dias, para Paluma e Século XXI, respectivamente. O acúmulo médio de macronutrientes pelas mudas de goiabeira das cultivares Paluma e Século XXI foi de: K (726 e 696), N (552 e 585), Ca (293 e 302), S (73 e 66), P (64 e 66) e Mg (39 e 41) mg por planta, respectivamente. O acúmulo médio de micronutrientes pelas mudas de goiabeira obedeceu à seguinte seqüência: Fe>Mn>Zn>B>Cu, sendo maior nas folhas para B, Cu, Mn e Zn, e nas raízes para Fe. O acúmulo de micronutrientes para as cultivares Paluma e Século XXI em g por planta foi de: B (632 e 783), Cu (134 e 158), Fe (8103 e 5534), Mn (3052 e 3709) e Zn (760 e 997), respectivamente. / Abstract: This study was carried out to evaluate the vegetative growth and nutrient uptake in guava trees obtained by herbaceous cutting from two cultivars. The experimental design was arranged in split-plots with three replications. The two guava cultivars (Paluma and Século XXI) were used as plots, and the seven samplings performed during a 120-day period in nutritive solution corresponded to split-plots. Plant height, number of leaves, stem diameter, leaf area and dry mass (leaves, stem and roots) were determined every 15 days. The accumulation of macro and micronutrients was measured in the different plant organs. The dry mass accumulation of guava trees in function of time adjusted a quadratic model, while, height, stem diameter, number of leaves and leaf area adjust a linear model. Guava trees from the cultivar ‘Século XXI’ have shown higher macro and micronutrient needs in comparison to ‘Paluma’, and the period of highest demand is after 75 and 45 days for Paluma and Século XXI, respectively. The medium accumulation of macronutrients in guava trees from the cultivars ‘Paluma’ and ‘Século XXI’, in mg per plant, was (respectively): K: 726 and 696; N: 552 and 585; Ca: 293 and 302; S: 73 and 66; P: 64 and 66; and Mg: 39 and 41. The mean accumulation of micronutrients followed the order: Fe>Mn>Zn>B>Cu. This accumulation was higher in leaves for B, Cu, Mn and Zn, and higher in roots for Fe. Nutrient accumulation for the cultivars ‘Paluma’ and ‘Século XXI’, in g per plant, was (respectively): B: 632 and 783; Cu: 134 and 158; Fe: 8103 and 5534; Mn: 3052 and 3709; and Zn 760 and 997. / Orientador: Renato de Mello Prado / Coorientador: William Natale / Banca: Francisco Maximino Fernandes / Banca: José Carlos Barbosa / Mestre
6

Marcha de absorção de macronutrientes e de micronutrientes em mudas de goiabeira Paluma e Século XXI

Franco, Claudenir Facincani [UNESP] 06 December 2006 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:23:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-12-06Bitstream added on 2014-06-13T19:50:04Z : No. of bitstreams: 1 franco_cf_me_jabo.pdf: 963648 bytes, checksum: db941edb704e94c321d40bdc23a75663 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O objetivo do presente estudo foi determinar a curva de crescimento e a marcha de absorção de nutrientes em mudas de duas cultivares de goiabeira obtidas por estaca herbácea. O delineamento experimental utilizado foi em parcelas subdivididas com três repetições. Assim, foram utilizadas como tratamentos principais duas cultivares de goiabeira (Paluma e Século XXI) e, como subtratamentos, sete coletas de plantas, ao longo do período experimental (120 dias) em solução nutritiva. As plantas foram avaliadas quinzenalmente quanto a: altura, número de folhas, diâmetro do caule, área foliar, massa seca (folhas, caule e raízes). Nos diferentes órgãos das mudas, determinou-se o acúmulo de nutrientes. O acúmulo de massa seca das mudas em função do tempo ajustou-se a um modelo quadrático, enquanto que altura, diâmetro de caule, número de folhas e área foliar ajustaram se a um modelo linear. A muda de goiabeira da cultivar Século XXI tem maior exigência de nutrientes que a da cultivar Paluma, e o período de maior exigência é a partir dos 75 e 45 dias, para Paluma e Século XXI, respectivamente. O acúmulo médio de macronutrientes pelas mudas de goiabeira das cultivares Paluma e Século XXI foi de: K (726 e 696), N (552 e 585), Ca (293 e 302), S (73 e 66), P (64 e 66) e Mg (39 e 41) mg por planta, respectivamente. O acúmulo médio de micronutrientes pelas mudas de goiabeira obedeceu à seguinte seqüência: Fe>Mn>Zn>B>Cu, sendo maior nas folhas para B, Cu, Mn e Zn, e nas raízes para Fe. O acúmulo de micronutrientes para as cultivares Paluma e Século XXI em g por planta foi de: B (632 e 783), Cu (134 e 158), Fe (8103 e 5534), Mn (3052 e 3709) e Zn (760 e 997), respectivamente. / This study was carried out to evaluate the vegetative growth and nutrient uptake in guava trees obtained by herbaceous cutting from two cultivars. The experimental design was arranged in split-plots with three replications. The two guava cultivars (Paluma and Século XXI) were used as plots, and the seven samplings performed during a 120-day period in nutritive solution corresponded to split-plots. Plant height, number of leaves, stem diameter, leaf area and dry mass (leaves, stem and roots) were determined every 15 days. The accumulation of macro and micronutrients was measured in the different plant organs. The dry mass accumulation of guava trees in function of time adjusted a quadratic model, while, height, stem diameter, number of leaves and leaf area adjust a linear model. Guava trees from the cultivar Século XXI have shown higher macro and micronutrient needs in comparison to Paluma , and the period of highest demand is after 75 and 45 days for Paluma and Século XXI, respectively. The medium accumulation of macronutrients in guava trees from the cultivars Paluma and Século XXI , in mg per plant, was (respectively): K: 726 and 696; N: 552 and 585; Ca: 293 and 302; S: 73 and 66; P: 64 and 66; and Mg: 39 and 41. The mean accumulation of micronutrients followed the order: Fe>Mn>Zn>B>Cu. This accumulation was higher in leaves for B, Cu, Mn and Zn, and higher in roots for Fe. Nutrient accumulation for the cultivars Paluma and Século XXI , in g per plant, was (respectively): B: 632 and 783; Cu: 134 and 158; Fe: 8103 and 5534; Mn: 3052 and 3709; and Zn 760 and 997.
7

Long-Term Nutrient Removal and Nutrient Mass Balance of a Free Water Surface Constructed Wetland Polishing Municipal Lagoon Effluent

Patel, Meetkumar 11 January 2023 (has links)
A large pilot-scale free water surface (FWS) constructed wetland polishing effluent from an annual (spring) discharge municipal lagoon was operated for ten years followed by eleven years of dormancy and then restarted with an increase in operating depth. No significant effect of system aging was observed on Biological Oxygen Demand (BOD), total phosphorus (TP), and soluble reactive phosphorus (SRP) removal efficiencies, although internal TP water column concentrations in the first wetland and pond cells increased with time due to resuspension of accumulated sediments. Nitrate and ammonium removal efficiencies were higher during the start-up period due to plant establishment, while organic nitrogen and nitrate removal efficiencies increased during the restart period, likely due to a combination of the increased operating depth and accumulated sediments. No seasonal temperature effect was observed for nitrate or BOD removal efficiency, however, TP removal efficiencies increased with increasing influent concentrations due to seasonal algae growth. TSS removal efficiency increased significantly during the restart period, most likely due to an increase in the operating depth. Phosphorus was found to be mostly stored in the soil, followed by sediment and plants, while nitrogen was found to be stored more in plants, followed by soil and sediment. The wetland system was shown to be effective at the long-term removal of organic matter (BOD5 < 10 mg/L) and TP (87% average removal efficiency), while TSS removal efficiency increased to 97% with an increase in operating depth from 25 to 50 cm.
8

Ureia estabilizada na adubação nitrogenada de cana-de-açúcar / Stabilized urea in nitrogen fertilization of sugarcane

Moreira, Lílian Angélica 08 February 2017 (has links)
A adubação nitrogenada de soqueira de cana-de-açúcar no Brasil normalmente é feita no período seco do ano e a principal fonte de N é o nitrato de amônio, apesar de a ureia ser o principal fertilizante nitrogenado consumido no Brasil e no mundo. Para viabilizar o uso de ureia em áreas de cana-de-açúcar colhida sem queima, com grande quantidade de palha recobrindo o solo, devem ser adotadas estratégias que reduzam as perdas de amônia por volatilização, como uso de ureia estabilizada com inibidores de urease. Trabalhos prévios indicaram a necessidade de aumentar a concentração do inibidor de urease NBPT na ureia para reduzir perdas de amônia por volatilização em áreas de cana-crua, porém os efeitos na produtividade da cultura ainda não foram estudados. A hipótese deste trabalho é de que o aumento da concentração do inibidor de urease NBPT na ureia irá proporcionar ganhos de produtividade comparado à ureia convencional, demonstrando a viabilidade do uso de ureia estabilizada para adubação de soqueira de cana-crua. O presente trabalho foi executado em dois locais (Experimento 1, Latossolo Vermelho-Amarelo distrófico de textura muito argilosa e Experimento 2, Latossolo Vermelho-Amarelo eutrófico de textura média) para avaliar o comportamento produtivo de soqueiras de cana-de-açúcar em função de doses de N nas formas de nitrato de amônio, ureia e ureia estabilizada com diferentes concentrações de NBPT. O delineamento experiemental foi de blocos inteiramente casualizados no esquema fatorial 6 x 2 + 1, sendo seis fontes de N (nitrato de amônio, ureia e ureia estabilizada com quatro doses de NBPT variando de 530 a 2000 mg kg-1), duas doses de N (50 e 100 kg ha-1 de N) e um tratamento adicional (Controle, sem adubação nitrogenada). Foram avaliados o perfilhamento, teor foliar de N, índice SPAD, produtividade de colmos, acúmulo de N na parte aérea e os atributos tecnológicos. Também foi avaliada a atividade enzimática da glutamina sintetase (GS) e nitrato redutase (NR) no Experimento 2. Os dados foram submetidos a análise de variância ao nível de 10 % de significância pelo teste F, e os fatores significativos foram comparados pelo teste Tukey a 10 % de significância. Os teores foliares de N não foram alterados pela interação dos fatores, sendo mais importante o aumento da dose de N, o que também ocorreu para atividade das enzimas GS e NR e para o índice SPAD. A produtividade de colmos foi influenciada distintamente entre as áreas. No Experimento 1, houve resposta significativa para as doses de N, independente da fonte de N . No Experimento 2 não houve diferença significativa na produtividade de colmos entre as doses e fontes de N. Os resultados deste trabalho indicam que não é necessário aumentar a concentração de NBPT na ureia e que, tanto a ureia convencional quanto a ureia estabilizada podem ser utilizadas para adubação nitrogenada de soqueira de cana-de- açúcar como fontes opcionais ao nitrato de amônio. / Nitrogen fertilization of sugarcane ratoon in Brazil is usually performed in the dry period of the year and the main source of N is ammonium nitrate, although urea is the main nitrogen fertilizer consumed in Brazil and in the world. In order to allow urea usage in green cane trash blanketing (GCTB) systems, with high amount of straw left on soil surface, strategies that reduce ammonia losses are required, such as the use of urea stabilized with urease inhibitors. Previous research indicated the need to increase the concentration of the urease inhibitor NBPT in urea to reduce ammonia losses in GCTB systems, but the effects on such increase on yield performance is unclear. This study was undertaken to test the hypothesis that increasing the concentration of NBPT in urea will provide yield gains when compared to untreated urea, demonstrating the feasibility of using stabilized urea in GCTB areas. Two field trials (Experiment 1, Oxisols of very clayey texture and Experiment 2, medium-texture Oxisols) were set up to evaluate the yield performance of sugarcane fertilized with N rates as ammonium nitrate, urea and urea stabilized with different concentrations of NBPT. The experimental design was a complete randomized blocks on factorial scheme 6 x 2 + 1, with six N sources (ammonium nitrate, urea and urea stabilized with NBPT concentration ranging from 530 to 2000 mg kg-1), two doses of N (50 and 100 kg ha-1 of N) and an additional control (no N fertilization). It was evaluated the tillering, foliar N content, SPAD index, crop yield, shoot N accumulation and the technological attributes. The enzymatic activity of glutamine synthetase (GS) and nitrate reductase (NR) was also evaluated in Experiment 2. Data were submitted to analysis of variance at the 10 % level of significance by the F test, and the significant factors were compared by the Tukey test at 10 % significance. Leaf N contents weren\'t affected by the interaction of the factors, being more important the increase of the dose of N, which also occurred for the activity of GS, NR and for the SPAD index. Sugarcane response to N fertilization varied among sites. In Experiment 1, there was a significant response to N rates, independently of N sources evaluted. In Experiment 2 there was no significant effect of N sources or rates on sugarcane yield. The results of this study indicate that increasing NBPT concentration in urea will not improve sugarcane yield. However, both urea and stabilized urea resulted in similar yield performance when compared to ammonium nitrate for fertilization of GCTB systems.
9

An?lise de crescimento, fenologia e acumula??o de nutrientes de quatro gen?tipos de bananeira no estado do Rio de Janeiro / Analysis of growth, phenology and nutrient accumulation of four banana genotypes in the Rio de Janeiro State

Busquet, Rubens Nei Bria?on 28 March 2006 (has links)
Made available in DSpace on 2016-04-28T14:58:59Z (GMT). No. of bitstreams: 1 2006-Rubens Nei Briacon Busquet.pdf: 998513 bytes, checksum: 2e2a50b0c0141ff91d47dae53e3ba216 (MD5) Previous issue date: 2006-03-28 / This work had the objective of to analyze the development pattern and the nutrient accumulation of four genotypes of banana, with micropropagated plantlets, in the conditions of the State of Rio de Janeiro. An experiment was driven in the Department of Fitotecnia of UFRRJ, in Planossolo, in a randomized blocks design with four treatments and four repetitions of 45 plants for plot, in the spacing of 3x2 m. Four genotypes of the banana were evaluated: Thap Maeo (AAB), FHIA-18 (AAAB), SH3640 (AAAB) and Prata An? (AAB). Only the mother plant was driven per hole, being eliminated the whole sucker. In the first stage, leaves of the four genotypes were sampled eight weeks after transplant (WAT), to determine the correction factor to estimate the leaf area from the length and width of foliar limbo. The angular coefficients of the regression revealed that there are significant differences among genotypes, indicating that in the determination of the leaf area of banana tree by ruler, the factor of correction of 0.79 should be used for cultivar SH 3640, FHIA 18 and Thap Maeo, and 0.83 for Prata An?. The second stage, the temperature and the precipitation arise as the climate factors more related to the rate of leaf emission of the four genotypes.. The genotype Thap Maeo presented larger vegetative cycle (366 days) and total (468 days) and larger plant height (3.0 m) that the other genotypes. The genotypes didn't present differences in the reproductive cycle and in the diameter of plants. The genotype Fhia 18 presented the largest total mass of fruits for plant. The genotype Thap Maeo presented larger medium number of bunches for bunch, the largest of number of fruits for bunch, the largest relationship pulp-peel, however the smallest fruit size. The genotype SH 3640, although presented fruits of greatest weight and size, presented the smallest number of fruits for bunch and the pulp-peel ratio. In the third stage, to quantify the time variation of plant biomass and nutrient accumulation, one plant was sampled per plot on 8 harvests spaced 8 weeks, when the leaf area measured, and the mass and concentrations of N, P, K, Ca, Mg measured in each plant portion. The growth rates and of nutrient accumulation were measured through the functional plant growth analysis. The mass of rhizomes and stems increased up to 48 WAT and stabilized at 56 WAT. The leaf area, and the mass of active leaves and petioles increased up to 40 WAT and stabilizing in the last three harvests. The net assimilation rate increased between 8 and 24 WAT, and declined mainly after 32 SAT. The rates of nutrient accumulation presented the same pattern regarding with the time of maximal accumulation, varying from 30 to 33 WAT. From the total of nutrients accumulated by the banana plant, the bunch exported after fruit harvest 50% of N, 38% of P, 60% of K, 11% of Ca and 14% of Mg. The total amount of nutrient accumulated, in kg per ha, was 54.5 of N, 14.4 of P, 131.5 of K, 62,5 of Ca and 53 of Mg. . / Este trabalho teve como objetivo analisar o padr?o de crescimento e acumula??o de nutrientes e o comportamento fenol?gico de quatro gen?tipos de bananeiras (Musa spp.), com mudas produzidas por micro-propaga??o, nas condi??es do Estado do Rio de Janeiro. Foi conduzido um experimento no Departamento de Fitotecnia da UFRRJ, em Planossolo, em delineamento em blocos ao acaso com quatro tratamentos e quatro repeti??es de 45 plantas por parcela, no espa?amento de 3x2 m. Foram avaliados quatro cultivares de banana: Thap Maeo (AAB), FHIA-18 (AAAB), SH3640 (AAAB) e Prata An? (AAB). Foi conduzida apenas a planta m?e por touceira, eliminando-se a brota??o lateral. Na primeira etapa foi feita a coleta de folhas, com o objetivo de determinar o fator de corre??o para estimar a ?rea foliar a partir do comprimento e largura de limbo foliar. Houve diferen?as significativas entre gen?tipos, indicando que deve-se usar o fator de corre??o de 0,79 para a as cultivares SH3640, FHIA 18 e Thap Maeo, e 0,83 para Prata An?. A segunda etapa teve como objetivo verificar a taxa de lan?amento de folhas de quatro gen?tipos de bananeiras e correlacion?-la com as condi??es clim?ticas e estudar o comportamento fenol?gico dos quatro gen?tipos. A temperatura e a precipita??o apresentaram-se como os fatores de clima mais relacionados ? taxa de emiss?o de folhas pelos quatro gen?tipos. Os gen?tipos apresentaram comportamento diferenciado quanto ? taxa de lan?amento de folhas nos per?odos 8, 32 e 64 SAT, quando o gen?tipo Prata An? apresentou o maior n?mero de folhas lan?adas. O gen?tipo Thap Maeo apresentou maior ciclo vegetativo (366 dias) e total (468 dias) e maior altura de planta que os demais gen?tipos. O gen?tipo Fhia 18 apresentou a maior massa total de frutos por planta. O gen?tipo Thap Maeo apresentou maior n?mero m?dio de pencas e frutos por cacho, a maior rela??o polpa-casca, por?m o menor tamanho de fruto. O gen?tipo Prata An? apresentou o valor mais elevado de s?lidos sol?veis totais. O gen?tipo SH 3640, apresentou o pior desempenho. Na terceira etapa, para quantificar a varia??o temporal de biomassa vegetal e de acumula??o de nutrientes, foram efetuadas 8 coletas espa?adas 8 semanas, quando foi coletada uma planta por parcela, separada em rizoma, limbo foliar, bainha das folhas, pec?olo, enga?o, flores, br?cteas e frutos, e determinando-se a ?rea foliar. No material vegetal obtido em cada coleta foram determinados os teores de N, P, K, Ca, Mg. As taxas de crescimento e de acumula??o de nutrientes foram mensuradas atrav?s do m?todo funcional de an?lise de crescimento vegetal. A massa seca do rizoma e do pseudocaule aumentou significativamente at? 48 SAT, se estabilizando aos 56 SAT. A ?rea foliar, e a massa das folhas ativas e dos pec?olos aumentaram at? 40 SAT, se estabilizando nas tr?s ?ltimas coletas.A ?rea foliar espec?fica reduziu-se ao longo das coletas em todos os gen?tipos, sendo que Fhia 18 apresentou os menores valores e Thap Maeo os maiores valores de ?rea foliar espec?fica. A taxa de assimila??o l?quida aumentou entre 8 SAT e 24 SAT, quando decaiu principalmente a partir de 32 SAT. As taxas de acumula??o absoluta de N, P, K, Ca e Mg apresentaram-se similares quanto a ?poca de m?xima acumula??o, variando de 30 a 33 SAT.. Ap?s a colheita, do total de nutrientes imobilizados pela bananeira, foram exportados para o cacho 50% do N, 38% do P, 60% do K, 11% do Ca e 14% do Mg. O total de nutrientes acumulado, em kg por ha, foi 54,5 de N, 14,4 de P, 131,5 de K, 62,5 de Ca e 53 de Mg.
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Atributos químicos após dezenove aplicações de dejeto líquido de suínos em argissolo sob plantio direto / Chemical attributes after nineteen applications of pig slurry in alfisol under no tillage

Lourenzi, Cledimar Rogério 27 September 2010 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The use of pig slurry as a source of nutrients can affect the conditions of acidity and nutrient availability, altering the environment for crop development. The objective of this study was to evaluate changes in chemical properties of an Alfisol after 95 months of cultivation and 19 applications of pig slurry, conducted under no-tillage system. The experiment was installed in May 2000, an experimental area under no-tillage at the Federal University of Santa Maria, and conducted until January 2008. The experimental design was a randomized block design with three replications. Were performed nineteen surface applications of 0, 20, 40 and 80 m3 ha-1 of pig slurry during the experiment and in the end, were collected samples of soil layers of 0-2, 2-4, 4 -6, 6-8, 8-10, 10-12, 12-14, 14-16, 16-18, 18-20, 20-25, 25-30, 30-35, 35-40, 40-50 and 50-60 cm depth. The soil was collected with the aid of a spade cut-off, air dried, milled manually with the aid of a roller and passed through a sieve with 2 mm mesh and reserved. It was determined the pH values in water (1:1), SMP, the levels of exchangeable Al, Ca, Mg and K. With the data obtained were calculated the sum of bases, base saturation and Al saturation, CEC pH7, CEC effective and potential acidity (H + Al). Were also determined the total contents of N, P and K, levels of mineral N, available P and soil organic matter. The successive application of pig slurry promoted increase in pH values in water up to 8 cm of soil, however, no change in potential acidity. Also caused increased levels of exchangeable Ca and Mg in the surface layers of soil, reflecting an increase in the values of sum of bases, base saturation and decreasing Al saturation. Furthermore, the applications over time caused an increase in levels of soil organic matter, reflecting in increased levels of total N to a depth of 30 cm. Applications of manure resulted in increased levels of available P and exchangeable K to a depth of 60 cm, while for the total P increases were observed up to 30 cm depth. The changes observed in soil chemical properties provides better environment for root development of crops due to lower acidity and higher nutrient availability in soil solution. However, one must be careful in extrapolating these results to different soils, although the phenomena are similar, they occur in different magnitudes depending on soil characteristics. / A utilização de dejeto líquido de suínos como fonte de nutrientes pode afetar as condições de acidez e de disponibilidade de nutrientes, modificando o ambiente para o desenvolvimento das culturas. O objetivo do presente trabalho foi avaliar as alterações nos atributos químicos de um Argissolo após 95 meses de cultivo e 19 aplicações de dejeto líquido de suínos, conduzido sob sistema de plantio direto. O experimento foi instalado em maio de 2000, numa área experimental sob sistema plantio direto na Universidade Federal de Santa Maria, e conduzido até janeiro de 2008. O delineamento experimental foi de blocos ao acaso com três repetições. Foram realizadas dezenove aplicações superficiais de 0, 20, 40 e 80 m3 ha-1 de dejeto líquido de suínos, durante a condução do experimento e, ao final, foram coletadas amostras do solo nas camadas de 0-2, 2-4, 4-6, 6-8, 8-10, 10-12, 12-14, 14-16, 16- 18, 18-20, 20-25, 25-30, 30-35, 35-40, 40-50 e 50-60 cm de profundidade. O solo foi coletado com o auxílio de uma pá-de-corte, seco ao ar, moído manualmente com o auxílio de um rolo destorroador e passado em peneira com malha de 2 mm e reservado. Foram determinados os valores de pH em água (1:1), índice SMP, os teores trocáveis de Al, Ca, Mg e K. Com os dados obtidos foram calculadas a soma de bases, saturação por bases e por Al, CTC pH7,0, CTC efetiva e acidez potencial (H+Al). Também foram determinados os teores totais de N, P e K, os teores de N mineral, P disponível e matéria orgânica do solo. A aplicação sucessiva de dejeto líquido de suínos promoveu incremento nos valores de pH em água do solo até 8 cm, no entanto, não houve alteração nos valores de acidez potencial. Também provocou aumento nos teores trocáveis de Ca e Mg nas camadas superficiais do solo, refletindo em aumento nos valores de soma de bases, saturação por bases e diminuindo a saturação por alumínio. Além disso, as aplicações ao longo do tempo promoveram aumento nos teores de matéria orgânica do solo, até 60 cm de profundidade, refletindo em aumento nos teores de N total até a profundidade de 30 cm. As aplicações de dejeto provocaram incremento nos teores de P disponível e K trocável até a profundidade de 60 cm, enquanto que para o P total os incrementos foram observados até 30 cm de profundidade. As alterações observadas nos atributos químicos do solo proporcionam melhor ambiente para o desenvolvimento radicular das culturas devido à redução da acidez e maior aporte de nutrientes na solução do solo. No entanto, deve-se tomar cuidado ao extrapolar esses resultados para solos com características diferentes, embora os fenômenos se assemelhem, estes ocorrem em magnitudes diferentes dependendo das características do solo.

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