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Made available in DSpace on 2014-06-11T19:26:46Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-07-21Bitstream added on 2014-06-13T20:55:18Z : No. of bitstreams: 1 silvajunior_hm_me_botfca.pdf: 985374 bytes, checksum: cb99ee317e2bbf5318d8961c31b22a76 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Universidade Estadual Paulista (UNESP) / Em irrigação, a uniformidade está relacionada com a capacidade do equipamento em fornecer a mesma quantidade de água em toda a área irrigada. Em sistemas de irrigação localizada, o dimensionamento baseia-se na uniformidade de emissão (UE) pré-estabelecida, que é o resultado conjunto das características do equipamento e de sua configuração hidráulica. Entretanto, este valor desejado de UE pode ou não ser confirmado pelo projeto final, em decorrência da declividade da área e dos diâmetros comerciais da tubulação, que dificilmente coincidem exatamente com aqueles definidos nos cálculos do dimensionamento. Além disso, há uma questão: dimensionar sistemas de irrigação localizada visando obter elevada uniformidade de emissão significa alcançar elevada uniformidade na produção ? Este trabalho teve como objetivo avaliar a relação entre a uniformidade de emissão de projeto e a uniformidade da produção, em sistema de irrigação por microaspersão. A análise de sensibilidade envolveu diferentes declividades, 0%, 3%, 6%, 9% e 12%, e diferentes valores de uniformidade de emissão de projeto, 60% 70%, 75%, 80%, 85%, 90% e 94%. Considerou-se um pomar de citros com dimensões de 400m por 600m, com declividade variável na direção do menor comprimento. As linhas de plantio estavam em nível, na direção da maior dimensão. O espaçamento adotado no pomar era de 7m x 4m. A linha de derivação operava sempre em declive e tinha espaçamento regular entre linhas laterais de 7m, sendo que a primeira estava a 3.5m. Observou-se maiores valores de uniformidade da vazão nos maiores valores de declividade, exceto em 12%. Quando se calculou o coeficiente de variação da produtividade utilizando a função de produção para o fator água, verificou-se uma melhoria da uniformidade em todas... / Irrigation uniformity is related to the ability of equipment to provide the same amount of water throughout the irrigated area. In irrigation systems, the design is based on the pre-established emission uniformity (EU) which is the combined result of the equipment characteristics and its hydraulic configuration. However, this desired value of the EU may not be confirmed by the final project, due to the slope of the area and the commercial diameters of the pipe. This study aimed to evaluate the uniformity of design of an irrigation system and its relationship with yield. The sensitivity analysis involved different slopes, 0, 3, 6, 9 and 12%, and different values of emission uniformity, 60, 70, 75, 80, 85, 90 and 94% . The design of trickle irrigation was applied to a citrus orchard with dimensions of 400m x 600m, with variable slope towards the shorter length. The tree rows were leveled in the larger direction and the spacing adopted in the orchard was 7m x 4m. The manifold line was always operating on a slope and had regular spacing between the lateral lines of 7m, the first of which was 3.5m. Higher discharge values were observed in the highest slope values except at 12%. When we calculated the variation coefficient of productivity using the production function for the water factor, there was an improvement of uniformity in all the combinations evaluated. Comparing the index performance evaluation, it was observed they had the same pattern performance in all combinations studied. The lowest values were obtained for the indicator emission uniformity and the largest for distribution uniformity, and the Barragan index had intermediary performance. The variation pressure coefficients ranged from 0.02 to 0.33, the flow variation coefficient ranged from 0.01 to 0.17, and production variation coefficients with 60 days of irrigation ranged from 0.0003 to 0.0125

The application of N-fertilizers mixed with a surface irrigation stream (surface N-fertigation) is widely practiced in the Yume Mesa. Guidelines for the efficient management of surface N-fertigation systems are needed. The purpose of the work reported herein is to evaluate the relative effectiveness of existing surface N-fertigation management practices in the Yuma Mesa. This has been accomplished through the following steps: (1) a complete set of performance indices that can be used to assess the relative merit of alternative management scenarios are identified and defined and Equations as well as solutions for quantifying the performance indices are proposed; (2) surface fertigation field experiments (using Br- as a tracer) were performed in two irrigation basins at the Yuma Mesa research farm of the University of Arizona during the fall season of 2000; (3) the spatial distribution as well as the application efficiency and adequacy of Br- applied with irrigation water was determined using the performance functions proposed herein; and (4) the results were analyzed to assess the merits and limitations of existing practices.

'Newhall' navel oranges on 'Carrizo' rootstock were planted in Mar. 1997 at the Citrus Agricultural Center. The objectives of this experiment were to i) determine the effects of N rate and fertigation frequency for microsprinkler-irrigated navel oranges on tree N status, and crop yield and quality; and ii) develop Best Management Practices which promote optimum tree growth and production while minimizing nitrate leaching. The trees are equipped with a microsprinkler irrigation system. The experiment is a randomized complete block factorial with N rates of 0, 0.15, 0.30, and 0.45 lb N/tree/year, and fertigation frequencies of weekly, monthly, and three times per year. Unfertilized control trees are also included in the experimental design. Each of the ten treatments is replicated five times. The trees were harvested in Jan. 2002. Fruit were processed through an automatic fruit sizer, and fruit from each plot were further evaluated for fruit quality. Leaf N concentration was responsive to N rate, but not to fertigation frequency. Leaf N in all fertilized plots was above tissue critical levels. Fruit yield in fertilized plots was higher than in unfertilized plots, but, in fertilized treatments, there was no significant effect of N rate or fertigation frequency on fruit yield or quality.

'Newhall' navel oranges on 'Carrizo' rootstock were planted in Mar. 1997 at the Citrus Agricultural Center. The objectives of this experiment were: i) to determine the effects of N rate and fertigation frequency for microsprinkler-irrigated navel oranges on tree N status, and crop yield and quality; and ii) to develop Best Management Practices which promote optimum tree growth and production while minimizing nitrate leaching. The trees are equipped with a microsprinkler irrigation system. The experiment is a randomized complete block factorial with N rates of 0, 0.15, 0.30, and 0.45 lb N/tree/year, and fertigation frequencies of weekly, monthly, and three times per year. Unfertilized control trees are also included in the experimental design. Each of the ten treatments is replicated five times. The trees were harvested for the first time in Feb. 2001. Fruit were processed through an automatic fruit sizer, and fruit from each plot were further evaluated for fruit quality. Although unfertilized control trees had lower leaf N content than fertilized trees, fruit yield and quality of controls was no lower than fertilized trees. Similarly, there were few statistically significant differences in fruit yield and quality between trees receiving different N rates and fertigation frequencies.

Thesis (MScAgric)--University of Stellenbosch, 2002. / ENGLISH ABSTRACT: Daily daylight fertigation regimes (involvinq drip fertigation, on a daily basis, during the daylight hours) are becoming widely used in the South African citrus industry in the endeavor to enhance tree productivity. Such regimes could provide sensitive nutrient and moisture management, reducing plant stress in general as well as the response time to root-directed cultural activities. There is a need to evaluate the efficacy of daily daylight fertigation systems relative to conventional irrigation systems. Standard horticultural evaluation of orchard management practices is very time consuming. We opted for physiological studies comparing plant stress levels, in an attempt to quantify plant performance under each system. Citrus trees under daily daylight fertigation and conventional micro-jet and drip-irrigated regimes were monitored to establish plant stress levels as indicated by sap flow, xylem water potential, stomatal conductance and chlorophyll a fluorescence. Plants under a daily daylight fertigation regime are believed to have good soil water conditions in their rooting volume, and therefore experience negligible baseline levels of stress. The trees do, however, experience midday depression in stomatal conductance, to a lesser degree, but not unlike trees under conventional regimes. It appears as if a larger rooting volume of microjet irrigation regimes enhances recovery from the midday depression. It is recommended that producers optimise productivity during the moming hours, by early irrigation, so that plants can function optimally, whilst environmental conditions are most favourable for high physiological activity. We also assessed the effect of withholding water from trees adapted to a daily daylight fertigation regime to evaluate the risk involved with short-term water deficits in trees adapted to this regime, as well as the usefulness of physiological techniques for identifying water stress. Stomatal conductance and xylem water potential indicated water stress sooner than the other physiological parameters. Citrus trees seem to be relatively insensitive to water deficit stress as measured by sap flow and chlorophyll a fluorescence. Sap flow is buffered by tree capacitance, and although mediated via stomatal conductance, atmospheric conditions and not the soil water content primarily determine it. As daily fertigation is applied to trees under DOF regimes, they exhibit more optimal levels of xylem water potential and stomatal conductance, compared to trees from which water is withheld. Although alleviating it to a degree, daily irrigation did not mitigate the midday depression in these values. Seen over a season, even small enhancements of stomatal conductance (and with it photosynthesis and possibly, growth) and xylem water potential, could incrementally produce higher yields. / AFRIKAANSE OPSOMMING: In die strewe na verhoogde boomproduktiwiteit, word daaglikse sproeibemesting (deur 'n drupbesproeiingsstelsel toegedien tydens die dagligure) al meer algemeen in die Suid Afrikaanse sitrusbedryf gebruik. Hierdie praktyk verminder algemene plantstres deur baie spesifieke voedingsen vogbeheer, en verkort ook die plant se reaksietyd op wortelgerigte bewerkingsaktiwiteite. Dit is nodig om die relatiewe voordeel van daaglikse sproeibemesting teenoor konvensionele besproeiingssisteme te evalueer. Huidige tuinboukundige evaluering van boord-bestuurspraktyke is baie tydrowend. In 'n poging om plantreaksie onder verskillende praktyke te beskryf, het ons besluit om die plantstresvlakke met fisiologiese metodes te vergelyk. Sitrusbome onder daaglikse sproeibemesting, en konvensionele mikro- en drupbesproeiing, is onderskeidelik gemonitor om die plant se stresvlakke vas te stel, soos aangedui deur sapvloei, xileem-waterpotensiaal, stomatale geleiding en chlorofil a f1uoresensie. Die plante onder daaglikse sproeibemesting ondervind lae viakkke van waterstremming, waarskynlik weens hoë grondvogtigheid in die wortelsone. Die bome ondervind wel, soos dié onder konvensionele besproeiing, middagdepressie in stomatale geleiding, hoewel tot 'n mindere mate. Dit blyk asof die groter wortelvolume van mikrospuit besproeide bome die herstel na middagdepressie bespoedig. Produsente word aangeraai om die oggendure optimaal te gebruik deur vroeg te besproei sodat plantproduktiwiteit hoog is terwyl die omgewingsfaktore op hul gunstigste is en wanneer die hoogste fisiologiese aktiwiteit voorkom. Ons het ook die effek van wateronthouding gemeet op die bome wat aangepas is vir daaglikse sproeibemesting. Sodoende is die risiko verbonde aan 'n korttermyn watertekort op hierdie bome ge-evalueer, asook die bruikbaarheid van fisiologiese tegnieke om waterstremming in sitrus te identifiseer. Stomatale geleiding en xileem-waterpotensiaal het waterstremming vroëer aangedui as die ander fisiologiese parameters. Sitrusbome blyk redelik onsensitief te wees teenoor droogtestremming soos gemeet deur sapvloei en chlorofil a fluoresensie. Sapvloei word gebuffer deur boom-kapasitansie, en alhoewel sapvloei gereguleer word deur stomatale geleiding, is dit die atmosferiese toestande (hoofsaaklik dampdruk verskil) wat dit primêr beïnvloed, en nie die grond-water inhoud nie. Omdat bome daagliks sproeibemes word, het hulle meer optimale vlakke van xileemwaterpotensiaal en stomatale geleiding in vergelyking met bome waarvan water weerhou is. Alhoewel daaglikse sproeibemesting die middagdepressie verlaag het, is dit nie daardeur opgelos nie. Oor die typerk van 'n seisoen kan selfs minimale verhogings in stomatale geleiding (en daarmeesaam fotosintese en moontlik groei) en xileem-waterpotensiaal, hoër opbrengste tot gevolg hê.

Orientador: João Carlos Cury Saad / Banca: João Luis Zocoler / Banca: Altair Bertonha / Resumo: Em irrigação, a uniformidade está relacionada com a capacidade do equipamento em fornecer a mesma quantidade de água em toda a área irrigada. Em sistemas de irrigação localizada, o dimensionamento baseia-se na uniformidade de emissão (UE) pré-estabelecida, que é o resultado conjunto das características do equipamento e de sua configuração hidráulica. Entretanto, este valor desejado de UE pode ou não ser confirmado pelo projeto final, em decorrência da declividade da área e dos diâmetros comerciais da tubulação, que dificilmente coincidem exatamente com aqueles definidos nos cálculos do dimensionamento. Além disso, há uma questão: dimensionar sistemas de irrigação localizada visando obter elevada uniformidade de emissão significa alcançar elevada uniformidade na produção ? Este trabalho teve como objetivo avaliar a relação entre a uniformidade de emissão de projeto e a uniformidade da produção, em sistema de irrigação por microaspersão. A análise de sensibilidade envolveu diferentes declividades, 0%, 3%, 6%, 9% e 12%, e diferentes valores de uniformidade de emissão de projeto, 60% 70%, 75%, 80%, 85%, 90% e 94%. Considerou-se um pomar de citros com dimensões de 400m por 600m, com declividade variável na direção do menor comprimento. As linhas de plantio estavam em nível, na direção da maior dimensão. O espaçamento adotado no pomar era de 7m x 4m. A linha de derivação operava sempre em declive e tinha espaçamento regular entre linhas laterais de 7m, sendo que a primeira estava a 3.5m. Observou-se maiores valores de uniformidade da vazão nos maiores valores de declividade, exceto em 12%. Quando se calculou o coeficiente de variação da produtividade utilizando a função de produção para o fator água, verificou-se uma melhoria da uniformidade em todas... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Irrigation uniformity is related to the ability of equipment to provide the same amount of water throughout the irrigated area. In irrigation systems, the design is based on the pre-established emission uniformity (EU) which is the combined result of the equipment characteristics and its hydraulic configuration. However, this desired value of the EU may not be confirmed by the final project, due to the slope of the area and the commercial diameters of the pipe. This study aimed to evaluate the uniformity of design of an irrigation system and its relationship with yield. The sensitivity analysis involved different slopes, 0, 3, 6, 9 and 12%, and different values of emission uniformity, 60, 70, 75, 80, 85, 90 and 94% . The design of trickle irrigation was applied to a citrus orchard with dimensions of 400m x 600m, with variable slope towards the shorter length. The tree rows were leveled in the larger direction and the spacing adopted in the orchard was 7m x 4m. The manifold line was always operating on a slope and had regular spacing between the lateral lines of 7m, the first of which was 3.5m. Higher discharge values were observed in the highest slope values except at 12%. When we calculated the variation coefficient of productivity using the production function for the water factor, there was an improvement of uniformity in all the combinations evaluated. Comparing the index performance evaluation, it was observed they had the same pattern performance in all combinations studied. The lowest values were obtained for the indicator emission uniformity and the largest for distribution uniformity, and the Barragan index had intermediary performance. The variation pressure coefficients ranged from 0.02 to 0.33, the flow variation coefficient ranged from 0.01 to 0.17, and production variation coefficients with 60 days of irrigation ranged from 0.0003 to 0.0125 / Mestre

Three hydrosalinity models of different complexity were evaluated against data from selected citrus orchards in the Lower Coerney River irrigation area. These models were statistically compared with field data, and found to vary in accuracy of output predictions. The simplest model, the LEACHING REQUIREMENT (LR) model, has the lowest data input requirements and produces output predictions that correlate with up to 93% of the variance in measured data. SODICS, which is theoretically more detailed and requires a greater level of detail in input, produces predictions of an accuracy equivalent to the LR model. The PEAK model was assessed in two parts, the PEAKM module simulating soil moisture and soil moisture movement was able to predict variations in moisture up to 99% of the time. The PEAKD module, which predicts solute concentrations was less effective in replicating real world conditions