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Made available in DSpace on 2015-03-05T16:20:40Z (GMT). No. of bitstreams: 0 Previous issue date: 16 / Nenhuma / O presente estudo inserido na linha de pesquisa “Diversidade e manejo de Vida Silvestre” objetivou investigar a ocorrência de artrópodes e a seletividade de lambdacialotrina em populações de inimigos naturais, em áreas de arroz irrigado. Os experimentos foram realizados em Cachoeira do Sul, Eldorado do Sul e Capivari do Sul nos anos agrícolas 2007/08 e 2008/09. Para o levantamento dos artrópodes, em cada localidade foram utilizadas quatro parcelas orizícolas sem tratamentos com inseticidas. As amostragens foram realizadas durante as três fases do cultivo das plantas, utilizando-se rede de varredura. Na análise da seletividade , as áreas orizícolas foram compostas por duas subáreas, sendo que uma delas foi tratada com 150mL/ha-1 de lambdacialotrina, enquanto a outra ficou isenta do produto. As avaliações foram realizadas aproximadamente aos 2, 15, 30 e 45 dias após a aplicação do inseticida, conforme as datas de amostragem nas localidades. Os resultados revelaram que a ocorrência dos artrópodes variou conforme

In the Zapotitan Valley near San Andres, El Salvador, Central America, an experiment was conducted to determine the availability of residual soil N to corn grown during the rainy season. This was an extension of an experiment conducted during the preceding dry season. The variables of the dry season experiment were irrigation method, crop, and rate of fertilizer N application. Soil N03-N and NH4-N were determined by soil sample analysis to a soil depth of 120 em by 30 em depth increments. The samples were taken at the end of the dry season experiment and again at harvest time of the wet season experiment. Yield of corn grown during the rainy season was measured. The results indicate the following: (1) soil N03-N alone was an efficient indicator of residual soil N; (2) there was a linear increase of soil N03-N with N applied four months previously at the beginning of the dry season crops; (3) soil sampled to the 30 cm depth was sufficient to estimate availability of the residual N; (4) corn yields increased linearly with the increase of soil N03-N; (5) the measurement of residual soil N03-N can be used as a soil text index in connection with N prediction equations for estimating fertilizer N requirements. The measurements of soil N03-N can, therefore, increase the efficiency of fertilizer use in a wet-dry tropical climate.

To obtain the profiles of dry bulb and wet bulb temperature, specific humidity, q, and air density, ρ, to a height of 200 meters above the ground, a precise lightweight thermocouple psychrometer was designed. To lift the thermocouple psychrometer and the attached wires in obtaining the ρq profiles, a rigid polyethylene balloon augmented with 5.5-feet outdoor or 100-g meteorological balloons were used. Using the height dependent eddy exchange coefficient and a one-dimensional time-dependent profile model, the nighttime variations of ρq as a function of height were predicted and compared with observed values. It was found that the general shape of the eddy exchange coefficient, K(Z), was approximately the same as found in recent literature.

Multispectral aerial and satellite remote sensing plays a major role in crop yield prediction due to its ability to detect crop growth conditions on spatial and temporal scales in a cost effective manner. Many empirical relationships have been established in the past between spectral vegetation indices and leaf area index, fractional ground cover, and crop growth rates for different crops through ground sampling. Remote sensing-based vegetation index (VI) yield models using airborne and satellite data have been developed only for grain crops like barley, corn, wheat, and sorghum. So it becomes important to validate and extend the VI-based model for tuber crops like potato, taking into account the most significant parameters that affect the final crop yield of these crops.

Arid and semi-arid countries are facing the exhaustion of their water resources and are being forced to use saline water (brackish groundwater and drainage water) for irrigated agriculture. The result is often disastrous as extensive productive regions become salinized. Nevertheless, there is potential to expand irrigated agriculture through the increasing use of saline waters for irrigation. / This study presents an analysis of the performance of a transient state, model for numerical simulation of water and solute transport, known as LEACHM-C. It is assessed for areas where saline water may be an option for crop production. The model estimates the salt and water balance of a soil profile given certain irrigation and crop rotation strategies. / First, the predictive capability of the model was successfully tested using one year of data from a field experiment in a dry region of India. / Second, potential usefulness of the LEACHM-C model as a tool in the planning of reclamation activities was examined for a semi-arid basin in Syria. (Abstract shortened by UMI.)

Thesis (M.S. - Soil and Water Science)--University of Arizona. / Includes bibliographical references (leaves 183-199).

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

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / A agricultura irrigada se intensificou nas Ãltimas dÃcadas nas regiÃes Ãridas e semiÃridas, aumentando a produtividade das culturas e, consequentemente a necessidade do uso de fertilizantes e agroquÃmicos para suprir as necessidades das plantas e controle de pragas e doenÃas. Com o objetivo de analisar o impacto dessas prÃticas na fertilidade do solo, foi realizado o estudo em uma Ãrea com agricultura irrigada, localizada no perÃmetro irrigado do Baixo Acaraà - CE, abrangendo trÃs diferentes usos: mata em regeneraÃÃo (mais de 10 anos), cultivo de goiabeira (quatro anos) e cultivo de banana (seis anos). Foram abertas duas trincheiras nas Ãreas de mata e banana, para fins de caracterizaÃÃo e classificaÃÃo do solo, e coletado amostras de solo nas profundidades de 0 a 20 e 20 a 40 cm em 100 pontos georreferenciados e distribuÃdos irregularmente na Ãrea (50 na Ãrea com banana, 30 na Ãrea com goiaba e 20 na mata). Foram analisados os atributos quÃmicos: pH H2O, pH KCl, Ca2+, Mg2+ Na+, K+, SB, H+Al, CTC, V%, P, N, PST, COT, fraÃÃes hÃmicas( C-HUM, C-FAH e C-FAF), micronutrientes (Fe, Cu, Mn, Zn) e fraÃÃes granulomÃtricas (areia, silte e argila). A variabilidade e a dependÃncia espacial foram analisadas utilizando tÃcnicas de geoestatÃstica e krigagem. Os resultados evidenciam que a maioria das variÃveis apresentou dependÃncia espacial moderada para a camada de 0 - 20 cm e forte para a camada de 20 â 40 cm, refletindo as prÃticas de manejos e de adubaÃÃo que tendem a tornar mais aleatÃria a variabilidade espacial dos atributos quÃmicos na Ãrea. Os atributos Ca, Na e PST apresentarem variabilidade espacial e temporal com aumento gradativo dos teores com o tempo de cultivo. Os teores de sÃdio triplicaram passando 0,16 a 0,48 cmolc dm-3, enquanto para a PST o aumento foi ainda maior, passando de 2,5 a 8,5% e de 2,5 a 12,5% para as camadas de 0 -20 cm e 20 â 40cm, respectivamente. O uso da geoestatÃstica e interpolaÃÃo de dados por krigagem possibilitou a identificaÃÃo de Ãreas com diferentes necessidades de adubaÃÃo fosfatada e potÃssica, para as duas culturas, mostrando que a utilizaÃÃo de teores mÃdios de K e P do solo para a prÃtica de adubaÃÃo, aumenta os custos de produÃÃo, alÃm de gerar impactos ambientais, ou deficiÃncias nutricionais pelo desbalanÃo entre os nutrientes do solo. O cultivo de bananeira e goiabeira aumentou os teores de nutrientes do solo em relaÃÃo à Ãrea com mata, porÃm à preciso a adoÃÃo de medidas preventivas para reduzir os impactos decorrentes do uso continuado de fertilizantes e defensivos agrÃcolas aliados à prÃtica de irrigaÃÃo. / Irrigated agriculture has intensified recent decades in arid and semiarid regions, increasing crop productivity and hence the need for the use of fertilizers and chemicals to meet the needs of plants and controlling pests and diseases. In order to analyze the impact of these practices on soil fertility, the study was conducted in an area with irrigated agriculture, irrigation district located in the Baixo Acaraà - CE, covering three different uses: forest regeneration (more than 10 years), cultivation of guava (four years) and banana cultivation (six years). We opened two trenches in the areas of forest and banana, for purposes of characterization and classification of the soil, and soil samples collected at depths of 0 -20 and 20 to 40cm in 100 georeferenced points and irregularly distributed in the area (50 in the area with banana, 30 in the area with guava and 20 in the natural vegetation). We analyzed the chemical attributes: pHH2O, pHKCl, Ca2+, Mg2+ Na+, K+, SB, H + Al, CEC and V%, P, N, sodium saturation, TOC, micronutrients (Fe, Cu, Mn, Zn), humic fractions (C-HUM, C-and C-FAF FAH) and granulometric fractions (sand, silt and clay). The variability, spatial dependence and time were analyzed using geostatistics and kriging techniques. The results show that most of the variables showed moderate spatial dependence for the 0-20cm depth and strong spatial dependence for the depth 20-40 cm, reflecting the practices and fertilization managements tend to become more random spatial variability of chemical properties in the area. Attributes Ca, Na and sodium saturation showed spatial and temporal variability of the levels with a gradual increase with time of cultivation. The sodium concentration tripled passing from 0.16 to 0.48 cmolc dm 3, while the sodium saturation was further increased going from 2.5 to 8.5 and from 2.5 to 12.5 of 0 -20 and 20 cm - 40 cm, respectively. The use of geostatistics and kriging interpolation of data enabled the identification of areas with different needs for phosphate and potash, to both cultures, showing that the use of average levels of P and K soil fertilization to practice increases the production costs, and generate environmental, or nutritional deficiencies by imbalance of soil nutrients. The cultivation of banana guava increased levels of soil nutrients in relation to the area with woods, but it is essential to adopt preventive measures to reduce impacts resulting from the continued use of agricultural fertilizers and pesticides coupled with the practice of irrigation.

Les politiques concernant les périmètres irrigués en Tunisie sont passées d’un modèle privilégiant une gestion centralisée, axée prioritairement sur l’accroissement de l’offre d’eau, à un modèle plus décentralisé et participatif, basé sur une meilleure maîtrise des usages de l’eau par les agriculteurs. La thèse a pour objectif d’analyser les mutations qui sont intervenues dans les périmètres irrigués de la région de Nadhour au Nord de la Tunisie, suite à l’évolution de leur mode de gouvernance et dans un contexte de féminisation de l’agriculture. Elle vise à mettre en évidence l’impact des dynamiques au sein des organisations d’irrigants et des exploitations sur les inégalités entre les acteurs des systèmes irrigués et particulièrement entre hommes et femmes. Les principales observations issues de recherches effectuées à l’échelle nationale et locale dans le cadre d’une approche pluridisciplinaire sont les suivantes.Le processus de décentralisation de la gestion des périmètres semble inachevé et ne parait pas maîtrisé par les organisations d’irrigants qui n’ont pas été associées à la définition des règles qui régissent le fonctionnement des périmètres. Les structures d’encadrement étatiques conservent un pouvoir important.On assiste à une augmentation des inégalités entre agriculteurs dans les périmètres irrigués. Une minorité d’exploitants disposant de plus fortes capacités ont des stratégies offensives et parviennent à tirer parti des opportunités offertes par les systèmes irrigués. Une majorité de petits et moyens exploitants éprouve des difficultés à faire face aux exigences des systèmes d’irrigation. Parmi ceux-ci, une partie d’entre eux ont des stratégies de retrait de l’agriculture irriguée. Les difficultés de la petite et moyenne paysannerie sont liées en partie à l’inadaptation des politiques agricoles de type productiviste menées depuis l’Indépendance et au dysfonctionnement de la gouvernance des périmètres irrigués.Bien que les femmes exercent une proportion croissante des tâches de production dans l’agriculture irriguée, elles ne sont pas associées aux prises de décision dans les organisations d’irrigants qui sont dirigées par les hommes. Les savoir-faire et l’expérience des femmes dans l’agriculture irriguée sont peu pris en compte dans des milieux où il y a une prédominance de structures patriarcales. La faible implication des femmes affaiblit les capacités d'organisations d’irrigants impliquées dans la gouvernance des périmètres irrigués. Mais, la contribution des femmes à l’entretien des familles progresse du fait de l’accroissement de leur rôle dans la production agricole et des revenus tirés de leurs activités extra-agricoles. Elles acquièrent des compétences nouvelles dans le cadre de l’adhésion à des organisations féminines informelles et revendiquent un accès régulier à l’eau et une participation aux prises de décision dans les organisations d’irrigants. / Policies concerning the irrigated perimeters in Tunisia developed gardually from a model privileging centralized management, first and foremost centered on the increase in the offer of water, to a more decentralized and participative model, based on a better control of famer's use of water. The thesis aims to analyze the changes observed in the irrigated perimeters of the Nadour region in the northern Tunisia resulting from new governance and in the context of the of a more feminized agriculture. The thesis also aims to highlight the impact within irrigant organizations and farms, on dynamics on the inequalities between actors of irrigated systems and particularly between men and women. The main observation and stemming from the research carried out at a national and local scale within the framework of a multi – disciplinary approach are as followThe process of decentralization in the management of the perimeters seems incompleted and not mastered by the irrigants organizations who weren't ask to participate to the definition of the perimeters' governance. In parallel, State run supervision institutions remain powerful.There are growing inequalities among famers in the irrigated perimeters. A minority of owners having stonger capacities has offensive strategies and manages to benefit from the opportunities offered by the irrigated systems. A majority of small and average farm owners has difficulties of coping with the requirement of these same systems. Thus some of them consider giving up irrigated agriculture. Indeed the difficulties of smal and average farms are partly due of the maladjustment of the productivist agricultural policies carried out since independance as well as to the dysfunction of the irrigated perimeters' governance.Although, women play a growing role in the irrigated role in the agricultural production, in the men-run irrigant organizations they are excluded from the decision making process. Womens' experience and know-how in irrigated agriculture are taken little into account in this typical patriarchal milieu. Thus women's low involvement weakens the capacities of the irrigant organizations taking part in the governance of the irrigated perimeters. However, due to higher participation in agricultural production et extra-agricultural incomes, women's economical support to their family living expenses in increasing. By joining informal women organizations they acquire new competences and claim regular access to water and the possibility to take part in the irrigant organizations'decision-making process.