As equações de chuvas intensas têm sido usadas como ferramenta importante para o dimensionamento de obras hidráulicas. Devido à grande carência de informações relativas às equações de chuvas intensas, o presente trabalho teve como objetivo a obtenção das relações de intensidade, duração e frequência de precipitação pluvial para o Estado do Pará, utilizando-se a metodologia da desagregação da chuva de 24 h. Foram utilizadas séries históricas de dados pluviométricos de 74 cidades do Estado do Pará, obtidas no Sistema de Informações Hidrológicas da Agência Nacional de Águas-ANA. As equações de intensidade-duração-frequência foram devidamente ajustadas e apresentaram bom ajuste, com coeficientes de determinação acima de 0,99. A maioria das estações (51,4%) apresentou intensidade de precipitação entre 90 e 110 mm h-1, para uma duração de chuva de 30 min e um tempo de retorno de 15 anos. Pode-se perceber uma concentração das maiores precipitações na região próxima ao litoral do nordeste paraense e no sudeste da Ilha do Marajó.

Com o intuito de oferecer embasamento técnico-científico para o desenvolvimento de uma irrigação de baixo custo e alto nível tecnológico, este trabalho teve como objetivo desenvolver uma equação para dimensionamento de microtubos em que a perda de carga localizada, a perda de carga ao longo do tubo e a energia de velocidade, estão representados na equação. O presente trabalho foi conduzido no Departamento de Engenharia Rural da ESALQ/USP, onde foi estabelecida, com base nos resultados dos ensaios dos microtubos, a relação entre pressão, comprimento, vazão e diâmetro para três diferentes modelos matemáticos de representação do fenômeno de perda de energia no microtubo. Dentre os modelos propostos, o que considerou a perda de carga localizada nesse fenômeno, com o coeficiente K da equação de perda carga localizada em função do Número de Reynolds (RN) foi o que melhor representou o fenômeno de perda de energia no microtubo. Foi testado, também, um modelo que não considera a perda de carga localizada e um outro que ressalta a perda de carga localizada com o coeficiente de perda de carga localizada (K) constante. A perda de carga localizada é um importante fator que deve ser considerado no dimensionamento do microtubo. Além disso, em situações de baixo NR o coeficiente de perda de carga localizada (K) não é um valor constante e, sim, uma função do NR.

A B S T R A C TSeedlings of açaí obtained from plant material native to floodplains (from Laranjeira and Muaná) and adapted to upland areas (cv. BRS-Pará and ecotype Hideo) were cultivated between March and October 2013 in a greenhouse, to test the hypothesis that water requirement for seedling production varies according to the origin of plant material. The seedlings were subjected to watering regimes corresponding to 40, 70, 100 and 130% of field capacity. Regardless of plant material, the production of vigorous seedlings was feasible only under irrigation of 100 and 130% of field capacity. The seedlings produced under 130% of field capacity showed higher plant height, stem diameter, number of leaves, total leaf area, leaf and root biomass, total plant biomass and root/shoot ratio than those produced under 100% of field capacity. The former also showed higher net CO 2 assimilation rate, lower stomatal conductance and transpiration and higher instantaneous water use efficiency. In conclusion, the water requirement to produce vigorous seedlings of açaí does not vary within plant material and more vigorous seedlings are produced under irrigation of 130% of field capacity.Respostas morfológicas e fisiológicas de mudas de açaizeiros submetidas à diferentes regimes hídricos R E S U M O Mudas de açaizeiro produzidas a partir de materiais vegetais oriundos de várzea (procedência Laranjeira e Muaná) e adaptadas às áreas de terra firme (cv. BRS-Pará e cotipo Hideo) foram cultivadas entre março e outubro de 2013, em viveiro, para testar a hipótese de que a demanda de água para a produção de mudas vigorosas varia em função da origem do material vegetal. As mudas foram submetidas a regimes hídricos correspondentes a 40, 70, 100 e 130% da capacidade de campo. Independente do material vegetal, a produção de mudas vigorosas foi viável apenas nos regimes hídricos de 100% e 130% da capacidade de campo; desses, as mudas produzidas sob 130% da capacidade de campo apresentaram maior altura, diâmetro do caule, número de folhas, área foliar total, biomassa de raízes e folhas, biomassa total e razão raiz parte aérea; além disto, apresentaram maior taxa de assimilação líquida de CO 2 , menor condutância estomática e transpiração e maior eficiência instantânea do uso da água; concluindo, a demanda hídrica para produção de mudas de açaizeiro não varia com a origem do material vegetal e a produção de mudas mais vigorosas se dá pelo uso de irrigação correspondente a 130% da capacidade de campo.

ABSTRACT:In order to provide scientific information about the irrigated cauliflower production in Northeast of Para, an experiment was installed in the Federal Rural University of Amazonia farm with the Desert hybrid under different water tensions on the ground and boron doses in the municipality of Igarapé-Açu -PA. The experimental design was a randomized block in a 4 x 4 factorial, sixteen treatments with three replications. The treatments consisted of four water tensions on the ground (15, 30, 45 and 60 kPa) as an indicative of the time to irrigate and four boron doses (0, 2, 4 and 6 kg ha -1 ). The irrigation was performed with drippers and irrigation management with tensiometers. Each plot, 4 m 2 , consisted of 8 plants located in the spacing of 1.0 m between lines and 0.5 m between plants. The hybrid is promising for cultivation in the soil and climatic conditions of the region where it was evaluated, with productivity of 17.1 t ha -1 , fresh mass of the inflorescence of 0.85 kg plant -1 , inflorescence diameter of 18 cm, in 38 kPa tension. The optimal dose of boron which ensured greater production of dry mass was 3 kg ha -1 .

Acmella oleracea (L.) R.K. is a native Amazon vegetable, known as jambu, which is widely used in regional cuisine and has aroused the interest of the pharmaceutical and cosmetic market. Thereby, this work aimed to study the effect of different soil water tensions and nitrogen rates on Jambu cultivation in the State of Pará. The experiment was conducted in a greenhouse for 30 days in 2016 testing Jamburana cultivar in a 10 × 10 cm spacing in the experiment. The experimental design was based on randomized blocks in a 4 × 4 factorial scheme with three replications. The treatments consisted of four soil water tensions (12, 18, 24 and 30 kPa) adjusted using drip irrigation, and four doses (0, 50, 100 and 150 kg ha-¹) of nitrogen. The analyzed variables were fresh mass, plant height, productivity and water use efficiency. There was no interaction between soil water tensions factors and nitrogen rates for all variables. The results showed that the best water tension in the soil and nitrogen dose that provided better development and productivity of jambu were 18 kPa and 79 kg ha-¹, respectively.

ABSTRACT:In Brazil, there is a lack of information on the production of carrots via drip irrigation, both from the perspective of appropriate irrigation management and in relation to the economic feasibility of the technology of production. This study aimed to assess the economic feasibility of drip-irrigating carrot crops based on appropriate irrigation management. The experiment was established in open field beds in the experimental area at the Agricultural Department/UFLA, from June to October 2008. The experimental design was randomized blocks in a 2 x 6 factorial scheme, with four replications. The treatment levels were two carrot cultivars, the hybrid Optima F1 and the non-hybrid Alfa Tropical, and six soil water-tension values, i.e., 15, 25, 35, 45, 60 and 75 kPa. The economic analysis of the irrigated farming was based on production costs theory. According to this analysis, for all the treatment levels, variable costs were the costs that most affected the final cost of the carrots harvested. Under the experimental conditions, we recommend irrigation upon reaching a soil water tension of 15 kPa when using the Nantes cultivar and a tension of 25 kPa for the Nayarit F1 hybrid to obtain higher profitability in the productive activity. The costs of the resource variables were the largest final costs of carrot production in all the treatments, emphasizing the required inputs.

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ABSTRACT The aim of this study was to establish the best concentrations of growth regulators for in vitro cultivation of jambu for a subsequent elaboration of an efficient micropropagation protocol. After sterilized, the seeds were inoculated on different media (MS, ½MS and water-agar) for in vitro germination. Nodal segments of in vitro germinated jambu seedlings were used as explants in the micropropagation with different concentrations of 6-benzylaminopurine (BAP) (0.0; 0.125; 0.25; 0.50 and 0.75 mg L-1) and callus induction with 2.4- dichlorophenoxyacetic acid (2.4-D) (0.0; 0.25; 0.50; 0.75 and 1.0 mg L-1) on Murashige & Skoog’s (MS) medium. The highest germination rates were obtained on MS medium with better seedling development and greater height (3.7cm). In micropropagation, the best treatment was obtained on 0.125 BAP (T2), with an average of 2.2 sprouts/explant, average height of 2.4 cm and vigorous sprouts. In callus induction, all treatments with 2.4-D had developed friable calluses in 30 days and using doses of 0.25 and 0.50 mg L-1 provided greater fresh matter. The induction of friable callus and the root production occur without supplementation of exogenous growth regulator.