Parámetros para la evaluación del impacto de los morteros de revestimiento en las condiciones acústicas de los espacios históricos

Se realiza una evaluación del efecto que produce en el acondicionamiento acústico de recintos históricos los diferentes tiois de morteros utilizado en el revestimiento

Light intensity and type of container on producing Cassia grandis L. f. seedlings

ABSTRACTThis study aimed to determine the effects of the luminosity and type of container on producing Cassia grandis seedlings. Thus, in a substrate composed by topsoil + wood powder (1:1) the seedlings were grown into plastic tubets containing 0.3 dm3 of such substrate, or into plastic pots containing 1.0 dm3 of the same substrate, and subjected to 50 and 25% shading or full sunlight. The assessments were performed every two weeks by measuring plant height and stem diameter, during eight weeks period. At the end of this period, the leaf area, dry mass of shoots and roots, the ratio between height of plant/diameter of stem, and the Dickson quality index were also assessed. The experiment was carried out in a completely randomized design with treatments arranged in a 3 x 2 factorial [3 luminosity levels (50, 25% shading and full sunlight) x 2 types of containers (plastic tubets and clay pots)] with four replicates of 10 seedlings each. Means were compared by Tukey test at 0.05 probability level and adjustments for the non-linear regression polynomial curves for the assessed characteristics were computed in function of time. Shadings of 25 and 50% were the best alternatives to luminosity; and the tubets were the most suitable containers for production of Cassia grandis seedlings

Germination and initial development of Simira gardneriana seedling under water stress and at different temperatures

ABSTRACT The germination of seeds is affected by many factors, including water availability and temperature. This study aimed to evaluate the effects of water stress and different temperatures on germination and initial development of S. gardneriana M. R. Barbosa & Peixoto seedlings. The experiment was carried out in a completely randomized design, in a 7 x 4 factorial scheme, with seven potentials (0; -0.1; -0.2; -0.3; -0.4; -0.5 and - 0.6 MPa) and four temperatures (25, 30, 35 and 20-30 °C), with four replicates of 25 seeds. The analyzed variables were germination, percentage of normal seedlings, germination speed index, seedling length (shoot and root) and dry weight (shoot and root). There is a decrease in the germination and vigor of the seeds as the water potential decreases, being less affected under the temperature of 25 °C and very accelerated at 35 °C. The tolerance of S. gardneriana seed germination to water stress is variable between the temperatures and limiting to the formation of normal seedlings from the potential -0.5 MPa at temperatures of 25 to 30 °C and -0.4 and -0.2 MPa for 20-30 and 35 °C, respectively

Water use of cowpea under deficit irrigation and cultivation systems in semi-arid region

The resilience of crops to drought depends heavily on the cultural practices adopted, which can have a direct effect on water use efficiency. The aim of this study was to assess the influence of irrigation intervals on the growth, water consumption and water use efficiency of cowpea crops (cv. BRS Guariba) under conventional and no-tillage systems. The experiment was carried out in the semi-arid region of Rio Grande do Norte, Brazil, using a split-plot in a randomised complete block design, with four replications. Treatments consisted of two cultivation systems in the whole plots (conventional and no-tillage) and six irrigation intervals in the subplots (2, 6, 10, 14, 18 and 22 days) which were applied at full bloom. The biomass of the different parts of the plant, leaf area and leaf area index were assessed at 64 days after sowing (DAS) and grain yield, water consumption and water use efficiency at 70 DAS. No-tillage is a promising cultivation technique for cowpea crops, promoting higher grain yield and water use efficiency under semi-arid conditions. This system allows cowpea cultivation with irrigation intervals of 10 or 14 days, with no or small reduction in yield, respectively.A resiliência das culturas à seca depende fortemente das práticas culturais adotadas, as quais podem ter um efeito direto sobre a eficiência de uso da água. O objetivo deste estudo foi avaliar a influência de turnos de rega sobre o crescimento, consumo de água e eficiência de uso da água do feijão-caupi (cv. BRS Guariba) nos sistemas de plantio direto e convencional. O experimento foi conduzido na região semiárida do Rio Grande do Norte, Brasil, utilizando-se blocos completos casualizados, no esquema de parcelas subdivididas, com quatro repetições. Nas parcelas, foram avaliados dois sistemas de plantio (convencional e direto) e, nas subparcelas, seis intervalos de irrigação (2, 6, 10, 14, 18 e 22 dias) que foram aplicados em pleno florescimento. Foram avaliados a biomassa das diferentes partes da planta, a área foliar e o índice de área foliar, aos 64 dias após a semeadura (DAS), além do rendimento de grãos, consumo de água e eficiência de uso da água, aos 70 DAS. O plantio direto é uma técnica de cultivo promissora para a cultura do feijão-caupi, promovendo maior rendimento de grãos e eficiência de uso da água sob condições semiáridas. Este sistema permite o cultivo de feijão-caupi com turnos de rega de 10 ou 14 dias, com nenhuma ou pequena redução na produtividade, respectivamente

‘Jurema-de-embira’ seed germination under water stress and at different temperatures

ABSTRACT The process of water imbibition by the seed depends on temperature and water availability, which according to the absorbed water retention capacity will determine the success of the germination process. Thus, this study aimed to investigate the effects of water stress on the germination and vigor of ‘jurema-de-embira’ seeds under different temperatures. The experimental design was completely randomized in a 7 x 4 factorial scheme (osmotic potential and temperature) with four replicates of 25 seeds each. The osmotic potentials of 0, -0.1, -0.2, -0.3, -0.4, -0.5 and -0.6 MPa at temperatures of 25, 30 and 35 °C and alternated of 20-30 °C, under photoperiod of 8 h, were evaluated. Germination percentage, germination speed index, shoot and root length, shoot dry biomass, root dry biomass and total biomass were evaluated. Water stress negatively affected the germination and vigor of ‘jurema-de-embira’ seedlings from the potential of -0.2 MPa on, whose effects are more evident at the temperature of 35 ° C. The alternated temperature of 20-30 °C allowed greater tolerance to water stress for the germination of ‘jurema-de-embira’ seeds

Emergência e crescimento inicial de plântulas de albízia submetidas à irrigação com água salina

Objetivou-se, com este trabalho, avaliar o efeito de diferentes concentrações de sais na água de irrigação sob a emergência e o crescimento inicial de plântulas de albízia (Albizia lebbeck (L.) Benth.). O experimento foi desenvolvido em casa de vegetação do departamento de Ciências Vegetais da Universidade Federal Rural do Semiárido, Mossoró, RN, usando-se o delineamento inteiramente casualizado, com seis tratamentos e quatro repetições, com 24 sementes em cada parcela. Os tratamentos foram constituídos das concentrações salinas 0,68 (água de abastecimento); 1,5; 3,0; 4,5; 6,0 e 7,5 dS m-1, obtidas através da adição de NaCl em água. As variáveis avaliadas foram: porcentagem de emergência de plântulas, índice de velocidade de emergência, comprimento da parte aérea, comprimento de raiz, número de folíolos, condutividade elétrica acumulada do substrato, índice de conteúdo de clorofila, massa seca da raiz, do caule, das folhas e total. O aumento da salinidade na água de irrigação interfere negativamente na emergência e no crescimento inicial de plântulas de albízia, sendo recomendado água com concentração salina até 1,5 dS m-1, caracterizando esta espécie como glicófita, sensível à salinidade

Water use of cowpea under deficit irrigation and cultivation systems in semi-arid region

ABSTRACT The resilience of crops to drought depends heavily on the cultural practices adopted, which can have a direct effect on water use efficiency. The aim of this study was to assess the influence of irrigation intervals on the growth, water consumption and water use efficiency of cowpea crops (cv. BRS Guariba) under conventional and no-tillage systems. The experiment was carried out in the semi-arid region of Rio Grande do Norte, Brazil, using a split-plot in a randomised complete block design, with four replications. Treatments consisted of two cultivation systems in the whole plots (conventional and no-tillage) and six irrigation intervals in the subplots (2, 6, 10, 14, 18 and 22 days) which were applied at full bloom. The biomass of the different parts of the plant, leaf area and leaf area index were assessed at 64 days after sowing (DAS) and grain yield, water consumption and water use efficiency at 70 DAS. No-tillage is a promising cultivation technique for cowpea crops, promoting higher grain yield and water use efficiency under semi-arid conditions. This system allows cowpea cultivation with irrigation intervals of 10 or 14 days, with no or small reduction in yield, respectively