Pedro Vieira de Azevedo

Análise do conforto térmico em galpões avícolas com diferentes sistemas de acondicionamento

A base deste trabalho foi a analise da influencia da tipologia e das condicoes de conforto termico ambiental em sete sistemas de acondicionamento de aviarios de frangos de corte, localizados na mesorregiao do Agreste paraibano. Os sistemas foram os seguintes: telha de amianto sem ventilacao artificial; telha de barro sem ventilacao artificial; telha de amianto com ventilacao artificial; telha de barro com ventilacao artificial; telha de amianto com ventilacao artificial e nebulizacao; telha de barro com ventilacao artificial e nebulizacao e telha de amianto com ventilacao artificial e aspersao sobre a cobertura. A avaliacao foi feita com base na temperatura do ar (TA), na umidade relativa (UR), no indice de temperatura de globo negro e umidade (ITGU) e na carga termica de radiacao (CTR) em diferentes horarios, durante o periodo de verao. Constatou-se influencia da tipologia nas condicoes de conforto termico e que em todos os sistemas os indices de conforto variaram ao longo do dia, sendo que a TA, o ITGU e a CTR, apresentaram valores considerados acima do ideal, enquanto a UR ficou dentro da zona de conforto termico.

Evapotranspiração de referência nos perímetros irrigados do estado de Sergipe

The knowledge of reference evapotranspiration (ETo) is essential for the irrigation scheduling of crops throughout the world. This work used daily meteorological data of Class A pan evaporation, maximum and minimum air temperatures, insolation, wind speed at 2 m above surface and relative humidity from 1989 to 1993 for four irrigated perimeters of Sergipe. These data were used for estimating ETo based on the following methods: Class A pan evaporation, Solar Radiation, Hargreaves & Samani, Linacre and Penman-Monteith (FAO/56). The daily values of ETo were compared to those obtained by FAO Penman-Monteith method in order to choose the best method of estimating ETo for the region. The best performance was obtained for those models which used the solar radiation as the data input. The Class A pan evaporation method did not show favorable performance in any irrigated perimeter.

Evapotranspiration and crop coefficient of irrigated cotton crop, cultivar BRS-200 Marrom

Field experiments were carried out at the EMBRAPA, Barbalha, CE, during the growing seasons of 2003 and 2005 with the objective of estimating the evapotranspiration and crop coefficient of irrigated BRS-200 Marrom cotton cultivar. For this sensors of solar radiation, net radiation, dry and wet bulbs air temperature and wind speed at the 0.30 and 1.50 m levels above crop canopy and soil heat flux were installed and data were collected by a data acquisition system. Crop (ETc) and reference (ETo) evapotranspiration were estimated by the Bowen ratio and Penman-Monteith methods, respectively, while the crop coefficient (Kc) was estimated by the ratio of ETc to ETo. The ETc changed throughout the phonological cycle of the cotton crop, with mean values of 3.8 mm d-1 in the period from emergence to 10% of soil cover (phase I), 5.0 mm d-1 in the period of vegetative growth (phase II), 5.9 mm d-1 in the period of reproductive development (phase III) and 5.4 mm d-1 in the maturation period (phase IV). The Kc may be estimated as a function of the days after emergence (DAE) as: Kc = -0.00006 DAE2 + 0.009 DAE + 0.632.

Análise da pluviometria e dias chuvosos na região Nordeste do Brasil

Rainfall daily data of 600 meteorological stations were analyzed to assess the changes in precipitation in northeastern Brazil. Maps of rainy day numbers and the coefficient of variation (CV) for rainfall and rainy days are presented. Autocorrelation function was obtained for the annual rainfall in northeastern Brazil. Results showed that the semiarid regions have a high coefficient of variation for both rainfall and rainy days than those located in northeastern coast and ´agreste´ of Brazil. The highest values of coefficient of variation are associated to the lowest values of rainfall and rainy days. The rainfall change in northeastern Brazil is smaller in rainy regions than in dry regions. The high changes in rainfall and rainy days are limiting features to the rainfed agriculture in semiarid environments. The correlograms of rainfall indicated significant trend for the limits of 95% confidence levels on some stations.

Crescimento e rendimento do abacaxizeiro nas condições climáticas dos Tabuleiros Costeiros do Estado da Paraíba

A field experiment was carried out with the pineapple, cultivar Perola, in Santa Rita in the State of Paraiba, Brazil, during the period from March, 2001 to June, 2002. The development and yield of crop under supplemental irrigation conditions was evaluated in order to obtain information for improving crop management in the region. The growth and yield variables were compatible with those obtained in other studies. The results showed that the leaf area index (LAI) reached a value of 12, 308 days after planting and the fruits with weight above 1.7 kg reached 60% of the total harvested fruits. The fruit of 2nd category, with weight between 1.3 and 1.7 kg, represented 30% of the total fruit production while the remaining 10% of fruits harvested with weight less than 1.3 kg, were considered of lower quality and sent to the juice and animal food industry. The pineapple crop, cv Perola, grown under climate and Costal Table Land soil of Santa Rita, PB, presented LAI, size of fruit and yield greater than those obtained in other regions of Brazil, even in irrigated areas.

Fluxos de energia e desenvolvimento da cultura do abacaxizeiro

The canopy of the pineapple crop changes considerably during the growing season, from a leafless stage to a fully closed canopy at the end of the productive cycle. In order to evaluate the effects of the energy balance components on the developmental stage of the pineapple crop, a field experiment was carried out from March, 2001 to July, 2002 with pineapple crop, cv. Perola, cultivated under supplemental irrigation conditions in the State of Paraiba, Brazil. The method of energy balance based on the Bowen ratio was used to obtain energy balance components during the experimental period. The energy balance components were strongly affected by leaf area index and plant height during all developmental stages of the canopy, especially the sensible heat flux. Results showed that the dry matter weight is totally independent of the energy partitioning. The sensible heat flux varied in function of the volume of water applied in irrigation during the experimental period.

Evapotranspiração e produtividade da mangueira sob diferentes tratamentos de irrigação

The objective of this study was to determine the evapotranspiration and yield as well, as the appropriate irrigation scheduling, for mango. The experimental design was in randomized blocks, with four treatments and four repetitions. The irrigation treatments were established based on the reference crop coefficient (Kcr), such as: treatment T1 (Kcr - 20%), treatment T2 (Kcr), treatment T3 (Kcr + 20%) and treatment T4 (control). The evapotranspiration of mango was obtained by the soil water balance method and the production components were also evaluated. Soil water pressure suction was measured based on twelve sets of mercury tensiometers positioned under the canopy of individual trees. Measurements were recorded three times per week at 08:00, 12:00 and 16:00 h. Throughout the mango fruiting cycle the mean daily evapotranspirations were 3.0, 3.2, 3.6 and 4.1 mm day-1 in the treatments T1, T2, T3 and T4, respectively. The maximum and minimum yields were 31.1 and 28.1 t ha-1 in the T3 and T4 treatments, respectively. The T3 treatment is more appropriate for the studied area.

Influência do calor armazenado no sistema solo-planta no balanço de energia em pomar de mangueiras

Neste estudo se objetivou a avaliacao da contribuicao do calor armazenado acima das placas de fluxo de calor no solo e no dossel vegetativo sobre os componentes do balanco de energia, no pomar de mangueiras. Os componentes do balanco de energia foram obtidos pelo metodo do balanco de energia com base na razao de Bowen. O teste t-Student foi usado para avaliar a existencia de diferenca significativa entre as medias dos componentes do balanco de energia, obtidas mediante as seguintes condicoes: (i) considerando-se o calor armazenado acima dos fluximetros e (ii) desconsiderando-se o calor armazenado acima dos fluximetros, cujos resultados indicaram que: 1) o efeito do calor armazenado no dossel vegetativo e irrelevante quando comparado com os outros componentes do balanco de energia em pomar de mangueiras; 2) o calor armazenado acima das placas de calor no solo nao interfere significativamente no calculo dos fluxos de calor sensivel e latente nem na evapotranspiracao da mangueira irrigada; 3) o fluxo de calor no solo, corrigido com o calor armazenado acima dos fluximetros, difere estatisticamente a nivel de 5% de probabilidade, daquele obtido sem a correcao do fluxo.

Risco climático para o cultivo do algodoeiro na região nordeste do Brasil

Weekly mean values of solar radiation, rainfall, evapotranspiration and air temperature were used for establishing the lower climatic risk to the cotton crop. For irrigated fields, the potential crop yield was evaluated by the cumulative growth index (CGI), while for rain-fed conditions the climatic risk was determined by the water potential deficit (WPD). Under irrigated and rain-fed conditions, the lower climatic risk occurs when cotton crop is sowing from 6 to 19 August and from the 44th (West region of Bahia state) to the 19th week of the year. From the 1st week of the year, the most suitable date for cotton sowing start in the Central region of Piaui state, reaching maximum covering area of Piaui, Rio Grande do Norte, Paraiba, Pernambuco states and North of Bahia state in the period between the 4th and the 8th week. In the South and West regions of Bahia state, the lower climatic risk is reached by cotton crop when sowing in the 10th and 46th weeks. In the northeast Coast, otherwise the cotton crop sowing is more suitable in the period from the 14th to 17th week, covering most of the coastal shore table lands from Rio Grande do Norte to Bahia states and almost the total areas of the Alagoas and Sergipe states.

Characterization of human thermal comfort in urban areas of brazilian semiarid

Experimental studies were conducted aiming to characterize the thermal conditions in urban areas of the Brazilian semiarid for identifying the level of human thermal comfort in urban areas of the municipalities of Mossoro-RN, Serra Talhada-PE, Petrolina-PE and Juazeiro-BA. The results showed that the constituent elements of urban areas contribute to human thermal discomfort index (DIT). Both the wet and dry seasons showed up an uncomfortable condition in Mossoro on May 15th and on 23rd, 2008 (rural area) and on May 25rd, 2008 (urban area). By applying Thoms equation for obtaining the DIT, it was observed that the urban areas reported thermal comfort conditions always inferior to those observed in the rural areas. The results indicate conditions of partial comfort for the all areas surveyed. However, the incidence of human thermal discomfort related to the minimum, average and maximum air temperatures are, probably associated to the formation of urban heat islands. In addition, the afforestation is an effective mechanism of mitigating the adverse effects of these structures with better quality of life to the population. Therefore, it can be stated that the Brazilian semiarid region has specific urban climate, which is influenced by the design characteristics of the urban structure and buildings.