Luciana Sandra Bastos de Souza

Variação do balanço de radiação e de energia da cana-de-açúcar irrigada no semiárido brasileiro

The objective of this work was to analyze the variations in the magnitudes and partition of the radiation and energy balance components, obtained during the growth period of the irrigated sugarcane (variety RB92579). The experiment was carried out in Juazeiro-BA, located in the Brazilian semiarid region. The sensible (H) and the latent (LE) heat fluxes in the air were estimated by means of the Bowen ratio energy balance (BREB). The crop growth was also monitored. In a preliminary analysis of this method, it was verified that 62.7% of the collected data presented physical consistence to be used for estimating the H and LE components. It was observed that the mean value of the Rn/Rg ratio was equal to 59±5%, with smaller values occurring at the beginning and at the end of sugarcane crop cycle, while the magnitude of long wave radiation balance (BOL) was intensified when the leaf area index (LAI) was reduced. Also, it was noticed that the mean value of the albedo was 23±3% and that 81% of the available energy was destined to the latent heat flux, while the sensible heat in the air (H) and in the soil (G) represented 16 and 3%, respectively.

Biometrics of the sugarcane shoot during irrigated ratoon cycle in the Submedio of the Vale do São Francisco

The productivity of sugarcane in the Submedio of the Vale do São Francisco has been presenting superior performance due to the use of irrigation. In this way, information regarding the crop growth can be used for improving crop management. Thus, the objective of this work was to carry out a biometrics analysis of the irrigated sugarcane, seeking to supply the absence of information of this crop in the region. The experiment was conducted in the district of Juazeiro-BA using the variety RB92579 during the ratoon cycle. Two types of biometrics analysis were performed, one of them was destructive, where plants were sampled and conducted at the laboratory, and another one was no destructive, in which the variables are monitored in field. Based on the results, it was possible to verify that the crop presented high tillering (15.2 shoot m-2). The sugarcane lodging affects the dynamics of the stalks height, which reached final value of 421 ± 22 cm. However it did not demonstrate direct impacts on the length (13.6 ± 2.4 cm), diameter (2.5 ± 0.2 cm) and volume of the internodes (68.8 ± 19.5 cm3), as well as in the yield. The leaf appearance rates were 0.0079 leaves oCd-1, in the Interval I, and 0.0018 leaves oCd-1, in the Interval II. The maximum leaf area (423 ± 39 cm2) depends of the position in the stalk (no15) and it responds mainly to the leaf length (maximum value 146 ± 6 cm), because the width (~4.2 ± 0.2 cm) tended to stabilize along the cycle. The leaf area index presented a positive correlation with the number of expanded green leaves and with the leaf area.A produtividade da cana-de-acucar no Submedio do Vale do Sao Francisco tem apresentado desempenho de destaque devido a utilizacao de irrigacao. Dessa forma, a obtencao de informacoes sobre o crescimento das plantas nessas condicoes e essencial, uma vez que podem ser utilizados para adequacao do manejo da cultura. Assim, objetivou-se com este trabalho realizar uma analise biometrica da parte aerea da cana-de-acucar irrigada, visando suprir a ausencia de informacoes desta cultura na regiao. O experimento foi realizado no municipio de Juazeiro-BA, com a variedade RB92579, no ciclo de cana soca. Realizaram-se dois tipos de analise, sendo uma destrutiva, onde plantas foram amostradas e conduzidas ao laboratorio, e outra de natureza nao destrutiva, na qual as variaveis foram monitoradas em campo. A partir dos resultados, foi possivel constatar que a cultura apresentou altos padroes de perfilhamento (15,2 perfilhos m-2). O tombamento da cana-de-acucar afeta a dinâmica da estatura dos colmos, a qual atingiu valor final de 421 ± 22 cm. Porem, nao demonstrou impactos diretos sobre os padroes de comprimento (13,6 ± 2,4 cm), diâmetro (2,5 ± 0,2 cm) e volume dos internodios (68,8 ± 19,5 cm3), bem como no rendimento. A taxa de aparecimento foliar foi de 0,0079 folhasoCd-1, no Intervalo I, e de 0,0018 folhas oCd-1, no Intervalo II. A area maxima da folha (423 ± 39 cm2) depende da sua posicao no colmo (no15) e responde, principalmente, ao comprimento foliar (maximo valor de 146 ± 6 cm), logo que a largura maxima (~4,2 ± 0,2 cm) tende a se estabilizar ao longo do ciclo. O indice de area foliar apresentou uma correlacao positiva com o numero de folhas verdes abertas e com a area das folhas.

Eficiência do uso da água das culturas do milho e do feijão-caupi sob sistemas de plantio exclusivo e consorciado no semiárido brasileiro

This study aimed to analyze the productivity, the water use efficiency, and the economical viability for corn and cowpea crops on single and intercropping systems in the Brazilian semiarid region. The experiment was carried out at Petrolina, State of Pernambuco. The crops, in different planting systems (single and intercropping), underwent the five blades of irrigation, ap - plied at the flowering stage of cowpea to 40 days after sowing. Combining the settings of cultivation system and the differ - ent depths of irrigation, crops of maize and cowpea were subjected to 15 different treatments. To evaluate the performance of crops in the different treatments indicators that consider the production response of crops and the performance of the application of water in the production system were used. The grain yield responses of maize and cowpea to the soil water content were reduced in intercropped plantations, in relation to single cropping. Even so, in economic terms, the adoption of maize-cowpea proved to be more advantageous in all treatments.

Climate change scenarios and their impacts on milk production in northeastern states of Brazil

A pecuaria leiteira e uma atividade de grande importância no nordeste brasileiro, podendo ser afetada de forma direta e indireta, caso as atuais previsoes climaticas sejam confirmadas ate o final do seculo. O objetivo deste trabalho foi estimar os impactos das mudancas climaticas sobre a producao leiteira nos estados de Alagoas, Bahia e Sergipe. Os valores do indice de temperatura e umidade (ITU), do declinio da producao de leite (DPL) e da reducao do consumo alimentar (RCA) de vacas leiteiras foram calculados para os cenarios climaticos B1 e A1F1 do IPCC. Utilizou-se um modelo multiplicativo para estimar o efeito das alteracoes de temperatura sobre os valores normais da umidade relativa do ar. Com base em ambos os cenarios do IPCC, as regioes produtoras, situadas no norte e litoral do estado da Bahia e areas litorâneas dos estados de Alagoas e Sergipe, serao afetadas expressivamente em decorrencia do aumento do estresse termico, com reducoes marcantes na producao de leite e no consumo alimentar, especialmente de animais com alto potencial genetico de producao. Este cenario pode afetar as atuais regioes produtoras dos estados nordestinos, de forma que a exploracao leiteira seja limitada aos animais com baixo desempenho produtivo.

Radiation balance in Caatinga ecosystem preserved for a year drought in semiarid Pernambucano

extremely useful for a better understanding of the interaction between the savanna and the atmosphere under natural climatic conditions.

Agrometeorological research on forage cactus and its advances in Brazil

Despite being more resilient than agriculture, the performance of the livestock sector depends greatly on the seasonality of the weather variables, which directly affect the supply and quality of the forage. Many forage species have an accumulation of biomass limited to the rainy season, which restricts the activity. Agrometeorology is the science that studies the effect of meteorological and climatological conditions on the agricultural performance of the species and field activities. The progress of this science to a crop allows the understanding of its interaction with the environment and the measurement of technical data, valuable for the improvement of agricultural resilience, planning, decision making, and expansion of financing and rural insurance policies. As a result, it is important to understand the plant-environment interaction to identify the factors that most influence the performance of crops, to elaborate the climatic risk zoning. Knowledge of phenology improves agricultural management and determines the cutting time. The definition of the crop coefficient helps in water management. The application practices of improving agricultural resilience such as selecting the most suitable cultivars, mulching, intercropping and minimum irrigation use ensure maximization of yield. This knowledge was recently raised for the forage cactus, the most cultivated forage cactus in the world. Hence, the objective of this study was to review the advances of agrometeorology information in Brazil on forage cactus for optimization of irrigation management and maximization productivity of the crop.

Gross water demand of forage cactus on future scenarios of climate change in the State of Pernambuco

Objective to evaluate the water demand for irrigation of forage cactos in future scenarios B2 and A2 of air temperature, rainfall and carbon dioxide levels (CO2) in State of Pernambuco. 292 observation posts of Pernambuco and surrounding States with observed and estimated data were used. Increased projections were considered and reduction of 10 and 20% of the rainfall about local normal climatological, associated with two climate change scenarios (B2 and A2) of the meteorological variables (maximum and minimum air temperature), influencing the duration of the crop cycle and atmospheric demand. In addition, it was assumed the effect of concentration of CO2 in the atmosphere, affecting in stomatal resistance 22% and 4% on leaf area index of the reference surface (grass), and their effects were extrapolated to the forage cactus, through the crop coefficient. The increase of air temperature in the light of the future scenarios of Revista Brasileira de Geografia Física vol. 08, n.06 (2015) 1628-1643.

Evaluation of the method of FAO data 56 Monteith Penman with missing data and of alternative methods in the estimation of reference evapotranspiration in the Submedium Valley of San Francisco

Objective to evaluate the performance of the Penman Monteith method parameterized on the 56 FAO Bulletin (PMFAO56) with the absence of data and of alternative methods for the estimation of reference evapotranspiration in the Submedium Valley of San Francisco. Weather variables for the period March 2003 to April 2008 were used of five automatic stations belonging to the network of Embrapa semi-arid. In the evaluation of this method were considered to be different combinations as the lack of measurement of meteorological variables (radiation balance, global solar radiation, temperature and relative humidity, and wind speed), and alternative methods of Hargreaves and Samani, Jensen and Haise and Makkink. The performance was analyzed by means of indices and statistical errors. The results revealed that the PM-FAO56 has good estimates of ETo values when the absence of data is limited to the variables of relative humidity, for the estimation of the water vapor partial pressure, and, or, the wind speed, as soon as the square root of the square of the average error was less than 0.65 mm day, when there is no data of these two variables at the same time. The estimation of the radiation balance values despite the good precision and accuracy in most weather stations (r > 0.93 and angular coefficient < 1.19) raises the miscalculation of ETo in the region. Alternative methods of Revista Brasileira de Geografia Física vol. 8, n.6 (2015) 1644-1660.

Índices Morfofisiológicos e Uso de Radiação Solar por um Cultivo de Cana-de-Açúcar Irrigada no Semiárido Brasileiro (Morphophysiological Indices and Radiation Use by an Irrigated Sugarcane Crop in the Brazilian Semi-Arid)

Esse estudo tem como objetivo avaliar o padrao de crescimento da variedade de cana-de-acucar RB92579, por meio de indices morfofisiologicos e de parâmetros de uso da radiacao, durante o ciclo de cana-soca, sob irrigacao, no Semiarido brasileiro.