ABSTRACT The aim of this study was to assess how microclimate variables and irrigation affect the growth of sugarcane. The experiment was conducted using the VAT90-212 cultivar in the Semi-arid region of Brazil. The microclimate was monitored and by quantifying the irrigation depth. Nine campaigns were carried out in the field to collect morphological and biomass data. The data were subjected to descriptive statistics, so as to generate the mean values and/or sum between the campaigns. Using the correlation coefficient, the extent, sign and significance of the relationship between the response and explanatory variables were evaluated. The direct or indirect effects of the explanatory variables on the response variables were identified by path analysis. There was a significant correlation between microclimate variables and the morphological and biomass variables of the sugarcane, with a strong contribution from the intercepted fraction of the photosynthetically active radiation, the wind speed and soil temperature. The negative correlation with irrigation suggests that excess water impaired the growth dynamics of the crop. It is concluded that the growth of sugarcane is closely related to its capacity to intercept radiation, to the wind, thermal regime of the soil and irrigation management.

ABSTRACT The study aimed to determine the evapotranspiration (ETc) of the mango cv. ‘Palmer’ over two productive cycles, analyzing water-use efficiency (WUE) and crop water productivity (CWP) to propose average crop coefficient (Kc) values for improving irrigation management under cultivation conditions in the Low-Middle São Francisco Valley. The study was conducted from July 2019 to May 2021 in a commercial ‘Palmer’ mango orchard in Petrolina, State of Pernambuco, Brazil. Micrometeorological data was collected throughout the experimental period. The crop evapotranspiration (ETc) was determined using Bowen ratio energy balance (BREB), and then the Kc, WUE, and CWP were determined. The highest ETc values occurred during the floral induction phase (5.14 ± 0.85 mm day-1), with a Kc of 0.85; however, the lowest values were observed during the fruit maturation phase (3.60 ± 0.73 mm day-1), with a Kc of 0.91. Average water consumption per cycle was 1445 mm, with a daily average of 4.39 mm day-1. WUE and CWP were 16.9 and 24.5 kg ha-1 mm-1, respectively. Average Kc values of 0.81, 0.76, 0.85, 0.90, 0.95, and 0.91 are recommended for the vegetative growth, rest period and shoot maturation, floral induction, flowering, fruit development, and fruit maturation phases, respectively.

O estudo de fontes alternativas de energia ao óleo diesel mineral, como o biodiesel, com origem renovável, é importante para o meio-ambiente e diversificação da matriz energética. Neste estudo foram levantados o consumo específico de combustível, o valor calórico do combustível e a eficiência do conjunto motor gerador da marca BRANCO em função de cargas resistivas, sob as seguintes proporções volumétricas entre o óleo diesel mineral com biodiesel: 0% (B0), 20% (B20), 40% (B40), 60% (B60) e 100% de biodiesel (B100). Para o ensaio utilizou-se motor de 7,36 kW, com gerador elétrico acoplado de 5,5 kW. As cargas utilizadas, 0,5 kW; 1,0 kW; 1,5 kW e 2,0 kW foram elevadas até 5,0 kW, oriundas de um dinamômetro de cargas resistentes. Assim, o desempenho do conjunto para cargas abaixo de 1,5 kW mostrou-se menor, pelo maior consumo específico de combustível (CEC), e redução na eficiência do conjunto motor gerador para a faixa de potência. Para as proporções de biodiesel B40, B60 e B100 os resultados descreveram redução no valor calórico e aumento do CEC. Portanto, realizando comparação das proporções de biodiesel com o óleo diesel, a proporção B20 substitui parcialmente o óleo diesel, sem perdas significativas do desempenho do motor gerador.

The study of mineral diesel alternatives, such as biodiesel, a renewable fuel, is important for the environment and to diversify energy sources. This study evaluated an engine-generator BRANCO brand. Specific fuel consumption, calorific value and the overall efficiency as a function of the system load was measured, using diesel oil and biodiesel blends. The biodiesel proportions in the composition were 0% (B0), 20% (B20), 40% (B40), 60% (B60), and 100% (B100). The engine that was used during the test has a power of 7.36 kW, and the electric generator was 5.5 kW. The group was submitted to resistive loading, in the range: 0.5 kW, 1.0 kW, 1.5 kW; growing up to 5.0 kW. The results have shown that, when operating at lower loads (less than 1.5 kW), the engine-generator performance decreased, while the specific consumption increased, leading to an efficiency reduction. The biodiesel proportions B40, B60 and B100 described reduction in caloric value and increased the specific fuel consumption. Therefore, comparing the proportions of biodiesel with diesel oil, the proportion B20 replaced diesel oil without significant losses in engine-generator performance.