Navegando por Autor "Pereira, Silvio B."
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Item Arugula production as a function of irrigation depths and potassium fertilization(Revista Brasileira de Engenharia Agrícola e Ambiental, 2017) Giovanelli, Luan B.; Pereira, Silvio B.; Delazari, Fábio T.; Santos, Márcio L. dos; Silva, Derly J. H. da; Freitas, Elis M. deArugula is a vegetable that has gained more highlight in the consumption, being rich in potassium, sulfur, iron, omega-3 and vitamins A and C. Availability of water and nutrients are limiting factors for production of this crop. In this context, the objective of this study was to evaluate the production of arugula subjected to different irrigation depths and potassium fertilization. The experiment was conduct between August and September 2015. The experimental design was completely randomized in split-plot scheme. Irrigation depths L1, L2, L3 and L4 (25, 50, 75 and 100% of crop evapotranspiration, respectively) represented the plots and potassium doses K1 and K2 (200 and 400 kg ha-1, respectively) represented the subplots. Although the highest yield was obtained with highest irrigation depth and highest potassium dose, it is recommended the cultivation of arugula with the lowest irrigation depth and the lowest potassium dose, considering the higher value of water use efficiency for this treatment.Item Calibration and validation of the swat hydrological model for the mucuri river basin(Engenharia Agrícola, 2018-01) Pereira, Silvio B.; Almeida, Rafael A.; Pinto, Daniel B. F.Hydrological models are becoming more and more widespread, mainly due to their capacity to simulate the impact of environmental changes on water resources. In this way, the aim of this study was to calibrate and validate the SWAT model for the soil and climatic conditions of the Mucuri River Basin, located in the Northeast region of the States of Minas Gerais, Brazil. The SWAT-CUP software module SUFI2 was used to analyze the sensitivity, calibration and validation of the model. The calibration was performed in an intermediate fluviometric station and the validation in five other located: three upstream, one downstream and one independent from the calibration point. It was evidenced for the study area that the parameters referring to the basic flow processes were more sensitive. The model obtained a good adjustment with an overestimate tendency of 15%. In general, the SWAT model, using SWAT-CUP was good and adequate in terms of its calibration performance and validation of the flow simulation in the Mucuri River Basin by the determination coefficients, Nash-Suttclife efficiency and percentage of trend.Item Desprendimento e arraste do solo pelo escoamento superficial(Revista Brasileira de Engenharia Agrícola e Ambiental, 2003-09) Pereira, Silvio B.; Pruski, Fernando F.; Silva, Demetrius D. da; Matos, Antonio T. deO presente trabalho teve como objetivo analisar o efeito de diferentes vazões de escoamento superficial e declividades nas perdas de solo resultantes. Na realização do experimento utilizou-se um canal, no qual foi colocada uma camada de solo (Latossolo Vermelho-Amarelo) com espessura de 12 cm. Para a análise da capacidade de desprendimento e arraste de partículas de solo pelo escoamento superficial a aplicação de água foi feita de maneira uniforme ao longo de toda a largura do canal. Foram utilizadas as declividades de 2, 4, 6, 8 e 10%, e seis vazões distintas para cada uma destas declividades. Em cada teste foi determinada a perda de solo pelo método direto e, com base nos dados de taxas de perdas de solo obtidos a partir das diferentes declividades e vazões de escoamento superficial utilizadas nos testes foram ajustadas equações de regressão. Os resultados obtidos permitiram as seguintes conclusões: a) a declividade apresentou um efeito mais expressivo nas taxas de perdas de solo do que a vazão; b) observou-se tendência de declínio das taxas de perdas de solo com o tempo; e c) a equação linear foi a que melhor se ajustou aos dados de perdas de solo ao longo do tempo para a declividade de 2%, enquanto, o ajuste da equação do tipo potencial se mostrou mais adequado para as declividades de 8 e 10%. Nas declividades de 4 e 6%, entretanto, não se observaram diferenças expressivas entre os ajustes das equações linear e potencial.Item Development of an annual drought classification system based on drought severity indexes(Anais da Academia Brasileira de Ciências, 2019) Lima, Rafael P. C.; Silva, Demetrius D. da; Pereira, Silvio B.; Moreira, Michel C.; Passos, Jéssica B. M. C.; Coelho, Clívia D.; Elesbon, Abrahão A. A.In order to characterize the occurrence and intensity of droughts in the Doce River Basin, as well as to develop a system for its classification, four different drought indexes were evaluated: Percent of Normal Precipitation (PNP), Deciles Method (DM), Rainfall Anomaly Index (RAI) and Standardized Precipitation Index (SPI). The indices were calculated annually, based on precipitation data from 89 rainfall stations of the Brazilian National Water Agency (ANA). Nine analysis units (AUs) were determined in the basin and the Thiessen Polygons method was used to obtain the average precipitation in the respective drainage areas. The indices were calculated for each AU and then related to the drought intensity classes. An overall classification of the indices was proposed for the drought classification system for a 30-year base period, from 1985 to 2015. The most critical hydrological years of the Doce River Basin in relation to the drought were 1994/1995, 2000/2001 and 2014/2015, the latter being the most critical of the last 30 years. The results show that the annual drought classification system proved to be efficient in the identification of events, allowing to verify that the Doce River Basin presents a severe climatic drought condition, on average, every seven years.Item Estimates of monthly and annual evaporation rates and evaporated volumes per unit time in the Tucuruí- PA and Lajeado- TO hydroelectric power plant reservoirs based on different methods(Engenharia Agrícola, 2018-01) Coelho, Clívia D.; Silva, Demetrius D. da; Sediyama, Gilberto C.; Moreira, Michel C.; Pereira, Silvio B.; Lana, Ângela M. Q.Evaporation rates in reservoirs influence the volume of water available for multiple uses. Thus, the objective of this study was to estimate the evaporation rates and the evaporated volumes per unit time in the Tucuruí-PA and Lajeado-TO reservoirs based on the methods in Linacre (1993), Kohler et al. (1955), Morton (1983), Bruin & Keijman (1979) and Penman (1948) method was adopted as the standard. The mean annual evaporation rates in the Tucuruí and Lajeado reservoirs, estimated by the Penman method, were similar, with values of 1,784 mm and 1,882 mm, respectively. None of the alternative analyzed methods could be used to estimate the mean annual evaporation in the Tucuruí and Lajeado reservoirs and could not replace the Penman method. However, the Linacre (1993) and Bruin & Keijman (1979) methods could be used to estimate monthly evaporation during the dry season in Tucuruí. The mean evaporated volume per unit time and the mean net evaporated volume per unit time in the Tucuruí reservoir correspond to 120% and 50%, respectively, of the total water demand in the Tocantins-Araguaia region, while the mean evaporated volume per unit time and the mean net evaporated volume per unit time in the Lajeado reservoir correspond to 120% and 50%, respectively, of the total water demand in the basin.Item Response of bell pepper crop subjected to irrigation depths calculated by different methodologies(Revista Brasileira de Engenharia Agrícola e Ambiental, 2018) Silva, Gustavo H. da; Ferreira, Mariane G.; Pereira, Silvio B.; Delazari, Fábio T.; Silva, Derly J. H. daWater must be supplied to a crop in the proper amount and in a timely manner. Vegetables require a good water availability in soil during their entire cycle. Thus, it is very important the implementation of an irrigation management and accurate estimation of water requirement. The objective of this work was to evaluate the effect of five irrigation depths estimated by the dual-Kc and single-Kc methodologies on the characteristics of growth, production and water use efficiency in the pepper crop. A randomized block design was adopted in a split plot arrangement. The effect of five irrigation depths (50, 75, 100, 125 and 150% of crop evapotranspiration - ETc) was evaluated in the plots, and the methodologies were evaluated in the subplots. It was evaluated the root dry matter, total fruit production, leaf temperature, number of aborted flowers and water use efficiency. The interaction between both effects was not significant for any of the variables. The effect of methodology was observed only on the number of aborted flowers. The effect of the irrigation depths was significant on all variables. The irrigation depths that lead to the best agronomic characteristics were superior to 100% of ETc. The ratio between the irrigation depths estimated by single-Kc and dual-Kc methodologies was 1.14. Single-Kc methodology and irrigation depth of 143% ETc were more suitable for the horticulturist. The most efficient irrigation depth in the use of water was 105% ETc.Item Water seasonality in granting permits and impact of irrigation in the Dourados River basin, MS, Brazil(Revista Brasileira de Engenharia Agrícola e Ambiental, 2017-07) Pereira, Silvio B.; Ramos, Diovany D.; Arai, Fabiane K.; Santos, Felipe A. dos; Carnevali, Thiago de O.The objective of this study was to evaluate water seasonality in the process of granting permits and the impact of irrigation in the Dourados River basin. For that, the hydrological behavior of the basin was analyzed. The minimal streamflows (Q7,10 and Q95), irrigation withdrawal flow (Qr) and the percent variation of the grant flows relative to monthly seasonal period in relation to the monthly withdrawal flow were obtained. The results allowed to verify that using criteria based on the monthly streamflow allows for better management of water use, because it allows for greater utilization of this resource in times with high water availability and imposes a realistic restriction during critical periods. The average annual water withdrawal for irrigation in the basin during the studied period was on the order of 2.99 m3 s-1, and the withdrawal flow in the month of highest demand (August) was 5.95 m3 s-1.