Engenharia Agrícola - Artigos
URI permanente para esta coleçãohttps://locus.ufv.br/handle/123456789/11739
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Item Use of PVC pipes to determine bulk density for irrigation management(Revista Ciência Agronômica, 2019-01) Pereira, Silvio Bueno; Oliveira, Rubens Alves de; Assis, Igor Rodrigues de; Oliveira, Reginaldo Miranda; Matsinhe, Daniel ZefaniasIrrigation has a great importance in the production of food, and it is responsible for consuming a large part of the water used by human activities. This makes the rational management of water use fundamental for sustainable food production. For this purpose, the determination of bulk density is important and needs to be obtained with the simplest, least onerous methods possible, while maintaining precision and accuracy. Therefore, the objective of this work was to evaluate the use of PVC pipes of different dimensions to determine bulk density. For comparison purposes, the volumetric ring, paraffin clod, beaker and excavation methods were also used. Deformed and undisturbed soil samples of different granulometries were collected at the depths of 0.025-0.075, 0.050-0.100, 0.075-0.125 and 0.100-0.150 m. The PVC pipes had diameters of 0.040, 0.050, 0.060 and 0.075 m and heights of 0.10, 0.15, 0.20 and 0.25 m. The bulk density results for each PVC pipe dimension were compared with those of the traditional methods by the unpaired t-test at 5% significance. For soils with a clayey or very clayey texture, the 0.040 m diameter and 0.15 m high PVC pipe presented the best results, with values closer to those of the standard method. For soils with a medium and sandy texture, the best results were found when a PVC pipe with a diameter of 0.060 m and a height of 0.15 m was used.Item Water needs and equivalence relations for different irrigated crops in the São Francisco basin(Revista Ciência Agronômica, 2018-07) Silva, Felipe Bernardes; Pereira, Silvio Bueno; Martinez, Mauro Aparecido; Silva, Demetrius David da; Vieira, Nayara Paula AndradeThe present work was performed by applying the principal component analysis, in order to compare the water needs of banana, mango, grape, sugarcane, maize and beans crops in different regions of the São Francisco river basin, aiming to identify the climate elements that most influence the reference evapotranspiration (ET 0) in the locations of Pirapora-MG, Jaíba-MG, Barreiras-BA and Petrolina-PE. In addition, the locations with more similarities, according to the evaluated parameters, were verified by applying cluster analysis, and the equivalence relations between the studied crops were determined by integrating the parameters related to the climatic elements and the characteristics of crops and soils. Based on the principal components analysis, it was observed that the most significant climate elements for ET 0 estimation were different for each place. The model with two components explained 90%, 88%, 95% and 97% of the total variance, respectively for the locations of Pirapora, Jaíba, Barreiras and Petrolina. Because it is in a semi-arid climate region, Petrolina showed high crop water needs, a behavior proven with the cluster analysis. The equivalence relations allowed comparing the water needs for the studied crops, providing, in general terms, a parameter comparison between the crops, and specifying which one will be more adequate depending on the water availability in the São Francisco basin.Item Reference evapotranspiration estimation by the Irrigameter in Southern Tocantins State, Brazil(Revista Brasileira de Engenharia Agrícola e Ambiental, 2017-05) Giovanelli, Luan B.; Oliveira, Rubens A.; Oliveira-Filho, Jair C.; Baptestini, Júlio C. M.; Delazari, Fábio T.; Sediyama, Gilberto C.The choice for the most appropriate method to estimate evapotranspiration depends on the availability of meteorological data, required level of precision and cost of equipment acquisition. For this estimate, the Irrigameter is simple to operate, precise and economically viable to farmers. In addition, it collaborates in the application of the necessary water depth to crops, thus avoiding unnecessary energy consumption, environmental degradation, and increasing crop yield and improving crop quality. In this context, the objective of this research was to estimate the reference evapotranspiration using the Irrigameter, for the climatic conditions of the Southern Tocantins state, Brazil. The experimental design was completely randomized with Irrigameters operating with seven water heights in the evaporator, as treatments, with three replicates. The reference evapotranspiration was obtained by FAO-56 Penman-Monteith method. For the analyzed climatic conditions, the water height in the evaporator recommended to estimate the reference evaporation in the spring is 3.4 cm; summer, 4.0 cm; fall, 3.8 cm; and winter, 2.3 cm.Item Uso do irrigâmetro para estimar a evapotranspiração de referência com base no método do lisímetro de lençol freático constante(Engenharia na Agricultura, 2010-06-09) Tagliaferre, Cristiano; Oliveira, Rubnes Alves de; Sediyama, Gilberto Chohaku; Cecon, Paulo Roberto; Materan, Franklin José ValbuenaOs objetivos deste trabalho foram avaliar o Irrigâmetro para estimar a evapotranspiração de referência (ET0) e comparar os métodos de FAO-Penman-Monteith, FAO-Penman Modificado, FAO-Radiação, Hargreaves-Samani e Tanque Classe A, em relação ao método do lisímetro de lençol freático constante. Os dados de evapotranspiração de referência (ET0), obtidos com o Irrigâmetro e com os demais métodos, foram comparados com os valores medidos no lisímetro de lençol freático constante, operando com Irrigâmetro modificado, em intervalos de um, três, cinco e sete dias. Os resultados mostraram que o Irrigâmetro apresentou desempenho satisfatório para estimar a ET0, em todos os intervalos de tempo estudados, com comportamento semelhante ao das estimativas proporcionadas pelo método de FAO-Penman Modificado. Assim, o Irrigâmetro pode ser utilizado para o manejo da água na agricultura irrigada, com as vantagens adicionais de custo relativamente baixo, alta praticidade e não envolver cálculos. Os demais métodos estudados superestimaram os valores da ET0, obtidos pelo método do lisímetro de lençol freático constante, tendo o Tanque Classe A apresentado comportamento contrário.Item Análise do coeficiente e o desempenho do irrigâmetro e a influência dos elementos do clima na estimativa da evapotranspiração(Engenharia na Agricultura, 2011-02-24) Oliveira, Ednaldo Miranda; Oliveira, Rubens Alves; Sediyama, Gilberto Chohaku; Cecon, Paulo Roberto; Drumond, Luis César DiasAt the Federal University of Viçosa, in Viçosa, MG, has developed a device evapopluviometric called Irrigameter, which allows measuring evapotranspiration, providing the right time to irrigate and the time of operation of an irrigation system or the speed of movement. In this research, the objectives were: (a) determine the Irrigameter coefficient (K I ), monthly, in the highest 1, 2, 3, 4, 5 and 6 cm of water level in evaporimeter (b) assess the performance of Irrigameter to estimate evapotranspiration under conditions of Alto Paranaíba-MG, in August 2008 to May of 2009, and (c) examine the effects of monthly meteorological variables in the interactions of the reference evapotranspiration estimated by Irrigameter operating with different heights of the level of water in evaporimeter. The experiment was mounted in a completely randomized design with six treatments and three replications. The levels of water in evaporimeter to estimate the evapotranspiration of reference were: 4.1, 4.0, 3.6, 3.8, 3.3, 3.0, 2.5, 3.3, 3, 0 and 2.9 cm for the months of August, September, October, November, December, January, February, March, April and May, respectively. For the path analysis, the climatic factors that had high correlation with the estimate of the evapotranspiration of Irrigameter were the relative humidity for the months of August and January, minimum temperature and relative humidity for the month of September, maximum temperature and relative humidity, for the month of October and minimum temperature for the month of May.