Tecnologia do irrigâmetro aplicada no manejo da irrigação do feijoeiro / Irrigâmetro of technology applied in the irrigation management of the bean




This work was performed at the Irrigation and Drainage Experimental Area of the Agricultural Engineering Department at the Universidade Federal de Viçosa (UFV), in Viçosa, located at 20 45` S and 42 45` W, in the state of Minas Gerais, Brazil, during the period of March to October of 2007. The objectives of this study were: a) determine the crop evapotranspiration (ETc) of beans and grass-batatais; b) determine the crop coefficients (Kc) of the grassbatatais and bean plant during different stages of development; c) evaluate the Irrigâmetro performance in relation to other methods for the determination of bean crop evapotranspiration with the goal of irrigation management. Two experiments were conducted. The first included the use of twelve ground water lysimeters operating with the modified Irrigâmetro, where six lysimeters were used for measuring evapotranspiration of grass-batatais (Paspalum notatum L.) and the other for determination of evapotranspiration in beans (Phaseolus vulgaris L.). The treatments were randomized in lysimeters. Readings from the lysimeters planted with grass and beans were performed daily at 9:00 am. The daily evapotranspiration values for the grass-batatais and bean plants were determined in accordance with the crop coefficients for both the grass and bean crop under conditions of the lysimeters of constant water level operation with the modified Irrigâmetro. The reference evapotranspiration (ET0) obtained using the REF-ET computer program which was based on the Penman-Monteith FAO 56 equation was used as the basis for the modified Irrigâmetro. The second experiment was a comparative study of other methodologies of irrigation management, conducted with beans crop in an area of 0.18 ha and irrigated with a conventional sprinkling system. The management methods used were the Irrigâmetro, greenhouse standard method, class A tank, evapotraspiration estimate using the computer programs REF-ET and Irriplus. An automatic meteorology station was used which provided meteorological data to be used in the REF-ET and Irriplus computer programs. The tensiometric method was used as an indicator for irrigation, where the critical value of - 40 kPa was established. Calculation of irrigation levels was determined daily using the different irrigation management methods. The obtained results permitted the conclusion that: a) the average Kc values of grass-batatais grown in the ground water lysimeters was 1.11. b) the Kc values obtained for beans were 1.18, 1.41, and 1.58 for stages I, ,II and III of development, respectively. c) The greenhouse standard method presented an irrigation recommendation 10.1% lower to that of the Irrigâmetro, 20% greater to the hydraulic balance using the REF-ET computer program, 17.9% greater than the Irriplus computer program and 12% greater the class A tank method. Application of the Dunnett test with statistical significance of 5% showed that there was no significant difference between the irrigation management methods and the greenhouse standard method. Therefore, the Irrigâmetro performance in irrigation management for the bean crop was similar to the other methods utilized in this experiment.


engenharia de agua e solo irrigâmetro feijão common beans irrigation management irrigâmetro manejo da irrigação

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