Índices de desempenho da irrigação pressurizada com base na distribuição logística de probabilidades

Abstract

In a growing demand for water and energy resources, at the same time with the Society pressure over the agribusiness, especially the irrigated agriculture, adopt more advanced and efficient growing technics to minimize the environmental impacts using less power and water resources, keeping the profitability of the land. To reach out these subjects, it is mandatory that the irrigations systems after installed get a complete evaluation and keep its operations monitored, maintaining high efficiency of the system along the time, allowing the grower to use less water and energy. This study aimed to propose two uniformity of distribution coefficients, the first using the average deviation of the collected water and the second adopting the low quarter average of the collected water, both basing on the logistics probabilistic distribution. Also, this study proposed a group of performance equations that allow evaluates the efficiency of distribution, the water lost by deep seepage and the area underirrigated by the nonuniformity, based on the logistics probabilistic distribution. To evaluate the goodness-of-fit of the proposed uniformity of distribution equations, that was used the date of 57 single sprinkle in-field tests with medium sized sprinklers models Agropolo/NY e Naan/5024, jet angle of 12°, in a wind condition and simulating 90 overlapping with different spacing. In the mechanical lateral move system that was performed 29 in-field tests using sprinklers Senninger model I-Wob with 10 psi pressure regulator. In the drip irrigation system that was performed 26 indoor tests with a RainBird model XF-SDI, nominal diameter of 16 mm (13.65 mm internal), nominal flow 2.27 L.h-1 , autocompensating and with operating pressure between 6,02 and 42,22 wcm. The uniformity coefficients based on the logistics probability distribution were the best to describe the Christiansen Uniformity coefficient (CUC) and the Distribution Uniformity (DU) to the 29 in-field tests of the mechanical lateral move system and to the 26 indoor tests of the RainBird XF-SDI drip irrigation system. To the 90 overlapping of the single sprinkler in-field test the uniformity coefficient based on normal probability distribution were those that achieved the best goodnessof-fit with de CUC and DU obtained in-field. The group of performance equations that allow evaluates the efficiency of distribution, the water lost by deep seepage and the area underirrigated by the nonuniformity, based on the logistics probabilistic distribution introduced a new and more accurate method to evaluate different irrigation systems that those existing on the literature.