RESUMO

Soccer field grass can be compared to highly sensitive crops regarding water deficit and must be irrigated throughout the year to provide decent conditions for use. For this, efficient irrigation systems are necessary to save water and energy, and this is possible, provided that they are evaluated. Therefore, this paper evaluated the water distribution uniformity, by different methodologies, for an irrigation system installed in a grass soccer field. Also, the influences of multiple spacings between sprinklers and meteorological factors on the final results were assessed. The irrigation system had Falcon 6504 sprinklers, operating at the pressure of 320 kPa. Six field essays were conducted considering overlaying water depths originated from the same irrigation system considering spacings between sprinklers varying from 6 m x 6 m, 6 m x 9 m, 9 m x 9 m, 9 m x 12 m, 12 m x 12 m, 12 m x 15 m, 15 m x 15 m, 15 m x 18 m, 18 m x 18 m, 18 m x 21 m, 21 m x 21 m, 21 m x 24 m, 24 m x 24 m, 24 m x 27 m, 27 m x 27 m, 27 m x 30 m and 30 m x 30 m. The uniformity coefficients used were: Christiansen uniformity coefficient (CU), distribution uniformity coefficient (DU), absolute uniformity coefficient (UA), statistical uniformity coefficient (US), Hart uniformity coefficient (UH) and HSPA standard efficiency (UHSPA). Meteorological data were obtained during the essays. Wind speed caused reduction in the length of the water jet applied by the sprinkler and also caused a bigger effect on the water distribution uniformity. Both CU and UH showed higher values compared to the other coefficients. The increase in the spacing between the sprinklers resulted in reduced water distribution coefficients. To comply with technical and economic criteria, an arrangement of 12 m x 15 m between the Falcon 6504 sprinklers, operating at a 320 kPa pressure, is recommended.

Assuntos

RESUMO

Irrigation systems must be assessed periodically to verify equipment quality and the need for adjustments. For this, precipitation test kits are necessary. However, commercially available kits have as their main disadvantage the high cost. Therefore, this study aimed to develop an alternative low-cost precipitation kit and verify its efficiency compared to an available commercial brand. The validation test was carried out at the Laboratory of Hydraulics of the Federal University of Viçosa (UFV) using a conventional sprinkler system organized in a quadrangular arrangement. Water collections were carried out within two hours using a grid of plastic collectors spaced at 3 × 3 m and installed at 0.7 m above the ground. The coefficient of determination (R2 ), uniformity coefficients, application efficiency, and thematic maps of the spatial variability of the applied irrigation depth were compared between kits and used for the validation of measurements. The results showed a high agreement between the developed (GESAI) and a commercial kit (Trademark) (R2 = 0.9849), and a high spatial agreement between the collected water depths. Therefore, the GESAI kit is a low-cost alternative for the assessment of irrigation systems.(AU)

Os sistemas de irrigação devem ser avaliados periodicamente para a verificação da qualidade do equipamento e a necessidade de ajustes. Para isso, kits de ensaios de precipitação são necessários, entretanto, os kits comercialmente disponíveis apresentam como principal desvantagem o elevado custo. Assim, o presente trabalho teve como objetivo elaborar um kit de precipitação alternativo de baixo custo e averiguar a sua eficiência frente a marca comercial disponível. O ensaio de validação foi realizado no Laboratório de Hidráulica da Universidade Federal de Viçosa (UFV), utilizando um sistema de aspersão convencional, disposto em um arranjo quadrangular. As coletas de água foram realizadas no período de duas horas, com auxílio de uma malha de coletores plásticos espaçados em 3 x 3 m e instalados a 0,7 m acima do solo. Para comparação e validação das medições foram utilizados o coeficiente de determinação (R²), coeficientes de uniformidade, eficiência de aplicação e mapas temáticos da variabilidade espacial da lâmina aplicada entre os kits. Os resultados mostraram que houve elevada concordância entre o kit desenvolvido (GESAI) e o kit comercial (Trademark) (R² = 0,9849) e uma concordância espacial elevada entre as lâminas coletadas. Portanto, recomenda-se o uso do kit GESAI como uma alternativa de baixo custo para a avaliação de sistemas de irrigação.(AU)

Assuntos

RESUMO

O tempo de uso de sistemas de irrigação por pivô central pode resultar em alteração de suas características hidráulicas, necessitando de avaliações periódicas para manter a uniformidade de distribuição de água em níveis aceitáveis. Objetivou-se, neste trabalho, avaliar as condições de funcionamento e desempenho de dezesseis pivôs centrais, localizados em onze municípios de Goiás e no Distrito Federal. Estimou-se o coeficiente de uniformidade de Heermann & Hein - CUH e uniformidade de distribuição - CUD, variação da lâmina coletada em relação à projetada e os fatores que interferem no desempenho dos equipamentos. Dos pivôs avaliados, quatro (25 por cento) apresentaram CUH inadequado (< 80 por cento) e três (18,75 por cento) apresentaram CUD inadequado (< 70 por cento). A lâmina média coletada foi superior à projetada em três e inferior em treze pivôs, com diferença maior que 10 por cento em apenas um pivô. A maioria dos pivôs avaliados necessita de manutenção para solucionar algum dos seguintes problemas: bocais com vazão diferente da considerada adequada para alguns intervalos dos equipamentos, emissores total ou parcialmente obstruídos ou danificados, ausência de pendurais, reguladores de pressão danificados, vazamentos em vários pontos da lateral e velocidade de deslocamento em campo diferente da indicada no relé porcentual.

The time of use of the center-pivot irrigation system may result in alteration of the hydraulic characteristics, frequent evaluations being needed to maintain the efficiency of water distribution at acceptable levels. The aim of this work was to evaluate the conditions of the use and the performance of sixteen center pivots, located in eleven municipal districts of Goiás State and Federal District, Brazil. The Heermann & Hein - CUH coefficient of uniformity and coefficient of distribution - CUD, variation between the collected and projected depth and verification of the main factors that influenced the performance were evaluated. Among the evaluated pivots, four (25 percent) presented inadequate CUH (< 80 percent) and three (18.75 percent) presented inadequate CUD (< 70 percent). The average depth applied was higher than the projected in three and lower in thirteen pivots, with the difference higher than 10 percent in only one pivot. Most of the evaluated pivots need maintenance to solve the following problems: emitters with flow rate different from the flow considered appropriate for some intervals of the equipments; emitters totally or partially clogged or damaged; absence of suspension strings; damaged pressure regulators; leaks in several points and speed displacement different from the observed on the relay percentile.