Papers by Rubens Duarte Coelho
RESUMO: O objetivo deste trabalho foi realizar a estimativa de um índice de estresse hídrico (IEH... more RESUMO: O objetivo deste trabalho foi realizar a estimativa de um índice de estresse hídrico (IEHC) para a cultura do híbrido tomate cereja (Lycopersicum Solanum var. cerasiforme.), sob diferentes tratamentos de irrigação e condições meteorológicas. O experimento foi conduzido em uma área experimental do
Agricultural Water Management
Experimental Agriculture
Summary Water scarcity due to global warming can increase the water demand for upland rice at cri... more Summary Water scarcity due to global warming can increase the water demand for upland rice at critical stages of crop development. However, there is little research on cultivar responses to this scenario and technologies that enhance water use efficiency (WUE). To determine the influence of water stress at and after flowering stages of drip-irrigated upland rice cultivars on physiology, yield, and WUE, a shelter experiment was conducted using a randomized block design with a split-plot arrangement of treatments. Three modern and one traditional cultivar were subjected to five irrigation managements: 100% of the field capacity considered the reference management (RM), 70 and 40% of the RM at the flowering stage, and 70 and 40% of the RM at the grain-filling stage. In general, the modern cultivars tended to maintain higher photosynthetic rate, stomatal conductance, transpiration, leaf water potential, and lower crop water stress index compared to the traditional cultivar under water s...
Revista Brasileira de Engenharia de Biossistemas
For grasses and other crops in general, soil water potential has been widely studied to determine... more For grasses and other crops in general, soil water potential has been widely studied to determine if there is a deficit or excess of water content in the soil. However, the plant water absorption process is not only modulated by soil water potential but also by the combination of meteorological, soil depth, and crop canopy factors, which could be elucidated through water relations responses. The objective of this work was to compare the water relations of grass species established in different soil depths and subjected to water stress. Santo Agostinho (Stenotaphrum secundatum), Esmeralda (Zoysia japonica), Tanzania (Panicum maximum) and Tifton 85 (Cynodon spp.) were used in this trial. The four species of grasses were tested in four different soil rooting depths: 10, 20, 30 and 40 cm. The grasses were irrigated at soil moisture field capacity level, until the time of imposing the water stress period. Soil depth had a direct influence on leaf water potential and soil water potential....
Revista Brasileira de Engenharia de Biossistemas
Irrigation is a useful tool to achieve a better productivity and quality foods, which contributes... more Irrigation is a useful tool to achieve a better productivity and quality foods, which contributes to a higher efficient use of agriculture land. Drip irrigation is characterized by higher application efficiency, providing an efficient control of the irrigation depth required. Moreover, it has advantages such as lower evaporation loss and higher crop yields when associated with fertigation. However, dripper clogging is pointed out by several authors as the main limiting factor for a rapid adoption of drip irrigation on a larger scale. Emitter clogging susceptibility depends basically on five parameters: water quality, filtration system, fertilizer quality, labyrinth architectural layout and maintenance procedures. The adoption of chemical treatments helps to control biological agents and precipitates, making it possible to minimize the risk of clogging. This paper aims to understand how drip clogging process occurs, providing scientific arguments and support on the development of a s...
Journal of Agricultural Studies, 2020
Leaf area estimation is a very important indicator in studies related to plant anatomy, morpholog... more Leaf area estimation is a very important indicator in studies related to plant anatomy, morphology and physiology, and in many cases, it is a fundamental criterion to understand plant response to input conditions. Although there are leaf area prediction models have been produced for some plant species, a leaf area estimation model has not yet been developed for the zucchini. The objective of this paper was to determine the leaf area based on destructive and non-destructive methods for zucchini. The accuracy of measurement methods was evaluated and compared to determinations of the leaf area by the scanning integration method (LICOR equipment LI 3100C), considered as standard procedure. Non-destructive methods consisted of digital photography and measurement of leaf dimensions (width and length) based on ImageJ software. The destructive methods used were a) leaf area integrator LI-3100C, b) determination of leaf mass and c) weighing of leaf discs punched from the leaves. According to...
Engenharia Agrícola, 2016
The tariff flags on Brazil came into force in January 2015, applied to all electrical distributio... more The tariff flags on Brazil came into force in January 2015, applied to all electrical distribution agents of the national interconnected system (SIN) and all final consumers are being charged for this new model. Given this, the cost of electricity in irrigation suffered representative additions involving searches of alternatives, such as the use of diesel engines. This study aimed to analyze the costs and the total annual costs of pumping with diesel and electric operation in 3 regions of Brazil, considering the application of the tariff flags. We concluded that the Southeast region (SE) features an hourly cost of electricity above the Central-West (CO) and the Northeast (NE) regions at any adopted tariff, regardless of the time of pumping and the use of diesel engines in irrigation is feasible in terms of distances from the electrical grid that can range from 2.8 to 72.4 km, the first being the most favorable condition in the Southeast with the operation of 4 months per year with fertirrigation, in conventional tariff and red flag is the less favorable in the Northeast with 10 months/year operation with/without fertirrigation, in bohemia blue and green flag tariff.
Engenharia Agrícola, 2017
In Brazil, the conventional center pivot is widely used for irrigation of agricultural crops and ... more In Brazil, the conventional center pivot is widely used for irrigation of agricultural crops and its use has grown continuously. However, when improperly managed, it facilitates the development of diseases in all parts of the plant, with a direct effect on productivity, besides favoring losses of water by evaporation. The drip may be an alternative, since it minimizes the losses and does not wet the aerial parts of the plants, thereby reducing the incidence of diseases. A new system called localized mobile drip irrigation (IRGMO) is being developed in an attempt to combine the practicality and rusticity of the center pivot with the efficiency and water savings of the dripping irrigation systems. This fusion system is the central pivot with drip irrigation system for water distribution in the soil surface. This study aims to present a calculation methodology for the design of IRGMO system and compare it with conventional systems. It is concluded that this methodology allows the design of the IRGMO and that this new technology allows a savings of approximately 99% in a number of drip tubes compared to the conventional system with fixed drip irrigation lines in the field.
Anais do III Inovagri International Meeting - 2015, 2015
RESUMO: O objetivo deste trabalho foi realizar a estimativa de um índice de estresse hídrico (IEH... more RESUMO: O objetivo deste trabalho foi realizar a estimativa de um índice de estresse hídrico (IEHC) para a cultura do híbrido tomate cereja (Lycopersicum Solanum var. cerasiforme.), sob diferentes tratamentos de irrigação e condições meteorológicas. O experimento foi conduzido em uma área experimental do
Resumo: O trabalho teve como objetivo o uso da análise multivariada, visando à redução da dimensi... more Resumo: O trabalho teve como objetivo o uso da análise multivariada, visando à redução da dimensionalidade do conjunto de variáveis físico-hídricas, de diferentes solos do Nordeste do Estado do Paraná, de modo a facilitar a interpretação da interdependência entre elas. O experimento foi desenvolvido mediante utilização de uma malha regular de 36 pontos amostrais, em três solos: um Nitossolo Vermelho distroférrico e dois Latossolos Vermelhos distróficos; sob diferentes manejos. Os dados foram submetidos à análise de componentes principais, para transformação em novas variáveis, e em seguida à geoestatística, para quantificar o grau de dependência espacial dos componentes principais e da taxa de infiltração básica de água no solo. Com a análise de componentes principais, houve uma redução de treze variáveis físico-hídricas do solo para apenas duas novas variáveis, que foram porosidade do solo e taxa de infiltração, as quais explicaram 78,40% da variação dos dados. Palavras-chave: análise de componentes principais, atributos do solo, disponibilidade de água Multivariate analysis and geostatistics for hydro-physical variables of different soils Abstract: The research aimed the use of multivariate analysis, in order to reduce the dimensionality of the hydro-physical variables set of different soils in the Northwestern Paraná, to facilitate the interpretation of the interdependence between them and also to identify the similarity between the soils. The experiment was conducted in a regular grid of 36 sampling points, in three soils: an Alfisol and two distrophic Oxisols; under different managements. The data were subjected to the principal component analysis, to transformation in new variables, and after to the geostatistics, to quantify the spatial dependence degree of the major components and of the soil water infiltration rate. The principal component analysis supported in understanding of the differences and similarities among the hydro-physical variables of the soil. With the principal components analysis, there was a reduction from thirteen soil hydro-physical variables to two new variables, that were soil porosity and infiltration rate, which explained 78.4% of the variation in data.
Irriga, Dec 20, 2022
Farmers employing trickle irrigation frequently need to change irrigation block operations over t... more Farmers employing trickle irrigation frequently need to change irrigation block operations over the years (parcel combinations), because of plant renovations in certain areas of the irrigated field or the adoption of precision irrigation. It is worth emphasizing the importance of this software for the pre-sizing of localized irrigation systems. This work shows free software developed using Visual Basic® language that is able to simulate different block combinations of parcels, taking into consideration the pump parameters of flowrate, pressure, power requirements and efficiency and the main hydraulic network parameters of water speed, pressure and head loss. The software we developed was applied to a trickle irrigation system for citrus growing. The equations used to calculate head loss were Hazen-Williams and Darcy-Weisbach, and users could choose between these two equations depending on their application. The software worked efficiently for making the hydraulic calculations, providing simulations that graphically assisted users in choosing which combination of operation parcels (block combinations) and pump parameters (rotation speed and impeller diameter) for optimal operation of the irrigation system. The program ensured that the pressure along the irrigation network was compatible with the nominal operating pressure of the pipeline and safety valves.
IRRIGA, 2004
CONSUMO DE SOLUÇÕES FERTILIZANTES EM PLANTAS ADULTAS DE LIMA ÁCIDA ‘TAHITI’ SOBRE LIMÃO ‘CRAVO’ N... more CONSUMO DE SOLUÇÕES FERTILIZANTES EM PLANTAS ADULTAS DE LIMA ÁCIDA ‘TAHITI’ SOBRE LIMÃO ‘CRAVO’ NAS CONDIÇÕES DE IRRIGAÇÃO LOCALIZADA Carmello Crisafulli Machado; Ithamar Prada Neto; Rubens Duarte CoelhoDepartamento de Engenharia Rural, Escola Superior de Agricultura “Luiz de Queiroz”, Universidade de São Paulo, Piracicaba, SP, [email protected] 1 RESUMO O trabalho de pesquisa foi realizado em um pomar com dez anos de idade, teve como objetivo medir o consumo de diferentes soluções fertilizantes pelo sistema radicular de porta-enxerto limão ‘Cravo’ sobre lima ácida ‘Tahiti’, pela metodologia do lisímetro poroso. Na projeção da copa de cada uma das plantas foram instalados nove conjuntos lisímetricos, sendo três para cada tratamento a ser implantado, sendo estes: água pura (testemunha) Tratamento 1, solução fertilizante com N, P e K Tratamento 2 e solução fertilizante com N, P, K, Ca, Zn e B Tratamento 3. A inclusão dos elementos Ca, Zn, B, e S na solução de N, P e K (Tratam...
Revista Brasileira de Engenharia Agrícola e Ambiental, 2000
Com o propósito de se avaliar a eficiência de diferentes dosagens de cloro na desobstrução por tr... more Com o propósito de se avaliar a eficiência de diferentes dosagens de cloro na desobstrução por tratamento de choque de gotejadores, conduziu-se um experimento no Laboratório de Irrigação do Departamento de Engenharia Rural da Escola Superior de Agricultura "Luiz de Queiroz"- ESALQ/USP, no qual foram utilizados os seguintes tipos de gotejador Netafim: Streamline 100, Ram 17L, Dripline 2000, Tiran 17 e Typhoon 20, e avaliadas as dosagens de cloro de 150, 300, 450 e 600 mg L-1. A água utilizada no ensaio foi proveniente de fonte hídrica superficial, aproveitada para irrigação. Para os tratamentos de recuperação dos emissores, utilizou-se o hipoclorito de sódio comercial (12%) como fonte de cloro, aplicado continuamente por 60 min, e logo após, deixou-se o produto interagir por 12 h na mangueira, sem fluxo na rede. Para todos os emissores, exceto o Streamline, a aplicação de cloro resultou em aumento da vazão média. Para o modelo Dripline, o tratamento com cloro reduziu a unif...
Horticultura Brasileira, 2008
The modern techniques of water supply through irrigation can substantially reduce water waste, wh... more The modern techniques of water supply through irrigation can substantially reduce water waste, which contributes to attend the enlarging water demand. The objective of this work was to study the influence of subsurface drip irrigation and mulching over melon yield and quality characteristics, in a sandy soil (Typic Hapludox). The experimental design was blocks at random, with four replications. Treatments were displayed in a 2 x 3 factorial (with and without mulching x surface and 0.20 and 0.40 depth subsurface drip irrigation). Mulching using double-sided silver/black film increased fruit average mass, plant production, yield, daily growth rate for plant height and crown diameter, fruit distal diameter, and pulp thickness. The subsurface drip irrigation at 0.20 m depth resulted in larger fruit average mass, plant production, and yield than surface and 0.40 m depth drip irrigation.
Revista Brasileira de Engenharia Agrícola e Ambiental, 2000
Avaliou-se a suscetibilidade de cinco tipos de gotejadores ao processo de entupimento de origem b... more Avaliou-se a suscetibilidade de cinco tipos de gotejadores ao processo de entupimento de origem biológica, testando-se os seguintes modelos da marca comercial Netafim: Streamline 100, Ram 17L, Dripline 2000, Tiran 17 e Typhoon 20; para tanto, utilizou-se delineamento estatístico em blocos ao acaso em parcela subdividida, constituído de cinco tratamentos (modelo de gotejador) na parcela e tempo de funcionamento (9 níveis) na subparcela com quatro repetições. A água utilizada no ensaio provinha de fonte hídrica superficial, utilizada para irrigação, e dela foram isolados diversos gêneros de bactérias, multiplicadas em meio de cultura e utilizadas para manter um nível populacional de bactéria no reservatório da bancada de ensaio superior a 50.000 UFC mL-1, através de inoculações efetuadas quando o número de células decaía a esse patamar. Em intervalos de tempo de funcionamento do sistema de 240 h, a vazão de cada gotejador era medida totalizando um tempo de 2160 h de operação. Os resul...
Engenharia Agrícola, 2012
In this study is presented an economic optimization method to design telescope irrigation lateral... more In this study is presented an economic optimization method to design telescope irrigation laterals (multidiameter) with regular spaced outlets. The proposed analytical hydraulic solution was validated by means of a pipeline composed of three different diameters. The minimum acquisition cost of the telescope pipeline was determined by an ideal arrangement of lengths and respective diameters for each one of the three segments. The mathematical optimization method based on the Lagrange multipliers provides a strategy for finding the maximum or minimum of a function subject to certain constraints. In this case, the objective function describes the acquisition cost of pipes, and the constraints are determined from hydraulic parameters as length of irrigation laterals and total head loss permitted. The developed analytical solution provides the ideal combination of each pipe segment length and respective diameter, resulting in a decreased of the acquisition cost.
Engenharia Agrícola, 2012
This study aimed to evaluate the spatial variability of leaf content of macro and micronutrients.... more This study aimed to evaluate the spatial variability of leaf content of macro and micronutrients. The citrus plants orchard with 5 years of age, planted at regular intervals of 8 x 7 m, was managed under drip irrigation. Leaf samples were collected from each plant to be analyzed in the laboratory. Data were analyzed using the software R, version 2.5.1 Copyright (C) 2007, along with geostatistics package GeoR. All contents of macro and micronutrients studied were adjusted to normal distribution and showed spatial dependence.The best-fit models, based on the likelihood, for the macro and micronutrients were the spherical and matern. It is suggest for the macronutrients nitrogen, phosphorus, potassium, calcium, magnesium and sulfur the minimum distances between samples of 37; 58; 29; 63; 46 and 15 m respectively, while for the micronutrients boron, copper, iron, manganese and zinc, the distances suggests are 29; 9; 113; 35 and 14 m, respectively.
Abstract: Abstract: Abstract: Abstract: The present study attempts to evaluate the pressure incre... more Abstract: Abstract: Abstract: Abstract: The present study attempts to evaluate the pressure increase in the hydraulic network of a micro-irrigation system when partial or total clogging of emitters occurs. The evaluated area was of 280 ha, with citrus irrigation based on subsurface auto-compensating drippers. The methodology utilized a mathematical model based on Bernoulli's equation, simulating the effects of different clogging rates on the network pressure. To evaluate the pressure variation in the system, the obstructions in the range from 0 to 100% were simulated. For the condition of 50% clogging, 80% of the total pipeline length presented hydraulic pressure more than the nominal pressure foreseen in the project. The mathematical model permitted the simulation of: (a) the variation of the motor-speed of the pump (diesel energy), as a possible solution for controlling the excess pressure problem due to clogging (b) the pressure increase in the network with rotation in exces...
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Papers by Rubens Duarte Coelho