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Registros recuperados: 7
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Crop coefficient and water consumption of eggplant in no-tillage system and conventional soil preparation REA
Carvalho,Daniel F. de; Lima,Marcio E. de; Oliveira,Alexsandra D. de; Rocha,Hermes S. da; Guerra,José G. M..
Under organic management in Seropédica-RJ, Brazil, using a weighing lysimeter, the crop coefficients (kc), the maximum evapotranspiration and the productivity of eggplant cultivation under two cropping systems (no tillage with straw plus soil with conventional preparation) were determined. A whole randomized layout with two treatments (no tillage and conventional) and five replicates during 134 days of cultivation were adopted. There were no significant differences in the eggplant cultivation in the two cropping systems, with a maximum commercial productivity obtained from 47.42 Mg ha-1 for the no-tillage system, and 47.91 Mg ha-1 for the conventional tillage. The accumulated ETc was 285.15 and 323.44 mm for the no-tillage and conventional, respectively....
Tipo: Info:eu-repo/semantics/article Palavras-chave: Solanum melongena L.; Weighing lysimeter; Irrigation.
Ano: 2012 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162012000400018
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Evapotranspiration and crop coefficient for potato in organic farming REA
Carvalho,Daniel F. de; Silva,Dione G. da; Rocha,Hermes S. da; Almeida,Wilk S. de; Sousa,Eraldo da S..
The aim of this study was to quantify the water consumption and the crop coefficients (Kc) for the potato (Solanum tuberosum L.), in Seropédica, Rio de Janeiro (RJ), Brazil, under organic management, and to simulate the crop evapotranspiration (ETc) using the Kc obtained in the field and the ones recommended by the Food and Agriculture Organization (FAO). The water consumption was obtained through soil water balance, using TDR probes installed at 0.15m and 0.30m deep. At the different stages of development, the Kc was determined by the ratio of ETc and reference evapotranspiration, obtained by Penman-Monteith FAO 56. The crop coefficients obtained were 0.35, 0.45, 1.29 and 0.63. The accumulated ETc obtained in the field was 109.6 mm, while the ETc...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Solanum tuberosum L.; Time domain reflectometry; Irrigation.
Ano: 2013 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162013000100020
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Characterization of venturi injector using dimensional analysis AGRIAMBI
Sobenko,Luiz R.; Frizzone,José A.; Camargo,Antonio P. de; Saretta,Ezequiel; Rocha,Hermes S. da.
ABSTRACT Venturi injectors are commonly employed for fertigation purposes in agriculture, in which they draw fertilizer from a tank into the irrigation pipeline. The knowledge of the amount of liquid injected by this device is used to ensure an adequate fertigation operation and management. The objectives of this research were (1) to carry out functional tests of Venturi injectors following requirements stated by ISO 15873; and (2) to model the injection rate using dimensional analysis by the Buckingham Pi theorem. Four models of Venturi injectors were submitted to functional tests using clean water as motive and injected fluid. A general model for predicting injection flow rate was proposed and validated. In this model, the injection flow rate depends on...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Buckinghan Pi theorem; Irrigation equipment; Fertigation.
Ano: 2019 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662019000700484
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Coeficientes da equação de Angström-Prescott e sua influência na evapotranspiração de referência em Seropédica, RJ AGRIAMBI
Carvalho,Daniel F. de; Silva,Dione G. da; Souza,Adilson P. de; Gomes,Daniela P.; Rocha,Hermes S. da.
A evapotranspiração de referência (ETo) é dependente da quantidade de energia disponível no ambiente e a radiação solar (Rs) é uma variável importante na sua estimativa. Mediante o exposto, o presente trabalho teve como objetivo determinar os coeficientes "a" e "b" da equação de Angströn-Prescott para Seropédica, RJ, e avaliar seus efeitos na estimativa da Rs e da ETo. Utilizaram-se medidas da radiação solar global e número efetivo de horas de brilho solar da estação Ecologia Agrícola (83741 -INMET) do período de 2000 a 2007. Os coeficientes foram determinados por análise de regressão linear, para todo o período e para períodos mensais e anuais. Utilizando-se os coeficientes calculados e os propostos pela FAO (0,25 e 0,50) estimaram-se Rs e ETo, e se...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Radiação solar; Brilho solar; Estação meteorológica; Penman-Monteith.
Ano: 2011 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662011000800011
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Internal surface roughness of plastic pipes for irrigation AGRIAMBI
Rocha,Hermes S. da; Marques,Patricia A. A.; Camargo,Antonio P. de; Frizzone,José A.; Saretta,Ezequiel.
ABSTRACT Assuming that a roughness meter can be successfully employed to measure the roughness on the internal surface of irrigation pipes, this research had the purpose of defining parameters and procedures required to represent the internal surface roughness of plastic pipes used in irrigation. In 2013, the roughness parameter Ra, traditional for the representation of surface irregularities in most situations, and the parameters Rc, Rq, and Ry were estimated based on 350 samples of polyvinyl chloride (PVC) and low-density polyethylene (LDPE) pipes. Pressure losses were determined from experiments carried out in laboratory. Estimations of pressure loss varied significantly according to the roughness parameters (Ra, Rc, Rq, and Ry) and the corresponding...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Friction factor; Head loss; Roughness meter.
Ano: 2017 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662017000300143
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Local head loss caused in connections used in micro-irrigation systems AGRIAMBI
Bombardelli,Wagner W. Á.; Camargo,Antonio P. de; Frizzone,José A.; Lavanholi,Rogério; Rocha,Hermes S. da.
ABSTRACT Information about local head loss caused by connections employed in micro-irrigation systems is hard to be found in literature. The objective of this research was to experimentally determine the local head losses in connections commonly used in micro-irrigation and propose mathematical models using the theorem of Buckingham. The methodology of tests was based on international standards. The tests were carried out under controlled inlet pressure, at 150 kPa, and five to ten units of each connection model were tested. The curves relating flow and head losses were drawn based on 15 flow conditions, obtained under increase and decrease of flow rate. For each condition, 30 points were collected resulting in a sample size of 900 points in each test. For...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Hydraulics; Dimensional analysis; Buckingham Pi theorem.
Ano: 2019 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662019000700492
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Dripper testing: Application of statistical quality control for measurement system analysis AGRIAMBI
Rocha,Hermes S. da; Marques,Patricia A. A.; Camargo,Antonio P. de; Reis,Douglas L. dos; Silva,Eric A. da; Frizzone,José A..
ABSTRACT Laboratory tests for technical evaluation or irrigation material testing involve the measurement of many variables, as well as monitoring and control of test conditions. This study, carried out in 2016, aimed at using statistical quality control techniques to evaluate results of dripper tests. Exponentially weighted moving average control charts were elaborated, besides capability indices for the measurement of the test pressure and water temperature; and study on repeatability and reproducibility (Gage RR) of flow measurement system using 10 replicates, in three work shifts (morning, afternoon and evening), with 25 emitters. Both the test pressure and water temperature remained stable, with “excellent” performance for the pressure adjustment...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Dripper flow; Statistical process control; Repeatability and repro; Control charts; Stability and capability; For measurement process.
Ano: 2017 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662017000900587
Registros recuperados: 7
Primeira ... 1 ... Última
 

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