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| Canafístula,Francisco José Firmino; Lopes,Fernando Bezerra; Soares,Rogério Barbosa; Andrade,Eunice Maia de; Teixeira,Adunias dos Santos. |
| Utilizar inversores no controle de vazão de sistemas de bombeamento por meio da variação de sua velocidade pode ter uma maior viabilidade, caso o custo de sensores seja minimizado. Este trabalho investiga, por intermédio de análise multivariada, uma variável adequada ao pseudocontrole da vazão de um sistema de irrigação que economize o uso de sensores e simplifique o sistema de controle. Uma bancada de ensaio para coleta dados foi montada no laboratório e os dados foram processados no Statistical Package for the Social Sciences (SPSS). A análise de agrupamento hierárquico utilizando o método de Ward com base na distância euclidiana quadrática mostrou um grupo composto de quatro variáveis, estando presente nesse grupo a vazão, voltas no registro, altura do... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Agricultura de precisão; Instrumentação; Sensores. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782010001100011 |
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| Almeida,Eurileny Lucas de; Teixeira,Adunias dos Santos; Silva Filho,Francisco Chagas da; Assis Júnior,Raimundo Nonato de; Leão,Raimundo Alípio de Oliveira. |
| ABSTRACT High cost and long time required to determine a retention curve by the conventional methods of the Richards Chamber and Haines Funnel limit its use; therefore, alternative methods to facilitate this routine are needed. The filter paper method to determine the soil water retention curve was evaluated and compared to the conventional method. Undisturbed samples were collected from five different soils. Using a Haines Funnel and Richards Chamber, moisture content was obtained for tensions of 2; 4; 6; 8; 10; 33; 100; 300; 700; and 1,500 kPa. In the filter paper test, the soil matric potential was obtained from the filter-paper calibration equation, and the moisture subsequently determined based on the gravimetric difference. The van Genuchten model... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Richards Chamber; Haines Funnel; Whatman No. 42 filter paper. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832015000501344 |
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| Neves,Antonia Leila Rocha; Lacerda,Claudivan Feitosa de; Teixeira,Adunias dos Santos; Costa,Carlos Alexandre Gomes; Gheyi,Hans Raj. |
| Abstract Cowpea crop is of great importance for northeast Brazil. The objective of this work was to evaluate the application of saline water in different developing stages on plant growth and changes in soil characteristics, measured by soil coverage, and on yield of cowpea plants. The experiment was conducted under field conditions, during the dry season in a completely randomized block design with five treatments and five replications. Each experimental unit consisted of 4 lines of plants with 5.0 m long. The treatments evaluated were: 1. irrigation with groundwater with electrical conductivity (ECw) of 0.8 dS m-1 during the whole crop cycle; 2. saline water (5.0 dS m-1) during the whole crop cycle; 3, 4 and 5. saline water (5.0 dS m-1) up to 22nd,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Vigna unguiculata; Image classification; Salinity of the water; Salt tolerance. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1806-66902010000100059 |
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| Almeida,Eurileny Lucas de; Teixeira,Adunias dos Santos; Rocha Neto,Odílio Coimbra da; Leão,Raimundo Alípio de Oliveira; Canafístula,Francisco José Firmino. |
| ABSTRACT Due to the need to monitor soil water tension continuously, the instantaneous profile method is considered laborious, requiring a lot of time, and especially manpower, to set up and maintain. The aim of this work was to evaluate the possibility of using capacitive sensors in place of tensiometers with the instantaneous profile method in an area of the Lower Acaraú Irrigated Perimeter. The experiment was carried out in a Eutrophic Red-Yellow Argisol. The sensors were installed 15, 30, 45 and 60 cm from the surface, and powered by photovoltaic panels, using a power manager to charge the battery and to supply power at night. Records from the capacitive sensors were collected every five minutes and stored on a data acquisition board. With the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Richards equation; Unsaturated water flow; Soil dielectric constant. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1806-66902018000200353 |
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