Measurement systems of soil water matric potential and evaluation of soil moisture under different irrigation depths
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Data
2012-06-01
Autores
Beraldo, José M. G.
Cora, José E. [UNESP]
Fernandes, Edemo João [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Associação Brasileira de Engenharia Agrícola (SBEA)
Resumo
O desenvolvimento de novas metodologias e instrumentos que possibilitem determinar o conteúdo de água no solo é de fundamental importância para a prática de irrigação. O estudo teve por objetivo avaliar a eficiência do tensiômetro de punção e a leitura digital em relação ao tensiômetro de coluna de mercúrio e leitura analógica, na obtenção do potencial mátrico, e comparar os valores da umidade do solo obtidos a partir da tensiometria com a técnica da moderação de nêutrons. Foram aplicadas em quatro parcelas experimentais as lâminas de água (de 238,9; 159,8; 118,2 e 65,0 mm). Três repetições de cada tipo de tensiômetro e o sistema de leitura foram instalados na profundidade de 0,20 m. A partir dos valores do potencial mátrico obtidos pelos tensiômetros e pela curva de retenção de água no solo, foi determinada a umidade do solo, e os dados foram comparados com a técnica da moderação de nêutrons. O potencial mátrico da água no solo, medido pelo tensiômetro de punção de leitura digital, não apresentou diferença em relação aos valores obtidos pelo tensiômetro de mercúrio, em potenciais mátricos maiores que -40 kPa. Com ciclos de umedecimento e secamento do solo, o potencial mátrico obtido pelo tensiômetro de punção com leitura digital foi menor do que os valores obtidos pelo tensiômetro de mercúrio.
The development of new methodologies and tools that enable to determine the water content in soil is of fundamental importance to the practice of irrigation. The objective of this study was to evaluate soil matric potential using mercury tensiometer and puncture digital tensiometer, and to compare the gravimetric soil moisture values obtained by tensiometric system with gravimetric soil moisture obtained by neutron attenuation technique. Four experimental plots were maintained with different soil moisture by irrigation. Three repetitions of each type of tensiometer were installed at 0.20 m depth. Based on the soil matric potential and the soil water retention curve, the corresponding gravimetric soil moisture was determined. The data was then compared to those obtained by neutron attenuation technique. The results showed that both tensiometric methods showed no difference under soil matric potential higher than -40 kPa. However, under drier soil, when the water was replaced by irrigation, the soil matric potential of the puncture digital tensiometer was less than those of the mercury tensiometer.
The development of new methodologies and tools that enable to determine the water content in soil is of fundamental importance to the practice of irrigation. The objective of this study was to evaluate soil matric potential using mercury tensiometer and puncture digital tensiometer, and to compare the gravimetric soil moisture values obtained by tensiometric system with gravimetric soil moisture obtained by neutron attenuation technique. Four experimental plots were maintained with different soil moisture by irrigation. Three repetitions of each type of tensiometer were installed at 0.20 m depth. Based on the soil matric potential and the soil water retention curve, the corresponding gravimetric soil moisture was determined. The data was then compared to those obtained by neutron attenuation technique. The results showed that both tensiometric methods showed no difference under soil matric potential higher than -40 kPa. However, under drier soil, when the water was replaced by irrigation, the soil matric potential of the puncture digital tensiometer was less than those of the mercury tensiometer.
Descrição
Palavras-chave
Tensiometer, digital tensiometer, neutron attenuation technique, Tensiômetro, tensímetro digital, técnica de moderação de nêutrons
Como citar
Engenharia Agrícola. Associação Brasileira de Engenharia Agrícola, v. 32, n. 3, p. 467-478, 2012.