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Master's Dissertation
DOI
Document
Author
Full name
Marcos Schiavon Villa Nova
Institute/School/College
Knowledge Area
Date of Defense
Published
Piracicaba, 1991
Supervisor
Title in Portuguese
Avaliação do desempenho do tensiômetro de bolha de ar na medida do potencial matricial da água no solo
Keywords in Portuguese
ÁGUA DO SOLO
DESEMPENHO
TENSIÔMETRO
Abstract in Portuguese
O tensiômetro de leitura direta (TBA) foi desenvolvido para substituir o tensiômetro convencional (TC) em medidas de potencial da água no solo. Para testar a performance do instrumento um experimento .foi conduzido em condições de laboratório. Seis vasos foram preenchidos com cerca de 15 kg de solo arenoso e seis com cerca de 13 kg solo argiloso (solo seco ao ar). No centro dos vasos foram instalados seis tensiômetros de 1eitura direta e seis tensiômetros convencionais. Os vasos com tensiômetros foram saturados, cobertos com plástico e conduzidos a drenar por vários dias, após os quais, o plástico foi retirado iniciando-se um ciclo de secagem do solo. Cada vaso foi pesado diariamente para determinar-se a umidade do solo (e). Os tensiômetros foram lidos duas vezes ao dia (às 9:00hs e 15:00hs). Em função disto foi possível estabelecer-se relações de dependência entre Ψ e e para os dois tensiômetros, para cada tipo de solo. Estudou-se também o efeito da pressão atmosférica e temperatura na resposta dada pelo TBA. Verificou-se que o TBA tem um tempo de resposta mais baixo do que o TC sendo que os resultados obtidos indicaram que o TBA pode substituir o TC sem perda de precisão. As seguintes regressões lineares entre TBA e Te foram determinadas (descritas na dissertação).
Title in English
Evaluation of the simplified direct reading "air pocket" tensiometer for matric water potencial measurements
Abstract in English
The direct reading "air pocket" tensiometer (APT) was developed to substitute the conventional tensiometer (CT) in field measurements of soil water status (matric water potential Ψm). In order to test the performance of such instrument an experiment was conducted under laboratory conditions, where 5 containers were filled with about. 22 kg of a dry sandy soil and other six with abont 13 kg of a dry clayey soil. Each container received either a CT or a APT in the center of the soil volume. The containers were then saturated, covered with plastic and left to drain the excess water for several days. Plastic covers were removed to begin a drying cycle, being each container weighted daily in order to estimate its soil water content (e). The tensiometers were read twice a day (at 9 a.m. and at 4:0 p.m.). Therefore, it was possible to establish the relationship Ψ versus e for both, the CT and the APT for each soil type. It was possible to determine the effect of both, air pressure and temperature, upon the results given by the APT. The APT had a 1ower ti me response than the CT. Therefore, the results obtained here indicate that the DRT can replace the CT without precision loss. The following linear regressions between ΨAPT and ΨCT were found (described in the dissertation).
 
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Publishing Date
2019-08-22
 
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