The Adequacy of Pressure Plate Apparatus for Determining Soil Water Retention

2008 ◽  
Vol 72 (1) ◽  
pp. 41-49 ◽  
Author(s):  
H. P. Cresswell ◽  
T. W. Green ◽  
N. J. McKenzie
Irriga ◽  
2008 ◽  
Vol 13 (4) ◽  
pp. 517-524 ◽  
Author(s):  
Maria Hermínia Ferreira Tavares ◽  
José Jeremias da Silva Feliciano ◽  
Carlos Manoel Pedro Vaz

ANÁLISE COMPARATIVA DE MÉTODOS PARA DETERMINAÇÃO DA CURVA DE RETENÇÃO DE ÁGUA EM SOLOS   Maria Hermínia Ferreira Tavares1; José Jeremias da Silva Feliciano1; Carlos Manoel Pedro Vaz21Centro de Ciências Exatas e Tecnológicas, Universidade Estadual do Oeste do Paraná, Cascavel, PR, [email protected] 2Empresa Brasileira de Pesquisa Agropecuária, Embrapa Instrumentação Agropecuária, São Carlos, SP.  1 RESUMO             O tradicional método de obtenção da curva de retenção de água no solo através da Câmara de Pressão de Richards é trabalhoso e demorado. Assim, este trabalho teve como objetivo avaliar o emprego de dois diferentes equipamentos TDR, conjugados a tensiômetros, para obter os valores de umidade volumétrica e respectivos valores de tensão, comparando-os aos resultados fornecidos pelo método tradicional. Para as medidas através dos equipamentos TDR, o solo, classificado como Latossolo Vermelho distroférrico (LVdf), foi seco ao ar e passado através de uma peneira2 mm. Os dados de curva de retenção foram ajustados utilizando-se o programa Origin 6.0 Professional através do modelo sugerido por Van Genuchten. A análise dos dados obtidos, realizada através do índice de desempenho c, mostrou que os 2 equipamentos TDR apresentaram performances similares. UNITERMOS: Câmara de Richards, técnica TDR, tensiometria.  TAVARES, M. H. F.; FELICIANO, J. J. S.; VAZ, C. M. P. COMPARATIVE ANALYSIS OF METHODS TO DETERMINE THE SOIL WATER RETENTION CURVE  2 ABSTRACT The traditional method to obtain the soil water retention curve using Richard’s pressure plate apparatus is laborious and time consuming. Thus, the objective of this work was to evaluate the use of two different TDR equipments, coupled to tensiometers, to obtain soil volumetric water content and respective tension values compared to those from traditional methods. For TDR measurements, a Rhodic Hapludox soil was air-dried and passed through a2 mm mesh sieve. Data of water retention curve were adjusted using the Origin 6.0 Professional software and the Van Genuchten model. The analysis of data based on the performance index revealed that the two TDR equipments had similar performances. KEY WORDS: Richard’s pressure plate apparatus, TDR technique, tensiometry.


Soil Research ◽  
2012 ◽  
Vol 50 (8) ◽  
pp. 708 ◽  
Author(s):  
Ewa A. Czyż ◽  
Anthony R. Dexter

In this paper, plant wilting is re-analysed and re-interpreted on the basis of previously published work. Wilting is considered only in terms of the stress caused by the matric suction of the soil water. Other factors that can induce wilting, such as salinity and plant pathogens, are not considered. It is found that there is confusion around the subject for two main reasons. First, it is usually assumed that the matric suction of the pore water that exists in soil samples when they are removed from pressure plate extractors is equal to the air pressure that was applied. Second (and this is a special case of the first reason), because the soil water content when most plants wilt is very close to that remaining in soil samples on pressure plates operating with an air pressure of 1.5 MPa, it is assumed that plants wilt at a pore water suction of 1.5 MPa. These assumptions are examined here, and it is shown that neither of them is true. Published results are used for the wilting condition. The recently described double-exponential (DE) equation for soil water retention is used for cases where the water is non-equilibrated because of hydraulic cut-off. The non-equilibrated condition is appropriate for plant roots because they, like pressure plate extractors, extract water from soil by immiscible displacement. The DE equation is used to illustrate the conditions under which plant wilting can be either a plant or a soil property. It is shown how this approach can be used to estimate the pore water suction at which plants would wilt because the soil is no longer able to supply water to their roots. It is demonstrated that the commonly used, but often erroneous, value for the wilting-point suction of h = 1.5 MPa is a consequence of the fact that this is the largest value of air pressure used in pressure cell extractors. It is therefore neither a plant nor a soil property, but is an artefact of the experimental procedure. The use of the DE equation for soil water retention shows that we know only that h ≤1.5 MPa, and that h can be as small as 0.2 or 0.3 MPa. Implications for estimation of plant water availability in soils, for plant breeding, and for soil microbial activity are discussed.


1987 ◽  
Vol 67 (2) ◽  
pp. 395-397 ◽  
Author(s):  
D. S. STEVENSON

Soil water contents of a sandy loam and a silt loam soil were measured at −1500, −100, and either −20 or −30 kPa (the finer texture at −30 kPa) on pressure plate equipment, after samples of each soil had been treated with one of three soil conditioners or with water as a control treatment. One of the soil conditioners increased the soil water retention of both soils at all matric potentials while the other two increased soil water retention at −1500 kPa in the silt loam. The implications in terms of water availability to plants are discussed briefly. Key words: Matric potentials, soil water retention, soil conditioners, laboratory


2017 ◽  
Vol 16 (4) ◽  
pp. 869-877
Author(s):  
Vasile Lucian Pavel ◽  
Florian Statescu ◽  
Dorin Cotiu.ca-Zauca ◽  
Gabriela Biali ◽  
Paula Cojocaru

2021 ◽  
pp. 51495
Author(s):  
Ruth M. Barajas‐Ledesma ◽  
Vanessa N. L. Wong ◽  
Karen Little ◽  
Antonio F. Patti ◽  
Gil Garnier

Land ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 195 ◽  
Author(s):  
Mirko Castellini ◽  
Anna Maria Stellacci ◽  
Danilo Sisto ◽  
Massimo Iovino

The multi-height (low, L = 3 cm; intermediate, M = 100 cm; high, H = 200 cm) Beerkan run methodology was applied on both a minimum tilled (MT) (i.e., up to a depth of 30 cm) and a no-tilled (NT) bare loam soil, and the soil water retention curve was estimated by the BEST-steady algorithm. Three indicators of soil physical quality (SPQ), i.e., macroporosity (Pmac), air capacity (AC) and relative field capacity (RFC) were calculated to assess the impact of water pouring height under alternative soil management practices. Results showed that, compared to the reference low run, M and H runs affected both the estimated soil water retention curves and derived SPQ indicators. Generally, M–H runs significantly reduced the mean values of Pmac and AC and increased RFC for both MT and NT soil management practices. According to the guidelines for assessment of SPQ, the M and H runs: (i) worsened Pmac classification of both MT and NT soils; (ii) did not worsen AC classification, regardless of soil management parameters; (iii) worsened RFC classification of only NT soil, as a consequence of insufficient soil aeration. For both soil management techniques, a strong negative correlation was found between the Pmac and AC values and the gravitational potential energy, Ep, of the water used for the infiltration runs. A positive correlation was detected between RFC and Ep. The relationships were plausible from a soil physics point of view. NT soil has proven to be more resilient than MT. This study contributes toward testing simple and robust methods capable of quantifying soil degradation effects, due to intense rainfall events, under different soil management practices in the Mediterranean environment.


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