Field determined variation of the unsaturated hydraulic conductivity functions using simplified analysis of internal drainage experiments

Villagra, M. M.; Michiels, P.; Hartmann, Roger; Bacchi, Osny Oliveira Santos; Reichardt, Klaus

doi:10.1590/s0103-90161994000100018

Cited by 5 publications

(4 citation statements)

References 11 publications

(15 reference statements)

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“…The soil conductivity function, at the reference plane, can be estimated under the following hypothesis [47]: (i) the volumetric water content at soil surface (θ0) was assumed to be equal to θ1; (ii) at the reference plane (z4), the volumetric water content (θ4) was assumed to be equal to θ3. Figure 5 illustrates the schematic layout of the SHYPROM system used in our laboratory experiments.…”

Section: Evaluating the Soil K(θ) Function Through The Instantaneous ...mentioning

confidence: 99%

Development and Application of an IoT-Based System for Soil Water Status Monitoring in a Soil Profile

Comegna,

Hassan,

Coppola

2024

Sensors

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Soil water content (θ), matric potential (h) and hydraulic conductivity (K) are key parameters for hydrological and environmental processes. Several sensors have been developed for measuring soil θ–h–K relationships. The cost of such commercially available sensors may vary over several orders of magnitude. In recent years, some sensors have been designed in the framework of Internet of Things (i.e., IoT) systems to make remote real-time soil data acquisition more straightforward, enabling low-cost field-scale monitoring at high spatio-temporal scales. In this paper, we introduce a new multi-parameter sensor designed for the simultaneous estimation of θ and h at different soil depths and, due to the sensor’s specific layout, the soil hydraulic conductivity function via the instantaneous profile method (IPM). Our findings indicate that a second-order polynomial function is the most suitable model (R2 = 0.99) for capturing the behavior of the capacitive-based sensor in estimating θ in the examined soil, which has a silty-loam texture. The effectiveness of low-cost capacitive sensors, coupled with the IPM method, was confirmed as a viable alternative to time domain reflectometry (TDR) probes. Notably, the layout of the sensor makes the IPM method less labor-intensive to implement. The proposed monitoring system consistently demonstrated robust performance throughout extended periods of data acquisition and is highly suitable for ongoing monitoring of soil water status.

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Section: Evaluating the Soil K(θ) Function Through The Instantaneous ...mentioning

confidence: 99%

Development and Application of an IoT-Based System for Soil Water Status Monitoring in a Soil Profile

Comegna,

Hassan,

Coppola

2024

Sensors

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“…In contrast, the application of irrigation water affects a wide variety of water transfer processes, such as surface runoff, infiltration and water loss below the root zone (Bachmann et al, 2006), whose magnitude depends fundamentally on soil h(θ) and K(θ) relationships, that must therefore be precisely determined in order to quantitatively analyze these processes (Villagra et al, 1994).…”

Section: Introductionmentioning

confidence: 99%

Using splines in the application of the instantaneous profile method for the hydrodynamic characterization of a tropical agricultural Vertisol

Rivera-Hernández¹,

Garruña-Hernández²,

Carrillo-Ávila³

et al. 2022

Revista Brasileira De Ciência Do Solo

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“…Para uma camada de solo homogêneo, cada valor de potencial mátrico se relaciona com um conteúdo de água correspondente e esta relação, conhecida como curva de retenção, é característica de cada solo, pois a distribuição dos raios dos poros varia de solo para solo: a retenção da água no solo depende assim da composição granulométrica e do arranjamento estrutural do solo (HILLEL, 2004 Não existem estudos que tratam da distância entre os pontos de medidas, sendo que os valores utilizados normalmente variam de 0,20 até 0,40 cm (CADIMA et al, 1980;CINTRA et al, 2000;HUTCHINSON;BOND, 2001;VILLAGRA et al, 1994;VOLPE et al, 1988;), sendo que Hillel (2004) φ o potencial mátrico em m de água, H a leitura do tensiômetro feita a partir do nível de mercúrio na cuba, em m de mercúrio, h c a distância vertical do nível de mercúrio na cuba à superfície do solo no momento da leitura, em m de água e Z a profundidade de instalação da cápsula, em m de água.…”

Section: O Movimento Da áGua No Solounclassified

“…Em outras palavras, com o tamanho de cápsulas utilizado, pode-se dizer que a Figura 9), obtendo-se coeficientes de determinação ao redor de 0,98 demonstrando o excelente ajuste dos dados. O mesmo procedimento foi adotado porVillagra et al, (1994) obtendo coeficientes de determinação da mesma ordem de grandeza. O tempo inicial de redistribuição foi considerado 0,1 hora para que os cálculos pudessem ser feitos.…”

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Influência da distância de instalação de tensiômetros no campo para o cálculo do gradiente de potencial total no método do perfil instantâneo

Martins¹

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Influence of the distance of installation of tensiometers to calculate total potential gradient in the field soil hydraulic conductivity determination The soil hydraulic conductivity determination method most used under unsaturated field conditions is the instantaneous profile method. This method is based on the integration of Richards equation in relation to soil depth, during the soil water redistribution process, after the profile has been saturated till the interest depth and the soil surface prevented to water flux. The equation that results from the method requires the knowledge of the total potential gradient at the interest depth during the redistribution depth. The basic hypothesis of this work is that there is an installation correct distance of the tensiometer porous cups to calculate the total potential gradient in the instantaneous profile method that provides less error to the hydraulic conductivity determination. In two very distinct texture soil. A metallical rectangular structure of 4.50 m length, 3.00 m width and 0.60 m depth was installed into the soil profile, leaving 0.20 m of its depth above the soil surface. In the center of the delimited area, 26 mercury tensiometers were installed at each 25 mm along the profile from soil depth of 0.10 m to 0.60 m, to calculate the total potential gradient at the 0.50 m soil depth. The gradient used as reference was that calculated by differentiation of the fitted curve of total potential as a function of the vertical position coordinate for the depth of 0.50 m; the other gradients were calculated by finite differences using the distances of 0.05, 0.10, 0.15 and 0.20 m between installed porous cups. Among these values, only the distance of 0.05 m resulted in gradients different of the reference for both soils. Therefore, the other distances (0.10, 0.15 and 0.20 m) away be recommended to calculated the soil water total potential by finite differences in the instantaneous profile method. Would be concluded that the assumption of unit gradient was not suitable for the data obtained for the sandy soil, underestimating the hydraulic conductivity by up to 75%.

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Field determined variation of the unsaturated hydraulic conductivity functions using simplified analysis of internal drainage experiments

Cited by 5 publications

References 11 publications

Development and Application of an IoT-Based System for Soil Water Status Monitoring in a Soil Profile

Development and Application of an IoT-Based System for Soil Water Status Monitoring in a Soil Profile

Using splines in the application of the instantaneous profile method for the hydrodynamic characterization of a tropical agricultural Vertisol

Influência da distância de instalação de tensiômetros no campo para o cálculo do gradiente de potencial total no método do perfil instantâneo

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