A SWACROP-based potato root water-uptake function as determined under tropical conditions

Utset, Angel; Rúiz, María Elena; García, J.; Feddes, R.A.

doi:10.1007/bf02358510

Cited by 23 publications

(18 citation statements)

References 9 publications

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“…In Fig. 2, the measured Trf of potato (Utset et al 2000) and the Trf proposed by Feddes et al (1978) and van Genutchen (1987) were shown for comparison. It should be noted that the Trf proposed by Feddes et al (1978) was obtained by connecting h1 (0 kPa), h2 (5 kPa), h3 (100 kPa) and h4 (1500 kPa).…”

Section: Comparisons With Measured or Assumed Trf In Literaturementioning

confidence: 91%

“…Various numerical studies (Nyambayo and Potts, 2010;Fatahi et al, 2010;Garg et al, 2012) have been conducted to simulate transpiration-induced suction. In general, these studies assumed some empirical Rdf and Trf reported in the literature, even though the plant species studied in each of the numerical studies was/were not the same as those used to derive Trf (Feddes et al, 1978;van Genuchten, 1987;Wesseling 1991;Utset et al, 2000) and Rdf (López et al, 2001). The measurements of Rdf and Trf from the existing studies were mainly derived for crop species such as potato and wheat.…”

Section: Introductionmentioning

confidence: 99%

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Transpiration reduction and root distribution functions for a non-crop species Schefflera heptaphylla

Garg

Leung

2015

CATENA

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Quantifying soil suction induced by plant transpiration is vital for engineers to analyse the performance of geotechnical infrastructure such as landfill covers. Transpiration reduction function (Trf) and root distribution function (Rdf) are the two plant properties that govern rootwater uptake ability. These two functions have been quantified for various crop species, but they are sometimes used to study the behaviour non-crop species, even though they are known to be plant-specific. In this study, specific Trf and Rdf were measured for six replicates of S. heptaphylla that have a range of leaf area index (LAI) from 1.0 to 3.5 in silty sand. S. heptaphylla is a non-crop tree species that has been commonly used for ecological restoration in many subtropical regions. Trf of each replicate was obtained by relating normalised transpiration rate with suction. After testing, the root system of each tree individual was imaged to determine normalised root area index (RAI) profile (i.e., Rdf). Normalised transpiration rate for S. heptaphylla with higher LAI (3 and 3.5) has lower tolerance of water stress as their normalised transpiration rate reduced at much lower suctions, as compared to those with lower LAI (i.e., 1-2.5). It is found that only when suction is lower than 50 kPa, the measured Trf of S. heptaphylla is similar to some of those presumed in the literature. The measurement of Rdf shows that the maximum amount of roots for S. heptaphylla was at depths of 70-80% of the root depth, in contrast to crops species whose root distribution is typically uniform or linearly decreasing.

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Section: Comparisons With Measured or Assumed Trf In Literaturementioning

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Transpiration reduction and root distribution functions for a non-crop species Schefflera heptaphylla

Garg

Leung

2015

CATENA

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“…The actual crop daily evapotranspiration rates are calculated in SWAP by reducing the potential crop evapotranspiration rate (ET c ), according to the simulated root water-uptake and to the maximum soil evaporation flux, which depend on the simulated soil water-contents (Van Dam et al, 1997). SWAP uses the Feddes et al (1978) root water-uptake function, which has been found suitable for simulating a wide rank of soil-water contents (Leenhardt et al, 1995;Utset et al, 2000). Rainfall interception and soil-evaporation restrictions are also considered in SWAP simulations (Van Dam et al, 1997).…”

Section: Methodsmentioning

confidence: 99%

“…Nevertheless, actual data variability is usually higher than simulated results and many uncontrolled factors can lead to smaller differences between actual and simulated data than those predicted by the theoretical sensitivity analyses. Hence, the correspondence between model outputs and actual data could remain even after model-input changes (Clemente et al, 1994;Utset et al, 2000), although those changes should lead to significant differences, according to the sensitivity analyses. Present paper goal is to assess the differences between actual and simulated maize water-use in a Mediterranean landplane, considering the PT and the PM approaches as the reference evapotranspiration inputs in the model simulations.…”

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confidence: 99%

Comparing Penman–Monteith and Priestley–Taylor approaches as reference-evapotranspiration inputs for modeling maize water-use under Mediterranean conditions

Utset

Farré

Martı́nez-Cob³

et al. 2004

Agricultural Water Management

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113

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A comparison between experimental and simulated data, considering the Priestley and Taylor (PT) and Penman-Monteith (PM) Reference-Evapotranspiration (ET) approaches was carried out. Experimental data, obtained from an irrigation assessment, conducted during the 1995 and 1996 maize growth-seasons at Zaragoza, Spain, was compared to the mechanistic-model SWAP simulation-results, considering each of the ET 0 calculation approaches in the model input. Soil hydraulic properties, meteorological data, seeding and harvest dates, crop water management and other experimental data were used as SWAP input. As corresponding to the windy and dry conditions found in many Mediterranean landplanes, PT ET 0 values were significantly lower than PM ET 0 calculations. Furthermore, simulated actual evapotranspirations considering the PT approach (PT-ET c) were lower than those found in the simulations that consider the PM approach (PM-ET c). Correspondingly, simulated drainage flux and soil water contents were higher when the PT ET 0 approach was used. The correlation coefficients between simulated and measured actual maize evapotranspirations and soil water contents were statistically significant, but the same for both ET 0 calculation approaches. Mean and median differences between actual and simulated maize water-use were not statistically different from zero for both considered ET 0 calculation approaches. Experimental data variability was significantly higher than simulated variability. The comparisons among the evaluated irrigation options, made with the experimental water-use data, lead almost to the same conclusions than those achieved from the simulated maize water-use. Considering PM-ET c rather than PT-ET c yields no statistical difference in the modeling-based conclusions. According to the obtained results, the PT approach could be used under Mediterranean conditions for comparative assessments aimed to support irrigation decision-making.

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“…The root-water stress response function γ used here is identical to that reported by Utset et al [16], which can be seen graphically in Figure 2. The value of h 3 for T pot = 0.4 cm/d is interpolated from h 3,a and h 3,b , and we have h 3 = −470.…”

Section: Cm/dmentioning

confidence: 49%

Suction Potential and Water Absorption from Periodic Channels in Different Types of Homogeneous Soils

Solekhudin

Ang

2012

EJBE

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In this paper, problems involving infiltration from periodic identical trapezoidal channels into homogeneous soils with root water uptake are considered. The governing equation of infiltration through soil is transformed to a modified Helmholtz equation using Kirchoff transformation with dimensionless variables. A DRBEM with a predictor-corrector scheme is employed to obtain numerical solutions to the modified Helmholtz equation. The proposed method is used to solve infiltration problems in three different types of soil. Results are shown to be physically meaningful.

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A SWACROP-based potato root water-uptake function as determined under tropical conditions

Cited by 23 publications

References 9 publications

Transpiration reduction and root distribution functions for a non-crop species Schefflera heptaphylla

Transpiration reduction and root distribution functions for a non-crop species Schefflera heptaphylla

Comparing Penman–Monteith and Priestley–Taylor approaches as reference-evapotranspiration inputs for modeling maize water-use under Mediterranean conditions

Suction Potential and Water Absorption from Periodic Channels in Different Types of Homogeneous Soils

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