HYSWASOR — Simulation Model of Hysteretic Water and Solute Transport in the Root Zone

Dirksen, C.; Kool, J. B.; Koorevaar, P.; Genuchten, M. Th. van

doi:10.1007/978-3-642-77947-3_8

Cited by 40 publications

(54 citation statements)

References 26 publications

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“…Dirksen et al (1993) modified Eq. (7), in order to assume that root water uptake decreases when soil matric potentials is lower than a threshold value h * :…”

Section: Modelling Plant Water Stress Responsementioning

confidence: 99%

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Modelling eco-physiological response of table olive trees (Olea europaea L.) to soil water deficit conditions

Rallo

Provenzano

2013

Agricultural Water Management

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a b s t r a c tThe knowledge of crop response to water stress is crucial to predict transpiration reductions under limited soil water conditions and for a rational scheduling of irrigation.In order to assess whatever water stress model, it is necessary to estimate critical thresholds of soil water status, below which plant transpiration starts to decrease.The main objective of the work is to identify the shape and to determine the parameters of table olive orchards (Olea europaea, var. Nocellara del Belice) water stress function, assessed according to relative transpiration or leaf/stem water potential.In order to assess different water stress functions describing the eco-physiological field response to soil water status, an experimental campaign was carried out in a farm located in South-West coast of Sicily. Meteorological data and soil and crop water status were monitored during irrigation seasons 2008 and 2009.A value of soil matric potential of about −40 m was identified as the threshold below which actual transpiration decreases with decreasing soil water content. For values of soil matric potential higher than the critical threshold, actual transpiration resulted almost constant. A similar behavior was observed when the xylematic leaf/stem water potentials were used to quantify the crop water stress. Investigation also showed that the non-linear models better reproduced the initial phase of the transpiration reduction process; for the examined crop, in fact, convex shape models, typical of xerophytes, better reproduce the reductions of actual transpiration under the soil water deficit conditions recognized in the field.

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“…Dirksen et al (1993) modified Eq. (7), in order to assume that root water uptake decreases when soil matric potentials is lower than a threshold value h * :…”

Section: Modelling Plant Water Stress Responsementioning

confidence: 99%

“…Several models have been proposed to quantify the water stress coefficient as linear or nonlinear functions of the soil water status, expressed in terms of matric potential (Feddes et al, 1978;van Genuchten, 1987;Dirksen et al, 1993;Homaee, 1999) or soil water depletion (Steduto et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

Modelling eco-physiological response of table olive trees (Olea europaea L.) to soil water deficit conditions

Rallo

Provenzano

2013

Agricultural Water Management

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“…Steadystate models, which assume steady-state water flow through the soil profile and constant soil solution concentrations at any point of the root zone at all times, are not suitable for irrigated lands under saline conditions (Letey and Feng 2007;Corwin et al 2007;Letey et al 2011). A large number of transient flow and transport models, including UNSATCHEM (Š imůnek et al 1996), SWAP (van Dam et al 1997), HYDRUS-1D (Šimůnek et al 2008), and HYSWASOR (Dirksen et al 1993), among many others, have been developed to simulate integrated effects of climate, soil, and plants.…”

Section: Introductionmentioning

confidence: 99%

Modeling the effects of saline water use in wheat-cultivated lands using the UNSATCHEM model

2012

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Waters of poor quality are often used to irrigate crops in arid and semiarid regions, including the Fars Province of southwest Iran. The UNSATCHEM model was first calibrated and validated using field data that were collected to evaluate the use of saline water for the wheat crop. The calibrated and validated model was then employed to study different aspects of the salinization process and the impact of rainfall. The effects of irrigation water quality on the salinization process were evaluated using model simulations, in which irrigation waters of different salinity were used. The salinization process under different practices of conjunctive water use was also studied using simulations. Different practices were evaluated and ranked on the basis of temporal changes in rootzone salinity, which were compared with respect to the sensitivity of wheat to salinity. This ranking was then verified using published field studies evaluating wheat yield data for different practices of conjunctive water use. Next, the effects of the water application rate on the soil salt balance were studied using the UNSATCHEM simulations. The salt balance was affected by the quantity of applied irrigation water and precipitation/dissolution reactions. The results suggested that the less irrigation water is used, the more salts (calcite and gypsum) precipitate from the soil solution. Finally, the model was used to evaluate how the electrical conductivity of irrigation water affects the wheat production while taking into account annual rainfall and its distribution throughout the year. The maximum salinity of the irrigation water supply, which can be safely used in the long term (33 years) without impairing the wheat production, was determined to be 6 dS m -1 . Rainfall distribution also plays a major role in determining seasonal soil salinity of the root zone. Winter-concentrated rainfall is more effective in reducing salinity than a similar amount of rainfall distributed throughout autumn, winter, and spring seasons.

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“…To compare the root water uptake capacity under various treatment conditions, the actual root water uptake coefficient was divided by a dimensionless reduction function to exclude the effect of water stress [30, 32]: where c rp is the potential root water uptake coefficient (cm 3 cm -1 d -1 ); h is the soil matric potential (cm), transformed with the measured soil water content according to the soil water retention curve [19]; γ ( h ) is the dimensionless reduction function corresponding to water stress, delineated either as linear [30, 33] or non-linear [34, 35]. For simplification, a piecewise linear function [30] was chosen in this study: where h L and h W are threshold values for root water uptake, chosen respectively as -250 and -15000 cm for rice [36–39].…”

Section: Methodsmentioning

confidence: 99%

Characterizing roots and water uptake in a ground cover rice production system

Zuo

Wang

et al. 2017

PLoS ONE

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Background and aimsWater-saving ground cover rice production systems (GCRPS) are gaining popularity in many parts of the world. We aimed to describe the characteristics of root growth, morphology, distribution, and water uptake for a GCRPS.MethodsA traditional paddy rice production system (TPRPS) was compared with GCRPS in greenhouse and field experiments. In the greenhouse, GCRPS where root zone average soil water content was kept near saturation (GCRPSsat), field capacity (GCRPSfwc) and 80% field capacity (GCRPS80%), were evaluated. In a two-year field experiment, GCRPSsat and GCRPS80% were applied.ResultsSimilar results were found in greenhouse and field experiments. Before mid-tillering the upper soil temperature was higher for GCRPS, leading to enhanced root dry weight, length, surface area, specific root length, and smaller diameter of roots but lower water uptake rate per root length compared to TPRPS. In subsequent growth stages, the reduced soil water content under GCRPS caused that the preponderance of root growth under GCRPSsat disappeared in comparison to TPRPS. Under other GCRPS treatments (GCRPSfwc and GCRPS80%), significant limitation on root growth, bigger root diameter and higher water uptake rate per root length were found.ConclusionsDiscrepancies in soil water and temperature between TPRPS and GCRPS caused adjustments to root growth, morphology, distribution and function. Even though drought stress was inevitable after mid-tillering under GCRPS, especially GCRPS80%, similar or even enhanced root water uptake capacity in comparison to TPRPS might promote allocation of photosynthetic products to shoots and increase water productivity.

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HYSWASOR — Simulation Model of Hysteretic Water and Solute Transport in the Root Zone

Cited by 40 publications

References 26 publications

Modelling eco-physiological response of table olive trees (Olea europaea L.) to soil water deficit conditions

Modelling eco-physiological response of table olive trees (Olea europaea L.) to soil water deficit conditions

Modeling the effects of saline water use in wheat-cultivated lands using the UNSATCHEM model

Characterizing roots and water uptake in a ground cover rice production system

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