Soil-moisture limits on plant uptake: An upscaled relationship for water-limited ecosystems

Guswa, Andrew J.

doi:10.1016/j.advwatres.2004.08.016

Cited by 57 publications

(52 citation statements)

References 34 publications

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“…Although numerous publications referred to Ohm's law for describing soil-plant-atmosphere water flows (Gardner and Ehlig, 1963;Feddes and Rijtema, 1972;Landsberg and Fowkes, 1978;Lhomme, 1998;Guswa, 2005), how to define an "equivalent soil water potential" when the soil water potential varies within the root zone was still a pending question.…”

Section: The Soil Equivalent Water Potential Sensed By Plantsmentioning

confidence: 99%

A simple three-dimensional macroscopic root water uptake model based on the hydraulic architecture approach

Couvreur

Vanderborght

Javaux

2012

Hydrol. Earth Syst. Sci.

185

223

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Abstract. Many hydrological models including root water uptake (RWU) do not consider the dimension of root system hydraulic architecture (HA) because explicitly solving water flow in such a complex system is too time consuming. However, they might lack process understanding when basing RWU and plant water stress predictions on functions of variables such as the root length density distribution. On the basis of analytical solutions of water flow in a simple HA, we developed an "implicit" model of the root system HA for simulation of RWU distribution (sink term of Richards' equation) and plant water stress in three-dimensional soil water flow models. The new model has three macroscopic parameters defined at the soil element scale, or at the plant scale, rather than for each segment of the root system architecture: the standard sink fraction distribution SSF , the root system equivalent conductance K rs and the compensatory RWU conductance K comp . It clearly decouples the process of water stress from compensatory RWU, and its structure is appropriate for hydraulic lift simulation. As compared to a model explicitly solving water flow in a realistic maize root system HA, the implicit model showed to be accurate for predicting RWU distribution and plant collar water potential, with one single set of parameters, in dissimilar water dynamics scenarios. For these scenarios, the computing time of the implicit model was a factor 28 to 214 shorter than that of the explicit one. We also provide a new expression for the effective soil water potential sensed by plants in soils with a heterogeneous water potential distribution, which emerged from the implicit model equations. With the proposed implicit model of the root system HA, new concepts are brought which open avenues towards simple and mechanistic RWU models and water stress functions operational for field scale water dynamics simulation.

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Section: The Soil Equivalent Water Potential Sensed By Plantsmentioning

confidence: 99%

A simple three-dimensional macroscopic root water uptake model based on the hydraulic architecture approach

Couvreur

Vanderborght

Javaux

2012

Hydrol. Earth Syst. Sci.

185

223

View full text Add to dashboard Cite

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“…On the other hand, many studies based on the simplified root-soil-water system have not provided a knowledge foundation that is sufficient for our understanding on the complex process of root water uptake. This is why to date a satisfactory description has not yet been made on the practical importance of root distribution that is actually subjected to specific soil water regimes along soil profiles and to the feedback effect of the water uptake on redistribution of soil water under a certain climate condition (Molz 1971;Francis and Pidgeon 1982;Coelho and Or 1999;Guswa 2005). The main obstacle for a thorough understanding and realistic modeling is that few field experimental data have so far been available for examining the effects of root distribution and pattern on both root water uptake and the associated soil water status, particularly when rooting barriers exist in subsoil.…”

Section: Introductionmentioning

confidence: 99%

Root water uptake and profile soil water as affected by vertical root distribution

et al. 2006

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Water uptake by plant roots is a main process controlling water balance in field profiles and vital for agro-ecosystem management. Based on the sap flow measurements for maize plants (Zea mays L.) in a field under natural wet-and dry-soil conditions, we studied the effect of vertical root distribution on root water uptake and the resulted changes of profile soil water. The observations indicate that depth of the most densely rooted soil layer was more important than the maximum rooting depth for increasing the ability of plants to cope with the shortage of water. Occurrence of the most densely rooted layer at or below 30-cm soil depth was very conducive to maintaining plant water supply under the drysoil conditions. In the soil layers colonized most densely by roots, daytime effective soil water saturation (S e ) always dropped dramatically due to the high-efficient local water depletion. Restriction of the rooting depth markedly increased the difference of S e between the individual soil layers particularly under the dry-soil conditions due likely to the physical non-equilibrium of water flow between the layers. This study highlights the importance of root distribution and pattern in regulating soil water use and thereby improving endurance of plants to seasonal droughts for sustainable agricultural productivity.

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“…soil bucket, this type of model has been found to perform well under many conditions: wet soils, when precipitation events tend to be large relative to the bucket depth, and under strong root compensation or hydraulic redistribution of soil moisture (Guswa et al, 2002;Guswa, 2005). Even when the aforementioned conditions do not hold, distortions stemming from the use of the single-layer bucket model are comparable to those coming from other aspects of SEDGES hydrology.…”

Section: Evaluation Of Evapotranspiration and Runoffmentioning

confidence: 73%

Description and validation of the Simple, Efficient, Dynamic, Global, Ecological Simulator (SEDGES v.1.0)

Paiewonsky

Timm

2018

Geosci. Model Dev.

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Abstract. In this paper, we present a simple dynamic global vegetation model whose primary intended use is auxiliary to the land-atmosphere coupling scheme of a climate model, particularly one of intermediate complexity. The model simulates and provides important ecological-only variables but also some hydrological and surface energy variables that are typically either simulated by land surface schemes or else used as boundary data input for these schemes. The model formulations and their derivations are presented here, in detail. The model includes some realistic and useful features for its level of complexity, including a photosynthetic dependency on light, full coupling of photosynthesis and transpiration through an interactive canopy resistance, and a soil organic carbon dependence for bare-soil albedo. We evaluate the model's performance by running it as part of a simple land surface scheme that is driven by reanalysis data. The evaluation against observational data includes net primary productivity, leaf area index, surface albedo, and diagnosed variables relevant for the closure of the hydrological cycle. In this setup, we find that the model gives an adequate to good simulation of basic large-scale ecological and hydrological variables. Of the variables analyzed in this paper, gross primary productivity is particularly well simulated. The results also reveal the current limitations of the model. The most significant deficiency is the excessive simulation of evapotranspiration in mid-to high northern latitudes during their winter to spring transition. The model has a relative advantage in situations that require some combination of computational efficiency, model transparency and tractability, and the simulation of the large-scale vegetation and land surface characteristics under non-present-day conditions.

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Soil-moisture limits on plant uptake: An upscaled relationship for water-limited ecosystems

Cited by 57 publications

References 34 publications

A simple three-dimensional macroscopic root water uptake model based on the hydraulic architecture approach

A simple three-dimensional macroscopic root water uptake model based on the hydraulic architecture approach

Root water uptake and profile soil water as affected by vertical root distribution

Description and validation of the Simple, Efficient, Dynamic, Global, Ecological Simulator (SEDGES v.1.0)

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