A new modelling approach to simulate preferential flow and transport in water repellent porous media: Parameter sensitivity, and effects on crop growth and solute leaching

A modified version of the popular agrohydrological model SWAP has been used to evaluate modelling of soil water flow and crop growth at field situations in which water repellency causes preferential flow. The parameter sensitivity in such situations has been studied. Three options to model soil water flow within SWAP are described and compared: uniform flow, the classical mobile-immobile concept, and a recent concept accounting for the dynamics of finger development resulting from unstable infiltration. Data collected from a severely water-repellent affected soil located in Australia were used to compare and evaluate the usefulness of the modelling options for the agricultural management of such soils. The study shows that an assumption of uniform flow in a water-repellent soil profile leads to an underestimation of groundwater recharge and an overestimation of plant transpiration and crop production. The new concept of modelling taking finger dynamics into account provides greater flexibility and can more accurately model the observed effects of preferential flow compared with the classical mobile–immobile concept. The parameter analysis indicates that the most important factor defining the presence and extremity of preferential flow is the critical soil water content. Comparison of the modelling results with the Australian field data showed that without the use of a preferential flow module, the effects of the clay amendments to the soil were insufficiently reproduced in the dry matter production results. This means that the physical characteristics of the soil alone are not sufficient to explain the measured increase in production on clay amended soils. However, modelling with the module accounting for finger dynamics indicated that the preferential flow in water repellent soils that had not been treated with clay caused water stress for the crops, which would explain the decrease in production.

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Agricultural hillslope soil heterogeneity challenges: first experimental results from SUPREHILL critical zone observatory

10.5194/ismc2021-44 ◽

2021 ◽

Author(s):

Vedran Krevh ◽

Jasmina Defterdarović ◽

Lana Filipović ◽

Zoran Kovač ◽

Steffen Beck-Broichsitter ◽

...

Keyword(s):

Numerical Modeling ◽

Soil Moisture ◽

Solute Transport ◽

Soil Water ◽

Water Flow ◽

Preferential Flow ◽

Soil Heterogeneity ◽

Local Scale ◽

Soil Water Flow ◽

Critical Zone Observatory

<p>SUPREHILL is a new (2020) and first Croatian critical zone observatory (CZO), focused on local scale agricultural e.g., vineyard hillslope processes. The experimental setup includes an extensive sensor-based network accompanied by weighing lysimeters and instruments for surface and subsurface hydrology measurement. The field measurements are supported by novel laboratory and numerical quantification methods for the determination of water flow and solute transport. This combined approach will allow the research team to accurately determine soil water balance components (soil water flow, preferential flow/transport pathways, surface runoff, evapotranspiration), the temporal origin of water in hillslope hydrology (isotopes), transport of agrochemicals, and to calibrate and validate numerical modeling procedures for describing and predicting soil water flow and solute transport. First results from sensors indicate increased soil moisture on the hilltop, which is supported by precipitation data from rain gauges and weighing lysimeters. The presence of a compacted soil horizon and compacted inter-row parts (due to trafficking) of the vineyard seems to be highly relevant in regulating water dynamics. Wick lysimeters confirm the sensor soil moisture data, while showing a significant difference in its repetitions which suggests a possibility of a preferential flow imposed by local scale soil heterogeneity. Measured values of surface and subsurface runoff suggest a crucial role of these processes in the hillslope hydrology, while slope and structure dynamics additionally influence soil hydraulic properties. We are confident that the CZO will give us new insights in the landscape heterogeneity and substantially increase our understanding regarding preferential flow and nonlinear solute transport, with results directly applicable in agricultural (sloped agricultural soil management) and environmental (soil and water) systems. Challenges remain in characterizing local scale soil heterogeneity, dynamic properties quantification and scaling issues for which we will rely on combining CZO focused measurements and numerical modeling after substantial data is collected.</p>

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Interaction Between Plant Roots and Soil Water Flow in Response to Preferential Flow Paths in Northern China

Land Degradation and Development ◽

10.1002/ldr.2592 ◽

2016 ◽

Vol 28 (2) ◽

pp. 648-663 ◽

Cited By ~ 13

Author(s):

Yinghu Zhang ◽

Jianzhi Niu ◽

Mingxiang Zhang ◽

Zixing Xiao ◽

Weili Zhu

Keyword(s):

Soil Water ◽

Water Flow ◽

Preferential Flow ◽

Northern China ◽

Plant Roots ◽

Flow Paths ◽

Preferential Flow Paths ◽

Soil Water Flow

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Pines influence hydrophysical parameters and water flow in a sandy soil

Biologia ◽

10.2478/s11756-013-0254-7 ◽

2013 ◽

Vol 68 (6) ◽

Cited By ~ 12

Author(s):

Ľubomír Lichner ◽

Jozef Capuliak ◽

Natalia Zhukova ◽

Ladislav Holko ◽

Henryk Czachor ◽

...

Keyword(s):

Hydraulic Conductivity ◽

Forest Soil ◽

Soil Water ◽

Water Flow ◽

Sandy Soil ◽

Preferential Flow ◽

Water Repellency ◽

Water Repellent ◽

Wetting Front ◽

Soil Water Repellency

AbstractPines, used for sand dune stabilization, can influence the hydrophysical parameters and water flow in an aeolian sandy soil considerably, mainly due to soil water repellency. Two sites, separated by distance of about 20 m, formed the basis of our study. A control soil (“Pure sand“) with limited impact of vegetation or organic matter was formed at 50 cm depth beneath a forest glade area. This was compared to a “Forest soil” in a 30-year old Scots pine (Pinus sylvestris) forest. Most of the hydrophysical parameters were substantially different between the two soil surfaces. The forest soil was substantially more water repellent and had two-times the degree of preferential flow compared to pure sand. Water and ethanol sorptivities, hydraulic conductivity, and saturated hydraulic conductivity were 1%, 84%, 2% and 26% those of the pure sand, respectively. The change in soil hydrophysical parameters due to soil water repellency resulted in preferential flow in the forest soil, emerging during a simulated heavy rain following a long hot, dry period. The wetting front established in pure sand exhibited a form typical of that for stable flow. Such a shape of the wetting front can be expected in the forest soil in spring, when soil water repellency is alleviated substantially.

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Simulating preferential soil water flow and tracer transport using the Lagrangian Soil Water and Solute Transport Model

10.5194/hess-2019-132 ◽

2019 ◽

Author(s):

Alexander Sternagel ◽

Ralf Loritz ◽

Wolfgang Wilcke ◽

Erwin Zehe

Keyword(s):

Solute Transport ◽

Soil Water ◽

Water Flow ◽

Field Experiments ◽

Preferential Flow ◽

Sensitivity Analyses ◽

Tracer Transport ◽

Soil Matrix ◽

Soil Water Flow ◽

Water And Solute Transport

Abstract. We propose an alternative model to overcome these weaknesses of the Darcy-Richards approach and to simulate preferential soil water flow and tracer transport in macroporous soils. Our LAST-Model (Lagrangian Soil Water and Solute Transport) relies on a Lagrangian perspective on the movement of water particles carrying a solute mass through the soil matrix and macropores. We advance the model of Zehe and Jackisch (2016) by two main extensions: a) a new routine for solute transport within the soil matrix and b) the implementation of an additional 1-D preferential flow domain which simulates flow and transport in a population of macropores. Infiltration into the matrix and the macropores depends on their moisture state and subsequently macropores are gradually filled. Macropores and matrix interact through diffusive mixing of water and solutes between the two domains which depends on their water content and matric potential at the considered depths. The LAST-Model is then evaluated with sensitivity analyses and tested against tracer field experiments at three different sites. The results show the internal and physical validity of the model and the robustness of our solute transport and the linear mixing approach. Further, the model is able to simulate preferential flow through macropores and to depict well the observed 1-D solute mass profile of a tracer experiment with a high computational efficiency and short simulation times.

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Capillary rise affecting crop yields under different environmental conditions

10.5194/hess-2016-598 ◽

2016 ◽

Author(s):

Joop Kroes ◽

Iwan Supit ◽

Martin Mulder ◽

Jos Van Dam ◽

Paul Van Walsum

Keyword(s):

Soil Water ◽

Water Flow ◽

Crop Yields ◽

Capillary Rise ◽

Water Flux ◽

Flow Regimes ◽

Crop Growth ◽

Groundwater Levels ◽

Soil Water Flow ◽

The Impact

Abstract. This paper describes analyses of different soil water flow regimes on growth and yields of grass, maize and potato crops in the Dutch delta, with a focus on the role of capillary rise. Different flow regimes are characterised by differences in soil composition and structure are derived from a national soil database. Capillary rise and its influence on crop growth and resulting yields is simulated using Swap-Wofost with different boundary conditions. Case studies and model experiments are used to illustrate the impact of capillary rise. This impact is clearly present in situations where a groundwater level is present (85 % of NL) but also in other situations the impact of capillary rise on crop growth and production is considerable. When one compares situations with average groundwater levels with free drainage conditions without capillary rise yield-reductions of grassland, maize and potatoes are respectively 25, 4 and 15 % or respectively about 3.2, 0.5 and 1.6 ton dry Matter per ha. Neglecting capillary rise also has impact on the downward leaching water flux, the groundwater recharge. Impact can be considerable; for grassland and potatoes the reduction is 17 and 46 % or 64 and 34 mm. Modelling of soil water flow should consider capillary rise of soil water which will results in improved yield and downward leaching simulations.

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Impact of capillary rise and recirculation on simulated crop yields

Hydrology and Earth System Sciences ◽

10.5194/hess-22-2937-2018 ◽

2018 ◽

Vol 22 (5) ◽

pp. 2937-2952 ◽

Cited By ~ 4

Author(s):

Joop Kroes ◽

Iwan Supit ◽

Jos van Dam ◽

Paul van Walsum ◽

Martin Mulder

Keyword(s):

Groundwater Recharge ◽

Soil Water ◽

Water Flow ◽

Capillary Rise ◽

Shallow Groundwater ◽

Crop Growth ◽

Upward Flow ◽

Soil Water Flow ◽

The Impact ◽

Percolation Water

Abstract. Upward soil water flow is a vital supply of water to crops. The purpose of this study is to determine if upward flow and recirculated percolation water can be quantified separately, and to determine the contribution of capillary rise and recirculated water to crop yield and groundwater recharge. Therefore, we performed impact analyses of various soil water flow regimes on grass, maize and potato yields in the Dutch delta. Flow regimes are characterized by soil composition and groundwater depth and derived from a national soil database. The intermittent occurrence of upward flow and its influence on crop growth are simulated with the combined SWAP-WOFOST model using various boundary conditions. Case studies and model experiments are used to illustrate the impact of upward flow on yield and crop growth. This impact is clearly present in situations with relatively shallow groundwater levels (85 % of the Netherlands), where capillary rise is a well-known source of upward flow; but also in free-draining situations the impact of upward flow is considerable. In the latter case recirculated percolation water is the flow source. To make this impact explicit we implemented a synthetic modelling option that stops upward flow from reaching the root zone, without inhibiting percolation. Such a hypothetically moisture-stressed situation compared to a natural one in the presence of shallow groundwater shows mean yield reductions for grassland, maize and potatoes of respectively 26, 3 and 14 % or respectively about 3.7, 0.3 and 1.5 t dry matter per hectare. About half of the withheld water behind these yield effects comes from recirculated percolation water as occurs in free-drainage conditions and the other half comes from increased upward capillary rise. Soil water and crop growth modelling should consider both capillary rise from groundwater and recirculation of percolation water as this improves the accuracy of yield simulations. This also improves the accuracy of the simulated groundwater recharge: neglecting these processes causes overestimates of 17 % for grassland and 46 % for potatoes, or 63 and 34 mm yr−1, respectively.

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The principle of ‘maximum energy dissipation’: a novel thermodynamic perspective on rapid water flow in connected soil structures

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2009.0308 ◽

2010 ◽

Vol 365 (1545) ◽

pp. 1377-1386 ◽

Cited By ~ 69

Author(s):

Erwin Zehe ◽

Theresa Blume ◽

Günter Blöschl

Keyword(s):

Free Energy ◽

Energy Dissipation ◽

Soil Water ◽

Water Flow ◽

Preferential Flow ◽

Helmholtz Free Energy ◽

Chemical Potential ◽

Cohesive Soil ◽

Soil Structures ◽

Soil Water Flow

Preferential flow in biological soil structures is of key importance for infiltration and soil water flow at a range of scales. In the present study, we treat soil water flow as a dissipative process in an open non-equilibrium thermodynamic system, to better understand this key process. We define the chemical potential and Helmholtz free energy based on soil physical quantities, parametrize a physically based hydrological model based on field data and simulate the evolution of Helmholtz free energy in a cohesive soil with different populations of worm burrows for a range of rainfall scenarios. The simulations suggest that flow in connected worm burrows allows a more efficient redistribution of water within the soil, which implies a more efficient dissipation of free energy/higher production of entropy. There is additional evidence that the spatial pattern of worm burrow density at the hillslope scale is a major control of energy dissipation. The pattern typically found in the study is more efficient in dissipating energy/producing entropy than other patterns. This is because upslope run-off accumulates and infiltrates via the worm burrows into the dry soil in the lower part of the hillslope, which results in an overall more efficient dissipation of free energy.

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