Describing Soil Hydraulic Properties with Sums of Simple Functions

Ross, P. J.; Smettem, K.R.J.

doi:10.2136/sssaj1993.03615995005700010006x

Cited by 117 publications

(86 citation statements)

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“…Variably saturated water flow through such a porous system is uniform and at local equilibrium, and is often described using the Richards equation. Bimodal or multimodal hydraulic functions (e.g., Othmer et al, 1991;Wilson et al, 1992;Ross and Smettem, 1993;Durner, 1994;Mohanty et al, 1997) are an indirect way of representing soil structure in such a uniform flow approach. A one-domain PNE concept of infiltration (Fig.…”

Section: Conceptual Modelsmentioning

confidence: 99%

“…Parameter fitting of retention and hydraulic conductivity measurements on soil cores (Othmer et al, 1991;Ross and Smettem, 1993;Durner, 1994;Coppola, 2000;Köhne et al, 2002b, Priesack andDurner, 2006) UC θ(h) and K(h) of fractured porous media Upscaling of modelled liquid configurations of cross-sections of partially saturated fractured porous soil or rock (Tuller and Or, 2002;Or and Tuller, 2003) UC Moreover, it was suggested to direct more effort to derive pedotransfer functions accounting for soil structure effects (Merdun and Quisenberry, 2004;Pachepsky et al, 2006). The relation between lateral dispersivity, unsaturated hydraulic conductivity, and soil morphological properties, was studied in tracer experiments carried out in columns and field plots with key Belgian soil types (Vanderborght et al, 2001).…”

Section: Column Experiments and Pedotransfer Functionsmentioning

confidence: 99%

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A review of model applications for structured soils: a) Water flow and tracer transport

Köhne

Šimůnek

2009

Journal of Contaminant Hydrology

291

224

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Section: Conceptual Modelsmentioning

confidence: 99%

Section: Column Experiments and Pedotransfer Functionsmentioning

confidence: 99%

A review of model applications for structured soils: a) Water flow and tracer transport

Köhne

Šimůnek

2009

Journal of Contaminant Hydrology

291

224

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“…The SAT, DUL, and LL were used to construct a moisture characteristic using the approach of Cresswell and Paydar (1996) but modified to utilize the functional form suggested by Ross et al (1991). Hydraulic conductivity was modeled as the sum of two pore spaces (Ross and Smettem, 1993). One pore space was created using the shape of the moisture characteristic (Campbell, 1974) and the requirement that conductivity at DUL was a nominal 0.1 mm/day.…”

Section: Soilmentioning

confidence: 99%

Evaluating and predicting agricultural management effects under tile drainage using modified APSIM

et al. 2007

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An accurate and management sensitive simulation model for tile-drained Midwestern soils is needed to optimize the use of agricultural management practices (e.g., winter cover crops) to reduce nitrate leaching without adversely affecting corn yield. Our objectives were to enhance the Agricultural Production Systems Simulator (APSIM) for tile drainage, test the modified model for several management scenarios, and then predict nitrate leaching with and without winter wheat cover crop. Twelve years of data (1990)(1991)(1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001) from northeast Iowa were used for model testing. Management scenarios included continuous corn and corn-soybean rotations with single or split N applications. For 38 of 44 observations, yearly drain flow was simulated within 50 mm of observed for low drainage (< 100 mm) or within 30% of observed for high drain flow. Corn yield was simulated within 1500 kg/ha for 12 of 24 observations. For 30 of 45 observations yearly nitrate-N loss in tile drains was simulated within 10 kg N/ha for low nitrate-N loss (< 20 kg N/ha) or within 30% of observed for high nitrate-N loss. Several of the poor yield and nitrate-N loss predictions appear related to poor N-uptake simulations. The model accurately predicted greater corn yield under split application kg N/ha) compared to single 110 kg N/ha application and higher drainage and nitrate-N loss under continuous corn compared to corn/soybean rotations. A winter wheat cover crop was predicted to reduce nitrate-N loss 38% (341 vs. 537 kg N/ha with and without cover) under 41-years of corn-soybean rotations and 150 kg N/ha applied to corn. These results suggest that the modified APSIM model is a promising tool to help estimate the relative effect of alternative management practices under fluctuating high water tables. RightsWorks produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted. AbstractAn accurate and management sensitive simulation model for tile-drained Midwestern soils is needed to optimize the use of agricultural management practices (e.g., winter cover crops) to reduce nitrate leaching without adversely affecting corn yield. Our objectives were to enhance the Agricultural Production Systems Simulator (APSIM) for tile drainage, test the modified model for several management scenarios, and then predict nitrate leaching with and without winter wheat cover crop. Twelve years of data (1990)(1991)(1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001) from northeast Iowa were used for model testing. Management scenarios included continuous corn and corn-soybean rotations with single or split N applications. For 38 of 44 observations, yearly drain flow was simulated within 50 mm of observed for low drainage (b 100 mm) or within 30% of observed for high drain flow. Corn yield was simulated within 1500 kg/ha for 12 of 24 observations. For 30 of 45 observations yearly nitrate-N loss in tile ...

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“…A new formulation, close to that of Ross and Smetten (1993) or Durner (1994), is used to model the unsaturated properties of the fissured chalk to consider with greater accuracy the bi-modal distribution of the chalk porosity (matrix porosity and fissure porosity). To account for the variation of effective porosity according to recharge conditions and saturation degree of the chalk, a partitioning algorithm similar to that proposed by Zurmühl and Durner (1996) is used.…”

Section: Hydrodynamic and Hydrodispersive Behaviour Of The Chalk Undementioning

confidence: 99%

Migration of contaminants through the unsaturated zone overlying the Hesbaye chalky aquifer in Belgium: a field investigation

Brouyère

Dassargues

Hallet

2004

Journal of Contaminant Hydrology

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This paper presents the results of a detailed field investigation that was performed for studying groundwater recharge processes and solute downward migration mechanisms prevailing in the unsaturated zone overlying a chalk aquifer in Belgium. Various laboratory measurements were performed on core samples collected during the drilling of boreholes in the experimental site. In the field, experiments consisted of well logging, infiltration tests in the unsaturated zone, pumping tests in the saturated zone and tracer tests in both the saturated and unsaturated zones. Results show that gravitational flows govern groundwater recharge and solute migration mechanisms in the unsaturated zone. In the variably saturated chalk, the migration and retardation of solutes is strongly influenced by recharge conditions. Under intense injection conditions, solutes migrate at high speed along the partially saturated fissures, downward to the saturated zone. At the same time, they are temporarily retarded in the almost immobile water located in the chalk matrix. Under normal recharge conditions, fissures are inactive and solutes migrate slowly through the chalk matrix. Results also show that concentration dynamics in the saturated zone are related to fluctuations of groundwater levels in the aquifer. A conceptual model is proposed to explain the hydrodispersive behaviour of the variably saturated chalk. Finally, the vulnerability of the chalk to contamination issues occurring at the land surface is discussed. D

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Describing Soil Hydraulic Properties with Sums of Simple Functions

Cited by 117 publications

References 0 publications

A review of model applications for structured soils: a) Water flow and tracer transport

A review of model applications for structured soils: a) Water flow and tracer transport

Evaluating and predicting agricultural management effects under tile drainage using modified APSIM

Migration of contaminants through the unsaturated zone overlying the Hesbaye chalky aquifer in Belgium: a field investigation

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