Analysis of Water Flux and Solute Transport for a Clay Soil under Different Groundwater Conditions in Southern Italy (original) (raw)
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Journal of Hydrology, 2005
This paper presents an evaluation of the Root Zone Water Quality Model(RZWQM) for assessing the fate of water in the soil-crop environment at the field scale under the particular conditions of a Mediterranean region. The RZWQM model is a onedimensional dual porosity model that allows flow in macropores. It integrates the physical, biological and chemical processes occurring in the root zone, allowing the simulation of a wide spectrum of agricultural management practices. This study involved the evaluation of the soil, hydrologic and crop development sub-models within the RZWQM for two distinct agricultural systems, one consisting of a grain corn planted in a silty loam soil, irrigated by level basins and the other a forage corn planted in a sandy soil, irrigated by sprinklers. Evaluation was performed at two distinct levels. At the first level the model capability to fit the measured data was analyzed (calibration). At the second level the model's capability to extrapolate and predict the system behavior for conditions different than those used when fitting the model was assessed (validation). In a subsequent paper the same type of evaluation is presented for the nitrogen transformation and transport model.
Twenty-five years modeling irrigated and drained soils: State of the art
Agricultural Water Management, 2007
Half of the world food production originates from irrigated and drained soils. Advanced soil water flow simulation models have the potential to contribute to the solution of relatively complex problems in irrigation and drainage science and management, provided that field data are available to calibrate and run them. Besides providing a literature review, this paper emphasizes on calibration and mathematical optimization procedures using GIS and remote sensing techniques. Unfortunately, the required level of expertise of integrated GIS, remote sensing and models make the application of sophisticated tools highly dependent on modeling experts. This is one of the chief reasons that soil water flow models have a low operational focus, especially in less developed countries with irrigation systems where they are most needed. The gap between the supply of various advanced models and the application by the irrigation and drainage community needs to be closed. The likelihood of adoption by a broader model user community will increase if models become more user- and data-friendly (or -tolerant) and heterogeneity-aware. During the next 10 years, simulation model development and application should focus on agricultural water savings, understanding recycling of water in the basin context, increase crop water productivity, bring groundwater-overexploitation to a halt and control the build up of soil salinity.
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CATENA, 1990
wheat and maize models (JONES et al. 1984) begin with maximum photosyn-Process simulation models are needed to thetic potential and progressively reduce make use of static soil survey data to this according to available solar energy predict crop performance. One critical and an index of the sufficiency of water link in this chain, the supply of water by during the growing season. However, the the soil to meet the transpirational de-theoretical basis for predicting sufficiency mand of crops, has been modelled on the of water is weak (DENT & COOK 1987) assumption that water supply is directly and it is difficult to achieve sensitivity. related to soil water potential. Sensitivity is important because reduc-Field testing of this relatively simple tion in potential crop yield depends not model shows a close correlation between only on absolute water stress but the pepredicted and measured supply of wa-riod of growth at which stress occurs. ter over a range of crops and of soils The system of water transport from grouped according to their soil water re-the soil to the atmosphere was described lease characteristics. Use of this soil wa-by VAN DEN HONERT (1948) as a ter potential sub-model in turn, offers Soil-Plant-Atmosphere Continuum. The synoptic models of crop production an system is driven by demand for water improved sensitivity to soil conditions. from the atmosphere and supply is governed by resistance within and between
Agricultural Water Management, 2002
In this paper, we evaluated the WAVE 2.1 and the EURO-ACCESS-II models for predicting crop water consumption, water losses by drainage and volumetric soil water content in a cropped soil under Mediterranean conditions. A detailed dataset was constructed for a furrow-irrigated experimental plot on a homogeneous sandy soil, cropped with maize during the seasons 1992 and 1993. The calibration and the validation results of the models were evaluated by using both simulation graphics and two specific modelling evaluation statistics: the root mean square error (RMSE) and the modelling efficiency. Results showed that both models are able to predict the fate of water in this coarse textured irrigated soil subjected to semi-arid Mediterranean environmental and agronomical conditions. Reasonably good predictions of the seasonal evolution both of the crop evapotranspiration and the water losses by drainage were obtained with both models. Soil moisture was also well predicted by the models when considering total soil moisture storage in the root zone of plants. However, the deviations between the predicted and observed moisture values increased when considering each soil layer separately. Sensitivity analysis showed that the input values of the crop coefficient have a significant influence on predictions made by the WAVE 2.1 model. The value of the hydraulic conductivity close to saturation had a significant influence on the predicted water losses by drainage in the EURO-ACCESS-II model. Our results showed that calibration for the specific environmental conditions of the field sites is required before using any of the two models in a purely prediction model. During this calibration, special attention must be given to the input values of those Agricultural Water Management 56 (2002) 113-129
Modeling water flow in cropped soils: Water uptake by plant roots
Environment International, 1995
The Richards' equation is used as the basic paradigm for water flow in unsaturated soils. An empirical sink term is included to represent the uptake of water by the plant roots. This sink term incorporates a concept termed Evaporation Front which represents the drying upper layers and the subsequent ineffectual roots in this zone during surface evaporation. The Richards' equation is solved numerically by expressing the model in finite-difference form using the Crank-Nicolson method. The resulting water profiles are compared with field data.
Parameter selection and testing the soil water model SOIL
Journal of Hydrology, 1997
The soil water and heat simulation model SOIL was tested for its suitability to study the processes of transport of water in soil. Required parameters, particularly soil hydraulic parameters, were determined by field and laboratory tests for some common soil types and for soils subjected to contrasting treatments of long-term grassland and tilled land under cereal crops. Outputs from simulations were shown to be in reasonable agreement with independently measured field drain outflows and soil water content histories. 0022-1694/97/$17.00 O 1997-Elsevier Science B.V. All rights reserved Pll S0022-1694(96)03229-5
Mathematical Models of Water and Solute Transport in Soil
Journal of Applied Solution Chemistry and Modeling, 2017
Improved understanding of water flow and solute transport through the unsaturated zone is important for the sustainable management of soils. As soils are complex and heterogeneous systems, quantification of the transport processes is difficult. More knowledge on the relationship between solute transport process, soil structure, hydrologic initial and boundary conditions, and observation scale is needed here.Modeling unsaturated flow and transport with mathematical or numerical methods is an important tool for predicting the infiltration and redistribution of soil water and the transport of solutes in the unsaturated zone. Flow and transport models are commonly used to support the decision making process in agricultural management, environmental impact assessment, toxic waste control, remediation design, and subsurface cleanup monitoring. The movement of contaminants through porou media describs by the combination of advection, diffusion-dispersion and chemical retardation. The most common model that describes solute transport by convection and dispersion is the convection-dispersion equation (CDE). This equation describes the change in concentration at any point along the flow path as a function of time. This paper is mainly dedicated to a discussion of basic processes for modelling of water flow and contaminant transport in saturated and unsaturated soils. After a brief description of the classical approach for simulating water flow and solute transport in porous media, issues related to water and solute trasport equation in soil.