Solute Transport Modeling in Overland Flow Applied to Fertigation |
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Authors: | P. García-Navarro E. Playán N. Zapata |
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Affiliation: | 1Associate Members, ASCE 21CPS, Universidad de Zaragoza. ACTUR, 50015 Zaragoza, Spain. E-mail: pigar@posta.unizar.es 32Dept. Genética y Producción Vegetal, Laboratorio de Agronomía y Medio Ambiente CSIC-DGA, EEAD-CSIC, Apdo. 202, 50080 Zaragoza, Spain. E-mail: playan@eead.csic.es 43Dept. of Soils and Irrig., Laboratorio de Agronomía y Medio Ambiente CSIC-DGA, SIA-DGA, Apdo. 727, 50080 Zaragoza, Spain. E-mail: nery@eead.csic.es
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Abstract: | A model of solute transport in overland flow is developed and applied to the simulation of surface fertigation. Water flow is simulated using the depth-averaged, 1D shallow water equations. Solute flow is represented by an advection-diffusion model. The resulting set of three partial differential equations is sequentially solved at each time step. First, water flow is computed using the explicit two-step McCormack method. Based on the obtained velocity field, solute transport is explicitly determined from the advection-diffusion equation using the operator split technique. Four field experiments involving fertigation events on an impervious free-draining border were performed to validate the proposed model and to obtain estimates of Kx, the longitudinal dispersion coefficient. A value of Kx = 0.075 m2 s?1 satisfactorily reproduces the field experiments. The model is also applied to the simulation of a fertigation event on a pervious border. A sensitivity analysis is performed to assess the dependence of fertilizer distribution uniformity on the value of Kx. Finally, the proposed model is compared with a previous model based on pure advection. |
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