Estimation of Width and Depth of the Wetted Soil Volume Under a Surface Emitter, Considering Root Water-Uptake and Evaporation
- 175 Downloads
A cylindrical flow model that describes local infiltration from a surface point source, by incorporating evaporation and water extraction by roots, was used to obtain numerical results that were the base for the development and testing of an empirical method for determining the surface and vertical components of the wetting front. The implementation of the mathematical model took place against two of the twelve USDA soil classes, using three water application rates for each one. The empirical methodology consisted of two simple, time dependent empirical relationships: a power law for the stage of the infiltration, which was applied in both directions and a polynomial for the stage after the end of the irrigation, applied only for the vertical component, to account for percolation losses. The statistical criteria used for the evaluation of the method showed good agreement between the numerical results and the values calculated by the empirical relationships. Based on the limited availability of necessary experimental data for detailed analysis of multidimensional transient infiltration, the introduction of such an empirical model, as a design tool for trickle irrigation systems, may contribute to the selection of the optimum application rate and lateral spacing.
Key wordstrickle irrigation modeling empirical relationships water extraction evaporation wetting front USDA soil classes
Unable to display preview. Download preview PDF.
- Ababou R (1981) Modélisation des transferts hydriques dans un sol en infiltration localisée. Thèse de Docteur Ingénieur, Université de GrenobleGoogle Scholar
- Elmaloglou S, Grigorakis G (1997) Linear and nonlinear models of infiltration from surface line source of trickle irrigation. ICID J 46(2):81–92Google Scholar
- Hoogland JC, Feddes RA, Belmans C (1981) Root water uptake model depending on a soil water pressure head and maximum extraction rate. Acta Hortic 119:123–136Google Scholar
- Jury WA, Gardner WR, Gardner WH (1991) Soil physics. John Wiley, New York, p 328Google Scholar
- Remson I, Hornberger GM, Molz FD (1971) Numerical Methods in Subsurface Hydrology. John Wiley, New York, p 389Google Scholar
- Taghavi SA, Marino MA, Rolston DE (1984) Infiltration from a trickle irrigation source. J Irrig Drain Eng ASCE 110(2):331–341Google Scholar
- van Genuchten MTh (1987) A numerical model for water and solute movement in and below the root zone. Res. Rep. 121, USDA–ARS, U.S. Salinity Lab., Riverside, CAGoogle Scholar
- Warrick AW, Amoozegard-Fard A, Lomen DO (1979) Linearized moisture flow from line source with water extraction. Trans ASAE 22(3):549–553Google Scholar
- Zazueta FS, Clark GA, Smajstrla AG, Carrilo M (1995) A simple equation to estimate soil–water movement from a drip irrigation source. Proceedings of the fifth International Microirrigation Congress April 2–6, Florida, pp 851–856Google Scholar