Testing and comparison of three unsaturated soil water flow models

• Published in: Agricultural water management 1994, Vol.25 (2), p.135-152
• Main Authors: Clemente, R.S., Jong, R.De, Hayhoe, H.N., Reynolds, W.D., Hares, M.
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; clay soils; contenido de agua en el suelo; Earth sciences; Earth, ocean, space; evaporacion; Evaporation; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; glycine max; gramineas; graminee; grasses; LEACHM; loam soils; modele; modelos; ontario; Physical properties; Physics, chemistry, biochemistry and biology of agricultural and forest soils; sandy soils; Soil science; soil water content; Soils; sol argileux; sol sableux; sol sablolimoneux; suelo arcilloso; suelo arenoso; suelo franco; Surficial geology; SWASIM; SWATRE; teneur en eau du sol; transpiracion; transpiration; Vadose zone; Water and solute dynamics; Water flow
• ISSN: 0378-3774; 1873-2283
• DOI: 10.1016/0378-3774(94)90041-8

The performance of three soil water flow models is compared using field data collected from a structureless sandy loam soil cropped to soybeans (located near Simcoe, Ontario, Canada), and a structured clay soil cropped to grass hay (near Ottawa, Ontario, Canada). Two of the models, Soil Water and Actual Transpiration Rate, Extended (SWATRE) and Leaching Estimation and Chemistry Model (LEACHW), are based on the one-dimensional pressure head form of Richards' equation, and the third, SWASIM, is based on the one-dimensional diffusivity-water content form of Richard's equation. The models are tested and compared on the basis of their ability to predict in situ measured soil water content profiles during the growing season at the two field sites. All three models produce acceptable predictions, as evidenced by an average error within ±0.0404 cm 3·cm −3 and a relative error within ±0.2915. None of the models is consistently more accurate than the others. Discrepancies between the models are attributed primarily to differences in how the models account for soil evaporation and plant transpiration.