Interpreting non-steady state tracer breakthrough experiments in sand and clay soils using a dual-porosity model

Evaluation of MACRO model by short-term water and solute transport simulation in Maury silt loam soil

“…The boundary soil water pressure was constant with depth and plot (Table 3). In similar simulation studies, Saxena et al (1994), Andreu et al (1994), Jarvis and Larsson (1998), Jarvis et al (1999), Larsson and Jarvis (1999a), Armstrong et al (2000), and Roulier and Jarvis (2003b) used the values of -12, -10, -12, -10, -10, -10, and -10 cm (average with depth) for the boundary soil water pressure in long-term studies conducted on a clayey, clayey, clayey, silty clay over clay, clayey, clayey, and clayey soil, respectively, which are pre�y close to our value (-7 cm).…”

“…The saturated hydraulic conductivity varies with depth but constant with plot (Table 3). In long-term studies conducted on a clayey, clayey, clayey, clayey, and repellent sandy soil; Saxena et al (1994), Andreu et al (1994), and Larsson and Jarvis (1999a, b) used the values in the range of 50-200, 2-300, 5-200, 20-200, and 66-100 mm/h for the saturated hydraulic conductivity, respectively. The large variation of saturated hydraulic conductivity in the profiles of the soils might be the result of the wide range of macropore channels throughout the profile in these soils.…”

“…These models have shown promising results for the simulation of flow and transport at the soil column or monolith , Saxena et al 1994), but only a few of these models have been tested or evaluated for field conditions due to the lack of the measured data.…”

“…The MACRO model has been tested or evaluated by several researchers for different types of field soils and durations (Jarvis et al 1991a, b, Andreu et al 1994, Jabro et al 1994, Saxena et al 1994, Jarvis 1995, Villholth and Jensen 1998, Jarvis et al 1999, Larsson and Jarvis 1999a, b, Armstrong et al 2000, Gottesburen et al 2000, Roulier and Jarvis 2003a. In these modelling efforts, the model has been tested or evaluated for the long-term simulation of water flow and/or solute and/or pesticide transport under different types of field soils.…”

Approaches to estimating the transfer of radionuclides to Arctic biota

“…There are many factors of Arctic ecosystems which may influence radionuclide behaviour including short growing seasons, prolonged freezing of soil, and effects of low temperatures on biological rates. The influence of some of these have been documented: redistribution within the soil profile as a result of freezing [15,16]; reduction of soil 14 CO 2 degassing rates as a consequence of freezing [17]; effects of temperature, metabolic rate and dietary intake on radionuclide transfer to animals [18][19][20]; reduced sorption rate in soils at lower temperature [21]; and reduced uptake of Cs by soil invertebrates at low temperatures [22]. If exposure to ionising radiation within Arctic terrestrial ecosystems is to be robustly predicted, such factors must be fully understood and properly incorporated into models.…”