Modelling particle mobilization and leaching in macroporous soil

Jarvis, Nicholas; Villholth, Karen G.; Ulén, Barbro

doi:10.1046/j.1365-2389.1999.00269.x

Cited by 108 publications

(79 citation statements)

References 42 publications

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“…By strongly associating with the clay surfaces of WDC, transport of OM into deeper soil layers is also possible (Séquaris et al, 2010). Mechanical and chemical processes in soil are key factors which affect the stability of soil aggregates and thus the release and stability of mobile WDCs such as a combination of hydrodynamic parameters (intensive rain, splash erosion, infiltration water rate) and chemical dispersion conditions (the presence of organic matter, increasing pH, decreasing ionic strength and increasing sodium adsorption ratio (SAR)) (Jarvis et al, 1999;Kjaergaard et al, 2004a, b). It has been shown that shaking soil aggregates in low-ionic strength water simulates erosive dispersion (Séquaris et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Effect of metal oxide on surface area and pore size of water-dispersible colloids from three German silt loam topsoils

et al. 2014

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Abstract:The surface area and pore structure of easily dispersed soil particles < 2 µm in size (water-dispersible colloids, WDCs) are important for carbon sequestration and transport in soil. Two processes are essential for the terrestrial carbon cycling. In this work, we determine the effects of dithionite-citrate-bicarbonate (DCB) extractable metal oxides, and oxalate extractable metal oxides on the specific surface area (SSA) and pore structure of WDCs from silt loam topsoils of three TERENO test sites with a similar clay content (20%) in Germany (arable (Selhausen), grassland (Rollesbroich) and forest (Wuestebach) soils). The N 2 gasadsorption (−196°C), small-angle X-ray scattering (SAXS), dynamic light scattering (DLS) and microelectrophoretic (ME) methods were used and compared. Results show that 1) the SSA of the WDCs from Selhausen, Rollesbroich, and Wuestebach decreased more after DCB treatment (27%, 35%, and 44%) than after oxalate treatment (5%, 14%, and 22%). DCB removed metal oxide nanoparticles from WDCs were found to have diameters (d p ) ranging from 4 nm to 8 nm and the surface loading ratios on the surface of aluminosilicate residues in WDCs were estimated to be 11% to 22% for three soils where the highest value was found in the acidic forest soil. 2) Pore sizes in the mesopore range (2 nm to 50 nm) were analyzed in the WDC fractions. The results were discussed in terms of accessible open pores for the pristine WDCs and WDC samples from which metal oxide nanoparticles and organic carbon (OC) had been removed. The lower average pore radius (R p ) measured by the N 2 gasadsorption method based on the total volume (V t ) to SSA ratio variations in WDCs without metal oxides compared to WDC with metal oxides indicated a contraction of the porous structure of WDCs due to the presence of metal oxide nanoparticles. The pore size distribution (PSD) analysis showed a sensitive contribution of metal oxide nanoparticles in the low range of pore sizes (< 25 nm) of WDCs. In SAXS measurements, higher surface fractal dimensions (D s ) were observed in WDCs before the metal oxides removal, which supports a roughness increase of the interfaces in the presence of nanoparticles. The colloidal characterization of WDCs by the DLS and ME methods shows, at a µm scale, the role of positively charged metal oxide nanoparticles in forming WDCs with a more compact structure by decreasing the particle size (d z ) and the negative zeta potential (ζ).3) The comparison of R p , k, d z and d p results between different soils also indicates the dependence on the clay mineralogy of WDCs so that the heterocoagulation between kaolinite and illite (clay minerals of different aspect ratios) increases the size of soil mesopores (Rollesbroich). In conclusion, the results of this study clearly show that the combination of the N 2 gas-adsorption, SAXS, DLS and ME methods allows the characterization of soil porosity in the nanometer range where metal oxide nanoparticles contribute to a more compact structure of WDC.

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Section: Introductionmentioning

confidence: 99%

Effect of metal oxide on surface area and pore size of water-dispersible colloids from three German silt loam topsoils

et al. 2014

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“…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).…”

Section: Resultsmentioning

confidence: 76%

“…Since the soil structure or inter-aggregate pores below the 15-cm depth was clearly defined, water might readily flow through the macropores. In long-term simulation of water and solute/pesticide transport through the profiles of clayey, sandy, clayey, silt loam, clayey, silty clay over clay, clayey, and clayey soils, Jarvis et al (1991b), Saxena et al (1994), Andreu et al (1994), Jarvis (1995), Jarvis and Larsson (1998), Jarvis et al (1999), and Armstrong et al (2000) used the values of 0.05, 0.01, 0.1, 0.1, 0.1, 0.1, 0.1, and 0.05 mm/h (average with depth) for the boundary hydraulic conductivity, respectively, which are similar to our values (Table 3).…”

Section: Resultsmentioning

confidence: 99%

“…Even though there is no clear cut pattern for the distribution of the pore size distribution index, it seems to increase up to the depth of 15 cm and decrease below the 45 cm. Saxena et al (1994), Andreu et al (1994), Jarvis (1995), Jarvis and Larsson (1998), Jarvis et al (1999), Larsson and Jarvis (1999a, b), and Armstrong et al (2000) used the values of 0.1 and 0.8, 0.04, 0.17, 0.1, 0.05, 0.05, and 0.06 for the pore size distribution index in the micropores in studies conducted on a sandy and clayey, clayey, silt loam, clayey, silty clay over clay, clayey, and clayey soils, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…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.…”

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

Merdun¹

2005

PLANT SOIL ENVIRON

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Modeling preferential flow has been a concern of many academic fields in the past 30 years all over the world and helps to prevent groundwater contamination. A dual-porosity model, MACRO, was evaluated for short-term (less than 2 days) simulation of water flow and non-reactive solute (chloride) transport through the profile of six plots in well-structured Maury silt loam soil. Water flow in micropores is calculated by the Richards' equation while simple gravity flow is assumed in the macropores. Solute transport in the micropores is calculated by the convection-dispersion equation (CDE) while the dispersion and diffusion in the CDE is neglected for the solute transport in the macropores. The applied water and chloride reached the bo�om of the profile during the 2 and 1-hour(s) application periods in studies 2 and 3, respectively. There is a strong indication of macropore flow in this soil. Based on the statistical criteria, the model accurately simulated water flow and solute transport with depth and time in all plots. The mean values of three statistical parameters (coefficient of residual mass, model efficiency, and correlation coefficient) for water and chloride transport were -0.0014, 0.791, 0.903 and 0.0333, 0.923, 0.956, respectively. Preliminary studies showed that the model could not simulate flow and transport well enough with the one-domain flow concept. In the two-domain flow, effective diffusion path-length, boundary hydraulic conductivity, and boundary soil water pressure were the three most important parameters that control flow and transport between the two domains. The effective diffusion path-length represented the structural development with depth in the Maury silt loam soil.

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Streck

2004

Handbuch Der Bodenkunde

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Modelling particle mobilization and leaching in macroporous soil

Cited by 108 publications

References 42 publications

Effect of metal oxide on surface area and pore size of water-dispersible colloids from three German silt loam topsoils

Effect of metal oxide on surface area and pore size of water-dispersible colloids from three German silt loam topsoils

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

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