Viscosity dependent dual‐permeability modeling of liquid manure movement in layered, macroporous, tile drained soil

Abstract

[1] A scarcity of information exists on how physical processes govern the movement of liquid manure, or other viscous fluids, through layered macroporous soils. To elucidate these complex flow and transport phenomena, a viscosity dependent, two-dimensional dual-permeability model that considers macropore anisotropy is employed to simulate field experiments where liquid swine manure (LSM) was applied to silt loam with both a soil crust and plowpan layer present. Using data from the field experiment as a benchmark, the model was used to predict nutrient (NH 4 -N and total P) breakthrough to tile drains; and to assess the influence of reduced permeability crust and plowpan layers, and fluid viscosity, on solute movement within 48 h of LSM application. Results demonstrate the importance of viscosity on flow and transport in macroporous soils. By increasing LSM viscosity, nutrient breakthrough to tile drains can be greatly reduced, and near surface nutrient retention can increase. The presence of a nonmacroporous soil crust layer can also lead to reduced nutrient concentrations in tile discharge by reducing pressure heads in the underlying A-horizon soil matrix, resulting in reduced macropore flow; whereas a low permeability plowpan layer at the base of the A horizon can increase pressure heads in the A-horizon soil matrix and lead to increased macropore flow. Multiple target point parameter sensitivity analysis revealed that relative parameter sensitivity can be a transient characteristic, and that hydraulic properties of the A and B horizon tend to exhibit their greatest influence over the respective early and late time solute breakthrough characteristics.

Bromide and chloride tracer movement in macroporous tile-drained agricultural soil during an annual climatic cycle

“…http://dx.doi.org/10.1016/j.jhydrol.2012.06.041 (Bouma et al, 1982;Shipitalo and Gibbs, 2000;Weiler and Naef, 2003;Rosenbom et al, 2008). Because macropores beneath the top soil layer are predominantly vertical features Shipitalo and Gibbs, 2000;Frey and Rudolph, 2011), even when macropores are hydraulically active, the tile drain 'rapid' capture zone is generally narrow relative to tile spacing (Shipitalo and Gibbs, 2000;Frey et al, 2012b).…”

Reactive Transport of Manure‐Derived Nitrogen in the Vadose Zone: Consideration of Macropore Connectivity to Subsurface Receptors

“…Some of the most important macropores in agricultural soils are worm burrows generated by Lumbricus terrestris (Shipitalo and Butt, 1999), but there are other important macropores that include, but are not limited to, soil desiccation cracks and abandoned root channels (Turpin et al, 2007b; Ulén et al, 2014). The degree and nature of macropore hydraulic connectivity (Allaire et al, 2002; Fox et al, 2012; Petersen et al, 2012; Hruby et al, 2016) also strongly influence water flow and chemical transport and reaction processes, as some are connected directly to subsurface receptors (e.g., groundwater and tile drains) while others are not (Frey and Rudolph, 2011; Frey et al, 2012a). The nature of this connectivity needs to be considered explicitly because the macropores directly connected to tile drains, for instance, may be most important in terms of the rapid movement of land‐surface‐derived contaminants to subsurface water flow systems (e.g., tile drains) (Fleming and Bradshaw, 1992; Fox et al, 2004; Akay and Fox, 2007; Frey et al, 2016).…”

Using AnnAGNPS to Predict the Effects of Tile Drainage Control on Nutrient and Sediment Loads for a River Basin

“…For dissolved P loads from the CTD 600 scenario in relation to UCTD, there were net reductions associated with the CTD in 2007-2008. Overall, simplified approaches and modifications to AnnAGNPS (for the version used in this study) that account for subsurface (including tile) transport and fate of P, for instance, could potentially improve the model's capacity to assess the impact of tile drainage BMPs for flat watersheds/river basin systems heavily dominated by tile drainage. However, this is speculative, and we would note that, for larger, mixed-use watershed/river basin systems where significant generalizations and assumptions have to be made regarding model parameters, the AnnAGNPS approach regarding attached/particulate contaminant fate and transport is parsimonious and pragmatic, especially in light of difficulties, such as predicting particulate P transport in soil water environments at many scales (de Jonge et al, 2004;Frey et al, 2012) and the potential for surface erosion/runoff of attached/ particulate pollutants to overshadow contributions from tile drainage systems. For example, Frey et al (2015) observed that ~1.5 kg ha -1 of total P derived from exposed stream bank sediments could enter adjacent surface water in the SNRB as a result of one 15-min-rainfall-induced sediment erosion event.…”

“…In Ontario, Canada, it is estimated that 1.6 million ha of crop land is tile drained (Sunohara et al, unpublished data, 2014). Tile drains are efficient pathways by which contaminants from agricultural fields can enter the broader surface water environment (Gilliam et al, 1979;Kladivko et al, 1991;Drury et al, 1996;Gentry et al, 1998;Geohring et al, 1999;Baker, 2001;Lapen et al, 2008;Frey et al, 2012). Inputs of agricultural contaminants from field to stream can be substantial in tile-intensive landscapes where tile flow occupies a significant proportion of total stream flow.…”