Experimental Investigation of Direct Connectivity between Macropores and Subsurface Drains during Infiltration

Akay, Onur; Fox, Garey A.

doi:10.1061/40856(200)301

Cited by 15 publications

(38 citation statements)

References 14 publications

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“…The three field experiments all pay special attention to pesticide transport in macropores connected directly to drains. The potential of earthworm ( Lumbricus terrestris ) burrows to transmit surface applied tracer directly to tile drains was clearly documented by Shipitalo and Gibbs (2000) and verified by Akay and Fox (2007) Furthermore, soil tillage affecting both hydraulic properties of the soil matrix and macroporosity can affect the proportion of rainfall moving preferentially through the profile (Shipitalo et al, 2000) and the leaching of soil particles to field drains (Petersen et al, 2004). Thus, tillage may affect the leaching pattern and leaching mechanisms of strongly sorbing pesticides.…”

mentioning

confidence: 98%

Particle‐facilitated Pesticide Leaching from Differently Structured Soil Monoliths

et al. 2009

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The leaching of soil particles and surface applied 14C-labeled glyphosate and pendimethalin from intact soil columns (height: 50 cm; diameter: 30 cm) were investigated, and the relative significance of particle-facilitated pesticide transport was quantified. Investigations were performed with a recently plowed (four columns) and an untilled (five columns) sandy loam soil. Leaching was driven by three irrigation events (15 mm h(-1); 2 h each). Samples of the leachate were filtered immediately (within 1.5 minutes) using 20 nm filters, and the 14C-pesticide content was determined for filtered and unfiltered samples. Pesticide leaching was driven by preferential water flow in macropores. For the plowed structure, 68+/-10% of the leached glyphosate (average of 6 events+/-std.) was bound to particles whereas significantly less glyphosate was bound to particles in leachate from minimally disturbed columns (17+/-12%). Thus, the results suggest that soil structure affected the mode of transport of glyphosate. It is likely that glyphosate sorbed strongly when applied on recently plowed soil (Kd=503 L kg(-1) for the soil), and that it could be mobilized and transported independently of soil particles more easily when applied on the minimally disturbed soil covered in part with crop residues (Kd<1 L kg(-1) for straw). Significantly less amounts of soil particles were leached from minimally disturbed (119-247 mg) than from recently plowed (441-731 mg) columns. The significance of particle-facilitated pendimethalin leaching could not be accurately quantified due to disagreement between control measurements based on both 14C-activity and chemical analyses.

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mentioning

confidence: 98%

Particle‐facilitated Pesticide Leaching from Differently Structured Soil Monoliths

et al. 2009

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“…As verified in the field by Shipitalo and Gibbs (2000) and laboratory by Akay and Fox (2006), macropores located within 20‐50 cm of the drain tiles will transmit flow and pesticide directly into the drain line. This is currently being accounted for in the EF modification in that an EF of the water/pesticide reaching the water table is diverted directly into the tile line.…”

Section: Resultsmentioning

confidence: 85%

“…The model was capable of simulating these early peaks when using EF of 2%, similar to the value used at Allen County (Figure 3). The 2% EF is justified based on the field and laboratory observations that macropores located within 20‐50 cm of drain lines are “hydrologically” directly connected (Shipitalo and Gibbs, 2000; Akay and Fox, 2006). This 20‐50 cm area represents approximately 2‐5% of the field.…”

Section: Resultsmentioning

confidence: 99%

Modeling Parent and Metabolite Fate and Transport in Subsurface Drained Fields With Directly Connected Macropores¹

Fox¹,

Sabbagh²,

Malone³

et al. 2007

J American Water Resour Assoc

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Few studies exist that evaluate or apply pesticide transport models based on measured parent and metabolite concentrations in fields with subsurface drainage. Furthermore, recent research suggests pesticide transport through exceedingly efficient direct connections, which occur when macropores are hydrologically connected to subsurface drains, but this connectivity has been simulated at only one field site in Allen County, Indiana. This research evaluates the Root Zone Water Quality Model (RZWQM) in simulating the transport of a parent compound and its metabolite at two subsurface drained field sites. Previous research used one of the field sites to test the original modification of the RZWQM to simulate directly connected macropores for bromide and the parent compound, but not for the metabolite. This research will evaluate RZWQM for parent/metabolite transformation and transport at this first field site, along with evaluating the model at an additional field site to evaluate whether the parameters for direct connectivity are transferable and whether model performance is consistent for the two field sites with unique soil, hydrologic, and environmental conditions. Isoxaflutole, the active ingredient in BALANCE® herbicide, was applied to both fields. Isoxaflutole rapidly degrades into a metabolite (RPA 202248). This research used calibrated RZWQM models for each field based on observed subsurface drain flow and/or edge of field conservative tracer concentrations in subsurface flow. The calibrated models for both field sites required a portion (approximately 2% but this fraction may require calibration) of the available water and chemical in macropore flow to be routed directly into the subsurface drains to simulate peak concentrations in edge of field subsurface drain flow shortly after chemical applications. Confirming the results from the first field site, the existing modification for directly connected macropores continually failed to predict pesticide concentrations on the recession limbs of drainage hydrographs, suggesting that the current strategy only partially accounts for direct connectivity. Thirty‐year distributions of annual mass (drainage) loss of parent and metabolite in terms of percent of isoxaflutole applied suggested annual simulated percent losses of parent and metabolite (3.04 and 1.31%) no greater in drainage than losses in runoff on nondrained fields as reported in the literature.

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“…This question is being addressed with a growing interest in hydrologic connectivity, defined by Stieglitz et al (2003) as "the condition by which disparate regions on the hillslope are linked via subsurface water flow." Hydrologic connectivity has been identified as one of the key controls on subsurface lateral flow generation (Tromp-van Meerveld and McDonnell, 2006b), delivery of water from the hillslope to the stream (Jencso et al, 2009), and nutrient and sediment delivery (Akay and Fox, 2007). Pringle (2003) has emphasized the linkages of this concept to ecological variables, such as the fluxes of matter and energy through the ecosystem.…”

Section: Hydrologic Connectivity and Threshold Behaviormentioning

confidence: 99%

Subsurface Flow Networks at the Hillslope Scale

Graham

Lin

2012

Hydropedology

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Experimental Investigation of Direct Connectivity between Macropores and Subsurface Drains during Infiltration

Cited by 15 publications

References 14 publications

Particle‐facilitated Pesticide Leaching from Differently Structured Soil Monoliths

Particle‐facilitated Pesticide Leaching from Differently Structured Soil Monoliths

Modeling Parent and Metabolite Fate and Transport in Subsurface Drained Fields With Directly Connected Macropores¹

Subsurface Flow Networks at the Hillslope Scale

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Experimental Investigation of Direct Connectivity between Macropores and Subsurface Drains during Infiltration

Cited by 15 publications

References 14 publications

Particle‐facilitated Pesticide Leaching from Differently Structured Soil Monoliths

Particle‐facilitated Pesticide Leaching from Differently Structured Soil Monoliths

Modeling Parent and Metabolite Fate and Transport in Subsurface Drained Fields With Directly Connected Macropores1

Subsurface Flow Networks at the Hillslope Scale

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Modeling Parent and Metabolite Fate and Transport in Subsurface Drained Fields With Directly Connected Macropores¹