Vadose zone denitrification enhancement by poplars during dormancy

Ausland, Hayden Willis

doi:10.17077/etd.226r0ssz

Cited by 1 publication

(1 citation statement)

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“…Buffer strips may be studied from a multi-scale perspective (Wiens 1989), ranging from laboratory studies, focusing on processes in controlled settings (e.g., Ausland (2014); Gomes et al (2015)), to watershed or catchment studies (e.g., Smethurst et al 2009;Ratté-Fortin 2014;Uriarte et al 2011;Terrado et al 2014;Dosskey 2001), encompassing or smoothing out local heterogeneities (Wiens 1989;Baker et al 2001) to make real-life assessments or predictions of overall effectiveness (Figure S2a-c; Norris 1993;Verstraeten et al 2006;Smethurst et al 2009;Baker et al 2001). The current study focused on the intermediate scale, sometimes referred to as field scale (Lee et al 2003), plot scale (Gasser et al 2013) or along transects (Munoz-Carpena et al 1999;Osborne and Kovacic 1993).…”

Section: The Influence Of Scale On Agricultural Rbs Hydrologymentioning

confidence: 99%

Hydrological heterogeneity in agricultural riparian buffer strips

Hénault-Éthier

Larocque

Perron

et al. 2017

Journal of Hydrology

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Riparian buffer strips (RBS) may protect surface water and groundwater in agricultural settings, although their effectiveness, observed in field-scale studies, may not extend to a watershed scale. Hydrologically-controlled leaching plots have often shown RBS to be effective at buffering nutrients and pesticides, but uncontrolled field studies have sometimes suggested limited effectiveness. The limited RBS effectiveness may be explained by the spatiotemporal hydrological heterogeneity near non-irrigated fields. This hypothesis was tested in conventional corn and soy fields in the St. Lawrence Lowlands of southern Quebec (Canada), where spring melt brings heavy and rapid runoff, while summer months are hot and dry. One field with a mineral soil (Saint-Rochde-l'Achigan) and another with an organic-rich soil (Boisbriand) were equipped with passive runoff collectors, suction cup lysimeters, and piezometers placed before and after a 3 m-wide RBS, and monitored from 2011 to 2014. Soil topography of the RBS was mapped to a 1 cm vertical precision and a 50 cm sampling grid. On average, surface runoff intersects the RBS perpendicularly, but is subject to substantial local heterogeneity. Groundwater saturates the root zones, but flows little at the time of snowmelt. Groundwater flow is not consistently perpendicular to the RBS, and may reverse, flowing from stream to field under low water flow regimes with stream-aquifer connectivity, thus affecting RBS effectiveness calculations. Groundwater flow direction can be influenced by stratigraphy, local soil hydraulic properties, and historical modification of the agricultural stream beds. Understanding the spatiotemporal heterogeneity of surface and groundwater flows is essential to correctly assess the effectiveness of RBS in intercepting agro-chemical pollution. The implicit assumption that water flows across vegetated RBS, from the field to the stream, should always be verified.

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