Experimental Evidence of Transport of Pesticides through Field Soils—A Review

Abstract

Much information is available in the literature about pesticide transport through soils at the field scale. The purpose of this study is to review the literature with a focus on pesticide leaching to groundwater. The literature was compiled and discussed with respect to different factors that influence pesticide leaching. Pesticide leaching below the root zone has been demonstrated in sandy as well as in loamy soils. Particularly in loamy soils, there is evidence that even strongly adsorbing chemicals can move along preferential flow pathways and that the travel times of pesticides are comparable to those of conservative solutes. The amounts of pesticides leached below the root zone by worst case rainfall events depend on the chemical properties and can reach up to 5% of the applied mass. When there is no heavy rainfall shortly following application of chemicals, the mass annually leached below the root zone is in the range of <0.1 to 1%, occasionally it can reach up to 4%. Although a direct comparison cannot be made, the mass lost by leaching seems generally to be smaller than that lost by runoff, depending of course on the slope of the fields. Several factors that affect pesticide leaching, such as surface preparation, soil structure, soil water content, type of irrigation, pesticide formulation, time of application and rainfall events, are discussed with support of experimental evidence. While some factors showed inconsistent effects, others show promise in controlling leaching mechanisms. These latter factors include initial water content, surface preparation, and time of pesticide application. Based on the reviewed literature, recommendations were made for future research activities.

Impact of Seasonality on Artificial Drainage Discharge under Temperate Climate Conditions

“…This effect is independent of land use and soil texture. The shortened nutrient discharge pathway leads to a reduced denitrification capacity of tile drained landscapes and high values for nutrient or pesticide emission into surface waters (FLURY, 1996;GÄRDENÄS et al, 2006;JARVIS, 2007JARVIS, , 2002MACRAE et al, 2007;TIEMEY-ER et al, 2008, 2009). Measures to reduce this high level of agricultural emissions are often discussed (e.g., KREINS et al, 2010;MANDER et al 2000;SAVCHUK et al, 2008;THIEU et al, 2010).…”

Threshold behaviour in hydrological systems as (human) geo-ecosystems: manifestations, controls, implications

“…Likewise, particle detachment and soil erosion is clearly a threshold process (Hicks et al, 2000;Salles et al, 2000;Hairsine et al, 2002;Shao et al, 2005;Maerker et al, 2008;Scherer, 2008;Ternat et al, 2008), which is controlled by rainfall intensity, shear stress due to overland flow and soil stability. Infiltration, vertical flow and transport of contaminants in field soils may be observed in two qualitatively different modes, namely in preferential pathways or in a slow form in the soil matrix continuum (Bouma, 1981;Beven and Germann, 1982;Edwards et al, 1989;Flury et al, 1994Flury et al, , 1996Stamm et al, 1998;Zehe and Flühler, 2001a, b;Vogel et al, 2005;McGrath et al, 2007). Lateral preferential flow in soil pipe systems, which crucially determines hillslope scale subsurface runoff generation, is intermittent and is likely to be a threshold phenomenon as well (Adams and Parkin, 2002;Buttle and McDonald, 2002;Negishi et al, 2007;Weiler and McDonnell, 2007).…”

“…Today we know of numerous studies that have provided further evidence, demonstrating that that preferential flow in structured soils is indeed the rule rather than the exception (Fig. 3) (Zachmann et al, 1987;Kladivko et al, 1991;Roth et al, 1991;Flury, 1996;Mohanty et al, 1998;Stamm et al, 1998;Stamm et al, 2002). Earthworms are as classical ecosystem engineers of special interest in this context because they build long-lasting soil structures that exert a significant influence on water flows (Edwards et al, 1990b(Edwards et al, , 1992Smettem, 1992;Shipitalo and Butt, 1999) and solute transport (Edwards et al, 1993;Zehe and Flühler, 2001a, b;Domínguez et al, 2004;Alekseeva et al, 2006;Le Bayon and Binet, 2006) but also on organic matter dynamics, pedogenetic processes and plant growth (Lavelle et al, , 2004Hedde et al, 2005;Milcu, 2005;Milcu et al, 2006).…”

Dissipation kinetics and leaching of cyazofamid fungicide in texturally different agricultural soils

“…In soil, it is subjected to adsorption, plant uptake, weather condition, application method, movement and degradation depending on the simultaneous influence of physical, chemical and biological processes. The behavior of pesticides in soil, therefore, depends on the characteristics and overall function of the ecosystem as well as physicochemical properties of active ingredients and of its formulated products (Flury 1996;Kerle et al 2007). In addition to adsorption and biodegradation, it has been recently shown that reduced sulfur species and dissolved organic matter present in soil/sediment are capable of promoting the in situ transformation of otherwise recalcitrant pesticides (Zeng et al 2011(Zeng et al , 2012.…”