Influence of soil tillage and erosion on the dispersion of glyphosate and aminomethylphosphonic acid in agricultural soils

Abstract

A b s t r a c t. Erosion processes can strongly influence the dissipation of glyphosate and aminomethylphosphonic acid applied with Roundup Max® in agricultural soils; in addition, the soil structure state shortly before erosive precipitations fall can be a key parameter for the distribution of glyphosate and its metabolite. Field rain simulation experiments showed that severe erosion processes immediately after application of Roundup Max® can lead to serious unexpected glyphosate loss even in soils with a high presumed adsorption like the Cambisols, if their structure is unfavourable. In one of the no-tillage-plot of the Cambisol, up to 47% of the applied glyphosate amount was dissipated with surface run-off. Moreover, at the Chernozem site with high erosion risk and lower adsorption potential, glyphosate could be found in collected percolation water transported far outside the 2x2 m experimental plots. Traces of glyphosate were found also outside the treated agricultural fields.K e y w o r d s: glyphosate, aminomethylphosphonic acid, erosion, adsorption, soils

Short-term transport of glyphosate with erosion in Chinese loess soil — A flume experiment

“…Many studies have focused on glyphosate adsorption, degradation, and leaching in environments, but little is known about glyphosate transport associated with soil erosion (Borggaard and Gimsing, 2008;Donald, 2002). Laitinen et al (2009) andTodorovic et al (2014) had experimented (plot observations) under field conditions but only reported glyphosate transport by runoff. Thus, the proposal of the present study was to quantify the transport of glyphosate and AMPA associated with runoff and erosion in Chinese loess soils.…”

“…The free forms of glyphosate and AMPA are thus easily dispersed, especially in wet soils due to preferential flow (Vereecken, 2005), and heavy rains shortly after glyphosate application increase the entry of glyphosate to surface water bodies through transport with runoff and suspended load (Botta et al, 2009;Candela et al, 2010;Gjettermann et al, 2009;Peruzzo et al, 2008;Stone and Wilson, 2006;Vereecken, 2005). Luijendijk et al (2003) reported that up to 24% of the glyphosate sprayed on hard surface soil was transported in runoff to surrounding fields, and Todorovic et al (2014) showed that approximately 47% of applied glyphosate was transported in the runoff associated with erosion and tillage managements (plough or not). The solubility of glyphosate contributes much to its contamination of surface water, but glyphosate and AMPA bound to particles suspended in water is another means of glyphosate and AMPA transport, known as particle-facilitated transport (Rügner et al, 2014;VandeVoort et al, 2013).…”

“…The rate of AMPA degradation is also controversial, half-life time ranging from 35 to 151 days (Bergström et al, 2011;Borggaard and Gimsing, 2008;De Jonge et al, 2000). The fate and quantification of glyphosate thus are required to evaluate their threats and to determine the specifics of glyphosate application and related pesticide management (Todorovic et al, 2014;Zablotowicz et al, 2009).…”

“…As a systemic herbicide, glyphosate is intercepted and taken up by the foliage and then enters plant physiological processes that transport it or its principal metabolic product, aminomethylphosphonic acid (AMPA), to the root system, which releases them into the surrounding soils and waters (Laitinen et al, 2007). Applied to bare soil before or after sowing, glyphosate directly reaches the soil and underlies the highest risk of being transported with soil erosion and runoff (Todorovic et al, 2014). The elimination of the glyphosate in the soil mainly depends on microbial degradation through two pathways, one leading to the intermediate formation of sarcosine and glycine, and the other leading to the formation of AMPA (Rueppel et al, 1977).…”

Distribution of glyphosate and aminomethylphosphonic acid (AMPA) in agricultural topsoils of the European Union

“…Particulate transport via water erosion is an important pathway for glyphosate and AMPA towards surface water bodies (Todorovic et al, 2014;Yang et al, 2015). In fact, after a 60 min rain simulation at a rain intensity of 1 mm min Yang et al (2015) observed that 4-5% of the initially applied glyphosate was lost/transported by runoff in the dissolved phase while 8-11% of the applied glyphosate was transported by the suspended load.…”