Fungicides transport in runoff from vineyard plot and catchment: contribution of non-target areas

Abstract

Surface runoff and erosion during the course of rainfall events are major processes of pesticides transport from agricultural land to aquatic ecosystem. These processes are generally evaluated either at the plot or the catchment scale. Here, we compared at both scales the transport and partitioning in runoff water of two widely used fungicides, i.e., kresoxim-methyl (KM) and cyazofamid (CY). The objective was to evaluate the relationship between fungicides runoff from the plot and from the vineyard catchment. The results show that seasonal exports for KM and CY at the catchment were larger than those obtained at the plot. This underlines that non-target areas within the catchment largely contribute to the overall load of runoff-associated fungicides. Estimations show that 85 and 62 % of the loads observed for KM and CY at the catchment outlet cannot be explained by the vineyard plots. However, the partitioning of KM and CY between three fractions, i.e., the suspended solids (>0.7 μm) and two dissolved fractions (i.e., between 0.22 and 0.7 µm and <0.22 µm) in runoff water was similar at both scales. KM was predominantly detected below 0.22 μm, whereas CY was mainly detected in the fraction between 0.22 and 0.7 μm. Although KM and CY have similar physicochemical properties and are expected to behave similarly, our results show that their partitioning between two fractions of the dissolved phase differs largely. It is concluded that combined observations of pesticide runoff at both the catchment and the plot scales enable to evaluate the sources areas of pesticide off-site transport.

Fungicides: An Overlooked Pesticide Class?

“…Furthermore, similar to herbicides and insecticides, fungicide occurrence depends on stream hydrology and several studies report the highest fungicide concentrations during storm events where concentrations might exceed base flow concentrations by a factor of 10. 49 , 50 , 52 …”

Copper in soil fractions and runoff in a vineyard catchment: Insights from copper stable isotopes

“…The road network mainly contributes to the discharge during low rainfall intensity (i.e. N 6 mm h −1 ) (Lefrancq et al, 2014), while the vineyard plots contribute when the rainfall intensity overcomes the saturated hydraulic conductivity (i.e. 58 mm h −1 ± 50, n = 48) (Tournebize et al, 2012).…”

“…The saturated hydraulic conductivity can be reduced by one order of magnitude on plots when top soil sealing appears. Overland flow on plots is reduced by grass strips of 2 to 3 m width at the plot edges (Lefrancq et al, 2014). Hortonian overland flow prevails, as indicated by fast hydrological response to rainfall events (i.e.…”

Do rainfall characteristics affect the export of copper, zinc and synthetic pesticides in surface runoff from headwater catchments?

“…Fungicides, which include various forms of copper (Cu) and synthetic molecules, and herbicides are massively used in vineyards several times across the growing season (Komárek et al, 2010). Exports of up to 1% of the yearly-applied fungicide and herbicide amount on vineyard catchments have been observed previously, although export in surface runoff varies across the seasons and years (Louchart et al, 2001;Dousset et al, 2007;Lefrancq et al, 2014;Babcsányi et al, 2016). The dose and timing of application as well as pesticide sorption and degradation in soil mainly determine pesticide export during rainfall-runoff events (Chen et al, 2018;Parajulee et al, 2018).…”