engleski

Glyphosate Mobility Assessment in Vineyard Soils Under Different Agroecological Conditions

In a conventional agriculture extensive use of pesticides is considered necessary to improve crop production but at the same time it can have negative effect on soil and water quality. One of the commonly used chemical in vineyards is glyphosate, a broad-spectrum, post emergence, non-selective herbicide with low mobility in soils due to its strong sorption. However, due to different transport processes present in environment it can still be transported to surface or groundwater resources. The main objective of this study was to evaluate glyphosate mobility at two contrasting vineyards in terms of soil properties and landscape position. Two locations were selected for the field trial: Baštica located on the flat coastal terrain (sandy soil), and Jazbina located on a hillslope terrain characteristic (clay soil). At both field sites, zero tension lysimeters were installed and water balance components monitored throughout the year. Undisturbed soil columns were taken from both sites and used to estimate mobility of pesticides by applying irrigation and a known dosage glyphosate (optimum field quantity) in a controlled environment. Water samples from lysimeters and leachate from soil columns were taken periodically and analyzed for active substances. In addition, soil samples were taken, and initial pesticides concentrations were measured, as well as the soil sorption capacity at each site. First results indicate that the sorption coefficient (Kd) was the main process limiting pesticide mobility in soil. Both soils have high capacity to adsorb glyphosate by the soil particles and organic matter present in the soil surface layer with Jazbina location having larger values as expected due to its higher clay content. It can be concluded that the possible losses of pesticides through surface runoff (e.g. colloidal transport) or by soil water preferential flow pathways are present with respect to different environmental condition at each site.

pesticide fate, agricultural soil, soil and water quality, transport experiments

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