Glyphosate and glufosinate-ammonium runoff from a corn-growing area in ItalyClaudio Screpanti, Cesare Accinelli, Alberto Vicari and Pietro Catizone
Department of Agro-Environmental Science and Technology, University of Bologna, Viale Fanin 44, 40127 Bologna, Italy
(Accepted 4 May 2005)
Abstract - The main objective of this experiment was to estimate field-scale runoff losses of glyphosate and glufosinate-ammonium under natural rainfall conditions. Investigations were carried out at the Runoff Monitoring Station of the University of Bologna (Italy). Glyphosate and glufosinate-ammonium were applied as pre-emergence herbicides on 350-m2 field plots characterized by a uniform slope of 15%. Field plots were cultivated with corn. The persistence and sorption isotherms of the two herbicides were also determined. During the 3-year experimental period low runoff volumes were observed. More specifically, annual runoff volumes did not exceed 4.7 mm. Glyphosate and glufosinate-ammonium concentrations in collected runoff samples rapidly declined with time. The highest glyphosate and glufosinate-ammonium concentrations were 16 and 24 µg L-1, respectively. These peaks were observed in a runoff event occurring 1 day after herbicide treatment. The total maximum amount of glyphosate and glufosinate-ammonium losses were 0.031 and 0.064°/°° of the applied active ingredients, respectively. On the basis of the obtained results, both glyphosate and glufosinate-ammonium showed low potential to contaminate surface water resources. These results were supported by their estimated short persistence and strong sorption in soil. The half-lives of glyphosate and glufosinate-ammonium were 17.5 and 6.4 days, respectively, and their distribution coefficients (Kd) were 746.6 and 23.4 mL g-1, respectively.
Key words: glyphosate / glufosinate-ammonium / runoff / persistence / sorption
Corresponding author: Cesare Accinelli firstname.lastname@example.org
© INRA, EDP Sciences 2005