Herbicide runoff may represent a threat to surface water. The study, carried out in 2009-2010 at Carmagnola, Italy, aimed to assess the efficacy of buffer strip in reducing runoff of flufenacet and isoxaflutole. Buffer strips of different widths covered by spontaneous weed vegetation were realized at the downstream hedge of six plots (1050 m2; 0.5% slope) cultivated with maize. Four plots (TF plots), have 37.1% sand, 57% silt, 5.9% clay, while two plots (RIVA plots) have 18.6% sand, 63.1% silt, 18.3% clay. In TF plots four different buffer strip widths were tested: 0 m (TF0), 2 m (TF2), 4 m (TF4), and 6 m (TF6). In RIVA plots, two widths were tested: 0 m (RIVA0), 6 m (RIVA6). All plots were treated with flufenacet (240 g/ha) and isoxaflutole (50 g/ha). Runoff waters were collected using automatic samplers. After extraction by SPE, determination of both herbicide was performed by GC-MS, with a quantification limit of 0.05 μg/L. In 2009 the highest concentration of flufenacet were found in RIVA0 (67 μg/L). In TF plots concentrations were not higher than 14.9 μg/L (TF4), without significant differences between plots. The reduced efficacy of buffer strips was due to the poor vegetative cover present at time of the first runoff events. During 2010, the highest concentrations of flufenacet were always detected in runoff waters from unbuffered plots. Isoxaflutole was found only in 2009 at the first runoff event with concentration ranging between 2.7 μg/L (RIVA0) and 5 μg/L (RIVA6). Across the years, flufenacet was detected up to 53 (TF plots) and 60 (RIVA plots) days after treatment in 2009 and up to 115 (TF0) and 153 (RIVA) days after treatment during 2010. Flufenacet has shown a higher risk of water contamination than isoxaflutole, particularly in the soil with higher clay content.
Efficacy of buffer strips in reducing flufenacet and isoxaflutole runoff from two soils cultivated with maize
MILAN, MARCO;VIDOTTO, Francesco;LETEY, MARILISA;DE PALO, FERNANDO;FERRERO, Aldo
2012-01-01
Abstract
Herbicide runoff may represent a threat to surface water. The study, carried out in 2009-2010 at Carmagnola, Italy, aimed to assess the efficacy of buffer strip in reducing runoff of flufenacet and isoxaflutole. Buffer strips of different widths covered by spontaneous weed vegetation were realized at the downstream hedge of six plots (1050 m2; 0.5% slope) cultivated with maize. Four plots (TF plots), have 37.1% sand, 57% silt, 5.9% clay, while two plots (RIVA plots) have 18.6% sand, 63.1% silt, 18.3% clay. In TF plots four different buffer strip widths were tested: 0 m (TF0), 2 m (TF2), 4 m (TF4), and 6 m (TF6). In RIVA plots, two widths were tested: 0 m (RIVA0), 6 m (RIVA6). All plots were treated with flufenacet (240 g/ha) and isoxaflutole (50 g/ha). Runoff waters were collected using automatic samplers. After extraction by SPE, determination of both herbicide was performed by GC-MS, with a quantification limit of 0.05 μg/L. In 2009 the highest concentration of flufenacet were found in RIVA0 (67 μg/L). In TF plots concentrations were not higher than 14.9 μg/L (TF4), without significant differences between plots. The reduced efficacy of buffer strips was due to the poor vegetative cover present at time of the first runoff events. During 2010, the highest concentrations of flufenacet were always detected in runoff waters from unbuffered plots. Isoxaflutole was found only in 2009 at the first runoff event with concentration ranging between 2.7 μg/L (RIVA0) and 5 μg/L (RIVA6). Across the years, flufenacet was detected up to 53 (TF plots) and 60 (RIVA plots) days after treatment in 2009 and up to 115 (TF0) and 153 (RIVA) days after treatment during 2010. Flufenacet has shown a higher risk of water contamination than isoxaflutole, particularly in the soil with higher clay content.
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