SOIL BEHAVIOR OF METAMITRON IN LABORATORY AND LYSIMETER STUDIES

Citation
C. Vischetti et al., SOIL BEHAVIOR OF METAMITRON IN LABORATORY AND LYSIMETER STUDIES, Agronomie, 17(8), 1997, pp. 367-373
Citations number
11
Journal title
ISSN journal
02495627
Volume
17
Issue
8
Year of publication
1997
Pages
367 - 373
Database
ISI
SICI code
0249-5627(1997)17:8<367:SBOMIL>2.0.ZU;2-S
Abstract
The fate of metamitron, a sugar beet herbicide, in soil was studied in laboratory and in field lysimeters under different water regimes. Lab oratory degradation followed first-order kinetics with half-lives rang ing from 18.8 to 56.3 d with different incubation conditions. Lysimete r dissipation was consistently rapid with half-lives ranging from 4.4 to 8.0 d under the different water regimes. The influence of temperatu re on laboratory degradation was within the range reported for many ot her pesticides, while that of soil moisture was lower than for other p esticides. Adsorption was well described by an L-type isotherm with a 1/n value far from unity in common with most polar herbicides. Metamit ron movement through the lysimeters varied with the different amounts of water supplied. Metamitron reached 60 cm in depth at day 7 after tr eatment and 120 cm in depth at day 14 after treatment in lysimeters th at received normal water amounts and about 10% of pesticide moved belo w 120 cm in lysimeters that received, in addition to the normal water, 151 mm water at day 4 after treatment, which simulates a probable spr ing rain event in northern Italy. The marked movement of the pesticide in these conditions suggests that it is to be considered a potential pollutant in irrigated crops but, the rapid disappearance (DT50 4-8 da ys) of the pesticide in the lysimeters by means other than leaching, p artially reduces this risk. ((C) Inra/Elsevier).