Denier van der Gon HAC ,
Berg S van den ,
Linden AMA van der
33 p
in Dutch
1991
Toon Nederlands
English Abstract Five Dutch soils (a medium loess, a slightly acidic
sandy soil, a slightly alkaline sandy soil, a slightly acidic loamy peat and
a slightly acidic clay peat) were selected according to their expected
vulnerability to phytotoxicity after repeated paraquat application.
Biological availability of paraquat was determined by bioassays with
lettuce. A reduction of 25% in fresh weight of the sprouts was regarded as
phytotoxic. In three out of five soils phytotoxicity was observed at
paraquat concentrations of less than 100 mg.kg-1. No relation between
phytotoxicity and the cation exchange capacity of the soils was found
although in literature cation exchange is mentioned as the main sorption
mechanism. Clay content appeared more important for sorption than the
organic matter content of the soils. Phytotoxicity was found to be
relatively low in soils having a high CaCO3 content. This phenomenon,
however, can not be explained yet.
