road verges on rural roads - NERC Open Research Archive ...

in Lincoln - Lindsey, East and West Suffolk they are not used on <strong>road</strong> edges or
kerbs. In Northamptonshire they are used on kerbed edges only. In Essex they
are extensively used in drainage channels.
The following basic chemicals are used (conanon names according to BS 1831
and supplements) (technical details based on Fryer and Makepeace, 1972). They
may be applied either as sprays, or as dry granules, or as pellets-
(a) Root absorbed residual herbicides
Atrazine )
) Total herbicides, giving a season or more persistence
Simazine
Borate
Bromacil
)
)
Total herbicides, single season persistence only
Dichlobenil )
Total herbicides, single season persistence only
Chlorthiamid )
Monuron )
) Total herbicides, giving a season or more persistence
Diuron
(b) Foliage and root absorbed herbicides
Sodium chlorate (+ fire depressants) Total herbicide with 3 months to
a seasons persistence
Picloram Affecting mainly b<strong>road</strong>-leaved species, persistent for
more than one season
(c) Foliage absorbed herbicides
Aminotriazole B<strong>road</strong> spectrum herbicide, persistence of one to two
months
Paraquat Total herbicide. Non persistent
Dalapon Affects narrow leaved species (e.g. grasses), persistence
of three to four months
2,k-D;MCPA Affect b<strong>road</strong> leaved species (flowering herbs & woody plants),
2,4,5-T ) persistence of a few weeks to six months
Some of these compounds are used in cotmnercially formulated mixtures to take
advantage of different characteristics of compounds in the three groups. A popular
mixture is a combination of monuron/2,4-D/sodium chlorate, and another widely used
mixture is comprised of diuron/dalapon/MCPA. Several mixtures contain either
atrazine or simazine as one of the components and both of these compounds are quite
widely used on their own; diuron is also quite widely used alone, but not monuron.
Neither aminotriazole nor picloram are applied alone in highway situations.
Chlorthiamid and, less frequently, dichlobenil are used specifically for weed
control in hedge bottoms during establishment. The most commonly used compound,
either alone or in combination, is sodium chlorate, which has also been available
the longest.
It appeared from the survey that the choice of chemical to use was not critical
in most counties, and in many instances was decided on grounds of cost alone,
without regard to effectiveness or persistence. Likewise contracts were often