Spreading slurry in winter

3 November 1999



Spreading slurry in winter

Question

HAVING used a dribble bar/umbilical system to spread slurry on wheat and barley during the winter months, I am wondering if the movement of the soil that occurs, both from the tractor wheels and the drag of the cord, will impair the action of residual herbicides.

If it does (and I have a good idea that it does) what would be a good interval to allow between spraying and spreading?

It does act as a very good fertiliser and as such I would not like to stop spreading, given the way it has cut our fertiliser bill over the years.

Response

Caroline Hayes, independent consultant & member of AICC, working with Farmer Buying Group, North Herts Farmers

Answer

HERBICIDE goes on to a field a bit like icing on to a cake; it will stay in the
top half-inch of the soil surface. Any disturbance of the soil will break up
that layer which will inevitably influence the effectiveness of the herbicide.

After about five weeks, however, it should have done its job and there will be
relatively little damage done.

More damage could be caused by the slurry itself; the increased microbial
activity will speed up the break down of the herbicide. The slurry will also
absorb the herbicide, making it unavailable to the weeds.