Martin Brown wrote:
Nasty persistent stuff. Keeps seeds from germinating properly for about
6 months, and there are regulations about how much you can apply in a
given year.

I've done a little investigation of Atrazine and Aminotriazole.
Aminotriazole seems to break down in a few weeks, so that's not a
problem. Atrazine, on the other hand, has a much longer half life,
typically about 40-60 days, but this can vary significantly depending
on conditions. Moist soil and sunny conditions seem to increase the
breakdown rate. Non-neutral pH levels also increase the breakdown rate
and I've found contradicting information about whether high or low pH
levels are better (Neutral conditions are bad). The half-life is also
reduced in fertile soil.

Quick test is try growing some cheap mustard and cress seed on it. If it
grows OK without dying off then the soil is good enough.

Thanks for the tip -- I'll give that a try. I'm optimistic that the
very high temperatures over the last week and the very hard ground and
my limited "cleaning" of the area will solve the problem.

Regards,
Jonathan