"David Hill" wrote in message
...
I believe the claim is that it "becomes inactive" not "breaks down" in a
given number of days.

To become inactive, either its chemical composition must have been altered,
in which case it has been "broken down", or it must have become bound so
tightly to one or another soil component as to render it inaccessible to
roots. Which is the correct interpretation?

[Franz Heymann]