Thursday, 3 July 2008


An exceedingly handsome RHS mole has provided me with the following helpful links about the contaminated farmyard manure problem. Several points arise:

  • The same problem could happen anywhere in the UK because it wasn't just one batch of manure that was contaminated. It's the particular weedkiller implicated that is the problem: in this case, aminopyralid. 
  • Look out for the tell-tale funny twisty foliage as seen on the RHS site. 
  • Why is this happening? Well, aminopyralid binds to the lignin in the grass leaves (despite not affecting them). When the grass is chewed by the cow, the weedkiller isn't released from this binding. In fact, aminopyralid is not even completely broken down when the grass starts to rot in compost either. Evidently it's still being gradually released by the rotting grass when the manure is spread on gardens. This is the problem. 
  • The RHS says that this weedkiller, whilst remaining in rotted-down compost, should be broken down by microbial activity in the soil. So the answer is to spread it thinly over grassy areas and dig over plots several times a year. It has a soil half-life (half will be gone by this date on average) of 35 days.
  • Hmm. I'm not sure about the above. Surely there are billions (for once not exaggerating) of microbes in a compost heap? Why wouldn't a year's rotting break it down? I need further info here.
  • American research for their EPA submission says it's broken down by sunlight in water after fifteen hours, so don't worry about ponds. 
  • It also has no effect on spurge; ha ha, my euphorbias are safe. 
  • What will make Joe happy? It may kill all his veg, but it also controls marestail. Looks like he might have a clear allotment after all. 

1 comment:

Anonymous said...

Thanks for this - I think it's really worrying