[scs]

Hi,

We are on chalk and flint in the SE so our horse paddocks have become compacted and a bit sparse/weedy after the drought conditions of the last two summers.  I have been harrowing and will be topping to try to improve the health of the paddocks over time.  We have what looks like Nostoc commune in a few of the paddocks that have been grazed before being harrowed (we left a few on rotation).  These are now due to be harrowed, but am I ok to do that with the Nostoc or will I spread it even further?  My understanding is the healthier the grass the less likely we are to get more Nostoc, so does that mean go ahead and harrow to try to help the paddocks?   We will leave the horses off the paddocks for at least 6 weeks after harrowing.

[doganjo]

Are you in the UK?

Among the photosynthetic micro-organisms, cyanobacteria, belonging to the genus Nostoc are regarded as good candidates for producing biologically active secondary metabolites which are highly toxic to humans and other animals.

[Fleecewife]

On the other hand, this:

The bottom line is that [/size]Nostoc commune[/color][/size] and other mat-forming members of this genus are not toxic; they cause no harm to plants or animals including harm to the health [/color]

Apparently Nostoc is sometimes confused with blue-green algae, which is of course toxic.

[doganjo]

I googled Nostoc, is that what you did?    

That's the problem with the internet - so many different answers to questions.

"Ye pays yer money an ye taks yer chance" 

[Fleecewife]

Yes    of course  because I'd never heard of it, or seen it.  Sounds a bit like a Russian group living village  .  What I didn't find was anything useful on whether or not disturbing it by harrowing will cause it to spread, just a link to TAS and this question