So, had a couple of guys over that I met at the local farmer's market last weekend to show them airlayering, talk figs/fruits/produce and whatnot. 

The tree I was airlayering (Gino's black/4th year) was RKN-infected, so I showed them the roots as an example of what RKN infection looks like with figs.  I mentioned that I was going to plant the tree in our community garden, which was overrun with RKN.  Then came the question:  Why aren't you guys using Sudan Grass?

Did some research on it, there's a lot of info out there.  This probably isn't necessarily useful for the small-scale stuff or pot culture as a lot of us are doing, but this gives a basic idea:  http://www.hort.cornell.edu/bjorkman/lab/covercrops/rkn.php

There is a ton of info out there above and beyond this.  If anyone wants to read more, see:

https://www.google.com/search?q=sudan+grass+rkn

Jason, this is very interesting.  I don't think we have a problem with nematodes here, but you never know.  I know others here have problems.  Nice info!  Thanks for sharing!

Suzi

I noticed they specified Northern RKN I wonder if the effects are the same for other Nematodes annd if the NRKN is the one that plagues Figs. I know there is a Nematode that attacks citrus trees that live in the sandy citrus belt in Florida. That Nematode requires a dry sandy soil and a damp organic soil stops it.

A possibility is that Sudan Grass and the related sorghum and Johnson Grass produce a fair amount of cyanide especially in new growth. It is rarely enough to affect larger animals aside from discouraging excessive grazing and many plants produce cyanide. Yup -  http://cru.cahe.wsu.edu/CEPublications/eb1950e/EB1950E.pdf