I've no experience with RKN, but there's a fair bit of buzz and research using chitinous shells, meal, for example
http://www.ncbi.nlm.nih.gov/pubmed/18678924.
The action is probably mediated by
Trichoderma harzanium population increasing in the amended soil. The nematode eggs are made of chitin too - so Trichoderma will destroy them, besides other reported effects of increasing plant resistance.
Here's an example of research on Trichoderma where chitin is used to supplement the media where it's grown.
http://www.sciencedirect.com/science...38071708001193
