I found this book that talks about a lot of Chinese military technology over the ages. It has a section on land and sea mines starting on 192, but due to the annoying preview limits on many Google books I couldn't get much information on it. The Chinese are known to have been using explosives for a very long time though, so I think its a safe bet they were among the first to make use of land mines. The wikipedia article on land mines claims they might have had something like that as far back as the 3rd century CE, and it cites the aforementioned book. Again, because of the obnoxious preview limits I could not verify that citation. If I have more time later I may look into this more and try to dig up more sources/books, but its definitely not my area of expertise.

Hopefully someone who actually has access to that book could illuminate things for us further. If you're really desperate and no one else gets an answer, I may be able to find the time to check my university's library for it just to look up a few of these things.