No I don't have that info. And any info anyone might have on any other studies that were done prior to the past two years is pretty much invalidated by a recent finding.
Previously it was thought that the total number of microbe species in the soil was numbered in the tens because scientists were only able to grow about 50 species on Petri dishes in the laboratory. Now, with the popularity of DNA testing, it has been determined that there are on average 25,000 different microbial species in farm land and 45,000 different species in old growth forest.
Clearly this DNA analysis overwhelmed the previous thinking. All but 50 or so species are unnamed, let alone studied over the long term.
I can say that corn and corn gluten are digested by the microbes within a few days if there is any moisture at all. I'm not sure how you would measure any residual after digestion. Every molecule is consumed by another species of microbe or macrobe. And those microbes are consumed by other species in a food chain that is 25,000 species long and circular in places. I'd lose track of that real fast.
One more thing to add to this topic (thousands of species): I think the whole reason there is a SUDDEN increase in interest in organic gardening is this discovery of all the microbes. Because suddenly there is a reasonable explanation for why the methods and materials work. Before this discovery, the theory was this: "You apply compost, suddenly a miracle happens, and the grass gets green." Now we know that it is the microbes in the soil that manufacture plant food and share it in return for sugar in a symbiotic relationship with the plants.
I agree that organics and synthetics have their own place. That's why this forum started to keep them separated. The place for organics is on the lawns of people who want them. Hopefully with enough people writing in we can find the way to fulfill the desires of the clients without going to jail.
Moderator, Organic Lawn Care Forum
San Antonio, TX