The "tunnels" on the surface sound a lot like the work of voles to me. Whether they'd be attracted by the SBM, I don't know.

Here is one link with information, including some photos of vole tunnels.

Here is another link.

Interesting. Looks like the Prairie Vole likes grain. I wouldn't have noticed it since the grass is taller (about 4"), but I was out looking for weeds to pull! There does not seem to be a "burrow", but a definite path through the grass when I seperate the blades. Looks like I can get some mouse traps to see what I can capture. Also noticed more very large birds flying over that area so they may be taking care of them for me.

Update - I caught a vole last night.. it was running across the grass where I was mowing. Little guy tried to bite me. Strange that I have not seen them until this year when I started putting down soymeal.

Once you get some hawks and/or owls in the area you should see the "problem" diminish pretty quickly...

When you first stop using synthetic materials, it sometimes takes the birds, frogs, and lizards a few months to return. Once they do, they will be eating the bugs that your voles are coming to eat now. You can get birds back with bird feeders, bird baths, and bird houses.

Thanks dchall san antonio, I have a pond in the backyard and established a habitat for birds/frogs and even have a couple snakes. There have been a great deal of martins hanging around lately as well. I did find a couple nests in my yard that they had started, but removed them and have not seen any new ones lately... Now those crazy moles are something else to talk about.

I never mention snakes because of the negative connotation, but yes, they do come with the organic program...along with lizards, toads, and bird. The main point is that when you no longer use ANY insecticide or herbicide, your garden is suddenly very hospitable to all the natural predators. A natural balance will occur. When that happens, natural predation takes care of the bad guys including voles, moles, etc.

Awesome! It is too cool to see the changes that have taken place this year due to going organic in my lawn care. Now see birds that look like yellow canary's and the robins put their nests in my trees/spruces. The snakes I see are harmless and non threatening. The only thing I do not enjoy is those hornets.