Just a slightly different take on this. Bagged manure available around here from the box stores has a VERY low content of actual manure -- in most cases only about 10%. Yes it can provide some tilth to the soil but very little in terms of fertility, and in my experience does not really add much to the soil. Mushroom compost, on the other hand, is made up virtually completely of composted manures and has a much higher organic/manure content than the bagged manures available here. Unfortunately, where I live mushroom compost is virtually impossible to find, none of the stores sell it and it is no longer available in bulk any where in SE Michigan that I know of. I did manage to get one load of mushroom compost about 5 years ago and used it as a soil amendment in areas where lime loving plants grow, like hellebores and clematis. Those plants grew like crazy! I know it is somewhat basic but that can be corrected depending on what you are growing and your natural soil pH. I know at Ashwood nursery in England, probably the premier hellebore nursery in the world, they made beds largely of mushroom compost, and their hellebores in the garden were to die for. So....take from that what you want, but wish I could get some more mushroom compost. Having said all that, if you have made beds the way you describe and are adding that much organic matter every year, your soil is probably in great condition and you probably only need to amend or fertilize around hungry plants (clematis, roses, hellebores....) BTW, dehydrated manures are sometimes available bagged, and while much more expensive than the box-store bagged "manures", add much more fertility and tilth to the soil IMO.

I realize that this isn't what you asked for, and I don't actually have specific knowledge about cattle ranching on that side of the triangle; but in North Carolina, one is never far from some serious rural farming and ranching. Some of these folks need to get rid of their manure. Some go so far as to pile it and turn it so that it becomes compost faster and they sell it at reasonable prices. You just need to ask around (once you get here), and someone will know someone else who can point you in the right direction.

www.southernlandscapesupply.com Stopped by the other day, they had composted horse and chicken manure. Hope this helps!

Try Mt. Scott Fuel, 6904 SE Foster Road (503)774-3241. They have various composts in bulk, and deliver.