Good general soil mix - 1/3 sphagnum peat moss, 1/3 compost, 1/3 aeration material (pumice, perlite, lava rock, rice hulls, etc). To that I would add at approximately 1 cup/cubic foot
1. Kelp meal
2. alfalfa
3. rock dust (more like 4 cups for this amendment)
4. fish bone meal
5. neem or karanja meal or cake
6. crushed lobster, shrimp or crab shells....chitin!
There are other amendments as well but the most important thing to get right is the basic soil mix and then work on the amendments. You can get kelp, alfalfa and rice hulls in large bags very cheaply at your local feed store. Rock dust might be located at a local quarry, monument or kitchen counter top place for free. Depends on where you are at if you can locally source crushed shell but if not you can buy it on line. Neem and/or karanja - you'll probably need to purchase on line. Both the neem and karanja are great slow release nitrogen and help keep pests at bay as well. The shells are great sources or calcium and chitin helps fight pests too.
Also, think about starting a worm farm. You'll end up with a fabulous source of compost for your soil and teas. And just for fun a great book is - Teaming with Microbes which is really a good read and provides a lot on insight on organic growing. Another free and great source of compost - leaves. Get a large 3 x 3 minimum pile of leaves and just let is sit and rot. In a year, you'll have great compost - leaf mold.
I would guess that the horse compost is the best of the three followed by goat and then pigeon. Make sure it is well composted.
