Fibrous sphagnum peats are useful but more expensive than compost or manure. Avoid using dusty fine sedge peats that clog soil drainage. Native Colorado mountain peats are generally inferior for soil amendment purposes and their harvest damages the environment by destroying stream hydrological systems. The best peats come from the northern U.S. and Canada. Manures should be aged for at least one year.
Fresh manure is to high in ammonia which burns plant roots.
Avoid feedlot manures which are typically high in salts. Dairy cattle manure is generally a better quality product for plant growing purposes. Rabbit and poultry manures are fine. Watch weed seed problems from horse or sheep manures. Compost is perhaps the best organic amendment.