Take a Bite Out of Global Warming
MANURE
For healthy plants, proper growth depends on a good supply of soil nutrients. Animal manure is a great source of nitrogen and other important nutrients, as long as the manure comes from cows that are fed a natural diet and are not given artificial growth promoters or antibiotics. You will also want to be cautious with your rates of manure application, to prevent runoff and excessive methane emissions that occur as manure decomposes. The West Virginia Master Gardener Association suggests no more than 10-15 pounds of manure per square yard. So if your garden is about 50 square feet (over 5 square yards), then 50 pounds would be plenty, especially if you are also mixing in compost.
Univ. of Missouri Extension: How and Why to Use Manure
Organic Gardening Magazine: Fertilizing Your Garden
You can buy manure from a nursery or garden center, but be sure that the manure comes from organically raised animals to avoid manure laced with antibiotics and hormones. You might also be able to buy manure straight from a local farm, in which case you would want to heat it up and dry it out before using it. You can do this by covering it with a plastic tarp to heat it up and kill any possible pathogens.
A project for the Center for Food Safety and the CornerStone Campaign