http://www.powen.freeserve.co.uk/Basics/fertilisers.htm#Orgfert

In this link u can get a table of contents used in organic fert

Organic Fertilizer

Advantages – Organic nutrients include such things as cow, sheep, poultry and horse manure. (One should avoid using pig, dog or cat feces because of the problems involved with internal parasitic worms which may be transferred to humans.) Bonemeal, bloodmeal, compost, and green manures will also provide nutrients for your plants.

There is less danger of over-fertilization by adding decomposed organic material to a garden. It provides a slow release of nutrients as micro-organisms in the soil break the organic material down into an inorganic, water soluble soluble form which the plants can use. The addition of organic material improves soil structure or “workability” immensely. It also vastly improves the water-holding capacities of sandy soils, a distinct advantage in arid climates such as ours.

Disadvantages – For the most part, organic fertilizer is not immediately available to the plants. As noted above, this “slow- release” feature can be an advantage. However, if there is an immediate need for nutrients, organic fertilizer cannot supply them in a hurry. Furthermore, information on the amount of nutrients and the exact elements in an organic fertilizer such as manure is not readily available to the home gardener. In contrast, when you apply manufactured inorganic ferilizer you know the kinds and amounts of the elements it contains, and this allows you to be more precise in meeting a plant’s nutritional needs.

The possibility of nitrogen depletion is another drawback of organic fertilizers. Because of complex bacterial action, the addition of a large amount of organic material can cause a temporary nitrogen depletion in the soil and therefore in the plants.

I hate to disagree with Crystal, but given the choice between eating fruits and vegetables washed with chlorine to remove harmful bacteria or eating dirty stuff and getting e-coli or listeria, I’ll take the chlorine every time. Besides, I bet Crystal drinks chlorinated water. Plant nutrients are the same whether if comes in a commercial fertilizer source or an organic source. N,P and K are all the same no matter what their source is. Using fertilizers from any source increase yields, meaning more production from fewer acres. Discontinue fertilizer use and it would require many, many more acres to be cultivated. Those additional acres would have to be more fragile soils (as in erosion), wetlands drained, forested land cleared, land currently supporting wildlife, etc. The more acres under cultivation, the greater the use of fossil fuels to cultivate that land. Disadvantages of any organic or inorganic fertilizer is that misuse, overapplication or application at the wrong time of year can result in the nutrients entering water sources. This can cause excessive aquatic plant growth or as in the case of nitrogen, “blue baby syndrome” (look it up). Politics? People are politics, plain and simple. If you want to eat, you can either grow it yourself, pay me to grow it or starve. If I can’t make any money growing a certain crop, then I won’t. If you want me to grow you that crop, then you better make it financially worth my while to do so because I can’t pay my bills by doing charity work for you. That’s politics. Regardless of whether it’s growing food, building cars or running Yahoo Answers, there’s always going to be someone doing the work and there will always be someone making money. Sometimes those are the same person, other times not. That’s the way it is and the way it has always been ever since the first caveman traded a handful of berries he picked in exchange for a wooden club someone else made. Monsanto and Tyson are no different than GM or Hasbro. If they can make money building a product we want, they’ll do so. When the demand is no longer there and we stop buying it, then they will stop making that product and look for or invent something that we will buy. It’s called business but it’s human politics just the same.

Organic fertilizers are all natural, no chemical fertilizers. Manure and compost are good examples. The advantage of using them is the fact that they do not contain man made chemicals as well as you are recycling.

Organic vegetables tend to be more tasty, that is what I have found.

There are some good links. They should get you started. Good luck!

http://www.ext.vt.edu/departments/envirohort/factsheets2/fertilizer/jan89pr6.html

http://www.masslive.com/metroeastplus/republican/index.ssf?/base/news-1/1145348253141170.xml&coll=1

http://www.ces.ncsu.edu/cumberland/fertpage/organic.html