It's just another way of saying "organic matter". Every organic gardening book worth it's salt, will at some point get around to telling you that you are going to need to add it on a regular basis.
Why Do I Need To Keep Adding Compost?
The reason is this what you are growing is using it up. In order to build and maintain optimum health of the soil, you're going to have to add some kind of quality organic matter such as compost.
Is Organic Matter The Same As Compost?
Yes, for all practical purposes. What we buy in the stores or online as compost is high density organic matter. The first time most people become aware of organic matter is when they get the results of their soil test and wonder how they are going to raise a low reading. At first you may have purchase a commercially available product to get your soil balanced, however with a little thought and a plan you can easily make your own.
What Is Nutrient Depletion?
No matter what the crop is that you are growing, from beans to Bermuda, it is going to deplete the nutrients and minerals from the soil. Logic dictates that they you must replace them or the soil will deteriorate until it is dead and so is everything you try to grow. This is where the term "Farmed-Out" originated.
But unfortunately, this is where a lot of well intentioned people throw in the towel. They hear that they need compost and they think they have to make their own. You aren't going to compost anything over night. Remember my favorite line "Organic Gardening is a Process, Not An Event. Just get started. Before you know it your compost will be ready for use.
At first you will have to buy retail compost products to get the ball rolling. Whether it is to top dress your organic lawn or amend the soil in your flower beds or build your own soil for container gardening.
New Delta Recyclers Cotton Burr Compost
is available in the Memphis are at a variety of nurseries and garden centers. If they don't carry this tell them you want it! It's local, so your not paying extra for shipping across the country. It's recycled, it's full of nutrients and micro-organisms and they don't dilute it with filler or animal waste.
Why Don't You Use the Stuff they Sell At X-Mart?
Beware of amending your soil with lifeless soil or potting mixes. These are typically made with waste materials and chemicals! Unless you like the thought of that -stay away- from the stuff being sold in bulk stores. No one knows exactly what's in the bag, where it came from, or even when it was packaged.
This is why it is so cheap!
You really do get what you pay for. I suggest calling your local nursery and asking what they carry along the lines of compost. Locally made amendments are always going to be cheaper because of freight costs and typically have higher populations of micro-organisms.
This is a good point in which to discuss the various other organic amendments that are recommended. Here is a partial list of amendments to look for. I say 'partial' because there are new ideas everyday. Some are were common a couple of generations ago only to be 'rediscovered'. Some look promising at first but after the scrutiny of actual use we can't wholeheartedly endorse.