That is grossly exaggerated. While synthetic fetilizer interfers with natural soil activity,it certainly doesn't render it usless. Just start your organic program and all will soon be fine.
And remember,I Heard and They Said are both bad about telling lies.

Using "fertilizers" to the exclusion of organic matter can cause a soils life to go dormant, or leave, but does not necessarily require soil replacement. Soil is composed of the mineral portion, the sand, silt, and clay, that makes up the soil type you have and organic matter, the stuff the Soil Food Web lives on and converts into nutrients that feed the plants that are trying to grow in that soil.
We know that using synthetic "fertilizers" without adding organic matter can change soils for the worse, changing the soils pH, causing compaction, requiring that larger doses of "fertilizer" be applied to get the same results, creating an unhealthy environment for the plants to grow in resulting in greater needs for insect pest and "weed" control.
Soil exhaustion resulted from using up the organic matter in the soil and not replacing it, although the use of synthetic "fertilizers" contributed to that by masking, for a time, the lack of organic matter in the soil.

Use the smallest possible amount of fertilizer, and only if your plants are showing signs of a deficiency.

The "soil exhaustion" claims mostly come from areas and eras where crops were planted in unsuitable places, with poor management practices. Much of the loss came from erosion because contour plowing was not common and sharecroppers couldn't afford to have any fallow land or cover crops. (they couldn't afford fertilizer, either)

The only "fertilizer" I use in quantity is soil sulfur, because we have salic alkaline soil. Ammonium sulfate or ammonium nitrate lightly on the veggie beds if they need it.

Even 'exhausted' soil can be brought back to life by replacing lost organic matter, nutrients and microbes with a magical concoction known as...compost.

This post was edited by toxcrusadr on Tue, Mar 25, 14 at 12:03

Organic fertilizers are essentially organic matter - plant parts or animal byproducts. If you use these types of products (as opposed to synthetic, petroleum-based fertilizers), you will actually encourage beneficial soil organisms rather than destroy them.

Organic matter via compost is great but often is insufficient to provide the nutrient needs of edible crops. Rapid growth and the removal of the plant at harvest can deplete nutrient levels. It is often suggested to supplement whatever organic matter one uses with an organic fertilizer to maintain peak nutrient availability.

Thank you everyone for the lovely replies! Very informational and helpful :) I will use organic fertilizers apposed to synthetic.

Many people think that because tests of compost do not show many nutrients that compost has few and needs supplements. Many of us that have used nothing but compost, and other forms of organic matter, know that our soils have ample amounts of nutrients as a result of the good reliable soil test we have had done over the years which show an increase in all of them.

@kimmsr so you're saying fertilizers are not really necessary as long as you have good nutrients in the soil and one way is by adding compost?

Point of order, slightly off topic, possibly splitting hairs, re 'Synthetic' and 'petroleum based' fertilizers.

Let's look at the typical granular fertilizer. N from ammonium nitrate, which is produced from natural gas and nitrogen at a high temperatures. P from mined phosphate rock, bat guano, etc. K from potash, which if I remember correctly, is mined. None of this is really made from petroleum, and with the exception of the nitrate, it's mined rather than chemically synthesized.

Of course, there is a large investment of fossil fuel involved in the mining, processing and transportation. Something like 2% of the world's production of natural gas goes to make fertilizer. So none of this changes the fact that a bag of granular fertilizer has a huge environmental footprint compared to compost or organic fertilizers.

Soil nutrients become depleted over time and this can happen easily and rapidly over the course of a growing season with edible crops that pull a lot of nutrients from the soil. Often, the typical annual application of compost is insufficient to supply all the ongoing nutrient needs of these crops to maximize their growth and potential. Organic fertilizers are often used to supplement this nutrient demand.

There is nothing to be ashamed about or made to feel inferior if one resorts to using organic fertilizers - they are, after all, just as much comprised of organic matter as is compost or aged manures. They just supply it in a bit more direct and concentrated manner. They are every bit as much encouraging of an active and diverse soil microbial population as they require the input of these organisms to make the nutrients available to the plants. They are not harmful when used as intended and they are often less of an impact on pollution than even compost or manure applications, which can produce leachate that pollutes groundwater and streams.

And yeah tox, that is splitting hairs a bit :-) But let me split them a bit further - "granular" fertilizer is not limited to the synthetic or manufactured product. A large number of blended, premixed organic fertilizers come in a granular formulation. 'Granular' is only a method of presentation, not reflective of an actual type of product. But we agree on the end result :-))

I had nothing to add on the subject until I realized for once I agree with both kimmsr and Tox in a single thread. ;)
While the use of grainulars mentioned by Tox might have little to no long term negative effect on soil health, timing,amount used and watering are more critical to reaping benifits and/or avoiding harm to that season's crop. Not to imply organic is only for dummys,but mistakes in application amount,timing and over/under watering are less telling. Amount of product or material used is well understood,the other two not so well. Allthough it's somewhat applical to P&K , timing of granular N is critical. Too early and it's gone by the time plants need it. Applied at proper time but followed by insuffecent/excessive moisture,albeit temporary will miniumize benifits to plant. In addition to helping smooth the hills and valleys mentioned above,the lesser amounts of nutrents in compost are easier to utilize when needed. Similar to a bushel of green beans. One way cooks them all to be eat before they spoil. The other cooks a single meal and preserves remainder for later use. The casual observer sees the intire bushel in the pot and declars you have beans in abundance. I don't know about you but making all that up almost sapped my brain.

Thanks for the info. I did wonder if just the compost was enough also, since I see it listing very low NPK values on the retail bags. At the same time, the other kinds of fertilizers that might specialize for a certain result (such as blooms or greenery) have higher values that, assuming if composting or other materials were enough already, we wouldn't necessarily need to use those specialized fertlizers either.

Once I incorporated adequate amounts of organic matter into the soil and changed the soil tests from a pH of 5.7 and low optimum levels of Phosphorus (P) and Potash (K) and the Calcium (Ca) and Magnesium (Mg) levels not in balance to a soil pH of 7.0 and high optimum levels of P and K and Ca and Mg in balance, without using any type of "fertilizer", organic or synthetic, plants grew quite well with few insect pest or plant disease problems.
Until the levels of organic matter reached those optimum levels not even adding "fertilizers" made much difference.

All good points folks. When I used the term granular fertilizer I was referring to typical non organic lawn fert or triple 12 purchased in a bag. I did not want to confuse the issue with my selection of terms, but apparently by not selecting any terms I confused the issue. :-]

One point about 'low' NPK levels in compost: yes they are low, but you're also using compost by the pound and fertilizer by the pinch. 100 lb of compost has a pound or two each of N,P and K. I'm not arguing whether this is enough for any particular garden, just that you should consider nutrient mass added to the soil rather than just % in the product.