The Great Debate: Organic vs. Mineral Fertilization
Growing "organically" involves fertilizing plants with only organic fertilizers. Organic fertilizers are derived from organic sources, more specifically, it must contain carbon. The nutrients in organic fertilizers must be broken down by microorganisms in order for them to be usable by plants.
Mineral based fertilizers on the other hand, are immediately available for plants to use for growth.
The only difference in the nutrients in organic fertilizers vs. mineral based fertilizers are the nutrients in organic fertilizers once part of living tissue.
An example that I like to use often when educating folks on this topic is using compost (organic) as a source of nitrogen fertilizer vs. using ammonium nitrate (mineral salt).
Ammonium nitrate is immediately for use by plants because it is already in a form that plants can use: ammonium (NH4+) and nitrate (NO3-). The compost provides the plant with both ammonium (NH4+) and nitrate (NO3-) but these ions are incorporated into organic matter which must be broken down by microorganisms to release them before they can be used by plants. There is no difference at all in the NH4+ and NO3- in inorganic salts and the NH4+ and NO3- that once was part of the compost. In fact, the nitrogen that is in the compost was at one point nitrogen gas in the atmosphere. All nitrogen that has ever been incorporated into living organisms was nitrogen gas in the atmosphere that was fixed into ammonia (NH3) through a natural process called "nutrient cycling". Certain plants such as legumes can fix nitrogen directly from the air. Ammonium nitrate is made using the "Haber Process" which uses energy to take nitrogen out of the air and turn it into a salt that can be used as fertilizer. This salt is very pure and only consists of NH4+ and NO3- that is immediately available for plant uptake.
In conclusion, nitrogen is nitrogen regardless if it was part of decomposed compost or a mineral salt. In fact, all nitrogen that is part of all living organisms was once gas in the atmosphere and vice versa. Plants just need it to be in 2 forms to be used NH4+ and NO3-. Nutrient cycling is responsible for this. ALL plant nutrients are part of a nutrient cycling process regardless if the nutrients are liquid in a bottle or decomposing organic matter. All elements in organic matter could have at one time been considered "inorganic".