What is the main difference between organic and inorganic fertilizers?

Answer Details

The main difference between organic and inorganic fertilizers lies in their origin. Organic fertilizers are derived from natural sources - decomposed plant matter, animal manure, compost, bone meal, fish meal, and other biological materials. Inorganic (mineral or synthetic) fertilizers are manufactured through industrial chemical processes, such as the Haber-Bosch process for producing ammonium-based nitrogen fertilizers or the treatment of phosphate rock with acid to produce superphosphate.

The other options contain inaccuracies:

• Inorganic fertilizers are generally more polluting than organic fertilizers, not less. They are a major source of water pollution (eutrophication) and can degrade soil structure over time with excessive use.
• Organic fertilizers are not necessarily more readily available than inorganic fertilizers. In fact, inorganic fertilizers are often easier to obtain commercially, especially in urban areas.
• The claim that organic fertilizers provide only micronutrients while inorganic fertilizers provide only macronutrients is incorrect. Organic fertilizers supply both macro- and micronutrients (albeit in lower, slower-release concentrations), and inorganic fertilizers can be formulated to include micronutrients as well.