Ammonium nitrate fertilizer is an industrially-produced chemical fertilizer. It has the chemical formula NH4NO3 and is used primarily to increase the nitrogen content of soil. This type of fertilizer is typically sold in a granular form, although other preparations and combinations are possible. It is usually inexpensive but may be difficult to obtain because it can be used as an ingredient in the creation of improvised explosives and is thus subject to regulation in some areas.
A standard fertilizer is rated with a series of three numbers, which indicate the concentration of the three most vital plant nutrients in the fertilizer. The first number indicates the percentage of the mixture that is nitrogen, the second number, the percentage of phosphorus, and the third number, the percentage of potassium. Ammonium nitrate fertilizer contains a very high percentage of nitrogen and has a rating of 34-0-0, indicating that if a fertilizer contains only ammonium nitrate, it will consist of 34% nitrogen.
The production of ammonium nitrate fertilizer is a complicated process. Ammonia, one of the key building blocks, is a gas at room temperature, and this gas must be combined with nitric acid in order to produce fertilizer. The end product of this reaction is a solid whitish substance, ammonium nitrate, which is quite stable, safe, and easy to work with. This chemical engineering process, although difficult, can be readily and inexpensively adapted to very large-scale production, meaning that this fertilizer is actually quite inexpensive.
Proper application of ammonium nitrate fertilizer requires an assessment of the qualities of the plants and soil to which it will be applied. Ammonium nitrate can then be applied in sufficient quantities to maintain the nitrogen levels of plants, often grasses or fruit trees, to which it is applied. This fertilizer is inexpensive and safe enough that it can be used in large quantities and over large areas. Typically, plants that have been successfully fertilized with ammonium nitrate will grow more vigorously and show a healthier and greener color, as nitrogen is critical in enabling photosynthesis.
The most significant drawback to ammonium nitrate fertilizer, apart from the relatively complicated process of production, is its occasional use as an improvised explosive. It is one component of a very popular type of home-made explosive, the variety used in the 1995 Oklahoma City bombing. This potential for abuse has led to the regulation of the fertilizer in some regions, despite its widespread use in ranching and agriculture.