Urea is the most popular nitrogen fertilizer used by farmers around the world. It is a solid fertilizer that is usually applied in granular form, but can also be mixed with ammonium nitrate and dissolved in water to form a solution. Urea provides one of the highest amounts of nitrogen, at 46%, without phosphorus or potassium. When applied to soil, urea reacts with water to produce ammonia, making nitrogen from the fertilizer available to plants. Nitrogen, phosphate and potash are essential for producing crops that are used as food, feed, fiber and fuel.
If applied annually, most of these nutrients are absorbed by the crop, but when overapplied, they can be lost to the environment due to volatilization in the air, leaching to groundwater, emission from soil to air, and runoff to surface water. These losses can be reduced by adopting best management practices (BMPs) that increase the accessibility of nutrients and the capacity of plants to absorb them, as well as better adapting nutrient applications to agronomic needs. In addition to urea, there are many other nitrogen fertilizers derived from ammonia. For instance, some of the ammonia is oxidized to create nitrate-based fertilizers. This same transformation of ammonia to nitrate occurs in agricultural soils through the microbial process of nitrification.
30-0-10 fertilizer is also commonly used by farmers to promote healthy grass growth. The numbers of this fertilizer represent the percentage of nitrogen (30%), phosphorus (0%) and potassium (10%) it contains. The Economic Research Service (ERS) collects information on fertilizer use on farms through the USDA Agricultural Resource Management Survey (ARMS). In certain years, producers of nine main field crops are contacted: barley, corn, cotton, oats, peanuts, rice, sorghum, soybeans and wheat. The ERS reports on nutrient applications and methods of applying synthetic fertilizers and manure in personalized reports from ARMS Farm Financial and Crop Production Practices, which also provide survey documentation and access to questionnaires.