Mineral sources of nitrogen

European farmers traditionally rely on ammonium nitrate as the most efficient source of nitrogen.

However, other sources such as urea and UAN are also considered. Different sources of mineral nitrogen do not interact the same way with the soil. These differences need to be taken into account when evaluating agronomic and environmental performances.

Nitrogen - a source of life

Nitrogen is a vital element for plant life. It stimulates root growth and photosynthesis, as well as uptake of other nutrients. However, 99 % of the nitrogen on earth is stored in the atmosphere and less than 1 % is available in the earth’s crust. The nitrogen molecules (N2) in the atmosphere are chemically inactive and cannot be easily absorbed by plants and then exported from the fields by harvesting. It needs to be restored by organic or mineral sources of nitrogen.

Lack of nitrogen results in declining soil fertility, low yields and low crop quality. On the other hand, excess amounts of nitrogen in the soil may move into the ground water, eutrophicate surface water or escape to the atmosphere, causing pollution and climate warming.

Mineral fertilizers

Ammonium nitrate (AN) contains nitrogen as NH₄ + (ammonium) and as NO₃ - (nitrate) in equal portions. Calcium ammonium nitrate (CAN) contains in addition dolomite or limestone.
Urea contains nitrogen in its amide (NH₂) form.
Urea ammonium nitrate (UAN) is an aqueous solution of urea and ammonium nitrate. Conclusions for specialty products, such as NPKs or sulfur containing products, even if not specifically mentioned, can be easily derived from general observations.