Nitrogen: a basic building block of life

As a component of DNA/RNA, amino acids and protein, nitrogen is one of the primary building blocks of life. In plant nutrition, it is vital for increasing yields and ensuring an adequate food supply. Researchers estimate that about half of today’s food supply is dependent on the nitrogen originating from ammonia-based fertilizers. (Erisman et al. 2008)

As well as making abundant harvests possible, nitrogen is critical for ensuring the protein content of crops. Restrictions on nitrogen fertilizer use in Denmark correlate with a decline in the protein content of wheat grown for animal feed. This has implications for animal and human health and for the environment because it means that more crops would need to be grown to obtain the same amount of protein. (Knudsen 2003)

While it is important to recycle organic sources of nitrogen, such as animal manures, these do not contain sufficient amounts of nitrogen to feed today’s global population. Substituting farmyard manure for the current supply of mineral fertilizers would require at least a fourfold increase of livestock worldwide. (UNIDO/IFDC 1998)

There is a public perception that nitrates, often related to the use of nitrogen fertilizers, in drinking water pose a health risk. The most common concerns relate to infant methemoglobinemia (Blue Baby Syndrome) and gastric cancers. In the first case, bacterial contamination now seems to be the critical factor, which explains why cases of the syndrome have become rare in developed countries, although they tend to have higher levels of nitrates in drinking water. Rather than confirming the nitrates-cancer link, further research has contradicted earlier findings: groups consuming large quantities of fruits and vegetables – the principal sources of dietary nitrate – demonstrate lower rates of gastric cancer. (IFA 207 and UNEP/WHRC 2007)

Excess nitrogen in certain aquatic ecosystems is known to be associated with eutrophication. One consequence is algal blooms, which may produce toxins that make the water unfit for bathing and render locally produced shellfish temporarily unfit for human consumption.

In its chemically reactive forms, nitrogen is extremely mobile within its natural cycle . Therefore, the widespread use of nitrogen fertilizers cannot be divorced from health effects of other forms of nitrogen elsewhere in the cycle. Poor management of fertilizers could therefore be a contributing factor to negative health impacts related to airborne forms of reactive nitrogen (ozone, particulate matter, etc).

Both organic and inorganic forms of nitrogen can be implicated in these unwanted impacts. Integrated management of all sources of nitrogen is therefore critical in order to minimize undesired impacts. In this context, the fertilizer industry promotes Fertilizer Best Management Practices (FBMPs) that involve using the right product @ the right rate, time and place^TM, and IFA has developed a global framework to encourage the translation of this principle into locally adapted practices.

Nitrogen product safety