Nitrogen makes up 78% of Earth’s atmosphere; it is an essential building block for life, and it is also a topic of many water quality discussions in Iowa.
With Iowa’s water nitrate level a concern for many, it is understandable that people have questions like what it is, how it works, and why farmers are putting it on their fields. To understand these questions, we first have to understand the cycle that nitrogen goes through during the agricultural growing season- appropriately named the nitrogen cycle.
To get a good grip on the nitrogen cycle, visit our new page and watch IAWA’s new animated video on the topic. It breaks down the cycle’s steps, the factors at play, why it matters, and how we can harness it to our advantage.
The video, accompanied by a matching web page, explains concepts of
Fixation – Where some plants can pull nitrogen (N2) from the atmosphere into the soil and turn it into ammonia (NH3).
Nitrification – ammonia is then converted several times to end up as nitrate. This is the most plant-available and water-soluble form of nitrogen. In Iowa, this happens in the early spring. That can be problematic, as there are no plants on the fields to absorb the nutrients, and heavy rain can wash some of them downstream.
Assimilation – After planting, crops absorb nitrates from the soil to form proteins and grow. This is a key step: if there is not enough nitrogen, the plants cannot grow enough for a good harvest. This is where we add nitrogen fertilizer as a supplement.
Ammonification – Once the crops are harvested, they leave behind residue and debris. Living organisms in the soil, like bacteria, decompose it into ammonium.
Denitrification – From there, it undergoes multiple processes that can either store the leftover nitrogen in the soil bank or return it in a gaseous form to the atmosphere.
The video also covers different science-backed methods that farmers can, and are, using to prevent these nutrients from running off the fields and into Iowa’s water sources. Practices in the field and around it can make a huge difference, and numerous resources are available to help fund and implement them.
Practices like cover crops, reduced-tillage, prairie strips, and nutrient management are just a small selection in the conservation arsenal of Iowa’s farmers. For support and resources to implement these practices, visit the Conservation Compass at TheCompass.ag.