The advantages of Urea versus CAN

Urea can offer farmers environmental as well as economic benefits.

Food Wise 2025 sets out a cohesive, strategic plan for the development of Ireland’s agri-food sector over the next decade. The main obstacle to achieving its ambitious targets continues to be a need to reduce greenhouse gas (GHG) emissions from agricultural production. Any increase in intensification must take place in the context of reduced greenhouse gas emissions. Therefore, a focus on strategies that enable the sustainable expansion of the dairy sector is essential.

Using the correct fertilisers will prove critical in getting the most from our limited land base. Farmers should note the benefits of using Urea over other forms of Nitrogen, mainly CAN.

Urea

Urea has the highest nitrogen content of all solid nitrogenous fertilizers in common use. More than 90% of world industrial production of urea is destined for use as a nitrogen-release fertilizer. Urea is made up of 46% nitrogen and is more widely available than calcium ammonium nitrate (CAN) internationally.

Urea is an extremely mobile substance in soils because of its negative charge and is a major cause of water pollution from agriculture. It is readily absorbed by plants, and is the dominant source of nitrogen for plant growth. Urea is used in many multi-component solid fertilizer formulations and is highly soluble in water.

Urea is usually spread at rates of between 40 and 300 kg/ha but rates vary. Urea is not compatible with other fertilizers. In irrigated crops, urea can be applied dry to the soil, or dissolved and applied through the irrigation water. As the N rate increases the percentage of NH3 loss from urea increases. Urea is susceptible to ammonia (NH3) loss during its conversion to ammonium-N.

CAN

Calcium ammonium nitrate or CAN, also known as nitro-limestone, is a widely used inorganic fertilizer, accounting for almost 4% of all nitrogen fertilizer used worldwide.

CAN had the highest and most climatically sensitive emissions of the greenhouse gas nitrous oxide (N20)

The importance of Lime

Liming acidic soils to correct soil pH will result in increased grass and crop production annually. It will also increase the release of soil N by up to 80kgN/ha/year, increase the availability of soil P and K and micronutrients and increase the response to freshly applied N, P & K as either manures or fertiliser.

Conclusions

Urea costs less, gives comparable yield performance to CAN but total N recovery is lower. Urea based Nitrogen offers potential to sustain or increase national N usage with reduced emissions of greenhouse gas nitrous oxide.

First Published 12th April 2016