Calcium Ammonium Nitrate (CAN) is a widely utilized granulated mineral fertilizer, primarily valued for its high nitrogen content and its balanced nutrient delivery to crops. It is a dual-nutrient product, supplying not only the primary macronutrient nitrogen but also the secondary nutrient calcium, which is important for plant structure and soil health. This combination offers an effective solution for farmers looking to maximize crop yield and quality while maintaining soil integrity.
Chemical Makeup and Physical Form
Calcium Ammonium Nitrate is manufactured by combining ammonium nitrate with a material like powdered limestone or dolomite. The final product is a mixture that typically contains about 25 to 28% total nitrogen and 6 to 10% calcium. The composition is processed into small, free-flowing granules or prills, typically white to light gray or beige.
The fertilizer is highly water-soluble, allowing the nutrients to dissolve quickly and become readily available for plant uptake immediately following application. The nitrogen component is split into two distinct forms: nitrate nitrogen (NO3-) and ammonium nitrogen (NH4+). Most commercial grades of CAN maintain a balanced 50:50 ratio of these two forms. The inclusion of calcium makes CAN chemically stable and influences its physical properties, making it less hygroscopic and more stable than pure ammonium nitrate.
Agricultural Advantages as a Fertilizer
The unique blend of nitrogen forms in CAN provides a significant agronomic benefit through its dual-action nutrient release mechanism. The nitrate nitrogen is immediately available and quickly absorbed by plant roots, promoting rapid vegetative growth and photosynthesis. Simultaneously, the ammonium nitrogen is held more securely by soil particles, where it is slowly converted by soil microbes into the nitrate form over time. This slower conversion process ensures a sustained supply of nitrogen, which is available to the crop throughout its full growth cycle.
The calcium component, typically derived from limestone, plays a crucial role in mitigating soil acidity. Unlike many nitrogen fertilizers that increase soil acidity over time, the presence of calcium carbonate acts as a buffer, helping to neutralize the acidifying effect. This pH-neutral or slightly alkaline property helps preserve soil health and supports a robust environment for beneficial microbial activity.
Beyond its role in pH management, the calcium supplied by CAN is a secondary nutrient important for plant physiology. Calcium strengthens cell walls, contributing to overall plant rigidity and improved resistance to disease. It is also directly involved in cell division and root development, promoting a healthier root structure. The supply of calcium is known to prevent physiological disorders in specific crops, such as reducing the occurrence of blossom end rot in tomatoes or fruit cracking in apples.
Safety Guidelines and Storage Requirements
Due to the nature of its components, handling CAN requires adherence to specific safety and storage protocols to minimize risks. When handling the granulated product, individuals should wear appropriate personal protective equipment, including gloves and protective eyewear, to prevent direct contact. To minimize inhalation exposure, adequate ventilation or a particulate respirator is advised, as breathing in the dust generated during handling should be avoided.
For storage, the fertilizer must be kept in a cool, dry, and well-ventilated area, away from direct sunlight and any heat sources. A main storage precaution is to maintain strict segregation from incompatible or combustible materials, such as fuels, oils, organic materials like sawdust, or other chemicals like alkalis. This is necessary because the nitrate content can intensify a fire, although CAN itself is not classified as an oxidizer like pure ammonium nitrate.
In the event of a fire involving CAN, only large quantities of water should be used for extinguishment, as smothering or using chemical extinguishers may be ineffective or even hazardous. Securing the storage area with perimeter fencing, locks, and lighting is recommended to prevent unauthorized access or theft.