Calcium Nitrate Tetrahydrate (CNT) vs. Calcium Ammonium Nitrate (CAN): Two Key Calcium-Nitrogen Fertilizers

Calcium and nitrogen are two essential nutrients in crop production. Nitrogen plays a central role in protein synthesis, chlorophyll formation, and plant metabolism, while calcium contributes to cell wall strength, membrane stability, root development, and fruit quality.

Calcium Nitrate Tetrahydrate (CNT) and Calcium Ammonium Nitrate (CAN) both supply nitrogen and calcium, but they differ significantly in product form, nitrogen composition, production process, and application method.

1. Calcium Nitrate Tetrahydrate (CNT)

The typical chemical formula of Calcium Nitrate Tetrahydrate is:

Ca(NO₃)₂·4H₂O

It is generally produced by reacting calcium carbonate, such as limestone or calcite, with nitric acid. The resulting calcium nitrate solution is purified, concentrated, and crystallized to obtain the tetrahydrate.

The main reaction is:

CaCO₃ + 2HNO₃ → Ca(NO₃)₂ + CO₂↑ + H₂O

CNT is typically a white crystalline product with excellent water solubility, although it is relatively hygroscopic.

Key Characteristics

• Nitrogen is supplied mainly as nitrate nitrogen (NO₃⁻-N).

• Provides rapidly available, water-soluble calcium.

• Highly soluble and suitable for preparing nutrient solutions.

• Well suited for fertigation, soil drenching, hydroponics, and certain foliar calcium applications.

• Hygroscopicity requires proper packaging and dry storage conditions.

In modern intensive agriculture, CNT is particularly valued for its combination of rapid calcium supply and immediately available nitrate nitrogen.

Crops such as tomatoes, peppers, cucumbers, grapes, citrus, and strawberries often have relatively high calcium requirements during fruit development. Adequate soluble calcium nutrition helps support tissue strength, fruit firmness, and overall quality.

2. Calcium Ammonium Nitrate (CAN)

Calcium Ammonium Nitrate is not a single pure chemical compound. It is generally a compound or blended nitrogen-calcium fertilizer based on ammonium nitrate combined with calcium-containing materials.

Depending on the manufacturing process and product specification, commercial CAN formulations vary considerably. Total nitrogen content commonly ranges from approximately 15% to 27%.

One widely used field-grade specification is:

N 27% + CaO/MgO

Lower-nitrogen, higher-calcium grades are also available for specialty fertilizer markets, for example:

N 15.5% + approximately 26% CaO

Therefore, CAN should not be evaluated by product name alone. Buyers should confirm the actual contents of total nitrogen, nitrate nitrogen, ammonium nitrogen, and calcium.

Key Characteristics

• Contains both nitrate nitrogen and ammonium nitrogen.

• Combines rapid nitrogen availability with more sustained nitrogen nutrition.

• Commonly supplied in granular form.

• Generally offers better handling, storage, and mechanical application properties than crystalline calcium nitrate.

• Particularly suitable for field crops, orchards, and large-scale soil fertilization.

CAN is widely used on wheat, maize, oilseed rape, potatoes, vegetables, and fruit crops.

3. Key Differences Between CNT and CAN

Parameter	Calcium Nitrate Tetrahydrate (CNT)	Calcium Ammonium Nitrate (CAN)
Product nature	Defined crystalline compound	Compound/blended nitrogen-calcium fertilizer
Typical form	White crystals	Granules
Main nitrogen form	Nitrate nitrogen	Nitrate + ammonium nitrogen
Nitrogen availability	Rapid	Rapid + sustained
Calcium supply	Highly water-soluble calcium	Depends on formulation
Water solubility	High	Varies by grade
Hygroscopicity	Relatively high	Generally better suited to bulk storage
Main application	Fertigation, hydroponics, nutrient solutions	Basal and top-dressing applications
Typical market	Intensive and high-value crops	Field crops and large-scale farming

The essential difference can be summarized simply:

CNT focuses on high solubility and rapid calcium delivery, while CAN focuses on combined nitrogen-calcium nutrition and efficient field application.

4. How to Choose for Agricultural Use

High-Value Crops and Protected Agriculture — CNT

For tomatoes, peppers, cucumbers, grapes, citrus, strawberries, and other high-value crops, particularly under fertigation, hydroponics, or greenhouse production, CNT offers clear advantages.

Its high solubility allows it to enter nutrient solutions quickly and supply both nitrate nitrogen and readily available calcium.

Typical applications include:

• Drip irrigation and fertigation

• Hydroponic nutrient solutions

• Calcium supplementation during fruit development

• High-grade water-soluble fertilizer production

• Calcium and calcium-magnesium fertilizer formulations

One important formulation consideration is that concentrated calcium nitrate solutions should generally not be stored together with high concentrations of phosphates or sulfates, as insoluble calcium salts may form and potentially cause precipitation or irrigation-system blockage.

Field Crops and Large-Scale Fertilization — CAN

Field crops such as wheat, maize, oilseed rape, and potatoes generally require larger nitrogen inputs and benefit from fertilizers with good granule strength and mechanical application performance.

Because CAN contains both nitrate and ammonium nitrogen, it provides an immediate nitrogen response while maintaining a degree of continued nitrogen availability.

Its granular form makes it particularly suitable for:

• Basal fertilization

• Top dressing

• Band application

• Broadcasting

• Mechanized field application

5. CAN Is Not a Single Standard Grade

Commercial CAN products vary significantly, which is particularly important in international sourcing and fertilizer trade.

Low-Nitrogen, High-Calcium Grades

For example:

N 15.5% + approximately 26% CaO

These grades emphasize calcium nutrition and are more suitable for specialty fertilizers and certain water-soluble fertilizer systems.

High-Nitrogen Grades

For example:

N 26–27%

These products are positioned primarily as nitrogen fertilizers for field crops and top-dressing applications.

CAN can also be further formulated into products such as:

• CAN + Boron 

• CAN + Magnesium 

• CAN + Sulfur 

• CAN + Trace Elements 

These formulations allow nutrient programs to be adapted to different crops and soil conditions.

6. CNT and CAN Serve Different Market Positions

Although both products supply calcium and nitrogen, they should not be viewed simply as substitutes for one another.

CNT is better positioned as a specialty, highly water-soluble calcium-nitrogen source.

Its main advantages are purity, solubility, and rapid calcium availability, making it particularly suitable for fertigation, hydroponics, intensive agriculture, and high-value crops.

CAN is better positioned as a large-scale granular nitrogen-calcium fertilizer.

Its strengths lie in combined nitrogen nutrition, granular handling properties, and efficient application across broadacre farming systems.

The correct choice therefore depends not on which product is inherently “better,” but on the crop, application system, soil conditions, and target nutrient profile.

Conclusion

From protected horticulture to broadacre farming, combined calcium and nitrogen nutrition is becoming increasingly important in modern fertilizer programs.

Calcium Nitrate Tetrahydrate stands out for its high solubility and rapid calcium availability, while Calcium Ammonium Nitrate offers the advantages of combined nitrate and ammonium nitrogen, granular handling, and efficient large-scale field application.

Understanding these differences allows growers, formulators, and fertilizer buyers to select the most appropriate calcium-nitrogen source for more precise and efficient crop nutrition.

Calcium Nitrate Tetrahydrate (CNT) vs. Calcium Ammonium Nitrate (CAN): Two Key Calcium-Nitrogen Fertilizers