Ammonium Phosphate vs. Urea Phosphate

What's the Difference?

Ammonium Phosphate and Urea Phosphate are both commonly used fertilizers in agriculture. However, they differ in their chemical composition and nutrient content. Ammonium Phosphate is a compound that contains both ammonium and phosphate ions, providing a balanced supply of nitrogen and phosphorus to plants. On the other hand, Urea Phosphate is a compound that combines urea and phosphate, offering a source of nitrogen and phosphorus as well. While Ammonium Phosphate is known for its quick-release properties, Urea Phosphate is considered a slow-release fertilizer, providing a longer-lasting nutrient supply to plants. Ultimately, the choice between these fertilizers depends on the specific needs of the crops and the desired release rate of nutrients.


AttributeAmmonium PhosphateUrea Phosphate
Chemical Formula(NH4)3PO4(NH2)2CO·H3PO4
AppearanceWhite crystalline solidWhite crystalline solid
SolubilityHighly soluble in waterHighly soluble in water
UsageFertilizer, flame retardantFertilizer, flame retardant
Nitrogen ContentContains nitrogenContains nitrogen
Phosphorus ContentContains phosphorusContains phosphorus
Ammonium ContentContains ammonium ionsDoes not contain ammonium ions
Urea ContentDoes not contain ureaContains urea

Further Detail


Ammonium phosphate and urea phosphate are two commonly used fertilizers in agriculture. Both compounds provide essential nutrients to plants, promoting healthy growth and increased crop yields. While they share similarities in terms of their nutrient content, there are also distinct differences between the two. In this article, we will explore the attributes of ammonium phosphate and urea phosphate, highlighting their composition, benefits, and applications.


Ammonium phosphate is a compound that contains both nitrogen and phosphorus. It is typically produced by reacting ammonia with phosphoric acid. The resulting product can have different ratios of nitrogen to phosphorus, such as monoammonium phosphate (MAP) with a 1:1 ratio or diammonium phosphate (DAP) with a 2:1 ratio. On the other hand, urea phosphate is a compound composed of urea and phosphoric acid. It contains nitrogen, phosphorus, and carbon, making it a more complex fertilizer compared to ammonium phosphate.

Nutrient Release

One of the key differences between ammonium phosphate and urea phosphate lies in their nutrient release patterns. Ammonium phosphate, particularly MAP and DAP, releases nitrogen and phosphorus gradually over time. This slow-release characteristic allows for sustained nutrient availability to plants, reducing the risk of nutrient leaching and ensuring efficient uptake. In contrast, urea phosphate releases its nutrients more rapidly, providing an immediate boost to plant growth. However, this fast-release nature can also lead to nutrient loss if not managed properly.

Acidic vs. Alkaline Soil

Another factor to consider when comparing ammonium phosphate and urea phosphate is their impact on soil pH. Ammonium phosphate tends to have an acidic effect on soil due to the presence of ammonium ions. This can be beneficial for crops that thrive in acidic conditions, such as blueberries or rhododendrons. On the other hand, urea phosphate has a neutral pH, making it suitable for crops that prefer a more alkaline soil environment. Understanding the pH requirements of different plants is crucial in selecting the appropriate fertilizer.

Plant Uptake Efficiency

When it comes to nutrient uptake efficiency, both ammonium phosphate and urea phosphate have their advantages. Ammonium phosphate, being a source of ammonium nitrogen, is readily absorbed by plants. Ammonium nitrogen is positively charged, allowing it to bind to negatively charged soil particles and remain available for plant uptake. Additionally, the presence of phosphorus in ammonium phosphate enhances root development and overall plant growth. Urea phosphate, on the other hand, provides a quick supply of nitrogen in the form of urea. Urea is converted into ammonium in the soil through a process called hydrolysis, making it available for plant uptake. However, urea phosphate may require additional steps for phosphorus to become accessible to plants.

Application Methods

Ammonium phosphate and urea phosphate can be applied using various methods depending on the specific needs of the crops and soil conditions. Both fertilizers can be broadcasted, meaning they are spread evenly across the soil surface. This method is commonly used for large-scale farming operations. Alternatively, they can be applied through banding, where the fertilizer is placed in a concentrated band near the plant roots. This method allows for more targeted nutrient delivery and is often used in row crops. Additionally, ammonium phosphate and urea phosphate can be applied as a foliar spray, where the fertilizer is dissolved in water and sprayed directly onto the leaves. This method provides a quick nutrient boost and is particularly useful in correcting nutrient deficiencies.

Environmental Considerations

When comparing the environmental impact of ammonium phosphate and urea phosphate, several factors come into play. Both fertilizers have the potential to contribute to nutrient runoff and water pollution if not managed properly. However, due to its slow-release nature, ammonium phosphate has a lower risk of leaching compared to urea phosphate. The rapid release of nitrogen in urea phosphate can lead to excess nutrients entering water bodies, causing eutrophication and harming aquatic ecosystems. To mitigate these risks, proper application techniques, timing, and nutrient management practices should be implemented.


In conclusion, ammonium phosphate and urea phosphate are two fertilizers commonly used in agriculture. While they both provide essential nutrients to plants, they differ in terms of composition, nutrient release patterns, impact on soil pH, plant uptake efficiency, and application methods. Understanding these attributes is crucial in selecting the most suitable fertilizer for specific crops and soil conditions. By considering factors such as nutrient requirements, soil pH, and environmental considerations, farmers can make informed decisions to optimize plant growth and minimize environmental impact.

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