Next-Gen Phosphate: Urea Phosphate for Sustainable Agriculture and Feed Additive

In the context of modern agriculture's growing focus on efficient fertilization and precision management, fertilizer raw materials with high water solubility, compound nutrients, and acidity adjustment capacity have gained increasing attention. Urea phosphate, a binary nitrogen-phosphorus compound, not only demonstrates excellent performance in drip irrigation systems and water-soluble fertilizer formulations but is also widely favored in global protected agriculture and high-end fruit and vegetable production for its ability to amend alkaline soils.

This article offers an in-depth introduction to the fundamental properties, production process, and key application areas of urea phosphate. It also compares its performance and complementarity with common phosphate fertilizers such as MAP(Monoammonium Phosphate), analyzes its suitability in fertigation and integrated water-fertilizer systems, and provides a systematic examination of biuret control technologies, global market dynamics, and development trends—helping readers gain a comprehensive understanding of this functional and high-potential fertilizer raw material.

Basic Information and Physicochemical Properties of Urea Phosphate

Item	Specification / Description
Chemical Name	Urea Phosphate
Molecular Formula	CO(NH₂)₂·H₃PO₄
CAS Number	4861-19-2 / 4401-74-5
Molecular Weight	158.06 g/mol
Appearance	White or colorless crystals
Nitrogen Content (N)	≥17–18%
Phosphorus Content (P₂O₅)	≥44%
Water Solubility	Highly soluble in water (>1000 g/L)
Solution pH (1%)	1.6–2.0 (strongly acidic)
Relative Density (20°C)	1.62
Melting Point	Dehydrates before decomposing at approximately 120°C
Biuret Content	≤0.9% (customizable to ≤0.5%)
Stability	Stable under normal temperature and pressure, moderately hygroscopic
Compatibility	Compatible with most water-soluble fertilizers

Overview of the Production Process

The production of urea phosphate primarily relies on a neutralization reaction between urea and phosphoric acid. The process is straightforward, raw materials are readily available, and product quality is controllable—making it suitable for fertilizer enterprises with access to urea and phosphoric acid to extend their product chains.

1. Main Chemical Reaction:

CO(NH₂)₂ + H₃PO₄ → CO(NH₂)₂·H₃PO₄

This is an exothermic reaction. By controlling the raw material ratio, reaction temperature, stirring speed, and crystallization conditions, high-purity urea phosphate can be efficiently produced.

2. Simplified Process Flow:

• Raw Material Pretreatment: Use low-biuret urea and filtered phosphoric acid;

  
  

• Reaction Phase: Conduct the neutralization reaction at a controlled temperature of 70–90°C;

  
  

• Crystallization and Cooling: Lower the temperature to induce crystallization of urea phosphate (UP);

  
  

• Solid–Liquid Separation: Separate crystals via centrifugation or filtration;

  
  

• Drying and Packaging: Dry with hot air, then screen and bag the product.

  
  

3. Key Process Control Points:

Control Stage	Key Considerations
Raw Material Selection	Biuret content in urea should be below 1%; phosphoric acid must be filtered to remove impurities
Temperature Control	Reaction temperature should not be too high to avoid excessive biuret formation
Molar Ratio Control	A molar ratio close to 1:1 is recommended to ensure complete reaction
Crystallization Control	Proper cooling is essential to prevent coarse crystals or pipeline blockage
Mother Liquor Utilization	Recyclable for reuse to enhance production efficiency

Biuret’s Impact on Product Quality

In practical applications of urea phosphate, biuret—a seemingly minor by-product—is a critical indicator of both product quality and agronomic safety. Its content directly determines whether the product is suitable for high-end water-soluble fertilizers and foliar spray systems, and whether it can meet the stringent safety requirements of international markets.

1. Introduction to Biuret and Its Harmful Effects

Biuret is a by-product formed when urea undergoes condensation reactions at high temperatures or during prolonged storage. Excessive biuret content can be toxic to plants, particularly to leaf tissues.

• May cause leaf burn, chlorosis, and tip necrosis;

  
  

• Young seedlings and sensitive crops (e.g., tomatoes, grapes, citrus) are more vulnerable;

  
  

• Particularly hazardous in crops that rely on high-frequency fertilization such as foliar spray, drip irrigation, or root flushing.

  
  

2. International Market Standards

Region / Market	Biuret Limit	Application Background
Europe	≤0.5%	High-end liquid fertilizers and foliar application products
Middle East / Israel	≤0.7%	Strict safety standards for drip irrigation systems
Asia / General Market	≤0.9%	Suitable for general water-soluble fertilizer formulations
High-end Custom Standards	≤0.3–0.5%	Export-grade fertilizers, certified crops

3. Risk Analysis

As biuret content increases, crop risk index rises nonlinearly. Risks escalate sharply beyond 0.9%, and the ideal safety threshold is ≤0.5%.

Key Application Areas

Urea phosphate (UP) is a typical multifunctional nutrient material widely used in agriculture, feed, horticulture, water-soluble fertilizer manufacturing, water treatment, and select pharmaceutical applications. Unlike traditional phosphate fertilizers that merely supply phosphorus, UP combines nitrogen supply, pH regulation, system compatibility, and formulation stability, making it a versatile component across multiple domains.

4.1 Agricultural Applications

1. Crop Cultivation

• Target Crops: Blueberries, citrus fruits, grapes, tomatoes, peppers, melons, flowers, seedlings, and other sensitive-root crops;

  
  

• Soil Suitability: Neutral to alkaline soils, hard water irrigation zones, protected agriculture, and areas with limited micronutrient availability;

  
  

Application Methods:

• Drip Irrigation Fertilization:

  Recommended concentration: 0.05–0.3%; continuously applied in fertigation systems to reduce Ca/Mg scaling risks.

  
  

• Micro-spray / Spray Fertigation:

  Periodic flushing recommended, combined with micronutrients or potassium-based water-soluble fertilizers.

  
  

• Foliar Spray:

  Diluted to 0.1–0.2% and applied during phosphorus deficiency or critical seedling development stages.

  
  

• Root Zone Application:

  2–5 kg/mu (≈13–33 kg/ha) per application; ideal during budding or fruit expansion in orchards.

  
  

2. Water-Soluble Fertilizer Formulation

• Highly compatible with potassium nitrate, mono-potassium phosphate, chelated micronutrients, etc.;

  
  

• Functions as both a nutrient supplier and pH regulator in clear liquid and tank-mix fertilizers;

  
  

• Suggested dosage: 50–200 kg per ton of mother solution, depending on formulation needs.

  
  

3. Comparison with Monoammonium Phosphate (MAP)

Comparison Item	Urea Phosphate (UP)	MAP (Monoammonium Phosphate)
Nitrogen Form	Urea-N + Phosphorus	Ammonium-N + Phosphorus
Solution Acidity	Strongly acidic (pH ≈ 1.6–2.0), excellent acidifying	Mildly acidic (pH ≈ 4.5), weaker pH regulation
System Compatibility	Non-scaling, ideal for drip systems and hard water	Prone to Ca/Mg scaling and emitter clogging
Micronutrient Synergy	Strong (low pH improves Fe/Zn/Mn uptake)	Moderate
Cost-Effectiveness	Slightly higher cost but more efficient, suited for high-value crops	Moderate price-to-performance, suited for broad-acre farming

➡ UP is better suited for precision fertilization and integrated fertigation, serving as an upgrade over MAP in modern irrigation-based systems.

4. Feed-Grade Applications of Urea Phosphate

In addition to plant nutrition, feed-grade urea phosphate serves as a phosphorus and nitrogen additive in livestock diets, particularly in phosphorus-deficient or alkaline water environments:

• Dual Nutrient Supply:

  Provides highly available phosphorus (as P₂O₅) and non-protein nitrogen (from urea), improving rumen microbial activity and feed conversion efficiency.

  
  

• Acidification Effect:

  Its strong acidity helps lower the pH of drinking water or feed, reducing harmful gut bacteria and enhancing nutrient absorption.

  
  

• Mineral Absorption Enhancement:

  Acidified feed promotes better uptake of trace minerals like zinc, iron, and manganese.

  
  

• Typical Application:

  Suitable for dairy and beef cattle, sheep, and goats. Usually added in premix form or as water-soluble supplements according to controlled dosage schemes.

  
  

Standard Reference – Feed Grade Urea Phosphate Composition

Component	Specification	Remarks
Nitrogen (N)	≥ 17.0%	Non-protein nitrogen source
Phosphorus (P)	≥ 19.0%	Promotes bone development
Potassium (K)	Not required (0%)	Naturally absent in urea phosphate
Biuret	≤ 0.5%	Controlled for animal safety

⚠ Note: Feed-grade UP requires stricter control of heavy metals and biuret levels (≤ 0.5%) to comply with feed hygiene regulations and ensure animal safety.

4.2 Industrial Applications

Urea phosphate also plays a significant role in several industrial sectors, leveraging its solubility, acidity, and phosphorus content.

1. Water Treatment

• Used in boiler and closed-loop cooling systems as an acidic phosphate source to reduce calcium/magnesium scaling;

  
  

• Functions as a chelating and anti-scaling agent, protecting metal surfaces from deposits.

  
  

2. Metal Cleaning and Surface Treatment

• Added to acidic detergent formulations for metal surface degreasing, de-rusting, and descaling;

  
  

• Effective as a component in pre-treatment baths for coating or passivation processes;

  
  

• Combines mild corrosion inhibition with phosphorus-driven complexing ability.

  
  

3. Semiconductor and Electronics Cleaning (High-Purity Grade)

• In ultra-low impurity form, it may be used for wafer surface cleaning in the electronics industry.

  
  

• Provides controlled acidity without introducing chlorine or reactive metal ions.

  
  

4. Resin and Flame Retardant Industry

• May serve as a pH regulator or co-curing agent in the production of certain epoxy or phenolic resins;

  
  

• Can also be used in phosphate-based fire retardant systems, especially in coatings and construction materials.

4.3 Pharmaceutical and Veterinary Applications

Although still limited to niche or research contexts, urea phosphate has potential uses in pharma and veterinary domains, particularly in its ultra-pure forms:

1. Pharmaceutical Applications

• May be used as a buffering agent in ophthalmic or injectable solutions where acidic pH is desired;

  
  

• Its solubility and phosphorus content make it a candidate for nutrient-delivery excipients in special formulations.

  
  

2. Veterinary Medicine

• Applied in oral solutions or powders to address mineral deficiencies or to acidify urine;

  
  

• In poultry and swine, it supports urinary pH control, reducing the risk of urinary calculi.

  
  

⚠ Pharmaceutical use requires extreme purity standards—biuret content typically <0.3%, and heavy metals at pharmaceutical-grade thresholds. Applications remain highly regulated and are often limited to specialized production lines.

Application Methods and Precautions

Urea phosphate offers diverse application methods in agriculture, fitting a variety of crops and management systems—especially well-suited for modern fertigation through drip and micro-spray irrigation systems. Application should be flexibly adjusted based on crop type, growth stage, and environmental conditions.

1. Recommended Application Methods and Reference Concentrations

Application Method	Concentration / Dosage	Notes
Drip Irrigation Fertilization	0.05% – 0.3%	Highly soluble, non-clogging; ideal for continuous delivery through standard pipelines
Micro-spray / Spray Irrigation	0.1% – 0.2%	Suitable for high-value crops and protected agriculture
Root Zone Flushing	2–5 kg/mu (≈13–33 kg/ha)	Ensure thorough dilution; apply during critical growth stages
Foliar Spray	0.1% – 0.2% solution	For quick phosphorus supplementation during seedling stage or flower bud initiation; avoid spraying at midday heat
Water-soluble Fertilizer Formulations	50–200 kg/ton of mother solution	Fits most formulations; functions as primary phosphorus source and pH regulator

2. Mixing Compatibility Recommendations

• Compatible with: Potassium nitrate, mono-potassium phosphate, magnesium sulfate, chelated micronutrients, etc.

  
  

• Avoid mixing with: Strongly alkaline fertilizers (e.g., potassium carbonate), calcium/magnesium-based fertilizers (prone to scaling), free ammonia-type raw materials;

  
  

• Suggested mixing sequence: Dissolve UP first, then add other nutrients; avoid mixing concentrated solutions directly to prevent precipitation.

  
  

3. Storage, Transport, and Safety

• Packaging Suggestions: Sealed and moisture-proof;

  
  

• Storage Conditions: Store in a dry, ventilated place; avoid moisture absorption and caking;

  
  

• Transport Classification: Non-hazardous product; can be handled as regular chemical fertilizer during transport.

Market Landscape and Driving Factors

With the upgrading of the water-soluble fertilizer market, the expansion of irrigation agriculture, and growing demand for high-end horticulture, the global market share of urea phosphate (UP) continues to rise. Its role is increasing rapidly, especially in regions like the Middle East, South Asia, Mediterranean countries, and nations with developed protected agriculture systems.

1. Regional Market Characteristics

Region	Market Status and Preferences
China	Widely used in protected agriculture and fruit/vegetable cultivation; high market acceptance
India / South Asia	Emerging drip irrigation systems; high penetration in tomatoes, peppers, grapes
Middle East / Israel	Mature drip irrigation systems; UP is a designated phosphate source for high-value crops like grapes, dates, and melons
Europe	Premium market requiring high quality and low biuret; commonly used in greenhouse vegetables and organic horticulture
South America	Gradually introduced in countries like Brazil and Chile; great potential

2. Market Development Drivers

• Fertigation Popularization → Rising demand for highly soluble and anti-scaling fertilizers; UP is growing rapidly;

  
  

• Widespread Soil pH Issues → Need for alkaline soil correction increases; UP has a natural advantage;

  
  

• Upgraded Agricultural Inputs → More refined fertilizer formulations; UP aids in acidification and micronutrient stabilization;

  
  

• MAP Substitution Progress → UP outperforms in compatibility, safety, and synergistic nutrient absorption.

  
  

3. Market Trends and Structural Evolution

• From Single-Source Phosphate to Functional Phosphorus:

  UP is transitioning from being solely a phosphorus provider to a multifunctional component that offers both acidification and nutrient delivery.

  
  

• From Commodity to Branded & Quality Products:

  The market is shifting toward branded, premium-grade urea phosphate products, moving beyond generic bulk materials.

  
  

• From Solid to Liquid Applications:

  Urea phosphate is increasingly used in liquid formats such as clear liquid fertilizers and tank-mix systems.

  
  

• From Price Competition to Quality Stability & Brand Trust:

  Competitive advantages are evolving toward product stability, biuret control, and strong brand credentials instead of just pricing.

Product Specifications of Urea Phosphate

Depending on application areas and quality standards, urea phosphate is generally categorized into the following types:

Category Type	Key Characteristics and Application Areas
Standard Grade UP	Used in agriculture; biuret ≤0.9%; suitable for water-soluble fertilizer production and drip irrigation systems
Low-Biuret Grade	Biuret controlled to ≤0.5%; suitable for foliar application or export liquid fertilizers with higher safety requirements
High-Purity Special Grade	Biuret ≤0.3%; heavy metals strictly controlled; suitable for horticulture or certified organic farming
Industrial / Cleaning Grade	Used in non-agricultural fields such as water treatment, metal cleaning, and boiler corrosion inhibition

Urea phosphate is a highly efficient water-soluble fertilizer raw material that provides both nitrogen and phosphorus while regulating acidity. It plays an increasingly important role in modern agriculture, especially in drip irrigation, horticulture, and integrated fertigation systems. With its high solubility, anti-scaling nature, and ability to enhance micronutrient absorption, UP is gradually replacing traditional MAP in high-end irrigation fertilization and becoming a key base material for new-generation clear liquid and tank-mix fertilizers.

In practical application, biuret content is a critical index affecting the agronomic safety and market access of urea phosphate. Currently, Kelewell only supplies “Standard Grade Urea Phosphate”, which ensures long-term and stable availability to meet the mainstream needs of water-soluble fertilizer plants, export traders, and agricultural growers.

We welcome global customers to engage in cooperation and technical exchange regarding urea phosphate products.For inquiries or technical requirements, please feel free to contact us via: info@kelewell.de