1、Urea Transformations and Fertilizer Efficiency in Soil

Much of the urea in the United States is applied as urea ammonium nitrate solution prepared by combination of urea with ammonium nitrate. Although urea is frequently equivalent to other nitrogenous fertilizers poor crop responses to urea have frequently been observed.

2、Urea: A Low Cost Nitrogen Fertilizer with Special Management R

In common with most commercial nitrogen fertilizers, urea is manufactured from anhydrous ammonia (NH 3 ). The high analysis of urea—46% N—is the main reason for the low cost of this form of nitrogen fertilizer.

3、Urea Fertilizer: The Global Challenges and Their Impact to Our Sustainability

Considering the adverse effects of conventional fertilizers, the Green Urea is proposed as new nitrogen-based enhanced efficiency fertilizer (EEF) production and utilization, where a novel integrated ammonia–urea process and product was proposed.

Nitrogen transformations in modern agriculture and the role of biological nitrification inhibition

Ammonium-based fertilizers (urea, anhydrous NH 3, (NH 4) 2 SO 4 and NH 4 NO 3) comprise the most commonly used forms of N applied in agriculture 27.

Environmentally Friendly Slow

The release profiles of urea, ammonium sulfate, and ammonium chloride as nitrogen fertilizer substrates were determined in soil. To further compare the release profiles of nitrogen from different fertilizer substrates, a mathematical model for nutrient release from the coated fertilizer was applied to calculate the diffusion coefficient D.

Slow release coating remedy for nitrogen loss from conventional urea: a review

Owing to higher nitrogen content, urea supplies more nitrogen per ton of applied solids as compared to other nitrogenous fertilizers. The past research efforts have remained unsuccessful in producing a conventional urea based fertilizer with a prolonged release of nitrogen.

Nitrogen Dynamics in Soil Fertilized with Slow Release Brown Coal

A novel fertilizer material that was formed by blending brown coal (BC) with urea, delayed fertilizer N release in controlled climatic conditions in a glasshouse, through strong retention...

Comparison of yield and nitrogen use efficiency of different types of nitrogen fertilizers for different rice cropping systems under subtropical monsoon

Controlled release urea (CRU) and urea with nitrification inhibitor could improve yields and nitrogen use efficiency (NUE) in a number of production systems. However, their effectiveness will be strongly influenced by environmental conditions.

Cumulative release characteristics of controlled

Soil inorganic nitrogen contents significantly increased by using PCU instead of urea, and the same trend was observed with soil available potassium contents, which also had increased rates.

Urea contributions to dissolved ‘organic’ nitrogen losses from intensive, fertilised agriculture

Urea (CO (NH 2) 2) presents a somewhat special form of dissolved ‘organic’ nitrogen, as it can be derived from both natural and anthropogenic processes.

Urea is a common type of nitrogen fertilizer synthesized through the chemical reaction of ammonia (NH₃) and carbon dioxide (CO₂). Widely used in agriculture, it enhances crop yields and improves soil quality. Below is a detailed explanation of urea:

I. Chemical Composition of Urea

1. Molecular Structure

• The chemical formula of urea is CH₄N₂O, composed of carbon, hydrogen, nitrogen, and oxygen. Its basic structure features a cyclic arrangement where one nitrogen atom bonds to two carbon atoms and one oxygen atom.

2. Key Properties

• Urea appears as white crystals with hygroscopicity and volatility. It dissolves in water but has low solubility. Over time, it decomposes in air, releasing ammonia (NH₃) and carbon dioxide (CO₂).

II. Applications of Urea in Agriculture

1. Promoting Plant Growth

• Nitrogen in urea is essential for plant development. After application, it converts into nitrate or ammonium ions in the soil, which plants absorb to support growth and photosynthesis.

2. Improving Crop Yields

• Urea significantly boosts crop biomass and yield by providing readily available nitrogen for photosynthesis. It can also be combined with other fertilizers for enhanced results.

3. Enhancing Soil Quality

• Urea increases soil organic matter, improving its structure, water retention, and aeration. Additionally, it suppresses weed growth, reducing competition for crops.

4. Environmental Considerations

• While excessive urea use may harm the environment, proper management—such as adjusted application rates, organic fertilizer substitution, and timing—can mitigate negative impacts like nitrogen runoff.

III. Usage and Precautions

1. Application Methods

• Urea is typically applied as solid granules. Dissolve in water to form a solution before use. Dosage depends on soil type, crop, and growth stage, averaging 5–10 kg per mu.

2. Safety Notes

• Avoid overapplication to prevent waste and pollution.
• Do not mix with alkaline substances (reduces efficacy).
• Avoid skin/eye contact; flush immediately if exposed.
• Store away from high temperatures to prevent fire hazards.

IV. Comparing Urea With Other Fertilizzers

1. Versus Other Nitrogen Fertilizers

• Urea is cost-effective and easy to use but acts slower than alternatives like ammonium bicarbonate or ammonium nitrate. Its delayed efficacy requires patience for optimal results.

2. Versus Organic Fertilizers

• As a synthetic fertilizer, urea provides stable, rapid nitrogen release but is less sustainable and more expensive than organic options. Organic fertilizers, derived from natural matter, offer slower, holistic nutrient delivery.

Urea is a vital nitrogen fertilizer critical to agricultural productivity. By combining it with other fertilizers and adopting eco-friendly practices, farmers can maximize crop yields while preserving soil health and environmental sustainability.