What is the correct way to use organic fertilizer, compound fertilizer, and urea?

Anyone who grows crops knows that fertilizers are essential for both planting and maintenance. Only with adequate nutrients and water can crops thrive. Commonly used fertilizers include organic fertilizers, compound fertilizers, and urea. However, some novice vegetable growers and inexperienced farmers use a lot of fertilizer without seeing good results. Many people don’t know how to use organic fertilizer, compound fertilizer, and urea most effectively. Today, I’d like to discuss this topic and share the best application methods with you.
Organic Fertilizer
Organic fertilizer is commonly used for vegetable cultivation. Because it releases nutrients slowly and has a long-lasting effect, it is primarily used as a base fertilizer, though it can also be applied as a top-dressing.
Base Fertilizer
There are two methods for applying base fertilizer. The first involves mixing the fertilizer into the soil. Before tilling, spread the organic fertilizer over the soil surface, then incorporate it into the soil while tilling. This method is best suited for growers with an abundant supply of organic fertilizer and works best for loose soil, helping to enrich and improve soil quality. The second method is for situations where organic fertilizer is scarce or insufficient. In this case, you can apply the fertilizer by digging a trench and spreading it inside, then covering it with at least 5 centimeters of soil. Plant or transplant the crops on top of this layer. This approach prevents root and seed burn, allows the root system to absorb the sheep manure, and minimizes waste.
Top Dressing
For top dressing with organic fertilizer, you can use either solid fertilizer or liquid manure. The best method is to dig a hole or trench about 8–10 centimeters away from the plant’s base, apply the fertilizer, and then cover it with soil. This approach prevents environmental pollution, avoids attracting pests, and prevents root burn. Organic fertilizers generally should not be applied via irrigation, as this leaves much of the fertilizer exposed on the surface, which not only attracts pests and ants but is also unsanitary. Additionally, fertilizer should not be placed too close to the root system, as this can easily cause root burn.
Compound Fertilizer
Compound fertilizer can be used as a base fertilizer or as a top-dressing and is suitable for any crop.
Basal Fertilizer
Compound fertilizers have a long-lasting effect and are often used as basal fertilizers. Mixing them with organic fertilizers as basal fertilizer yields even better results. Since compound fertilizers are prone to volatilization, they must be applied deeply. They can be applied in trenches or holes during planting. Whether applying in trenches or holes, the fertilizer must be kept separate from the seeds and roots; it must not come into contact with them. Soil should be used to create a barrier between the fertilizer and the seeds to prevent seed and root burn. Since there are many types of compound fertilizers, select the appropriate one based on the specific crop variety. For example, choose a high-nitrogen compound fertilizer for nitrogen-demanding crops, and a high-potassium compound fertilizer for potassium-loving crops, and so on.
Top Dressing
Compound fertilizers are generally used as base fertilizers; their utilization rate as top dressings is not high. Not only is the effect poor, but they also volatilize easily, leading to waste. If you wish to use compound fertilizer for top dressing, do not broadcast it on the surface. Instead, dig a hole slightly away from the roots and bury it deeply, or dilute it 200–300 times with water and apply it as a drench. However, compound fertilizers are generally not recommended for top dressing.
Urea
Urea is the nitrogen fertilizer with the highest nitrogen content, but it is not suitable as a base fertilizer; instead, it is best used as a top-dressing. There are two methods for applying urea as a top-dressing: one is burial, and the other is dilution and irrigation.
Burying
When using urea as a top-dressing, it is generally buried in a hole. This involves digging a hole or trench about 10 centimeters away from the roots, placing the fertilizer inside, and covering it with soil. Because urea dissolves quickly, spreading it on the soil surface can easily cause the fertilizer to volatilize, resulting not only in low utilization but also in waste.
Irrigation
Urea is a fast-acting fertilizer. When applying as a top-dressing, it can be dissolved in water and applied via irrigation; however, the concentration must not be too high. Generally, the dilution ratio ranges from 200 to 300 times the amount of water, depending on the size of the seedlings. Additionally, urea can be mixed with water and sprayed onto leaves, but the dilution ratio for foliar application must be at least 500 times. It can also be mixed with other fertilizers for use.