How do you use water-soluble fertilizer?

1. Foliar application or drip irrigation
Before flushing application, dilute the fertilizer by dissolving it in water, then apply it with irrigation water. Some growers directly sprinkle powdered microbial inoculants into water due to their rapid dissolution. By the time the solution reaches the root zone, it is fully diluted. While this method is simpler, it is only suitable for small plots. It is not recommended for large-scale fertilization of orchards or fields. Some growers also pour diluted fertilizer into a bucket and apply it via hose irrigation or drip irrigation.
2. Injection Application
This method also requires prior dilution. The solution is poured into a bucket and injected near the root zone using a fertilizer injection gun. It is commonly used for fruit trees with deep root systems. For example, fruit growers often employ injection application when using rooting agents, as it is simple and effective.
3. Foliar Application
Similarly, dilute first. For example, when applying potassium dihydrogen phosphate, pour it into a bucket, ensuring the specified dilution ratio is followed. After dilution, transfer it to a sprayer for application. This method is suitable for all types of crops. For instance, when applying potassium dihydrogen phosphate that dissolves in 5 seconds and is absorbed in 5 minutes to rice, foliar application is often used for its rapid effect and simplicity.
4. Broadcast Application
Granular water-soluble fertilizers are typically applied by broadcasting—simply scatter them without dissolving.
5. Trench Application
Dig trenches or form circular mounds around the root zone of fruit trees, ensuring roots remain covered. Pour the dissolved fertilizer solution into these trenches or mounds.
6. Basal Application
This refers to applying fertilizer as a base dressing. First, add a layer of coarse sandy soil to the soil, then evenly spread the fertilizer, and cover with another layer of soil. This prevents direct contact between the fertilizer and the roots, avoiding root burn. Some growers also mix the fertilizer into the soil when applying it as a base dressing.
Sister Zhang, a tomato grower in Inner Mongolia, often encountered difficulties due to improper application of water-soluble fertilizers, resulting in poor seedling establishment. After receiving guidance from a technical instructor on correct drip irrigation techniques, her crops finally showed improvement. This underscores the critical importance of proper water-soluble fertilizer application—especially when using lower-quality products—where meticulous methods are essential to maximize overall effectiveness.

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