In agricultural production, chemical products such as urea, diammonium phosphate (DAP), potassium chloride, potassium sulfate, and compound fertilizers are commonly used as fertilizers. They have high nutrient content and take effect quickly; choosing the right ones can significantly improve crop yield and quality. However, blind selection not only wastes costs but may also lead to soil compaction and crop root burn. The key lies in precise selection based on two core dimensions: "soil needs and crop characteristics".
First, consider soil adaptation: Test the soil before selecting fertilizers to avoid "blind application". For slightly acidic soil (pH < 6.5), prioritize alkaline chemical fertilizers such as calcium magnesium phosphate fertilizer and ammonium bicarbonate, which can both supplement nutrients and neutralize acidity. For alkaline soil (pH > 7.5), choose acidic fertilizers like ammonium sulfate and superphosphate to reduce the impact of salinization. If the soil is deficient in nitrogen (characterized by yellowing leaves), urea (with 46% nitrogen content, the highest among chemical fertilizers) is the first choice, and it is highly effective for both broadcasting and fertigation. For phosphorus deficiency (weak root systems and low fruit set), select diammonium phosphate (containing 46% phosphorus and 18% nitrogen), which is suitable for promoting root growth in the seedling stage of crops.
Next, consider crop needs: Different crops and different growth stages have vastly different requirements for chemical fertilizers. Leafy vegetables (such as spinach and lettuce) require high nitrogen throughout their growth cycle; urea can be the main fertilizer, top-dressed 2-3 times during the growth period, with 15 kg per mu each time to promote thick, lush leaves. For fruiting vegetables (such as tomatoes and cucumbers), high potassium is needed after fruit set; choose potassium sulfate-based compound fertilizers (with an N-P-K ratio of 15:15:20), applying 20 kg per mu each time to enhance fruit sweetness and luster. For field crops (such as wheat and corn), coordinated nitrogen and phosphorus are required during the tillering/jointing stage; use a mixture of diammonium phosphate and urea.
Choosing the right fertilizer not only saves money but also promotes healthy crop growth, achieving "precision fertilization and efficient yield increase".