First, it's important to deepen the fertilizer application. Many vegetable farmers have the habit of watering while applying chemical fertilizers. However, this method is not scientifically sound, especially during hot summer days. Under high temperatures, nitrogen-based fertilizers such as urea, ammonium nitrate, and ammonium bicarbonate tend to break down quickly—especially ammonium bicarbonate, which is highly volatile. The ammonia released from this breakdown not only reduces the effectiveness of the fertilizer but can also lead to ammonia toxicity in eggplants. To avoid this, it's recommended to use the deep trenching method. The trenches should be 5–8 cm deep, and after applying the fertilizer, the soil should be covered immediately and watered thoroughly to ensure full dissolution.
Second, proper timing and frequency are key when using nitrogen fertilizers. Eggplants require a large amount of nitrogen during the fruiting stage, but during high-temperature periods, it's better to apply smaller amounts more frequently. This "eat less but eat more often" approach helps prevent nutrient loss. Urea, for example, breaks down quickly in the soil, and if applied in large quantities at once, much of it may be lost before the plants can absorb it. In sandy soils, this loss is even more significant. It's best to apply no more than 20 kg of ammonium bicarbonate per acre, and to do so every 4–6 days with irrigation.
Third, a balanced fertilization strategy is essential. While eggplants need nitrogen, they also require adequate phosphorus and potassium. Many farmers only focus on nitrogen when top-dressing, but this can lead to an unbalanced nutrient supply. During the fruiting period, it's beneficial to apply phosphorus and potassium fertilizers 2–3 times. This not only boosts yield but also improves fruit quality and extends the harvesting period. A typical recommendation is to add 20 kg of phosphate fertilizer and 10 kg of potash fertilizer (such as potassium sulfate) each time.
By following these three practices—deep trenching, frequent small applications, and balanced fertilization—you can optimize nutrient uptake, reduce waste, and ultimately achieve healthier, more productive eggplant crops. These methods are especially important in hot weather, where traditional fertilization techniques may fall short. Always consider soil type, plant needs, and environmental conditions when planning your fertilization schedule.
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