What are the correct methods for fertilizing eggplants?
Seedling-stage fertilization: To grow seedlings with thick stems, short internodes and well-developed roots, the seedbed soil must be fertile. On 11.3 sq m of seedbed soil, apply 200 kg of decomposed organic fertilizer and 0.5 kg each of superphosphate and potassium sulfate, and mix the seedbed soil and fertilizers evenly. You can also apply 100-150 kg of mixed human manure and 1 kg of NPK compound fertilizer.
Seedling-stage fertilization: To grow seedlings with thick stems, short internodes and well-developed roots, the seedbed soil must be fertile. On 11.3 sq m of seedbed soil, apply 200 kg of decomposed organic fertilizer and 0.5 kg each of superphosphate and potassium sulfate, and mix the seedbed soil and fertilizers evenly. You can also apply 100-150 kg of mixed human manure and 1 kg of NPK compound fertilizer.
Base fertilizer: Eggplants like fertilizer and tolerate it well, so a heavy base fertilizer application is necessary. Before plowing, broadcast 5000-7000 kg of organic fertilizer per mu, together with 15 kg of superphosphate and 10 kg of potassium sulfate, then plow and prepare the land into beds; alternatively, before plowing, broadcast 3000-5000 kg of organic fertilizer per mu, then make ridges or beds, and at transplanting apply 1500 kg of organic fertilizer and 25-50 kg of nitrogen, phosphorus and potassium compound fertilizer in holes or furrows. You can also apply the trace elements zinc sulfate 1 kg and manganese sulfate 2 kg.
Topdressing: Eggplants have a long fruiting period and need repeated topdressing throughout their life. Nutrient uptake by eggplants increases rapidly after the full-bloom stage, so the key topdressing period is from when the first eggplant "opens its eyes" to the harvest of the four-door fruit. During this period, topdress once every 10-plus days, applying 15-20 kg of ammonium sulfate or 7.5-10 kg of urea, or 10-15 kg of ammonium nitrate per mu each time; of course, topdressing with 500-600 kg of decomposed human manure is best. The fertilizer can be applied in furrows, in holes, or washed in with irrigation water.
Note that in the late growth stage of eggplants it is best not to apply phosphorus fertilizer, so as to avoid promoting seed development in the fruit and hardening the seed coat, which lowers the commercial value of the eggplant fruit. During fertilization, be sure to follow the principle of organic fertilizer as the main input and chemical fertilizer as a supplement; the amount of chemical fertilizer must not be too large, especially nitrogen fertilizer, to avoid nutrients accumulating heavily at the flower buds, causing deformed fruit with malformed carpels during cell division, and even leading to the accumulation of nitrate in eggplant tissues.