Natural fertilizer such as cow/chicken manure, green manure and compost and chemical fertilizer can be used to be abundant of natural food and to reduce the supplementary feed.
Fertilizers promote the growth of phytoplankton and production of natural food.
15-20 kg of urea and 7.5-10 kg of TSP per ac can be used for normal primary production.
TSP must be soaked overnight and at the next morning, 10-11 am, mix urea, water and soaked TSP, and then broadcast them evenly to grow plankton on the surface.
Since fertilizers, especially TSP, take time to dissolve into water, should avoid direct application without soaking in water.
Fertilization should be used weekly or biweekly throughout the cultural period so that natural food can be maintained.
