About Lesson
Fertilization level depends on secchi disk transparency value
|
Secchi disk transparency |
Management/Control |
|
< 25 cm |
No fertilization; observe fish for signs of dissolved oxygen depletion; increase water flow if necessary. |
|
25-40 cm |
No fertilization; regularly observe the fish behavior |
|
40-60 cm |
Routine fertilization necessary |
|
>60 cm |
Routine fertilization necessary; possible with an increase dose. |
Don’t fertilize the pond if:
- Exchange rate of water is excessive.
- Too much vegetation
- Too much aquatic vegetation
- Water is too muddy or dark-colored, and transparency is limited.
- Plankton turbidity is too high
Application of organic and inorganic fertilizers
a. Organic fertilizers:
- Heaping at a corner of the pond with a sunny exposure.
- Making Platforms about 30 cm under water
b. Inorganic fertilizers:
- Dissolved in water and spray all over the pond.
Fertilizer dose
- Nitrogen fertilizer ( Semi-intensive system): 0.2-0.4 g N/m2/day
- Phosphorous fertilizer: 0.1-0.2 g P/m2/day.
- Manure: 120-150 kg/ha/day.