Calcium Potassium Nitrogen ratio Fundamental to Fish Pond Productivity ?
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Answer:
1. Fertilizers are natural or synthetic substances that are used in ponds to increase the production of the natural food organisms to be eaten by the fish. These organisms include phytoplankton*, zooplankton* and insects (see Chapter 10, ). They are all part of a complex food web* converging toward fish production. By increasing the availability of major nutrients, fertilizers promote the development of planktonic algae, which provide food for many fish. Fertilization also leads to the development of animals which feed on algae, including some fish such as the Chinese silver carp and the Nile tilapia.
Explanation:
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Explanation:
This factsheet by the Southern Regional Aquaculture Center (SRAC) gives information on fertilizing fish ponds.
Farmers know that proper fertilization can greatly increase crop yields. Similarly, pond fertilization can increase fish yields three to four times. Also fish will be in better condition, and the quality of catch by fishermen usually improves. Fertilizers used in ponds stimulate the growth of microscopic plants called algae or plankton. As primary elements of the food web, algae are eaten by microscopic animals called zooplankton and insects which serve as food for bream, which in turn are eaten by bass. Algae also make the water turn green, which helps to shade the pond bottom, preventing growth of troublesome rooted weeds and filamentous algae commonly called pond "moss or pond weeds."
Types and Grades of Fertilizer
There are many commonly used fertilizers produced for a variety of applications. Fertilizer manufacturers are required to list the grade on each fertilizer container by the percent of nitrogen (N), phosphorus (P) as phosphoric acid (P2O5) and potassium (K) as potassium monoxide (K2O). Therefore, a 20-20-5 grade fertilizer contains 20 percent nitrogen, 20 percent phosphorus as P2O5 and 5 percent potassium as K2O. "Complete" fertilizers contain N, P2O5, and K2O while "incomplete" fertilizers contain only one or two of these elements. Common incomplete fertilizer sources are normal superphosphate (0-20-0), triple superphosphate (0-46-0), diammonium phosphate (18-46-0) and liquid ammonium polyphosphate (10-34-0). Examples of common complete fertilizers are 13-13-13, 20-20-5, and 4-12-12.
Additions of phosphorus in ponds usually provide a much greater increase in fish production than from either nitrogen or potassium. However, nitrogen in combination with phosphorus is sometimes better than phosphorus added alone.
Liquid fertilizers are generally superior to the traditional granular form fertilizers in promoting rapid growth of plankton algae in farm ponds. This is because the nutrients are immediately in solution, making them more rapidly available to the algae. Also, smaller applications of liquid fertilizers (more as concentrates) can be used which may reduce the cost and labor of application but still improve the effectiveness of pond fertilization.
Common grades of liquid ammonium polyphosphate fertilizer are 10-34-0 and 11-37-0. Liquid ammonium orthophosphate, commonly sold as a 13-38-0 grade, can also be used. Nutrients are found in a ratio of about 1:3 in liquid fertilizers.
Any grade of liquid fertilizer can be used, as long as approximately 3 to 4 pounds of phosphorus as P2O5 are applied per application.
In recent years, fertilizer formulations which contain all three nutrients have become popular as a result of their effectiveness. In a dry, flour-like form, the 12- 48-8 formulation produces excellent phytoplankton blooms which vigorously stimulate bream and bass growth.
Standard Fertilization Schedule
The following standard fertilization schedule can be used with any of the fertilizers and rates recommended in the fertilization table.
Make the first application of fertilizer in late February or early March. (When water reaches 60 degrees) Follow with two additional applications at two-week intervals.
Make three more applications at three-week intervals.
Recommended Fertilization Rates for Different Fertilizers Used in Fish Ponds
