Aquaponics system facilitates simultaneous nurturing of plants and fish by re-circulating water as well as the nutrients that are produced in the system for the growth of the plants as well as the species that are included in the system. This new method for simultaneous management of farm and fish pond is gaining momentum the world over since it provides a sustainable as well as cost-effective solution for farming and growing fish simultaneously.
Various types of warm-water and cold-water fish species can be raised using this method. The fish species that are widely cultivated using this method include perch, Arctic char, trout, bass, cod and tilapia.
Among all the fish species tilapia is the most suited for cultivation in aquaponics systems since the tilapia fish can withstand various fluctuations in the aquatic conditions such as temperature, oxygen content, dissolved substances and pH. Since tilapia fish has good demand in the market, cultivation of this variety is highly profitable also.
Cultivation of various plants is the other purpose of aquaponics system. Leafy greens and various herbs are cultivated in this system. However, it depends on the density of the fish tank and the nutrients that are present in the fish waste. The plants that are grown in the system absorb the nutrients that are present in the fish waste and the type of nutrients in the fish waste depends on the type of fish species that grow in the tank.
The water from the fish tank is drained out and filtered and used for irrigation of the plant. Since the fish waste is a rich source of nitrogenous fertilizer it is ideal for raising the leafy plants. The plants such as lettuce, spinach, watercress, basil and chives grow very well in aquaponics systems since the nutritional needs of these plants and herbs are very low.
Fruit-yielding plants like tomato and cucumber also can be cultivated in aquaponics systems. However, since the nutritional requirements of these plants are higher, the system must be sufficiently stocked as well as provided. Cucumbers and tomatoes grow healthy and give good yield in aquaponics system, provided the plants are fed with sufficient quantity of nutrition.
Filling the pots with compost is the most effective method to provide all the nutrients that are required by the plants. Root crops such as carrot and potato can give the yield only if they are grown in soil. Hence the aquaponics method of cultivation is not suitable to them.
Monitoring the water quality
The success of an aquaponics system also depends on the condition of the water that is used in the system. Fish, plants and water are the vital components of this system. In order to ensure safe as well as healthy environment for the fish that is grown in the system, the pH of the water that is stored in the system is to be carefully monitored. Since the fish as well as the plants in the systems are to be kept healthy and growing, periodic checking of the quality of the water using the right equipments is all the more important.
The farmer should also monitor the levels of dissolved oxygen, ammonia, carbon dioxide, chlorine, nitrates and nitrites in the water. The quality of water undergoes rapid change with changes in the density of fish in the tank, growth rate of the fish and the amount of feed they are provided. The fish species, fish density, plant species and other aspects determine the ratio of water in the fish tank to the hydroponic products. However as a general rule, the ratio of tank content to bed content will be 1:4.
Conversion of ammonia
Aquaponics system can be provided with biofilters that facilitate natural filtering out of the harmful substances from the water. When the pollutants are filtered out completely, the process of conversion of ammonia into nitrite and then to nitrate is made hassle-free.
In some of the systems, the fish waste is directly added into the system. The chemical process of conversion of toxic ammonia into nitrites and then to nitrate is facilitated by the gravel bed of the system. The gravel bed functions as a bioreactor and removes the dissolved solids from the water thereby providing the space for the nitrifying bacteria to get converted into nitrogenous fertilizer that provides the nutrients to the growing plants in the system.
Aquaponics system consumes only 10% of water required for regular farming. It provides an ideal method for food production in the backyards of houses.