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Modern way of farming fish and vegetables
Charles Mulamata (right) and wife have been engaged in aquaponics farming for 10 years. They rear fish and grow vegetables. PHOTO/FILE
What you need to know:
- The fish waste provides organic food for the plants, and the plants naturally filter the water for the fish.
Backyard farming in urban areas involving vegetable growing and rearing fish provides different opportunities for both commercial and home use.
It is possible to combine different farming methods in a simple and interesting way to the benefit of each produce.
Background
Aquaponics gardening can be used to grow vegetables and fish at the same time because the system maximises the potential of both plants and aquatic life. Farmers can combine aquaculture and hydroponic system which refers to growing plant and vegetable without the aid of soil. The system works because the fish provides the waste for the plants while the plants act as filters keeping the water clean for the fish to grow.
However most farmers engaged in aquaculture farming in the country mainly apply the technology of rearing various fish species in fish ponds and cage fish farming in the water bodies.
But a few are moving into adopting mixed aquaponics vegetable and fish farming as an income earning initiative.
One such a farmer who has adopted the technology is Charles Mulamata’s family that is engaged in fish breeding using aquaponics technology not necessarily for consumption but as a business initiative.
Seeds of Gold has gone ahead to research information about this technology and below are the details.
What location to consider
According to experts aquaponics systems come in various sizes and designs for a mini farm or commercial venture.
Farmers can locate an aquaponics system either outside or indoors. Outdoor locations can be a garden, balcony, backyard or open field. Other outdoor locations include the doorway, veranda and side or in front of house. Indoor locations are the garage, kitchen, basement, spare room and store. The only rule to indoor aquaponic is that it should have a minimum of seven hours of sunlight daily. The use of hydroponic grow light is an alternative to sunlight.
Symbiotic relationship
The fish and garden plants farmers selected should have similar water temperature requirements and PH levels. Vegetables thrive in aquaponic systems if paired with fresh water fish.
Various farmers may opt for various technology use which includes setting up their farm on rooftops, in an open compound, on their home verandas among others depending on suitability.
“Water that has fish feed waste is pumped from the tank into the bucket. The unclean water has mineral content that includes ammonium and nitrates that are absorbed through filtration by the plant roots to make it clean. Then the water flows through pipes by gravity, back into the tank and is re-circulated. There is (a) symbiotic relationship between the fish in the tank and the plants in the bucket,” says Mulamata.
Advantages
With this system, plants help purify water for fish to grow well, and fish provide valuable nutrients for plants from their own organic waste.
This model helps the farmer to grow vegetables, raise fish clean without soil or need to apply any chemical fertilisers. The closed cyclic development helps organisms grow in a completely natural way because the farmer simply needs to plant the seeds and wait for the harvest day.
Medium to use
What is required of the farmer is to ensure there is a large tank for raising fish and growing vegetables, depending on the size of the system. The tank can be about 300-1000ml wide, the vegetable tray from 50-100ml is reasonably arranged above the fish tank and fixed with an iron frame.
An automatic pump system, possibly with a timer placed in the aquarium, is responsible for sucking fish waste from the tank onto the vegetable tray, directly nurturing the growing vegetables.
Other requirements include water filters, sensors, timers, oxygen bubbles among others depending on the preferences of each farmer. The type of fish chosen for farming in this model is usually freshwater fish such as Nile perch, Tilapia, Lung fish, among others.
After a week of raising fish, they will begin to get used to the water environment. Farmers in the developed world who do not have time to feed the fish usually buy ready to use fish feeding equipment outside, depending on the design or size. These devices can feed fish automatically in about 2-3 weeks.
Farmers must ensure not to let the water to dry or get dirty because it will affect the growth of the fish.
In the first three months because the fish is still small, it is recommended to only sow vegetables that are easy to grow such as spinach, broccoli, cucumber, onions, and chili peppers.
After three months, the system begins to stabilise and the larger fish could grow with vegetables such as: amaranth, spinach, watermelon and squash.
Breeding
Mulamata keeps his fingerlings for 18 days after hatchery before selling them.
This is sold out to other farmers breeding fingerlings for nursery breeders. Each tiny fish fingerling is sold at Shs120. The farmer will breed this fingerling for a period of 30 days weighing 10 grammes ready to sell to nursery II breeders at Shs350.
The nursery breeder farmer will purchase this fingerling weighing 10 grammes and breed it for 30 days which he or she sells at Shs650 each.
The nursery II farmers sell this fingerlings to farmers who specialise in breeding fish ready for consumption in the open market.
It will take such a farmer between four and five months to breed the fish fingerlings.
The normal procedure of breeding fish in water ponds or fish cages takes about 10 months but with aquaponics, the period is shortened.
For plants, Mulamata says there is no need for weeding and the growth of the plants is significantly fast compared to the traditional way of cultivating crops. “The system has high initial costs but is self-benefiting since the waste from fish is the fertiliser for the plants,” says Mulamata.
Aquaponics
Aquaponics refers to the combination of aquaculture (fish farming) and hydroponics (crop farming) using mineral nutrient solutions, without soil). Nutrient-rich water resulting from raising fish provides a source of natural fertiliser for the growing plants which in turn helps to purify the water that the fish live in.
