How to Cultivate Spirulina? Detailed Explanation of Methods and Technical Key Points
How to cultivate spirulina?
There are about 30 species of spirulina. It is a relatively large species, and under artificial cultivation conditions, each 667 sq m of water surface can produce an annual yield of more than 1,500 kg. Spirulina is high in protein, fat and vitamins, and contains amino acids essential to fish. Adding its dry powder to artificial compound feed for fish can accelerate growth rate, improve reproductive capacity and make fish coloration more vivid.
(1) Indoor cultivation Prepare the culture solution in the ratio of phosphate fertilizer 0.1 : quicklime 0.1 : cow dung 1 : pond mud 100 : well water 1000, pour it into a round glass tank with an inner diameter of 30 cm and a depth of 20 cm, then place the tank inside a glass cabinet that allows natural light to enter. Two 40-watt fluorescent tubes are mounted above the tank, about 20 cm from the liquid surface. Wait until the temperature of the culture solution is close to the temperature of the algal seed solution before adding the algal seed. Add 40-50 ml of algal liquid containing 300,000-500,000 algal cells per ml to each tank, so that the concentration in the tank is preferably about 3 million algal cells per liter. The water temperature of the culture tank is 24°C-28°C, and generally after 5-7 days of cultivation it can be harvested. Harvest an amount of algal liquid equivalent to 1/3-2/3 (60-120 ml) of the surface water, then add water equal to the harvested amount. Generally, after 3-5 harvests per tank, the tank should be changed and a new culture solution prepared for renewed cultivation.
The pond mud used to prepare the culture solution is best black pond mud with a water content of 20%-40%. It is also required to select pond mud from ponds that have been thoroughly cleared and have a clean water source. At the same time, pay attention to avoiding contamination during collection, water filling, inoculation and harvesting, so as to prevent the introduction of organisms harmful to algal reproduction. Once discovered, they should be removed promptly.
(2) Outdoor cultivation When cultivating in ponds, first drain the pond water and use about 75 kg of quicklime per 667 sq m to clear the pond. Then evenly spread 750 kg of cow dung on the pond bottom, spread the pond mud evenly, and then fill with new water to a depth of about 0.5 m. Wait until the water temperature stabilizes above 20°C, then introduce the seed source. After 7-10 days, spirulina blooms appear. When they form in large quantities, the blooms appear as emerald-green floccules.
Analysis of the water quality of the algal culture pond shows: each liter of water contains 0.15 g of quicklime, 0.99 g of cow dung and 0.1 g of phosphate fertilizer, which is basically consistent with the preparation ratio of the indoor culture solution, and all are within the suitable range for spirulina.
When the culture pond first receives the seed source, the water level should be shallow to help raise the water temperature. Generally, 0.5 m deep is sufficient. After the blooms form, add water to deepen the water level. And supplement fertilizer according to the amount of water added. When applying base fertilizer, apply it in full at one time, and calculate the fertilizer amount based on a water depth of 0.5 m.
During the peak reproduction period of spirulina, it dies very quickly under strong sunlight. The oxygen consumption from decomposition of dead algal cells and their products affects water quality, and can also cause fish to gasp at the surface. At this time, old algal cells should be removed promptly and new water injected to remedy the situation. When large amounts of zooplankton or other algae grow, they should be removed promptly so as not to affect the growth of spirulina.
If, due to limited conditions, there is no certainty of success in cultivating in ponds, you can first cultivate in small water bodies in an outdoor shed covered with plastic film. This is because using a plastic shed to regulate water temperature is relatively easy to control.
(1) Indoor cultivation Prepare the culture solution in the ratio of phosphate fertilizer 0.1 : quicklime 0.1 : cow dung 1 : pond mud 100 : well water 1000, pour it into a round glass tank with an inner diameter of 30 cm and a depth of 20 cm, then place the tank inside a glass cabinet that allows natural light to enter. Two 40-watt fluorescent tubes are mounted above the tank, about 20 cm from the liquid surface. Wait until the temperature of the culture solution is close to the temperature of the algal seed solution before adding the algal seed. Add 40-50 ml of algal liquid containing 300,000-500,000 algal cells per ml to each tank, so that the concentration in the tank is preferably about 3 million algal cells per liter. The water temperature of the culture tank is 24°C-28°C, and generally after 5-7 days of cultivation it can be harvested. Harvest an amount of algal liquid equivalent to 1/3-2/3 (60-120 ml) of the surface water, then add water equal to the harvested amount. Generally, after 3-5 harvests per tank, the tank should be changed and a new culture solution prepared for renewed cultivation.
The pond mud used to prepare the culture solution is best black pond mud with a water content of 20%-40%. It is also required to select pond mud from ponds that have been thoroughly cleared and have a clean water source. At the same time, pay attention to avoiding contamination during collection, water filling, inoculation and harvesting, so as to prevent the introduction of organisms harmful to algal reproduction. Once discovered, they should be removed promptly.
(2) Outdoor cultivation When cultivating in ponds, first drain the pond water and use about 75 kg of quicklime per 667 sq m to clear the pond. Then evenly spread 750 kg of cow dung on the pond bottom, spread the pond mud evenly, and then fill with new water to a depth of about 0.5 m. Wait until the water temperature stabilizes above 20°C, then introduce the seed source. After 7-10 days, spirulina blooms appear. When they form in large quantities, the blooms appear as emerald-green floccules.
Analysis of the water quality of the algal culture pond shows: each liter of water contains 0.15 g of quicklime, 0.99 g of cow dung and 0.1 g of phosphate fertilizer, which is basically consistent with the preparation ratio of the indoor culture solution, and all are within the suitable range for spirulina.
When the culture pond first receives the seed source, the water level should be shallow to help raise the water temperature. Generally, 0.5 m deep is sufficient. After the blooms form, add water to deepen the water level. And supplement fertilizer according to the amount of water added. When applying base fertilizer, apply it in full at one time, and calculate the fertilizer amount based on a water depth of 0.5 m.
During the peak reproduction period of spirulina, it dies very quickly under strong sunlight. The oxygen consumption from decomposition of dead algal cells and their products affects water quality, and can also cause fish to gasp at the surface. At this time, old algal cells should be removed promptly and new water injected to remedy the situation. When large amounts of zooplankton or other algae grow, they should be removed promptly so as not to affect the growth of spirulina.
If, due to limited conditions, there is no certainty of success in cultivating in ponds, you can first cultivate in small water bodies in an outdoor shed covered with plastic film. This is because using a plastic shed to regulate water temperature is relatively easy to control.