Chinyere Anyanwu, [email protected]
Investors in livestock farming in the country are of a general consensus that the cost of feed alone accounts for over 65 per cent of production cost and therefore a major concern. To reduce the cost of production, therefore, an alternative, nutritious and tasty livestock feed has come to the rescue of the farmers to augment traditional feeds.
The feed being referred to is azolla, a freshwater, free-floating fern with the reputation of being one of the fastest growing plants in the world. It is the most promising aquatic plant for livestock feed due to its ease of cultivation, productivity and nutritive value. One hectare of azolla can produce 500-700kg of protein per month. Its composition and rapid growth potential, therefore, makes it one of the most economic and efficient feed substitutes for livestock.
Azolla is very rich in proteins, essential amino acids, vitamins (vitamin A, vitamin B12 and beta-carotene), growth promoter intermediaries and minerals like calcium, phosphorous, potassium, ferrous, copper and magnesium, among others. It is able to proliferate without inorganic nitrogen fertilisation. Its high rate of growth in water is amazing without the need to displace existing crops or natural ecological systems.
Azolla can be used as an ideal feed for cattle, fish, pigs and poultry, and is also of value as a bio-fertiliser for rice paddies. It is popular and cultivated widely in countries like China, Vietnam, and the Philippines and is gaining popularity in Nigeria.
Its cultivation requires minimal amount of investment, hence it is a low-cost alternative for good feed and good biofertiliser.
Benefits of azolla
Livestock feed: Azolla contains very high proteins, amino acids, vitamins (vitamin A, vitamin B12, beta-carotene) and minerals, so it is the excellent nutrient feed for livestock. Also, azolla has low lignin content, which makes it easy for animals to digest.
It has been observed that feeding azolla to poultry birds improves the weight of broiler chicken and increases the egg production of layer birds.
In cattle, it can increase overall milk yield by 15-20 per cent when 1.5-2kg of azolla is combined with regular feed.
Azolla is a nutrient feeder and prevents algal blooms in farm dams thereby keeping water more usable for stock.
It can be easily harvested with a scoop net or grown in enclosed, floating rings which can be pulled to the edge for easy harvest.
Biofertiliser: Azolla fixes atmospheric nitrogen and is, therefore, used as green manure.
It has been known to be of immense benefit to rice farmers. When cultivated in paddy farm, there is increase in rice production by 20 per cent.
Weed control: Azolla plant can form a thick layer on water surfaces, so it is used for weed control in paddy farms. It forms a thick layer and covers all farm area and works as organic mulching, which doesn’t allow weeds to grow. Also, it slows water evaporation rate and maintains soil moisture for a long time.
Mosquito control: Azolla is also called “mosquito fern” due to its ability to restrict mosquito breeding process.
Cultivation process: Azolla can be grown abundantly in lakes, rice fields with irrigation, concrete tanks, or any dug-out pond that can hold water. To make azolla cultivation pond, select partially shaded area because azolla needs only 30 per cent sunlight; too much sunlight will destroy the plant. Any area under a tree is preferable.
Create the pond with the help of a silpauline sheet. Silpauline is a polythene tarpaulin, which is resistant to the ultra violet radiation in sunlight. A pit of 2 x 2 x 0.2m is dug as a first step. All corners of the pit should be at the same level so that a uniform water level can be maintained. The pit is covered with plastic gunnies (coarse sacks made of jute fibre) to prevent the roots of nearby trees piercing the silpauline sheet, which is spread over the plastic gunnies. About 10-15kg of sieved fertile soil is uniformly spread over the silpauline sheet.
Slurry made of 2kg cow dung and 30g of super phosphate mixed in 10 litres of water, is poured onto the sheet. One of its attractions is that the dung produced by livestock is used to help fertilise the azolla plants which, in turn, provide nutrition for the livestock. More water is poured on to raise the water level to about 10cm. About 0.5-1kg of fresh and pure culture of azolla is placed in the water. This will grow rapidly and fill the pit within 10-15 days. From then on, 500-600g of azolla can be harvested daily. Because azolla grows rapidly, there is need to harvest daily to avoid overcrowding.
A mixture of 20g of super phosphate and about 1kg of cow dung should be added once every five days to maintain rapid multiplication of the azolla and to maintain the daily yield of 500g. A micronutrient mix containing magnesium, iron, copper, sulphur, etc., can also be added at weekly intervals to enhance the mineral content of azolla.
Where to buy azolla plant: Azolla plant/seeds can be bought from fellow farmers, local agriculture officers or some agricultural research organisations as well as from online agriculture websites.
If the azolla pond is taken good care of, good quality feed can be harvested everyday, which will reduce cost of feed and fertiliser. Azolla is a protein-rich, alternative sustainable animal feed fresh from the farm.
Harvesting azolla: Harvest the floating azolla plants using a plastic tray having holes of 1-2cm mesh size to drain the water.
Wash it to get rid of the cow dung smell. Washing also helps in separating the small plants which drain out of the tray. The plants, along with water in the bucket, can be poured back into the original bed.
For use as a livestock feed, the fresh azolla should be mixed with commercial feed in 1:1 ratio to feed livestock. After a fortnight of feeding on azolla mixed with concentrate, livestock may be fed with azolla without added concentrate.