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Type: Fern
Family: Salviniaceae
Native Range: Argentina, Brazil, Uruguay, Peru
Zone: 7 to 10
Height: 0.25 to 0.25 feet
Spread: 1.00 to 3.00 feet
Bloom Time: Non-flowering
Bloom Description: Non-flowering
Sun: Full sun to part shade
Water: Wet
Maintenance: High
Suggested Use: Annual, Water Plant, Naturalize, Rain Garden
Leaf: Colorful
Tolerate: Rabbit
Culture
Grow on still water in full sun to part shade. Scatter small bunches of plants on the water surface after last frost date. Spreads quickly in optimum conditions. Net out excess plants as needed. Can spread rapidly in frost-free climates. In the wild, it survives winter in cold weather climates by way of overwintering bodies that sink to the bottom in fall and rise to the surface in spring only after temperatures have warmed up. This phenomenon is usually not seen in home water gardens in the St. Louis area where it is recommended that some plants be lifted each year in fall before first frost and overwintered in a saucer of moist soil in a bright frost-free area or in an aquarium.
Noteworthy Characteristics
Azolla filiculoides, commonly called mosquito fern, is a deciduous, free-floating, aquatic perennial fern that forms rapidly expanding, moss-like mats of foliage (to 1/2” tall) on still water surfaces. In optimum conditions, the foliage becomes so dense as to reportedly prevent mosquito larva from developing and hatching, hence the common name. It is a popular addition to water gardens and ponds, where it not only provides attractive foliage cover but also discourages algae growth and helps keep waters clear. Foliage is bright green in shade, but develops attractive purplish-rose tints in full sun. All plants turn reddish-purple in fall as temperatures cool. Pinnately branched stems are densely clad with minute, often overlapped, two-lobed leaves (1/4” long) in two rows. Tiny roots trail downward from the lower surfaces of the stem forks. This fern is native to lakes, ponds, streams and rivers in both North and South America.
Genus name comes from the Greek words azomeaning to dry and olluo meaning to kill. The plants will easily die when they become too dry.
Specific epithet means resembling fern.
Problems
No serious insect or disease problems.
Uses
Free floating aquatic perennial for water gardens”
OK now the cool part https://www.milkwood.net/2012/08/06/azolla-water-fern-as-protein-rich-animal-feed/
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(A note that the above clip is in the garden at Quoll Hollow, where we live now on melukerdee country, and the references to Milkwood Farm below are from our years up north on Wiradjuri country)
Azolla is a native water plant with some seriously exciting attributes for anyone looking to develop closed-loop cycles for organic animal feed. It’s high in protein and minerals, fixes nitrogen, is palatable to chickens, pigs, goats, ducks and cows, and can be grown on any closed body of fresh water.
At Milkwood Farm we have many emerging animal production systems, and we’re looking for cost and energy effective ways to produce organic feed for them, using passive and regenerative techniques. Azolla looks like a great tool for us.
Pastured pullets getting into Azolla for breakfast – photo via solraya.blogspot.com
Azolla growing on the pond at Milkwood, ignored until now but quite happy regardless
Azolla in mid-winter at Milkwood Farm. We get hard frosts, which causes the Azolla to die back and retreat to the edges, but doesn’t seem to kill it altogether, which is great.
Azolla is an excellent aquatic green manure plant, and was until recently used extensively in Vietnam, China and other parts of Asia in rice paddies, where it would cover the surface of the water in the paddy and out-compete weeds while the rice grew, fixing nitrogen and contributing fertility as it went.
Being placed as we are in terms of climate and rainfall, we’ve no plans to do rice paddies in the near future. What we do have however is a desire to develop high-protein sources of food for chickens and pigs and hopefully some ducks and milking cows sometime soon.
Down in the valley below us is prime lucerne-growing country – Mudgee is a very good place to buy cheap lucerne hay, and we periodically get in truckloads of mulch-quality lucerne which is a bit mouldy, but fabulous for mulching plantings, vegetable beds, adding to compost piles and generally establishing fertility.
However we’re not close enough to the valley country to fetch large quantities from down the road without incurring steep cartage costs, and we’ve not got good enough soil on Milkwood Farm to grow it ourselves in quantity. So we’ve been looking for other high protein and nitrogen sources that are multipurpose, and that can conceivably be grown successfully on-site.
The great thing about Azolla is that not only is it a high value feed for animals and a great option for adding to compost and to the market garden plantings, but that it grows itself without taking too much fertility from the system.
It’s a little bit like free energy, and highly regenerative as a system component.
The growing of Azolla is very easy: put some in a dam or pond, and watch it grow. It fixes nitrogen from the air and minerals from the water. It does deplete the nutrient content of the dam, so if you were trying to grow other things in the dam that you wanted to flourish (lotus, water chestnuts etc) I’m assuming you’d want them somewhere else, unless that dam has a seriously high nutrient load.
Within a permaculture system, if you have a series of dams and swales you would probably want to grow Azolla in the lower parts of that system, to make the most of nutrient concentration that is going to be greater at the bottom of such a system.
We’re trying Azolla out in the small pond beneath the house dam, which it happily colonized entirely over a couple of months, until the hard frosts of winter arrived, at which point it died off and shrank back to the sides. This was actually before we realized how awesome Azolla was, otherwise we’d have harvested it before the cold snap.
In Spring we’ll add Azolla to the bottom dam and see how it goes in our climate, but we’re hopeful it will do well and that we can start harvesting regularly to start supplementing feed aroudn the farm,a nd hopefully adding some of it to ongoing compost production as well
Azolla benefits:
– Hosts a symbiotic blue green algae Anabaena azolle, which is responsible for the fixation and assimilation of atmospheric nitrogen.
– Can double in size every several days under optimal nutrient and water temperate conditions
– Green manure plant for paddy agriculture for weed supression and fertility (used extensively in organic duck and rice systems)
– Nitrogen and mineral source for compost making
– 25-30% Protein, and low in lignin with makes it digestible to many animals, as well as nutritious
– Rich in essential amino acids, vitamins (vitamin A, vitamin B12 and Beta- Carotene), growth promoter intermediaries and minerals like calcium, phosphorous, potassium, ferrous, copper, magnesium etc.
– On a dry weight basis, it contains 25 – 35 percent protein, 10 – 15 percent minerals and 7 – 10 percent of amino acids, bio-active substances and bio-polymers.
– Palatable to: ducks, chickens, pigs, cows, goats, sheep and rabbits (and probably lots of others too)
– Can increase milk production in cows by 15-20%
– Azolla is a nutrient feeder and prevents Algal blooms in farm dams as a result, keeping water more usable for stock
– Can be easily harvested with a scoop net, or grown in enclosed, floating rings which can be pulled to the edge for easy harvest
– After initial collection/purchase, you get a lifetime supply!
Downsides of Azolla:
– Being as it is a water plant, Azolla can clog up water lines and pumps coming from farm dams if that dam is fully colonized with Azolla.
– Dead Azolla in a body of water can reduce the waters’ oxygen content for a time
– Given its growth rate, do check if Azolla is considered invasive where you are (like in parts of NSW). If so, don’t encourage it, sieve out what’s there and feed your animals on that (or compost it), and then find anpother way to enhance your chickens diet – sprouted feedstock grain? Works great!
As you might guess from this glowing report card, there are much interest and active development in Azolla as a low-cost, organic and nutrient rich animal feed around the globe from various institutions, in addition to the cultures that have been using it for centuries.
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Azolla nutritional values
The following nutritional values for fresh and dry azolla as a livestock feed are from Feedipedia: ‘an on-line encyclopedia of animal feeds’.
Feedipedia is an open access information system on animal feed resources that provides information on nature, occurrence, chemical composition, nutritional value and safe use of nearly 1400 worldwide livestock feeds.
Feedipedia is a joint project of INRA (Institut National de la Recherche Agronomique, French National Institute for Agricultural Research), CIRAD (Centre de Coopération Internationale en Recherche Agronomique pour le Développement, French Agricultural Research Center for International Development, AFZ (Association Française de Zootechnie, French Association for Animal Production) and FAO (Food and Agriculture Organization of the United Nations).
The main objective of Feedipedia is to provide extension and development workers, planners, project formulators, livestock farmers, science managers, policy makers, students and researchers with the latest scientific information to help them identify, characterize and properly use feed resources to sustainably develop the livestock sector. This is particularly important in emerging and developing countries where feed resources available locally are often under-utilized due to lack of information. Providing global knowledge on feed resources, including unconventional and lesser known ones, contributes to the development and use of innovative and appropriate feeding options and strategies.
Feedipedia’s datasheets contain the following information:
-
Feed names, including vernacular and scientific names
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Description of the plants or plant parts/products used as feed
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Feeding recommendations for the main livestock species: cattle, sheep, goats, camels, poultry, pigs, rabbits, horses, fish and crustaceans
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Tables of composition and nutritive value
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Illustrations, including photos and processing charts
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Distribution and basic agronomic information
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Forage management
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Processes for improving nutritional value
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Potential constraints such as presence of anti-nutritional and toxic factors
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Environmental impact of the production and use of feeds
Feedipedia can be contacted here.
The values below from Feedipedia are for fresh azolla:
| Main analysis | Unit | Avg | SD | Min | Max | Nb | |
|---|---|---|---|---|---|---|---|
| Dry matter | % as fed | 6.7 | 1.3 | 5.1 | 8.7 | 8 | |
| Crude protein | % DM | 20.6 | 3.5 | 13.9 | 28.1 | 15 | |
| Crude fibre | % DM | 15 | 3.5 | 11.3 | 22.8 | 9 | |
| NDF * | % DM | 43.8 | 5.9 | 35.4 | 52.3 | 6 | |
| ADF ** | % DM | 31.8 | 6.4 | 24 | 38.9 | 5 | |
| Lignin | % DM | 11.4 | 1.7 | 9.3 | 13.5 | 5 | |
| Ether extract | % DM | 3.8 | 1.3 | 1.9 | 5.1 | 9 | |
| Ash | % DM | 15.9 | 3.5 | 9.8 | 21.6 | 12 | |
| Starch (polarimetry) | % DM | 4.1 | 2.7 | 5.5 | 2 | ||
| Gross energy | MJ/kg DM | 17 | * | ||||
| Minerals | Unit | Avg | SD | Min | Max | Nb | |
| Calcium | g/kg DM | 11 | 4.1 | 5.8 | 17 | 8 | |
| Phosphorus | g/kg DM | 6.1 | 5.5 | 0.3 | 15.5 | 11 | |
| Potassium | g/kg DM | 17.4 | 3.7 | 10.9 | 22.5 | 7 | |
| Sodium | g/kg DM | 9 | 4.3 | 2.8 | 12.5 | 4 | |
| Magnesium | g/kg DM | 5 | 0.8 | 3.9 | 6.1 | 5 | |
| Manganese | mg/kg DM | 762 | 438 | 208 | 1429 | 5 | |
| Zinc | mg/kg DM | 38 | 28 | 11 | 77 | 5 | |
| Copper | mg/kg DM | 16 | 7 | 10 | 28 | 5 | |
| Iron | mg/kg DM | 3900 | 3794 | 711 | 8200 | 5 | |
| Amino acids | Unit | Avg | SD | Min | Max | Nb | |
| Alanine | % protein | 6.4 | 1 | 5.3 | 7.4 | 3 | |
| Arginine | % protein | 5.9 | 0.7 | 5.1 | 6.6 | 3 | |
| Aspartic acid | % protein | 9.3 | 1 | 8.2 | 10.3 | 3 | |
| Cystine | % protein | 1.6 | 0.8 | 0.7 | 2.3 | 3 | |
| Glutamic acid | % protein | 12.6 | 1 | 11.6 | 13.5 | 3 | |
| Glycine | % protein | 5.6 | 1.1 | 4.5 | 6.6 | 3 | |
| Histidine | % protein | 2.1 | 0.4 | 1.6 | 2.4 | 3 | |
| Isoleucine | % protein | 4.5 | 0.8 | 3.7 | 5.4 | 3 | |
| Leucine | % protein | 8.4 | 1.2 | 7 | 9.2 | 3 | |
| Lysine | % protein | 4.7 | 1.1 | 3.5 | 6.5 | 5 | |
| Methionine | % protein | 1.4 | 0.3 | 1.2 | 1.9 | 5 | |
| Phenylalanine | % protein | 5.4 | 0.2 | 5.2 | 5.6 | 3 | |
| Proline | % protein | 4.9 | 1.7 | 3.5 | 6.8 | 3 | |
| Serine | % protein | 4.5 | 0.9 | 3.9 | 5.6 | 3 | |
| Threonine | % protein | 4.7 | 0.7 | 4 | 5.3 | 3 | |
| Tryptophan | % protein | 1.8 | 1.5 | 2 | 2 | ||
| Tyrosine | % protein | 3.6 | 0.5 | 3.2 | 4.1 | 3 | |
| Valine | % protein | 5.5 | 1.5 | 3.8 | 6.8 | 3 | |
| Ruminant nutritive values | Unit | Avg | SD | Min | Max | Nb | |
| OM digestibility, ruminants (gas production) | % | 64 | 1 | ||||
| ME ruminants (gas production) | MJ/kg DM | 7.4 | 1 | ||||
| Pig nutritive values | Unit | Avg | SD | Min | Max | Nb | |
| Energy digestibility, growing pig | % | 63.4 | 1 | ||||
| DE growing pig | MJ/kg DM | 10.4 | 1 |
KEY: Avg: average or predicted value; SD: standard deviation; Min: minimum value; Max: maximum value; Nb: number of values (samples) used.
* NDF: fraction of the cell walls considered to be roughly equivalent to hemicellulose, true cellulose and lignin.
** ADF: Acid Detergent Fiber, fraction of the cell walls according to Van Soest, considered to be roughly equivalent to true cellulose and lignin.
References
CIRAD, 1991. Laboratory data 1963-1991. CIRAD
The values below are for dried Azolla:
| Main analysis | Unit | Avg | SD | Min | Max | Nb | |
|---|---|---|---|---|---|---|---|
| Dry matter | % as fed | 91.9 | 1.9 | 88.6 | 94.9 | 8 | |
| Crude protein | % DM | 21.5 | 5.3 | 10.7 | 31.8 | 18 | |
| Crude fibre | % DM | 16.1 | 4.3 | 7.3 | 24.3 | 17 | |
| NDF * | % DM | 49.5 | 8.3 | 36.9 | 62.1 | 9 | |
| ADF ** | % DM | 40.4 | 10.8 | 24.5 | 56.8 | 9 | |
| Lignin | % DM | 8.9 | 4.5 | 13.2 | 2 | ||
| Ether extract | % DM | 3.3 | 0.9 | 1.6 | 5.2 | 16 | |
| Ash | % DM | 19.2 | 5.8 | 11 | 36.1 | 18 | |
| Gross energy | MJ/kg DM | 16.4 | |||||
| Minerals | Unit | Avg | SD | Min | Max | Nb | |
| Calcium | g/kg DM | 12.5 | 1.6 | 10.8 | 14.3 | 4 | |
| Phosphorus | g/kg DM | 6.7 | 5 | 2.1 | 12.9 | 4 | |
| Potassium | g/kg DM | 12.5 | 1 | ||||
| Sodium | g/kg DM | 0 | 1 | ||||
| Magnesium | g/kg DM | 3.5 | 1 | ||||
| Manganese | mg/kg DM | 174 | 1 | ||||
| Zinc | mg/kg DM | 88 | 1 | ||||
| Copper | mg/kg DM | 17 | 1 | ||||
| Iron | mg/kg DM | 756 | 1 | ||||
| Amino acids | Unit | Avg | SD | Min | Max | Nb | |
| Alanine | % protein | 5.8 | 1 | ||||
| Arginine | % protein | 6.4 | 1.5 | 5 | 8.9 | 8 | |
| Aspartic acid | % protein | 8.3 | 1 | ||||
| Cystine | % protein | 0.9 | 0.8 | 0.9 | 2 | ||
| Glutamic acid | % protein | 9.6 | 1 | ||||
| Glycine | % protein | 4.9 | 4.6 | 5.2 | 2 | ||
| Histidine | % protein | 1.6 | 0.4 | 1.2 | 2.2 | 7 | |
| Isoleucine | % protein | 3.9 | 0.8 | 2.8 | 5.2 | 8 | |
| Leucine | % protein | 8.7 | 1.4 | 7.4 | 11.4 | 8 | |
| Lysine | % protein | 5.6 | 1.3 | 3.8 | 7.9 | 8 | |
| Methionine | % protein | 1.5 | 1.5 | 1.6 | 2 | ||
| Phenylalanine | % protein | 4.7 | 4.6 | 4.7 | 2 | ||
| Proline | % protein | 4 | 1 | ||||
| Serine | % protein | 4.1 | 4 | 4.2 | 2 | ||
| Threonine | % protein | 4.3 | 0.8 | 3.4 | 5.6 | 8 | |
| Tryptophan | % protein | 1.2 | 0.5 | 1.8 | 2 | ||
| Tyrosine | % protein | 3.1 | 3 | 3.2 | 2 | ||
| Valine | % protein | 4.5 | 0.9 | 3.2 | 5.5 | 8 | |
| Poultry nutritive values | Unit | Avg | SD | Min | Max | Nb | |
| AMEn broiler | MJ/kg DM | 4.4 | 1 |
KEY: Avg: average or predicted value; SD: standard deviation; Min: minimum value; Max: maximum value; Nb: number of values (samples) used.
* NDF: fraction of the cell walls considered to be roughly equivalent to hemicellulose, true cellulose and lignin.
** ADF: Acid Detergent Fiber, fraction of the cell walls according to Van Soest, considered to be roughly equivalent to true cellulose and lignin.
References
Basak et al., 2002; Datta et al., 2011; Domínguez et al., 1996; Gavina, 1994; Khatun et al., 1999; Kumar et al., 2012; Leterme et al., 2010; Naegel, 1997; Namra et al., 2010.
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