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Should I add Azolla to my pond?

Posts: 93

posted 10 years ago

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This year we had very little rain leading into the summer and we lost a lot water in our irrigation pond to evaporation before we even started pumping up to the fields.
I am thinking about adding Azolla to my pond to combat this evaporation next year but I am a bit concerned that if I decide that this was a bad idea, I will never be able to remove it.
On my farm I have chickens, geese, turkeys, horses and cows so this could become a secondary stream of feed and it could also help combat that ugly algae that blooms all summer long and ruins my pretty view. From what I have read, a layer of azolla can conserve as much as 20% of the evaporative losses.
Sounds good so far but having never before seen a pond covered in azolla, I don't know if it looks terrible, or if the stuff stinks when there is a lot of it, or if it kills frog populations, etc.
If anybody has any experience with this stuff, I would sure like to hear about it.

https://en.wikipedia.org/wiki/Azolla

allen lumley

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Posts: 4154

Location: Northern New York Zone4-5 the OUTER 'RONDACs percip 36''

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posted 10 years ago

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Chad Duncan : Yes very interesting, I noticed that the article claims a self limiting condition at higher latitudes- what is your location how often and or for how
long is your pond frozen over !

I also note that this plant is a heavy metal collector, I am sure that there must be a way to Test for high Heavy Metal levels - perhaps 1st drying the plant, then
burning it to ash and then testing the ash-

I certainly would recommend a test like this unless one was very sure that both the local soils and water And the Upstream soils and waters were never exposed
to Mining Smelting, A blacksmiths operation or perhaps a leather tannery

I am posting a link to a Geoff Lawton Video where he discusses oxygenation of the pond and also creating floating Islands that work to reduce water evaporation
simply by its presence by shading and cooling the water !

http://www.geofflawton.com/fe/61799-permaculture-fishponds

Please follow-up with your decision on whether you use this water fern or not For the Good of the Crafts ! Big AL

Success has a Thousand Fathers , Failure is an Orphan

LOOK AT THE " SIMILAR THREADS " BELOW !

Alder Burns

pollinator

Posts: 1765

Location: southern Illinois, USA

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posted 10 years ago

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It sounds like a good idea to me. I've had it before, and like you, I had plenty of potential uses planned for it if it became abundant. I used to float a long piece of bamboo out there and use it as a boom to gather the stuff together and haul it out of the pond when it had completely covered the surface. I had fish in the pond and didn't want the shading of the azolla to shut down the plankton beneath, so my goal was to harvest it and prevent it from completely covering the surface. After several harvests, it began to turn purple, which my reading tells me is a phosphorus deficiency. So if you want a significant ongoing supply you may need to plan to supplement this and other nutrients, or else arrange for water turnover.....

chad duncan

Posts: 93

posted 10 years ago

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This pond is located on Vancouver Island, BC and only freezes up once every few years and has only frozen over completely once in the last five. It is fed by run off from some hayfields and horse paddocks and from a small well we pump out of. No streams or springs. This pond is primarily used for irrigating the hayfields and secondarily for sitting on the dock and drinking beer. The irrigation pump pick-up is a couple feet below the surface on a floating platform so it remains below the surface.
The hayfields are fertilized so I don't think the nutrient loss will be an issue.
I have added 50 common goldfish and 50 trout over the last couple years but they get eaten by all manner of predator so I don't know what the stocking level might be now. The pond is fairly large maybe 30'X 120' when it's full.

Su Ba

pollinator

Posts: 2167

Location: Big Island, Hawaii (2300' elevation, 60" avg. annual rainfall, temp range 55-80 degrees F)

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posted 10 years ago

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I have azolla in one of my ponds to provide shade for the fish. When it overpopulates the surface, I simply net some out and feed it to the chickens. The fish are only small mosquito fish there for the purpose of mosquito control, but they do better when the pond doesn't get too warm. Thus the azolla. Since it never gets near freezing here, I don't know if it would survive a freeze.

The azolla floats on the surface. I find it to be pleasant to look at. As I said, when it covers too much surface I net the excess out. It only takes a couple minutes. Easy. While it reproduces on it's own, it doesn't grow all that fast for me. So I don't find it to be overwhelming. I tried introducing it to my tilapia pond, but the fish ate it faster than it could reproduce.

It's never too late to start! I retired to homestead on the slopes of Mauna Loa, an active volcano. I relate snippets of my endeavor on my blog : www.kaufarmer.blogspot.com

Cristo Balete

Posts: 1041

Location: In the woods, West Coast USA

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posted 10 years ago

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I like Azolla a lot because it composts like crazy, is a great soil amendment. The birds brought it in on their feet, so it volunteered. I use a pool scooper and "harvest" it. I was glad to have it, but scooping it out practically made it disappear, so it is very easy to control. I was disappointed when I thought it was gone, but a year later it is on the edges. I had to be careful of the newts and pollywogs and frogs that were under it when I scooped, they like it a lot, so I had to go through it and get them back out.

If you do nothing it will grow and cover the surface, and even get thick, so you can't just ignore it. I haven't been able to use the duckweed that is pervasive, and I think the Azolla slows the duckweed down a bit.

Mediterranean climate, hugel trenches, fabulous clay soil high in nutrients, self-watering containers with hugel layers, keyhole composting with low hugel raised beds, thick Back to Eden Wood chips mulch (distinguished from Bark chips), using as many native plants as possible....all drought tolerant.

siu-yu man

Posts: 99

Location: zone 6a, north america

posted 10 years ago

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i really hate to be the one to bring this up, but a species of azolla is on The List:
http://extension.psu.edu/natural-resources/water/ponds/aquatic-invasive-species-water-gardens/noxious-weeds

that is not to say that if this plant just happens to find itself in your pond, that there are not multiple productive uses for it.
from the wiki link, it looks like there a multiple species in the family with only one on The List.

I think having land and not ruining it is the most beautiful art that anybody could ever want to own. - warhol

D Nikolls

pollinator

Posts: 1782

Location: Victoria BC

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posted 10 years ago

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When we had a small backyard fishpond, we introduced Azolla numerous times; it never returned the following spring without reintroduction. Duckweed, however, reliably comes back each spring, both in that pond, in our open topped concrete reservoir. Even if the reservoir runs dry, the following year the duckweed will be back.

Neither has any odor issue that I've ever noticed, nor would I call either one an eyesore. Both should be good for the inhabitants of the pond, providing food and shelter. Our reservoir is home to all sorts of critters, including TONS of treefrog tadpoles. This is particularly good because all the larger ponds nearby host much larger aquatic frogs, including the massive invasive bullfrogs; I don't think the treefrog tadpoles fare very well in mixed company, being snack-sized...

Also, siu-yu man, I really hate to be the one to bring this up, but that's the the wrong list!

Azolla is NOT listed in the BC Weed Control Act(http://www.agf.gov.bc.ca/cropprot/noxious.htm), nor the Weed Seeds Order of 2005(http://laws-lois.justice.gc.ca/eng/regulations/SOR-2005-220/page-2.html#h-4); those are the only relevant lists that I am aware of.

'Theoretically this level of creeping Orwellian dynamics should ramp up our awareness, but what happens instead is that each alert becomes less and less effective because we're incredibly stupid.' - Jerry Holkins

allen lumley

pollinator

Posts: 4154

Location: Northern New York Zone4-5 the OUTER 'RONDACs percip 36''

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posted 10 years ago

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siu-yu man and Dillon Nichols : Between the Two of you you raise a couple of very valid points ! sit-yu man is using a list from Pen State University, *

and you feel that your list specific to B.C. and the Canadian Maritimes is - for you - a better choice !

Often when you start comparing lists you will find discrepancies, even though these lists often end up locally being ''The Letter of the Law'' placement

on a list is often a matter of opinion, if a plant is invasive and in one location it provides habitat for an invasive insect, For example, then it makes sense

for that plant to be on the list for that locality !

Certainly a list specific for your locality should be a well used tool, but being aware that a plant being researched has made the list in another location

-especially where the winters are harder - Is another tool in your tool bag !

* Around here we say '' Better a Brother in the State Pen !!! - Then a sister at Penn State

For the Crafts Big AL

Success has a Thousand Fathers , Failure is an Orphan

LOOK AT THE " SIMILAR THREADS " BELOW !

Cristo Balete

Posts: 1041

Location: In the woods, West Coast USA

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chad, I'm a ways south of you, and the birds/ducks brought the azolla 3 years ago, so it's on its way up there. If you want to get the kind you'll eventually get anyway, just drive south until you find it on a coastal pond and help yourself. Maybe there are some Washington, Oregon folks here who can say whether they have it or not.

Duckweed got so bad on my pond the ducks and birds stopped coming to it. The coots would dive for food, come up with duckweed on their heads. It was sad. So in cleaning it up I tried to compost it, but it never composted. It just sat there. Luckily it can't get loose on land, so I used it. I guess it's doing some good, it's just hard to get it to mix in.

siu-yu man

Posts: 99

Location: zone 6a, north america

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Dillon, Chad : my bad, i failed to notice before that Chad specifically mentioned BC above. thus for you, "The List" is not The List, but just another useless list.

Big Al : yes, it's a Penn State link (great pun, btw) but the list is a Federal one (US), even though the US comprises a large collection of local climates. what may indeed be "invasive" in hot, humid FL may not be for you up there in the cool mountains of NY, nonetheless, both areas are subject to the same List. don't want to sidetrack the discussion, just something to be aware of, that's all.

we have some azolla here in a pond that was here when we got the place. not sure what species it is (didn't even know what it was until this thread), but, to echo Dillon's experience, it definitely suffered significant die-back during the winter and is far less aggressive in its spread than the duckweed. i agree that it's a nice looking plant.

cristo: re: duckweed -- you might want to try this method:
http://duckweedgardening.com/2014/06/10/lasagna-method-of-duckweed-compost/
i have burying it in small mounds with some wood slash in hopes that it helps break down the wood faster and the wood soaks in the nutrients from the duckweed.
i was just wondering if maybe incorporating it with char to make a duckweed biochar instead would even be a better method.

I think having land and not ruining it is the most beautiful art that anybody could ever want to own. - warhol

Cristo Balete

Posts: 1041

Location: In the woods, West Coast USA

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siu-yu, thanks for the info. I've got to say, it would be extremely satisfying to set duckweed on fire, formally or informally! Ha!

I do bury it with manure (nitrogen), and it's slow (which maybe is a good thing) but that's the only way I've gotten it to break down. That link doesn't include any nitrogen in the mix, and since duckweed is almost all cellulose, it requires a LOT of nitrogen to get it to give up. Paper, cardboard is not my favorite composting material because I think these days they include insecticides and anti-fungal components to it. 10 pounds of it with one wheelbarrow of duckweed? That's an odd combo, duckweed isn't that wet. I used to get cardboard to break down fast, but in the last 10 years or so it's a lot tougher than it used to be.

This is interesting, duckweed as biofuel:

http://www.science20.com/news_articles/duckweed_pest_has_potential_become_biofuel_powerhouse-130017

chad duncan

Posts: 93

posted 10 years ago

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For a follow up question,
Does anyone know where I could get some azolla on Vancouver island? Any ponds overflowing with the stuff?

D Nikolls

pollinator

Posts: 1782

Location: Victoria BC

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posted 10 years ago

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Cristo, we apply duckweed as mulch; no rush to make it decompose, it gets there eventually, and in the meantime can do a bit of weed suppression. Have also added to compost piles or dug it in while doing hugels/planting stuff.

If I wanted to harvest it easily on a regular basis from a mediumish pond, I'd probably seek out a couple big industrial fans, blow it to one side of the water, then harvest from there.

Chad, see here: https://permies.com/t/45586/ponds/weed-turned-pond-red#363547
I still haven't been anywhere near there to grab some...

Cristo Balete

Posts: 1041

Location: In the woods, West Coast USA

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posted 10 years ago

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Dillon, yeah, collecting duckweed is pretty easy, I just use a pool scooper. I got 3 muck buckets full today, and buried it all in a trench. Good riddance!

I am going to experiment with leaving a few piles of duckweed around, let the flies show up, and then the birds show up. It might keep them away from my blackberries.

Ci Shepard

Posts: 16

Location: Vancouver Island, BC

posted 10 years ago

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Chad, I have Azolla in some fountain planters and live in Nanaimo ... you could pick up or I can mail you some.

Deb Berman

Posts: 55

posted 10 years ago

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Theoretically, azolla, due to its cyanobacterium associate, has the potential to produce BMAA, which is a neurotoxin, although nobody seems to know under what conditions it might be prone to do that. It might be more prudent to use duckweed instead if you or animals are ever going to eat it. Duckweed as far as I know doesn't have that problem.

I have a stock tank that I grow duckweed in for my aquaponic system (fish food), and it has made such a thick mat that the water isn't really evaporating much at all, even though our temps have been stinking hot the last couple of weeks. Also, the tank isn't breeding mosquitoes anymore, as they can't get to the water surface to lay their eggs.

Did somebody else mention this link? http://theazollafoundation.org

Cristo Balete

Posts: 1041

Location: In the woods, West Coast USA

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posted 10 years ago

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But, Deb, doesn't the duckweed itself use a lot of water? It may not be evaporating, but the plants are using it and transpiring it through their leaves. Are you really noticing you use less water in the tanks?

bob day

pollinator

Posts: 823

Location: Central Virginia USA

posted 10 years ago

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I don't know much about the stuff, bought some and grew it one summer, and it did marginal, one pond di show the phosphorus deficiency by turning purple (thanks for that bit of research) and it did not automatically come back in spring, in fact, I couldn't even keep any alive in the greenhouse.

The fish loved it, and it's prettier than the duck weed, but the duck weed seems to win hands down in competition (I'm in VA, with a minimum temp of about -2 F)

If i buy any more, to play with I'll add some phosphorus to the water and see if that helps it's growth rate, as it is a plant I'd like to keep around, even if i do need to reintroduce it each year from the greenhouse.

Cristo Balete

Posts: 1041

Location: In the woods, West Coast USA

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Deb, thanks for the heads up on the BMAA neurotoxin in Azolla. Here's what Wikipedia says about it, and it's not looking good:

"Degenerative loco-motor diseases have been described in animals grazing on cycad species, fueling interest in a possible link between the plant and the etiology of ALS/PDC. Subsequent laboratory investigations discovered the presence of BMAA. BMAA induced severe neurotoxicity in rhesus macaques, including.[16]

limb muscle atrophy
nonreactive degeneration of anterior horn cells
degeneration and partial loss of pyramidal neurons of the motor cortex
behavioral dysfunction
conduction deficits in the central motor pathway
neuropathological changes of motor cortex Betz cells

There are reports that low BMAA concentrations can selectively kill cultured motor neurons from mouse spinal cords and produce reactive oxygen species.[13][17]"

https://en.wikipedia.org/wiki/Beta-Methylamino-L-alanine

bob day

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Posts: 823

Location: Central Virginia USA

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does that mean i was poisoning my fish? Is it just one species? how many other species are there? how does one differentiate?

Cristo Balete

Posts: 1041

Location: In the woods, West Coast USA

214

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Bob, according to that Wikipedia article, because Azolla uses cyanobacteria to fix nitrogen, all types of Azolla would contain the neurotoxin BMAA.

Here is an article on BMAA which seems to be recently examined for these problems, and they haven't studied it long enough to be conclusive. It mentions not only fish, shellfish, but also BMAA in the water.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3295368/

"The Emerging Science of BMAA: Do Cyanobacteria Contribute to Neurodegenerative Disease?"

"β-methylamino-ʟ-alanine (BMAA)—a cyanobacterial neurotoxin found in contaminated seafood and shellfish, drinking water supplies, and recreational waters—may be a major factor in these diseases."

Deb Berman

Posts: 55

posted 10 years ago

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Re: evaporation and duckweed -- I admit it's not scientific as I don't have a comparable tank with no duckweed in it, but I just went and looked at it and the water level is only down a couple of inches from where it was the last time it rained (maybe a month ago), and its been in the 90s or above the last 2 weeks. My impression from filling the livestock tanks and the birdbaths is that this one hadn't had the duckweed in it it would have been dry or almost dry by now. I should think it would be worth experimenting with. I'm sure it does lose some water from transpiration but maybe the humidity level right at the surface of the pond is close enough to 100% that the transpiration rate is actually very low.

Re: BMAA --My understanding is that no one is really sure what triggers cyanobacteria to produce their toxins, which is why I'm uneasy about using azolla in my systems as otherwise it's a very cool plant with lots of potential uses. If we knew what conditions could trigger toxin production we could theoretically control for them. But not knowing makes it kind of a crap shoot.

Randy Tipton

Posts: 7

posted 10 years ago

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Not sure if anyone else has posted this. Interesting guild.

http://pubs.iclarm.net/Naga/na_2359.pdf

André Troylilas

Posts: 166

Location: North of France

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posted 9 years ago

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I have several 1 cubic meter tanks to water my garden.
For the time being, I have never totally emptied them.
I (stupidly?) thought I could grow azolla or another floating aquatic vegetable in them while using the tanks for watering.
The biggest problem I see is the harvest... but there must be tons of other obvious things I haven't seen yet.
Any ideas?
Thanks.

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