Water Lettuce

[lingling]

We have a pond connected and a bunch of water canals in our countryside garden. There is not much vegetation in either thanks to way too much fish (although there is plenty of sticky slimy algae in the canals). This weekend I planted some water lettuce all over the place. After I planted it, my father in law suggested that it may not be a good idea because they will spread and cover everything in no time at all, that it will make the water "black" (stagnant) and that it will make the water "itchy".

After a bit of googling (I guess I should have done that before planting) I have found two opposing stories: the one where it will cover the surface, preventing sunlight and oxygenation. The other one where it consumes nutrients, preventing algae blooms etc.

Now, if we try to keep it somewhat under control (fishing out excess water lettuce if the fish won't eat them faster than they spread), is it a mistake to have water lettuce in the pond or is it a good plant for reducing the amount of nutrients etc?

Edited November 6, 2006 by lingling

[teletiger]

Lingling,

water lettuce makes great food. Problem is that the fish can't get to it. they tend to munch the roots which stops the plant from growing. You need to grow it in a seperate shallow pond, with loads of manure, then fish it out, mince it up and feed it. I tried to find the nutritional value of water lettuce and failed. If it's anywhere near duckweed and I suspect it is, it's great. Duckweed is 45% protien and (with enough manure fertilizer) will double its weight every 3 days. In China they run a system that produces 11 tons (dry weight ) per hectare of duckweed. They feed it to cattle and fish.

I'll try to find some of the appropriate sites.

Regards

Edited November 7, 2006 by teletiger

[lingling]

That is great - we have a bunch of cows so if it can be used to feed them then that's just perfect. I googled "Pistia stratiotes" and cattle but haven't found any useful info on its use as cow food yet... If you find any links please post them here.

[Maizefarmer]

TT - just run this through again: it can double its wieght in 3 days!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

And the protein content is way up circa 30% - 40% (even if half that it would be brilliant)

I know sweet nothing abou this as a viable forage crop.

What are the issues?

You need a pond, you need follwoing water - what else?? - and it produces what an excellent forage (??)

Any downside to using it as a base for regular feeding.

I could be digging a very large hole - I get the impression depth is not an issue - correct?

I AM ALL EARS - this sounds just to cool to be true (go on - wheres the catch!!)

Thanks

Tim

Edited November 7, 2006 by Maizefarmer

[lingling]

Apparently mosquitos like to breed in them, and the fish can't eat the larvae when they are inside the water lettuce. So maybe mosquito risk...

Here's an article about using it as pig food:

http://www.cipav.org.co/lrrd/lrrd14/1/ly141a.htm

[lannarebirth]

Biomass doubles every two days?

http://www.fao.org/ag/AGAinfo/resources/documents/DW/Dw2.htm

[Maizefarmer]

Thanks guys - I need to look through all that.

One has the impression in mind that "land" is required to grow foarge crops.

The idea of using water instead is somewhat alien, and has missed me complelty to date.

Tim

[lannarebirth]

Apparently mosquitos like to breed in them, and the fish can't eat the larvae when they are inside the water lettuce. So maybe mosquito risk...

Here's an article about using it as pig food:

http://www.cipav.org.co/lrrd/lrrd14/1/ly141a.htm

"A major benefit of using duckweeds is emerging. There is accumulating evidence that duckweeds release compounds that have insecticidal properties particular to the larval stages of mosquitoes. Thus the development of duckweed aquaculture in the wet tropics may have implications for mosquito control in rural areas where malaria is again becoming a serious problem."

http://www.fao.org/ag/AGAinfo/resources/documents/DW/Dw2.htm

[teletiger]

TT - just run this through again: it can double its wieght in 3 days!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

And the protein content is way up circa 30% - 40% (even if half that it would be brilliant)

You need a pond, you need follwoing water - what else?? - and it produces what an excellent forage (??)

Any downside to using it as a base for regular feeding.

Thanks

Tim

Tim,

If follwoing water was meant to be flowing water....then no, it needs still water. Max 45% protien (with adequate fertiliser), and a very low fibre content, as in nearly zilch.

regards

[Maizefarmer]

Yes - my spelling is absolutely useless as I'm always typing to fast - interesting to know that still water is required - which means a pond cum dam would be perfect and seems to be a great more productive use of area than is land/soil.

I need to chew this over carefully - at first glance and doing some quick mental math, potentially it represents a huge saving in cost of forage production copared to cost of producing on land - not to mention energy costs incurred in harvesting. Oh hel_l, right thorugh the whole process the figures look very attractive indeed.

And if anyone has the time on there hands I would seriously consider paying them to go away and research the subject for me. Ironicaly me old nemisis Chownah would on the face of it be the best guy to tackle that. PM me ifinterested in a bit of research work, you seem to know how to use the net rather well (mmm... my cows will be dead within the week!).

No seriously, this subject has got me real interested.

Tim

[Issangeorge]

Anybody know the name of water lettuce or duck weed in Thai, so I can ask my wife about them and then be told all that is wrong with growing them. Thanks. Issangeorge

[teletiger]

My wife says Joh (jaw)......and nair.....meaning tiny.

Regards

[chownah]

TT - just run this through again: it can double its wieght in 3 days!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

And the protein content is way up circa 30% - 40% (even if half that it would be brilliant)

You need a pond, you need follwoing water - what else?? - and it produces what an excellent forage (??)

Any downside to using it as a base for regular feeding.

Thanks

Tim

Tim,

If follwoing water was meant to be flowing water....then no, it needs still water. Max 45% protien (with adequate fertiliser), and a very low fibre content, as in nearly zilch.

regards

I found a great link on bloating in cattle and it indicated that the more quickly a forage could be broken down the more likely it was to cause bloat....with no fibre content and small leaf size I'm thinking that it could be broken down very quickly.....perhaps it could be mixed with a more fibrous material (straw) to help solve this problem...if it really is a problem. One interesting thing is that it appears that you could manipulate the mineral content by adding minerals to the water it grows in so this might be a way to deliver trace minerals....but don't know for sure...just theoretics.

Chownah

Maizefarmer,

Thanks for the offer of a research grant but I'm full up with projects already.

Chownah

[Maizefarmer]

Not to worry - I done a bit of snooping around and all is not as striaghtforward as it intiially appeared, but none the less, it is still a very interesting forage option and I am not dismissing it yet.

Tim

[Crushdepth]

I'm not sure which plant you mean, but if it is the water hyacinth (salvinia) - the thing that floats down the river in big green clumps it is an invasive species that will grow prolifically to cover ponds. As they block the light, they also reduce the plankton/natural productivity of fish ponds (so you don't really want a heavy infestation in a fish pond).

It is generally regarded as a serious pest of waterways and wetlands, but it is also often used to remove excessive nutrients from ponds (at least here in Bangkok!). Sometimes bits of pvc pipe are put together to form a simple floating 'square' shape anchored out in the middle of the ponds to keep the plants together in a manageable clump - but eventually it gets out.

Pretty hard to get rid of so if you don't already have it in your area best avoid it! I have heard of people feeding pigs with it, don't know how successfully.

[Maizefarmer]

Chownah

The other common fresh forage crop that is lethal to cattle - and which they will consume in huge quantities to death if given the chance is Lucerne. In fact it is more lethal than alfalfa.

Lucerne is grown in Thailand as a forage crop - more so in the South than the North or North East.

Notice - the physical symptom is "bloat" and it occurs only with legume crops - well, it can occur with grass chop in theory, but in reality you are going to associate it with the consumption of wet and green legume crops. Poisoning is not restricted to legumes.

Death from bloat or poisoning in Thailand is often misdiagnosed - the surest way to confirm is get the liver out: in cases of bloat death the liver will appear quite normal, however in cases of toxicity the liver will have a greenish/yellowish hue to its surface or a browish/yellowish hue to the surface.

Tim

[chownah]

I thought that lucerne and alfalfa were the same thing unless you are refering to the city in Switzerland......Alfalfa, Switzerland....its not very well known.

Chownah

[Maizefarmer]

Lucernes & Alfalfa are legumes.

Lucerne is a cultivar

Not all Alfalfa is Lucerne - there are about 10 different cultivars of Alfalfa

Amongst prrofessional farmers a clear distinction is recognised between the cultivars.

Not all cultivars of Alfalfa are used as forage crops and of those that are, not all present a health risk to cattle when eaten fresh/green.

In the first instance I was referring to Alfalfa as a lot of farmers would recognise it as been distinct from Lucerne - perhaps I should have made that clear

This of course is the differance between understanding a subject as opposed to reading it on the internet. Just what did your comment add to the discussion (and how does Switzerland come into it?)

Tell me, do you do this deliberately to piss people off or is it really just that you have nothing better to do with your time than make an issue out of a point whenever you can?

Tim

[chownah]

Maizefarmer,

I thought that the terms "lucerne" and "alfalfa" were used to mean the same thing so when I saw that you seemed to be making a distinction between them I went to google to find the definition for lucerne and found this:

"

alfalfa: important European leguminous forage plant with trifoliate leaves and blue-violet flowers grown widely as a pasture and hay crop

wordnet.princeton.edu/perl/webwn

"

I guess I am not the only one who thinks that lucerne and alfalfa mean the same thing. It was news to me that professinal farmers use the term lucerne generally to indicate a particular cultivar of alfalfa.

In your post number 61 in the Raising Beef Cattle In Issan thread you posted:

"..........

Alfalfa does not grow well by its self in Thailand - and I would certainly not grow it as a crop, as the inputs are too high versus what it has to offer. But - yes, cows love it and will consume it fresh in suicidal quantities if they get the chance. They have know appreciation that what they are eating will lead to their death over the next day or so.

...........

Alfalfa is very much an example of a cultivated forage that that a cow will feed on naturally to its detriment (i.e,. death). That is not where th risak lies in Thailand, but it can lies in naturally occuring forage growth and in uncultivated fields:"

From this I though that you were saying that all cultivars of alfalfa would cause bloat and that there are no cultivars of alfalfa that pose a risk in Thailand. My uncle has indicated that corn fields can pose a bloat hazard to cattle in Thailand...and now you are saying that alfalfa (specifically the "lucerne" cultivar) is being cultivated in Thailand as a forage crop and is a possible cause of bloat in Thailand. So I guess then that there are two cultivated crops that have the potential to cause bloat in Thailand but so far no one has indicated any particular plant species that grow in a natural Thai environment which pose a bloat danger. My uncle has already indicated that the natural plants that grow around where I live do not pose a bloat risk nor do they pose a poisoning risk...all of his views are based on this having raised cows here locally and in his experience never having seen those problems.

Also, I am not the topic being discussed here. If you want to ask questions like:

"Tell me, do you do this deliberately to piss people off or is it really just that you have nothing better to do with your time than make an issue out of a point whenever you can?"

then please do so in a PM to me. I think that it is rude to make such comments publicly and is probably of little interest to other readers and is certainly off topic.....however I don't mind you asking these questions and will gladly answer them if you ask them in the PM.

Sincerely,

Chownah

[teletiger]

You are both well off topic here Chownah. Look up at the thread heading. Start a new one, if you feel you have to

Regards

Edited November 9, 2006 by teletiger

[chownah]

You are both well off topic here Chownah. Look up at the thread heading. Start a new one, if you feel you have to

Regards

I agree. Back on topic. It seems that bloat in cattle is at least in part caused by them eating forage that has small and easily digested leaves. Since water lettuce has small leaves with no fibre content it is probably quickly broken down in the rumen and might be a bloat hazard. If someone wanted to try it on a cow as an experiment I would start with a small amount and keep an eye for bloat symptoms.

I did find a link for an experiment where water lettuce was fed to chickens with different batches of chickens getting different percentages of water lettuce in their diet from very low (I think it was 5%) up to 20%. There result was that 10% was the regimen that gave the best results.

Chownah

[teletiger]

You are both well off topic here Chownah. Look up at the thread heading. Start a new one, if you feel you have to

Regards

I agree. Back on topic. It seems that bloat in cattle is at least in part caused by them eating forage that has small and easily digested leaves. Since water lettuce has small leaves with no fibre content it is probably quickly broken down in the rumen and might be a bloat hazard. If someone wanted to try it on a cow as an experiment I would start with a small amount and keep an eye for bloat symptoms.

I did find a link for an experiment where water lettuce was fed to chickens with different batches of chickens getting different percentages of water lettuce in their diet from very low (I think it was 5%) up to 20%. There result was that 10% was the regimen that gave the best results.

Chownah

Hmmm....not sure we're all sitting at the same table here.

This is water lettuce.

Duckweed is the very small, (smaller than a 1 Baht coin) round leaved plant.

I failed to find the nutritional values for water lettuce. Duckweed is the high protien low fibre plant.

Regards

[Crushdepth]

Some info about the nutritional value of duckweed in an article Demise of waste-water fed duckweed-based aquaculture in Bangladesh (sorry about the title!).

[chownah]

Yes, my mistake...having looked back over the thread I should have said that duck weed having small leaves and no fibre might be a hazard for cattle bloat. Sorry for the confusion.

Have you found the sites that talked about duck weed being raised in China and fed to cattle?

Chownah

[teletiger]

Yes, my mistake...having looked back over the thread I should have said that duck weed having small leaves and no fibre might be a hazard for cattle bloat. Sorry for the confusion.

Have you found the sites that talked about duck weed being raised in China and fed to cattle?

Chownah

Not yet.....but here's a very comprehensive site for duckweed used as fishfood.

http://www.p2pays.org/ref/09/08875.htm#Nutritional%20value

Duckweed is also very high in trace minerals

Regards

[teletiger]

There you go.....

http://www.cipav.org.co/lrrd/lrrd7/1/3.htm

Here's a few more.

This ones for feeding Tilapia

http://www.fishfarming.com/recirc.html

Another with lots of links.

http://www.ecosyn.us/ecocity/Links/My_Link...uckweed_01.html

Seems I got my figures wrong about crop per hectare. One place in the southern US, under optimal conditions, got 79 (seventy nine) tonnes dry matter per hectare. .

Regards

[lingling]

Follow-up: we left the water lettuce in place in the pond. At first the amounts were increasing, but once the fish got hang of eating them they quickly disappeared. There are just a few odd ones left, the rest turned into fish food.

We also have water lettuce in a smaller pond (where the gray water from the septic system comes out) - less fish there so that one has to be cleared every now and then. I try to keep it at 50% surface covered by water lettuce, 50% open.

[Pond Life]

Im very interested to hear youre putting greywater into a pond.

Sounds like the water lettuce like it.

How big is the pond, are you mixing clean water with the grey, does it smell bad at all ?

You said the greywater came from your septic system, do you mean water from sinks,shower,washing machine or do you mean what floats off the top of your septic (sh1t) tank ?

Are you feeding the lettuce from the grey water to the fish in the big pond ?

[lingling]

Im very interested to hear youre putting greywater into a pond.

Sounds like the water lettuce like it.

How big is the pond, are you mixing clean water with the grey, does it smell bad at all ?

You said the greywater came from your septic system, do you mean water from sinks,shower,washing machine or do you mean what floats off the top of your septic (sh1t) tank ?

Are you feeding the lettuce from the grey water to the fish in the big pond ?

That pond is an extension of the septic system, so it gets whatever comes out the other end of the septic tank. All drains in the house (toilet, shower, sink etc etc) goes to the same septic tank, a 2 chamber 1600l thing. The "after-tank" system consists of: first a 5-6 m long, 0.5-1m deep, 1m wide canal with various aquatic plants, then a 4x6m 2m deep pond with water lettuce.

I have moved some water lettuce from the "dirty" pond to the "clean" one - that's how I got water lettuce in the big pond to start with, but the main idea is that I can turn them into [nutrient rich] compost. So far, all excess water lettuce has either ended up in the big fish pond, or on the ground next to the small ("dirty") one.

To be honest, the system hasn't been in use long enough to know if it is successful but the idea is that the aquatic plants and algae should be enough to take care of the excess nutrients in the gray water and any excess aquatic plants can then become compost.

[Pond Life]

Im impressed, I've been gathering info on greywater & rainwater collection but hadn't considered doing anything with blackwater.

Whats the water like as it comes out of the septic tank, smelly at all ?