Irrigation

[Somtham]

Not quite true , there is a very successful broad-acre farm growing huge amounts of potatoes situated between Sawang Daen Din and the Mekong in Issan, managed by a Kiwi .nearly fell over when I saw the size of the travelling sprinkler booms run off multipe 12 inch pumps.

What was driving the 12" pumps? 10, 15Hp 3 phase motors?

[Maizefarmer]

Beacause you see a farm somewhere growing something does not meccesaarily mean its commercially viable ................

It is (or was) an experimental exercise - sponsored with seed stock supplied by Berli Juker.

I don't what they have finaly concluded (if indeed the have got to that point yet) , but I do know that from a commercial perspective the initial results have been dissapointing.

The Thai potato farming sector is almost exclusivley to support potato crisp production - which requires a certain type of potato. If this becomes a commercial success in due course, it will be for the production of some or other type of potato, for and other than those used for crisp production.

If you go past the place again, please take a few pic's would love to see how they do over an extended period of time - which will determine the commercial viability of the project.

Tim

Pond Life

Tim tried potatoes once, and it was a complete faliure.

The fact is, unless you are in the highland region around Changmai or Changrai, you just do not have the climatic conditions in Thailands to grow potatoes successfully. There is no way way that one was his conclusion.

Not quite true , there is a very successful broad-acre farm growing huge amounts of potatoes situated between Sawang Daen Din and the Mekong in Issan, managed by a Kiwi .nearly fell over when I saw the size of the travelling sprinkler booms run off multipe 12 inch pumps.

[jimbabe]

If I didn't stick my neck out and post my original analysis I probably would not have learned as much about this device. If you had not challenged my analysis I definitely would not have learned as much about this device.

Chownah

how about hooking a kwaai to a geared turntable with pump? Same speed as water wheel but much more power. Only nee coupla hours a day and fertilizer stays in one place!

[phibunmike]

I have given a little thought to pumping water with a water wheel or similar - not a lot of thought as I haven't got a river near enough.

But one idea I had was to use windmills, similar to the ones you see on the road from Bangkok to Hua Hin, used to pump water in/out of the salt evaporation ponds.

Even is wind is not consistent, this could possibly be used to pump up to a reservoir on higher ground.

Cheers,

Mike

[Pond Life]

Yes, windmills are are great idea but unfortunatly where i live there is consistantly no wind.

There was a bit of a discussion on windmill pumps, includeing a suplier in Thailand I think.

Maybe someone could post a link if they know where to find it.

[chownah]

Thought I'd post a progress report on the alternative tank design. I've been sort of perplexed by how its been going. First I started by changing the dimensions of my tank so it was closer to a cube so it would take less materials but then I figured that the walls were so tall it would have to be buried..so I did a compromise an approximately 5m square tank almost 3 metres tall but still wasn't feeling like I could build this above ground efficiently.....and then it dawned on me that I was building WALLS to make a tank and the ferrocement people were actually builidng a cylindrical TANK. A cylindrical tank is designed completely differently from walls so I shifted gears and started looking on the internet for cylindrical concrete tanks...and finally came up with an Australian(I think) designer who build alot of tanks for the railroad there at the turn of the century (from two centuries ago to last century that is) and lots of other people....so I'm in the process of taking some of his details and concocting an estimate for a tank that should be almost identical in shape to the ferrocement tank (about 6m in diameter and about 2 metres tall).

Also, I have been scrutinizing the strength analysis presented by the ferrocement tank people and it looks like they made a mistake in the way they did it...but it is a mistake (if my assessment that it is a mistake is correct, that is) that would cause them to build the tank stronger than they would need...so its not a problem but it is somewhat disconcerting.

When I get some numbers together I'll post them.

Chownah

[chownah]

Yes, windmills are are great idea but unfortunatly where i live there is consistantly no wind.

There was a bit of a discussion on windmill pumps, includeing a suplier in Thailand I think.

Maybe someone could post a link if they know where to find it.

I've always thought someone should invent a lack-of-windmill. I think you would have to build the thing with a fan constantly blowing on it and you'd have to do it in a way so it just balanced the wind from the fan....then....when you turned the fan off it would be out of equilibrium and would start turning....and keep turning as long as there was no wind.....great idea huh.

Chownah

[Pond Life]

I think you touched on this point earlier when you said the ferrocement design looked like an eggshell.

An eggshell of course has a huge strength to weight ratio.

Until that is, it comes into contact with the edge of the frying pan, or in the case of the tank, the back bumper of your pick-up truck.

Also a sphere has the lowest surface area:vloume ratio, so needs least material.

The ferro site had alot of impressive looking calculations, but after that I think they threw in a bit of the brick shithouse concept, which might account for the over strong re-bar, a bit more pick-up proof.

That said Im probably looking at one round above ground ferro for irrigation & one or two burried poured tanks beside the house for rainwater. Im thinking approx 4.5x4.5x2 for the poured tanks to take advantage of the full lenght of re-bar. More than 2 m deep/high seems to be pushing your luck.

[btate]

Re. storage tanks.

In regard to cost, ease of implementation and simple design would not tanks similar to Slow Sand Filters do the trick? Some rings and simple plumbing should provide a controlable 'field' of storage.

The downside that I can see is the required real estate to approximate the needed volume.

I am looking at a system that would provide filtration and storage for a commercial garden I'm planning.

bt

Edited February 13, 2007 by btate

[chownah]

Re. storage tanks.

In regard to cost, ease of implementation and simple design would not tanks similar to Slow Sand Filters do the trick? Some rings and simple plumbing should provide a controlable 'field' of storage.

The downside that I can see is the required real estate to approximate the needed volume.

I am looking at a system that would provide filtration and storage for a commercial garden I'm planning.

bt

Well let's do some rough estimating...a one metre diameter concrete pipe hold about 0.75 cubic metres per metre of length and we want to store 60 cubic metres so that means we will need about 76 metres of concrete pipe and I'll estimate they will cost about 400 or 500 baht per metre so that means the pipe alone will cost between 30,000 and 38,000 baht.....I believe that Pond Life estimated he could build the tank for 40,000 baht for all the materials. Plus you will need to make a footing for them...if you build them 4 metres tall you will need to build 19 footings about 2 metres square and about 0.25 metres thick which means once cubic metre per so even without the reinforcing steel you are talking about 28,000 baht (at 1,500 baht per cubic metre)...and even if you only use half as much concrete.....well.....seems like it will probably end up costing you more than building the tank and we haven't mentioned the pipes, mortar, rebar in the footing, and the internal sealer....and...........

....NOT CONSIDERING LABOR which is an important consideration since around where I live I could easily find a crew to build the stacked rings with very little supervision while I definitely could not find a crew to build the tank. Also the stacked ring construction could be done a few at a time so if you had a limited amount of available money but more coming in then you could do it in increments.

Don't know how long the stacked rings would last but no reason why they shouldn't last as long as the ferrocement tank I guess....but it does look like they would be more expensive EXCLUDING LABOR CONSIDERATIONS.

Chownah

P.S. Check my numbers....I often make mistakes that I fail to catch later.

Chownah

[Pond Life]

I havnt checked Chowna's numbers, but it seems to me the first question is how much storage do you need ?

If you need less than say 10,000 lt then the well rings would probably work out cheaper & definatly simpler. I recently paid 180 B for 1.2 m x .4 m rings (very good quality).

If you need more than 10 k then I think the round ferrocement is hard to beat on price & the bigger you make it the cheaper per liter it gets.

[btate]

Thank you both.

I'm no good with maths (volume of liters or C meters of water)

I'm looking at a method of cleaning up a water source and using it for drip irrigation.

The Slow Sand Filter seems to be appropriate for the clean up stage. Now I need storage

for enough water to utilize roughly 4K liters per day. Three or four days of storage should

suffice.

The water is from a "pond" / swamp, that appears to be loaded with silt, weeds, and who

knows what else. The application would be for intensive production in a green house. The

target products would be one of a couple of options. Tomatoes, cantelope or maybe even

makua.

Thanks again.

Bt

[macan]

I added a link to the pinned thread on Boreholes for the WELL resources webpage.

It's run by the Water, engineering and development group at Loughborough Uni and gives access to a load of resources on water (including irrigation) and sanitation engineering in developing countries. http://www.lboro.ac.uk/well/index.htm

[chownah]

I havnt checked Chowna's numbers, but it seems to me the first question is how much storage do you need ?

If you need less than say 10,000 lt then the well rings would probably work out cheaper & definatly simpler. I recently paid 180 B for 1.2 m x .4 m rings (very good quality).

If you need more than 10 k then I think the round ferrocement is hard to beat on price & the bigger you make it the cheaper per liter it gets.

This looks like a good time to give my conclusions on my study of concrete and rebar alternatives to the ferrocement design which Pond Life brought up here.

It seems to me that a round (actually cylindrical) tank is probably the most efficient shape to build from a cost of materials stand point (excluding a sphere which would be really really difficult to built). This is primarily because virtually all of the stresses in the wall are tension and can be provided by rebar and wire hoops going around the tank. There really are no significant compressive stresses in the wall so minimal concrete is needed since concrete is used to provide compressive strength primarily.....the main function of the concrete (or mortar) in a cylindrical tank is to provide the surface that holds the water.

Early railroad era (circa 1900)elevated water tanks were cylindrical and made of steel reinforced concrete. Most of the steel was in hoops running around the wall. The concrete in the walls was thin just like in the ferrocement tank and the engineers then relied on concrete's ability to self seal the cracks that developed. They did not use concrete with only sand and no rock like the ferrocement tank but preferred to use rock or even broken bricks as mentioned in an historic letter which I found on the internet.

I think that the cylindrical shape is the way to go for efficiency of materials....especially reduced concrete (mortar). A decision needs to be made as to whether one wants to use hand packed mortar like in the ferrocement tank or whether you want to used poured concrete. Packing means no rock or only very small ones, it is for most people more labor intensive but requires no forms to be built, but it does have an added expense for metal mesh in the wall to hold up the hand packed mortar. Pouring concrete allows the use of rock and requires less labor for installation but requires forms to be built and a relatively difficult shape of form and because of this incurs an added expense.

I think that it is important to consider some other factors: expertise and labor required for design, layout, and construction. A square cornered traditional wall like tank only requires skills that are readily found in Thailand by laborers whose daily rate is low and the design is easy enough to understand that even a semi-skilled owner can easily verify if the job is being done correctly. The ferrocement tank, however is a difficult shape to build both from the laying out of the cylindrical wall and from the standpoint of placing the mortar. You will not find cheap labor capable of doing this without alot of owner instruction...and it will take an owner sophisticated enough in the geometry of the design to be able to verify that all is being done as per plan....and then there is the teaching of the hand packing techiniques...I would want to do a practice tank (a small one) for teaching purposes...add this to the expense for this tank?

And then there is the stacked ring tank which has its own set of advantages.

Chownah

[Pond Life]

BT, I think maybe youre looking at this from the wrong direction.

You said your water source is a pond/swamp, so sounds like you already have water storage.

Why pump it from a pond to a slow sand filter, then pump it again to a tank, then pump it again into the drip system ? Unless of course you have a steep site & you can gravity feed from the filter down.

Why not pump straight from the pond thru filters into the drip system.

Suitable filters would be much cheaper & easier than building a tank.

Also I dont think a slow sand filter could handle 4 k lt a day.

You could easily make a coarse sand filter out of big blue PVC pipe to take out the worst of the slime & then thru an off the shelf cartridge filter. From what i've read the drippers only need 100 micron filtration.

[chownah]

Slow sand filters are often used for municipal water systems so 4k litre per day is not a problem if the system is sized correctly....come to think of it my domestic slow sand filtering system will do that much in a day. One thing to consider is that the dirtier the water the more often the sand will need to be cleaned. I use a slow sand filter on my domestic water and it takes ground water that stinks and makes it drinkable (as indicated by gov't water test results). I have to clean the top 5 to 10 cm of sand about every 6 months. Backflush is an option but for me every 6 months is not a problem so I just do it by hand. I think that with really dirty water you should use really coarse sand so it will go longer between cleanings....maybe it would take two filtrations in series....I think its do-able but might take some tinkering and/or experimentation.

The advantage of a slow sand filter is that you don't need as much energy to get the water through the filter....and if designed properly will give drinkable water.

Chownah

[ozzydom]

Not quite true , there is a very successful broad-acre farm growing huge amounts of potatoes situated between Sawang Daen Din and the Mekong in Issan, managed by a Kiwi .nearly fell over when I saw the size of the travelling sprinkler booms run off multipe 12 inch pumps.

What was driving the 12" pumps? 10, 15Hp 3 phase motors?

All powered by diesel engines ,they sit in floating rafts tethered inthe river, 3 pumps and engines per raft with flexible couplings

[ozzydom]

Beacause you see a farm somewhere growing something does not meccesaarily mean its commercially viable ................

It is (or was) an experimental exercise - sponsored with seed stock supplied by Berli Juker.

I don't what they have finaly concluded (if indeed the have got to that point yet) , but I do know that from a commercial perspective the initial results have been dissapointing.

The Thai potato farming sector is almost exclusivley to support potato crisp production - which requires a certain type of potato. If this becomes a commercial success in due course, it will be for the production of some or other type of potato, for and other than those used for crisp production.

If you go past the place again, please take a few pic's would love to see how they do over an extended period of time - which will determine the commercial viability of the project.

Tim

Pond Life

Tim tried potatoes once, and it was a complete faliure.

The fact is, unless you are in the highland region around Changmai or Changrai, you just do not have the climatic conditions in Thailands to grow potatoes successfully. There is no way way that one was his conclusion.

Not quite true , there is a very successful broad-acre farm growing huge amounts of potatoes situated between Sawang Daen Din and the Mekong in Issan, managed by a Kiwi .nearly fell over when I saw the size of the travelling sprinkler booms run off multipe 12 inch pumps.

Maizefarmer, the viability of the project I wouldnt hazard a guess at,but I am well acquanted with the manager and he wants me to visit again when i,m free,so I will take the digital and if permitted ,get some pics for you ,will also ask some pertinant questions, last season they did a big acreage of some of the nicest sweet corn I have tasted (seed from America)but I,m led to believe transport costs and pilfering on the way to the factory was a big problem.

[ozzydom]

Right first time, Im in Mae Hongson area NW of Chiang Mai. about 500 meteres alt.

Average morning low for Dec was about 9 deg C with thick dripping mist.

Daily high 25-30 dec C, very low humidity, zero rainfall.

They definatly grow spuds round here but might be higher up the hill.

I was just wondering if there was any particular reason potatoes wouldnt like the bucket & drip system presumeing all other variables were ok.

Pond Life, a couple of tid-bits re growing spuds , they hate wet feet and are very prone to rot,that is why , when you hill them you make sure the bottom of your gutter is below your seed level. also spuds like phosphorous not nitrogen ,N gives you all top and chat spuds like marbles. Duck manure if available is the Ace fertiliser for taters.

ozzydom

[btate]

Pondlife

BT, I think maybe youre looking at this from the wrong direction.

You said your water source is a pond/swamp, so sounds like you already have water storage.

Why pump it from a pond to a slow sand filter, then pump it again to a tank, then pump it again into the drip system ? Unless of course you have a steep site & you can gravity feed from the filter down.

Why not pump straight from the pond thru filters into the drip system.

Suitable filters would be much cheaper & easier than building a tank.

Also I dont think a slow sand filter could handle 4 k lt a day.

You could easily make a coarse sand filter out of big blue PVC pipe to take out the worst of the slime & then thru an off the shelf cartridge filter. From what i've read the drippers only need 100 micron filtration.

Not being an expert I had thought the same that a Slow Sand Filter would be too slow, however, Chownah seems to have no problems at the rate of 4Kl per day.

Your correct in that removing the scum and large particulate is the primary goal. I've been told that the 'pond' never goes dry in 'dry season'. But wouldn't mind some backup just in case, at least would provide me time to convert to mains source.

The idea of in-liine filtering had crossed my mind but having no idea of pressures required/volume of the filter etc. my original idea was to use an already filteres source.

Anyway, due the quality of posts here I've learned quite a bit and now know there are several solutions at hand.

Thanks to all.

Bt

[Pond Life]

I have to concede to Chownah on the slow filter, he's got one in operation.

I thought the "slow" was the important part, for bacterial action.

Here's a good link for drip irrigation, inc flow rate, filters etc.

http://www.irrigationtutorials.com/

Maizefarmer, I think you said you used drip for makua in buckets, what filtration did you use ?

[chownah]

I think that the term "slow" sand filter has to do with the speed of the water when traveling through the filter. Compare a 10 cm diametre in line filter with a 1 metre diametre slow sand filter. With the same number of litres per hour flowing through them the speed of the water in the in line filter will be 100 times the rate in the slow sand filter.....the water in the slow sand filter is traveling much much slower. To maintain a certain level of filtration and to increase the litres per hour rate then you make the surface area of the slow sand filter bigger which for a stacked ring tank means using larger diametre rings.....or splitting the flow and using two tanks.

Chownah

P.S. Some discussion of slow sand filters and a link to a web site about slow sand filters can be found in this thread:

http://www.thaivisa.com/forum/index.php?sh...low+sand+filter

Chownah

Edited February 17, 2007 by chownah

[Pond Life]

Thanks for the tips Oz, The thing about keeping their feet dry was why I was wondering if spuds in a bucket would be a good idea.

So if duck poo is good for spuds, how about chicken ? I had a search around on the net & the only other good source of P I could find was bone meal. Where would I buy that ? is it available from fertilser suppliers ?

Are there any plants that are good for getting P into a compost heap ?

[ozzydom]

Thanks for the tips Oz, The thing about keeping their feet dry was why I was wondering if spuds in a bucket would be a good idea.

So if duck poo is good for spuds, how about chicken ? I had a search around on the net & the only other good source of P I could find was bone meal. Where would I buy that ? is it available from fertilser suppliers ?

Are there any plants that are good for getting P into a compost heap ?

I have a list of P content of the different animal and bird droppings on a memory stick courtesy of the Fisheries Dept, I will look it up and post it.

P to the best of my knowledge is naturally occurring in soil and is an essential element in plant growth but the main source is guana and superphosphate which is approx 21% P, triple super is about 46%.

The P in duck and chicken dropping is almost immediately available whereas cow poo has to break down to release it, in both compost and in water the organisms use up heaps of N so you need to give whichever environment a dose of Urea to maintain N content.

Bone meal and blood and bone is available but its hellishly expensive, good fish food contains it to get the protein content up, thats why we pay 20bt a kg for the pellets

[Khonwan]

Thanks for the tips Oz, The thing about keeping their feet dry was why I was wondering if spuds in a bucket would be a good idea.

So if duck poo is good for spuds, how about chicken ? I had a search around on the net & the only other good source of P I could find was bone meal. Where would I buy that ? is it available from fertilser suppliers ?

Are there any plants that are good for getting P into a compost heap ?

I used to buy (3/4 years ago) bags of bonemeal from a shop called Puan Cobaan, in Kampaengsen, near the agricultural university (tel: 034-351831, 352614 ). I don't recall the bagged weights but I have recorded my purchases as costing 6 baht per kg. The shop specialises in products and feeds for beef cattle - I rate it highly. Their English is poor so ask for "gadook bone" (bonemeal).

[chownah]

You don't need to add urea or any other chemical fertilizer to compost.

[ozzydom]

You don't need to add urea or any other chemical fertilizer to compost.

A bland statement chownah ,nobody said you have to ,it just helps the micro-organisms do their job better as they are nitrogen guts and you will achieve composting quicker.

In water you do need it or you will get oxygen depletion in your pond.

[chownah]

You don't need to add urea or any other chemical fertilizer to compost.

A bland statement chownah ,nobody said you have to ,it just helps the micro-organisms do their job better as they are nitrogen guts and you will achieve composting quicker.

In water you do need it or you will get oxygen depletion in your pond.

Actually YOU said that you have to...specifically you said, "the organisms use up heaps of N so you need to give whichever environment a dose of Urea to maintain N content.".....doesn't the word "need" mean "have to"?....that's how I usually interpret it.

I suggest you go out on the internet and read about the carbon/nitrogen ratio and its importance in understanding the dynamics of composting. I think that you would see that you need to qualify your statements more for them to be appropriate...at least I think you would see that.

You don't need to add chemical nitrogen to avoid oxygen depletion in a pond generally speaking. Perhaps if you qualified your statement a bit it would make sense but to just make the general statement is obviously not correct for all situations....some ponds do just fine with no human intervention at all and THEY are not oxygen depleted for example.

Chownah

Edited February 17, 2007 by chownah

[ozzydom]

You don't need to add urea or any other chemical fertilizer to compost.

A bland statement chownah ,nobody said you have to ,it just helps the micro-organisms do their job better as they are nitrogen guts and you will achieve composting quicker.

In water you do need it or you will get oxygen depletion in your pond.

Actually YOU said that you have to...specifically you said, "the organisms use up heaps of N so you need to give whichever environment a dose of Urea to maintain N content.".....doesn't the word "need" mean "have to"?....that's how I usually interpret it.

I suggest you go out on the internet and read about the carbon/nitrogen ratio and its importance in understanding the dynamics of composting. I think that you would see that you need to qualify your statements more for them to be appropriate...at least I think you would see that.

You don't need to add chemical nitrogen to avoid oxygen depletion in a pond generally speaking. Perhaps if you qualified your statement a bit it would make sense but to just make the general statement is obviously not correct for all situations....some ponds do just fine with no human intervention at all and THEY are not oxygen depleted for example.

Chownah

As I recall from a couple of years back ,the leopard hasnt changed its spots,you are still a know all chownah, when you successfully farm 50,000 fish then advise me about the game , one day somebody may take notice of the rubbish you sometimes post so authoratively with catastrophic results to themselves and their business. No further correspondence will be exchanged with you.

ozzydom

[chownah]

You don't need to add urea or any other chemical fertilizer to compost.

A bland statement chownah ,nobody said you have to ,it just helps the micro-organisms do their job better as they are nitrogen guts and you will achieve composting quicker.

In water you do need it or you will get oxygen depletion in your pond.

Actually YOU said that you have to...specifically you said, "the organisms use up heaps of N so you need to give whichever environment a dose of Urea to maintain N content.".....doesn't the word "need" mean "have to"?....that's how I usually interpret it.

I suggest you go out on the internet and read about the carbon/nitrogen ratio and its importance in understanding the dynamics of composting. I think that you would see that you need to qualify your statements more for them to be appropriate...at least I think you would see that.

You don't need to add chemical nitrogen to avoid oxygen depletion in a pond generally speaking. Perhaps if you qualified your statement a bit it would make sense but to just make the general statement is obviously not correct for all situations....some ponds do just fine with no human intervention at all and THEY are not oxygen depleted for example.

Chownah

As I recall from a couple of years back ,the leopard hasnt changed its spots,you are still a know all chownah, when you successfully farm 50,000 fish then advise me about the game , one day somebody may take notice of the rubbish you sometimes post so authoratively with catastrophic results to themselves and their business. No further correspondence will be exchanged with you.

ozzydom

Anyone who takes my posts as the final authority on any topic is showing bad judgement in my opinion. As I said before...some people just don't like being questioned about what they post on the internet...but really none of it should be accepted without thorough questioning.

Chownah