Irrigating Cassava?

[somo]

I am interested in exploring the possibilty of irrigating cassava and wondered if anyone had looked into it.

Next year I hope to have a resevoir of water on my 25 rai patch of land most of which is planted with cassava.

I have read reports that irrigation during the dry season could double the yeild and this would also mean I can harvest and replant at any time of the year.

My intial idea is to pump a natural supply of water into storage tanks then use high powered sprinklers to deliver it but really have no knowledge of the equipment available/needed or if the cost would outway the benefit.

I think a drip feed system might be too expensive to set up and maintain and inconvenient when ploughing the land.

Any thoughts/suggestions most welcome.

[Maizefarmer]

Its going to cost a bit to set up irrigation for 25 rai - and if you use impact spinklers you'll have to run a fairly decent pressure (4bar at least - but idealy 6 plus) to get decent distrabution across the sprinkler radius - and that means fuel costs, unless you can set the pump up to run on 3 phase ac which is much cheaper to irrigate with than diesel.

All in all, irrigating cassava to increase the yield and raise your margin is hit and miss. I irrigate cassava every dry season, but what justifies that extra cost is the offset it would other cost me to purchase cassava as cattle feed. So, yes if you are feeding livestock, it can be justified, otherwise as said, it's going to be hit and miss, and on balance, nope I don't think it's worth it.

[somo]

Thanks Maizefarmer.

I am in 2 minds as to wether it is worth while but have heard of bumper crops if irrigated in the dry season.

Saw a program on TV about a lady who gets 20-30 tons/rai. Saw the tubors too - they were massive. She has drip feed on about 50 rai which must have cost a bit to set up but guess might be cheeper to run. Not sure how she manages harvesting and ploughing with all those pipes to move around but I suppose being only once a year it might be OK.

I don't much about it but does drip feed take a lot of maintenace? Can you use long runs like 300 metres without too big a pressure drop?

I guess with all those nozzles they must need checking and cleaning regularly. What i like about drip feed is that it iswould be easy to feed some fertilizer into the system.

Maybe I'll try it on 1 or 2 rai next year and see.

Steve

[Maizefarmer]

Effective drip irrigation is not as simple as it may first appear, but it is potentialy viable if certain criteria can be met.

First of all you need to be able to store x amount of water per rai/per time period to get whatever crop mass is required to justfiy to capaital layout cost.

of issues in the above sentence: your capital outlay is in proportion to the size of the field, and the larger the area to be drip irrigated the cheaper it becomes. Depending on the length of the field and hence the layout of the drip lines you need to choose drip lines that are going to be of sufficient diameter so as to aviod excessive presure drop across their length. Most decent drip lines self regulate i.e. so long as you can supply a certain amount of water at a certain pressure, and keep the drip line to its reccomended max length, al the drippers along it will delivery the same amount of water - despite the fact that the drippers at the start have more pressue avalible then the drippers say 300m - 400mm down the other end of the line.

Thats not a problem, the problem is: setting up and storing water for 25rai at sufficent height above the field - either you have land high enough above the cassava field to store water (?) and are willing to invest in dam construction, or you are going to have to build storage tanks on stilts. I'd guess you would want 3m to 5m above the cassava field to generate the line pressure required to regulate drippers over a 300m length or so. How much are you going to have to store for 25 - 30rai? I'm guessing if you work along the lines of 4l-5l per plant per hour and run the drippers for 5hrs each day (when required) - say 20 litres per cassava plant per day. Work out how many cassava plants per rai and x 25rai - theres your figure. Would somewhere between 20 000 - 50 000litres per day be a reasonable figure(?)

You big advantage with drippers is that they don;t waste water - they measure it out fairly accurately and apply it right at the plant, and you don;t need to run a pump constantly (so long as you have sufficent storage height), so you can save substantialy on energy costs.

Your downside is, the investment that has to be made in storage, pump to get the water out of wherever it comes from originally. Oh - and the disc filter - you will need a suitable disc filter, otherwise one by one the dripper outlets will block up - all the dripper lines I have ever tried (and I have tried many different types from all sorts of manufacturers, never last more than 3 or 4 seasons max - so thats another cost that has to be forked out for every few years), and they are not cheap in Thailand.

All in all, do you calculations and think through the issues very carefully before throwing money at it, but yes, if you are wanting to irrigate, I would concurr that drip irrigation would be the way to go...... and then hope like hel_l it doesn't rain madly the first season you install your irrigation system (sods law!), because not only will the irrigation system sit ideal, the market price of cassava will be low as well.

PS - make sure the dripper spacing on the drip line coincides with the cassava plant spacing

[soidog2]

I am interested in exploring the possibilty of irrigating cassava and wondered if anyone had looked into it.

Next year I hope to have a resevoir of water on my 25 rai patch of land most of which is planted with cassava.

I have read reports that irrigation during the dry season could double the yeild and this would also mean I can harvest and replant at any time of the year.

My intial idea is to pump a natural supply of water into storage tanks then use high powered sprinklers to deliver it but really have no knowledge of the equipment available/needed or if the cost would outway the benefit.

I think a drip feed system might be too expensive to set up and maintain and inconvenient when ploughing the land.

Any thoughts/suggestions most welcome.

It absolutely does not pay.

We grow cassava on over 100 rai, learned the hard way ; the only way to make a profit is to keep expenses low.

By the time you set up the system , pay for the extra labor of removing it and reinstalling it at harvest time, you will have eaten your profit on 25 rai for a while.

I never tired it myself but we are surrounded by other farmers eager to make more money.

I have watched at least ½ a dozen setups ( such as you describe ) fold after the one year.

As MF said, it will probably rain after you finish. !!

[xerostar]

I had considered irrigating too because termites attack our cassava

when the weather is very dry.

I figured that keeping the ground moist will supply the termites and

they'll stay away from the cassava.

That's only a theory of course.

Drip feed has proved troubesome with blocked drippers mainly due

to evaporation and calcium salts building up in them.

Also the quality of the drippers we bought was very poor.

They were hard to adjust and often fall apart in the hand.

The best design that I could envisage would be a grid of deep underground

4" pipes with 2" risers at 3 Metres high for the sprinklers.

A system of solenoid valves to automate the water distribution.

The tractor drivers would need to be vigilant so as to not damage the system ..

Ah.. no I forgot, on second thoughts not possible in Thailand.

Figure on regular, major repair costs as well.

The initial cost could be justified over time, but the cost of pumping the water

at high pressure would be the major obstacle.

The economics (at this time) seem to favour keeping costs as low as possible,

as already mentioned.

[somo]

Thank you all for the input.

Pretty much confirms my suspicion that it would be more hassle/expensive than worthwhile.

May still give it a go on 1 rai just to see how much tonnage I can get but too late for this year.

[finner]

Somo

First off, I'm not a farmer but have tons of experience with running through Cassava fields with the HASH club and know that in the lower lying sections of the fields the roots are decidedly (2-3x) larger than the higher sections.

I'd sure like to give you some good news about your irrigation but have only seen frustrating results. Forget drippers or spray heads. I can 99% guarantee that whatever system you put INTO or ON the ground will be torn out very quickly. We had some luck with Oil Palms by digging small trenches the length of the field and just flooding it on a daily basis. No pump involved except from the reservoir to the holding tank.

This is OK with a crop that has wide enough spacing for a truck or tractor between rows but you may still be able to do it if your land slopes enough. Most Cassava I've seen is on sloping land and the only thing you'd have to worry about is erosion. Just a thought.

25 Rai. Maybe some sort of overhead system that wouldn't be affected by harvesting equipment?

[somo]

Hi.

Thanks for your thoughts.

I have to say I would go flippin' mad if I caught you lot running around in the middle of my cassava!

[soidog2]

Hi.

Thanks for your thoughts.

I have to say I would go flippin' mad if I caught you lot running around in the middle of my cassava!

Somo, I remembered last year you were asking about the government cassava price guarantee.

Hopefully this year you caught it.

You need to sign up right now for pulling Jan/May next year.

The scheme is much more attractive than last year. For up to 100 tons per grower, the government is guaranteeing 1.70 Baht for Jan/May period.

If the mill price is lower than 1.70 Baht ( 30% starch ); on the month you picked for pulling, they will automatically deposit the difference in your agriculture bank account ( you opened one right ? ) regardless of whether you pull or not .

When you register you need to pick a pulling month in between the given dates.

Best regards.

PS, some flood insurance is also available.

Edited October 20, 2009 by soidog2

[WatersEdge]

Here is an Excel calculator,

based on current Thailand retail component prices

Plug in the number of Hectares you want to irrigate,

in the yellow cell F5

The Rai equivalent is shown in H5

A couple of explanatory notes.

Simplified for the field on square,

4" PVC Mainline through the center,

with permanent set sprinkler lines either side

See the graphic to the right of spreadsheet calculations

last 100 meters of any sprinkler line 2" PVC

and remainder of sprinkler line length 3" PVC

2" PVC Risers 2 meters high,

with lines buried 0.50 meter

Net sprinkler height 1.50 meter

I now use the more expensive 2" PVC risers

because I am tired of replacing eucalyptus support stakes for 3/4" risers.

Termites don't eat PVC yet...they are studying it.

Sprinkler pattern is

20 meters between sets,

10 meters between sprinklers on the sets

5 meter offset on adjacent sets.

In this spacing you can get complete coverage with a sprinkler radius of 11 meters,

which is possible at around 2 to 2.5 bar, 30-35 psi.

The Super Products RC-160 plastic body sprinkler will stop turning at high pressure.

Can't say exactly what that pressure is, maybe 4 bar 60 psi, but I've seen it happen on mine.

Electric Pump will certainly be cheaper than Diesel,

I run diesel because my farms do not have electricity.

Depending on the amount of water you need to apply in a given time period,

you can specify your own electric motor,

replacing my figure for Diesel Engine

Bear in mind this is a simplified ideal case.

There's a bit more to it when you have a look at your real field.

It would be helpful to know the dimensions of your field,

as they are very seldom perfectly square.

It's also important to know elevation difference,

and how that elevation difference happens in slope.

The location of the water source is also necessary.

If a given sprinkler line has a large elevation difference,

the low elevation sprinklers will put out more water due to higher pressure,

while the high elevation sprinklers are starved for pressure and put out less water.

It is most energy efficient to run a small amount of water a long time,

steadily covering the field in continual operation

rather than push a large volume of water through your lines at once.

As larger fields are considered, larger pipe size is an obvious upgrade.

Refinement is in the details...so I know there will be followup questions.

Sprinkler_System_Calculator_Diesel_20091021.xls

[somo]

WatersEdge, Thanks for the detailed info.

For now I have decided to not irrigate as the consensus seems to be that it isn't worth it for cassave but I will experiment next year with just one rai and think again depending on results. Will file all your info for future reference.

Steve

[somo]

Hi.

Thanks for your thoughts.

I have to say I would go flippin' mad if I caught you lot running around in the middle of my cassava!

Somo, I remembered last year you were asking about the government cassava price guarantee.

Hopefully this year you caught it.

You need to sign up right now for pulling Jan/May next year.

The scheme is much more attractive than last year. For up to 100 tons per grower, the government is guaranteeing 1.70 Baht for Jan/May period.

If the mill price is lower than 1.70 Baht ( 30% starch ); on the month you picked for pulling, they will automatically deposit the difference in your agriculture bank account ( you opened one right ? ) regardless of whether you pull or not .

When you register you need to pick a pulling month in between the given dates.

Best regards.

PS, some flood insurance is also available.

Thanks soidog2

This is getting confusing. We have the bank account and have signed up through the village boss but it sounds different to what you have.

WE just had to specify how much land we had under cultivation and I had no idea it was just for a limited period early next year or limited to 100 tons which doesn't seem much.

Is there somewhere I should go independently to register? Not being there all the time I just go with what I am told which is that yes we are registered for 40 rai but have no paper work confirming that.

Not sure it will be relevant as I don't intend harvesting until late next year.

As a matter of interest the market price just hit 1.70 locally so lets hope the gov. subsidy becomes irrelevant smile.gif

[WatersEdge]

I recommend to use clean water first to a fish pond,

then pump from the deepest water in the pond,

pulling the foulest most oxygen depleted water out

to the sprinkler crops.

Fish Ponds with significant water replacement can be more heavily stocked.

My general understanding of Cassava is that it will survive dry conditions,

but will fully utilize any water and nutrients that come its way.

taking advantage of the rainless growing season that otherwise passes in neutral

If part of your water costs are offset by fish pond profits,

then there are less costs to be recovered from the field crop.

Of course, nitrogen hungry crops like

Corn,

Cassava and

Sugar

respond nicely to the most unbearable fish water.

My fouled fish water does one more potential duty on the way to the field,

flushing the hog barn gutter,

but not going through the sprinklers in that case.

Level water retention contour trenches are cut into the sloped field,

below the level of the hog barn gutters.

At the end of the hog barn,

a settling sump for fibrous

cob, silage and grass residue,

to settle from the liquid portion

If you feed hogs only grain or bagged feed,

with only small non ditch clogging particles,

then it all flows directly to the trenches.

Barn cleaning labor costs are now trimmed to a fraction of previously.

and there is very little lag time of manure accumulating in the hog corral.

Laborers simply dump all the manure into the gutter,

and it all flows to the sump,

where the clogging material is forked aside,

to allow the slurry liquid to continue to the field.

With water hoses to wash the corral waste into the gutter,

labor will be reduced a bit more.

It's safe to say that the cost of water

flushing from pond through barn to field is

completely recovered by manual labor savings,

with a handsome margin to spare

There is one catch during rainy season,

when field crops don't need more water.

What does one do with all the foul fish water and pig waste then?

I do let some a little fish water flush downstream at that time,

and pig waste accumulates a bit at the barn.