How Many Rai Can Be Irrigated From A Good Water Source?

[Nepal4me]

I have spent a great deal of time going through the rubber tree threads, reading the bore hole threads and the irrigation threads. Tons of great info and am learning lots but I still don't know how much land can be irrigated from one source. There was so much info that I still don't know what type of irrigation and pumping system to use.

We have a plot of land (40 rai) with a man-made pond in it. Pond size is about 1 rai. It's deep as hel_l too I'm told (haven't swum in it so not 100% sure about that. Tons of water in there year round.

If somebody would respond to the followig, I'd appreciate it:

1. The pond is at the narrow end of the plot. The plot is about 200M x 300M. Very flat land. Would it be practical to pump water out of this pond to irrigate the entire plot?

2. If so, how would I spread the water over this large area? i.e. hoses? pvc? etc?

3. What kind of pumping system would be best for getting water out of a pond. A consideration is that anything of value (like a pump) would be nicked quickly.

[Lickey]

Nepal, 1 rai water, 39rai land, do you plan to irrigate all this land? will it all be rubber trees? do you live on/close to the land? do you have electricity there? do you have a Kubuta walking tractor? is all the land flat or some hillside, Sorry for all these questions, but let us know and we can help you more, Regards, lickey.

[slapout]

Nepal; Just to give you a pump comparison figure, I use a 3 inch pump with 5 hp gasoline drive, outlet 3 inch swedged down to 1 inch with sprinkler every 9 meters, this will water (at one time) a line of trees about 300 meter long. You say land is flat so you have other options for irrigration than sprinklers. It takes one day (12 hrs) to cover 11+ rai of trees on 9 meter spacing with the system I use. I do pump from a well, so pump type that can be used is limited. They have very high volume pumps avaliable here if you have a tractor and want to pump into a canel or flood type system. Like Lickey mentioned, there are many questions to be answered before anyone would want to make suggestions.

[chownah]

Does the land slope down as you go away from the pond?....in other words if you pumped water out of the pond and dumped it on the ground would it flow out to all of the land you want to irrigate? If you have a never ending supply of water you can dig a series of ditches and simply pump water out of the pond using a two wheeled tractor and tube pump and just dump it into your ditch system. This type of ditch irrigation is the most wasteful of water but if there is a good supply and you will never run out and the land slopes the right way then this is probably the cheapest system as far as how much capital must be invested. Assuming that you already have the two wheeled tractor, you can buy a tube pump for about 3,000 baht (maybe less if you only need a short one) and that's about it except for the labor to dig the ditch system. The cost for fuel should not be prohibitive even though this method of irrigation requires pumping the most water since these tube pumps are very efficient. I can take one rai of VERY DRY rice paddy in the dry season and fill it to over 5 cm deep for about 100 baht for fuel as a ball park estimate.....this is way more water than would be needed to irrigate one rai of trees since you would only need to inundate the area around the tree and not the entire plot. How many rai of trees you could irrigate with this much water would depend on your skill in making your ditch system.

This kind of pump is portable so it can be locked in every nite. Do remember that a ditch system needs to have a high volume pump to operate efficiently....if you try to fill a ditch system with a small pump by pumping for a longer period you will get alot of water soaking into the ground before it can get distributed out where you want it resulting in over watering (and a resulting waste of water the moves down into the earth beyond the reach of the trees roots) in the plots near the pump and underwatering or no water reaching the distant plots.....for ditch irrigation you want a a high volume pump and design your ditches with some slope (especially in the main supply ditches) to get the water out there quickly before it all soaks in at one place....this is especially important if you have sandy soil....in very sandy soils you could use large diametre pipe (irrigation pipe) to distribute the water out to the plots which can then be themselves ditch irrigated but this can be costly and also can take more labor since you will probably need to move the pipe from plot to plot and also store it at night so it won't get stolen I guess.

chownah

[Nepal4me]

Hi Lickey, Thanks for your response. This land is very very flat. I don't live on it, nor does my wife's family. It is about 3 KM from my wife's family's home.

We plan to grow RT's on the whole plot and for the first 4 years, grow mansapalang (spelling?) between the RT's.

Kampaengphet has a fairly long rainy season but since there is a pond there on our land, I'm interested in trying to irrigate during the dry season.

There is no electricity nearby so I guess a gas powered pump would be in order.

We don't have a Kubuta walking tractor and I'm afraid I don't know what that is. Is is one of those tractors that uses it's motor to drive the pumping system?

If you could help me understand what needs to be done to irrigate this land, I'd appreciate it. Also any other questions, feel free to ask me.

Thanks again....

[Nepal4me]

Thanks Chowna and Slapout,

It is looking like I will need to get a tractor and a pump with a fair amount of volume capability. I would say there is no slope away from the pond, it is very flat. The sense I get is a ditch system with nothing to keep the water from saturating into the ground will not work as you would think the water would not last over 300 meters. So I guess I should have some kind of tubed irrigation system to get the water out to the distant trees. I wonder if this would be PVC or hose of some kind? Would PVC or hoses be stolen at night given that nobody will be living on the land?

[chownah]

Nepal4me,

Was this land previously rice paddy? If so then it was built for water to flow thorugh the different plots (plots will be demarked by earth berms) in a certain order with each plot being either the same elevation as the previous one or slightly lower. If this is the case you may be able to determine this water path across the land yourself and if you can not determine it then ask a rice farmer to come and take a look and tell you how the water would flow across your land....you could also ask the farmer if it would be possible to make a ditch system to irrigate from your pond.

Seems like I have read in some other thread that some people put a big water tank on a pick up truck and then go water rubber trees from the tank using a hose and small pump. This would be fairly cheap to set up if you had the pickup already and would not require alot of fuel as water could be delivered very efficiently to the trees so the volume of water pumped would be very small especially compared to the ditch system.

chownah

[thaipete]

I use a big old Lister marine diesel and water 50 rai, but not all at one time, when I had fruit farms they needed a lot more, but my rubber I tend to water about 10 rai for half an hour then move on, I also have access to a public reservoir, previously I had my own

[Lickey]

Nepal, thanks for information, thats given us all a better idea of your predicament, some things to consider, putting plastic PVC pipes all over limits access for tractors ect, also open to abuse by labour with weed whackers {strimmers} and perhaps even getting nicked?? A drip system of watering is also open to the same abuse, [as i found out with our first crops of the new banana and papaya,the hand powered collection trolleys obliterated it } so as you or the family are not close/on the farm, Chownahs suggestion [bless him, he beat me to it!! ] of a pick-up with a tank and a gas pump is the way to go, this happens a lot round my area, perhaps find a battered old pick-up or use your own, whatever, measure the width and allow half a meter either side as spacings for RT rows, get a Honda gas pump fill your tank from the pond, splice the outlet so you can do 2 rows at a time, and if need be, you could fit spraying nozzels for weed killer ect, Im sure others will elaborate on this a bit more for you, Cheers and good luck, Lickey.

[Nepal4me]

Nepal, thanks for information, thats given us all a better idea of your predicament, some things to consider, putting plastic PVC pipes all over limits access for tractors ect, also open to abuse by labour with weed whackers {strimmers} and perhaps even getting nicked?? A drip system of watering is also open to the same abuse, [as i found out with our first crops of the new banana and papaya,the hand powered collection trolleys obliterated it } so as you or the family are not close/on the farm, Chownahs suggestion [bless him, he beat me to it!! ] of a pick-up with a tank and a gas pump is the way to go, this happens a lot round my area, perhaps find a battered old pick-up or use your own, whatever, measure the width and allow half a meter either side as spacings for RT rows, get a Honda gas pump fill your tank from the pond, splice the outlet so you can do 2 rows at a time, and if need be, you could fit spraying nozzels for weed killer ect, Im sure others will elaborate on this a bit more for you, Cheers and good luck, Lickey.

Thanks again for your replys. I'm just back from a trip up country visiting this land. Turns out this plot of land is only 34 rai, not 40 rai not that that makes a big difference. The land was previous growing sugar cane.

So it seems a piping or hose system over the 33 rai will not be feasible. For sure it will be nicked as the land is off the main road and is 3 KM or so from my wife's family.

The water supply is unlimited. I just say this based on the fact their is a one rai sized pond there all year long.

One idea is to use a pickup with a big tank on it and drive between the RT's and pour water from the truck to the trees directly.

I wonder based on Chownah's earlier comment if I could construct a dirt moat system where I pump water out of the pond and simply irrigate the full 33 rai. As wasteful of water that would be, the excess would simply flow back into the pond I guess. The land is flat and not really sloping away from the pond so I would think (and I'm guessing and please correct me) that even with a high amount of water flowing out of the pond, I don't think it would reach the distant trees maybe 300 meters away. Please advise if simply driving water into a dirt moat system could make it out that far.

Another thought about using the truck to drive between the rows of RT's. That would be fine in years 5 and onward but in the first years, the plan would be to grow mansapalang between the RT's. So a truck would then damage the mansapalang. That option may not work.

[Lickey]

Going to admit that i dont know what a mansapalang plant is, nor does google, and the mrs is asleep, obviously you dont intend to plant it in the same rows as the trees, so the only option seems the water trenches, I would think these must be in place before any planting is done, to ensure the new roots are not disturbed, once the trenches are in place, you can buy like a firemans hose, collapsible 2inch plastic/nylon pipe, it reels up flat and easy to move around, our neighbour uses this to irrigate her 3 rai bananas, honda 3hp pump and pond, this method would ensure water getting to the far reaches i suppose, once the ditches are tottally wet, they will hold water better, same as your pond, , Good luck, Lickey.

[Lickey]

Mrs just woke up, mansapalang is the Thai potatoe, specially for animal feed, sorry about that, she always calls them potatoes too,

[Nepal4me]

Going to admit that i dont know what a mansapalang plant is, nor does google, and the mrs is asleep, obviously you dont intend to plant it in the same rows as the trees, so the only option seems the water trenches, I would think these must be in place before any planting is done, to ensure the new roots are not disturbed, once the trenches are in place, you can buy like a firemans hose, collapsible 2inch plastic/nylon pipe, it reels up flat and easy to move around, our neighbour uses this to irrigate her 3 rai bananas, honda 3hp pump and pond, this method would ensure water getting to the far reaches i suppose, once the ditches are tottally wet, they will hold water better, same as your pond, , Good luck, Lickey.

Mrs just woke up, mansapalang is the Thai potatoe, specially for animal feed, sorry about that, she always calls them potatoes too,

Hi Lickey, my wife was always calling it potatoe too and it took a long time for me to figure out that manfalang was potatoe and this was something else. Seems that's where the money (as least the short term money) is right now. Nobody's growing sugar cane anymore, everybody's growing this mansapalang stuff.

Back to the fireman's hose thing. How many meters would you need? If the distance is about 300 meters to the end of the property, would I get maybe 200 meters of fireman's hose (or would that be way way too unweildly?) and then just let the water force it's way the final 100M thru the trench we build to the last tree?

Wonder how long much time would take to do the full 33 rai?

[chownah]

Was the pond used to irrigate the sugarcane?...if so how?

Mansampalang is called cassava or tapioca....it is not related to a real potato as far as I know but its enlarged roots (I think that technically it is not a tubor but an enlarged root....but not sure) can be boiled and eaten like a potatoe...not quite as good as a potatoe but if picked at the right time and boiled properly they are good but mostly they are used for animal feed. From what I have read they are usually planted at the beginning of the wet season so they need no irrigation and by the end of the wet season they have made enough growth that they can weather the dry season without dying.....they are famous for being drought resistant which is one reason they are grown. Also, from what I've read the harvesting is very labor intensive but the yields can be impressive. I've grown a few at my place but they have always been so difficult to harvest that I've sort of given up on them...I guess you need very very sandy soil for them but again I don't know for sure. It is not commonly grown around the north except I have heard that it is grown in the mountains in places where there is no irrigation available.

Just because the pond has always had water in it doesn't mean that it can't be emptied...it might mean that it has never been pumped....in the dry season it might not be being recharged and once it is pumped it will stay dry until the rains come. It depends on where the water table is during the dry season.....

If your soil is relatively impervious (not porous) then a very flat trench can convey water long distances...however if you are going to plant mansampalang there it is probably very sandy which means you would need some slope so the water moved quickly. With all do respect I'm not really confident from what you've said that the land is flat. If you saw the irrigation ditch that I constructed you very well might think that it is flat but it drops about one metre in 200 metres and that's enough for the water to flow fast enough for my soil conditions (which very well might be better than yours...mine is a sandy clay....yours might be a clayey sand). I suggest asking some local farmer to come and look at the land and determine how it slopes or if it is really as flat as you say. My experience is that mostly the only flat land is rice land and everything else has some slope to it but you might be right and it might be perfectly flat.

Chownah