Drip Irrigation

[mdsharief]

Hello Friends,

I farming lemon plants in Northen Thailand (Uttaradit) Hilly slope area around 20 rai. Can anybody assist me to design plan for Drip Irrigation system for uneven slope hill area. Immediate response highly appreciated.

Sharief

[slapout]

The shape of your 20 rai, gradient of slope on the plot of land, source of water in relation to land, distance between plant/trees rows, this info would help to make a plan.

[mdsharief]

The shape of your 20 rai, gradient of slope on the plot of land, source of water in relation to land, distance between plant/trees rows, this info would help to make a plan.

Drip Irrigation for 2500 Lemon Tree Plantation.

Distance between Trees is 3 meter x 5 meter

i have slope area of 6 acre in 45 degree angle. Uneven Surface. From Hill top to bottom its 150 meters.

I have a Water Well at ground level from which i need to pump up of water.

What capacity pump/motor to use, and pipes how much and what is the pattern of laying pipes, mico sprinkers, .......etc.

Hope the attached picture gives you rough idea.

I can send u more pictures if you could give your mail id.

email removed, please PM

[slapout]

I think your first concern is to get a water storage system at the upper level of your property, which means pumping from your well (as marked) up a gradient 150+_ meter, which is 106+_meter higher in elevation than the well. The water storage would probably work best if placed in the middle of the horizontal measurement of the land (360 +_meter) This is based on photo 1 only and the possible use of soaker lines.

If soaker hose is to be used, they can be connected via a cut off valve to a water source line , which would run the horizontal 360 meter and be connected to the water storage facilities. This is just a quick look idea and others may have much better idea/suggestions. A lot depends on how labor intensive you want and how much you want to invest.

I gather there is no electric available for water pump? How deep is well, size pipe installed and volume it will produce and level of water in well? How many months per year will irrigation be needed?

[WatersEdge]

Yes, Water Storage at the highest point of the property,

then distribution lines on level vertical increments to your trees

The downside of a large reservoir on top is greater pumping costs,

since you pay for the energy all the way to the top,

only to have that water come back down to the trees at lower elevations

requiring pressure regulators

I would suggest storage tanks placed at regular vertical increments up the side,

with float valves on each tank,

so that water pumped from the bottom requires only the energy to reach the correct elevation.

It is still generally a good idea to have a much larger reservoir at the highest elevation.

with capacity for several days operation,

as a backup plan should your pump have problems.

Irrigation design considers the worst case,

rather than waiting for an avoidable crisis to ruin a plan with no reserves.

One detail...with such an emergency reservoir arrangement,

the full pressure of the top reservoir cannot be on line during normal operation,

as it would continually require maximum pumping energy,

losing the energy advantage of vertical increment tanks.

The supply line to the top reservoir should be an open discharge over the top of the reservoir.

with an emergency operation valve to the mainline, normally closed.

Of course the lower tanks will fill first, shutting off as they are full,

then the pressure will increase to fill the next higher tank.

To state the obvious,

it will be much cheaper to irrigate the lower elevations.

If you indeed have over 100 meters of vertical difference,

you will need the heaviest grade of PVC pipe 13.5 bar

for the distance more than 85 meters below the Top Reservoir.

And 8.5 bar pipe for the distance between 50 and 85 meters below.

That is, From the pump upward, you will need the heaviest pipe.

Decreasing to the lighter grades as you reach 85 and 50 meters head.

PVC pipe is graded in bar, with three grades, 5.0, 8.5, and 13.5 bar.

A bar is 10.35 vertical meters of water head.

The initial cost of the several tanks is greater, of course,

but the savings will return daily during irrigation season.

Note that a pump which will deliver over 100 meters head is a bit specialized.

A turbine pump placed down in the well is the most efficient.

If you have electricity at the well, this is the cheapest form of pump energy.

Avoid the idea of more than one pump,

each lifting the water only part of the full elevation.

as the 15-30% efficiency loss of each pump is costly.

Design one pump for the full elevation, Well to Top Reservoir

Design the capacity of the pump for long periods of operation at low volume,

as this will reduce pipeline friction, and permit smaller mainline size.

The rule of thumb for low friction pipeline flow

is to keep the water velocity below 1.5 meter / second.

Below 1.0 meter / second is best, of course,

Pipe is expensive on the first day, but free every day thereafter.

It may pay you to consider more than one pump,

each designed for efficient operation at a different elevation range.

A pump capable of over 100 meters head is not going to be optimally efficient at lower head.

Not a big factor, just a possible refinement.

During rainy season, level retention trenches will maximize water storage in the soil,

while minimizing runoff and therefore eliminating erosion.

Force every drop of water to work in order to reach the river.

Keep it on high ground

Don't let it get away.

In the Chinese Rubber Plantations in Shan State Burma,

vast areas of countryside are completely covered with level retention pathways

which enable footpath access to the trees,

as well as capturing all rainfall where the trees need it.

Depending on the steepness of the slope, of course

The contoured pathways are on about 2 meter vertical increments

1 meter wide,

with trees spaced about 2 meters apart

Tree planting pits are about 0.60 m cubed

It is a very impressive sight,

perfect order imposed on a random mountain landscape,

as far as you can see in all directions,

with only the ridge tops remaining in native jungle vegetation

There are reasons some people don't like monoculture,

but it still is an inspiring view for a farmer.

The photos show a bottomland ravine.

It is possibly a good idea to dam this off,

creating a multipurpose fish pond / irrigation reservoir / erosion silt trap / flood reduction buffer

Just a sideline observation, not critical to the question at hand.

A useful consideration for irrigation is to save the water at the tree.

Conserve every available bit of weed & leaf matter, burning nothing ever,

but collecting it around the tree.

Grass and weeds compete for precious irrigation water as well,

but the biggest concern is soil surface evaporation.

In an orchard, you have a lot of open area between young trees,

which in the early years at least

can be intercropped.

Not only does intercropping make good use of rainy season surplus water,

it enables you to accelerate the amount of mulch vegetative matter,

to then pack around the trees.

I would recommend Perennial Peanut,

a groundcover legume which can withstand extended dry periods.

You will see it all over Thailand as an ornamental ground cover in hotel grounds, government buildings, etc.

It has the typical peanut trifoliage, the trademark small yellow flowers,

it just doesn't stand up off the surface,

and also doesn't bear nuts.

It is a good choice for a steeply sloped orchard.

It is propagated just by tearing the rhizomes out of the ground,

and putting them into the soil in the new location.

It spreads slowly to completely cover the area.

Lots of other perfectly fine choices, that's only one.

Crops with a useful product also are a good idea.

I raise Okra and regular Peanut

On this property, you have ready made good Goat grazing.

as the goats won't eat the lemon trees,

but will keep other things under control.

They thrive on steep hillsides, and love hot dry weather.

I will close as I'm going widely off topic.

[mdsharief]

I think your first concern is to get a water storage system at the upper level of your property, which means pumping from your well (as marked) up a gradient 150+_ meter, which is 106+_meter higher in elevation than the well. The water storage would probably work best if placed in the middle of the horizontal measurement of the land (360 +_meter) This is based on photo 1 only and the possible use of soaker lines.

If soaker hose is to be used, they can be connected via a cut off valve to a water source line , which would run the horizontal 360 meter and be connected to the water storage facilities. This is just a quick look idea and others may have much better idea/suggestions. A lot depends on how labor intensive you want and how much you want to invest.

I gather there is no electric available for water pump? How deep is well, size pipe installed and volume it will produce and level of water in well? How many months per year will irrigation be needed?

I am getting new Electrical connection soon for the Motor Pump. Well depth is about 10 meter. 12 months a year water is full in the well.

i have not yet installed pump & pipes but planned to buy 16000 Gallon per hour, 3 hp pump. Connect 2" pipe main line and 20mm pipe drip line pipe. and .5 GPH Micro sprinkler at each plant. This is my plan only which i have to verify with somebody who knows well about drip irrigation system.

Since i have to connect Micro sprinkler emmiters, my friends suggested me not to connect water supply from the Tank. They advise me to connect directly from the pump. These are newly planted lemon plants, irrigation will be 15 days a month (alternate) days if there is no rain.

I have designed my own irrigation plan, collecting information through internet and friends. Attached please find.

Now my Question is that correct i connect 16000 gallon per hour pump? Which micro sprinkler emmiter i have to connect at each plant (total 2500). is .5 gph ok or 1gph or more?, Is that water pressure enough to flow in all the soak pipes or i have to Irrigate Area wise.

I will be glad if anybody can assist me.

[mdsharief]

Yes, Water Storage at the highest point of the property,

then distribution lines on level vertical increments to your trees

The downside of a large reservoir on top is greater pumping costs,

since you pay for the energy all the way to the top,

only to have that water come back down to the trees at lower elevations

requiring pressure regulators

I would suggest storage tanks placed at regular vertical increments up the side,

with float valves on each tank,

so that water pumped from the bottom requires only the energy to reach the correct elevation.

It is still generally a good idea to have a much larger reservoir at the highest elevation.

with capacity for several days operation,

as a backup plan should your pump have problems.

Irrigation design considers the worst case,

rather than waiting for an avoidable crisis to ruin a plan with no reserves.

One detail...with such an emergency reservoir arrangement,

the full pressure of the top reservoir cannot be on line during normal operation,

as it would continually require maximum pumping energy,

losing the energy advantage of vertical increment tanks.

The supply line to the top reservoir should be an open discharge over the top of the reservoir.

with an emergency operation valve to the mainline, normally closed.

Of course the lower tanks will fill first, shutting off as they are full,

then the pressure will increase to fill the next higher tank.

To state the obvious,

it will be much cheaper to irrigate the lower elevations.

If you indeed have over 100 meters of vertical difference,

you will need the heaviest grade of PVC pipe 13.5 bar

for the distance more than 85 meters below the Top Reservoir.

And 8.5 bar pipe for the distance between 50 and 85 meters below.

That is, From the pump upward, you will need the heaviest pipe.

Decreasing to the lighter grades as you reach 85 and 50 meters head.

PVC pipe is graded in bar, with three grades, 5.0, 8.5, and 13.5 bar.

A bar is 10.35 vertical meters of water head.

The initial cost of the several tanks is greater, of course,

but the savings will return daily during irrigation season.

Note that a pump which will deliver over 100 meters head is a bit specialized.

A turbine pump placed down in the well is the most efficient.

If you have electricity at the well, this is the cheapest form of pump energy.

Avoid the idea of more than one pump,

each lifting the water only part of the full elevation.

as the 15-30% efficiency loss of each pump is costly.

Design one pump for the full elevation, Well to Top Reservoir

Design the capacity of the pump for long periods of operation at low volume,

as this will reduce pipeline friction, and permit smaller mainline size.

The rule of thumb for low friction pipeline flow

is to keep the water velocity below 1.5 meter / second.

Below 1.0 meter / second is best, of course,

Pipe is expensive on the first day, but free every day thereafter.

It may pay you to consider more than one pump,

each designed for efficient operation at a different elevation range.

A pump capable of over 100 meters head is not going to be optimally efficient at lower head.

Not a big factor, just a possible refinement.

During rainy season, level retention trenches will maximize water storage in the soil,

while minimizing runoff and therefore eliminating erosion.

Force every drop of water to work in order to reach the river.

Keep it on high ground

Don't let it get away.

In the Chinese Rubber Plantations in Shan State Burma,

vast areas of countryside are completely covered with level retention pathways

which enable footpath access to the trees,

as well as capturing all rainfall where the trees need it.

Depending on the steepness of the slope, of course

The contoured pathways are on about 2 meter vertical increments

1 meter wide,

with trees spaced about 2 meters apart

Tree planting pits are about 0.60 m cubed

It is a very impressive sight,

perfect order imposed on a random mountain landscape,

as far as you can see in all directions,

with only the ridge tops remaining in native jungle vegetation

There are reasons some people don't like monoculture,

but it still is an inspiring view for a farmer.

The photos show a bottomland ravine.

It is possibly a good idea to dam this off,

creating a multipurpose fish pond / irrigation reservoir / erosion silt trap / flood reduction buffer

Just a sideline observation, not critical to the question at hand.

A useful consideration for irrigation is to save the water at the tree.

Conserve every available bit of weed & leaf matter, burning nothing ever,

but collecting it around the tree.

Grass and weeds compete for precious irrigation water as well,

but the biggest concern is soil surface evaporation.

In an orchard, you have a lot of open area between young trees,

which in the early years at least

can be intercropped.

Not only does intercropping make good use of rainy season surplus water,

it enables you to accelerate the amount of mulch vegetative matter,

to then pack around the trees.

I would recommend Perennial Peanut,

a groundcover legume which can withstand extended dry periods.

You will see it all over Thailand as an ornamental ground cover in hotel grounds, government buildings, etc.

It has the typical peanut trifoliage, the trademark small yellow flowers,

it just doesn't stand up off the surface,

and also doesn't bear nuts.

It is a good choice for a steeply sloped orchard.

It is propagated just by tearing the rhizomes out of the ground,

and putting them into the soil in the new location.

It spreads slowly to completely cover the area.

Lots of other perfectly fine choices, that's only one.

Crops with a useful product also are a good idea.

I raise Okra and regular Peanut

On this property, you have ready made good Goat grazing.

as the goats won't eat the lemon trees,

but will keep other things under control.

They thrive on steep hillsides, and love hot dry weather.

I will close as I'm going widely off topic.

Hello Friend, Thank you very much for lot of new idea. Great!!!. Thank you once again.

Regarding Irrigation plan, check out below pictures and reply to Memeber Mr. Slapout

Hope u can help after seeing my design plan.

[WatersEdge]

16,000 gallon per hour is 1,008 liter / minute

3 hp will not pump that volume to a head of 100 meters

You would need something like 30 hp to achieve this.

I assume therefore that you mean to say 1,600 gph?

However let's return to the basics.

You have 2,500 trees,

each with a drip emitter of 0.5 gph.

1,250 gph => 79 liters per minute.

This is very achievable on a 3 hp pump.

It can be handled perfectly well on a 2 inch line,

which will handle a little over 200 liters per minute at low friction loss.

Imagine me saying this, you could even use a smaller line.

I suggest that you run your mainline across the bottom of the property,

rather than across the top,

so that only the necessary emitter line pressure is required.

As I proposed above, vertical increment storage tanks

with float valves

enable you to use only necessary pump energy.

I presume you intend to open all 2,500 drip emitters at once?

The cost of 1.25 meter diameter x 0.40 m high precast concrete rings,

is only B180 each, for a water capacity of 415 liters each

If a concrete foot pad is poured, with three or four rings stacked,

it will be sufficient tank capacity to operate your 50 meter drip lines

thus enabling the continual energy conservation.

This still represents a large initial expense,

it will repay in energy savings every day thereafter.

A modest pressure difference across your individual drip line regulators is fine,

but I'd predict problems if the regulators on the bottom half of the property

were continually holding back high pressure of 50 - 100 meters head.

I'd suggest not more than 10 meters head across any given regulator

What is the operating pressure for your drip emitters?

[mdsharief]

Hello Friend,

I appreciate your detailed reply. Thanks.

I am very new to agriculture and Irrigation etc. This totally new and very interesting.

I am in a process of land preparation now. By the end of this month planting will finish. Before planting Lemon trees, i have to complete installing drip irrigation. I have not yet purchased any enquipment or pump or motor.

Forget about my design. I have attached a PDF file detailing my land measurement and photo. Could you please work out a plan? Since the Lemon trees requires medium diameter water spread, we have to use, mico spinkler emitters.

1.

Each Lemon tree requires 5 to 8 litres of water every day.

I have got 2500 lemon tree in total (Area 1 - 1356, Area-2 - 1144) (Drawing of area 1 and 2 attached)

Each day aprox 2 hr. we irrigate or depends on the size of the Micro sprinkler emmitter how much it emits water per hour.

Angle of the slope is 45 degree and un even surface. Height 150 meter. width area1- 360 meter, Area 2- 150 meters.

Since irrigation for LEmon Tree, we have to use Micro sprinklers to cover larger dia. Does Water from the Tank give sufficiant pressure for mico sprinklers? So i think we need to connect direct from pump.

2. Surface of the land is as i said in 45 angle height. both the area. I have planned to plant the trees horizantally. I have mentioned in attached drawing.(new) Please advise

3. I believe i saw PE pipes in your Uttaradit shop 2" pipe 25mx 4 = 2100 Baht and 20mm pipe 200mm length=470 Baht.

4. 2500 lemon tree in total (Area 1 - 1356, Area-2 - 1144) (Drawing of area 1 and 2 attached - New)

Sorry to bother you and thanks for your valuable time.

[mdsharief]

Here is that PDF file

Land_Details.pdf

[mdsharief]

Any assistance on the above matter?

[slapout]

Probably you best bet is to hire someone to visit the land, verify water volume from well, determine real, measured lift of fluid that will be involved, size the pump/motor for the area, volume, fluid lift, etc. Then recommend water storage, the various pipe size with proper pressure rating, area under irrigation at one time, hardware to accomplish this, etc, etc. We have thrown out some guidelines/ideas for your consideration.

I would not want some to design a home for me unless he had physically walked/looked, run elevations of the site and set down to know what I wanted individually so those desires could be incorporated into the plan. In the real world their are companies who sell all of the required equipment who would do this with the hope of you purchasing equipment from them, with a firm bid and guarantee. Might be hard to find but worth checking into.

[lannarebirth]

Before you get too heavily invested you might check to see if your neighbor burns off the growth on his land each year, because if he does, he'll likey burn your land as well. I lost a few hundred meters of PVC pipe and a hundred or so trees this year from that. Good Luck.

Edited June 4, 2010 by lannarebirth

[mdsharief]

• Before you get too heavily invested you might check to see if your neighbor burns off the growth on his land each year, because if he does, he'll likey burn your land as well. I lost a few hundred meters of PVC pipe and a hundred or so trees this year from that. Good Luck.

• Thats True. Corn field, they burn every year near my land. Which i took care. Feel safe but god bless us!!!!
  

[mdsharief]

Probably you best bet is to hire someone to visit the land, verify water volume from well, determine real, measured lift of fluid that will be involved, size the pump/motor for the area, volume, fluid lift, etc. Then recommend water storage, the various pipe size with proper pressure rating, area under irrigation at one time, hardware to accomplish this, etc, etc. We have thrown out some guidelines/ideas for your consideration.

I would not want some to design a home for me unless he had physically walked/looked, run elevations of the site and set down to know what I wanted individually so those desires could be incorporated into the plan. In the real world their are companies who sell all of the required equipment who would do this with the hope of you purchasing equipment from them, with a firm bid and guarantee. Might be hard to find but worth checking into.

Yes Friend, u r right. I will work on it