Bubbler Irrigation, Has Anyone Tried It?

[SnareBear]

Quoted from http://www.fao.org/docrep/w3094e/w3094e05.htm

"Bubbler irrigation is a partial-area, low-volume, high-frequency irrigation method based on closed-conduit delivery. It is designed to reduce investment and energy requirements by using inexpensive, thin-walled, corrugated plastic pipe of sufficient diameter that even the limited pressure available from a low-head surface reservoir might suffice. Bubbler irrigation is essentially a modification of drip irrigation, intended to make the system less dependent on industrially produced components"

See attached picture for an illustration. Around each tree is dug a shallow basin roughly the width of the tree's drip line. You lay a main pipe, 4" in the ground, then branch off to each individual tree with a 1/2" pipe, and let the pipes come up vertically inside the basin forming the "bubbler". No sprinkler, just a plain piece of PVC tube. You adjust the height of the individual tubes until they all feed water at the same rate.

My orchard is on a slope, so I was thinking of building a reservoir (1m diameter concrete pipes) at the highest point and then lay the PVC pipes in the ground accordingly. Then feed the reservoir from the local klong in the dry season, with a backup of a well with a pump when the klong dries up.

Of course this very dependant on soil quality, so the basin drains quick enough but not too quick, to wet the roots. A Thai friend said it was a bad idea because it would rot the tree but I cant see why if the soil drains quickly enough. This is basically what you do when you grow a plant in a pot.

Has anyone tried bubbler irrigation?

[slapout]

We used what you are proposing on lamyai/mango trees for the first 5 or 6 years after planting. The amount of water to those closer to the water source comes at a higher volume, than at the end of the line, thus caps were put on the pipes when the tree got the volume desired.

when a large volume pump is used as a source it can be a Chinese fire drill, putting caps on, moving same, etc. We finally put sprinkler heads in and they are still in use today. They cover drip line on 12 + year trees.

I used 3 inch feeder line from pump and came off that with valve on 1 inch pipe. I could water about 30 trees at a time, with 3 inch pump powered by 5 hp gasoline engine. The system covers about 12 rai total land with 250 plus fruit trees. Hope this helps.

[SnareBear]

Thanks slapout,<div><br></div><div>I like the simplicity of it, so I will try this to see how it works out. Some species of tree doesn't like to be flooded, but then I'll just make the basin shallower.</div><div><br></div><div><br></div>

[drtreelove]

Slapouts experience is valuable and advise sound. I don't have direct experience with the system mentioned, but I have some general comments to address your concerns about orchard irrigation.

Whatever system you use, try to irrigate as much of the soil surface as possible, within and beyond the dripline. Systems that spot irrigate do not encourage a broad ranging root zone and extensive absorbing roots that are important in water and nutrient absorption throughout the available soil profile. "Flood" irrigation, deep and infrequent is best for trees. I say beyond the dripline, because in spite of the dripline often being the perceived as extent of lateral root growth, if you provide irrigation beyond that point, the roots can extend to twice the radius of the dripline or more, depending on species and other conditions. And the more absorbing roots in the widest area possible, the more availability to the tree for water and nutrient absorption. Water as deep and as wide as possible.

Sloping terrain is a challenge and difficult to flood irrigate and get enough depth of penetration before run off. In this situation you may have to do intermittant irrigation by monitoring for the point of runoff, then stopping to allow penetration, then starting and stopping again until your soil sampling tube, moisture meter, or shovel test hole shows enough depth of water penetration. Go for at least 6 inches, better for 10 to 12 (25 to 30 cm). "Know thy soil" and how fast it drains and how much water it takes to get the depth of soil moisture you want. Sample in between cycles to fine tune your irrigation program. Green manure or mulch to continually improve soil organic matter content and your soil will retain moisture longer, as well as improve fertility and structure.

Your friend's concern about creating conditions for root rot are legit, but only a factor if drainage is poor or you irrigate too frequently of if you have basins that hold water at the root collar for extended periods of time. If you flood irrigate infrequently, like every week or 10 days during the dry season, and allow time for the root collar to dry out in between watering, then you should have no problem with root or root crown rot. Don't pile soil or mulch up on the basal tree trunk and don't trap water in basins at the base during rainy season. don

[rice555]

Hello Snare Bear, I've used these:

http://www.netafim.com/product-category/pc-micro-sprinklers-emitters

but only a 100M run, they work very good on flat land, how ever they have

a built in metering system(PC) so the all discharge the same in relation to

elevation. Work with 1.5-4 Bars of pressure.

IF they do clog up, the metering part removes from sprinkler body with 1/4

turn.

To get an idea what they can be used on, go to each model, then to the

download link on the R/H side. At the top of the pdf., their is a picture of

their use.

I used 50M of 25mmLDPE and the last 50M of 20mmLDPE from a 1" pump.

My Spinnet's have the 1/4" poly feeder tube.

The 1/2" threaded attach fitting would work good for bared PVC.

Naan Dan/Jrain have simular PC sprinklers to Netafim.

Netafim BKK has some models, but for 'specific' setups, they would have to

be ordered, takes about 1month.

rice555

[SnareBear]

drtreelove, rice555,

Great advice, thanks for taking the time to reply.

On the subject of trees, I have too much unused land and I want to plant some long term low maintenance trees. Not for commercial purposes, just for my own supply of wood etc. Any suggestions?

I was thinking of:

Mai Sak (Teak) - for the wood

SaDao (Neem) - for the wood and the edible flowers.

Pai Liang - to use for construction

Pai Trong - construction and edible shoots

Yang Pala (Rubber tree) - not sure if the trees produce rubber up here in the North, but I could use the wood for handicraft.

Eucalyptus - for the wood

Edited July 19, 2010 by SnareBear

[drtreelove]

I would suggest that you mix it up and plant selected species for your various purposes. If it's not for commercial purposes then you don't need to mono-crop. Also you don't have to plant all at once. You can pick and choose and plant as you discover other species and uses. Mix with legume trees, and as you may know, some trees create mulch for themselves and nearby trees with heavy leaf litter. Just address the compatibility issues with spacing and cultural requirements, irrigation or not, and drainage, etc. Plan for how and when you are going to maintain and harvest, access for tractor, truck, etc. There is an old thread on 'agroforestry' with lots of great input from growers with more experience in this area than I, and that thread may be pinned. don

I don't think this is the thread I was thinking of, but it has some interesting and useful posts. From the organic subforum: http://www.thaivisa.com/forum/topic/252460-agricultural-permaculture-forest-gardening/

Edited July 19, 2010 by drtreelove