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Low-Cost Farm Irrigation

How much water does it take to cover 1 inch of an acre? 27,154 gallons.

Diaphram or Centrifugal Pump






Let's say you have a 30 acre farm. That would be approximately 350 meters by 350 meters.

If your borehole is located on one end of the farm, it means you may need to move water for up to 350 meters to irrigate crops on the other end.

The easiest solution for irrigation is to pump the water from the borehole into an overhead tank. The tank then creates pressure for a gravity fed irrigation system. An overhead tank like this could cost a lot if it has to move water as far as 350 meters.

So to reduce cost, we need to come up with an inexpensive way to move water from the borehole around the farm.

A Diaphragm Pump looks like a good idea:

Watch this video...




For proper sprinkler function, pump must be at least 60Psi, 20LPM (5.5GPM). That'll give enough pressure, and also water volume for the irrigation. Both attributes are essential.

The diaphragm pump shown is available with such features at a reasonable price.
Weight: 8.2 lbs (3.72 kg)
Price: $109
Dimensions: 8.25" X 5.30" X 6.0"


Inlet pipe:

1/2 inch pipe, 8 ft to the water source.
If the pump is far from water source, then increase the pipe size, e.g.
3/4 inch pipe, 20 ft to the water source.

Outlet pipe:

1/2 inch pipe, 100ft (30m) to the farm.
The Sprinkler irrigates the entire garden - 40ft x 35ft.
In general, if the outlet pressure is low, try different pipe sizes.

Runs on 100W.

A 12V battery can run this pump, and last for 4 days on a single charge.

A 12V 20Ah LiFePO4 = 240Wh = $50.
A bigger battery like 40Ah is probably better.


Submersible pump:

The pump in the Afon borehole is 3m3/h, 120m head.

1 m3/h = 4.40 gal/min
2 m3/h = 8.81 gal/min
3 m3/h = 13.21 gal/min
4 m3/h = 17.61 gal/min
5 m3/h = 22.01 gal/min

This can also be a pump we can use for irrigation.

Check the pressure.
The power requirement is a lot higher though.
For serious irrigation, a powerful pump is required.

Warning about Seaflo pump:
Note: Pump motor is not waterproof and should not be exposed to external water contact.
Pump must also be mounted horizontally on a level surface. Do not tilt.


Ram Pump

Wherever you have water drop, a ram pump can pump water at a 1:7 ratio. So if you have 1ft water drop, you get 7ft water lift.


MP Pumps (DC, AC) Centrifugal Pump

Centrifugal pumps increase the output pressure.

These pumps move more water. When a larger volume of water is needed, e.g. when big sprinklers are used, then these pumps are preferable. Really great for commercial agricultural irrigation.
They also run at 12V/24V. The PSI is lower though.

Caution: Do not start/stop the pump too often. If you start the motor too many times, a buildup of heat can cause damage to the motor. Every time the motor starts, the inrush current of up to 10 times the nameplate amps dissipates energy as heat.

(1)
MP Pumps FMX 75 Centrifugal Pump

Flow-Rate: 21 GPM
FLOW Up to 46 GPM
HEAD Up to 125 ft

Type: 12V DC or 24V
54 psi
Weight: 12.00 LBS
$385.90

(2)
MP Pumps FMX 75 SP Centrifugal Pump (self-priming)

Flow-Rate: 21 GPM
Type: 120V AC
Weight: 32.00 LBS
$1,311.20

(3)
MP Pumps CFX 75 12V, 24V DC Centrifugal Pump

Flow Rate: 28 GPM
Weight: 9.50 LBS
Max Working Pressure: 13.8 PSI
Head Feet Up to 38'
$307.50

(4)
MP Pumps CFX 75 115V AC

Flow Rate: 28 GPM
Weight: 25.00 LBS
$1,251.50


Double Diaphragm pump



When you need more pressure and water flow, this could be a pump to get, at a reasonable price.

Air-operated double diaphragm pump. Needs compressed air to work.
There is a 1-1 ratio between input air and output water. As you increase airflow, the water output also increases.

Perfect for use with water. Not suitable for acid, alkali and other corrosive liquids.

12 gpm 115 psi
Max Flow Rate: 2 m3/h (12 gpm)
Max Head: 69 m (226.4 ft)
Package Size: 30 x 28 x 20 cm (11.81 x 11.02 x 7.87 inch)
Gross Weight: 6.5 kg (14.33 lbs)
Price: US $111, FREE Standard Shipping.

Note: You need air compressor to run this pump.


When you're ready to go big time, and do some serious irrigation, here are bigger double diaphragm pumps

Max Flow Rate: 18 m3/h (72 GPM)
Max PSI: 120 psi
Max Head: 84 m (275.59 ft)
Max PSI: 120 psi
Average Air Consumption: 38 CFM
Package Size: 42 x 36 x 23 cm (16.54 x 14.17 x 9.06 inch)
Gross Weight: 11.59 kg (25.55 lbs)
Price: US $229, FREE Standard Shipping.


Air Compressor

As stated above, double diaphragm pumps need air compressor



Air compressors are powered by gasoline, or can be DC/AC. That means they can be solar powered too.

I do not yet know about air compressors. What compressor would run a double diaghragm pump?
People are saying a lot of air is needed, and a small DC compressor won't cut it.

Will this do...
150 psi 60L 12V Air Compressor
Price: US $67.98
Current:22A
Air flow:60L/min
Air Pressure:150 Psi
Max.Duty Cycle(@23 C & 100PSI):33%
Fiow rate@OPSI(13.8 Volts):2.54CFM
Max.Amperage:30Amp
Voltage:DC 12V
Continuity Working Period:15mins /40 psi /24?
Working Temp:-55? to 60 ?
Size(L*W*H):24.5x9x14.5cm/9.65x3.54x5.71"

Names of quality pumps that keep coming up in my searches:
ARO
Sandpiper
Ingersoll Rand


Tractor pump attachments
Hand-held tractor
Full-size tractor




Types of pumps

https://www.grainger.com/category/pumps?op=search

https://www.farmprogress.com/equipment/how-select-right-sprayer-pump

PTO Pumps


Characteristics of typical diaphragm pump:

Sprinkler Heads




3,000 gph (50 gpm).
shoots 84ft one way. 84ft the opposite way. Radius = 168ft (51 meters).
Available at: https://www.bigsprinkler.com/.



1/2 inch 3/4 inch Integrated Sprinkler
360 Degrees Rotating
Flow Rate: 0.45-1.03m3/h = 4gpm
Working pressure: 1.5~5 bar
Coverage Area: 5800 sq. ft. (538 sq m)
Spray Radius: 25m

US $18, free shipping



RAIN BIRD P5-R Impact Sprinkler
Great reviews
41ft = 12m spray Distance
Equal distribution of water all along the way
$6.99. Buy 10, get free shipping

From reviews, RAIN BIRD makes the best sprinklers.


Depending on the pump flow rate, sprinkler heads can be daisy chained to cover a larger radius at once. The water pressure would be the same for all the sprinklers in the chain, but water flow would be spread out.


DALYA IRRIGATION YUZUAK Atom 22 1" Full/Part Circle Long Throw Jet Sprinkler
Covers up to 36m radius (long range, but can it last long?)
pressure 29psi - 58psi (2 - 4 bar)
Price: $116.00




Atom 35 Impact Sprinkler Head
Flow Range: 40-143 gal per min.
Coverage: Up to 230’ Diameter
Runs on pressure as low as 29 psi
$150.00




Atom 28 Impact Sprinkler Head
is ranked among the best. #2 out of top 10




Rain bird 35ADJTNTB
is the best. #1 out of top 10
$45
42 Ft. - 51 Ft.

In the field of large-volume sprinklers, Nelson Big Gun® Sprinklers are recognized the world over as the leader in quality and performance.


Plastic vs Metal sprinklers

Plastic doesn't oxidize like the brass units. It stays free and turns as it should.


Hoses

150ft (46m) PVC Braided Hose - 1/2 Inch
₦ 20,000 (jumia)

200ft (61m) Expandable Magic Spraying Hose
₦ 14,499


Good read. 
Water reservoir







PTO Pump



PTO Tractor Pump
352 GPM
Tractor HP required is a range of 15HP to 125HP
$889
Irrigation with Seaflo 12V 5.5gpm, and RAIN BIRD P5-R