Number Of Sprinklers In 1 Acre

The number of sprinklers in 1 acre is a common question by farmers during the company’s free agronomy field training sessions.

How many sprinklers per acre in Kenya depends on the following factors

1. The type of sprinkler; impact sprinklers discharge less water than rain gun sprinklers for the same inlet size. For instance, a 1-1/2″ impact sprinkler has less water volume than a similar size of a rain gun or a lawn pop up sprinkler. So a higher number of pop up sprinklers will be required
2. The inlet size. the larger the sprinkler inlet, the higher the water volume discharged. A 3/4″ discharges more than a 1/2″ sprinkler
3. Number of sprinkler nozzles. Some sprinkler have more than one nozzle; a major one, and a minor one. The nozzels are placed opposite each other in impact sprinklers, and one on top of the other in rain gun sprinklers. These sprinklers discharge more water than a mono-nozzle sprinkler

 

4.   The pressure available. At high pressure, the sprinklers work optimally, and the spray area coverage is wide. At low pressure, more sprinklers will be added to cover for the lower coverage. The pressure is determined by the size of the pump and motor or generator engine. The larger it is, the greater the pressure

5. Volume of water available. This is either from the source, or that delivered by the water pump. With sufficient water volume, the sprinklers will cover a wide area. If insufficient, adding extra sprinklers will be unhelpful too. The volume of water available is also deermined by he size of the main, and sub main line. The larger it is, the greaer the amount of water delivered to the sprinkler

6. Budget. Considering the steep cost of having many sprinkler units in an area, most farmers opt for a portable system whereby a few units are moved around the farm until full irrigation is accomplished

 

Number of sprinklers in 1 acre

	Sprinkler inlet size in inches	Diameter of coverage (M)	Area of spray (M2)	Number of sprinklers in 1 acre
	1/2	7	11	368
	3/4	12	19	215
	1 (impact sprinkler)	18	28	143
	1 (rain gun sprinkler)	22	35	117
	1.5 ( rain gun sprinkler)	30	47	86
	1.5( flange type rain gun sprinkler)	40	63	64
	2 (rain gun sprinkler)	40	63	64
	2 (flange type rain gun sprinkler)	50	79	52

 

These sprinkler numbers are based on these assumptions;

i. The optimal pressure and volume has been achieved

ii. That is its a fixed sprinkler system ie. none is being moved from one point of the farmm to the other

Number of sprinklers in 1 acre

Steps To Install Sprinklers

1. Determine the water source and volume this must be sufficient for the target acreage
2. Determine the vertical, and horizontal distance from the water source to the point of sprinklers installation
3. Work out the requisite water pump size based on the target acreage, target crop, the vertical elevation, and the horizontal distance
4. Establish the right main pipe diameter size based on the installed water pump
5. Establish the right sub main or lateral pipe diameters based on the sprinkler inlet size diameter
6. Prepare the main pipe trenches
7. Prepare the sub main or lateral pipes trenches
8. Connect the sprinklers to the lateral pipes
9. Run the water pump
10. Check the spray volumes and diameter of spray for each unit

Number of sprinklers in 1 acre

Things to know

• The sprinkler out put is not determined by the sprinkler material. Plastic and metallic sprinklers of the same size and make will provide the same volume. However, the plastic one has a shorter lifespan
• The elevation of the land will not determine the volume of spray when the pressure is optimal
• Soil types determines how long irrigation takes. Sandy soils for instance hold less water than clay soils
• The spray diameters in a sprinkler must overlap to avoid ‘dry shadows’ in between
• Depending on the power of the pump in use, the sprinklers will be sub divided into blocks where each block or a few blocks operate at a time