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Agronomist notebook: Cheaper ways to pump irrigation water

Saturday November 2 2019

In this past photo, Kisumu farmer Oliver Bill sets up a solar-powered water pump in his farm.

In this past photo, Kisumu farmer Oliver Bill sets up a solar-powered water pump in his farm. Solar pumps are economical because they can directly use a technology known as PV array to pump water into the tanks, which is then distributed to the farm by gravity. FILE PHOTO | NATION MEDIA GROUP 

ANN MACHARIA
By ANN MACHARIA
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To farm profitably, one needs a reliable and affordable water supply for irrigation. This is because water plays a crucial role in determining whether one will harvest losses or profits.

The water must be able to reach the crops in a cost-effective and sustainable way for one to make a profit.

Most farmers use electric, petrol or diesel-powered pumps to move water from sources such as rivers and boreholes into a tank or onto the farm directly.

Most of the time, the cost of pumping water goes up due to the fluctuating price of electricity and petrol or diesel.

The other day, I met a farmer who was unhappy because he was using a lot of money to pump water using his electric machine.

Well, there are cheaper options of pumping water for irrigation, which include solar and windmills.

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In my line of work, I have encountered several farmers who have embraced solar pumps to pump irrigation water.

Solar pumps are economical because they can directly use a technology known as PV array (without a battery) to pump water into the tanks, which is then distributed to the farm by gravity.

The solar system operates on the principle of photovoltaic (PV) technology, which converts sunlight to electricity for the machine to pump water. The cost of setting up a solar system depends on the size of the gadget.

For instance, a 120-watt solar panel, inclusive of the water pump, goes for Sh45,000. This can pump 10,000 litres of water at five metres depth and 3,500 litres at 10 metres depth, which is adequate to irrigate half an acre.

Installation of electricity definitely costs higher depending on the distance from the transformer. The cost of pumping one cubic litre of water using electricity is approximately Sh17, with the bill paid monthly.

REDUCES THE TOUGH TASK

A solar pump thus offers the farmer long-term relief as one does not incur monthly bills.

In Makueni, I recently met a farmer who uses a submersible solar pump, which he had installed below the dam, which collects water after raining.

The pump pushes the water to a maximum height of 20 metres. Surface pumps are placed above the ground and are primarily used to move water through the pipelines.

Besides being low maintenance, solar water pumps are eco-friendly as they do not release any gases into the atmosphere.

There are smaller solar water pumps for the small-scale farmer in the market, thus farmers have no excuse not to irrigate their farms affordably.

Having a water pump reduces the tough task of carrying water physically from the source to irrigate your crops.

Some innovative farmers are currently using motorbikes to pump water for irrigation or even spray chemicals, making work much easier. In this case, the farmer requires to buy a special pipe connected to the bike engine.

The machine pumps about 40,000 litres of water using a litre of petrol, which is sufficient to irrigate two acres depending on the crop and the soil conditions.

The amount of fuel to be consumed also depends on the source of water as pumping water from a well needs more fuel than from a dam.

Lastly, smallholder farmers can also use a manual flexi water pump, which is hand or leg-driven and pumps 1,600 litres per hour.