By Antynet Ford

Chilli farmer Beatrice Mwende from Murang’a county has slashed her irrigation costs by nearly 90 per cent after replacing petrol with cooking gas to power her water pump. 

Irrigation costs can be an important calculation for farmers. Reducing upfront pump costs can help them begin irrigation, but many cheaper systems to buy and set up are then far more expensive to run each season.

“Before I was using petroleum to pump the irrigation water but I realised that it was not cost effective. It was becoming very expensive because I was spending Sh2,800 to irrigate one acre with 15 litres of petroleum. Irrigating with a gas cooker I use Sh950 to refill the 6kg gas and I use it to irrigate one acre twice a week. The maximum I have used to refill the gas is Sh1,100,” said Beatrice.

Her choice of crop makes reliable irrigation crucial. Chillies need about 600–1,200mm of water in a growing season, or 20–30mm a week during flowering and fruiting. They are very sensitive to the wrong amount of water. Too little causes stunted plants, flower drop, and small fruits, while too much leads to root rot, fungal diseases, and lower pungency.

In high rainfall areas such as the Central Highlands and Western Kenya there can be too much rain for chillies. Areas like Laikipia, Meru, and Nakuru can be ideal, but it matters how regular the rainfall is, while counties like Kitui and Makueni need irrigation to grow chillies.

Another alternative for farmers to irrigate is solar pumps. 

Diesel pumps are often cheaper to buy, costing from Sh17,000 to Sh225,000 depending on size, but have high running costs due to fuel. Solar pumps cost between Sh19,000 and Sh180,000 depending on model and kit size, but have no fuel costs. Including the initial cost of a pump, irrigating one acre for a season costs about Sh68,800 with a mid-range diesel pump versus Sh27,500 with a solar pump kit, a difference of Sh41,300 in favour of solar.

Different irrigation systems also use different amounts of water.

Basin irrigation is one of the oldest watering methods, where a plot is surrounded by small soil bunds to hold water in a shallow pool. It is cheap to set up but often wastes water and can damage crops that dislike waterlogging.

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“I am currently using basin irrigation because it is cost friendly. But in a year’s time, I intend to use drip irrigation because it is the recommended irrigation for chilli,” said Beatrice.

“Installation of drip irrigation is very expensive but I hope to have made a good saving next year such a time. When I begun the farming of chilli, I didn’t have the capacity to make the installation. The disadvantage of basin irrigation is that water gets everywhere unlike drip where water goes directly to the plant hence there is minimal wastage of water,” she said.