Farmers use wheels and mirrors to end potato blight

A contraption invented by a local agricultural economist is using mirrors to concentrate the sun onto soils to clean out pathogens and diseases and end the practice of soil roasting, which is destroying Kenyan forestry.

The solar concentrator, made with a bicycle wheel, a ball of string and a range of mirrors arranged in a semi-circle, concentrates a huge amount of  sunlight onto a container of soil. “We have managed to prove that temperatures go up to 3,000 degrees on the concentrator which are enough to kill any pathogen in the soil no matter how stubborn,” said Mr Peter Mwathi, the inventor of the solar concentrator.

The majority of the eliminated pathogens are the nematodes that cause crop wilts such as potato and banana wilt, which are some of the biggest diseases facing farmers. A 2011 survey by regional farmers' NGO Bridgenet Africa found that potato blight was among the major causes of the potato shortage in the country last year, which saw a 60 per cent increase in potato prices as farmers turned to pesticides that did nothing to improve the situation.

This was happening against the backdrop of continued logging of trees by farmers for wood to roast the soil. The traditional practice has been to lay wood across the soils and burn it, to eradicate the pathogens.
“In Nyeri, where the uptake of the concentrator is encouraging, we have seen farmers now moving away from deforestation, which was a very serious problem in the area,” said Mwathi.

Leah Nduire a coffee farmer in Karatina, has used the concentrator for the last one year, after she got a warning from the government for felling a huge number of trees to run her coffee farm. “In this area, you definitely have to roast the soil, because it is very easily degraded, difficult and expensive to regenerate. I felled every tree I could get to roast the soil until I received warnings and summons from forestry officials. So you can imagine my relief when I heard of the solar concentrator,” she said. Leah says she has also saved 50 per cent of her labour costs by using the concentrator.

The downside with the concentrator, however, has been its price, at currently Sh20,000, which is prohibitive for many farmers, even though Mr. Mwathi allows payment in installments. In Nyeri county, where the concentrator was introduced, only 15 farmers out of over 100,000 who know about the concentrator have yet bought it. “The amount is really small considering the return and savings that one gets from using the concentrator.  But since farmers have expressed so much interest in the concentrator, but are held back by funding we are exploring other tangible options to make it readily available,” said Mwathi.

Already, he has started training the youth in the area on how to make the device. The Ministry of Youth Affairs has also approached him with an interest in supporting his venture. “Since I have been doing it alone and sourcing for the materials on my own, I have been forced to charge that price, but if this  training picks up well, we will definitely lower the cost to farmers.”
Mwathi says if the training moves according to plan, the price will come down from the current Sh20000 to Sh10,000. “I know how badly the farmers need this technology and hope by yearend it will be accessible to as many farmers as possible,” he said.

Written by Bob Koigi for African Laughter

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