Samuel Rigu is coy about the secret potion he adds to his fertiliser, saying the brown liquid is called “Safi Proprietary Enhancement Formula.”
He's less shy about the results.
At his processing plant in Mwea, Kirinyaga, Rigu has found a way of turning agricultural waste into an organic fertiliser that retails at less than half the price of its inorganic alternative.
Rigu's customers and scientists say it's more effective and kinder to the soil
Globally, there is renewed interest in organic fertiliser as global prices for chemical inputs skyrocket because of the Ukraine war.
Rigu says demand has spiked since the onset of the crisis.
This, he says, has prompted him to double the size of his team, who are working 18-hour days and producing 35-45 tonnes of fertiliser per week, double the output before the conflict started.
For now, Rigu's target market is small-holder farmers who have been using synthetic fertilisers for years but have seen their yields decline over time as their land becomes degraded.
“Their soils have been slightly turning acidic and that makes them infertile,” he says.
“We are here to rejuvenate that, or reverse it.”
Rigu started the fertiliser business in 2013, when he saw mountains of rice husks being burnt, polluting the environment and contributing to greenhouse gas emissions.
First, his team sets fire to mounds of rice husks, letting them smoulder for around eight hours, employing a similar low-oxygen burn as used in charcoal production.
When the carbonised husks, known as biochar, have cooled, the team adds the mystery enhancement formula, mixing and turning the black substance until the right level of moisture is achieved.
Leigh Ann Winowiecki, a soil scientist at World Agroforestry says biochar such as Rigu's, adds nutrients to the soil and helps it retain moisture, combat erosion, encourage micro-organisms, and restore acidity levels.
Tomato farmer, David Irungu says his crops do grow well and during harvesting, his fruits are even bigger than before.
For Rigu, that translates into happy customers like Irungu.
Edited by Kiilu Damaris
