From rice husk waste to fertiliser

Samuel Wahome, a vegetable farmer, demonstrates how to apply fertiliser to vegetables at his farm in Mwea. Wahome is one of the farmers who uses the organic fertiliser to top dress his spinach and Sukuma Wiki. (PHOTO: ALLAN MUNGAI/ STANDARD)

Thanks to the innovation of a 28-year-old man in Mwea, rice farmers are able to transform waste generated by rice production into affordable, organic fertiliser.

Every day, 15 tonnes of rice husks are produced by rice farmers in Mwea, Kirinyaga County. These husks are either dumped or burned, which affects the environment.

Now, 28-year-old Samuel Rigu has come up with an environmentally friendly solution to deal with this eye sore. He is converting the rice husks into organic fertiliser.

To do this, the graduate of Agribusiness Management from the University of Nairobi first established Safi Organics in Mwea town.

He says he was driven by the desire to reverse the trend of diminishing returns farmers were contending with primarily due to degrading soils.

“Unknown to most farmers, the chemical fertilisers they use end up increasing soil acidity which reduces the productivity of their farms,” Rigu says.

But through his product, Safi Sarvi, the 2016 Total Startupper of the Year winner, promises a solution:

“This is a carbon negative organic fertiliser. It will amend the soil and promises up to 30 per cent increased yields from the farm,” he says.

Rigu says they first procure rice husks from millers and convert it into black carbon negative biochaff in a process that takes between two and three hours. From there, the biochaff is left to inoculate in a heap for three days to allow regrowth of microorganism.

After this, it is mixed with organic components developed by the Massachusetts Institute of Technology and is then passed through a machine that mixes and breaks it down into smaller components. It is these that are packed, weighed and sealed in 50 kilogram bags ready for the market.

To confirm the assertion made about his product, Rigu says they first had to conduct trials, test soils and provide extension services.

“From the positive reviews that we got from farmers that we bench marked with, many others have gained confidence to venture fully into organic fertiliser,” he said.

According to research on the product done by the company, Safi Sarvi is a macro nutrient fertiliser that contains 10 per cent Nitrogen, Phosphorous and Potassium while 55 per cent comprises organic matter.

Rigu says unlike chemical fertilisers whose nutrients are quickly washed up (leached) leaving the plant bare, the organic fertiliser - while soluble, provides a counter action because it is slow releasing.

A bag of this fertiliser goes for Sh1,500 as compared to other inorganic fertilizers that go for about Sh3,200.