National Irrigation Authority rice and maize irrigation scheme in Bura and Hola

Biochar is a charcoal-like substance that’s made by burning organic material from agricultural and forestry wastes. It is black, highly porous, lightweight, fine-grained and has a large surface area. Biochar is produced using a specific process to reduce contamination and safely store carbon. Within the irrigation scheme, farmers make biochar using rice husks. Since its composition is approximately 70 percent carbon, the farmers use it in their fields to help increase soil carbon and hence water holding capacity. 
https://irrigation.go.ke/2022/11/03/bura-irrigation-scheme-the-land-of-crop-diversity/