Uganda’s soils present a paradox: fertile-looking, deeply red laterite soils that in practice yield poorly due to low pH, high aluminium toxicity, and limited water retention. GBG’s applied research programme has been running field trials since 2023 to quantify how biochar addresses these constraints.
Trial Results
Across 12 trial sites in Central and Eastern Uganda, biochar application at 2.5–5 tonnes per hectare delivered consistent yield improvements of 15–30% for maize and 18–25% for beans, compared to control plots receiving conventional fertiliser only.
Soil pH improved from an average of 4.8 to 5.6 within two growing seasons — a significant shift that reduces aluminium toxicity and improves nutrient availability. Water-holding capacity increased by an average of 22%, reducing crop stress during dry spells.
Why Biochar Works in Tropical Soils
The porous structure of biochar provides habitat for soil microbes and creates ion exchange sites that hold nutrients in the root zone. In tropical soils that are frequently leached by heavy rainfall, this nutrient retention effect is especially valuable.
GBG produces biochar from eucalyptus at temperatures between 450–550°C, which produces a product with high surface area and stable carbon content exceeding 70% — meeting EBC certification requirements for agricultural use.