Evaluating locally produced biochar effect on soil fertility and maize yields in sandy soils of Mhondoro Ngezi district of Zimbabwe.

Abstract

This study evaluated the effects of locally produced biochar on soil fertility and maize productivity in sandy soils within Mhondoro Ngezi District, Zimbabwe. The research aimed to assess how biochar influences the physical and chemical properties of soil, maize yield under different rainfall conditions, and the cost-effectiveness of its use in smallholder farming systems. Using a quantitative, quasi-experimental design, the study analyzed data from 4,613 plot-level observations across 16 administrative wards.Results indicated that biochar significantly improved bulk density and porosity, thereby enhancing soil structure and moisture retention. Chemically, biochar increased nitrogen, phosphorus, potassium, and organic carbon levels, while soil pH remained stable. Maize yields in biochar-treated plots were significantly higher and more consistent across rainfall gradients. Though biochar increased input costs, it generated higher revenue and absolute returns, confirming its long-term economic viability.The study concludes that biochar is a practical and sustainable soil amendment with the potential to address food insecurity, soil degradation, and climate vulnerability in Zimbabwe's semi-arid zones. Policy integration and community-level adoption are recommended to scale up its benefits across similar agro-ecological regions.