Biochar’s impact on plant growth is complex, varying with type and application rate. This study explored how four biochars (rice husk, cocoa shell, peanut shell, carob) affect rice (Oryza sativa L.) at five rates (0-5%). Biochar significantly enhanced rice growth, but the optimal type and rate varied. Total dry mass increased by an average of 20% in biochar-treated groups compared to controls, with rice husk and cocoa shell biochar at 5% application rate achieving the highest yields. The effects on plant components differed. While leaf mass fraction responded favorably to all biochar types, stem and root mass fractions remained largely unchanged. Additionally, root strength, as measured by root dry matter content, increased with all biochars, particularly rice husk biochar which boosted it by 8%. All biochar types also enhanced leaf mass per area, a key indicator of photosynthetic efficiency. These findings highlight the importance of tailoring biochar application strategies to specific crops and soil conditions. Optimizing biochar application based on its influence on root strength, leaf mass allocation, and growth across different crop species and soil conditions can unlock its full potential for sustainable development.
