Long-term organic versus conventional system comparison for productivity, profitability and soil health

Abstract

The challenge of feeding a growing population while preserving soil resources has intensified the organic-versus-conventional debate, yet few long-term side-by-side trials exist in sub-Saharan Africa. This research compared organic and conventional maize-soybean systems over ten years (2013-2023) at the University of Pretoria’s Hatfield Experimental Farm, measuring grain yield, economic returns, and soil health indicators. Organic yields started 25% below conventional but converged by year 7 and exceeded conventional by 4.8% in the final three years. Organic profitability surpassed conventional from year 5 onward due to premium pricing and lower input costs. SOC under organic management increased by 41.3% versus a 7.8% decline under conventional. These findings challenge the assumption that organic systems inherently sacrifice productivity.