Profit efficiency of conventional and conservation agricultural practices among smallholder maize farmers in Zambia

Abstract

Conservation agriculture (CA), based on minimum soil disturbance, crop residue retention, and crop diversification, is promoted as a climate-smart approach to improve smallholder farmers’ resilience amid increasing climate change-related shocks and soil degradation in sub-Saharan Africa. However, CA adoption remains low, and literature on CA profit efficiency is scanty. This study assesses the profitability and profit efficiency of conventional tillage-based agriculture (CT) and CA practices in Zambia. Using a three-wave annual panel dataset of 1,938 household-level observations across contrasting farmer typologies, we apply panel stochastic frontier analysis and a panel tobit model to analyze profit efficiency and identify determinants of efficiency levels. Results show that CA practices, especially minimum tillage with crop rotation, had higher gross margins but lower profit efficiency, with inefficiencies of up to 27.78% for minimum tillage with crop rotation compared to 18.70% for CT. Principal component analysis identified three farmer typologies: asset- and income-poor, asset- and income-rich, and asset- and income-moderate. Notably, asset- and income-rich farmers achieved the highest profit efficiency under CT and full CA (minimum tillage with crop rotation and mulching), while asset- and income-poor farmers achieved the highest efficiency under minimum tillage, minimum tillage with crop rotation, and minimum tillage with mulching. Input costs (notably fertilizer and labor), maize prices, and farmer characteristics such as education, household size, and cooperative membership significantly influenced profit efficiency. The findings underscore the need for context-specific CA promotion, tailored to farmer typologies.