Agricultural development in sub-Saharan Africa remains trapped in a yield-centric paradigm that confuses biological output with economic welfare. This study conducted a comparative, full-cost profitability analysis of six vegetable crops: Amaranthus, Okra, Cucumber, Ewedu, Pepper, and Tomato, cultivated by 30 smallholders under the Sasakawa Africa Association’s Family Business Garden intervention in Benue State, Nigeria. Economic Farm Income (EFI) and Return on Investment (ROI) were calculated using full-cost accounting. ANOVA with Tukey HSD assessed profitability differentials; break-even and portfolio variance examined risk resilience. Three paradigm-shifting findings emerge. First, high-value crops (pepper: ₦447600/ha; tomato: ₦424,100/ha) generate EFI values 2.8 times greater than low-value ewedu (₦158,400/ha), rejecting the low-cost, short-cycle advantage hypothesis. Profitability is driven by unit price ( r = 0.89), not yield ( r = 0.31). Second, coefficients of variation are statistically indistinguishable across all six crops (CV = 0.20–0.25), revealing constant proportional risk (σ = kµ, k ≈ 0.25). Low-value crops offer no proportional safety advantage. Third, specialized pepper achieves superior risk-adjusted returns (mean/SD = 4.43) versus diversified portfolios (4.15), rejecting diversification advantage under constant relative risk. Break-even analysis delivers the final policy reversal: pepper (44.7%) and tomato (42.1%) provide the largest margins of safety, while ewedu offers only 13.5% downside protection. Education is the strongest profitability correlate (ROI: r = 0.41, p < 0.001). Closing profitability gaps, not yield gaps, emerges as the singular pathway to smallholder economic transformation.
Fadairo et al. (Sat,) studied this question.