Climate-adapted millet intensification: sustainability assessment across three agroecological zones in Niger

Abstract Climate change undermines the resilience of farming systems in the Sahel, increasing population vulnerability. In this study we evaluated millet intensification options to enhance production and climate adaptation through sustainable practices in Diffa, Maradi, and Zinder, Niger. The methodology used was field experiments and a sustainable intensification assessment framework to evaluate the performance of six systems (Direct sowing without fertilization; Direct sowing with organic micro-dosing; Direct sowing with mineral micro-dosing; Transplanting without fertilization; Transplanting with organic micro-dosing; Transplanting with mineral micro-dosing). A Sustainability Index (SI) > 1 indicates a system that is productive, economically viable, environmentally friendly, socially beneficial, and supportive of human well-being. The results showed high significant difference between sowing mode and fertilization option factors (p = 0.001), but not for the combination of 2 factors across all 3 regions. In contrast, direct sowing combined with mineral micro-dosing yielded better results than other treatments (biomass yield = 3533.3 kg/ha; grain yield = 539.5 kg/ha) while transplanting combined with no fertilization yielded less (biomass yield = 2256.3 kg/ha; grain yield = 254.8 kg/ha). The same trend is observed in Maradi and Zinder. However, transplanting showed the shortest cycle with 83–85 days after sowing compared to drenching before sowing and direct sowing modes. For sustainability, the intensification assessment framework showed that systems 5 (mineral micro-dosing combined with direct sowing mode) and system 6 (organic micro-dosing combined with direct sowing) led to increased performance with better sustainability index (SI = 1.29 and 1.22 in Diffa; 1.48 and 1.17 in Maradi). The highest sustainability index is observed in the Zinder region for system 2, which combines organic micro-dosing with transplantation. This promotes efficient nutrient use and strengthens the resilience of dry land farming systems. Farmers and policymakers can use the provided information to determine the appropriate systems based on social and economic conditions and agroecological zones.