Unravelling the contribution of G × E × M interactions to maize productivity in Central Mozambique amid climate change

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Maize is the most important staple food in sub-Saharan Africa. Yet, smallholders produce on average about 20% of what is possible with best agronomic practices. On-farm experiments were conducted over two consecutive cropping seasons in Central Mozambique to investigate the contribution of genotype-by-environment-by-management interactions to maize yields in relation to improved cultivars, sowing time, and fertilization regimes across soil fertility conditions. In 2022–2023, maize yield variability on high-fertility fields was explained by a three-way interaction between fertilizer regime, sowing date, and cultivar, whereas on low-fertility fields, it was explained by fertilizer regime only. The highest yields were observed with early sowing of an intermediate (3.6 t ha −1 ) or early (3.1 t ha −1 ) maturity cultivar, whereas late sowing yielded the least (1.6 t ha −1 ). In 2023–2024, characterized by a severe El Niño drought, yield variability was explained by cultivar on high-fertility fields (with the intermediate maturity cultivar yielding highest) and by fertilizer regime on low-fertility fields. Results from farmer-managed experiments conducted in the same season confirmed the importance of cultivar choice and fertilizer use. Profitability with improved maize cultivars and mineral fertilizers depended on soil fertility and on the extent of water limitations to maize growth, with trade-offs arising between food security and return on investment when improved genetics and agronomic management were used. Targeting intermediate maturity maize cultivars with early sowing and fertilizer inputs was found to be critical to improve food security amid climate change.