Sustainable Intensification of Sorghum and Pearl Millet Production by Seed Priming, Seed Treatment and Fertilizer Microdosing under Different Rainfall Regimes in Mali

Sorghum and pearl millet are the most important stable crops in the drylands of West Africa. This four-year study based on two experiments assessed different low-cost methods for intensification of sorghum and millet production under contrasting rainfall conditions in Mali. Experiment 1 assessed the microdosing rates 0, 0.2, 0.4, 0.6 and 0.8 g NPK hill⁻¹ combined with seed priming across four locations in Mali while Experiment 2 assessed the cumulative effects of the seed priming, seed treatment with pesticide, microdosing and urea top dressing. In central Mali, there was a clear effect of seed priming while there was no such effect in southern Mali with better rainfall conditions. In central Mali, the microdosing rate of fertilizer of 0.4 g NPK hill⁻¹ (4 kg NPK ha⁻¹) performed best, while in southern Mali the microdosing rate of 0.8 g NPK hill⁻¹ (20 kg NPK ha⁻¹) gave the best result. Experiment 2 showed that there was a clear effect of top dressing of 1 g urea hill⁻¹ (25 kg urea ha⁻¹) in southern Mali while no such effect was apparent in central Mali. In general, there was a better response to microdosing in sorghum than in pearl millet. A decision tree for crop and fertilizer management in Mali was developed, taking into consideration rainfall, crop choice, use of seed priming and microdosing rates.