Climate-adaptive agronomic strategies for proso millet (Panicum miliaceum) production in tropical savanna regions

Abstract:

Proso millet (Panicum miliaceum L.) possesses exceptional climate resilience characteristics, yet optimized agronomic management strategies for its production under the variable conditions of tropical savanna regions remain underdeveloped. This research evaluated six climate-adaptive agronomic strategies conventional tillage, minimum tillage, mulch retention with minimum tillage, ridge-furrow planting, deficit irrigation, and early sowing for their effects on proso millet grain yield, water use efficiency, and soil moisture conservation in the Cerrado region of São Paulo State, Brazil, over two consecutive growing seasons (2022-2023 and 2023-2024). A randomized complete block design with four replications was employed at the São Paulo Foundation for Agricultural Research experimental station. Results demonstrated that the ridge-furrow planting system achieved the highest mean grain yield at 2,140 kg ha⁻¹, representing a 50.7% improvement over conventional tillage (1,420 kg ha⁻¹), followed by deficit irrigation at 2,380 kg ha⁻¹ when supplemental water was available. The combination of minimum tillage with surface mulch retention enhanced soil moisture conservation by 34.2% and improved water use efficiency by 41.6% compared to conventional management. Water budget analysis revealed that transpirational water use constituted 38.2% of total seasonal water input, while soil evaporation losses represented 28.4%, identifying evaporation suppression as the primary target for water conservation interventions. The cumulative yield gain achievable through integrated adoption of all five improved strategies was estimated at 1,220 kg ha⁻¹ above the conventional baseline, representing an 85.9% enhancement. These findings provide an evidence-based framework for climate-adaptive proso millet production in tropical savanna agroecosystems and support the crop's expanded role in climate-resilient agricultural diversification strategies for the Brazilian Cerrado.