Assessing Future Climate Change on maize Crop Productivity using Aquacrop Model in Southern Mali

Abstract

This thesis investigates the seasonal crop biomass and grain yield of rainfed maize in N’Tarla, situated in the southern region of Mali, through simulation using aquacrop model. The average biomass and grain yield of maize under historical period spanning from 1991 to 2020, encompassing a period of 30 years were found to be 5.14 and 2.16 t/ha, respectively. Trendline analyses reveal a slight decreasing trend for both maize biomass and grain yield, indicating potential challenges to future agricultural productivity. Moreover, significant changes in maize yields were observed. In addition, the ability of CanESM2 downscaled by RCA4 to simulate the future climate of the region was evaluated, demonstrating satisfactory performance. The projected climate trends indicate a continual rise in global temperatures, with the region experiencing increases of up to 6.0°C and 2.7°C in minimum and maximum temperatures, respectively, by 2080 under the RCP 8.5 scenario. Furthermore, rainfall is expected to decrease by 41.6% within the region by 2050 under the RCP 4.5 scenario. The future scenarios highlight the influence of changing rainfall patterns and temperature rise on maize crop yield. A decrease of 0.3% and 1.6% in grain yield was observed under the RCP 4.5 scenarios for the periods 2021-2050 and 2051-2080, respectively, compared to the reference period of 1991-2020. Similarly, all scenarios demonstrated a decrease in biomass yield compared to the baseline period, with the most significant reductions observed under the RCP 4.5 and RCP 8.5 scenarios for the period 2051-2080. Given these findings, it is imperative to adopt adaptation strategies to mitigate the adverse effects of climate change on maize production. Such strategies may include selecting more resilient crop varieties, enhancing water and nutrient management practices, and diversifying production systems to ensure food security and sustainable agricultural development in the face of changing climatic conditions