Assessment of climate change impact on rainfed corn yield with adaptation measures in Deep South, US

Invariable warming trends of global climate and increase in uncertainties in seasonal precipitation are major threats to crop production and subsequently, to food security. Simulation is needed to understand the suitability of potential adaptation strategies to mitigate the impacts of uncertain climate change scenarios on agricultural production. This study investigates the influence of climate change on maize yield in the Mobile River Basin (MRB) in the southeastern United States using the Decision Support System for Agrotechnology Transfer (DSSAT) crop model. We use four climate models from Coupled Model Intercomparison Project Phase 6 (CMIP6) under two Shared Socio-economic Pathways (SSPs) of SSP245 and SSP585 to represent future changes in solar radiation, precipitation and temperature. In this study, we simulate crop yields using climate data from the past (1985-2010), the experimental period (2011-2017), and future projections (2026-2050, 2050-2075, and 2076-2100). The simulated crop yields are compared to historical yields to evaluate the adaptation measures selected to mitigate the impact of future climate scenarios, assuming no effective adaptation measures or changes in farming practices. The findings indicated that by end of the 21st century, maize yield will fall by 8.2 % (-842 kg.ha(-1)) and 16.4% (-1684 kg.ha(-1)) under the SSP245 and SSP585 scenarios, respectively. Future climate change will have a significant impact on maize production in MRB, and will require optimal adaptation measures to manage agricultural production loss. We evaluate several adaptation strategies including optimization of planting date, fertilizer application date, implementing supplemental irrigation and modification of fertilizer doses. The study concludes that significant improvement in corn yield under the changed climatic patterns assumed as per the SSPs considered, is possible by planting one week ahead, fertilizing two weeks ahead, and using suitable supplementary irrigation during the cropping season. The findings of this study can be utilized in adapting to climate change and advancing sustainable agricultural development in the MRB.