Climate change impacts on rainfed maize production of small-scale cropping systems in Eastern Cape, South Africa

Climate change poses a growing threat to rainfed maize production systems in southern Africa. The region is warming at nearly twice the global average, intensifying climate extremes and disrupting maize development, with small-scale farmers particularly vulnerable due to their limited adaptive capacity and resource access. This study assesses the potential impact of projected future climates on actual water-limited maize yield, phenology, and water stress in small-scale farming systems in the Eastern Cape Province of South Africa. We used five global climate models and the WOFOST model to simulate maize growth and yield under three emission scenarios. Maize responses were assessed at a farm level for the near future (2026–2055) and compared to the historical baseline period (1985–2014). We considered five planting dates and five maize varieties. The results show that the annual average temperature is projected to increase by up to 8.3% coupled with a 95% increase in the number of summer days (day with maximum temperature over 30 °C) under SSP585. Precipitation trends were less consistent and highly variable across years and models. Simulations under conventional management predicted shorter growing cycle duration (by up to 25 days) and grain filling period (by up to 15 days), leading to significant yield losses (up to 14%) under high-emission scenarios, particularly on farms with existing high water stress. However, adaptation strategies, such as early planting and the use of medium-maturity varieties, significantly improved yield performance. These results highlight the combined effects of warming, phenological acceleration, and water stress on maize productivity, while emphasizing the value of localized adaptation. : Adjusting planting dates and selecting suitable varieties offer low-cost adaptation options, but alone may not suffice under future climate conditions. Integrating these with broader strategies is essential for building long-term resilience and ensuring food security under increasingly uncertain agro-climate conditions. • Maize yields decline, with shorter growing cycles and reduced grain filling periods. • Early planting with short-cycle varieties helps reduce climate-related yield losses. • Farm-level adaptation strategies provide efficient, cost-effective climate responses.