Assessment of climate change impact on the growing conditions and yield of oilseed sunflower in the Northern Black Sea region

Abstract

Objective. To assess the impact of projected climate change on the agroclimatic conditions for growth, development, and yield formation of sunflower in the Northern Black Sea region, with the aim of optimizing cultivation technologies and implementing adaptive management measures in modern agricultural practices to ensure stable and high yields under conditions of climate transformation. Methodology. A modified mathematical model of the water–thermal regime and crop productivity, adapted to the biological characteristics of sunflower, was used to assess growth, development, and yield formation processes. To simulate and analyse potential changes in agroclimatic conditions in the context of global warming, contemporary climate change scenarios–Representative Concentration Pathways (RCP)–were applied. Results.The study presents a comprehensive analysis of the agroclimatic conditions in the Northern Black Sea region for the period 2021–2025, taking into account projected climate changes under the RCP2.6 and RCP6.0 scenarios. The assessment was conducted for the following sunflower growth stages: “emergence – flowering,” “flowering – physiological maturity,” and the full “emergence – maturity” period. Modelling results indicate a consistent trend toward increasing temperatures throughout the year under both scenarios. The most pronounced moisture deficit is expected during the summer months, as evidenced by a decrease in the hydrothermal coefficient (HTC ≤ 0.6), which signals drought-prone conditions during active vegetation.Climate change is projected to cause a significant shift in the crop’s phenological stages. Specifically, sowing dates are expected to occur 16–17 days earlier, resulting in earlier emergence (by 14–15 days), flowering (by 6–7 days), and harvesting (by 12–13 days). During the first interphase period (“emergence – flowering”), favourable conditions are expected for achieving relatively high crop productivity under both scenarios. The maximum leaf area index atthe onset of flowering is projected at 2.5 m²/m² (RCP2.6) and 3.4 m²/m² (RCP6.0), while the maximum increase in dry biomass will reach 156 g/m² and 171 g/m², respectively.However, in the second interphase period (“flowering – maturity”), when seed formation and filling occur, increasing aridisation of the climate is anticipated, negatively affecting yield. The projected sunflower seed yield is estimated at approximately 1.6 t/ha under RCP2.6 and 2.2 t/ha under RCP6.0–two to three times lower than the crop’s potential productivity in the region. These results highlight the necessity of adapting cultivation technologies to the anticipated climatic challenges in the near future. Conclusions. To ensure stable and high sunflower seed yields under the increasing aridisation of the Northern Black Sea climate, the introduction of adaptive measures, particularly irrigation, is advisable. The findings demonstrate that under the projected climate scenarios (RCP2.6 and RCP6.0), without supplementary water sources, the productivity potential of the crop cannot be fully realised. The adoption of modern irrigation systems would partially offset moisture deficits during critical growth stages and ensure stable yields under changing climatic conditions.