S. Atanasova
Department of Plant Sciences, Faculty of Agronomy, Trakia University, 6000 Stara Zagora, Bulgaria
(Manuscript received 26 June 2026; accepted for publication 30 August 2026)
e-mail: stanislava.atanasova@trakia-uni.bg
Abstract: The present study evaluates the impact of organic fertilization on the biometric and productive indicators of the ‘Polka‘ raspberry cultivar under the influence of combined abiotic stress – transplant shock, drought, and extreme high temperatures (2025). The experiment was conducted at the experimental field of the Faculty of Agriculture at Trakia University, using a planting scheme of 2.20 x 0.30 m. The main objective of the research is to determine the potential of organic fertilization to mitigate the negative effects of stress and maintain the productivity of the plantation. Vegetative parameters (number, height, and diameter of shoots) and reproductive indicators (yield and fruit weight) were analyzed. The results show that the extreme conditions in 2025 severely suppressed vegetative growth in the control (unfertilized) plants, where shoot height and thickness decreased by 50.4% and 47.6%, respectively, compared to the previous year. Organic fertilization exhibited a pronounced buffering effect, maintaining a better vegetative habitus and an optimized shoot density (14.3 shoots/m). This led to a 37.16% higher yield in the fertilized variants (1154.9 g/m) and preserved the standard fruit size under drought conditions. The study proves that organic fertilization is a key factor for enhancing resilience and maintaining raspberry productivity under abiotic stress.