Bioscience Evidence 2026, Vol.16, No.4, 291-303 http://bioscipublisher.com/index.php/be 295 3.4 Water availability Blueberry has a shallow root system and relatively limited water uptake capacity, making it highly sensitive to changes in soil moisture. Both prolonged drought and excessive irrigation can negatively affect fruit development and bioactive compound accumulation. However, moderate water regulation does not always reduce fruit quality and may improve certain quality traits under specific environmental conditions. Ordóñez-Díaz et al. (2020) conducted a field experiment in southwest Spain and found that moderate deficit irrigation did not significantly reduce major blueberry fruit quality parameters but increased fruit firmness. This indicates that under Mediterranean climatic conditions, precisely controlled irrigation reduction can save water while maintaining or even improving commercial fruit quality. Although moderate water stress may have beneficial effects within a certain range, prolonged or severe drought significantly reduces blueberry quality. Continuous water deficiency suppresses photosynthesis, reduces chlorophyll content, and affects carbon assimilation and nutrient transport, ultimately limiting fruit development and bioactive compound accumulation. Moderate abiotic stress may activate antioxidant systems and increase some bioactive compounds, but this positive effect occurs only within a limited stress range (Krishna et al., 2023). Once water stress exceeds the plant tolerance threshold, vegetative growth, canopy function, and fruit enlargement are severely affected, and the negative effects become greater than the potential benefits from increased secondary metabolites. 3.5 Soil properties Soil conditions are fundamental factors affecting blueberry growth and fruit quality formation, among which soil pH is particularly important. Blueberry is a typical acid-loving fruit crop and grows best in acidic soils with high organic matter content, good drainage, and sufficient aeration. Ochmian et al. (2021) reported that the suitable soil pH range for blueberry cultivation is approximately 3.8–5.5 and compared different soil amendment methods. Sulfur application effectively reduced soil pH and improved soil suitability for blueberry growth, while some soil types, such as silty loam soils, remained difficult to adjust even after amendment. This indicates that not all soils are equally suitable for blueberry production. Unsuitable soil pH directly affects blueberry physiological functions. Yang et al. (2022) found that high-pH stress significantly reduced leaf SPAD values, net photosynthetic rate, transpiration rate, and stomatal conductance, while also altering osmotic regulation and antioxidant systems. As a result, different cultivars showed varying degrees of growth inhibition under alkaline conditions. High soil pH not only reduces blueberry yield but also weakens fruit quality and nutritional value by restricting nutrient uptake and disrupting normal physiological processes. Therefore, maintaining an appropriate acidic root-zone environment is a fundamental requirement for stable blueberry production and high-quality fruit formation. 4 Production Management Practices for Improving Blueberry Fruit Quality 4.1 Fertilization management strategies Fertilization is an important production practice affecting blueberry fruit quality. Its role is not only to promote plant growth and increase yield but also to directly regulate the accumulation of bioactive compounds such as anthocyanins and phenolics. Blueberry has a shallow root system and is highly sensitive to nutrient availability. Insufficient fertilization can limit plant growth and fruit development, while excessive fertilization, especially excessive nitrogen supply, may promote excessive vegetative growth, increase competition between shoots and fruits for assimilates, and reduce the accumulation of bioactive compounds. Mecozzi et al. (2026) investigated the effects of different nutrient supply levels on fruit quality of ‘Duke’ blueberry (Vaccinium corymbosum L.) grown under soilless conditions in Italy. The results showed that lower nutrient supply favored higher anthocyanin content and antioxidant capacity, while increased nutrient availability promoted vegetative growth, yield, and some phenolic compounds but did not further enhance anthocyanin accumulation. These findings indicate that high yield does not always correspond to high fruit quality, and excessive nutrient input beyond plant requirements may not be converted into quality advantages. For commercial orchards, fertilization programs should therefore be optimized according to fruit quality formation, maintaining a
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